IL30416A - Production of carbon black and resultant products - Google Patents

Description

PRODUCTION Or CARBON SLACK ANO flfiW WT mww9 PRODUCTION OF CARBON BLACK AND RESULTANT PRODUCTS Abstract This invention relates to carbon black. More particularly, it relates to a new and useful mode of controlling the properties of carbon black while it is being produced in accordance with the furnace process.

Background The furnace process is character zed by a number of features which clearly set it apart from other methods. One such feature is the fact that the process is conducted in a confined zone or zones of limited cross-section ranging from a few inches to a few feet across. Hot combustion gases from the burning of fuel and/or hydrocarbon feedstock are generated on a continuous basis in the confined zone(s) or in external burners in communication with the zone(s). Sufficiently high rates of combustion are maintained to sustain a very hot (e.g. above 2000°P) flow of turbulent combustion gases moving through said zone(s) at very high, e.g. near sonic, velocities. The process is conducted in highly specialized furnaces, known as reactors, of which a wide variety are known to persons skilled in the art-.

Quite apart from being mere soot, the carbon black produced in such reactors is characterized by certain properties which, according to the manner of production, may be present in varying degrees: particle size, surface area, acidity or alkalinity (pH) , tint, ash content, modulus, structure and others.

Certain combinations of such properties are essential if the product is to be suitable for a given use, e.g. reinforcement of vulcanized rubber, whereas different combinations of such properties are required for other uses, such as utilization as a colorant for ink. Also, specifications for carbon black for a given use change from time to time as changes are made in the materials with which the carbon black must be used. For example, the introduction of a new type of synthetic rubber has at times required an adjustment of one or more properties 'of the carbon blacks offered to the rubber industry.

A thorough review of the various manufacturing conditions which affect carbon black properties will show many of them to be interlocking; that is, certain conditions affect more than one property. Such interlocking becomes a problem when the carbon black producer wishes to adjust one property of his product while minimizing changes in other properties, as is frequently the case. An example of a manufacturing condition which has heretofore had interlocking effects is the presence of calcium and other alkaline earth metals in the reaction zone of a carbon black furnace or reactor. Two distinctly different properties of carbon black which are affected by such practice are surface area and structure.

High surface area carbon blacks exhibit desirable coloring and. reinforcing powers in addition to high absorptivity. Accordingly, at an early stage the art developed various methods of enhancing or controlling surface area by regulation of the rates at which feedstock, fuel and combustion-supporting gas, e.g. air, are introduced to a reactor. Because such regulation failed to produce enough enhancement of surface area or else enhanced surface area with an- undesirably large loss of yield, it was suggested that alkaline earth metals be introduced into and dispersed in the reaction zone of a carbon black' reactor at that place where the carbon black reaction commences, e.g. at that place where the feedstock starts to decompose and the carbon black commences to form. Thus, carbon black has been prepared in a furnace having a first cylindrical zone of relatively large diameter in which a continuous turbulent stream of hot combustion gases is generated by the burning of air and natural gas. Through1 the upstream end of said first zone, along its axis, are injected a feedstock and an alkaline earth metal which, for purposes of convenience, is introduced in the form of one of its compounds which is capable of being dissociated by the heat of-1 the combustion gases along with the feedstock. The alkaline earth metal has been injected in a variety of ways, e.g. by dispersing it dry or as a water solution in the feedstock, or as a separate spray which enters the zone at the upstream end of the first zone, approximately at the axis thereof. Although this technique does permit the production of a carbon black of high surface area in a controlled manner, it will ordinarily reduce the structure of the resultant product markedly.

