JPH05500243A - Environmentally improved bleaching method for lignocellulosic materials - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention does not require the use of elemental chlorine, yet produces pulp with acceptable strength. Delignify (bleach) the lignocellulose bulb Relating to a novel environmentally friendly method for Also, the use of this method is an environmental pollutant. Reduce the amount of dyeing material.

Background of the invention Wood has two main components: fibrous carbohydrates, e.g. cellulosic parts and non-fibrous parts. Contains components such as The polymer chains that form the fibrous cellulose portion of wood are aligned with each other and forms strong associative bonds with adjacent chains. The non-fibrous parts of the wood are three-dimensional mainly formed from phenylpropane units, known as Contains polymeric substances. Some of the lignin is between the cellulose fibers and binds them together. Although bound to body materials, a significant portion of lignin is also distributed within the fibers themselves. It is.

To be used in papermaking processes, wood must first be converted into pulp. The pulp is , slurried or suspended and then deposited on a screen to form a sheet ( For example, it can be defined as a wood fiber that can form a sheet of paper). Pal The methods used to carry out the plating process usually involve physical or chemical treatment of the wood. treatments, or a combination of these two treatments, that change the chemical form of the wood. , and impart desired properties to the resulting product. Thus, two major types of parameters pulping techniques, namely mechanical pulping and chemical pulping. With mechanical valves The wood is physically separated into individual fibers. In chemical pulping, wood chips is digested in a chemical solution to solubilize some of the lignin, thus allowing its removal. do. Commonly used chemical pulping methods are (1) soda method, (2) sulfite method. and (3) broadly classified as Kraft methods, with the last method being the most commonly used; Moreover, various known improvements described below can be made.

The soda method is well known in the art. It breaks down lignin and helps in its removal Sodium hydroxide (NaOH) is used as the active reagent for this purpose. Also, sulfite Salt methods are known in the art (e.g. Handbook for Pu1p & Paper Technologists-Chapter 6; 5ulfite Pu lping(TAPPl, u, s, A, )).

The Kraft process, along with its many variations, describes the basic chemistry used in paper production. It's a method. Handbook for Pu1p & Paper Tech Nologists-Chapter 7; Kraft Pulping (TAPPl, U The basic raft method, as described in is evaporated in an aqueous solution of sodium hydroxide (NaOH) and sodium sulfide (NaJ). It involves understanding. This method only works with more difficult-to-treat woods such as southern conifers. However, other types of northern hardwood and softwood wood are more easily pulped. Very effective in pulping seeds. Similarly, the Kraft method generally produces relatively high strength Manufacture Nokurupu. After all, its use reduces the cellulose content of wood. This is because less erosion occurs.

Improved kraft technology reduces the thread reamer structure of cellulose fibers during pulping. loss of strength of the resulting paper product compared to normal kraft compared to paper products produced by conventional methods. One improved kraft pulping method is known as “extended delignification,” which in sequence or at different locations within the Guijiester apparatus or at different times; or while reducing the severity of the chemical attack of pulping liquid on cellulose fibers. cooling liquid in a prescribed order to more effectively remove larger amounts of lignin. Various improved craft techniques such as removing, reinjecting and adding pulping chemicals is a broad term used in the art to include. Other improvements to the craft method are Kraft = AQ method, and in this method a small amount of anthraquinone is converted into kraft pulp. The cellulose fibers that make up wood are limit erosion to fibers.

Various other extended delignification techniques are known in the art, including TAPPI , vol. 68 (11), 70 (+985), V, NKOortelainen and Masu, N Kamyr modified continuous steaming as described by Backlund. Boiled (MCC); R in TAPPI, Volume 06 (3), 120 (1983), S.

Beloit fast displacement heating as reported by Grant (RDH); and Pu1p and Paper, Volume 59 (11), 90 ( (1985) by B, Pettersson and UB, Ernerfeldt. ■ Sands Cold Bl as reported ow) including steaming.

Cooking wood by the kraft or modified kraft process is known as “brownstock”. A dark slurry of cellulose fibers known as ``rownstock'' bring about success. The dark color of brownstock comes from the fact that all of the lignin is removed during cooking. This is due to the fact that it is chemically modified during pulping to form chromophore groups. There is. Thus, in order to lighten the color of a brown stock bulb, i.e. to make it suitable for use as printing and writing paper and other blank paper applications. by the addition of delignifying substances and as “bleaching” or “whitening”. Chemically converting residual lignin into colorless compounds by known methods It is necessary to continue removing residual lignin.

However, before bleaching the pulp, the chemical treatments involved in the pulping process must be completed. After being drained, the cooking material is typically transferred to another blow tank. in the blow tank , the pressure generated during the initial chemical processing of the lignocellulosic material is released and the pulp The fibrous material is separated into fibrous material. The resulting fibrous material is then subjected to a series of washing steps. residual chemicals and solubles separated from the fiber material during the pulping process Remove combinations of substances (eg lignin). Often the pulp is also undefined for further processing (re-steaming, mechanical grinding, etc.) (ered) one or more screens designed to separate the bulk of the wood Processed.

The residue obtained from the washing process (commonly referred to as black liquor) is collected and concentrated. , and then incinerated in an environmentally safe manner in a recovery boiler. Collection, concentration and collection of black liquor Techniques relating to combustion and combustion are conventional and known in the art.

Delignification and bleaching processes involve selected combinations of chemical reactants. This is done on the textile material washed in the step →. In the conventional technology, Various combinations of chemical treatments have been suggested. Furthermore, the individual processing steps are mostly They were rearranged in an infinite number of combinations and permutations. Therefore, various bleaching processes To simplify the description of bleaching and bleaching systems, the use of letter codes is commonly used in combination to describe chemical reactants and the order of steps in a process. It will be done.

Below, the character codes used in appropriate places are as shown in τ.

C=chlorination-reaction with elemental chlorine in acidic medium.

E = Alkaline extraction - dissolution of reaction products with NaOH.

E, = oxidized alkali extraction - dissolution of reaction products with NaOH and oxygen.

D = chlorine dioxide - 010. in acidic medium. reaction.

P=peroxide-reaction with peroxide in alkaline medium.

0=oxygen-reaction with elemental oxygen in alkaline medium.

0.2 Improved Oxygen - Uniformity of pulp of low to medium consistency Alkaline treatment followed by reaction of high consistency pulp with oxygen.

Z=Niodine reaction with ozone.

2. = Improved ozone-uniform reaction with ozone.

C/D - Mixture of chlorine and chlorine dioxide.

H = hypochlorite - reaction with hypochlorite in alkaline solution.

0, and Z are improved processes of the present invention and are described in more detail in the detailed description of the invention. explained.

Wood valves can be delignified and bleached by using elemental chlorine. , has been the norm for many years. An illustration of bleaching lignocellulose bulbs is For example, U.S. Patent No. 1.957.937 to Campbe et al. U.S. Pat. No. 2,975,169 to Ford et al.; National Patent No. 3.462.344 specification and Handbook for Pu 1p & Paper Technologists-Chapter 11; Bleach ing (@11.3) (sAPPI, This is the process disclosed in USA).

However, while elemental chlorine was found to be an effective bleaching agent, it difficult to handle and potentially dangerous to both individuals and equipment. for example, Effluents from chlorine bleaching processes are produced as a byproduct of these processes. Contains large amounts of chloride. These chlorides easily corrode processing equipment, thus The construction of such factories requires the use of expensive materials. Furthermore, chloride in the factory The accumulation of material does not use recovery systems that require extensive and therefore expensive modifications. and eliminates recycling of washer filtrate after the chlorination step in closed system operation. .

In addition, chlorinated organics in effluents (U.S. Environmental Protection Agency Concern about the potential environmental effects of The requirements change considerably and cannot be met by conventional bleaching or pollution control techniques. Allow bleaching plants that contain standards such that they cannot be bleached.

To avoid these deficiencies, the paper industry has developed a multi-stage process for lignocellulosic pulp. Reduce or eliminate the use of elemental chlorine and chlorine-containing compounds from bleaching processes That's what I was trying to do. A high level of pulp brightness makes it difficult to use such pulps. The demands required for many applications complicate these efforts. There is.

In this regard, chlorine-containing agents are used, for example with oxygen, for the purpose of bleaching the pulp. Efforts have been made to develop replacement bleaching processes. The use of oxygen is This allows for the circulation of the effluent from this stage for recovery and also reduces the amount of elemental chlorine used. allows for a considerable reduction in Some methods of bleaching pulp with oxygen and delignifying it For example, the methods of Richer, US Pat. No. 1. , No. 860.432, Gran U.S. Pat. No. 2.926.114 and U.S. Pat. No. 3.024.158 to Gaard et al. , U.S. Patent No. 3.274.049 to Ga5chke et al., U.S. Pat. Patent No. 3.384.533, U.S. Patent No. 3.251.73 to Watanabe No. 0, U.S. Patent No. 3.423.282 to Rero-11e et al., Farley U.S. Pat. No. 3.661.699, Kooi U.S. Pat. No. 4.619.733 and “Bleaching of 5ulf” by Christensen, P. ate Pu1ps with Hydrogen Peroxide'', N orsk Skogindustri, 268-271 (1973) proposed It was Alkaline pretreatment of pulp before oxygen delignification was carried out by Elton in the United States. This is suggested by U.S. Pat. No. 4,806,203.

However, the use of oxygen is a completely satisfactory solution to the problems seen with elemental chlorine. isn't it. Oxygen is not as selective a delignifying agent as elemental chlorine and is a common acid The KNo of pulp using the elementary delignification method is due to the disproportionality of cellulose fibers. It can be reduced by a limited amount until there is fair erosion, ie, unacceptable erosion. Also After oxygen delignification, residual lignin is conventionally removed, typically by chlorine bleaching. chlorine was removed to obtain a well-bleached pulp, but with a greatly reduced amount of chlorine. was using. However, even at such reduced chlorine concentrations, corrosion The chemical chlorides eventually reach unacceptable concentration levels during closed cycle operation.

Avoid this by using ozone during chemical pulp bleaching to avoid the use of chlorine bleach. Attempts have already been made to remove residual lignin. Ozone was originally a lignocell It appears to be an ideal substance for bleaching loin material, but the unusual acidity of ozone oxidation and its relatively high cost have traditionally made lignocellulosic materials, especially southern needles, This has limited the development of satisfactory ozone bleaching methods for leaf trees. Ozone and lignin Although it reacts easily and effectively reduces KNo, it also reduces carbohydrates under most conditions. (which makes up the cellulose fibers) and the strength of the resulting pulp decreases. Similarly, ozone has p lignocellulose is very sensitive to process conditions such as may significantly alter the reactivity of ozone towards substances.

Since about the turn of the century, when ozone's delignification ability was first recognized, To develop a commercially suitable method of using ozone for bleaching nocellulosic materials. Considerable and continuous research has been carried out by many persons skilled in the art. A permit has been issued in this field and an attempt is made to carry out ozone bleaching on a non-commercial medium scale basis. There was a report. For example, Brabender et al., U.S. Pat. No. 2.466,63 Specification No. 3 specifies that ozone has a moisture content of 25 to 55% (oven-dried consistency). ) and the bleaching method is passed through the pulp with pH adjusted in the range of 4 to 7. It is listed.

Other non-chlorine bleaching sequences include S, ROthenberg, D, Robtn. “Bleaching of” by Son and UD, Jo Sonbaugh Oxygen Pu1ps with 0zone”, Tappt, 182- 185 (1975) -Z, @ZBZ.

ZP and ZP, (P, -peroxyacetic acid); and N, by 5oteland , “Bleaching of Ch-mical Pu1ps WHh Ox ygen and 0zone'', Pu1p and Paper Magaz ine of Ca ≠ р=G T 153-58 (1974)-0ZEP, OP and ZP.

In addition, U.S. Patent No. 4.196.043 of S. discloses a law that also attempts to eliminate the use of chlorine compounds, and specifically Includes examples related to hardwoods. It is true that hardwoods are easier to bleach than most softwoods. It is known to those in the industry. This method involves one to three bleaching steps and an alkaline peracid It is characterized by a final treatment with hydrogen chloride, and each stage is separated by alkaline extraction. There is. One such sequence is the paper industry's common shorthand nomenclature as ZEZEP. Can be described. According to this method, the effluent from each treatment stage is preferably earlier than the stage at which it is obtained, it is collected and recycled for use in the bleaching operation. can be done. This patent also provides a so-called countercurrent effluent flow.

Despite all the research conducted in this field, ozone bleached lignocellulose - A commercially viable method for the production of pulp, especially southern softwood valves, is It has not been disclosed since then, and many failures have been reported.

The present invention solves the problems found in the prior art as described herein, and Virtually eliminates chlorinated organic emissions and minimizes coloration and nOD emissions to make it commercially viable. pulping and bleaching processes to produce high-grade bleach valves in a viable manner. Therefore, it is an object of the present invention to produce lignocellulose pulp without the use of elemental chlorine bleach. Delignifies and bleaches plastics to substantially reduce or eliminate contamination of the environment. Optimize the physical properties of the valve in an energy-efficient, cost-effective manner The objective is to provide a multi-step method for The present invention uses coniferous trees from the southern United States that are difficult to bleach. Applicable to virtually all wood species including:

The method of the invention comprises three or more steps with several possible variations within and between steps. including. These steps can be described as follows.

The first step is to produce wood chips using one of several chemical pulping processes. delignification from the pulp to lignocellulosic valves, followed by circulation and recovery. Involves cleaning removal of most of the dissolved organic matter and cooking chemicals. Not separated by pulping Screening of the pulp to remove fiber bundles is usually carried out. This de-rig For conifers in the southern United States, the nitrification process, for example, KNo ranging from about 21 to 28 (CED) ″) viscosity and a GE whiteness in the range of about 15 to 25 is typically obtained. It is done so that it is done. For hardwoods in the southern United States, approximately lθ ~ 14 (target 12.5 ) and a CHD viscosity of about 21-28. It will be done.

