EP1287079A2

EP1287079A2 - Manufacture of carbon black using solid fuel source

Info

Publication number: EP1287079A2
Application number: EP01941797A
Authority: EP
Inventors: Roscoe W. Taylor
Original assignee: Cabot Corp
Current assignee: Cabot Corp
Priority date: 2000-06-02
Filing date: 2001-06-01
Publication date: 2003-03-05
Also published as: CN1498251A; AU2001275123A1; WO2001094475A2; WO2001094475A3

Abstract

A process for producing carbon black is provided and includes burning or gasifying a solid fuel and utilizing the heat, hot gases, or hot combustion gases resulting from the burning or gasification to pyrolyze a carbon black-yielding feedstock in a carbon black forming reactor. Through the use of a solid fuel, less hydrogen is produced as compared to the use of conventional hot combustion gas stream fuels and yields of carbon black can therefore be significantly increased. Preferably, a gaseous fuel formed from the gasification of a solid fueld such as coal, coke, petroleum coke, char, combinations thereof, or other solid fuel sources is used to form a hot combustion gas stream. A carbon black-yielding feedstock is injected into the stream of hot gases or heat resulting from the burning or gasifying to yield a stream of hot gases containing carbon black, which is then quenched. The use of a solid fuel source preferably provides a cleaner hot gas stream or heat that produces less deposits and residues than produced from processes using conventional fuels to form a stream of hot combustion gases.

Description

MANUFACTURE OF CARBON BLACK USING SOLID FUEL SOURCE

RAΓKOROTTNII OF THF, TN NTTON The present invention relates to a process for producing carbon blacks wherein a carbon black yielding feedstock is heated to form a carbon black product.

Processes for producing carbon blacks are well known. Many such processes involve the production of a hot combustion gas stream into which a carbon black yielding feedstock is injected under conditions to form a hot combustion gas stream containing carbon black product. The resultant stream is then quenched and the carbon black obtained is separated from the hot combustion gas stream and recovered.

In conventional processes, the hot combustion stream into which the feedstock is injected is formed of a fuel and an oxidant that are together injected into a combustion zone of a reactor. Typically, the fuels mixed with the oxidant to form the hot combustion gases include readily combustible matter such as hydrogen, carbon monoxide, methane, acetylene, alcohols, kerosenes, liquid hydrocarbon fuels, and the like. Typically, it has been preferred to use streams rich in methanes such as natural gas and modified or enriched natural gas, as well as other streams containing high amounts of hydrocarbons such as various hydrocarbon gases, and liquids and refinery bi-products including ethane, propane, butane, pentane, fuel oils, and the like. However, many of these fuels and combinations of these fuels contain or form undesirable deposits or residues that foul the carbon black forming reactor. It is desirable to provide a new source of fuel for combustion gas streams or to provide pyrolizing conditions and carbon black manufacturing processes which form less deposits and residues than are typically formed from conventional fuel sources for hot combustion gas streams. SUMMARY OF THF, PRESENT INVENTION

It is an object of the present invention to provide a process for producing carbon black which utilizes a solid fuel and preferably forms less deposits and residues than are typically formed from conventional fuel sources for combustion gas streams. Through the use of a solid fuel, less hydrogen is produced as compared to the use of conventional hot combustion gas stream fuels and yields of carbon black can therefore be significantly increased.

In accordance with an embodiment of the present invention, a process for producing carbon black is provided wherein a gaseous fuel source obtained from the gasification of a solid fuel is introduced, preferably along with an oxidant, into a combustion zone of a carbon black forming reactor as a hot combustion gas stream. The source of gasified solid fuel preferably forms a low amount of deposits and residues in a carbon black forming reactor.

In accordance with another embodiment of the present invention, a process for producing carbon black is provided wherein a solid fuel source is burned, preferably in the presence of air, to obtain hot gases that are directed through a zone of a carbon black forming reactor to provide conditions that pyrolyze a carbon black-yielding feedstock to form carbon black. Preferably, the burning of the solid fuel produces little hydrogen and thus results in a high yield of carbon black formation.

In accordance with yet another embodiment of the present invention, a process for producing carbon black is provided wherein a solid fuel source is gasified and the resultant gaseous product from the gasification of the solid fuel is directed through a zone of a carbon black forming reactor and provides conditions and temperatures sufficient to pyrolyze a carbon black-yielding feedstock into carbon black.