Thus, it is apparent that alkaline earth metals are suitable for surface area development only to the extent that the consequent lowering of structure can be tolerated. For certain applications, a simultaneous increase in surface area and decrease in structure may be desirable. In other cases, such as where the black is to be used in rubber or plastic compositions which are to be extruded, or where the black will be used as a filler in polymeric materials in which high structure blacks enhance processing capabilities, or where there is a desire to increase the tint which the black exhibits in printing inks while enhancing ink viscosity or at least minimizing losses in viscosity due to structure degradation, the degradation of structure incidental to the development of greater surface area can be a distinct disadvantage. Clearly the interlocking effect of alka- line earth metals on both surface area and structure is a problem, and there is a need for solution of such problem. The principal object of the present invention is to fulfill the aforementioned need.

Quite unexpectedly, it has been discovered that with a particular class of reactor, it is possible to produce pronounced increases in surface area as well as a high level of structure or in the alternative, to enhance the surface area while holding structure constant or at a predetermined Level. The applicable class of reactors is characterized by the ability to carry out a furnace carbon black process, as above described, and by having two distinct chambers or zones separated by a restriction or choke having an opening which has substantially less cross-sectional area than either zone. One of said zones, which will be referred to as the first zone, is fitted with means for providing hot combustion gases therein, either by injecting said gases into said zone from an external burner or by burning both fuel and feedstock in the zone itself with a combustion-supporting gas such as air. The means for providing combustion gases is spaced from the position (s) at which the feedstock enters the first zone and is positioned for directing the combustion gases downstream in the first zone along a side wall thereof and then, at the downstream end of said zone, inward toward the opening through the restriction. There is a means for injecting the feedstock which cooperates with the restriction in producing a substantial dispersion of said feedstock in the hot combustion gases by the time they enter the second zone.

The means for injecting feedstock e.g. a nozzle, is positioned for directing the spray from one or more positions "at" (e.g., on or near) the axis of the first zone and downstream towards the restriction and second zone. The downstream end of the first zone communicates through the restriction with the upstream end of the second zone. Downstream of the upstream end of the second zone is a cooling means. The cooling means may be located within or outside, e.g. beyond, the downstream end of th second zone. Preferred are those reactors having cylindrical chambers. A particularly preferred, type of reactor has a first zone whose width is greater than its length and a second zone whose width is less than its length, and the length of the second zone is signif cantly longer than that of the first. The invention is not applicable, however, to reactors which lack the aforementioned restriction (or "choke" as it is sometimes called) . . i Persons skilled in the art are aware of a variety of reactors falling within the above -described applicable class. Such reactors will, to be sure, differ from one another in the means for injecting feedstock and for providing hot combustion gases and in the positioning of such means. Other variations will be noted. However, so long as the reactor falls within the above-described class, the invention is applicable thereto. As applicable es and hydro-nd then release e of flow as discovery turbulent to the second e increased carbon black dom in the discovery that as just arth metal e same time re both emedstock into th a predeter-oth structure roduce carbon s utility. should therefore to produce a d e e e feedstock; the feedstock is maintained in said zones and in the presence of said alkaline earth metal for a contact interval of at least about 10 milliseconds and not more than about 70 milliseconds, which time interval is terminated by cooling the reaction o mass to a temperature substantially below 3000 P.

In general, the preferred feedstocks comprise the var iou petroleum residua obtained ^Ln a number of petroleum operations, as for example, the bottoms derived in a thermal or catalytic cracking of cycle oils and the like. These residua are more commonly referred to as residual oils, pitches or tars and are mainly chemically characterized by · exhibiting a high degree of aromati- city, e.g., hydrocarbons containing a hydrogen to carbon ratio less than about 1.25, and also exhibiting relatively high specific gravity, preferably less than about 10° API.

When using heavy residual oils, it will be found advantageous to preheat them in a manner known to the art prior to their injection into the first zone of the reactor. Preheat temperatures in the range of 400°F to 500°F. are common. Best results are obtained when the preheated feedstock is atomized in- the reactor at the point of injection.