Among the advantageous embodiments of this first step are a. a continuous or batch cooking stage; Kraft pulping used: b0 stage alkali addition and countercurrent final cooking continuous cooking kraft pulping with extended delignification; Extended delignification using C0 high velocity liquid displacement technology and cold blowing technology Batch cooking kraft pulping with continuous or batch cooking stages; d. Craft with extended delignification using floors - AQ bulbization There are, but are not limited to:

The extended delignification techniques described in (b) and M(c) above may include, for example: Camino LICC technology, Beloit RDH technology and It may also include Sands cold blow cooking technique. Lignocellulose used Depending on the type of gas material, the soda method and sulfite method described above may be used.

The second step of the method allows the lignin to be removed without appreciable loss of strength of the cellulose fibers. including an oxygen delignification treatment to further remove . This is for circulation and collection. This includes washing and removing dissolved organic matter and alkalis. Also, valve screening It is sometimes performed after oxygen delignification.

During the oxygen delignification process, the KNo of the increased consistency valve is at least about 45% (with respect to 0) with little damage to the cellulose content of the pulp. ) to at least about 60% (with respect to 01). In addition, KNo of pulp, The ratio of viscosity to viscosity is typically reduced by 25%. For wood pulp, a KNo of about 7 to 1O and a viscosity of about 13 or more can be readily obtained. Ru. For hardwood pulps, a KNo of about 5 to 8 and a viscosity of about 13 or higher Obtained after a ligninization step.

Among the possible embodiments for this step: a, low pulp consistency, intermediate pulp consistency, or high pulp Conventional oxygen deriging including alkaline oxygen treatment of pulp in consistency sea Ninated (0); or low pulp consistency to medium pulp consistency (i.e. about 10 pulp consistency) alkaline treatment at a high pulp consistency (less than (i.e., greater than about 20% by weight), but are not limited to these preferred embodiments (0,). Not determined.

Valve end uses that do not require whiteness above about 35% GEB (often semi-bleached) (referred to as white pulp), which is directly processed only by step 2 in the papermaking process. It is possible to use a valve with

The third step of the method is a highly selective treatment of lignin with minimal degradation of cellulose. Acidic gas ozone at specific process parameters to obtain removal and bleaching bleaching treatment (Z or Z). Among these process parameters, gold Chelating agents for controlling genus ions, pH control, valve particle size control, valve conditioning There are pressure, ozone concentration and gas/valve contact adjustments. Treatment with ozone Before adding chelating agents such as oxalic acid, diethylenetriaminepentaacetic acid (“D TPA'') or ethylenediaminetetraacetic acid (EDTA'') is added to the pulp. may bind significantly to the metal ions contained therein. Furthermore, the valve Preferably, the pH of is adjusted to a range of about 1-4 before the third step. this is , by adding a sufficient amount of acidic material to the valve. advantageously The consistency of the valve is increased to about 35-45% by weight and the fiber floc Before the ozone delignification process, the particle size of . A washing step of dissolved organic matter is included for circulation and recovery.

During the ozone process, the pulp is heated to ambient temperature or at least about 49°C (120@F). Preferably, the valve temperature is maintained below. Ozone is, for example, oxygen or It may be provided by an ozone-containing gas which may include air. Ozone/oxygen mixture If ozone is used, the ozone concentration is preferably about 1-8% by volume, while , ozone concentrations of about 1-4% by volume are allowed for ozone/air mixtures. ozo In the nuclear reactor, the substantially delignified valve contains substantially all of the valve grains. The process proceeds by exposing children to ozone in a uniform manner.

Pulp with a KNo greater than about 1O after the second step has a significant amount of ozone is required to reduce KNo, to the desired level (this is typically The properties of the valve are poor due to excessive ozonolysis of the cellulose fibers of the pulp. may be harmfully affected), are found to be unsuitable for this third step. Ta.

If a valve with a KNo of less than 10 is ozonated, a small concentration of ozone is used and only a minimal amount of cellulose degradation occurs. Needles from the southern United States of the above raw materials The products from this ozonation process for leaf or hardwood trees are generally less than about 5 KNo in the range of about 3 to 4 (target 3.5), viscosity of about 10 or more, and less 50% for both (typically about 54% or more for softwoods and 63% for hardwoods) This bulb has a GE whiteness of (above).

Among the embodiments useful for this step: a. Acidified gas by countercurrent contact of oxygen or ozone in an air carrier gas. or acidified gas by co-current contact with oxygen or ozone in an air carrier gas. Processing loops There are, but are not limited to:

An additional bleaching step is then performed using several possible well-accepted bleaching processes. and an extraction process to bring the bulb to the desired fully bleached state, i.e. approx. It may be used to have a GE brightness level of 70-95%. Yes Among the effective implementations: a. Normal extraction step with washing followed by peroxide step with washing; (i.e. BP );b1 Normal alkaline extraction and washing steps followed by normal dioxide with washing chlorine stage (i.e. ED); C9 Normal alkaline extraction and washing steps followed by normal chlorine dioxide with washing step followed by repeated extraction steps and chlorine dioxide steps (EDED); and d, an extraction step with increased oxygen or oxygen and peroxide, followed by normal salt dioxide Elementary stage: i.e., (B,　)D or (H,,)D, but not limited to these. stomach.

In another embodiment, the extraction step extracts the substantially delignified pulp from the buffer. Correlates with the amount of alkaline substances that solubilize a significant portion of the lignin remaining in the lubricant. alkaline aqueous solution at a predetermined temperature for a predetermined time period concerned may include combining an effective amount of an alkaline substance in the composition. Then Arca Extract a portion of the aqueous solution to remove substantially all solubilized lignin from it. can be removed.

Following the extraction stage, the substantially delignified pulp is treated with an additional bleaching step It is possible to increase the GE whiteness of the resulting bulb by a small amount (up to about 70%). Wear. Preferred brighteners include chlorine dioxide or peroxide.

(E,)D embodiment, (E,,)D embodiment or EDED embodiment is the highest Obtain a whiteness level of . For ED embodiments, the filtrate of the chlorine dioxide stage is treated with Otherwise, it cannot be recycled for drug recovery due to the presence of inorganic chlorides. however, Since this is the only required sewage filtrate from the method, the volume of effluent, color, Significant reductions in COD, BOD, and chlorinated organics are obtained. per ton Colored materials less than 2 bonds per ton, BOD less than 2 bonds per ton, BOD 5 and less than 2, A total organic chloride σ0CI) of preferably less than 0.8 can be obtained. Also, two The filtrate from the chlorine oxide stage is treated with a membrane filtration process that allows virtually complete circulation. It is possible to do so. In EP embodiments, the chlorinated material is Virtually all liquid filtrate can be circulated and collected, with almost no effluent produce a method.

Brief description of the drawing FIG. 1 is a block process diagram of a preferred method of the present invention, with solid lines indicating pulp flow. The dashed line represents the flow of the effluent.

FIG. 2 is a schematic diagram of a preferred method of the invention.

FIG. 3 is a cross-section of the portion of the ozonator shown in FIG. 2 taken along line 3-3. It is a diagram.

FIG. 3A is a diagram of the preferred ozonator shown in FIG. 2 taken along line 3-3. It is a partial sectional view.

FIG. 4 is a comparison of recycle and waste streams for various pulp processing processes.

Detailed description of the invention The present invention is a method for delignifying and bleaching pulp as well as for the cellulosic portion of wood. minimizes the degree of attack on paper and thus makes it acceptable for the manufacture of paper and various paper products. The present invention relates to a new method for producing products with strength. De-elimination currently disclosed Understand the improvements over prior art provided by the use of agnification and bleaching processes For convenience, some of the steps involved in the delignification/bleaching process are The parameter definitions are shown below.

A. General definition The following definitions are used herein.

“Consistency” is defined as % of the total weight of oven-dried fiber and water. Defined as the amount of valve fibers in the slurry, expressed as: It's also sometimes a bar It is called bu concentration. The consistency of the pulp depends on the operation of the dewatering equipment used. bl 1shers, 1965.862-863 and mAPPI Monog raph No, 27. The Bleaching @ of Pu1l).

Rapsonm collection, The Technical As5ocation f Pu1p and Paper Industry, P963.186 - Based on the definitions found on page 187.

"Low consistency" includes ranges up to 6%, usually 3-5%. that can be pumped by an ordinary centrifugal pump without the use of press rolls. It is a suspension that can be obtained using a decker and a filter.

"Intermediate consistency" is about 6-20%. 15% intermediate consistency It is a dividing point within the range of -. lower than 15% and its consistency can be obtained by a filter. This is bra of pulp mats exiting the vacuum drum filter in the unstock washing and bleaching systems. Consistency. Washers, i.e. brown stock washers or bleaching stages The consistency of the slurry from the washer is 9-15%. Approximately 15% or more A press roll is required for dewatering. Rydholm is a medium states that the normal range of interconsistency is 10-18%; Rapson says it is 9-15%. That sura Lee is special even though it is still in a cohesive liquid phase under some compression at high temperatures. It can be transported by pump using suitable machinery.

"High consistency" is about 20% to about 50%. Lidholm is that normal states that the range is 25-35%, and Lapwan states that the range is 20-35%. %. These consistencies can only be obtained by using a press. can be done. The liquid phase is completely absorbed by the fibers and the pulp is removed at a very short distance. Can be pumped.

Furthermore, "pulping" is used herein in its ordinary sense, and refers to Refers to the cooking of lignocellulosic material to form lignocellulosic material. Pulping is for example , the Kraft process, the Kraft-AQ process and extended delignification forms.

The term “improved kraft process” refers to extended delignification and kraft-AQ As used herein to include all other modified craft methods other than the method.

After all, this method has enjoyed special status and approval in the industry; This is because it is known separately by its name. In addition, oxygen deriging after completion of pulping The ninification step cannot be considered an extended delignification. Rather, we It is the first step in the delignification process to bleach or whiten pulp. I chose to call it.

The degree of completeness of the pulping or bleaching process, i.e. the “degree of delignification” and There are two main types of measurements for measuring the "whiteness" of pulp and pulp. Delignification The degree of bleaching is usually used with respect to the pulping process and the initial bleaching stage. . It is important to note that if a small amount of lignin is present in the bulb, i.e. It tends to be less accurate. The whiteness factor is usually used in connection with the bleaching process. used. What's more, it is because the pulp is slightly colored and its reflective ability is high. This is because it tends to be more accurate in some cases.

There are many methods to measure the degree of delignification, most commonly using the permanganate test. This is a variation of The normal permanganate test is the permanganate value or “KNo.” (This is the 10 minutes consumed by 1 g of oven-dried pulp under certain conditions. is the number of cubic centimeters of 1 normal potassium permanganate solution). .

It is measured by TAPP I standard test T-214.

Furthermore, there are several methods for measuring the whiteness of pulp. This parameter is usually It is a measure of reflectivity, and its value is expressed as a ratio (%) of the scale. usually The method is GE whiteness, which is measured by TAPP I standard method TPD-103. It is expressed as a percentage of the maximum GE whiteness determined.

Furthermore, in appropriate cases, the character codes described in the background art section may be used to describe the invention. Used to represent various stages of pulp processing in the detailed description.

B1 Process steps of the present invention As shown below, the use of the pulping, delignification and bleaching process of the present invention The values obtained from the pulp (i.e., KNo., viscosity and GE whiteness) are to increase the extent of lignin removal and to minimize the resulting degradation of cellulose. This demonstrates the power of this method. After the oxygen delignification process and before whitening, the pulp is , KNo of about 5 to IO1, preferably about 7 to IO for conifers in the United States, It has been partially delignified to about 5 to 7 for hardwoods. this partially The delignified pulp has about 10 or more, generally 13 or more, preferably less than 14 (for softwood valves) or 15 (for hardwoods) It has viscosity. This partially delignified material thus has good strength and and a suitable viscosity, so that it can withstand the action of ozone. Department The partially delignified pulp is exposed to ozone to further delignify the pulp. , thus increasing the KNo of the pulp to about 3-4 for both softwood and hardwood. while increasing the GE whiteness of the pulp by at least about 50-70%. Ru. For conifers, GE whiteness of about 54% or higher is typically obtained, whereas for broadleaf For tree bulbs, values of approximately 63% or more are obtained. Then, the whiteness of the pulp is Refined by alkaline extraction and an additional bleaching step using chlorine dioxide or peroxide. will be increased to

Therefore, for convenience in understanding the present invention, FIG. Figure 1 graphically depicts the various stages used for clarification, delignification and whitening. In Figure 1 As shown, the present invention includes: (a) the process of pulping lignocellulosic material, whereby the pulping chemicals are (b) The pulp can be recovered and reused by methods known in the art. The process of removing chemical residues from the pulping liquor along with residual lignin (usually separated during pulping). (including screening of the pulp to remove unseparated fiber bundles); (C) Pulp alkaline oxygen delignification step (i.e. O or 01); (d ) The partially delignified pulp obtained in step (C) above is washed and treated with acid. Step to remove dissolved organic matter from the raw treatment (screening at this point if necessary) During this period, the effluent from this process may be ): (e) Chelate and acidify the pulp to bind metal ions and adjust the pH to a favorable The process of adjusting to the level: (f) contacting the pulp with ozone to further delignify and partially bleach the material; Step (i.e., Z or Z): (g) Wash the ozonated pulp and reduce the effluent from this process. (also a process of recycling a part to the previous process; (h) caustic alkali extraction and residual lignin (i) cleaning the extracted valve and reducing the amount of effluent; A process in which at least a part of the material is recycled to the previous process; (j) Adding a second bleaching agent (i.e. a step D for brightening and bleaching the bulb) or P); (k) Bleaching with a GIE brightness of about 70-90% by cleaning the bleached bulb. obtaining a product, and (1) Recirculating at least a portion of the effluent from the P bleaching stage to the previous process: or D The effluent from the bleaching stage can be drained into the sewer or after suitable treatment. Process of recycling effluent to previous process Including multi-step methods.

