U.S. patent application number 10/865666 was filed with the patent office on 2005-01-27 for process and apparatus for producing carbon blacks.
Invention is credited to Green, Martin C..
Application Number | 20050019246 10/865666 |
Document ID | / |
Family ID | 22212429 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050019246 |
Kind Code |
A1 |
Green, Martin C. |
January 27, 2005 |
Process and apparatus for producing carbon blacks
Abstract
The present invention provides processes for introducing a fluid
stream into a carbon black reactor and for producing carbon black.
According to the present invention, a fluid stream comprising an
oxidant, nitrogen, hydrogen, a hydrocarbonaceous material or
mixtures thereof is introduced into the effluent flowing through a
carbon black reactor in an axial direction.
Inventors: |
Green, Martin C.;
(Boxbrough, MA) |
Correspondence
Address: |
Martha Ann Finnegan, Esq.
Cabot Corporation
157 Concord Road
Billerica
MA
01821-7001
US
|
Family ID: |
22212429 |
Appl. No.: |
10/865666 |
Filed: |
June 10, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10865666 |
Jun 10, 2004 |
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09730708 |
Dec 6, 2000 |
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09730708 |
Dec 6, 2000 |
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PCT/US99/13042 |
Jun 9, 1999 |
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60088620 |
Jun 9, 1998 |
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Current U.S.
Class: |
423/449.1 ;
422/150 |
Current CPC
Class: |
B01J 2219/00159
20130101; B01J 2219/1941 20130101; C09C 1/50 20130101; C01P 2006/19
20130101; B01J 2219/00155 20130101; C01P 2006/12 20130101; B01J
19/2405 20130101 |
Class at
Publication: |
423/449.1 ;
422/150 |
International
Class: |
C09C 001/48 |
Claims
1-10. (canceled)
11. A modular apparatus for producing carbon black comprising: a
combustion zone having an upstream and a downstream end and at
least one port to allow the introduction of a fuel and an oxidant;
a zone of converging diameter having an upstream and a downstream
end and converging from the upstream end towards the downstream
end, the upstream end being connected to the downstream end of the
combustion zone; a transition zone having an upstream and a
downstream end, the upstream end being connected to the downstream
end of the zone of converging diameter, the transition including at
least one port to allow the introduction of a feedstock; an
apparatus for introducing a fluid stream into the reactor in a
direction axial to the flow of a process stream in the reactor, the
apparatus having an upstream and a downstream end, the upstream end
being connected to the downstream end of the transition zone; a
reaction zone having an upstream and a downstream end, the upstream
end being connected to the downstream end of the transition zone or
zones; a quench zone having an upstream and a downstream end, the
upstream end being connected to the downstream end of the reaction
zone, the quench zone including at least one port to allow the
introduction of a quenching fluid; and apparatus for separating and
collecting carbon black connected to the downstream end of the
quench zone or zones.
12. The modular apparatus for producing carbon black of claim 11
wherein the apparatus for introducing a fluid stream into the
reactor in an axial direction comprises a hollow vessel; at least
one inlet for introducing a fluid stream into the interior of the
vessel and an outlet to allow the fluid stream to exit from the
vessel.
13. The apparatus of claim 12 wherein the outlet comprises an
annulus.
14. The apparatus of claim 12 wherein the inlet of the hollow
vessel is disposed radially to the outlet to produce an outlet
fluid stream without significant swirls.
Description
FIELD OF INVENTION
[0001] The present invention relates to new processes and apparatus
for producing carbon blacks.
BACKGROUND
[0002] Carbon blacks may be utilized as pigments, fillers,
reinforcing agents, and for a variety of other applications, and
are widely utilized as fillers and reinforcing pigments in the
compounding and preparation of rubber compositions and plastic
compositions. 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, including iodine adsorption surface area
(I.sub.2 No), nitrogen adsorption surface area (N.sub.2 SA),
dibutyl phthalate adsorption (DBP), dibutyl phthalate adsorption of
crushed carbon black (CDBP), cetyl-trimethyl ammonium bromide
absorption value (CTAB) and Tint value (TINT).