The feedstock spray angle may be varied in conjunction with the practice of either aspect of the invention by substituting nozzles which differ from one another in the average included angle in their spray patterns or by employing a nozzle having an angle. By selectively varying the feedstock is possible to regulate the structure of the duced in a reactor of the applicable class in the teachings of U.S. Patent 3,222,131, issued to K. E. Powell, David C. Williams and the . However, for purposes of the present invention, that the average feedstock spray angle be at in order to obtain the novel products of the I present invention. An upper limit of about 180° has been set J upon the feedstock spray angle. Generally speaking, the objects of the invention can readily be attained by operating within this upper limit. However, it should be understood that the angle can be increased still further without harm, provided that suitable precautions are taken to avoid coking of the feedstock on the reactor walls.

The hot combustion gases employed in practicing the invention generally may be generated by the combustion of vaporous hydrocarbons such as those employed as feedstocks, or may be gaseous fuels, natural gas being preferred. Oxygen, which may be in the form of air, oxygen enriched air, gaseous oxygen or other oxygen containing gas, is supplied to support combustion. Sufficient oxygen is supplied in addition to that consumed by J the fuel to burn the indicated amount of feedstock. * Burning at - - least about 20% of the feedstock has been found essential to o production of the necessary lower temperature limit of 3000 F. Usually no more than about 70% combustion is required to produce the necessary heat. The preferred operating temperature for the process appears to be about 3200°F. to about 3400°F. but the temperature in the reactor may be higher . Higher temperatures do not adversely affect the^ process, but are hard on reactor linings .

The invention generally contemplates the introduction of calcium, barium, strontium or magnesium or mixtures thereof as metal or as compounds into the reaction mass. Where compounds are employed, they may be introduced as solids in suspension, as slurries in a dispersion liquid (e.g. water or organic carrier liquid) or as water or organic solvent solutions. Organic or inorganic compounds, such as organic acid salts, mineral acid salts and hydroxides are contemplated, but the halides, and especially the chlorides, are preferred on account of their ready availability, water solubility and reasonable cost. The amount of alkaline earth metal may be varied in accordance with the extent' of surface area development desired. However, it will seldom be found desirable to use less than .03% of the metal, calculated as free metal based on the weight of the feedstock. Ordinarily no more than 4% of the metal is required, but larger amounts- may be used if warranted by product specifications and the quality of the reactor lining. The alkaline earth metal may be injected into the reactor at any position (s) that will result in good dispersion of the metal in the reaction mass and satisfy the contact time requirements of the process. In this connection, it should be noted that the injector should be placed far enough upstream of any quench sprays in the4 reactor to insure the minimum contact time is satisfied before the reaction mass is quenched.

Where the alkaline earth metal is calcium, strontium or magnesium and it is desired to avoid the structure-degrading effect thereof, the metal(s) should' be injected downstream of the restriction between the two zones of the reactor in a weight concentration of preferably .03% to about 1.5%. ' Preferably, the injection is made immediately downstream of the restriction, since the maximum contact time is thus obtained in a reactor of a given length. In longer reactors, the metal injection means may be located well downstream of the restriction. In such case, care should be exercised to see that the cooling means (e.g. water, steam or dry quench) is located a substantial distance downstream of the metal injector. By a substantial distance is meant a distance which is long enough to provide a contact time between the reaction mass and the metal which falls within the above-mentioned time interval. * Where the alkaline earth metal is barium, it may be advantageously injected into either the first or second zone. However, it is preferably injected at the upstream end of the first zone as a separate stream or spray alongside the feedstock in a weight concentration of about 0.2 to 4% on the feedstock. Maximum contact time between the barium and the reaction mass is thereby obtained.