■、Pulping The first step of the method of the invention (in which the amount of lignin removed from the lignocellulosic material is Procedures that minimize the amount of cellulose degradation can be used to improve the It is in the lube process. The particular pulping process used in the method of the invention is the type of gnocellulosic material and more specifically the species of wood used as starting material; It depends a lot on the type. Furthermore, as shown in Figure 1, the The resulting valving fluid may be recovered and reused by methods known in the art. Typically this Following this process, most of the dissolved organic matter and cooking chemicals are removed for circulation and recovery. In addition to cleaning, a screening step is also carried out, in which case The bundle of fibers that the valve passes through the screening equipment and is not separated in pulping remove.

The Kraft method is generally easier to use on all types of wood than other notable methods. forgiven. After all, the final valve obtained from the Kraft method has an acceptable physical Brown stock bulbs are also dark in color due to their natural properties.

Depending on the lignocellulosic starting material, the results obtained with the usual Kraft method can be extended can be enhanced by the use of refined delignification techniques or the Kraft-AQ method. Ru. Furthermore, these techniques can improve the strength and viscosity properties of the valve without detrimentally affecting its strength and viscosity properties. preferred for obtaining the maximum degree of reduction in KNo.

When using the Kraft-AQ method, the amount of anthraquinone in the cooking liquor is in an amount of at least about 0.01% by weight based on the oven dry weight of the wood and amounts of about 0.02 to about 0.1% are generally preferred. craft bar The incorporation of anthraquinone in the oxidation process is detrimental to the desired strength properties of the residual cellulose. contributes significantly to the removal of lignin without affecting it. Also, the addition of anthraquinone The cost of is the cost of chemicals for the subsequent 2m process, E process and D process or P process. partially offset by savings in

Apart from Craft-AQ, or perhaps in addition to Craft-AQ, Kami/ Sands on LAICC method, Beloit RDH method and batch type Guigiester Techniques for extended delignification are used, such as cold blowing.

These techniques also improve pulp production without adversely affecting the desired strength properties of the residual cellulose. gives the ability to remove more lignin during oxidation.

2. Oxygen delignification The next step in the process of the invention is primarily from the brown stock bulbs being treated. Concerning the part of the bleaching process that involves the removal of residual lignin. In the method of the present invention Therefore, this step includes an oxygen delignification step. The solid material removed at this stage is Oxygenated substances, these, like black liquor, are collected, concentrated, and then can be incinerated in an environmentally safe manner in a conventional recovery boiler. Low liquid phase (Tomoichi) The portions are cycled as shown in FIG.

The oxygen delignification process increases the lignin remaining in the brown stock bulb. corresponding unacceptable reduction in valve viscosity It has been found that this can be done in a way that does not cause Generally, that process is verified. The pulping process is performed at low to medium consistency as described below. A brown stock valve is required to ensure uniform application of alkali. amount of alkali required for the oxygen delignification step, then funcystin It is carried out by increasing the sea and delignifying at high consistency sea.

High-consistency delignification is preferred, but low- or medium-consistency delignification is preferred; Inter-consistency oxygen delignification technology enables high-consistency delignification Can be used instead of .

The high-consistency oxygen delignification step is performed in the presence of an aqueous alkaline solution at approximately 2 Valve consistency of 5% to about 35%, more preferably about 27%. It is preferable that This improvement process (0,) is undesirable as previously expected. 45~ which can be removed in a conventional oxygen delignification process without causing a decrease in relative viscosity. At least 60% of residual lignin from brown stock bulb compared to 50% Allows removal of %. Due to the unique process capabilities of this improved process, it clearly constitutes a preferred oxygen process for use in the method of the invention.

The treatment step of the modified oxygen process (0,) is a wood valve, preferably a kraft valve. The unstock valve is substantially uniformly combined with an aqueous alkaline solution while the Maintaining the consistency of the rub at less than about 10%, preferably less than about 5% by weight Including. The alkaline aqueous solution determines the oven dry weight of the brown stock bulb. As a standard, after thickening about 0.5% to about 4% active alkali, more preferably Braun Approximately 2.5% active alcohol after thickening based on the oven dry weight of the stock valve. Preferably, it is present in an amount sufficient to provide the alkali.

This process homogenizes an aqueous alkaline solution into low-consistency brown stock. and virtually all brown stock fibers are uniformly distributed in the alkaline solution. Ensure that the application is exposed. Surprisingly, blocks processed in this way Although round stock valve is not substantially delignified in its processing process, is treated with an alkaline solution at high consistency by commonly used methods. A subsequent high-consistency oxygen delignification process than brown stock Delignification is carried out even more effectively. Al in normal high consistency pulp Local inhomogeneities in the distribution of potash are avoided, thus reducing the associated non-uniform acidity. Eliminates elementary delignification.

This uniform dispensing process thus allows the valve to remain open for at least about 1 minute, preferably about Preferably comprising combining with an aqueous alkaline solution for 15 minutes or less. stomach. Processing times of less than about 1 minute generally provide sufficient time to obtain substantially uniform distribution. On the other hand, processing times longer than about 15 minutes may yield even more substantial benefits. It is expected that this will not happen.

Furthermore, the preferred alkaline treatment of valves according to the invention is carried out over a wide range of temperature conditions. It doesn't matter. According to a preferred practice, the processing steps range from about room temperature to about 66°C (150'C). F More preferred is a temperature in the range of . Atmospheric pressure or elevated pressure may be used. alkaline aqueous solution The process is performed when the be completed. The amount of alkaline aqueous solution present during the treatment process is important for the delignification reaction. It can vary widely depending on the specific process parameters. effective for the purpose of the invention The amount of alkaline solution depends primarily on the degree of delignification desired in the oxygen bleaching step. and on the strength of the particular solution used. The alkaline aqueous solution used is approx. Preferably it comprises a sodium hydroxide solution having a concentration of 20 to about 120 g/l. Yes. This solution is mixed with a valve of low consistency, so that the total mixture is approximately 6.5 to 13.5 g/l, preferably approximately 9 g/l. has. Thus, at these concentrations of alkaline material, temperatures from 49°C (120”F) Bulbs of 3-5% consistency at a temperature of approximately 66°C (150’F) For a 5-15 minute treatment, this uniform distribution of alkaline substances Obtained inside.

According to a preferred embodiment of the invention, the aqueous sodium hydroxide solution Filled to provide about 15% to about 30% by weight of sodium hydroxide on a weight basis. Added to valves of low consistency in small amounts. containing an equivalent amount of sodium hydroxide. other alkaline sources with a quantity, e.g. normal kraft recovery and regeneration cycles. Oxygenated white liquor from can also be used.

Following the low consistency caustic treatment described above, the treated valve cystency increases to a value greater than about 20%, preferably from about 25% to about 35%. be done. Several methods to increase valve consistency, e.g. A method of pressing a material valve and removing liquid from it is effective and known in the industry. It is knowledge.

Oxygen delignification is then carried out at high consistency. gaseous oxygen at high The method of delignification by dissolving in the liquid phase of the valve of cystinsea is an effective method. and is known in the art. Any of these known methods may be used in the present invention. It is considered suitable for However, the oxygen delignification of the present invention is approximately , 6kg/c (80 psig) ~ approx. 7.0 kg/c+n" (100 psig) ) is introduced into the liquid phase of the high consistency pulp while the pulp Preferably, the method includes maintaining the temperature between about 0<0>C and about 130<0>C. high consistency Preferably, the average contact time between the sea pulp and gaseous oxygen is about 20 minutes to about 60 minutes. Delicious.

By following the preferred process of the present invention, the cellulosic portion of the pulp is substantially of the pulp after the oxygen delignification process by at least about 60% without damaging the It is possible to obtain a decrease in KNo-. In comparison, normal oxygen delignification can obtain a reduction in KNo of about 50% before cellulose decomposition occurs. It's only possible. Thus, the preferred process of the present invention differs from the prior art delignification process. at least a 20% increase in delignification compared to the 50% to at least about 60% reduction in KNo. 70% or more Further reductions in cellulose can be obtained with minimal cellulose degradation. pulp cellulose Avoidance of component decomposition is achieved by minimal changes in the viscosity of the pulp treated according to the invention. it is obvious.

After entering the oxygen delignification process, the pulp KNo for special pulp is wood It ranges from about lO to 26 depending on the type of wood (e.g. for kraft pulping , for hardwoods, about 10-14, target 12.5, and for softwoods, about 2. 0 to 24, with a target of 21), while after oxygen delignification, KNo is generally It ranges from about 5 to 10.

A processing arrangement for carrying out the method of the invention is illustrated diagrammatically in FIG. shown there The process described represents a preferred mode of operation that tends to maximize the advantages of the present invention. . Wood chips 2 are introduced into a digester 4, where they are immersed in a liquid, e.g. water. It is cooked in a liquid of sodium oxide and sodium sulfide. The steaming device 4 is a steamer A black liquor 6 is produced which contains a brown stock 8 and the reaction product of lignin solubilization.

The brown stock preferably has a cleaning equipment including a blow tank 10 and a cleaning device 12. The valve is then treated in-situ, where residual liquid contained in the valve is removed. brown strike Many methods for cleaning the rack, e.g. diffusion cleaning, rotary pressure cleaning, horizontal bell Filtering and dilution/extraction are effective and known in the art. These methods are all are within the scope of the present invention. In addition, brown stock screening is a special Most of the undef. 1bered wood is removed for processing. This is often done before or after a cleaning step to remove the dirt.

The washed brown stock is introduced into processing unit 14 where it is treated with alkaline solution and maintained at a consistency of less than about 10%, preferably less than about 5%. dripping The process of the present invention introduces make-up caustic alkali into the treatment stage. It is preferred to include means for maintaining the desired caustic application rate. processed The pulp 18 is advanced to a thickener 20 where the pulp consistency is increased. but, for example, at least about 20% by weight, preferably from about 25% to about 35%. Increased by The removed liquid 22 from the thickening device 20 is further Preferably, it is returned to the cleaning device 12 for use. Produced in thickener 20 The high consistency “pressed” brown stock 24 is deoxidized. proceeded to a gnification reactor 26 where it is contacted with gaseous oxygen 28. Ru. The delignified brown stock 30 is advanced through a blow tank 32. , and then preferably to a second washing device 34 where the pulp is washed with water. to remove dissolved organics and produce a high quality, low color pulp 36. This cleaning process At least a portion of the effluent 38 from the cleaning device 12 is transferred to the cleaning device 12 for use in the cleaning device 12. It is preferable that it be returned to its original position. The effluent 13 from the cleaning device 12 is transferred to a blow tank. 10 or ultimately into the black liquor line 6, either alone or in its entirety if necessary. can be circulated together with part or parts. Also, after oxygen delignification The resulting partially delignified pulp is then subjected to further processing such as mechanical grinding. is screened to remove unseparated fiber bundles from the pulp. It's okay. From here, the pulp 36 is sent to a subsequent bleaching stage where it is fully bleached. products can be produced.

In a particularly preferred method of the invention as shown in FIG. For utilization, kraft pulping of the wood may be carried out, followed by the above-mentioned improvements. low-consistency alkaline treatment/high-consistency oxygen delignification A conversion operation (Ol) may also be performed. Regarding conifers, as mentioned above, this combination The combination has a KNo of about 8 to 10, preferably 9, and a viscosity of greater than about 13 to 14. Produces a pulp with a certain degree of hardness. In addition, the wood was made into a craft AQ valve, and then Conventional oxygen delignification steps (i.e. 0, high consistency alkaline treatment, followed by high-consistency oxygen delignification), which has similar properties. It is possible to obtain pulp. In addition, instead of Kraft AQ pulping, extended a delignification process followed by a conventional oxygen delignification step to It is possible to obtain pulp with the following properties. We also have kraft pulping and extension Delignification process techniques, such as those described in the Background section of this specification. Camino l/MCC process, Beloit RDH process or Sands Combination with cold blow steaming process followed by regular oxygen delignification are effective, but less preferred due to increased cost or process steps. Not.

Any of the various pulping processes and oxygen delignification processes mentioned above before ozone They can be used in combination as long as the KNo and viscosity value of .

Conventional kraft pulping followed by conventional oxygen delignification species of hardwoods (which are relatively easy to delignify and bleach) are generally not acceptable to the present invention. What is this about a given wood species? The combination of these common techniques usually involves the use of large amounts of ozone during the ozonation process. This is because it requires a large amount of cellulose decomposition and is accompanied by a large amount of cellulose decomposition.

With the use of the present invention, ozone consumption can be reduced by several alternative routes, e.g. Conventional kraft cooking followed by an improved oxygen delignification process (0, ), or extended delignification (e.g., Camino y Mcc, Beloit R improved kraft pulping with DH or Sands cold blowing, continuation ) and the usual oxygen delignification process (O) or Kraft AQ steaming (continued). It can be reduced by using a conventional oxygen delignification step (0). Ozone extinguisher This large reduction in costs is due to extended delignification (Camil C, Beloit RD). Improved Kraft Pulping with Masans Cold Blow, Continued L) by the use of an improved oxygen delignification step (0,) or extended Delignification (Kamino CC, Beloit RDH or Sands Cold) Kraft AQ cooking process with blowing) followed by normal oxygen delignification step (0) is obtained in both cases. All of these technologies in one process i.e. extended delignification (Camino l/MCC, Beloit Kraft AQ steaming improved by RDH or Sands Cold Blow); Subsequently using an improved oxygen film IJ genification process (Ol) Further reduce costs. Reduction in ozone consumption generally occurs when pulp viscosity is at an acceptable level. enable it to be maintained.

Using the above high consistency oxygen delignification bleaching step (01) The advantage is that the KNo and viscosity obtained using southern conifers are clearly demonstrated by comparison with related processes under qualitatively similar process conditions. Ru. Conventional kraft pulping operations and conventional high consistency oxygen delignification Using bleaching bleaching, the resulting product bulb typically has a KNo. of about 12 to 14, and and a viscosity of about 15. This KNo. is too large to use the ozone stage of the present invention. subsequent delignification is not possible. However, improvements The use of conventional kraft pulping with high consistency oxygen bleaching In particular, it produces a pulp with a KNo of less than about 9, but the viscosity of the pulp is Approximately over 12-14. This preferred pulp K No. Allows the use of a ganification bleaching stage.

