DE2641187A1 - Process for the production of carbon black - Google Patents

Description

Process for the production of carbon black

The invention relates to the production of high quality carbon blacks which are dry for reinforcement purposes in rubber, printing inks Clays or the like are suitable, being one of a solvent refined coal or one with a solvent extracted coal runs out. In particular, the invention provides the solvent extraction of a major amount of coal that is free from inorganic materials is presented as a material for the production of carbon black, furthermore the solvent and the extracted Coal can be used as a material for making carbon blacks. The invention therefore also relates to production of carbon blacks from these starting materials ..

The invention produces high-quality carbon blacks using solvent-extracted coal alone as the starting material

709815/1037

- r-

or used in combination with the solvent that. is used for the extraction of such coal. It The aim is to reduce the dependency on a raw material for the production of soot that can be traced back to petroleum by using solvent extracted coal alone or in conjunction with the solvent to make the supply of carbon black feedstock to increase, which is based on highly aromatic petroleum. In addition, the cost of soot should be reduced by at least partially replacing the cheaper coal for the petroleum-derived expensive carbon black feedstock components.

Soot is becoming increasingly important. For example be In the United States alone, more than 2 billion kilograms of carbon black are produced annually. There are four main types of soot, made in the United States, namely channel black, gap black, furnace black, and lamp black. Of these Carbon black is by far the most important of all, making up nearly 95% of the carbon black produced in the United States. High quality furnace blacks are made from certain petroleum refining materials generated, especially those hydrocarbons that. in the catalytic cracking of recycle oils with a high Aromatic content arise. Using these types of hydrocarbons 0.5 to about 0.65 kg of furnace carbon black is produced per liter of the recycle oil.

Channel soot is made from natural gas through unlimited partial combustion generated in the presence of a coal surface. Channel blacks are also of high quality. Approximately 31.15 cbm Gas is required to produce 1 kg of channel soot. As a result of increasing costs and the dwindling availability of Little channel black is produced in the United States, along with the low yield of natural gas.

Split soot is produced from natural gas. The yields are essential

7098 15/1037

borrowed higher and are approximately 4.5 to 6.75 kg of carbon black per 28 m ^{3 of} gas (10 to 15 pounds per 1000 cubic feet), but cracked carbon blacks are of poor quality. Split carbon blacks are not suitable for rubber reinforcement or filling purposes due to the extremely large particle size and the small surface area.

Therefore, value is currently placed on highly structured furnace carbon blacks, which are produced from liquid hydrocarbons. However, the hydrocarbon starting materials used for the production of various carbon blacks are very limited in terms of price and type. A heavy oil rich in aromatics, containing at least 50% aromatics with a high content of polynuclear components and a high level of unsaturation is used as the starting material for the production of furnace carbon blacks. In particular, a refinery catalytic cracking recycle oil is used to make most of the carbon blacks currently being made. The furnace carbon black method is carried out in a horizontal furnace high turbulence, where the atomized hot aromatic feedstock is supplied at about 500 ⁰ C. An auxiliary fuel, usually natural gas, is used to achieve the high temperature necessary to cause the incomplete carbonization and decomposition of these aromatic oil droplets in furnace black. The process usually is that the natural gas is completely combusted before the introduction of the aromatic material to produce a hot fluidizing medium with a temperature range 650-1200 ⁰ C. The greater the turbulence in the furnace soot pyrolysis zone, the finer the particle size of the soot produced. Even mixing of the atomized return oil in the hot flame gases is important to achieve the best results. The residence times at such high temperatures must be very short and on the order of thousandths of a second.

.7 09815/1037

High-quality furnace carbon blacks are suitable for reinforcing rubber, especially in the manufacture of vehicle tires.

Attempts have been made to produce coal to produce carbon black. For example, US Pat. No. 3,424,556 describes a process for the production of carbon black which consists in rapidly forming a divided coal having a particle size of less than 300 mesh to temperatures of 900 to about 1800 ^° C. in less than about 5 seconds to heat to form a tar and a gaseous material containing entrapped soot particles, whereupon the gaseous materials are cooled and the entrained soot is removed which is recovered as a product. However, the resulting carbon black, when mixed into natural rubber, only provides results that correspond to those obtained using split carbon blacks, and in some cases are even worse. It is known, particularly in the rubber mixing art, that the The best reinforcement blacks currently available to increase the abrasion resistance as well as the wear properties and strength properties of either natural rubbers or synthetic rubbers require that these rubbers be reinforced by the incorporation of approximately 40 to 60 parts of highly structured carbon blacks known as furnace blacks.