The use of barium in admixture with one or more of the other alkaline earth metals offers the advantage of attaining fine control over both the surface area and the structure leval of the product. For instance, it is possible to inject both barium and calcium into the first zone. The spray angle of the feedstock is set to produce approximately the desired structure level and the combined rate of introduction of barium and calcium is set to produce the desired level of surface area. Then, a fine adjustment in the structure level is made by varying the proportion of barium and calcium being charged. Barium has little or no effect on structure when used within the concentration limits set forth herein. Calcium, on the other hand, if injected into the first zone, does have substantial effects on structure. Both barium and calcium have substantial effects on surface area. Th s, a substantial change in the ratio of barium to calcium will exert a substantially greater influe.nce on structure than on surface area. Thus, by substantially varying the ratio of barium to calcium it is possible to make fine adjustments in structure level with only very small changes in surface area. If such changes in surface area are more than production goals will tolerate, such changes may be corrected by a further change, in the combined rates of barium and calcium addition. It will, of course be possible to change the combined rate of barium addition and calcium addition while simultaneously altering the ratio of such additions, and such practice is also contemplated by the invention. Generally speaking, the technique just described is useful throughout a range in which the charging ratio of barium to total alkaline earth metal (including barium) varies from about .05 to about .95 in terms of weight.

If the contact time between the alkaline earth metal and the reaction mass falls significantly below about 10 milli¬ seconds, the objects of the invention are not attained. Co tact times of more than 70 milliseconds are not proscribed. However, at the high combustion and flow rates required to maintain tern-. o peratures above 3000 F, contact times much in excess of 70 milliseconds can only be attained by substantially increasing the internal dimensions and therefore the costs of one's reactors.

From the above discussion it will be apparent that the lower limits of temperature, percentage combustion of feedstock, feedstock spray angle, concentration of alkaline earth metal, and contact time set forth in this specification and in the appended claims, are critical. If any of these conditions falls significantly below the particular minimum value which has been set forth herein, the objects of the invention are not attained. Persons skilled in the art will readily recognize, however, that the upper limits on these variables are limits of convenience and economy rather, than of operability in the absolute sense. It should also, be apparent that an increase in any of such variables increases the product property governed thereby, For instance, feedstock spray angle is substantially the governing process variable for the structure of the product. An increase in spray angle under a given set of other conditions increases structure. Temperature, alkaline earth metal concentration and contact time largely govern the surface area of the product. Thus, an increase in any of them increases the surface area of the product, provided the other two variables remain constant. In like fashion a decrease in a variable governing a particular property will decrease the extent of development of that property in the product. Therefore, the process is not operated with all three of the governing variables for' surface area at their minimum value. If any two of them are in about the lower 1/5 of their specified ranges, the remaining variable should be maintained in about the upper 1/3 of its specified range. For instance, if contact time and alkaline earth metal are in the lower 1/5 of their specified range, e.g. 20 milliseconds and 1% respectively, then the temperature should be in about the uiope 1/3 of its range, e.g. about 3300 F. or higher. Applying the above principles, persons skilled in the art will readily manipulate the various variables to obtain the novel products of the present invention.

The products of the present invention are characterized by a unique combination of properties which have never before been obtained in furna.ee carbon black as it is produced in a furnace type carbon black reactor. Although it was reported in the art that various after-treatments of impingement or chan-nel black (surface area about 110 m 2/gram) were able to raise its surface area to about 1000 m 2/gram, resulting in an objec- 2 tionable thixotropy, surface areas of about 450 m /gram have been considered extraordinarily high for carbon black' recovered from the furnace process. In contrast, the blacks produced in accord¬ ance with this invention have a surface area in the range of from 9 2 about 600 m~/gram to about.1300 m /gram. While oil factors, of about 185 ml oil per 100 grams of carbon black have been considered unusually high in the past, the carbon blacks of the present invention exhibit oil factors in the range of about 250' ml to about 450 ml per 100 grams of carbon black. Prior art channel blacks as originally produced, are normally characte ized by relatively high contents of volatile matter, e.g. 4-15%, while the high structure, high surface area furnace carbon' blacks of the present invention, as initially produced, normally exhibit a volatile content well below about 2-1/2%, e.g. 1-1/2%.- While prior art channel blacks display a definitely acid pH, e.g. about 2 - 3 , the blacks of the present invention exhibit a pH in the range of about 6 to about 10, and are thus substantially neutral to alkaline. The carbon blacks of the present invention exhibit an ash content in the range of at least about .5% to about 10%, while impingement or channel blacks normally had only a trace, e.g. less than 0.1%, of ash. In their preferred form, the products of the invention display a pH of about 6.5 to about 9.U , an oil factor of about 300 to about 400 ml per 100 grams of carbon black and a surface area of about 700 to about 1100.

