Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/44—Carbon
  • C09C1/48—Carbon black
  • C09C1/50—Furnace black ; Preparation thereof

Definitions

• the present invention relates to a novel and improved furnace process for easily and steadily producing carbon blacks having lower specific surface area and structure levels than it is possible to produce in a conventional furnace carbon black process.
• the carbon blacks produced by the process of the present invention are suitable for various applications including fillers, reinforcing agents and color pigments in rubbers and plastics.
• liquid hydrocarbon feedstock is pyrolyzed by a hot primary combustion gas stream generated from a mixture of fuel and oxidant, such as preheated air or the like, to form an effluent stream. Pyrolysis of the feedstock is stopped by a quench and carbon black products are separated and recovered from the quenched gas stream.
• the specific surface area of carbon black produced by furnace process depends, generally, upon decomposition reaction temperature which is controlled by primary combustion gas temperature and the amount of feedstock introduced.
• the specific surface area of carbon black decreases with falling reaction temperature, which decreases with falling primary combustion gas temperature and with an increase in the amount of feedstock introduced.
• temperature of the primary combustion gas cannot be decreased without any limitation, because the primary combustion gas supplies energy for decomposition of the feedstock. Therefore, production of carbon blacks having such a low specific area in furnace process is generally accomplished by increasing the amount of feedstock introduced which leads to a need to shut down the reactor for cleaning as a result of carbon black adhering to the inside of the reactor walls as indicated by low light transmittance of toluene discoloration.
• the reaction zone may be expanded but expansion of the reaction zone may lead to a new problem of accumulation of carbon black formed due to slowdown of effluent gas speed in the reactor and also an undesirable economic problem associated with the need for enlarged facilities.
• Primary particle diameter of the carbon black is generally dependent upon the reaction temperature. The higher the reaction temperature, the smaller is the primary particle diameter of the carbon black formed. The higher the structure of a carbon black, the lower is the specific area of the carbon black at a given particle size. This means that low structure blacks have higher specific surface area at a given primary particle size than high structure blacks.
• U.S. Patent No. 5,190,739 gives important suggestions of production method of carbon blacks having both low structure and low specific surface area at a given overall combustion level, which gives an important suggestion to a method for preparing carbon blacks having both low structure and low specific surface area at a given feedstock level introduced.
• This method is carried out by adding an auxiliary hydrocarbon such as an auxiliary hydrocarbon having high molar hydrogen-to-carbon ratio or hydrogen.
• an object of the present invention is to develop an improved furnace carbon black process in order to produce easily and steadily carbon blacks having both low specific surface area and low structure which have been regarded as being difficult to produce by conventional furnace process.
• furnace carbon black process featuring restraint both of specific surface area and structure developments by means of introduction of steam at or near the position of introduction of feedstock in furnace carbon black process.
• steam is introduced into the combustion gas stream at, or near (upstream or downstream), the point of the injection of the hydrocarbon feedstock into the gas stream such that the ratio L/D (as hereinafter defined) ranges from 0 to less than 1.0.
• Figure 1 is a cross-sectional view of a portion of one type of furnace carbon black reactor which may be utilized to perform the process of the present invention.
• Figure 1 illustrates a carbon black reactor having combustion zone, 1 where fuel from probe 2, and an oxidant, such as air or the like, circulating in space 3, are reacted to form a hot combustion gas stream.
• fuels suitable for use in contacting the oxidant stream in combustion zone 1 to generate the hot combustion gases are any of the readily combustible gas, vapor, or liquid streams such as natural gas, hydrogen, carbon monoxide, methane, acetylene, alcohol, or kerosene. It is generally preferred, however, to utilize fuels having a high content of carbon-containing components and in particular, hydrocarbons.
• the ratio of air to natural gas utilized to produce the carbon blacks of the present invention may preferably be from about 10: 1 to about 100: 1.
• the oxidant stream may be preheated.
• the direction of the flow of hot combustion gases is shown in the figure by the arrow.
• the hot combustion gas stream travels from zone 1, downstream into a transition zone, 20 having a diameter "D".
• a liquid hydrocarbon feedstock is introduced at point 4 in zone 20.
• Suitable for use herein as carbon black-yielding hydrocarbon feedstocks which are readily volatilizable under the conditions of the reaction, are unsaturated hydrocarbons such as acetylene; olefins such as ethylene, propylene, butylene; aromatics such as benzene, toluene and xylene; certain saturated hydrocarbons; and other hydrocarbons such as kerosenes, naphthalenes, terpenes, ethylene tars, aromatic cycle stocks and the like.