[0003] Carbon blacks may be produced in a furnace-type reactor by
pyrolyzing a hydrocarbon feedstock with hot combustion gases to
produce combustion products containing particulate carbon black. A
variety of methods for producing carbon blacks are generally
utilized.
[0004] In one type of carbon black 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 pyrolysis of the
hydrocarbon feedstock commences with consequent formation of carbon
black. In this instance, pyrolysis refers to the thermal
decomposition of a hydrocarbon. The resulting combustion gas
mixture, in which pyrolysis is occurring, then passes into a
reaction zone where completion of the carbon black forming
reactions occurs.
[0005] Another type of process equipment utilized to produce carbon
blacks is referred to as a modular or staged reactor. Modular
(staged) furnace carbon black reactors are generally described in
U.S. Pat. Reissue No. 28,974 and U.S. Pat. No. 3,922,355, the
disclosures of which are hereby incorporated by reference.
[0006] In certain carbon black production processes a portion of
the overall oxidant introduced in the process is introduced
downstream of the point of feedstock injection. U.S. Pat. No.
4,105,750 discloses a process for producing carbon blacks with
lower structure, as reflected by lower dibutyl phthalate (DBP)
absorption numbers, for a given particle size. In the disclosed
process a portion of the oxidant introduced in the process is
injected at a location downstream of the point of feedstock
injection.
[0007] WO 93/18094 discloses a process for producing carbon blacks
characterized as adding a secondary oxidant stream to the reactor
such that the secondary oxidant stream does not interfere with the
formation of carbon black particles and aggregates in the reactor.
In the disclosed examples the DBP absorption numbers of the carbon
black produced utilizing the secondary oxidant stream were lower
than the DBP absorption numbers of the carbon black produced
utilizing the same reaction conditions in the absence of the
secondary oxidant stream.
[0008] Other patents such as U.S. Pat. Nos. 3,607,058; 3,761,577;
and 3,887,690 also describe the processes for producing carbon
black.
[0009] The temperatures in a carbon black reactor can range between
2400.degree. F. (1315.degree. C.) and 3000.degree. F. (1648.degree.
C.) or greater. The injection of additional oxidant, and/or
secondary air into the reaction stream, for example, in the manner
described in the aforementioned patents, will generally raise the
temperature of the reaction stream, and may raise the temperature
of the reaction stream in the region local to the point of air
injection to well above 3000.degree. F. (1648.degree. C.). This
temperature extreme may cause damage to the refractory lining of
the reactor and/or shorten the useful life of the refractory lining
of the reactor, particularly near the area of additional oxidant
injection.
[0010] Accordingly, it would be advantageous to have a method and
apparatus for adding additional oxidant and/or hydrocarbon
containing fluid streams into the effluent which minimized
refractory problems in the reactor.
[0011] It would also be advantageous to have a method and apparatus
for producing-carbon blacks wherein the introduction of additional
oxidant and/or hydrocarbon containing fluid streams into the
effluent increased the structure of the carbon blacks produced by
the process, as evidenced by the carbon blacks having an increased
DBP absorption value for a given surface area.
[0012] The process and apparatus of the present invention achieve
the aforementioned advantages in addition to other advantages that
will become apparent to those of ordinary skill in the art from the
following description.
[0013] Although general types of furnace carbon black reactors and
processes have been described, it should be understood that the
present invention can be used in any other furnace carbon black
reactor or process in which carbon black is produced by pyrolysis
and/or incomplete combustion of hydrocarbons.
SUMMARY OF THE INVENTION
[0014] The present invention provides processes and apparatus
particularly well suited for use in the production of carbon
blacks.
[0015] An aspect of the present invention are processes and
apparatus for sheathing a gaseous stream. A process for sheathing a
gaseous stream may comprise introducing a fluid stream around the
outer periphery of the gaseous stream. An apparatus for sheathing a
gaseous stream may comprise a hollow vessel, an inlet for
introducing the fluid stream into the interior of the vessel and an
outlet to allow the fluid stream to exit the vessel. The outlet may
comprise an annulus, or a plurality of jets. Preferably the vessel
is annular, i.e. in the shape of a ring, although other shapes are
possible. The annulus or outlet jets may be disposed around the
circumference of the vessel.