The invention may be better understood by considering I certain illustrative embodiments thereof, one of" which will now be disclosed with the aid of the accompanying drawings, in which FIGURE 1 is a sectional view of a reactor adapted to carry out the process and to produce the novel products of .the . invention; and FIGURE 2 is an enlarged portion of FIGURE 1.

FIGURE 3 is a graph of a discharge curve of organic depolarized systems containing acetylene black and the carbon black of the present invention.

The reactor in which it is particularly preferred to carry out the invention is quite similar, to that shown in U. S. Patents 3,060,003 and 3,222,131, but is slightly modified in respect to burner design and provision of means for injection of alkaline earth metal. In all other respects, the reactor is capable of operating in the same manner as the one shown in the aforementioned patents, and the disclosures of said patents are incorporated herein by reference.

In FIGURES 1 and 2 of the accompanying drawing, reference numeral 1 denotes a generally tubular reactor which is divided as shown into a first chamber or zone 2, a second chamber or zone 3 and a quench chamber or zone 4 having quench ports 5. As illustrated, the quench zone constitutes an extention of the second zone. The first zone, however, is of greater width and shorter length than the second zone. For optimum results, moreover, it is preferred that the width of the first zone be. greater than its length.

First zone 2 has an inlet opening through which injector assembly 6 projects, while quench zone 4 is provided- with an outlet opening for withdrawal of reaction products. Positioned in the inlet end of the second zone is a replaceable choke ring 7 of a high temperature refractory material having an orifice 8.

Injector assembly 6 comprises substantially tubular members 9, 10 and 11, members 9 and 10. supporting a heat resistant ring member 12 between their inner ends. Fixed to the end of member 11 within the first zone is a circular deflector 13 having a diameter substantially equivalent to that of member 9, - - so as to provide a circumferential orifice 14 of desired width between ring member 12 and heat resistant stainless steel insert 15.

Extending through tubular member 11 are a hydrocarbon feedstock conduit 16 and nozzle or injector 17. Connected to zone 1 through tubular member 11 is a source of "axial air", or other gas for discouraging coke formation around the feedstock nozzle. In like manner, a source of an oxygen-bearing combustion supporting gas, herein referred to as "process air," is connected to zone 2 through circumferential orifice 14 and conduit 10.

The means for injecting the fuel into zone 2 may take various forms, a particularly effective arrangement comprising a conduit 19 connecting the source of fuel to the interior1 of enclosed space 27 between tubular members 9 and 10. Ring 12 constitutes one end of space 27 and it is provided with a plurality of gas jets 20 which are secured at angularly spaced intervals around the front face of ring 12. The jets communicate with the enclosed space 27. The jets are directed outwardly so as to project the fuel toward the circumferential or side wall of zone 2.

Alkali metal compound injector pipes 29 and 32 are / provided. See FIGURES 1 and 2; the pipe 29 has been omitted from FIGURE 1 to simplify the drawing. Pipe 29 extends alongside the feedstock pipe 16 in tubular member 11 and has its outlet 21 adjacent feedstock spray nozzle 17. Pipe 32 is disposed in a radial port 31 through the metal casing and refractory lining of the furnace, opening into the second zone 3 immediately down-, stream of restriction or choke 7, and having its inner end slightly within the inner end of port 31. The outer ends of pipes 29 and 32, respectively, are connected to atomizers 23 and 33. The latter, in tur,n, are connected through pipes 25 and 35 with one or more sources (not shown) of alkaline earth metal solution under pressure, and through pipes 24 and 34 with a source (not shown) of high pressure air for atomizing the alkaline earth metal solution (s).