• carbon black-yielding feedstock is injected in the form of a plurality of streams which penetrate into the interior regions of the hot combustion gas stream to insure a high rate of mixing and shearing of the hot combustion gases and the carbon black-yielding feedstock so as to rapidly and completely decompose and convert the feedstock to carbon black.
• Quench 5 located in zone 30 injects a quenching fluid, such as water to stop the reaction when carbon blacks having the desired properties are formed.
• the location of quench 5 may be determined in any manner known to the art for selecting the position of a quench to stop pyrolysis.
• One method for determining the position of the quench to stop pyrolysis is by determining the point at which an acceptable toluene extract level for the carbon black is reached. Toluene extract level may be measured by using ASTM Test D1618-83 "Carbon Black Extractables - Toluene Discoloration *1 .
• S 1 is the distance from point of fuel introduction through probe 2, to the point of feedstock introduction at point 4.
• S2 is the distance from the point of feedstock introduction, point 4, to the quench 5.
• S3 is the distance from quench 5 to the end of zone 30.
• the cooled gases pass downstream into any conventional cooling and separating means whereby the carbon blacks are recovered.
• the separation of the carbon black from the gas stream is readily accomplished by conventional means such as a precipitator, cyclone separator or bag filter. This separation may be followed by pelletizing using, for example, a wet pelletizer.
• combustion zone 1 of the first section hot primary combustion gas is generated by mixing and reaction of fuel from probe 2, with oxidant in space 3, such as preheated air or the like.
• oxidant in space 3, such as preheated air or the like.
• second zone (S2) adjacent to the first section pyrolysis of feedstock, formation of precursor of carbon black and growth of primary particle of carbon black advance, subsequently to the introduction of liquid hydrocarbon feedstock into the primary combustion gas stream.
• the effluent is quenched by cooling medium from quench 5 such as water or the like to terminate the reaction and produce carbon black.
• the distance (L) from the position of introduction of feedstock to that of introduction of steam, upstream or downstream, from the position of feedstock introduction must be smaller than diameter (D) of the throat where feedstock is introduced such that L/D ranges from 0 to less than 1.0.
• the diameter of the throat into which feedstock is introduced is generally optimized according to intrinsic factor for individual reactor in a furnace carbon black process. Regardless of the shape of the reactor, the same results are obtained in all cases of steam introduction wherein L/D ranges from 0 to less than 1.0.
• the amount of steam introduced is less than 1% by weight of feedstock introduced, the effect of steam introduction on restraint both of specific surface area and structure of carbon black is slight.
• the degree of restraint of specific surface area and structure development of carbon black is approximately proportional to the increase of steam level introduced.
• the amount of steam introduced into the combustion gas stream ranges from 1 to 15%, by weight, of the amount of feedstock introduced.
• Iodine Absorption No. This was determined in accordance with JIS K-6221 for Example I and in accordance with ASTM D1510 for Example II.
• DBP Diabutyl Phthalate Absorption No.: This was determined in accordance with JIS K-6221 for Example I and in accordance with ASTM D3493 for Example II.
• Compressed DBP Absorption No. was determined after compression treatment of four times repeated by 24,000 psi load. This was determined in accordance with ASTM D3493 for Example I.
• This Example illustrates the process of the present invention wherein LJD is greater than 0, and less than 1.0, in comparison to processes without steam introduction.
• Limit Specific Surface Area index demonstrates directly the effect of steam introduction on restraint of specific surface area, it proves, for instance referring to actual examples, that the introduction of about 3% steam can restrain specific surface area at least by about 14 m 2 /g or more.
• This Example illustrates the process of the present invention wherein L/D equals 0, in comparison to processes without steam introduction.
• the effluent was quenched through the use of a quench located 5.44 meters from the point of feedstock introduction.
• Air Preheat oC 482 482 482 Fuel Rate (kg hr) 12.2 12.2 12.2 Feedstock Rate (kg/hr) 115.7 115.7 115.7 Primary Combusion % 250 250 250 Overall Combustion % 28 28 28
• Example Runs 7 and 8 of the process of the present invention As also shown in Table 5, by a comparison of the results for Example Runs 7 and 8 of the process of the present invention, increasing the rate of steam introduction, results in a greater decrease in surface area and structure.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)

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• 1995
  • 1995-05-04 CA CA002220047A patent/CA2220047A1/en not_active Abandoned
  • 1995-05-04 WO PCT/US1995/005104 patent/WO1996034918A1/en not_active Application Discontinuation
  • 1995-05-04 EP EP95918853A patent/EP0824572A4/en not_active Withdrawn
  • 1995-05-04 HU HU9801418A patent/HUT77871A/hu unknown
  • 1995-05-04 CZ CZ19973479A patent/CZ291549B6/cs not_active IP Right Cessation
  • 1995-05-04 AU AU24487/95A patent/AU708989B2/en not_active Ceased

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