3. Ozone process The next step in the method of the invention is to prepare oxygen delignified brown stock bulbs. ozone delignification and bleaching. This ozonation takes place in an ozone reactor, The reactor is described in more detail below and is shown in FIGS. 2, 3 and 3A. O Prior to the treatment of the pulp with a ozone chemical attack on the cellulose. conditioned. Charge pulp 36 is sent to mixing chamber 40 where it is diluted to consistency. Acids 42, such as sulfuric acid, formic acid, and acetic acid, have low consistency. is added to the pulp of the pulp to adjust the pH of the pulp in the mixing chamber 40 from about 1 to 4, preferably Or it decreases to a range of 2 to 3. pH is adjusted as described above. If anything, It is known that the relative effectiveness of ozone bleaching of pulp depends on the pH of the bulb mixture. This is because it is Low pH has no beneficial effect on the subsequent processing of pulp On the other hand, increasing the pH above about 4-5 lowers the viscosity and resulting in increased ozone consumption.

The acidified pulp is treated with a chelating agent 44 to remove any metals that may be present in the pulp. or complex with metal salts. This chelation process exposes these metals to ozone used in reactors to make them non-reactive or non-hazardous, so that they without causing decomposition, thus reducing the efficiency of lignin removal and also reducing the viscosity of cellulose. No deterioration occurs.

Chelating agents are known per se, for example polycarboxylates and polycarboxylates. Boxylate derivatives such as di-, tri-, and tetra-carboxylates, Including mido, etc. For reasons of cost and effectiveness, this ozone treatment is not preferred. Agents include DTPA, EDTA and oxalic acid. Oven drying valve approx. Amounts of these chelating agents ranging from 0.1% to about 0.2% by weight are generally effective. However, additional amounts may be required if high metal ion concentrations are present. be.

The effectiveness of the ozone bleaching process depends on the pH* levels and metal salts in the bulb as described above. controlled by several interrelated process parameters including quantity. the Another very important parameter is the consistency of the valve during the ozone bleaching step. It is. Bulbs to be bleached must contain sufficient water so that is present as a continuous phase in the individual fibers, i.e. the fibers should be fully saturated with water. It is. The water in the fibers allows the movement of ozone from the gaseous ozone atmosphere. In addition to treating the outer surface of the fiber, perhaps more importantly, ozone also treats the aqueous phase. allows to be moved into the inaccessible interior of individual fibers via Provides a more complete removal of lignin from the fibers. On the other hand, consistency is The solution is diluted and tends to chemically degrade the valve rather than bleaching it. It shouldn't be too low.

The preferred range of consistency (especially for conifers in the southern United States) is about 28 % to about 50%, but the best results were obtained at about 38% to about 45%. It will be done.

Within the above ranges, favorable results indicate that the relative amount of delignification, cellulose degradation obtained as indicated by a relatively low amount and a marked increase in the brightness of the treated pulp. It will be done.

The reaction temperature at which ozone bleaching is carried out is likewise an important controlling factor of the process of the invention. It is. The ozone process reaches a critical temperature (at which temperature the reaction begins and the cellulose It can be carried out effectively at temperatures up to This critical temperature is The particular type of wood used to produce the valve and the history of the valve's previous treatment. It varies considerably depending on. The maximum temperature of the bulb fibers at which the reaction should take place is The temperature at which excessive decomposition of the earth occurs should not be exceeded (this temperature is The maximum temperature for foliage is 49°C to 66°C (120″F - 150′F). Ru.

Ozone gas used in the bleaching process consists of ozone and oxygen and/or inert gas. (or may be used as a mixture of ozone and air) Ru. The amount of ozone that can be successfully incorporated into the process gas depends on the stability of ozone in the gas mixture. Limited by gender. Typically, about 1-18% by weight of ozone is present in the ozone/oxygen mixture. About 1-4% ozone in an ozone gas mixture or an ozone/air mixture containing Ozone gas mixtures containing ozone are suitable for use in the present invention. in ozone gas mixture high concentrations of ozone require the use of relatively small reactors and the equivalent volume of valves to treat enables shorter reaction times, thereby reducing the investment capital required for the equipment. do. However, ozone gas mixtures containing small amounts of ozone are manufactured by They tend to be less expensive and can reduce operating costs.

Yet another controlling factor is the relative weight of ozone used to bleach a given amount of bulbs. It's the amount. This amount is relative to the relative amount of cellulose degradation that can be tolerated during ozone bleaching. The amount of lignin (the amount removed during the ozone bleaching process) that is balanced by can be determined, at least in part. According to a preferred embodiment of the invention, pulp An amount of ozone is used that reacts with approximately 55% to 70% of the lignin present in the 〇The total amount of lignin in the bulb is determined by the KNo. of about 3 to 4 obtained after this step. It is not removed during the ozone bleaching process, as demonstrated by After all, the reaction zone The absence of any ozone in the cellulose causes the ozone to react excessively with the cellulose, This is because the degree of polymerization of cellulose is considerably reduced. In a preferred method of the invention Therefore, the amount of ozone added based on the oven dry weight of the bulb is KNo. 3 to 4. , typically from about 0.2% to about 1%. significant amount of dissolved solids Even larger amounts may be required if present in the system.

The reaction time used in the ozone bleaching process is determined by the complete consumption of ozone used or to the desired rate of completion of the ozone bleaching reaction as indicated by substantially complete consumption. more determined. This time is determined by the concentration of ozone in the ozone gas mixture (relatively (The more concentrated ozone mixture reacts more rapidly) and the ozone mixture that is desired to be removed. varies depending on the relative amount of lignin present. The time required should be less than 2 minutes. is preferred, but the operation can take quite a long time depending on other reaction parameters. It may be necessary.

An important feature of the invention is that the bulb is uniformly bleached. This feature is The zonal gas mixture is completely absorbed into the majority of the fiber flocs (e.g. containing fiber agglomerates). A discrete flow of size of sufficiently small diameter and sufficiently low bulk density to penetrate. Partly obtained by comminution of bulbs into bulk particles. During milling, pulp fibers are separated Complete separation into individual fibers is not feasible. Generally obtained from fine grinding The floc particles consist of a relatively compacted medium surrounded by a plurality of outwardly extending fibers. It has a central core. For purposes of this invention, the floc particle size is defined as this relatively small ( determined to be the minimum diameter of the unfluffed central core. It is determined by measuring what is observed.

The uniformity of bleaching is also highly dependent on the composition of other process parameters. but when the floc particle size is limited to a maximum of 5 an, preferably less than e.g. 3 m The uniform treatment of substantially the majority of these particles, but a small number of poorly colored can be easily obtained, as demonstrated by the observation of bleached floc cores. I found out that I can. If the floc particle size was larger than about 5 an Bleaching can be achieved by It was uneven. Therefore, most of the flocs with respect to their uniform ozonation It is important to obtain sufficient fineness so that the average size is about 51 mm.

Yet another important process parameter is that during the ozone bleaching process, the bleaching The particles are exposed to the access of the ozone gas mixture to the entire surface of the floc and the ozone gas mixture to the entire floc. Ozone bleaching by mixing to allow uniform access of the gas mixture that should be exposed to the mixture. Mixing valve in ozone gas mixture is a stationary bed of flocs (in this case, some of the flocs are (separated from ozone gas and therefore less bleached than other flocs) Compared to the results obtained, this yields superior results in terms of uniformity.

Moving the floc to expose it to the ozone gas mixture resulting in uniform treatment of the blocks. This treatment removes cellulose in fibers including flock. The desired amount of lignin is uniformly removed from the bulb without excessive degradation of the base. bring about The use of controlled particle size and the disturbance during ozonation Adjustment of the ozonation process of the present invention by transfer typically adjusts GE brightness, KNo, and viscosity. It has been found that this results in a final pulp having a variation of less than about 5% in viscosity. To compare , if the process is non-uniform (this is typically a static bed reactor (i.e. particle (such as occurs in unstirred reactors during ozonation), bed formation areas are substantially overbleached, while other areas remain relatively unreacted. Ru.

This is because the flow of the ozone gas mixture in the static bed reactor is not uniform. Ru.

Particularly for comminution of pulp fibers or proper contact between individual fibers and reactant gas stream Treating bulbs with ozone at high consistency without care can lead to fiber defects. Always produces uniform ozone bleaching. This application describes such non-uniform ozone treatment. Represented by the letter “2”. The improved ozone technology of the present invention described above (in this case, the fibers are It is finely pulverized to a size of less than The use of Z) was referred to herein as "Z,".

The valve exiting the ozone reactor has a G E whiteness, which is usually about 55% or higher for softwoods. Bulb (hardwood or coniferous) ) also has a KNo of about 3-4 (target 3.5), and this value I am completely satisfied with the valve at this stage of the process.

An apparatus particularly suitable for ozone bleaching according to the invention is shown in FIGS. 2, 3 and 3A. . As mentioned above, the cleaned valve 36 is sent to the mixing chamber 40 where it is exposed to acid. 42 and a chelating agent 44. Acidified and chelated low consistency Stincy valve 46 is a thickener for removing excess liquid 50 from the valve. 48, for example into a pair of roll presses, where the valve is placed in is increased to the desired level. At least a portion of this excess liquid 50 is transferred to the mixing chamber 40 The remaining portion may be circulated to the blow tank 32. Then get A screw feeder 54 (this is an ozone (acting as a gas seal for the gas) and then a milling device 56, through a fluffer where the valve is predetermined. (which, as mentioned above, should be no larger than approximately 5m). It is pulverized into a Lube fiber flock 60.

The pulverized particles are then transferred to a dynamic ozone reaction chamber 58 (which is shown as (a conveyor 62 moved by a motor 64). Con The bearer 62 is such that the entire surface of the particles is exposed to the ozone gas mixture 66 during the movement of the pulp. for mixing and transporting the valve particles 60 to enable them to become specially designed for. As further shown in Figure 2, the pulp fiber flow after treatment The stock 60 is placed in a dilution tank 68.

FIG. 3 shows the pulp as the pulp particles 60 are conveyed into the reactor by the conveyor 62. 5 is a cross-sectional view of ozone reactor 58 showing the arrangement of particles 60. FIG. Figure 3A is pulverized A paddle-like arrangement is used to move the particles into the reaction chamber 58. 1 is a cross-sectional view of a preferred conveyor for use.

The process in Figure 2 is that the pulp is treated with ozone simultaneously with the ozone gas mixture. shows. However, some of the pulp bleached to the greatest extent also By passing the contained gas in a direction countercurrent to the flow of the pulp 60, a maximum amount of oxygen is achieved. The freshly introduced ozone mixture containing zonate may be contacted first. reaction The pulp that enters the vessel has the highest lignin content and is the first to be Optimal contact with the emitted ozone mixture and thereby actually consuming all the ozone give you the opportunity. This converts ozone from ozone/oxygen or ozone/air mixtures. This is an effective method for strip-pigging.

When ozone 66 is brought into contact with the pulp in a co-current manner as shown in Figure 2 The remaining used ozone gas 70 may be recovered from the dilution tank 68. tank In 68, dilution water 72 (which can also be used as an ozone gas seal) is added. This reduces the consistency of the pulp to a low level for subsequent processing steps. Facilitates movement of bleached pulp 74 therein.

Spent ozone gas 70 from dilution tank 68 is transferred to carrier gas pretreatment stage 7 6, where a carrier gas 78 of oxygen or air is added. This mixture The compound 80 is sent to an ozone generator 82, where an appropriate amount of ozone is generated to produce the desired amount of ozone. Obtain the concentration of The appropriate eggplant/air mixture 66 is then used to delignify the pulp. is sent to an ozone reactor 58 for oxidation and bleaching.

After completion of the ozone bleaching process, the substantially delignified pulp 74 is shown in FIG. Less of the water 86 is thoroughly washed again in the washer 84 as shown and recovered. A portion of both is recycled to the process's cleaning equipment 34 and thereby flushed to the sewer. Significant environmental benefits result from the elimination of liquids.

The bleached low consistency pulp 74 after ozonation has a reduced amount of gunin and hence low KNo and acceptable viscosity. K obtained No.

and the exact value of viscosity depends on the particular treatment that the pulp has undergone. For example, normal Kraft pulped and first improved high consistency oxygen deriging delignified by nylation (0,), followed by ozone, preferably modified Coniferous pulp from the southern United States that is further delignified by uniform ozonation (Z,) The plastic typically has a KNo of about 3-4 and a viscosity of about 10. Craft AQ High consistency oxygen bleaching subjected to pulping and then improved (01) Conifers in the southern United States subjected to a modified homogeneous ozonation treatment (Z,) Typically has a KNo of about 2 and a viscosity greater than about 12.

The resulting pulp 74 is significantly whiter than the starting pulp. For example, in the south Softwood has a GE whiteness of about 15% to 25% after the pulping process and oxygen bleaching. It has a GE brightness of about 25% to 45% after white and after ozone bleaching process. It has a GE whiteness of about 50% to 70%.

4. Alkaline extraction The washed pulp 88 from the ozone stage is then transferred to an extraction vessel for performing extraction. In 92 a sufficient amount of alkaline material 90 is combined. In this way, pulp 88 In the vessel 92, an agent is added which solubilizes a significant portion of the lignin remaining in the bulb. determined in advance over a predetermined period of time that correlates with the amount of exposed to an aqueous alkaline solution at a controlled temperature. This extraction process also The whiteness of the sample is increased by typically about 2 points of GE whiteness. After that, The alkaline-treated pulp 94 is sent to a washing device 96, where an alkaline aqueous solution is The pulp is washed from the pulp to remove substantially all of the decomposed lignin from the pulp. , thus producing a substantially lignin-free pulp. This process is carried out by those skilled in the art. is well known in the art and does not seem to require further comment here. The example is The preferred extraction parameters for this step of the process are described. Alkali recovered At least a portion of solution 98 is circulated to cleaning device 84 . Again, important environmental Benefits result from the elimination of sewage discharges with this solution.