During the operation of the above-described reactor, a continuous stream of process air is injected into circumferential orifice 14 and flows radially outward passing the jets 20, at which point it is at its maximum velocity and minimum static pressure- Simultaneously, a stream of hydrocarbon fuel is injected into orifice 14 through jets 20 resulting .in a thorough and rapid mixing thereof in the process air stream.

The resultant fuel-air mixture is ignited as it passes -into zone 2, the burning mixture and its products of combustion flowing radially outward from the axis thereof as a uniformly . expanding disc-shaped stream. It then follows a flow pattern as determined by the configuration of zone 2 and as 'shown by the arrows in the drawing, flowing substantially parallel to the circumferential surface of said zone towards the opposite end thereof where it is directed radially inward toward the axis of the zone and orifice 8.

As hydrocarbon fuel and process air are introduced into the reactor, hydrocarbon feedstock is injected into zone 2 through injector nozzle 17 in the form of a vaporized or atomized spray cone. Alkaline earth metal solution is introduced to the interior of the reactor through injection pipe 29 and/or injection pipe 32 and is rapidly dispersed in the reaction mass. The temperature of the feedstock is rapidly raised as it approaches orifice 8 and it is thoroughly mixed with and dispersed in the hot combustion gases resulting from the burning of the hydrocarbon fuel. The resultant mixture of combustion products, alkaline earth metal (when pipe 29 is used) and feedstock passes through orifice 8 into zone 3, cracking of the feedstock being terminated in zone 4 by quenching with water or other suitable cooling medium introduced through quench ports 5. The cooled reaction gas with entrained carbon black then exits from zone 4 for subsequent separation and collection of. carbon black.

In order to demonstrate to those skilled in the art ; the preferred manner of carrying out the process of this invention, the following examples are given. All parts are parts by weight unless the contrary is clearly indicated. The examples are presented primarily by way of illustration, and the details described' therein are not to be interpreted as jlimitations upon the invention except to the extent require† by the appended clairhs. Considerable variation is possible. For instance, although the reactor employed in carrying out' the examples is the one shovm in the accompanying drawing and described in detail 1 · ί in this specification, those 'skilled in the art can rieadily prac- i tice the invention in other reactors within the applicable class discussed herein. Although a particular feedstock and particular conditions tending to produce; a particular grade of carbon black have been set forth for the sake of concreteness , persons skilled in the art can readily substitute other feedstocks and select different combinations of operating conditions, all in accordance with well-known principles. Other variations will readily occur to those having experience in the art of producing carbon black. * The dimensions of the reactor used, in the examples are as follows: First Zone Diameter 36 inches Length 15 inches Air Inlet Annulus Diameter 12 inches Width 3/4 inches Restriction Ring Internal Diamet 7 inches Length 9 inches Second Zone Diameter 15 inches Length 10 feet, 6 inches Additive Injector 32 Distance of pipe from downstream face of restriction 1/2 inch (approx.) Quench Sprays Distance from additive injector 32 10 feet, 5-1/2 inches (approx. ) A hydrocarbon feedstock having the following analysis is employed in the examples: Gravity, API at 60°F 2.5 Viscosity, SU sec./210°F 43.6 Conradson Carbon, percent 6.42 Correl. Index 116 Distillation : IBP°F, 760 mm 463 % 632 % 674 % > 700 % 704 40% 721 50% 739 oil began to crack Natural gas having a Btu rating of about 1050 Btu/ft net is employed as fuel with ambient air as the combustion supporting gas.

The pipe 32 for injecting the additive into the second zone of the reactor was a 1/4 inch IPS stainless steel pipe extending to within one inch of the wall of said zone. The pipe Example 1 Combustion air rate 190,000 scfh Natural gas rate 12,260 scfh Feedstock rate (metered at 60°F) 173 gph Feedstock injector spray angle 30° Feedstock preheat temperature 600°F.