In accordance with an embodiment of the present invention, a solid fuel source such as coal, coke, petroleum coke, char, combinations thereof, and the like, is gasified by a gasification process to form a gaseous fuel, or burned to provide pyrolyzing conditions useful for the pyrolysis of a carbon black-yielding feedstock to carbon black. The gaseous fuel is preferably then combined with an oxidant in a combustion zone of a carbon black producing reactor to form a hot combustion gas stream into which a carbon black-yielding feedstock is injected. The gaseous fuel resulting from the gasification of a solid fuel may alternatively be used as a hot gas stream without being combusted and directed through a zone of a carbon black-yielding reactor to provide conditions sufficient to pyrolyze a carbon black-yielding feedstock to carbon black. The feedstock is injected under conditions such that a hot gas stream or a hot combustion gas stream containing carbon black is formed, which is then preferably quenched. The carbon black from the resulting stream is then separated and recovered from the gas stream. The use of the gaseous fuel produced from the gasification of solid fuel preferably produces a cleaner burning hot gas stream for pyrolysis and minimizes deposits and residues that accumulate in the carbon black forming reactor relative to the amount of deposits and residues accumulated when conventional fuel sources are used. Also, the yield of carbon black produced is significantly greater, and the present invention also₍ relates to methods of increasing carbon black yields by using one or more of the processes described above.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention, as claimed.

DFTATT FT) DESCRIPTION OF THE PRESENT INVENTION

According to an embodiment of the present invention, a hot gas stream for a carbon black forming reactor includes a gaseous fuel or the combustion product of a gaseous fuel, produced by the gasification of a solid fuel. According to some embodiments of the present invention, a solid fuel is burned, preferably in the presence of a oxidant such as air, and the hot combustion gas resulting from the burning of the solid fuel is directed through a reaction zone of a carbon black forming reactor and provides pyrolysis conditions sufficient to pyrolyze a carbon black-yielding feedstock to carbon black. According to some embodiments of the present invention, a solid fuel is burned, preferably in the presence of an oxidant such as air, and the heat generated from burning the solid fuel is used to pyrolyze a carbon black-yielding feedstock in a reaction zone of a carbon black forming reactor to form carbon black. The solid fuel to be gasified or burned is preferably coal, coke, petroleum coke, char, or combinations thereof, but may be another solid fuel source. Gasification of the solid fuel source typically involves the conversion of the solid fuel to gaseous products by reacting the solid fuel with air, hydrogen, oxygen, steam, carbon dioxide, or a mixture of these components. These components are preferably reacted with the solid fuel in a conventional gasifier. The products that result from the gasification of the solid fuel include carbon dioxide, carbon monoxide, hydrogen, methane, and other chemicals which may typically include hydrocarbons. The ratio of the products resulting from the gasification and the variety of products is dependent upon the particular reactants employed and the temperatures and pressures within the reactors, as well as the type of treatment which the gases from the gasifier undergo subsequent to gasification and/or subsequent to their leaving the gasifier. Herein, the tenn "gasification" includes combustion processes wherein coal, coke, petroleum coke, and/or char is reacted with air or oxygen to produce heat plus carbon dioxide, although such processes have conventionally been referred to as combustion as opposed to gasification. The solid fuel that can be gasified or burned to form heat, a hot gas stream, or a hot combustible gas stream in accordance with embodiments of the present invention is preferably a carbonaceous material. Suitable carbonaceous materials that can be gasified or burned include, but are not limited to, anthracite, bituminous coal, lignite, coke, petroleum coke, waste paper, agricultural waste, and the like. Generally, during gasification, a portion of carbonaceous material is burned to provide the energy for endothermic gasification reactions. However, other heat sources such as nuclear energy, electrical energy, solar energy, and the like, can be used to supply the energy necessary for the solid fuel gasification.

According to preferred embodiments of the present invention, the gasification of the solid fuel is an endothermic reaction. Air or oxygen is preferably supplied to the gasifier to provide the necessary heat input. Gasification of the solid fuel preferably results in the production of either low-BTU or intermediate-BTU gas, which is subsequently used as-is or to form a combustion gas stream in a carbon black production process. According to some embodiments of the present invention, intermediate-BTU gas production can subsequently be upgraded to form ^' synthetic natural gas by using conventional gas-processing steps. Although it is preferable to use solid fuels and process conditions which result in a minimal production of hydrogen gas, the use of solid fuel gasification to provide a combustion gas stream source can provide a source of carbon monoxide and hydrogen building blocks useful in unrelated processes.