[0016] In a further aspect, the present invention provides a
process for producing carbon blacks that includes sheathing the
gaseous stream flowing through the reactor with a fluid stream. The
gaseous stream in a reactor may comprise a combustion gas stream
and/or an effluent stream, formed by introduction of a carbon black
yielding feedstock into the combustion gas stream. The sheathing
preferably occurs after introduction of feedstock into the
combustion gas stream. The fluid stream preferably surrounds the
outer perimeter of a combustion gas stream and/or effluent
disposing the fluid stream between the combustion gas stream and/or
effluent and a reactor wall.
[0017] In a further aspect, the present invention provides
processes for producing carbon black. According to the present
invention a process for producing carbon black includes introducing
a fluid stream in an axial direction into a reactor after the point
of feedstock injection. The fluid stream may be introduced in the
manner described above.
[0018] In another aspect the present invention provides a process
for producing carbon blacks wherein a fluid stream is introduced
into a carbon black reactor after the point of feedstock injection,
the process comprising: introducing the fluid stream in an axial
direction.
[0019] In a process of the present invention the fluid stream may
be added through an annulus or a plurality of jets in the axial
direction. The annulus is concentric to introduce the fluid stream
around a periphery of a process stream. The plurality of jets may
be disposed in a ring or in multiple rings. The axial direction
refers to a direction parallel to the direction of flow of
combustion gases through the reactor. For a cylindrical reactor the
axial direction is generally parallel to the axis of the cylinder.
As used in the process sense, a "jet" refers to a strong
well-defined stream of fluid issuing from an orifice or nozzle.
[0020] These aspects of the present invention, and the features
discussed below provide a means for sheathing the combustion gas
stream and carbon black feedstock mixture (effluent) exiting the
second stage of a modular carbon black reactor. In a preferred
embodiment of the present invention it is generally preferred that
the annulus or jets by which the fluid stream is introduced into
the reactor are disposed so as to surround the effluent stream. As
will be appreciated from the appended figures, the effluent stream
may be surrounded through the introduction of the fluid stream
around the periphery of the gas stream exiting the second stage of
the reactor. The fluid stream introduced into the reactor may be
utilized to at least partially divert the effluent gas stream
exiting the second stage away from the walls of the reactor. In
this manner, heat damage to the refractory lining of the reactor
stage may be minimized.
[0021] In particular, an effect of the fluid stream is to
counteract the tangentially outward spread of the effluent stream
towards the walls of the reactor as the effluent progresses down
the reactor. Accordingly, a function of the fluid stream introduced
into the reactor is to contain or sheath or redirect the effluent
stream so that the temperatures to which the reactor walls are
exposed is reduced. Further, introduction of the fluid stream in
the manner contemplated by the present invention produces a more
uniform mixing than other methods, thereby minimizing high local
temperatures.
[0022] In a further aspect, the present invention provides an
apparatus for introducing a fluid stream into a carbon black
reactor. An apparatus of the present invention for introducing a
fluid stream into a carbon black reactor comprises a hollow vessel,
an inlet for introducing the fluid stream into the interior of the
vessel and an outlet for the fluid stream to exit the vessel.
Suitable outlets include an annulus, a jet, a plurality of jets, or
mixtures thereof. Preferably, an annulus or a plurality of jets are
utilized as an outlet to allow fluid stream to exit the vessel into
the reactor. The vessel may be generally annular (in the shape of a
ring) or another shapes. The annulus may be disposed concentrically
to the inner and outer diameters of the ring, and/or the outlet
jets may be disposed around the circumference of the ring. In
another possible embodiment the outlet jets may be disposed in
concentric circles from an inner portion to the outer periphery of
the vessel. The inlet for the fluid stream may be disposed radially
or substantially parallel to the outlet (annulus or jets) to
produce an exiting fluid stream without significant swirls.