U.S. Patent 3,404,960 teaches a process for simultaneous generation of coke and soot, which consists in continuously forming a substantially flat bed of coal with a predetermined To send thickness along a horizontal bed of a predetermined length through an oven, the oven 25 to 50% the amount of air theoretically required for complete combustion of the hydrocarbons in the coal in an upward direction through the bed, reacting with some of the hydrocarbons in the coal, the temperature raise the coal in the bed to a coking temperature and

70 9 8 15/1037

partly to coke the coal and unreacted coal. ■ Hydrogen cracks with the formation of soot, being a hot one Gas flow is generated through the bed, from which the soot formed is entrained. The unreacted Hydrocarbons are cracked in both the bed and above the bed, while the partially coked coal is in directing a descending stream into a shaft furnace to stop coking the coal in that furnace. The gas stream from the carbonization furnace is withdrawn and cooled, whereby the soot is extracted. However, this method cannot produce soot that is exactly below the Standard conditions of the currently standardized qualities falls.

In contrast, according to the invention, a considerable amount of coal, specifically up to 35%, can be dissolved in a highly aromatic recycle oil which is conventionally used as such as furnace carbon black starting material. The solvation of the coal may be carried out at up to 450 to 500 ⁰ C by heating the coal / solvent suspension. The undissolved carbon and inorganic materials are then filtered out, whereupon the hot-extracted carbon / solvent solution is fed directly to a soot furnace. Another method is to recover the extracted or solvated coal in the form of a solid material, for example by evaporating the solvent and grinding the solid coal to a particle size sufficiently small for direct use in a soot furnace. Another applicable method for the utilization of coal for certain Rußzwecke is to extract the hydrocarbon portion of the coal with a suitable solvent and to marry the extracted or solvated coal from the solvent to be removed and then the solvated coal to a particle size necessary for direct use for certain carbon black purposes is sufficient.

709815/1037

_ Of _

Structurally, coals are composed primarily of high molecular weight condensed aromatic rings. NMR spectra allow an estimation of the distribution of hydrogen atoms between aromatic and non-aromatic structures. About 70% of all carbon atoms in coal are in aromatic rings, while only about 23% hydrogen atoms are linked to aromatic carbon atoms. These compounds have molecular weights in the order of magnitude of 10,000. Coal also contains oxygen, sulfur and nitrogen, these elements being mainly combined in functional groups, such as OH, CO, COOH, NH ₂ , CN, S and SH, which form an integral part of the original carbon molecule are present.

The soluble fraction of the coal, which makes up about 70 to 80% of the original organic coal materials, possesses a molecular weight of from about 250 to about 1500.

The undissolved coal contains all of the inorganic material and most of the sulfur. This material can be filtered through the hot coal extract and the solvent are separated.

The solvents used according to the invention to extract the coal are polycyclic hydrocarbons, aromatic materials, naphthenes and mixtures thereof with boiling points between approximately 240 and approximately 425 ^° C. They are liquid under the temperature and pressure conditions of the extraction.

These materials are known in refinery technology as dripolene, drip oil or decant oil. They are as a result of the catalytic Cracking of crude oil obtained or can be obtained by steam cracking a material made entirely of naphtha or a Gas oil can be obtained for the production of ethylene / heavy semi-aromatic oils are obtained. However, this does not mean that

709815/1037

pure solvents such as tetralin, decalin or the like, ■ would not be suitable for extracting the coal, but these solvents are more expensive.

The amount of solvent used to dissolve 50% or more of the coal should be between about 0.5 and about 10 parts by weight of the solvent per unit weight of the moisture-free charcoal.

The invention is explained in more detail by means of the accompanying drawings.

Fig. 1 shows a flow diagram of a solvent extraction of coal and the use of the solvent and the coal extract for the production of furnace carbon black. Coal is crushed to a particle size of approximately 0.25 cm or less and mixed with the solvent in a slurry tank. This slurry of coal particles and solvent is then sent to a heated and pressurized extraction zone for a period of time sufficient to dissolve the desired amount of coal. The mixture is then from the extraction zone into a pressure filter press, where the undissolved material, consisting of inorganic Material and ash as well as some undissolved charcoal is separated from the mixture of extracted charcoal and solvent will. The mixture of extracted coal and solvent is passed into a heating zone and then into a soot furnace where natural gas and air are used to produce furnace soot will. The product is then cooled and the soot is collected in first collectors, such as cyclone collectors, whereby if necessary, bag filters can be used as a second collector can. The carbon black is then pulverized and then put into drums for Another use packaged, it can also be powdered, mixed with water and formed into pellets and in suitable Containers for further use.

