Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Pigment or carbon black producer
Reexamination Certificate
1997-09-12
2002-11-26
Knode, Marian C. (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Pigment or carbon black producer
C422S150000, C422S152000, C422S156000, C422S158000, C423S449100, C423S449900, C423S450000, C423S451000, C423S456000, C423S457000
Reexamination Certificate
active
06485693
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a new process and apparatus for producing furnace carbon blacks.
BACKGROUND
Carbon blacks are widely utilized as pigments in ink compositions, paints and the like; as fillers and reinforcing pigments in the compounding and preparation of rubber compositions and plastic compositions, and for a variety of other applications. Carbon blacks are generally characterized on the basis of their properties including, but not limited to, their surface areas, surface chemistry, aggregate sizes and particle sizes. The properties of carbon blacks are analytically determined by tests known to the art.
Carbon blacks are generally produced in a furnace-type reactor by reacting a hydrocarbon feedstock with hot combustion gases to produce combustion products containing particulate carbon black. In the carbon black literature, this reaction between the combustion gases and the hydrocarbon feedstock is generally referred to as pyrolysis.
A variety of methods for producing carbon blacks are generally known. In one type of a carbon black furnace reactor, such as shown in U.S. Pat. No. 3,401,020 to Kester et al., or U.S. Pat. No. 2,785,964 to Pollock, hereinafter “Kester” and “Pollock” respectively, a fuel, preferably hydrocarbonaceous, and an oxidant, preferably air, are injected into a first zone and react to form hot combustion gases. A hydrocarbon feedstock in either gaseous, vapor or liquid form is also injected into the first zone whereupon reaction of the hydrocarbon feedstock commences. The resulting combustion gas mixture, in which the reaction is occurring, then passes into a reaction zone where completion of the carbon black forming reaction occurs.
In another type of carbon black furnace reactor a liquid or gaseous fuel is reacted with-an oxidant, preferably air, in the first zone to form hot combustion gases. These hot combustion gases pass from the first zone, downstream through the reactor, into a reaction zone and beyond. To produce carbon blacks, a hydrocarbonaceous feedstock is injected at one or more points into the path of the hot combustion gas stream. The hydrocarbonaceous feedstock may be liquid, gas or vapor, and may be the same or different than the fuel utilized to form the combustion gas stream. Generally the hydrocarbonaceous feedstock is a hydrocarbon oil or natural gas. The first (or combustion) zone and the reaction zone may be divided by a choke or zone of restricted diameter which is smaller in cross section than the combustion zone or the reaction zone. The feedstock may be injected into the path of the hot combustion gases upstream of, downstream of, and/or in the restricted diameter zone. The hydrocarbon feedstock may be introduced in atomized and/or non-pre atomized form, from within the combustion gas stream and/or from the exterior of the combustion gas stream. Carbon black furnace reactors of this type are generally described in U.S. Reissue Pat. No. 28,974, to Morgan et al., and U.S. Pat. No. 3,922,335, to Jordan et al., the disclosure of each being incorporated herein by reference.
In generally known reactors and processes, the hot combustion gases are at a temperature sufficient to effect the reaction of the hydrocarbonaceous feedstock injected into the combustion gas stream. In one type of reactor, such as disclosed in Kester, feedstock is injected, at one or more points, into the same zone where combustion gases are being formed. In other type reactors or processes, the injection of the feedstock occurs, at one or more points, after the combustion gas stream has been formed. The mixture of feedstock and combustion gases in which the reaction is occurring is hereinafter referred to, throughout the application, as “the reaction stream”. The residence time of the reaction stream in the reaction zone of the reactor is sufficient to allow the formation of desired carbon blacks. In either type of reactor, since the hot combustion gas stream is flowing downstream through the reactor, the reaction occurs as the mixture of feedstock and combustion gases passes through the reaction zone. After carbon blacks having the desired properties are formed, the temperature of the reaction stream is lowered to a temperature such that the reaction is stopped.
U.S. Pat. No. 4,327,069, to Cheng (“Cheng '069”), and its divisional, U.S. Pat. No. 4,383,973, to Cheng (“Cheng '973”), disclose a furnace and a process for producing carbon black having a low tint residual utilizing two carbon black reactors. “Each of the carbon black reactors has a precombustion section, a reaction section, hydrocarbon inlet means, and hot combustion gas inlet means”. Cheng '973, Col. 4, 11. 16-19. One of the reactors is a high-structure carbon black reactor, and the other reactor is a low-structure carbon black reactor. Cheng '973, Abstract. “A second flow of hot combustion gases formed by the combustion of a second fuel stream and a second oxygen containing stream is established in the second carbon black forming zone. A second stream of hydrocarbon feedstock is introduced into the second carbon black forming zone of the furnace into admixture with the second flow of hot combustion gases established therein as well as with the first carbon black forming mixture coming from the first carbon black forming zone of the furnace.” Cheng '973, Col. 2, 11. 19.
SUMMARY OF THE INVENTION
I have discovered that it is possible to reduce the amount of fuel utilized to produce carbon black by reacting the reaction stream of a prior carbon black forming process with an oxidant to generate a stream of combustion products that will react with carbon black yielding feedstock to produce carbon black. The generation of this stream of combustion products may be accomplished by introducing any suitable oxidant, which may be any oxygen containing material such as air, oxygen, mixtures of air and oxygen, or other like materials into the reaction stream. The resulting stream of combustion products is reacted with additional carbon black yielding feedstock to produce carbon black. As a result, the amount of fuel utilized for producing carbon black is reduced.
Accordingly, the process of the present invention is a process for producing carbon black comprising:
reacting a reaction stream formed by a prior carbon black forming process with an oxidant and a carbon black yielding feedstock to produce carbon black; and
cooling, separating and recovering the carbon black. Preferably, the process further comprises:
forming the reaction stream by a process comprising reacting a fuel with an oxidant and a carbon black yielding feedstock; and
reacting the reaction stream with oxidant and carbon black yielding feedstock under conditions that reduce the amount of fuel utilized to produce the total amount of carbon black produced by the process. The fuel reduction is observed in the amount of fuel utilized per pound of carbon black produced by the process when compared to the amount of fuel utilized per pound of carbon black to form the reaction stream. More particularly, the amount of fuel utilized, per pound of carbon black, to produce the total amount of carbon black produced by the process, is less than the amount of fuel, per pound of carbon black, utilized to produce a carbon black, of not less than substantially the same CTAB surface area, by the process which formed the reaction stream. If one operates a typical carbon black producing process to produce a carbon black of a given CTAB surface area, and, prior to cooling, separating and recovering the carbon black, reacts the reaction stream with an oxidant and carbon black yielding feedstock, according to the process of the present invention, it is possible and practicable to produce more total carbon black of not less than substantially the same CTAB surface area at a lower specific fuel consumption (BTU/pound of carbon black) than the typical carbon black forming process preceding the reaction between the reaction stream and the oxidant and carbon black yielding feedstock. Preferably, the reduction in
Cabot Corporation
Knode Marian C.
Ridley Basia
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