Alternatively, the inlet for the fluid stream may be disposed
tangentially, or substantially tangentially, to the outlet (annulus
or jets) such that the exiting fluid stream includes a tangential
velocity component sufficient to create fluid swirls.
[0023] The processes of the present invention may be practiced with
an apparatus of the present invention, or with other apparatus
known in the art or derivable by those of ordinary skill in the art
based on the disclosure of the present invention.
[0024] In a further aspect the present invention includes an
apparatus for producing carbon blacks comprising the apparatus of
the present invention for introducing a fluid stream. A preferred
apparatus is a modular reactor comprising: a first, or combustion,
stage where an oxidant is contacted with a fuel to produce a stream
of combustion gases at a temperature sufficient to pyrolyze a
carbon black yielding feedstock; a second, or feedstock
introduction, stage where a carbon black yielding feedstock is
introduced into the combustion gases; and a third, or reaction,
stage wherein the mixture of combustion gases and feedstock react
to produce carbon black, the reactor further comprising an
apparatus for introducing a fluid stream into the second or third
stage of the reactor after the point of feedstock injection.
[0025] An advantage of the present invention is that the method of
introduction of the fluid stream will minimize refractory lining
wear generally associated with the introduction of secondary fluid
streams into a reactor.
[0026] A further advantage of the present invention is that the
process for producing carbon blacks of the present invention may be
utilized to produce carbon blacks having increased structure, as
reflected by increased DBP absorption values, for a given surface
area.
[0027] Other advantages of the present invention will become
apparent from the following more detailed description of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 depicts a cross-sectional view of a portion of a
modular furnace carbon black reactor according to an embodiment of
the present invention.
[0029] FIGS. 2a and 2b depict embodiments of apparatus of the
present invention for introducing a fluid stream into a carbon
black reactor.
[0030] FIG. 3 is a cross-sectional view of a portion of the modular
furnace carbon black reactor which was utilized in the Examples
described below.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The present invention provides processes for sheathing a gas
stream in a reactor the processes comprising introducing a fluid
stream around the outer periphery of the gas stream. In a carbon
black production process, the fluid stream is introduced around the
outer periphery of the combustion gas stream and/or effluent
stream. The fluid stream is preferably introduced in an axial
direction, the axial direction referring to a direction
substantially parallel to the overall direction of flow of the gas
stream. The fluid stream may be introduced in a co-current
direction to the direction of flow of the gas stream or introduced
in a counter-current direction. Preferably the fluid stream is
introduced in a co-current direction.
[0032] The present invention also provides processes for producing
carbon black comprising introducing a fluid stream into a gaseous
process stream to sheath the gaseous process stream. In a typical
carbon black reactor, the introduction may occur downstream of the
point of feedstock injection. An embodiment is process for
producing carbon black comprising: introducing a fluid stream to
sheath a process stream after introduction of a feedstock into the
process stream.
[0033] The process may further comprise: introducing the fluid
stream in an axial direction, the axial direction referring to a
direction substantially parallel to the overall direction of flow
of a combustion gas stream/effluent in the reactor. The fluid may
be introduced with or without swirls and co-currently or
counter-currently.
[0034] In a process of the present invention, the introduced fluid
stream is preferably a gaseous stream comprising at least one of
the following components: an oxidant, nitrogen, hydrogen, a
hydrocarbonaceous material or mixtures thereof An "oxidant" as used
herein refers to a composition comprising oxygen, such as
atmospheric air, oxygen-enriched air, combustion products of
hydrocarbon fuels and air and/or oxygen, or mixtures of these
streams. A "hydrocarbonaceous material as used herein refers to a
composition comprising a hydrocarbon such as a hydrocarbon fuel, a
gas stream including an incompletely combusted hydrocarbon fuel,
such as the combustion gas stream from the carbon black production
process, or mixtures of these streams.