709815/1037

2 shows two embodiments, according to one embodiment Coal as in Fig. 1 is ground, extracted and filtered. The coal extract and the solvent will be then passed into an evaporator where the solvent is removed from the coal extract and recovered for further use will. The solid coal extract is then fed to a rotary mill. The solid coal particles are also hot Combustion gases mixed at high speed and passed into a soot furnace in which air was used to increase the turbulence used inside the oven. The entrained soot is then quenched and done in the same manner as in Fig. 1 collected either in bulk or in pelletized form. This scheme is the upper part of Fig. 2. The lower part of Fig. shows the recovery of the solid coal extract, which is fed to a rotary mill and reduced to a particle size of 50 to 60 μ is crushed. These coal particles with a particle size of 50 to 60 μ are then used in a high-energy fluid mill fed, where the particles are further reduced to a particle size of approximately 2 to 4 μ using superheated steam be comminuted as grinding fluid. The soot with a particle size of 2 to 4 μ is then either in bulk or in pellet form as collected in Fig. 1.

The following examples illustrate the invention without restricting it. Unless stated otherwise, all parts and percentages relate to weight.

example 1

Bituminous coal turns into particles 0.025 cm in size or marry less. An approximate analysis of the coal in weight% delivers the following values:

7 0 ^C J «15/1037

Moisture 2.1 - - ■

Volatile materials 36.0

Carbon 54.7

Ashes 7.2

The approximate final analysis of the coal in percent by weight is as follows:

Hydrogen 5.2

Carbon 75.5

Nitrogen 1.5

Sulfur 1.5

Ashes 7.2

Oxygen 9.1

1 part by weight of the ground coal is mixed with 2.5 parts by weight of a solvent. The solvent used is a recycled oil obtained from catalytic cracking, which is obtained from the catalytic cracking of crude oil. The solvent is heated ^{to approximately 200 ° C. beforehand.} The hot coal and solvent slurry is then sent to a heat extraction zone. The temperature of the slurry of coal and solvent is increased to approximately 350 ^° C. under autogenous pressure, these conditions being maintained for approximately 30 minutes.

After an extraction period of approximately 30 minutes, the mixture of solvent and charcoal is pumped through a pressure filter. The percentage of extraction of the coal is approximately 65% by weight and is determined by weighing the mineral residue as well as the unextracted carbon remaining in the filter bed is determined.

The hot liquid coal extract and the solvent are obtained as a filtrate and used as a soot generating liquid. These

709815/1037

Liquid is introduced axially into a cylindrical reaction zone of a carbon black furnace through an atomizing spray nozzle which is located located in the central part of the top of the carbon black furnace. The feed takes place at a speed of approximately 207 1 per hour (see. Fig. 1). The atomized liquid starting mixture extracted coal and solvent is thermally decomposed with the help of a turbulent combustion reaction, the maintained by 6 jets of natural gas introduced through 6 separate nozzles equally spaced are arranged concentrically around the atomizing spray nozzle. A stream of air enters the annular space that contains the natural gas nozzles surrounds, by a spiral screw, in the same end of the furnace.

If one works in this way in a furnace, the reaction zone of which is a short cylindrical section with a diameter of about 46 cm and a length of about 23 cm, which is followed by a second short cylindrical section with a diameter of 23 cm and a length of about 23 cm cm, with a total of about 85 standard m ³ per hour of natural gas and about 1510 standard m ^{3 of} air per hour, then a highly structured standard furnace carbon black is obtained in an amount of about 98 kg per hour.

The soot produced has approximately the following properties:

Average particle diameter in S 200-450 surface-N ₂ absorption _r m ² / g 80-130

pH 8-9

oil absorption-m ² / g 1.0-1.5

This example represents the mode of operation according to FIG. 1.

709815/1037

Example 2

A highly volatile bituminous coal with roughly the following analytical values (in% by weight)

Volatile material 39.3

Carbon 47.7

Ash 13.0

becomes particles about 0.025 cm or less in size crushed.

1 part by weight of this ground coal is mixed with 3 parts by weight of a return oil from a catalytic cracker, which has previously been heated ^{to approximately 200 ° C., with stirring.} The hot slurry from cycle oil and ground carbon is pumped into a heated pressure extraction zone, where it is held for a period of about 1 hour at 350 ⁰ C.