If high final brightness is targeted, the extraction step may be performed by can be enhanced by incorporating (E,) into the caustic extraction process. This alternative method are also known to those skilled in the art and require no further comment here.

5. Additional bleaching step For most papermaking purposes, a final whiteness in the range of 50-65 is insufficient. subordinate Therefore, in order to further increase the GE whiteness to a more desirable range of about 70-95%, The pulp is subjected to brightening bleaching, which mainly produces color from the lignin remaining in the pulp. The purpose is to convert the group group into a colorless state.

After the pulp is extracted and washed again, it is ozone bleached and the extracted pulp is bleached. White can be achieved using various substances. As shown in Figure 2, the washed pulp Bleach 100 is combined with a selected bleaching agent 102 in a bleach container 104. Like A good bleaching agent is chlorine dioxide or peroxide. After bleaching, the pulp 106 is washed The effluent is washed with water 114 in the device 108 and recycled 110 or to sewage treatment. If the wash water stream 110 is circulated 112°, at least a portion of the wash water flow 110 is It is sent to station 96.

The resulting bleach bulb can then be recovered and used in a variety of applications.

One of the principal substances traditionally used and generally highly effective is chlorine dioxide (D). (See Figure 1). According to the present invention, a suitable amount of chlorine dioxide is about 80 It is possible to obtain high-strength pulps with GE brightness greater than %.

Pulp entering the chlorine dioxide stage is relatively low in lignin, so chlorine dioxide enrichment bleaching White contains only about 0.25% to about 1% based on the oven dry weight of the pulp. It can be carried out in the presence of chlorine dioxide.

The chlorine dioxide used in the whitening process is produced by a process that does not contain elemental chlorine. Preferably, it is prepared. However, there is also a less preferred, minimal A comparison of the amount of chlorine dioxide containing elemental chlorine present in ozone bleached pulp Due to the small amount of lignin, there is little increase in the relative amount of undesirable contaminants. Can be used in If chlorine dioxide is used, the effluent from the final bleaching step of the invention The amount of material is extremely small and can be safely ejected as shown in FIG.

However, the discharge of effluent from the final chlorine dioxide bleaching step into the sewage system is not allowed. In some cases, the stream can be further refined by being treated with a membrane filtration process such as reverse osmosis. It can be manufactured. This technique can be recycled back to the previous bleaching stage for further use. Gives a clear filtrate. This has the advantage of reducing the use of fresh water. Furthermore , the concentrated chloride stream obtained from membrane filtration is relatively small in volume.

Very high bulb brightness, e.g. 92-95% GEB, may be desired. Additional bleaching steps may be required in such cases. Additional extraction and chlorine dioxide treatment are common choices, thereby reducing the O, Z, EDED bleaching order. occurs.

Instead of using chlorine dioxide for final brightening, brightening bleaching is also shown in Figure 1. As shown, it may be done with hydrogen peroxide. This technology is completely chlorine-free. give a fast bleach cycle (e.g. O,L EP sequence), in which case the chlorinated The substance is not produced in the bleaching process and the liquid extraction product requires tedious filtration techniques. It can be easily circulated without having to do so. However, using peroxide as a bleaching agent In case, KNo of pulp from softwood or hardwood, after peroxide bleaching step As the final product of In order to obtain pulp, it should be reduced to a level of about 6 before the ozonation step . This is because peroxide is not effective in bleaching chlorine dioxide. death However, if a completely chlorine/chlorine dioxide-free process is desired, Oxides give acceptable results.

Typical peroxide brighteners and their use in this process are conventional and within the skill of the art. Those skilled in the art are aware of the appropriate concentrations, types and uses of such peroxides. peroxide water Plain is preferred.

The washed and further whitened pulp is about 70-95%, preferably about 80-95% % GE whiteness. In addition, the physical properties of this pulp are similar to that of ordinary CHDEC. Obtained by pulp produced by process or DC/DECC/superior It is equivalent to a rational property.

6. Circulation of cleaning effluent In any valve process, filtrate treatment determines the overall economics of process operation. is an important factor in terms of performance or cost. The water used in the process is from a suitable source requires both access to and treatment of the effluent before discharge.

in an effort to reduce the water demands of the process. It is desirable to circulate. This practice uses chlorine or multi-step chlorine dioxide. It cannot be used in processes that What is generated by these processes? effluents containing large amounts of chloride produced by by-products of such chemicals. It is. The circulation of these effluents thus causes the accumulation of chloride, which in turn Resulting in corrosion of processing equipment or use of expensive construction materials. In addition, such a cycle Effluents require significant treatment before these effluents can be discharged from the plant. , thus requiring additional expenditure in terms of equipment and processing chemicals.

As shown in Figure 4, the conventional CEDED process or QC/DEffl technique The use resulted from the cleaning process due to the large amount of chlorine-containing compounds found in it. Creates significant disposal problems for spills. As mentioned above, these flows are circular. It is preferable that the material cannot be recycled and is treated before being discharged into the environment. Effluent circulation is water The treatment equipment can then be used to reduce the amount used, but then the treatment equipment may experience increased corrosion rates due to the amount of chloride added.

However, in contrast, the use of the O,Z,ED process of the present invention Resulting in the formation of only minimal amounts of chlorinated material, this water can be safely drained and immediately disposed of. It can be discharged into sewage systems within most environmental protection standards. Additionally, this spill can be further cleaned. clean filtrate (as indicated for subsequent use without accumulating chloride) may be processed by reverse osmosis to obtain (which may be recycled to the previous bleaching stage). D floating If a white stage is desired, processes are employed to reduce the demand for chlorine dioxide. Sometimes. The E0 process allows the pulp to obtain a high level of whiteness, but The use of sodium hydroxide and oxygen in this process requires additional expense. It will be done. Also, industrial operations for preparing chlorine dioxide are known, and the amount of residual chlorine is minimized (e.g. R8 process versus R3 process). ).

These reduced chlorine chemicals reduce the amount of chloride in wash water effluents. It is preferably used in the D stage.

0.2 of the present invention instead of 0, Z, ED. Chlorinated using BP process An additional significant advantage over the prior art is that no chemical compounds are produced. I can do it. This means that all effluents are free from chloride build-up in the process wash water stream. can be cycled without any problems.

Therefore, the process of the present invention can reduce the volume, color, COD, BOD and salt of the effluent. This results in considerable advantages with respect to the reduction of organic matter that is dilated. Furthermore, it is used in the cleaning process. effluents were significantly reduced compared to prior art processes using chlorine. Washing equipment vents contain chloride and require treatment before discharge. does not carry chemically modified organic compounds or gases.

Example The scope of the invention is further illustrated with respect to the following examples. These examples are They are provided for illustrative purposes only and should not be construed as limiting the scope of the invention in any way. It shouldn't be. Unless otherwise noted, all chemical percentages are oven dried. (OD) is calculated based on the weight of the fiber. Also, those skilled in the art can determine the target whiteness I understand that the value of does not have to be exact. What happens is ± from the target. This is because a GEB value of 2% is acceptable. All with D stage except for example 11 In this example, it is known to contain a 6:1 ratio of chlorine dioxide to elemental chlorine. R-3 type chlorine dioxide solution was used.

Example 1 (comparative example) Loblolly pine chips were steamed in an experimental batch mode according to the conditions in Table 1 and then cooked in a conventional cooking method. Raft pulp was produced. The obtained pulp has a KNo of 22.6 and 27.1c. It had a viscosity of ps. The kraft pulp was then subjected to regular oxygen treatment (Table 2 and Table 5) followed by normal QC/DEC order (Table 3) and OZ, ED bleaching order bleach to a final target brightness of 83 GEB using both Ta. The ozone bleaching step consists of 35% consistency with 0.61% ozone application. I went by sea.

Conditions for making loblolly pine kraft pulp Conditions/process parameters Press team time (minutes) 2.5 Time to reach a temperature of 175℃: 1 hour Time at 175℃ temperature: 1 hour Liquid:wood ratio 4:1 Sulfide month C (%) 25.8 Active alkali (%) 17.4 %AA O, 43 Viscosity (cp) from Black Liquor Fill Pack (FILLBACK) s) 27.1 Table 2 Typical normal O-stage bleaching conditions for pine pressure (PSIG) Chemical % pl Temperature (℃) Pulp consistency (%) 80 2.5NaOH10,211027゜*Both alkali addition and oxygen delignification Process Chemical % pH Temperature ('C) Pulp consistency (%) C/D 3. 6CI! 1.8 50 3.150.6C1Oz E 1.5NaOH11,67012 Process Chemical % pH Temperature (0C) Pulp consistency (%) Acidic up to pH 2 2 22 3-4 (H2SOO Chelation 0.11 2 22 3-4” 2 three 2! Σ-11111--- ------ (Ozone) 0.2-12-422 35-45E 1.5NaOH11,5TO 12 111 and 111 and 11 and 11 and 11 and 11 and 12 and 11 and 11 and 12 and 11 and 11 and As shown in Table 7, OZ, ED bleaching under these conditions (with a target of 83%) 15 with acceptable strength properties compared to GE Brightness QC/DED reference pulp. caused a loop. Under these conditions, OZ-ED/<ru is 9. Limitations of Taps It had a viscosity of 0.

OZ, whose strength properties are applied at the final stage is 2.5%! ED/Z/Repunitsu (Measured 1.

The target brightness was achieved only with an excess of chlorine dioxide. salt dioxide The high whiteness of OZ and E pulps, which are suitable for raw processing, makes it possible to apply the oven by a factor of 1. This (the viscosity of the velvet and (strength force) causes a certain amount of loss.

1 animal, 1 ml, 1 or above O7, ED QC/DBD □ C3F “Tear rupture CSF” Tear rupture 646 205 6.54 659 228 5.85508 142 g, 46 492 147 8.4 9351 145 8.81 334 126 8.50 *Canadian standard filtered charcoal Table 7 Pine Craft OZ, ED Whiteness Response-Comparison 6)--111-------- This resulted in a pulp with ------- content.

Boiling Loblolly pine craft/AQ pulping conditions 1-/Ii-111111-2 Press team time (minutes) 2.5 Time to reach a temperature of 175℃: 1 hour Time at 175℃ temperature: 1 hour Liquid to wood ratio 4:1 Sulfur month [(%) 25.3 Active alkali (%) 18.0 %AA from black liquor film pack 0.43 AQ% on wood 0.025 target white using the normal QC/DEC order and OZ=ED order such that It was further bleached with 83% GEB i. The use of Kraft AQ pulping technology A starting point of low KNo, with acceptable viscosity properties for the bleaching stage (lube made Achieved the goal of building. 3 ozone bleaching steps with 0.35% ozone application Using row G ball with 5% consistency and 166% Cl0z in the final stage. The target whiteness was achieved.

As shown in Tables 9 and 10 below, the final chlorine dioxide stage Optical properties measured by degree response have been improved, and intensity properties have been improved to meet QC/DED standards. It was acceptable in comparison.

Pine Craft/AQ Comparison of properties of QC/DED and O7, ED QC/DED OL ED CSF tear rupture C3F tear rupture factor length factor length 658 194 6.02 650 194 6.29524 139 8.1 4 497 159 7.83352 128 8.92 334 130 8 J4190 119 8.74 211 121 8.59 Table 10 Matsu no Craft/AQ OZ, HD whiteness response whiteness 52.9 76.8 80.7 g3.283.483.8 (GEB%) Example 3 (comparative example) Craft brown stock of pine with KNo. of about 24, about 30-36 weight % of consistency/cysticity to produce a high consistency mat. . Approximately 2.5% brown stock matte based on the dry weight of the bulb. of 10% sodium hydroxide solution to yield It was foggy. Add a sufficient amount of dilution water to reduce the brown-kari/tsuku mat to about 27% The temperature was adjusted to Next is high consistency brown stock mackerel. - Soto was subjected to monooxygen delignification using the following conditions. 110℃, 30 minutes , 5.6kg1011″ (801) S iH) 0..

Example 4 The pine kraft brown stock from Example 3 is based on oven-dried Nokulup. Add enough volume of 10% NaOH solution to make 3 days of NaOH addition. It was introduced into the processing container at the same time. Add sufficient dilution water to obtain approximately 3% by weight of chlorine in the processing vessel. Obtained round stock consistency. Brown stock and sodium hydroxide The aqueous solution was uniformly mixed at room temperature using a ribbon mixer for about 15 minutes. Then, The treated brown stock was pressed to a consistency of approximately 27% by weight. . After pressing, the sodium hydroxide in the fibers is only equal to about 2.5% as in Example 3. It was. The treated brownstock was then subjected to oxygen delignification as described in Example 3. Delignification was performed according to the procedure. A comparison is shown in Table 11.

KNo. 13 9 Viscosity (cps) 14.8 14.0 As can be seen from the comparison of Examples 3 and 4, alkali addition of low consistency followed by A preferred method of the invention using high consistency oxygen treatment (0yo) is Greater delignification than prior art methods with little change in strength properties The result was bleached brown stock with a 100% white color.

As a result of the low KNo. valves produced by this process, subsequent bleaching The process can be adjusted to produce a pulp containing less lignin with high brightness. child Thus, the bleaching step of such bulbs is more effective than pulp not treated according to the invention. Also requires less bleach or shorter bleaching time.

Example 5 0 of Example 4 of the present invention. Valve made from pine by process (0) (i.e., without using a low-consistency alkaline treatment step) Compare with Lube. High consistency oxygen deriging of brown stock pulp - The average caustic dosage for carbonization is 4 per ton oven-dried. It was found to be 5 pounds per ton or 2.3%. At that amount, oxygen The average KNo-low F per delignification reactor was 10 units. Like For the same amount of caustic applied to the pulp by a new treatment process, delignification The average KNo during conversion was 13 units, a 30% improvement compared to the normal process. It turned out to be good.