[0035] The present invention also provides an apparatus for
practicing the process of the present invention and introducing a
fluid stream in an axial manner. An apparatus of the present
invention comprises: a hollow vessel, preferably a hollow ring, an
inlet or inlets for introducing a fluid stream into the interior of
the vessel and at least one outlet to allow the fluid stream to
exit from the vessel. The outlet may comprise an annulus, or a
plurality of annuli. The outlet may also comprise a jet or a
plurality of jets.
[0036] The inlet may be disposed radially or in an axial direction
substantially parallel to the axial direction of the outlet to
produce an outlet stream without significant swirls. Alternatively
the inlet may be disposed in a direction tangential to the axial
direction of the outlet to produce an outlet stream with swirls.
Further details relating to the process and apparatus for
introducing a fluid stream into a carbon black reactor are set
forth below with reference to the processes and apparatus of the
present invention for producing carbon blacks.
[0037] According to an embodiment of a process of the present
invention, a fluid stream comprising an oxidant, nitrogen,
hydrogen, a hydrocarbonaceous material, or mixtures thereof is
introduced into the effluent flowing through a carbon black reactor
in an axial direction. In one embodiment the fluid stream comprises
atmospheric air, with or without, oxygen enrichment. In another
embodiment, the fluid stream comprises an industrial gas stream
comprising hydrocarbons, hydrogen, carbon monoxide, carbon dioxide
and/or steam. An example of an industrial gas stream is tail gas
from a carbon black production process.
[0038] In one aspect, a process of the present invention for
producing carbon black comprises:
[0039] a) reacting an oxidant, primary fuel, and carbon black
feedstock in a reactor to form an effluent composed of carbon black
and combustion gases;
[0040] b) injecting a fluid stream into effluent in a direction
axial to the direction of the flow of the effluent through the
reactor;
[0041] c) passing the resulting effluent through the reactor;
and
[0042] d) cooling, separating, and recovering the carbon black
product,
[0043] the fluid stream comprising an oxidant, nitrogen, hydrogen,
a hydrocarbonaceous material, or mixtures thereof. The introduction
of the fluid stream preferably results in the production of carbon
blacks having increased structure, as reflected by an increased DBP
absorption value, for a given iodine number (I.sub.2No.) surface
area in comparison to carbon blacks produced utilizing similar
process conditions in the absence of the fluid stream
introduction.
[0044] A process of the present invention may be advantageously
performed in a modular type carbon black reactor including at least
three stages. With reference to this type of reactor, an embodiment
of process of the present invention for producing carbon blacks
comprises:
[0045] generating a stream of combustion gases in a first stage of
a reactor having a velocity sufficient to flow through subsequent
stages of the reactor and a temperature sufficient to pyrolyze a
carbon black yielding feedstock;
[0046] injecting a carbon black yielding feedstock into the
combustion gas in a second stage of the reactor to produce an
effluent composed of carbon black and combustion gases;
[0047] introducing a fluid stream in a direction axial to the flow
of the effluent after the injection of carbon black yielding
feedstock, the resulting effluent passing through the third stage
of the reactor; and
[0048] cooling, separating, and recovering the carbon black
product.
[0049] Preferably the fluid stream is introduced in the third stage
of the reactor, however as will be recognized by those of ordinary
skill in the art the fluid stream may be introduced at any point
subsequent to the introduction of feedstock.
[0050] The fluid stream may comprise an oxidant, nitrogen,
hydrogen, a hydrocarbonaceous material, or mixtures thereof. The
introduction of the fluid stream preferably results in the
production of carbon blacks having increased structure, as
reflected by an increased DBP absorption value, for a given iodine
number (I.sub.2No.) surface area in comparison to carbon blacks
produced utilizing similar process conditions in the absence of the
fluid stream introduction.
[0051] In a "staged" or "modular" reactor, a liquid or gaseous fuel
is reacted with an oxidant, preferably air, in a first stage to
form hot combustion gases. This stage has been referred to the
"burner" stage, the combustion stage and/or the combustion zone of
the reactor.