Many types of gasifiers can be used to gasify solid fuel and form a hot gas stream or gaseous fuel according to the present invention. One suitable gasifier is a fixed bed gasifier, wherein hot gases are passed through a slowly moving bed of coal. Fluidized bed gasifiers may also be used, wherein small particles of char are fluidized by a stream of gas. Lower temperatures are generally used in fluidized bed gasifiers to prevent softening of coal ash particles. Another suitable type of gasifier is an entrained bed gasifier, wherein fine coal particles are carried by a hot gas stream through a gasification reactor. Entrained bed gasifiers are generally operated at higher temperatures. In addition, coal may also be gasified in place, under ground, by pumping air down one hole, igniting the coal, and drawing the fuel gas up through a second hole, preferably 100 to 1000 feet away.

Preferred gasifiers for use in accordance with the present invention are coal gasifiers. A preferred coal gasifier is a low BTU coal gasifier that uses coal, air, and steam to produce a fuel gas containing 100-120 BTU per cubic foot. Such a low BTU fuel gas contains carbon monoxide, carbon dioxide, hydrogen, water vapor, and nitrogen. Another preferred gasifier is a medium BTU gasifier that uses coal, oxygen, and steam to produce a fuel gas containing about 300 BTU per cubic foot. Such a medium BTU fuel gas contains carbon monoxide, carbon dioxide, hydrogen, and water vapor.

Each of the gasifiers described above are conventional in the art and preferably no special requirements or adaptations are necessary to employ the gasifier in the process of the present invention.

Regardless of the gasification method, the hot gas stream or gas fuel source resulting from the gasification of the solid fuel is employed, according to the present invention, in conventional or non-conventional carbon black manufacturing processes. Preferably, the gaseous fuel resulting from the gasification of the solid fuel source replaces all or some of the liquid fuels conventionally used in the production of a combustion gas stream for the manufacture of carbon black.

According to yet other embodiments of the present invention, a solid fuel is processed by a 5 liquefaction process to produce liquid fuels that are then used in a carbon black manufacturing process as a source of fuel for a combustion gas stream. A wide range of liquid- fuels can be used from solid fuel liquefaction including, for example, heavy fuels, distillate fuel oil, and gasoline. Herein, the phrase "solid fuel gasification" is to be understood to include solid fuel liquefaction, unless indicated otherwise. o The hot gas stream or gaseous fuel used in accordance with embodiments of the present invention can be produced from conventional or non-conventional solid fuel gasification processes. Exemplary gasification processes suitable for the gasification of solid fuels in accordance with the present invention include those processes described in U.S. Patent Nos. 5,676,713; 5,069,685; 4,872,886; 4,785,622; 4,785,621; 4,662,443; 4,378,974; 4,312,638; 3,976,446; and 3,971,639, 5 which are all incorporated herein in their entireties by reference. The gaseous fuel resulting from the gasification process can be stored for use in accordance with the present invention or directly fed or directed to a carbon black forming reactor. If the gaseous fuel resulting from the gasification process is to be burned to form a hot combustion gas stream, the gaseous fuel is preferably fed or directed to a combustion zone of a carbon black forming reactor. If, however, the gaseous fuel o resulting from the gasification process is not to be burned, but rather is to be directly used for the pyrolysis of a carbon black-yielding feedstock to form carbon black, the gaseous fuel is preferably fed or directed to a reaction zone of a carbon black forming reactor.

The gaseous fuels used in accordance with the present invention, which have been produced from a gasification of solid fuels, may replace or be combined with conventional fuel and 5 oxidant compositions used to form a combustion gas stream useful in a carbon black forming reactor. In particular, the gasified fuels used in accordance with the present invention can be used alone or in combination with conventional fuels to form what can be referred to as "a hot gas stream", or if burned, referred to as "a stream of gaseous combustion products", "a stream of hot gases", "a stream of hot first-stages gases", "a combustion gas stream", or "hot combustion gases", into which a carbon black-yielding feedstock is fed in a carbon black forming process.

Exemplary carbon black forming processes which can be adapted to employ the fuel source obtained from gasification or burning of solid fuel in accordance with the present invention include the processes described in U.S. Patent Nos. 3,619,140; Re. 28,974; 3,922,335; 3,952,087; 4,105,750; 4,370,308; 4,374,113; 4,645,657; 4,879,104; 5,093,407; 5,110,576; 5,124,396; 5,137,962; 5,168,106; 5,190,739; 5,211,932; 5,212,226; 5,229,452; 5,232,974; 5,236,992; 5,288,788; 5,352,289; 5,393,821; 5,456,750; and 5,688,317, all of which are incorporated herein in their entireties by reference.

