KR100320019B1 - Method of preparing pelletized activated carbon from wood - Google Patents

Abstract

The present invention relates to a method for producing wood-activated activated carbon, and according to the method of the present invention, after the carbide of the pulverized wood raw material is formed by mixing a predetermined amount with bentonite and molasses, the molding is aged, dried and steam activated. In addition to producing high quality granular activated carbon, waste wood can be used as a raw material, thereby solving the problem of expensive activated carbon raw materials.

Description

Method of manufacturing wood-assembled activated carbon {METHOD OF PREPARING PELLETIZED ACTIVATED CARBON FROM WOOD}

The present invention relates to a method for producing wood-activated activated carbon. Specifically, the carbides of crushed wood are mixed with bentonite and molasses, and then molded, dried, and activated to form high-quality granulated activated carbon. The present invention relates to a method for recycling wood.

Activated carbon is a carbon material with advanced pore structure, and is used in various applications such as catalyst, air purification, solvent recovery, desulfurization, denitrification, water and sewage and wastewater treatment by its surface activity and adsorption function. It is constantly being developed for use in a number of advanced applications, including medical use, such as hemodialysis.

In general, the manufacturing process of activated carbon can be largely divided into sizing of raw materials by crushing and screening, pyrolitic carbonization, and activation. When the activation by steam (steam) is followed, the carbonization process is performed at about 600 ℃, when the activated carbon for water treatment treatment can be activated carbonized charcoal at 850 to 1,000 ℃. Activated carbon is divided into powder activated carbon and granular activated carbon according to the particle size, and granular activated carbon is divided into crushed activated carbon and granulated activated carbon. Compared to the crushed activated carbon, the granulated activated carbon has a certain form and is made from powdered activated carbon, so the size is more uniform and the hardness is higher.

Such activated carbon can be prepared from various plant-based or mineral-based raw materials. As representative raw materials, wood flour, sawdust, bovine seaweed (sawdust carbide), charcoal, walnut shell, palm shell, fruit seed coal and fruit keratin coal have been used. As this increased, timber with sufficient supply of raw materials became increasingly popular.

Therefore, the United States, Russia, and the Netherlands are already producing wood-activated crushed activated carbon as well as promoting research to produce high quality activated carbon. The powdered activated carbon which uses as a raw material is industrially produced. However, it was still difficult to produce granulated activated carbon having a relatively complicated manufacturing process such as using wood as a raw material and using a binder. In the case of our country, we have not yet produced activated carbon made from wood, so we are importing wood powder activated carbon from China and wood granular activated carbon from the United States, Russia and the Netherlands at a high price.

Accordingly, the present inventors have conducted intensive studies to produce granulated activated carbon using wood as a result, and after mixing the carbide of the crushed wood raw material with bentonite and molasses as a binder, and molding the molded product, drying and activating, The present invention has been found to be capable of producing high-quality wood granular activated carbon having excellent hardness.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing high-quality wood granular activated carbon having excellent hardness, and in particular, to provide a method for recycling resources and achieving price competitiveness by using waste wood as a raw material of activated carbon.

1A and 1B are graphs showing the surface area and the pore volume of the granular activated carbon prepared in Example 1 according to the present invention,

Figure 2a to 2c is a graph showing the hardness, iodine adsorption capacity and packing density of the granulated activated carbon activated for 1 hour at 850 ℃ while varying the molasses and bentonite content,

3A to 3C, 4A to 4C, and 5A to 5C are graphs showing hardness, iodine adsorption capacity, and packing density of granulated activated carbon prepared by changing molasses and bentonite contents, and activation temperature.

In order to achieve the above object, in the present invention, the ground material is mixed with bentonite and molasses so as to include 1.5 to 10% by weight of bentonite and 25 to 35% by weight of molasses after crushing the carbide of the wood raw material, and molding the resulting mixture It provides a method for producing wood-activated activated carbon, including aging and drying and then activated by steam.

Hereinafter, the present invention will be described in more detail.

As the wood raw material of the granulated activated carbon according to the present invention, waste wood felling, waste building materials, waste wrapping wood and the like can be used.

According to the present invention, the carbide obtained by carbonizing the wood raw material is, for example, pulverized to 140 to 180 mesh and dried, and includes 1.5 to 10% by weight of bentonite and 25 to 35% by weight of molasses. The resulting carbonized wood mill is mixed uniformly with the binder bentonite and molasses.

At this time, the bentonite and molasses used as the caking agent are mixed with the wood mill in a state dissolved in water of 55 to 65 ℃, and finally produced when mixed with the wood mill within the above amount range on a solid basis It can improve the hardness of activated carbon products and at the same time satisfy other characteristics required for activated carbon such as packing density and iodine adsorption capacity.