The resulting mixture of charcoal extract, undissolved charcoal and solvent is filtered in a pressure filter. The percentage of the coal extract is approximately 75% as judged by the amount of mineral residue as well as the unextracted coal solids is determined.

The hot solid coal extract and the solvent are obtained as a filtrate and used as the furnace soot generating liquid. The material is placed in a vertical furnace of the type shown in Fig. 2 at a rate of approximately 1380 liters per hour Hour introduced. The furnace has 10 cylindrical burner assemblies equally spaced around the furnace chamber along a line approximately 46 cm above the furnace floor. Each cylindrical burner chamber ends in a

709815/1037

- ir $ 1

further tax calculation. Air is introduced into each burner at a rate of approximately 620 standard egg ³ per hour through a tangential feed line. Natural gas is fed to each combustion chamber coaxially through atomizing or spray nozzles at a rate of approximately 54 standard m ³ per hour, as is the soot-generating liquid from the mixture of coal extract and solvent.

This arrangement allows the formation of a rotating ring of flame , which creates an upwardly rising rotating body of combustion gases within the furnace chamber.

The temperature of the furnace chamber is maintained within a range of from 'about 1200 ⁰ C in the vicinity of the bottom of the chamber and about 980 ⁰ C in the vicinity of the upper part of the sections.

Carbon black is produced in such a furnace chamber at a rate of about 1000 kg per hour with a yield of about 1.05 kg of furnace soot per liter of the generating liquid that is fed to the furnace is generated.

The carbon blacks produced in this way have the following on average Features on:

Average particle diameter in A * 220-250

Surface m ² / g 90-110

pH 8-9

Benzene extract, weight% 0.05-0.06

oil absorption, cc / g 1.0-1.4

The carbon blacks produced exert a full reinforcing effect in rubber from, lead to a massive build-up of heat, result in good bending resistance, good resilience and a low one

70 9 815/1037

Continuous deformation - and therefore superior IT work - and Extraction properties, if they are in a corresponding manner to the Rubber -be mixed »This example represents the operation of Fig. 1-

Example 3

A bituminous coal is made up to a size of approximately Grind 0.025 cm or less. The coal has the following approximate Analysis, in% by weight, on;

Moisture 2.1

Volatile materials 26.0

Carbon 54.7

Grayling 7.2

The approximate final analysis, in weight%, is as follows;

Hydrogen 5.2

Carbon 75.5

Nitrogen '1.5

Sulfur 1.5

Oxygen 9.1

Grayling 7.2

1 shows part of the coal is ahlenen solvent under Iffihren with about 2.5 parts by weight, which has been previously to approximately 200 ⁰ C · ^ he hitzt mixed. The solvent is polycyclic hydrocarbons, including aromatic or aaaphthenic hydrocarbons, which are liquid at the temperature and pressure of the extraction, for example tetralin, decalin, biphenyl, methyl aaphthalene, mixtures thereof and a return material from a catalytic cracker.

70981S / 1037

-TJt- * "

This slurry of ground coal in hot solvent is then pumped into a heated extraction zone. The temperature is increased to approximately 350 ^° C. under the autogenous pressure and the mixture is kept under these conditions for a period of approximately 30 minutes.

Then the hot extraction mixture is filtered through a pressure filter filtered. The amount of coal extracted is approximately 65 to 70% as by weighing the mineral residue and the unextracted Coal constituents is determined.

The hot liquid coal extract (piltrate) is then used in an evaporator fed to where the solvent is removed and a solvent recovery system for reuse is fed to extract more coal.

The coal solids obtained in the evaporator are then sent to a rotary mill, where they are reduced to a particle size of less than about 300 mesh.

The pulverized coal is placed in a pyrolysis zone by a hot combustion gas with a temperature of approximately 625 ° C introduced. Heated air is also in the bottom of the vertical Pyrolysis zone introduced.

A Pyrolysezonetemperatur 13QG of about ⁰ C is reached, where a partial decomposition of the extracted coal solids takes place.

The slightly fluffy soot solid particles are released by the product gas into a quenching zone and from there into cyclone collectors and bag filter dragged »Then the collected soot is pelletized. Agglomerates as well as denser particles are removed from the bottom part of the soil and can optionally be used as fuel

709815/1037

can be used to generate hot combustion gas, the in turn is used as a carrier gas.