We also demonstrate this advantage in selectivity of delignification by comparing bulb viscosities. be able to. The average KNo and viscosity for normal valves are 12 and ■ and 14.4 cps. Regarding the preferred treatment process of the present invention, substantially The average KNo at the same viscosity (14.0 cps) was 8.3.

In addition, the selectivity of delignification was improved using a processing valve comparable to a brown stock valve. can be expressed as the change in viscosity between KNo. oxygen delignification The selectivity of conversion is quite rapid when the change in KNo starts to exceed 1 OKNo descend. The decrease in selectivity is due to the rapid change in viscosity for a given change in I<No. observed as a significant increase. For example, for a change in KNo in units of 1 g, the viscosity changes. The corresponding change is expected to be 12 to +3 cps. In contrast, the preferred method The same of KNo, obtained by delignified valve treated using The change in viscosity was found to be approximately 6 cps for each gram change (in units of 1 g).

The change in viscosity per change in KNo. For the valve obtained by is clear. The results are shown in Table 12.

KNo. 21.9 20.5 Viscosity (CpS) 21.5 20.5 KNo. / viscosity ratio 1.02 1.0 Oxygen delignification stage valve KNo. 12.1 8.3 Viscosity (cps) 14.4 14.0 KNo./viscosity ratio 0.84 0.59 Caustic alkali, lb/ton 39 ．． 4 46.0 Delignification (%) 44.7 59.5 K Combining southern pine bulb with the uniform alkaline treatment described in Examples 4 and 5 The improved oxygen delignification process (0,) with the conditions in Table 2 and the Using the conditions shown in Table 13 below, the operating 600 TPD fin epaper) was manufactured on-site. O-stage parts produced by this new method A bleaching process using ozone as described in an embodiment of the present invention It had the qualities needed for successful completion. Oxygen stage valve is 7.9 KNo. (compare with a typical normal O-stage KNo. of about 12). ). The viscosity of the delignified bulb was 15 cps and the improved oxygen was hardly reduced due to the high degree of delignification obtained with the use of . This valve is then subjected to any of the many process embodiments described herein. Further bleaching using either of the We were able to produce a bu.

C/DED bleaching of this bulb was completed in the laboratory as described in Table 14. and obtained a standard for comparison of properties.

Process OD woven fiber used pH temperature Valved chemicals (%) (℃) Consys Chinshi (%) treatment 30% -223-4 (NaOH) Oxygen (Oz) 80 psig 10.2 110 27 Table 14 C/D 2.4 C1g 1.8 50 3.150.4C10z E 1.05NaOH11,57012D 0.23C1Oz 4.2 60 12 The ozone bleaching step is carried out in a pilot plant reactor as shown in Figure 2. It was. The operating conditions of the pilot plant reactor are shown in Table 15.

Gas flow and valve flow parallel flow Operation speed 6.50D TPD” Gas flow rate 58 scfm Valve consistency 42% Ozone application (Note: Niosin 1.18%) Contains dissolved solids that consume Ozone is used because of the valve (increased dose) Valve residence time 1 minute 2. Stage KNo. 3.9 Z, step viscosity 11.8 cps The ozone bleached bulbs produced in the pilot plant reactor are then treated in the laboratory with an extraction step and a chlorine dioxide step as described in Table 5 of A final bleach bulb was produced with the target brightness. Only 1.0% of CIO□ final A stage preparation was used for the fibers.

The strength and optical properties of ozone bleached bulbs are compared to conventional QC/DED standards. The results of the comparison are shown in Tables 16 and 17 below.

C3F tear rupture CSF tear rupture factor length factor length 656 147 6.80 659 177 5.57511 113 8.0 0 510 146.6.93335 96 8.69 367 111' 7 ．． 90CIO! (%) 0 0.5 1.0 Whiteness (GEB%) 55.0 70.0 84.2 Example 7 of the practicality and applicability of the method of the invention! 1! To further illustrate the scope, mainly rubber Southern hardwood fibers from mixed hardwoods, including Bleached with ozone in the Ilot plant. Normally manufactured at 6007PD factory The oxygen stage valve was treated with ozone in the pilot plant reactor. Oxygen stage bar The lube had a KNo of 5.7 and a viscosity of 14.1.

Comparison of final bleaching of a portion of stage 0 pulp by conventional C/DED sequence in the laboratory. Obtained standards for. Table 18 shows the C/DED conditions.

For blue Process Chemical (%) pH Temperature (℃) Valve consistency (%) C/D 1.6 I C1z 1.8 50 3.150.26 ciot E 1.0NaOH11,97012 D 0.3Σ animals 10.　43=”West-11111 Ward-----Oshin The treatment conditions of the reactor are shown in Table 19. Next/Guilot Plant Z1 stage bar to the target whiteness using normal E and D stages as shown in Table 20. Finally bleached. Only 0.35% D-stage CIO□ preparation 00/(/Rep [ Used for two. The strength and whiteness properties are as shown in Table 21 and Table 22. It was acceptable compared to the standard.

hunger Hardwood Pilot Plant Reactor Operating Conditions Operating Parameters Values or Conditions Gas flow and valve flow parallel flow Operation speed 900 TPD Gas flow rate 60 scfm Pulp consistency 36% Ozone applied (note, ozone 0.86% Contains dissolved solids that consume Ozone is used because of the valve (increased dose) Valve residence time 1 minute Z1 stage KNo, 2.5 z1 stage viscosity 11.9cps Z1 stage whiteness 63%GBB Table 20 E 1.0NaOH12,07012 C3F tear rupture C3F tear rupture factor length factor length 526 89.9 4.41 515 88.3 4.52399 87.2 5.71 419 82.0 5.65262 79.5 6.26 293 70.5 6.56 A comparative test similar to Example 5 was carried out using a mixture containing mainly rubber and oak. We followed a kraft hardwood valve manufactured in the laboratory from leafwood. Improved again Considerable information regarding the oxygen delignification reactor using the oxygen process (0,) It was found that a large decrease in KNo was obtained compared to normal oxygen treatment (0). . The average caustic alkali dosage for hardwoods is 27 lb/ton, or 1. It was 4%. This resulted in a drop in KNo of approximately 5 units during the oxygen step. present invention For the same amount of caustic used by the improved oxygen process of ca. ．． An average KNo. reduction of 3 units was obtained, which was an increase of approximately 50%.

This advantage of selectivity in delignification is also shown by comparing bulb viscosities. be able to. The average hardwood KNo and viscosity are 7.6 and 16 cps, respectively. It turned out to be. For the present invention, a KNo of 6 and a viscosity of 17.7 were obtained. It was done. In addition, the KNo at the same viscosity (16 cps) as the untreated valve is 5. ．． It turned out to be 8.

Additionally, the selectivity of delignification was improved, comparable to the brown stock valve. The change in viscosity between the oxygen-treated pulp and the change in KNo, can be expressed in terms of the change in KNo. .

When comparing valves treated with conventional oxygen to valves of the present invention, increased delignification was observed. There is a large decrease in the selectivity of delignification with respect to increased extent. 4 units of KN With respect to the change in o, the average change in viscosity is It was 4 cps for lube. In contrast, produced by a modified oxygen method For the same valve, the change in KNo. for the same change in viscosity was 7 units. Escape Expressed in terms of the selectivity ratio of lignification, the selectivity for the improved method is 1.8 KN o, /cps, and the selectivity for normal processes is IKNo, /cp s, which was an 80% increase. The results are shown in Table 23.

KNo. 12.3 13.0 Viscosity (cps) 21.6 23.4 KNo. / viscosity ratio 0.57 0.56 Oxygen delignification stage valve KNo. 7.6 6.0 Viscosity (cps) 16.0 17°7 KNo./viscosity ratio 0.47 0.33 Caustic alkali, lb/ton 27 ．． 6 26.4 Delignification (%) 38.0 54.0 General A series of experiments were carried out from a 600 TPD tissue paper mill at a normal oxygen delignification stage (0). The test was carried out in a pilot plant using a valve of These experiments This was done to demonstrate the effect of pH on the ozone bleaching process using leafwood. anti The operating conditions of the reactor were kept constant as shown in Table 24, and the pH of the ozone stage was maintained constant. It was the first variable.

Qingsei Typical Operating Conditions Operating Parameters Values for Hardwood Pilot Plant Reactors or conditions Gas flow and valve flow parallel flow Operation speed 90D TPD Gas flow rate 40 scfm Valve consistency 40% Ozone applied (Note: Niosin 1%) Contains dissolved solids that consume Ozone is used because of the valve (increased dose) Pulp residence time 1 minute As can be seen from Table 25 below, the effect of pt (on ozone bleaching process is low). It is important in pH and beneficially improves the selectivity of the bleaching process.

Z, change in KNo in stage -2,79-3,17-3,16-3,67 Z, change in whiteness (GEB) in stage +12.1 +15.0 +11 ．． 7 +17.4z Change in viscosity (cps) in 1 stage -6,0-7,1 -4,9=4.4 cases l0 Benefits of producing fully bleached pulp using the 0Z, ED process The nature of some comparisons is important to show the effects. Typical operating data and Effluent measurements were performed using CHDEC bleaching sequence and OC/DED bleaching for southern pines. Collected from operating factory using order. These properties were compared to the OZ prepared in Example 1, Effluent produced by OZ-ED sequence using ED Pabal and effluent Compared with the nature. See Table 26 for normal CEDED order. normal See Tables 2 and 3 above for QC/DED order. Also, OZ, See Tables 4 and 5 above for ED order. CEDEC order effluent is the combined C-Et, DI, Et, and so on.

It should be noted that the effluent of QC/DED effluent is C/D, E and D combined effluent, OZ, ED effluent is D stage effluent , each exhibiting some effluent properties. As shown in Table 27 below, The ozone bleaching sequence substantially reduces the environmental impact of the effluent from the bleaching process. Ru. EPA method 110.2 was used to measure coloration. From this data, The present invention applies to colored materials of less than about 2 pounds/ton, BOD5 values of less than about 2 pounds/ton, and and a total organic chloride amount of less than about 2, preferably less than about 0.8. I know how to give.

C5,3CI□ 4.10 40 3.15E 3.25 NaOH11,37 012D ICIO236012 E　O,6NaOH11,6701,2Table 27 BOD, (1 bond/ton) 34 21 1 colored material (1 bond/ton) 367 83 Less than 1 Southern pine kraft pulp was processed through three modifications of the basic 0ZED order. Bleached using good quality. In the first order (O2, IED) the pulp is usually of oxygen, improved ozone, caustic extraction and ctot/CI□ ratio 6:1 Bleaching was performed using chlorine dioxide prepared in the R-3 order as shown in Tables 4 and 5.

In the second sequence, again using the improved oxygen process (0,), the final stage For the floor, R-3 type chlorine dioxide was used.

In the third sequence, the modified oxygen process (01) is used again and the final R-8 chlorine dioxide solution was used in the step at a ratio of 95:l. Table 28 has been improved Figure 2 shows the significant environmental impact caused by the use of oxygen processes (0,). Also , R-8 bleach had a significant effect.

C1oz/C1t ratio at the final stage 6:1 6:1 95:ITOCI , Pound/Ton 0.8 0.3 0.2 Penalty U The pulp of the southern data pine was processed using the Kraft method and the methods described in Tables 1 and 8 above. Prepared by Kraft/AQ pulping process. Furthermore, these pulps, e.g. Conventional oxygen delignification and modified oxygen delignification as described in Example 4 and Example 5. The effectiveness of combining these processes on the ozone bleaching sequence (Regarding prolonging delignification with minimal impact on pulp strength) ) was shown. As can be easily seen from Table 29, these processes have a cumulative effect. produce fruit. Extremely low O, Z, E, KNo, with almost no effect on final viscosity. can be reached. Conversely, for previously described ozone bleaching processes about 3 ．． The amount of ozone required to reach the targets of O, Z, E, KNo. can be significantly reduced. In addition, the cumulative effect is very low 0-IZ -E KNo, if required for the functional peroxide stage, O, Z, B The P process produces a southern pine pulp that can be fully bleached.

Parameters Craft + 0 Craft/AQ+ Craft/AQ + (Conventional technique Technique) 0 0゜ 0.5% ozone in each case application of KNo. 6.2 3.4 1.8 At the target KNo of viscosity (cps) 12.1 11 10.13.5 Properties and ozone application Ozone (%) 1.0 0.5 0.29 Coniferous trees in the south, namely data pines, are shown in the table. 26 and as shown in Tables 2 and 3 above. 02.02 using the normal QC/DED sequence and shown in Tables 4 and 5 above. Bleached to a target brightness of 83GEH using EDIllN sequence. wood-based Dirt was purified and 0.75% by weight '02. ED departure brown Added to stock to remove dirt compared to CEDED bleach and QC/DED bleach We investigated the ability of this order. Effective black area Area), the soil properties of these sequences measured as bark and binding fibers are the same. etc.

Next This example illustrates the range of applicability of the ozone bleaching process of the present invention. bleached pulp, A wide range of products can be whitened using the appropriate combination of ozone and chlorine dioxide charges. Can be manufactured across a wide range of colors to minimize environmental impact and operating costs. Ru. Products with whiteness greater than or equal to 65% GEB as shown in Table 30 below , various combinations of ozone and chlorine dioxide while retaining their strength properties. It can be manufactured by

Process Chemicals pH Temperature Time Pulp GEB KNo, Viscosity 0 (%) (℃) ( minutes) Consistency (%) (%) (40ml) (cps) 0, [Table 13 Conditions shown] 40 8.5 12.5L O, 432221, 5435O- 10E 1.5 11.570 60 12 --- 9.8D 0.5 4-5 70 180 12 65-9.60, 7 70 9.6 *0. The post-stage viscosity value is an interpolated value based on established data.