According to the invention, the resulting mixture of wood raw material and caking additive can be molded into a circumferential shape of, for example, a diameter of 3 to 5 mm and a length of 5 to 10 mm via a granulator, the molding being aged at room temperature for about 24 hours. Then dried at a temperature of 100-140 ° C. for about 24 hours. Molded and dried as described above may be further carbonized at a temperature of 300 to 600 ℃ prior to the subsequent activation process.

Subsequently, the activation treatment of the molding of the present invention is performed for 1 to 3 hours by steam in a rotary kiln under a temperature condition of 850 to 950 ° C. In this case, by filling the inside of the rotary kiln with nitrogen gas in advance, it is possible to prevent the molded carbide from reacting with the air and oxidize. After the carbide is added, the nitrogen gas may be shut off and water vapor may be immediately introduced.

Water vapor activation of the molded carbide proceeds in two stages. Specifically, in the first heating stage, fine pores in which the unstructured portion of the carbide is selectively decomposed and consumed and closed in the carbon structure (between carbon crystals) are formed. The internal surface area is rapidly increased to open, and in the second gasification reaction, carbon crystals constituting carbide or carbon constituting minute pores are reacted and consumed to form large voids in a complex structure. That is, the formation of pores is closely related to carbon consumption in the second gasification reaction step. When the reaction consumption rate is 50% or less, the activated carbon having the major micropores is obtained, and when the reaction consumption rate exceeds 75%, the macropores in the activated carbon increase. do.

According to the method of manufacturing granulated activated carbon of the present invention, not only can produce a high-quality wood granular activated carbon having a hardness of 95% or more (yield: 30 to 50%), but also discarded waste wood, waste building materials and waste packaging wood It can be used as a raw material for wood, which can solve the problem of expensive activated carbon raw materials, which depend on imports.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto, and the evaluation of various characteristics of the activated carbon produced in the examples of the present invention was performed by the following method.

(1) particle size

100 g of granular activated carbon sample using sieves stacked on the base plate step by step (using 6 sieves) from the sieve of one step smaller than the lower limit of the particle size range to the sieve of one step larger than the upper limit. After sifting, the weight of the sample remaining on each sieve and the saucer was measured, and the particle size was calculated according to the following equation (1).

Particle Size (%) = W _i / S × 100

Where

W _i is the weight (g) of the sample remaining on each sieve or saucer, and S is the sum (g) of sample weight remaining on each sieve or saucer.

(2) hardness

Using two sieves at the intervals corresponding to the upper and lower limits of the sample particle size, sift the particulate activated carbon sample for 10 minutes, and lightly tap the sifted sample to the measuring cylinder 100 ml scale and measure the weight (W). Afterwards, each of the steel balls polished to 12.7 mm and 9.5 mm in diameter was placed in a hardness test dish and shaken with a sieve shaker for 30 minutes. Then, the sieve below two stages of the sieve scale interval corresponding to the lower limit of the particle size range After putting all the samples except steel balls on the sieve shaker using the saucer, shake them for 3 minutes, and measure the weight (S) of the sample remaining on the sieve and saucer, The hardness was calculated.

Hardness (%) = W / S × 100

In the above formula, W is the weight (g) of the sieved sample filled in the measuring cylinder, S is the sum (g) of the sample weight remaining on the sieve and the saucer.

(3) filling density

After filling the granular activated carbon sample in a packing density measuring container so that the top surface of the sample has a constant height, the sample was taken out, dried in a constant temperature dryer at 115 ° C. for 3 hours, and then weighed to calculate the packing density according to Equation 3 below. It was.

Fill Density (g / ml) = S / V

Where S is the weight (g) of the sample and V is the volume (ml) of the filling density measuring vessel.

(4) Iodine adsorption performance

After iodine solution was added to the activated carbon sample for adsorption, the supernatant was separated, starch solution was added as an indicator, and titrated with sodium thiosulfate solution to determine the amount of iodine adsorption from the residual iodine concentration. The adsorption amount when the residual concentration of iodine was 2.5 g / 1,000 ml was determined to obtain the iodine adsorption performance (mg / g).

(5) pore distribution and specific surface area

The pore distribution and specific surface area of the activated carbon samples were measured using a BET device (model: ASAP 2000, USA).