The carbon black produced has the following composition and properties on:

composition Weight% carbon 92.5 oxygen 1.0 hydrogen 0.5 Volatiles 3.0 physical and chemical properties Weight Average diameter: DnS 400 Surface area, m ² / g 80 pH 8-8.5 Benzene extract,% 0.20 oil absorption, cm ³ / g 1.4-1.6 Nigrometer 85 Coloring power,% SRF 220-230

Experience shows that soot with the above-described Properties is suitable for reinforcing rubber, in particular for reinforcing motor vehicle tires with massive Heat build-up, acceptable flexural strength and good resilience. This example shows the operation of the upper diagram of FIG. 2.

Example 4

The coal extracted according to Example 3 and according to Example 3 as

709815/1037

solid extracted coal reclaimed coal becomes bucket kata—. tion mill fed, in which these materials on a Partial sizes from 5 © to 6 © p. crushed: to be.

This pool with a particle size of 50 to 0 μ is then introduced into a hurricane or flood energy well. A flowing with Scifoallgeselhwindigfceit current AAI überiiitzteBi water vapor imit a temperature of 4 © © 0 to 50 ⁰ C is used "the Teilcihen with a iGrösse of 5 to 6 © © μ amf a daarcli- sdanittliclaeita Diirctanesser of ^ angefäiar 2 to 4 μ to zerkleinern-! This ICreate Koimlepiuilver can then Smit an oxygen-solid imacihenden material, such as zinc stearate, powdered Stearinsäere solid primary amines, or the like SberZogen. Then it can be pelletized.

The Erfaihriiang h.at showed that this material is an excellent semi-reinforcing material for rubber. It has surface areas of around 2 to 25 m ² / g. This example shows how the scheme of the lower part of FIG. 2 works.

7G9P15 / 1Q37

Claims (12)

Claims 'Ί * Process for the production of carbon black, characterized in that that coal is dissolved in a suitable solvent, the solvated coal and the solvent as feed material can be used for a carbon black furnace and the solvated coal and solvent are pyrolyzed to carbon black. 2. The method according to claim 1, characterized in that the solvated coal extract up to a sufficiently small Particle size is milled, whereupon the milled coal extract fed to a carbon black furnace as loading material and the solvated coal is pyrolyzed to carbon black. 3. The method according to claim 1, characterized in that coal is dissolved in a suitable solvent, the solvent is removed from the solvated coal and the solid Grind solvated coal extract to a particle size which is suitable for direct use for certain carbon black applications. 4. The method according to claim 1, characterized in that the The solvent used to dissolve the charcoal is highly aromatic. 5. The method according to claim 2, characterized in that the solvent which is used to dissolve the coal, strongly aromatic, is. 6. The method according to claim 3, characterized in that the solvent which is used to dissolve the coal, is strongly aromatic, 7. The method according to claim 1, characterized in that the 709815/1037 - yr- The solvent used to dissolve the coal is at least one solvent selected from the group consisting of polycyclic hydrocarbons, aromatic hydrocarbons and naphthalenes which ^{boil between approximately 240 and 425 °} C., these materials being subject to temperature and temperature Pressure conditions of coal extraction are liquid. 8. The method according to claim 2, characterized in that the solvent which is used to dissolve the coal, is at least one solvent selected from the group consisting of polycyclic hydrocarbons, aromatic Hydrocarbons and naphthalenes that boil between approximately 240 and 425 ° C, these materials being below the temperature and pressure conditions of coal extraction are liquid. 9. The method according to claim 3, characterized in that the solvent which is used to dissolve the coal, is at least one solvent selected from the group consisting of polycyclic hydrocarbons, aromatic Hydrocarbons and naphthalenes boiling between approximately 240 and 425 ° C, these materials being below the temperature and pressure conditions of coal extraction are liquid. 10. The method according to claim 7, characterized in that the solvent is at least one solvent selected from the group consisting of tetralin, decalin, biphenyl, Naphthalene, return oils from catalytic crackers and dropolin, also known as drip oil or decant oil. 11. The method according to claim 8, characterized in that the solvent is at least one solvent that consists of 709815/1037 is selected from the group consisting of tetralin, decalin, biphenyl, naphthalene, return oils from catalytic crackers and dripoles, also known as drip oil or decant oil. 12. The method according to claim 9, characterized in that the solvent is at least one solvent selected from the group consisting of tetralin, decalin, biphenyl, Naphthalene, return oils from catalytic crackers and dripoles, also known as drip oil or decant oil. 7 Γ - 1 ', / 1 0 3 7