[0052] The hot combustion gases pass from the first stage,
downstream into an additional reactor stage or stages. Generally
the additional reactor stage(s) includes at least a feedstock
injection stage and a reaction stage. The feedstock injection stage
may be located between the first (or combustion) stage and the
reaction stage and comprise a choke, or zone of restricted
diameter, which is smaller in cross section than the combustion
stage or the reaction stage. The zone of restricted diameter is
also known as the transition zone to those of ordinary skill in the
art.
[0053] In the production of carbon blacks a hydrocarbonaceous
feedstock is injected at one or more points into the path of the
hot combustion gas stream in the feedstock injection stage. 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 hydrocarbonaceous feedstock may be liquid, gas or vapor, and
may be the same as or different from the fuel utilized to form the
combustion gas stream. Generally the hydrocarbonaceous feedstock is
a hydrocarbon oil or natural gas. However, other hydrocarbonaceous
feedstocks such as acetylene are known in the art.
[0054] Following the point of feedstock introduction, the feedstock
is mixed, atomized and vaporized into the combustion gas stream.
The mixture of combustion gases and vaporized feedstock then enters
a stage of the reactor referred to herein as the reaction stage.
Although pyrolysis begins upon injection of the feedstock into the
combustion gas stream, the conversion of vaporized hydrocarbon
feedstock to carbon black primary particles and aggregates
continues in the reaction stage. The residence time of the
feedstock, combustion gases, and carbon blacks in the reaction zone
of the reactor is sufficient, to allow the formation of carbon
blacks. The mixture of combustion gases and carbon blacks in the
reaction zone of the reactor is hereinafter referred to, throughout
the application, as the effluent. After carbon blacks having the
desired properties are formed, the temperature of the effluent is
lowered to stop the major reactions. This lowering of temperature
of the effluent to stop the major reactions may be accomplished by
any known manner, such as by injecting a quenching fluid, through a
quench, into the effluent. As is generally known to those of
ordinary skill in the art, the major reactions are stopped when the
desired carbon blacks have been produced in the reactor, as is
determined by sampling the carbon black and testing for analytical
properties. After the reactions have been stopped and the effluent
sufficiently cooled by any known means, the effluent generally
passes through a bag filter, or other separation system to collect
the carbon black.
[0055] In both types of processes and reactors described above, and
in other generally known reactors and processes, the hot combustion
gases are at a temperature sufficient to effect pyrolysis of the
hydrocarbonaceous feedstock injected into the combustion gas
stream. The temperature of the combustion gas stream prior to
injection of carbon black yielding feedstock is generally at least
2400.degree. F. (1315.degree. C.). After injection of the carbon
black yielding feedstock, the temperature of the process stream
will rise and may reach 3000.degree. F. (1648.degree. C.) or
higher. In view of these temperatures, and the heat generated by
the carbon black production process, reactors for producing carbon
black may include linings made from refractory materials capable of
withstanding the high temperatures.
[0056] A process of the present invention for producing carbon
blacks includes means for sheathing the effluent stream as it
passes through at least a portion of the reactor. By way of
example, with reference to a modular carbon black reactor, a
process of the present invention may comprise:
[0057] generating a stream of combustion gases in a first stage of
a reactor having a velocity sufficient to flow through subsequent
stages of the reactor and a temperature sufficient to pyrolyze a
carbon black yielding feedstock;
[0058] injecting a carbon black yielding feedstock into the
combustion gas stream in a second stage of the reactor to produce
an effluent composed of carbon black and combustion gases;
[0059] sheathing the effluent stream as the effluent stream exits
the second stage of the reactor, the sheathed effluent stream
passing through the third stage of the reactor; and
[0060] cooling, separating, and recovering the carbon black
product.
[0061] The step of sheathing the effluent stream will preferably
divert the effluent stream from the walls of the third stage of the
reactor, at least at the point of initial sheathing. The means for
sheathing the effluent stream may comprise introducing a fluid
stream in a direction axial to the flow of the effluent to surround
the effluent stream exiting the second stage of the reactor.