The rates and other conditions set forth above, except the distance from the choke to the quenching nozzles, are such as would normally produce an ISAF grade of carbon black.

Example 2 Without changing the conditions employed in Example 1, calcium chloride solution was admitted to the reactor, solely through outlet 21 of injector pipe 29. This is the situs of injection used in prior art methods in pther reactors.

The calcium chloride was dissolved in water in a ratio of 147 pounds of calcium chloride to 300 gallons of water. The solution feed rate was 6.5 gallons per hour. Atomizing air was employed at the rate of 500 s.c.f.h. The resultant concentration of calcium chloride relative to feedstock was 0.0183 pounds per gallon (feedstock weighs about 8.8 pounds per gallon at 60°F)< or about 0.075% calcium metal based on' feedstock weight.

Example 3 Example 2 was repeated, except that the introduction of calcium chloride solution was solely through pipe 32 at the same rates and concentrations as in Example 2. he products of examples 1 through 3 were sampled and were tested for oil absorption, as a measure of and for iodine number as a measure of surface area. are set forth in the following table: Table l nt from Table I, the example in accordance ' ith the Example 3) produced a higher surface area than either (Example 1) or the prior art (Example 2) while the ion was the substantial equivalent e.g. within 5%, rol.

Example 4 n this example, the reactor was operated at a combuste of 190,000 scfh, a natural gas rate of 12,260 scfh, on ed ck r Example 9 A cathode mix for an organic depolarized cell was prepared in accordance with the following procedure: 1. Grind 100 grams meta dinitrobenzene and 4.5 grams barium chromate together with a small portion of a 50 gram sample of the above acetylene carbon black until free of lumps of m~DNB. 2. Blend the above mixture and the remaining carbon in a blender for five minutes. 3. Add 225 ml. of electrolyte which consists of a 2.5N magnesium perchlorate solution containing 0.2 grams of lithium chromate per liter. 4. The mixture is kneaded until a moist crumb is obtained. · The moist crumb was placed in a cylindrical container of plexi- glass having a magnesium anode plate at one end. A conventional coated paper separator is placed between the anode plate and the cathode mix. It serves as a conducting medium, when wetted by the electrolyte solution. At the other end of the container is a carbon rod which is embedded in the cathode mix and extends through the end wall to the positive terminal of the cell. It serves as a collector, of electric current from the anode and also is sufficiently porous to permit the escape of gas from the container which, except for the porosity of the carbon collector/ is tightly sea led .

Claims (1)