In accordance with embodiments of the present invention, carbon blacks are produced in a carbon black reactor, preferably a furnace carbon black reactor, having a combustion zone and a reaction zone. Hot combustion gases are generated in the combustion zone by contacting a gaseous fuel produced by the gasification of a solid fuel. The gaseous fuel so produced is preferably contacted with a suitable oxidant stream such as air, oxygen, mixtures of air and oxygen, or the like. Preferably, the gaseous fuel produced from the gasification of solid fuel provides a readily combustible gas or vapor stream that includes components such as natural gas, hydrogen, carbon monoxide, methane, acetylene, alcohol, or kerosene. Preferably, the gaseous fuel has a low hydrogen content and a high content of a carbon-containing component, in particular, a high content of hydrocarbons. The ratio of air or oxygen to the fuel utilized to form the hot combustion gases may preferably be from about 10:1 to about 100:1. To facilitate the generation of hot combustion gases, the oxidant stream may be preheated.

The hot combustion gas stream is preferably directed downstream from the combustion zone to a point in the reactor where a carbon black-yielding feedstock is introduced to the hot combustion gases.

According to some embodiments of the present invention, the gaseous fuel resulting from the gasification of a solid fuel are not burned but instead are fed or directed to a reaction zone of a carbon black forming reactor. Under such conditions, the heat of the unburned gaseous fuel, with or without an oxidant such as air, is fed or directed to the reaction zone of a carbon black forming reactor to provide conditions sufficient for the pyrolysis of a carbon black-yielding feedstock in the reaction zone. According to some embodiments of the present invention, a solid fuel is burned and the heat generated from burning the solid fuel, or the hot gases resulting from burning the solid fuel, are fed or directed to a reaction zone of a carbon black forming reactor to provide conditions sufficient for the pyrolysis of a carbon black-yielding feedstock to carbon black in the reaction zone. Suitable for use herein as the carbon black-yielding feedstock are hydrocarbon feedstocks, particularly hydrocarbon feedstocks that are readily volitilizable under the conditions of the reaction. Preferred feedstocks include unsaturated hydrocarbon feedstocks such as acetylene; olefms such as ethylene, propylene, and butylene; aromatics such as benzene, toluene, and xylene; certain saturated hydrocarbons; other hydrocarbons such as kerosenes, naphthalenes, terpenes, ethylene tars, aromatic cycle stocks, and the like; and combinations thereof. Preferably, the carbon black-yielding feedstock is in a liquid form.

According to some embodiments of the present invention, the carbon black-yielding feedstock is injected into the stream of hot gases or hot combustion gases from the inner or outer periphery of the stream. Preferably, the carbon black-yielding feedstock is injected in a direction substantially radial to the flow of the hot gas stream or hot combustion gas stream, and preferably from the inner or outer periphery of the stream.

During the reaction to form the carbon black in accordance with the present invention, various non-conventional process steps or additives may be utilized without departing from the scope of the present invention. For example, the process may include the addition of a second amount of carbon black-yielding feedstock downstream in the reactor from the point where the carbon black-yielding feedstock is initially injected. Steam may also be injected at one or more points along the reactor for the purpose of controlling the morphology of carbon black formed during or from the reaction.

The process of the present invention may include the steps of introducing a gaseous fuel obtained from the gasification of a solid fuel source into a combustion zone or reaction zone of a reactor. The fuel may then be reacted, with or without an oxidant, to provide a stream of hot combustion gases possessing sufficient energy to convert a carbon black-yielding feedstock into carbon black. Alternatively, the gaseous fuel produced from the gasification can be fed directly to the reaction zone of a carbon black-yielding reactor and the heat from the gaseous fuel can be utilized to pyrolyze the carbon black-yielding feedstock. The process also includes injecting a carbon black-yielding feedstock into the stream of hot gases or hot combustion gases. The stream including the carbon black-yielding feedstock is then directed, or flows, through a reaction zone to form a stream of hot combustion gases containing carbon black. The process may also include cooling, separating, and collecting the resultant carbon black. Any suitable means for cooling, separating, and collecting the resultant carbon black may be employed, including means well known to those skilled in the art and described in the patents incorporated by reference above. The present invention also provides an apparatus for the manufacture of carbon black. The apparatus may preferably include conventional carbon black forming reactor components and, in addition, a source of gaseous fuel, hot gases, or heat fonned from the gasification or burning of a solid fuel. More particularly, the apparatus of the present invention preferably provides a carbon black reactor, more preferably, a furnace carbon black reactor, comprising a combustion zone, a reaction zone in communication with said combustion zone, a source of gaseous fuel and/or hot gases, obtained from the gasification or burning of a solid fuel, and a source of a carbon black- yielding feedstock. In addition, the apparatus of the present invention can also include a source of quenching medium for quenching a stream of hot gases or hot combustion gases containing carbon black formed in the reaction zone. Furthermore, the apparatus of the present invention can comprise a cooling device, a separating device, and a collecting device for collecting resulting carbon black formed in the apparatus.