[0062] A cross-sectional view of a type of reactor in which the
process of the present invention may be practiced is depicted in
FIG. 1. As will be understood, the process of the present invention
does not require any modification of the carbon black reactor,
other than the provision of a means for injecting the
oxidant-containing stream, and therefore may be practiced in other
types of carbon black reactors, such as the types generally
discussed in the Background section.
[0063] One embodiment of a modular apparatus for producing carbon
black of the present invention comprises:
[0064] a combustion zone having an upstream and a downstream end
and at least one port to allow the introduction of a fuel and an
oxidant;
[0065] a zone of converging diameter having an upstream and a
downstream end and converging from the upstream end towards the
downstream end, the upstream end being connected to the downstream
end of the combustion zone;
[0066] a transition zone having an upstream and a downstream end,
the upstream end being connected to the downstream end of the zone
of converging diameter, the transition including at least one port
to allow the introduction of a feedstock;
[0067] an apparatus for introducing a fluid stream into the reactor
in a direction axial to the flow of a process stream in the
reactor, the apparatus having an upstream and a downstream end, the
upstream end being connected to the downstream end of the
transition zone;
[0068] a reaction zone having an upstream and a downstream end, the
upstream end being connected to the downstream end of the
transition zone or zones;
[0069] a quench zone having an upstream and a downstream end, the
upstream end being connected to the downstream end of the reaction
zone, the quench zone including at least one port to allow the
introduction of a quenching fluid; and
[0070] apparatus for separating and collecting carbon black
connected to the downstream end of the quench zone or zones.
[0071] The apparatus for introducing a fluid stream into the
reactor in an axial direction may comprise a hollow vessel; at
least one inlet, preferably a plurality of inlets, for introducing
a fluid stream into the interior of the vessel and an outlet to
allow the fluid stream to exit from the vessel. The outlet may
comprise an annulus, a plurality of annuli, a jet or a plurality of
jets. The inlet(s) of the hollow vessel may be disposed radially or
in an axial direction substantially parallel to the axial direction
of the outlet to produce an outlet fluid stream without significant
swirls. Alternatively, the inlet(s) of the hollow vessel may be
disposed in a direction tangential to the axial direction of the
outlet to produce an outlet fluid stream with swirls.
[0072] FIG. 1 depicts, in cross-sectional view, a modular, also
referred to as a "staged", furnace carbon black reactor of the type
generally disclosed in U.S. Pat. No. 3,922,335, the disclosure of
which is hereby incorporated by reference. FIG. 1 illustrates a
furnace carbon black reactor 2, having a first-stage 10, which has
a zone of converging diameter I 1; a second stage 12; and a third
reactor stage 18. Feedstock 30 is injected at feedstock injection
points 32 in the second stage 12 of the reactor. Quench 40, is
located at point 42 in the third reactor stage 18 to introduce a
quench fluid 50 into the reactor.
[0073] An apparatus of the present invention for introducing a
fluid stream 70 is located downstream of the point of feedstock
injection at point 72. The apparatus 70 includes inlet ports 71 and
an outlet annulus 73 to introduce a fluid stream in an axial
direction into the third reactor stage 18. In the depicted
embodiment inlet ports 71 are disposed substantially parallel to
the outlet annulus 73 to introduce the fluid stream into the
reactor without swirls.
[0074] FIGS. 2a and 2b depict embodiments of an apparatus of the
present invention for introducing a fluid stream into the reactor.
FIG. 2a depicts an end view of an embodiment of an apparatus, 70 of
the present invention for introducing a fluid stream into the
reactor. The view shown is the end including an outlet annulus 73.
In the embodiment shown in FIG. 2, inlet ports 71 are disposed
tangentially to the annulus 73. As a result the annulus will
introduce the fluid stream into the reactor with swirls.
[0075] FIG. 2b depicts an end view of an alternative embodiment of
an apparatus, 70 of the present invention for introducing a fluid
stream into the reactor. The view shown is the end including a
plurality of outlet jets 72. In the embodiment shown in FIG. 2,
inlet ports 71 are disposed tangentially to the outlet jets 72. As
a result the outlet jets will introduce the fluid stream into the
reactor with swirls. In addition, or alternatively, the outlet
apertures for outlet jets 72 may be configured to impart swirl to
the fluid stream.