1. 2. P.A. 304l6/ll 3. WHAT IS CLAIMED ISt 1· A furnace carbon black having a surface area (iodine adsorption) of about 600 m /gram to about 13OO m2/gram, a structure level as measured by oil factor of about 250 to about ¾50 milliliters per lOO grams of carbon, a pH of about 6 to about IO, and an ash content of about 0.5$ to about 10$. 2· A furnace carbon black according to Claim 1 wherein the surface area is about 7 0 to about 1100, the oil factor is about 3Q0 to about ¾00 and the pH is about 6*5 to about 9· 5· 3· In the known process of regulating the surface area of carbon black as it is produced in the furnace process by preparing said carbon black by the decomposition of hydrocarbon feedstock in the presence of hot combustion gases and an alkaline earth metal, the Improvement which comprises in combinationt conducting said decomposition by providing said hot combustion gases in a first zone into which said feedstock is injected, turbulently mixing said feedstock and hot combustion gases and introducing them into a second zone through a restriction or choke of lesser cross-section than either of said zones, injecting an alkaline earth metal selected from the group consisting of calcium, strontium and magnesium and mixtures thereof into the resultant turbulent reaction mass in said second zone, cooling said reaction mass below reaction or dissociation temperature a substantial distance downstream of the point of injection of said alkaline earth metal and recovering the resultant 4. Process In accordance with Claim 3 wherein the alkaline earth metal is injected in the form of at least one compound of said metal or metals* 5. Process in accordance with Claim 3 in which the hot combustion gases are provided in the first zone by burning an ignitable mixture of fuel gas and air and a portion of the feedstock in said first zone. 6. A method of producing carbon black* comprising! injecting feedstock into a first confined zone as a substantially conical spray having a preselected . o average included spray angle in the range of about 60 to about 180°J providing hot combustion gases in said zone) forcing said hot combustion gases to mix with the feedstock and to enter a second confined zone by forcing them to flow through an opening of lesser cross-sectional area than either of said zones* whereby the · resultant mixture is turbulently released Into said second zone} regulating the rate of introduction of feedstock and hot combustion gases* including oxygen, into said first zone for burning about 20 to about 70 percent of the feedstock and for cracking the remainder to carbon black and by-products. at a temperature of about 30OO°P, to about 3¾00°P. in said zones; contacting said reaction mass for a contact interval of about 10 to about 70 milliseconds in a predetermined weight concentration in the range of about 0.03 to about k percent with alkaline earth metal): terminating said interval by cooling the reaction mass to a temperature substantially below 3000°F.| and recovering the resultant carbon black product. P.A. 3θ4ΐ6/ιΐ 7. Method according to Claim 6 wherein said spray is an atomized spray of liquid hydrocarbon which boils substantially above ¾00°F. * has an atomic hydrogen to carbon ratio of less than about 1*25 and has a specific gravity of less than about 10° API. 8. · Method according to Claim 6 wherein said combustion gases are provided in said first zone by igniting a mixture of fuel and air at the upstream end of said first zone as a radially outward directed disc-shaped stream which is initially out of contact with said feedstock* 9. Method according to Claim 6 wherein a mixture of alkaline earth metals is employed, wherein one of said metals is barium, and wherein the ratio of the weight rate of barium to the weight rate of total alkaline earth metal (including barium) is varied substantially for substantially varying the structure of the resultant product substantially independently of the sur ace area thereof, 10. A method of producing carbon black comprising! injecting a spray of hydrocarbon feedstock boiling above about k00°F, into a first tubular confined zone at the axis at the upsteeam end thereof as a substantially conical spray having an average included spray angle of about 60° to about 180°; causing said feedstock spray to move substantially downstream in said zone substantially out of contact with the walls thereof; providing in said zone a flow of hot combustion gases including oxygen which are introduced at the upstream end of said first P.A. 30¾16/II zone at a point spaced apart from where the feedstock enters; causing the combustion gases to flow downstream in said first zone alone the sides of the zone and then inward in said zone.at the downstream end thereof; forming an intensely hot reaction mass by forcing said hot combustion gases to mix with the feedstock and to enter a second confined zone of lesser diameter but greater length than the first by forcing the combustion gases and feedstock to flow together through a restricted opening which is of lesser cross—sectional area than either of said zones; whereby the resultant mixture is turbulently released into and is decelerated as It enters said second zone; controlling the rates of introduction of feedstock and hot combustion gases, including oxygen, into said first zone for burning at least about 20$ to about 70 of the feedstock and to crack the remainder to carbon black and by-products In said zones at a temperature in excess of about 3000°P. to about 3¾00°F, ; contacting said reaction mass for a contact inverval of about 10 to about 7 milliseconds in a weight concentration of about 0,2$> to on the weight of injected feedstock of alkaline earth metal in aqueous solution; terminating said interval by cooling the. reaction mass to a temperature substantially below about 3000°P.; and recovering the resultant carbon black product* 11. · Carbon black· whenever produced by the method claimed in Claim 10· 12. A cell containing a cathode mixture comprising a cathode compound that is reducible in said cell for the production of electric current and, in admixture with said anode compound, an amount of the product of Claim 1 which is sufficient to enhance the conductivity of the mixture and retain a substantial proportion of the electrolyte upon its surface. 13. A cell in accordance with Claim 12 wherein said cell contains as a substantial portion of said cathode mixture, an organic depolarizer. ATTORNEYS FOR APPLICANT