The present invention further involves methods to increase the yield of carbon black fonned by using one or more of the above-described processes, which involves the use of a solid fuel. The processes of the present invention, preferably through the low amounts of hydrogen formed results in the formation of high yield of carbon black formation when the hot gases or heat contacts the carbon black-yielding feedstock in a carbon black fonnation reaction. The yields can be increased by at least 20% and more preferably by at least 50%, and most preferably by at least 75% or more. Also, the use of a solid fuel source is economical since its cost is significantly lower than traditional fuel sources for carbon black formation.

Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof.

Claims

WITAT TS rT.ATMFn TS:

1. A process for producing carbon black comprising: introducing a fuel into a combustion zone, said fuel comprising the gaseous product of a gasification of a solid fuel; reacting the fuel to provide a stream of hot combustion gases possessing sufficient energy to convert a carbon black-yielding feedstock to carbon black; injecting a carbon black-yielding feedstock into the stream of hot combustion gases; flowing the stream of hot combustion gases containing the feedstock through a reaction zone to form a stream of hot combustion gases containing carbon black; and cooling, separating, and collecting the resultant carbon black.

2. The process of claim 1, wherein said solid fuel comprises coal, coke, petroleum coke, char, or a combination thereof.

3. The process of claim 1, wherein said solid fuel is coal.

4. The process of claim 1 , wherein said solid fuel is coke.

5. The process of claim 1, wherein said solid fuel is petroleum coke.

6. The process of claim 1, wherein said solid fuel is char.

7. The process of claim 1, further comprising introducing an oxidant with said fuel into said combustion zone.

8. The process of claim 1 , wherein said carbon black-yielding feedstock comprises a hydrocarbon.

9. The process of claim 1 , further comprising quenching the stream of hot combustion gases containing carbon black prior to cooling, separating, and collecting the resultant carbon black.

10. A process for producing carbon black comprising: introducing a stream of hot gases into a reaction zone of a carbon black fonning reactor, said stream of hot gases comprising the hot gaseous product of a gasification of a solid fuel and possessing sufficient energy to convert a carbon black-yielding feedstock to carbon black; injecting a carbon black-yielding feedstock into the stream of hot gases; flowing the stream of hot gases containing the feedstock through the reaction zone to form a stream of hot gases containing carbon black; and 5 • cooling, separating, and collecting the resultant carbon black.

11. The process of claim 1, wherein said solid fuel comprises coal, coke, petroleum coke, char, or a combination thereof.

12. A process for producing carbon black comprising: burning a solid fuel to form heat and hot gases; 0 directing the heat or hot gases or both into a reaction zone of a carbon black forming reactor; injecting a carbon black-yielding feedstock into the reaction zone and heating the feedstock with said heat or hot gases; flowing the feedstock through the reaction zone to form a carbon black-containing 5 stream; and cooling, separating, and collecting the resultant carbon black.

13. ' The process of claim 12, wherein said solid fuel comprises coal, coke, petroleum coke, char, or a combination thereof.

14. The process of claim 12, wherein said burning of said solid fuel forms a stream of hot o combustion gases; said carbon black-yielding feedstock is injected into the stream of hot combustion gases; and said process further comprising directing the stream of hot combustion gases containing the feedstock through the reaction zone to form a stream of hot combustion gases containing 5 carbon black prior to cooling, separating, and collecting the resultant carbon black.

15. An apparatus for producing carbon black, comprising a reactor having a reaction zone; a source of fuel comprising a solid fuel; an injection device to inject heat, a combustion product of said solid fuel, or a gasification product of said solid fuel, into said combustion zone; a source of carbon black-yielding feedstock; and an injection device for injecting the source of carbon black-yielding feedstock into the reaction zone.

16. The apparatus of claim 15, further comprising a cooling device for cooling a stream of hot gases containing carbon black formed in said reaction zone.

17. The apparatus of claim 16, further comprising a separating device for separating carbon black from a stream of gases containing the carbon black.

18. The apparatus of claim 17, further comprising a collecting device for collecting separated carbon black.

19. The apparatus of claim 15, further comprising a quenching device to quench a stream of hot gases containing carbon black formed in said reaction zone.