It is clear that the invention disclosed herein is well adapted to meet the above objectives. It is understood that many modifications and embodiments will occur to those skilled in the art. and the following claims cover such modifications and embodiments as are within the true spirit and scope of the invention. It is intended to include all persons.

Procedural amendment Heisei Year Month Day

Claims (1)

[Claims] 1. Chemically digesting lignocellulosic material to obtain pulp; deriging the pulp with oxygen lignin to remove a significant portion of the lignin; a combination of chemical cooking and oxygen delignification processes is selected to contain a specific amount of lignin and have a specific viscosity. and the consistency and pH of the intermediate pulp are determined in advance. The intermediate pulp is adjusted to Discontinuities of size and density low enough to have a sufficiently small diameter to facilitate penetration. pulverizing the discrete particles into continuous particles and mixing the discrete particles in intimate contact with ozone at a sufficient temperature for a sufficient time to obtain substantially uniform delignification and bleaching in the majority of the particles. The intermediate pulp is ozone delignified by bleaching the particles with sufficient ozone to remove a significant portion, but not all, of the lignin. a certain amount of lignin in the intermediate pulp is such that the bleached pulp reaches a certain GE brightness after ozone delignification; A certain GE brightness and a certain viscosity characterized in that the viscosity is high enough to offset the viscosity reduction during ozone delignification, thus allowing the bleached pulp to reach a certain strength. A method for producing bleached pulp having a certain strength as shown in 2. The method of claim 1, wherein the pulp particles have a size less than about 51 mm. 3. The method of claim 1 or 2, comprising chemically digesting the lignocellulosic material by kraft pulping, kraft AQ pulping or extended delignification. 4. Oxygen delignification process produces low to intermediate consistency performance. a low to medium consistency pulp with an aqueous solution of an alkaline substance; treatment at a predetermined temperature for a predetermined period of time related to the amount of alkaline material that causes the potash material to be distributed substantially uniformly; the consistency of the pulp is increased to a high consistency; and the resulting high consistency pulp is high con Claims comprising subjecting the consistency to oxygen delignification to obtain an intermediate pulp. The method described in box 1. 5. K No. of intermediate pulps having a GE brightness of at least about 50%, a viscosity at a strength of greater than about 10 cps, and a specific amount of lignin of about 10 or less. 2. The method of claim 1, wherein the specific viscosity is greater than about 13 cps. 6. an intermediate pulp in which the lignocellulosic material is softwood, a GE brightness is at least about 50%, a viscosity at a strength is greater than about 10 cps, and a specified amount of lignin is about 7 to 10 cps; KNo. 2. The method of claim 1, wherein the specific viscosity is greater than about 13 cps. 7. an intermediate pulp in which the lignocellulosic material is hardwood, a GE whiteness is at least about 55%, a viscosity at a strength is greater than about 10 cps, and a specified amount of lignin is about 5 to 8; KNo. 2. The method of claim 1, wherein the specific viscosity is greater than about 13 cps. 8. The KNo. of the bleached pulp is such that the amount of lignin contained in the pulp after ozone delignification is approximately 3 to 4. The method according to claim 5, 6 or 7. 9. 2. The method of claim 1, further comprising bleaching the pulp after ozone delignification with a brightener to increase the GE whiteness of the bleached pulp. 10. The bleached pulp is treated with a pre-preparation method that correlates with the amount of alkaline material being combined. bleaching agent in combination with an effective amount of alkaline material in an aqueous alkaline solution at a temperature determined by solubilizing a significant portion of the lignin remaining in the pulp; then removing substantially all of the solubilized lignin from the aqueous alkaline solution and producing an extracted pulp prior to bleaching with a brightener. It is further recommended to extract part of the alkaline aqueous solution as follows: 9. The method according to claim 9. 11. 10. The method of claim 9, wherein the brightener is chlorine dioxide or peroxide. 12. The lignocellulosic material is digested to produce No. 1 KNo. and the first viscosity value. delignifying said pulp with oxygen to produce said first KNo. Lower 2nd KN o. (This value indicates that the partially delignified pulp Most of the cellulose components of the nitrated pulp are chemically separated by oxygen delignification. further delignification with ozone while maintaining viscosity at previously unknown levels. partially delignified polymers with sufficient and applying a sufficient amount of ozone to the partially delignified pulp for a sufficient period of time that is correlated to the amount of ozone applied to said partially delignified pulp. Further delignification of partially delignified pulp by applying The process maintains viscosity while aggressively chemically attacking the cellulose components of the pulp. Partially deliminated as described above, avoiding a substantial reduction in the strength of the pulp without food consumption. The second K No. of the agnized pulp. The third KNo. was significantly lower than that of the third KNo. and a GB white that is substantially higher than the GE whiteness of the partially delignified pulp. Lignocell into a pulp having a certain strength as indicated by a certain G E brightness and a certain viscosity, characterized by obtaining a substantially delignified pulp with A method for delignifying and bleaching loin material. 13. The partially delignified pulp contains an amount of lignin that allows the pulp to reach a certain GE brightness after ozone delignification, yet also reduces the viscosity during ozone delignification. It has a viscosity high enough to offset 13. A method according to claim 12, wherein the substantially delignified pulp is enabled to reach a certain strength. 14. The substantially delignified pulp is treated with an effective amount of alkaline material in an aqueous alkaline solution at a predetermined temperature that is correlated to the amount of alkaline material being combined. In combination with the quality of the lignin remaining in the substantially delignified pulp? Then, the lignin seeds solubilized from the alkaline aqueous solution are solubilized. 13. The method of claim 12, further comprising extracting a portion of the aqueous alkaline solution so as to remove qualitatively all of it and produce a pulp that is substantially free of lignin. Law. 15. Substantially lignin-free pulp is converted into substantially delignified pulp. The claim further comprises bleaching to a whiteness value substantially higher than the whiteness value of the The method according to paragraph 14. 16. The viscosity of the partially delignified pulp is greater than about 13 cps. 13. The method according to claim 12, wherein the method maintains a low value. 17. said partially delignified pulp to about 30% or more of said first value; 17. The method of claim 16, wherein the viscosity is maintained at a lower viscosity reduction. 18. 13. The method of claim 12, wherein the lignocellulosic material is hardwood. 19. The first KNo. is about 10 to 14. Law. 20. 19. The method of claim 18, wherein said first viscosity value is about 21-28 cps. 21. Said second KNo. 19. The method of claim 18, wherein: is about 5-8. 22. Said third K No. 22. The method of claim 21, wherein: is less than about 5. 23. 13. The method of claim 12, wherein the lignocellulosic material is coniferous. 24. The first KNo. is about 20 to 24. Law. 25. Said second KNo. 24. The method of claim 23, wherein: is about 7-10. 26. 13. The method of claim 12, wherein the oxygen delignification treatment is carried out on pulp of intermediate consistency. 27. A partial delignification process involves subjecting the pulp to a predetermined period of time that is correlated to the amount of alkaline material. treated with a predetermined amount of alkaline substance in an alkaline aqueous solution at a predetermined temperature. substantially completes the substantially uniform distribution of the alkaline material in the pulp; increases the consistency of the pulp after completion of the processing step; and converts the pulp containing the increased consistency of the alkaline material to a high consistency of oxygen. 13. The method of claim 12, further comprising subjecting to delignification to obtain a partially delignified pulp. 28. The viscosity of the substantially delignified pulp is greater than about 10 cps. 13. The method according to claim 12, wherein the method is maintained at a low value. 29. 29. The method of claim 28, wherein said substantially delignified pulp is maintained at a viscosity reduction of about 30% or less of the viscosity of said partially delignified pulp. 30. A further delignification step increases the consistency of said partially delignified pulp; pulverizing a pulp of increased consistency to a predetermined particle size; and uniformly contacting said pulverized pulp with said effective amount of ozone as the pulp is advanced through the process. 13. The method of claim 12, further comprising: 31. The particle size of the pulp of increased consistency is Fine powder to a particle size that facilitates uniform contact with ozone with little decomposition of the ozone components. 31. The method of claim 30. 32. 32. The method of claim 31, wherein the pulp is pulverized to about 5 mm and proceeded during the process to avoid non-uniform application of ozone to the pulp. 33. 33. The method of claim 32, wherein the pulverized pulp is passed in cocurrent with ozone. 34. 33. The method of claim 32, wherein the pulverized pulp is passed in countercurrent with the ozone. 35. 16. The method of claim 15, wherein the substantially lignin-free pulp is bleached with chlorine dioxide. 36. 16. A method according to claim 15, wherein the substantially lignin-free pulp is bleached with peroxide. 37. The bleaching process reduces the GE brightness of the substantially lignin-free pulp. 37. The method of claim 35 or 36, wherein the method is increased by at least about 70%. 38. The bleaching process reduces the GE brightness of the substantially lignin-free pulp. 37. The method of claim 35 or 36, wherein the method is increased by at least about 80%. 39. The bleaching process reduces the GE brightness of the substantially lignin-free pulp. 37. The method of claim 35 or 36, wherein the method is increased by at least about 90%. 40. The lignocellulosic material may be partially delignified to a K No. of about 10 or less. and producing a pulp having a viscosity greater than about 13 cps; and said pulp is further delignified with an effective amount of ozone for a sufficient period of time to provide a KNo. of less than about 5. 1. A method for delignifying and bleaching lignocellulosic material, the method comprising: obtaining a substantially delignified pulp having a viscosity greater than about 10 and a GE brightness of at least about 50%. 41. The lignocellulosic material is softwood and has a K No. 7 to 10 before further delignification with ozone. and partially delignified into a pulp having a viscosity greater than about 13. 42. The softwood pulp has a K No. of about 3-4 after said further delignification with ozone. , a viscosity greater than about 10 and a GE whiteness of at least about 50%. The method according to item 41. 43. The lignocellulosic material is hardwood and has a K No. 5 to 8 before further delignification with ozone. and partially delignified into a pulp having a viscosity greater than about 13. 44. The hardwood pulp has a KHo. of about 3-4 after further delignification with ozone. , a viscosity greater than about 10, and a GE brightness of at least about 55%. The method according to paragraph 43. 45. Substantially delignified pulp is treated as a function of the amount of alkaline material. solubilize a significant portion of the lignin remaining in the pulp in combination with an effective amount of alkaline material in an aqueous alkaline solution at a predetermined temperature for a predetermined time, and then remove the solubilized lignin from the aqueous alkaline solution. substantially all removed, and 41. The method of claim 40, further comprising extracting a portion of the aqueous alkaline solution to produce a pulp that is substantially free of lignin. 46. Claim 45, wherein said extraction step increases the whiteness of the pulp by about 2%. How to put it on. 47. 46. The method of claim 45, further comprising bleaching the substantially lignin-free pulp with one of chlorine dioxide or peroxide to increase the GE brightness to at least about 70%. 48. 48. The method of claim 47, wherein the GE brightness is increased by at least about 80%. 49. 48. The method of claim 47, wherein the GE brightness is increased by at least about 90%. 50. 46. The method of claim 45, wherein the lignocellulosic material is partially delignified by oxygen delignification treatment. 51. 51. The method of claim 50, wherein the oxygen delignification treatment is carried out on pulp of intermediate consistency. 52. The lignocellulosic material produces a pulp with a relatively low consistency of less than 10% by weight; When the consistency of the pulp is determined in advance as a function of the amount of alkaline material treatment with a predetermined amount of alkaline material in an aqueous alkaline solution at a predetermined temperature for a period of time to substantially complete a substantially uniform distribution of the alkaline material in the pulp; At least about 20% by weight and partially delignified by subjecting the pulp containing increased consistency of alkaline material to high consistency oxygen delignification to a K No. of about 9 or less. and a partially delignified pulp having a viscosity of about 13 or more. Law. 53. Partial delignification of lignocellulosic material to produce pulp; reducing the consistency of the pulp to a low consistency of less than 10% by weight; alkaline treatment to substantially complete a substantially uniform distribution of alkaline materials in the pulp; and after completion of the treatment step, the consistency of the pulp is reduced to at least about 20% by weight. The pulp containing the increased consistency of alkaline material is subjected to high consistency oxygen delignification with a K No. of about 9 or less. and viscosity greater than about 13 cps. The partially delignified pulp is further delignified with an effective amount of ozone for a sufficient period of time to obtain a partially delignified pulp having a K No. of about 5 or less. , obtain a substantially delignified pulp having a viscosity greater than about 10 and a GE brightness of at least about 50%; Solubilizing a significant portion of the lignin remaining in the pulp in combination with an effective amount of alkaline material in an aqueous alkaline solution at a predetermined temperature over a determined period of time; substantially all of the lignin solubilized from the aqueous alkaline solution. removing and extracting a portion of the aqueous alkaline solution to produce a substantially lignin-free pulp; and bleaching the substantially lignin-free pulp to reduce its GE brightness to at least about 70%. By delignifying lignocellulosic materials, which are characterized by How to whiten. 54. 54. The method of claim 53, wherein the GE brightness is increased by at least about 80%. 55. 54. The method of claim 53, wherein the GE brightness is increased by at least about 90%. 56. The lignocellulosic material is softwood and has a K No. 8 to 9 before further delignification with ozone. and partially delignified into a pulp having a viscosity greater than about 14. 57. The softwood pulp has a K No. of about 3-4 after said further delignification with ozone. , a viscosity greater than about 10 and a GE whiteness of at least about 54%. The method according to item 56. 58. If the lignocellulosic material is hardwood, the above-mentioned further deriging by ozone Approximately 6 to 7 KNo. and partially delignified to a viscosity higher than about 15 54. The method of claim 53, wherein the method is 59. The hardwood pulp has a K No. of about 3-4 after said further delignification with ozone. , a viscosity greater than about 10 and a GE whiteness of at least about 63%. Scope of Claim 58. 