Example 1

Oak charcoal was pulverized to 170 mesh and dried, and the oak charcoal pulverized mixture was uniformly mixed with bentonite and molasses to contain 1.5% by weight of bentonite and 25% by weight of molasses. Subsequently, the resultant mixture was passed through a granulator to form a cylindrical granule having a diameter of 4 mm and a length of 5 to 10 mm, and then aged at room temperature for 24 hours and dried at 120 ° C. for 24 hours, and then the molding was sufficiently carbonized at 400 ° C. I was. After putting the mixture into the rotary kiln filled with nitrogen gas, using a steam generator equipped with a circular double copper pipe having a hot wire around it, the internal temperature of the steam generator was 350 ° C while distilled water was flowed through the pipe. The steam activation treatment of the sample mixture was carried out at 900 ° C. for 1 hour by flowing the generated steam (internal temperature: 115 ± 5 ° C.) when flowing into the rotary kiln. In order to confirm the quality of the prepared granular activated carbon, an analysis was conducted according to KS standards, and the results are shown in Table 1 below.

1A and 1B are graphs showing the surface area and the pore volume of the granulated activated carbon, respectively, and the surface area of the activated carbon was found to be 950 m ² / g. It can be seen that.

Comparative example

Granulated activated carbon was prepared in the same manner as in Example 1, except that bentonite was not used. In order to confirm the quality of the prepared granular activated carbon, an analysis was conducted according to KS standards, and the results are shown in Table 1 below.

Item KS standard (granular activated carbon) Example Comparative example 1st grade 2nd class Level 3 Dry weight loss (%) 5.0 or less 5.0 or less 5.0 or less 4.5 4.3 Hardness(%) over 90 over 90 over 90 96 50 Filling density (g / ml) 0.48 or less 0.52 or less 0.56 or less 0.32 0.37 Iodine Adsorption (mg / g) 1100 or more More than 1000 More than 900 1100 960 Particle size (%) 95 or more over 90 over 90 96 93

From the above Table 1, the activated carbon prepared in the Example is a high quality activated carbon satisfying all the standards of the KS standard, whereas the activated carbon of the comparative example using only molasses as a caking agent has a particularly low hardness of 50%, which is valuable as a product. It can be seen that there is no.

Example 2

Based on the method for preparing activated carbon of Example 1, mixing, forming, ripening, drying and carbonizing while changing the bentonite content to 1.5, 2.5, 5, 10 and 20% by weight for the molasses content of 25, 30 and 35% by weight, respectively. The prepared sample mixture was activated at 850 ° C. for 1 hour to produce granulated activated carbon. Hardness, iodine adsorption power and packing density of the prepared granular activated carbon were measured and shown in FIGS. 2A to 2C, respectively.

2a and 2c, activated carbon containing 1.5 to 10% by weight of bentonite meets the specifications of granular activated carbon while hardness, iodine adsorption capacity and packing density all at 25 to 35% by weight molasses and activation temperature of 850 ° C. In the case of activated carbon containing 20% by weight of bentonite, iodine adsorption power and packing density are drastically lowered, which is not preferable.

Example 3

Based on the method for preparing activated carbon of Example 1, the mixed, molded, aged, dried and carbonized samples while changing the bentonite content to 1.5, 2.5, 5 and 10% by weight for the molasses content of 25, 30 and 35% by weight, respectively The mixture was activated for 1 hour at 850, 900 and 950 ° C. to produce granulated activated carbon. The hardness, iodine adsorption capacity and packing density of the prepared granular activated carbon were measured, and the hardness of granulated activated carbon containing molasses at 25, 30, and 35% by weight was shown in FIGS. 3A to 3C, and iodine adsorption power was shown in FIGS. 4A to 4C. Are shown in Figures 5a to 5c.

3A to 3C, 4A to 4C, and 5A to 5C, the bentonite content was limited to 1.5 to 10% by weight, and the activation treatment temperature was changed to 850, 900, and 950 ° C instead, to activate 850 to 950 ° C. It can be seen that activated carbon having hardness, iodine adsorption capacity, and packing density at all treatment temperatures was produced.

According to the method of manufacturing granulated activated carbon of the present invention, not only can produce high-quality wood granular activated carbon having a hardness of 95% or more, but also waste wood, waste building materials, and waste wood can be used as raw materials for import. It can solve the problem of expensive activated carbon materials that depend on.

Claims (6)

After the carbide of the wood raw material is pulverized, the pulverized product is mixed with bentonite and molasses so as to contain 1.5 to 10% by weight of bentonite and 25 to 35% by weight of molasses, the resulting mixture is molded, aged and dried, and then activated by water vapor. Comprising, wood granular activated carbon. The method of claim 1, Prior to the activation treatment, further characterized in that the mixture is further carbonized at a temperature of 300 to 600 ° C. The method of claim 1, A method characterized in that the wood raw material is waste timber, waste building material or waste packaging. The method of claim 1, Pulverizing the carbide of the wood raw material to 140 to 180 mesh. The method of claim 1, The molding is aged at room temperature for about 24 hours and then dried at 100 to 140 ° C. for about 24 hours. The method of claim 1, The steam activation process is carried out for 1 to 3 hours under the temperature conditions of 850 to 950 ℃.