60. Partially delignified lignocellulosic material is converted into lignocellulosic material. 54. A process according to claim 53, obtained by high quality kraft pulping, kraft-AQ pulping or extended delignification. 61. Increased consistency pulp KNo. is reduced by at least about 60% during the oxygen delignification process with little damage to the cellulose content of the pulp. 54. The method of claim 53, comprising: 62. 54. The method of claim 53, wherein the pulp is subjected to high consistency oxygen delignification without substantially changing the viscosity of the pulp. 63. KNo. of pulp during oxygen delignification process. 54. The method of claim 53, comprising reducing the viscosity to viscosity ratio by at least 25%. 64. Pulp consistency treated with aqueous alkaline solution before oxygen delignification 54. The method of claim 53, wherein the concentration ranges from about 1 to 4.5% by weight. 65. The consistency of the pulp is reduced to approximately 25-35% before the oxygen delignification process. 54. The method according to claim 53, wherein the amount is increased to %. 66. 54. The method of claim 53, wherein the amount of alkaline material distributed into the low consistency pulp before the oxygen delignification step ranges from about 15 to 30% by weight based on the dry weight of the pulp. . 67. The alkaline aqueous solution has a concentration of alkaline substances of about 20 to 120 g/l; 67. The method of claim 66, wherein the temperature of the alkaline material in the low consistency pulp ranges from about 6.5 to 13 g/l. 68. 54. The method of claim 53, wherein the alkaline treatment step is conducted at a temperature of about 32-66C (90-150F) for a period of about 1-15 minutes. 69. The first pulp produced is brown stock pulp, and the pulp 54. The method of claim 53, wherein at least a portion of the liquid obtained from the alkaline solution during the consistency increasing step is recycled to the alkaline treatment step. 70. Kraft pulping of lignocellulosic materials, Kraft-AQ pulping, and K No. 10-24 due to prolonged delignification. brown strike with reducing the consistency of said pulp to about 1-4.5% by weight; and heating the pulp of reduced consistency to about 32-66°C (90-150°C) for a period of about 1-15 minutes. F) with a concentration of alkaline substances of about 20-120 g/l at a temperature of A predetermined amount of alkaline substances in an alkaline aqueous solution to Processing to substantially complete a qualitatively uniform distribution (so that the concentration of alkaline substances in the pulp of reduced consistency during this processing step ranges from about 6.5 to 13 g/l). increasing the consistency of the alkali-treated pulp to about 25-35% by weight; subjecting the increased consistency pulp to high consistency enzymatic delignification without substantially changing the viscosity of the pulp; KNo. of about 10 or less. and producing a partially delignified pulp having a viscosity greater than about 13% (wherein the KNo. to viscosity ratio of said pulp is reduced by at least about 25% during oxygen delignification); The oxygen delignified pulp is further delignified with an effective amount of ozone for a sufficient period of time to provide a KHo of less than about 5. , a viscosity greater than about 10 and at least obtained a substantially delignified pulp with a GE brightness of about 50%; Effective amount of alkali in aqueous alkaline solution at temperature in combination with a lignin substance to solubilize a significant portion of the lignin remaining in the pulp; to remove substantially all of the solubilized lignin from the aqueous alkaline solution and to produce a pulp that is substantially free of lignin. extracting a portion of the aqueous alkaline solution; and bleaching the substantially lignin-free pulp to increase its GE brightness by at least about 70%. How to whiten. 71. 71. The method of claim 70, wherein the GE brightness is increased by at least about 80%. 72. 71. The method of claim 70, wherein the GE brightness is increased by at least about 90%. 73. Increased consistency pulp KNo. During the oxygen delignification process, the cellulose content of the pulp is reduced by at least about 60% with little damage. 71. The method of claim 70, comprising: 74. Bleaching the substantially lignin-free pulp with chlorine dioxide or peroxide 71. The method of claim 70. 75. 75. The method of claim 74, wherein the peroxide is hydrogen peroxide. 76. A chelating agent is added to the pulp before ozone delignification to remove metal ions. 71. The method of claim 70, further comprising rendering the ozone substantially non-reactive. 77. 77. The method of claim 76, wherein the chelating agent is DTPA, EDTA or oxalic acid. 78. Adding a sufficient amount of acidic substances to the pulp before ozone delignification 71. The method of claim 70, further comprising adjusting the pH of the pulp to a range of about 1-4. 79. 71. The method of claim 70, further comprising increasing the consistency of the pulp to about 25-50% by weight prior to ozone delignification. 80. 80. The method of claim 79, wherein the consistency of the pulp is increased to about 35-40% by weight prior to ozone delignification. 81. 71. The method of claim 70, comprising comminuting the pulp to a diameter of less than about 51 mm after oxygen delignification and before ozone delignification. 82. Maintaining the pulp at a temperature below about 49°C (120°F) during ozone delignification 71. The method of claim 70, further comprising holding. 83. 71. The method of claim 70, wherein ozone is provided by a mixture of ozone and oxygen. 84. Claim 83, wherein the concentration of ozone in the mixture is about 1-8% by volume. How to put it on. 85. 71. The method of claim 70, wherein ozone is provided by a mixture of ozone and air. 86. 86. The method of claim 85, wherein the ozone concentration is about 1-4% by volume. 87. 71. The method of claim 70, comprising proceeding the partially delignified pulp through an ozone delignification step in such a way that substantially all of the pulp is exposed to ozone. 88. 88. The method of claim 87, comprising introducing ozone countercurrently to the advancing pulp. 89. 88. The method of claim 87, comprising introducing ozone cocurrently with the advancing pulp. 90. Pulping partially delignifies the lignocellulosic material to produce a pulp, and the pulp is delignified with oxygen to a K No. of about 10 or less. and producing a partially delignified pulp having a viscosity greater than about 13 cps; adding a chelating agent to said pulp to render metal ions therein non-reactive to ozone; and adjusting the pH of said pulp. by adding a sufficient amount of an acidic substance thereto to a pH in the range of about 1 to 4; increasing the consistency of said pulp to about 25 to 50%; said increased consistency. of pulp to a diameter of less than about 5 mm; The pulp of increased consistency is exposed to an effective amount of ozone for a sufficient period of time by advancing the pulp in such a manner as to expose substantially all of the pulp to ozone. Further delignification is carried out in the zone to obtain a KNo. of about 5 or less. , a viscosity greater than about 10 and less than Obtaining a substantially delignified pulp having a GE brightness of at least about 50%; an effective amount of aliquots in an aqueous alkaline solution at a predetermined temperature for a predetermined period of time. in combination with an alkaline material to solubilize a significant portion of the remaining lignin in the pulp; to remove substantially all of the solubilized lignin from the alkaline aqueous solution and to produce a pulp that is substantially free of lignin. and bleaching the substantially lignin-free pulp with chlorine dioxide to increase its GE whiteness to at least about 70%. How to bleach and bleach. 91. 91. The method of claim 90, wherein the GE brightness is increased by at least about 80%. 92. 91. The method of claim 90, wherein the GE brightness is increased by at least about 90%. 93. The pulping process includes kraft pulping, and the oxygen delignification process includes pulping. The K No. of the pulp can be adjusted without damaging the cellulose component of the pulp or changing the viscosity of the pulp. 91. The method of claim 90, wherein: 94. 94. The method of claim 93, wherein the pulping step comprises Kraft AQ pulping. 95. The oxygen delignification process improves the K No. of the pulp without significantly damaging the cellulose component of the pulp or changing the viscosity of the pulp. 95. The method of claim 94, wherein the method reduces by at least about 60%. 96. The pulping process is a combination of Kraft AQ pulping and extended delignification. The oxygen delignification process improves the KNo. at least 91. The method of claim 90, wherein the method reduces the amount of water by about 60%. 97. During ozone delignification, the pulp is 91. A method as claimed in claim 90, proceeding in such a way that the temperature is maintained at full temperature. 98. 91. The method of claim 90, wherein a chelating agent and an acid are added to the pulp in a mixing chamber. 99. 99. The method of claim 98, wherein at least a portion of the liquid separated from the pulp during the consistency increasing step is recycled to the mixing chamber. 100. 99. The method of claim 98, wherein the pulp is advanced in co-current with ozone. 101. 99. The method of claim 98, wherein the pulp is advanced in countercurrent with the ozone. 102. Pulping partially delignifies the lignocellulosic material to produce pulp. The pulp is delignified with oxygen to a K No. of about 10 or less. and producing a partially delignified pulp having a viscosity greater than about 13 CPS; adding a chelating agent to said pulp to non-react with the metal ions therein to ozone. adjusting the pH of said pulp to a pH range of about 1 to 4 by adding thereto a sufficient amount of an acidic substance; raising the consistency of said pulp to about 25 to 50%; pulverizing the increased consistency pulp to a diameter of less than about 5 mm; further deriging the increased consistency pulp with an effective amount of ozone for a sufficient period of time; K No. of about 5 or less. , obtain a substantially delignified pulp having a viscosity greater than about 10 and a GE brightness of at least about 50%; The nitrated pulp is combined with an effective amount of alkaline material in an aqueous alkaline solution at a predetermined temperature for a predetermined period of time that is a function of the amount of alkaline material. together with solubilizing a significant portion of the lignin remaining in the pulp; extracting a portion of the aqueous solution; and bleaching the substantially lignin-free pulp with peroxide to reduce its GB brightness. Delignification of lignocellulosic material characterized by increasing the lignocellulosic content by at least about 70%. How to oxidize and bleach. 103. Claim 102: Increases GE whiteness by at least about 80%. How to put it on. 104. Claim 102: Increases GE whiteness by at least about 90%. How to put it on. 105. the pulping step comprises kraft pulping, and the oxygen delignification step does little to damage the cellulose content of the pulp or change the viscosity of the pulp; Enade Pulp K No. 103. The method of claim 102, wherein the method reduces by at least about 60%. 106. According to claim 102, the pulping step includes Kraft AQ pulping. How to put it on. 107. The oxygen delignification process improves the K No. of the pulp with little damage to the cellulose component of the pulp or little change in the viscosity of the pulp. 107. The method of claim 106, wherein the method reduces by at least about 60%. 108. The pulping process is a combination of Kraft AQ pulping and extended delignification. The oxygen delignification process loses most of the cellulose content of the pulp. The KNo. of the pulp can be improved without damaging it or changing the viscosity of the pulp. less 103. The method of claim 102, wherein the method reduces both by about 60%. 109. Ozone delignification is the KNo. 103. A method according to claim 90 or claim 102, wherein the method reduces by at least 50%. 110. 103. The method of claim 90 or claim 102, wherein the bleaching step increases the GE brightness of the pulp by at least 50%. 111. 111. The method of claim 110, wherein the GE brightness of the pulp is increased to at least 83%. 112. Pulping partially delignifies the lignocellulosic material to produce pulp. washing the pulp, and delignifying the pulp with oxygen to a K No. of about 10 or less. and partially delignified with a viscosity greater than about 13 cps. producing a partially delignified pulp; washing the partially delignified pulp; and further delignifying the partially delignified pulp with an effective amount of ozone for a sufficient period of time to produce about 50% ozone. Below Below KNo. , a viscosity greater than about 10 and a GE whiteness of at least about 50%. obtain a substantially delignified pulp; obtain a substantially delignified pulp; wash the pulp; the substantially delignified pulp is solubilizing a substantial portion of the lignin remaining in the pulp in combination with an effective amount of an alkaline substance in an aqueous alkaline solution at a predetermined temperature for a predetermined period of time; extracting a portion of the alkaline aqueous solution to remove all of the pulp and produce a pulp that is substantially free of lignin; washing the pulp that is substantially free of lignin; bleaching the lignocellulosic material by bleaching the pulp with chlorine dioxide or one of the peroxides to increase its GE whiteness to at least about 0%; and washing the bleached pulp. how to. 113. Claim 112: Increases GE whiteness by at least about 80%. How to put it on. 114. Claim 112: Increases GE whiteness by at least about 90%. How to put it on. 115. The bleaching pulp washing process washes the pulp with fresh water and the resulting washing water stream 113. The method of claim 112, comprising separating pulp from the output. 116. The bleaching process uses chlorine dioxide and bleach pulp wash water effluent is discharged. 113. The method of claim 112. 117. The bleaching process uses chlorine dioxide and the bleach pulp wash water effluent is treated by reverse osmosis to produce a treated filtrate, and then a small portion of said treated filtrate is Claims that the pulp, at least a portion of which is substantially free of lignin, is sent to a washing process. 112. The method according to paragraph 112. 118. the bleaching process uses peroxide and at least a portion of the bleached pulp is 113. A method according to claim 112, wherein the pulp is recycled to the step of washing the pulp, which is qualitatively free of lignin. 119. The washing process for substantially lignin-free pulp includes washing said pulp with bleached pulp wash water, separating the pulp from the resulting wash water, and removing a small amount of said wash water. 119. The method of claim 117 or claim 118, comprising sending at least a portion of the substantially delignified pulp to a washing step. 120. The substantially delignified pulp washing step comprises washing said pulp with substantially lignin-free pulp washing water, separating the pulp from the resulting washing water, and discharging at least one portion of said washing water. 120. The method of claim 119, comprising sending a portion of the substantially delignified pulp to a washing step. 121. The partially delignified pulp washing step comprises washing said pulp with substantially delignified pulp wash water, separating the pulp from the resulting wash water, and removing at least one of said wash water. This includes sending a portion to the pulp washing process. Scope of Claim 120. 122. A pulp washing process converts the pulp into a partially delignified pulp. 122. The method of claim 121, comprising washing with a pulp wash water, separating the pulp from the resulting wash water, and recovering and concentrating the wash water before incineration in a recovery boiler. 123. 123. The method of claim 112 or 122, wherein the bleaching step uses chlorine dioxide having a minimal chlorine content. 124. If the water demand of the cleaning process is normal CEDED process or OC/DED 123. The method of claim 112 or claim 122, wherein the process is significantly reduced compared to the process. 125. Claim 116, wherein the discharge effluent has a color content of less than or equal to about 2 pounds/ton, a BOD5 value of less than or equal to about 2 pounds/ton, and a total organic chloride content of less than or equal to about 2. How to put it on.