[0076] FIG. 3 depicts an alternative embodiment of a modular carbon
black reactor for practicing a process of the present invention.
The reactor configuration depicted in FIG. 3 was utilized in the
following examples.
[0077] Referring to FIG. 3, carbon black reactor 3, has a
first-stage 10, which has a zone of converging diameter 11 that
includes a stepped portion; a second, feedstock injection stage 12;
and a third, reactor stage 18. Feedstock 30 is injected at
feedstock injection points 32 in the second stage 12 of the
reactor. Quench 40, is located at point 42 in the third reactor
stage 18 to introduce a quench fluid 50 into the reactor.
[0078] The diameter of the first, combustion stage, 10, up to the
point where the zone of converging diameter, 11, begins is shown as
D-1; the diameter at the step in zone 11 is shown as D-2, and the
diameter of zone 12, as D-3. The length of the first-stage
combustion zone, 10, up to the point where the zone of converging
diameter, 11, begins is shown as L-1; the length of the zone of
converging diameter up to the step is shown as L-2, and from the
step to the beginning of the feedstock injection zone as L-3. The
overall length of the feedstock injection zone is shown as L-4. The
distance between the end of zone 11 and the point of feedstock
injection 32 is shown as F.
[0079] The reactor 3, includes an apparatus of the present
invention for introducing a fluid stream 70 located downstream of
the point of feedstock injection at point 72. The apparatus 70
includes inlet ports 71 and an outlet annulus 73, as depicted in
FIG. 2a, to introduce a fluid stream in an axial direction into the
third reactor stage 1 8. In the depicted embodiment inlet ports 71
are disposed radially to annulus 73 to introduce the fluid stream
into the reactor without swirls. Dimensions of apparatus 70 are
shown as L-5 and L-6.
[0080] In the reactor depicted in FIG. 3 the entrance to the third
reactor stage 18 includes a zone of expanding diameter 19, followed
by a stepped zone 20, a zone of increasing diameter 21 and then a
first zone of uniform diameter 22. After an angled portion of the
reactor there is a second zone of uniform diameter 24.
[0081] D-4 represents internal diameter of the annulus 73 utilized
in the introduction of the fluid stream into the reactor. D-5
represents the external diameter of the annulus 73. The diameter of
zone 19 at its widest point is shown as D-6 and the length of zone
19 as L-7. The diameter of zone 21 at its narrowest point is shown
as D-7 and the length of zone 21 as L-8. The diameter of zone 22 is
shown as D-8 and the length of zone 22 as L-9.
[0082] The length of zone 23 is shown as L-10. The drop at the top
of the reactor between zone 22 and zone 24 is shown as H-1 and the
drop at the bottom of the reactor between zone 22 and zone 24 is
shown as H-2. The diameter of zone 24 is shown as D-9.
[0083] The distance from the start of the third reactor stage 18 to
point 42 where the quench is located is shown as Q.
[0084] Referring to FIG. 1 or FIG. 3, to produce carbon blacks, hot
combustion gases are generated in combustion zone 10 by contacting
a liquid or gaseous fuel with a suitable oxidant stream such as
air, oxygen, mixtures of air and oxygen or the like. Among the
fuels suitable for use in contacting the oxidant stream in
combustion zone, 10, to generate the hot combustion gases are
included any of the readily combustible gas, vapor or liquid
streams such as natural gas, hydrogen, carbon monoxide, methane,
acetylene, alcohol's, or kerosene. It is generally preferred,
however, to utilize fuels having high content of carbon-containing
components and in particular, hydrocarbons. The ratio of air to
fuel varies with type of fuel utilized. When natural gas is
utilized to produce the carbon blacks of the present invention, the
ratio of air to fuel may be from about 10:1 to about 100:1. To
facilitate the generation of hot combustion gases, the oxidant
stream may be preheated.
[0085] The hot combustion gas stream flows downstream from zones 10
and 11 into zones 12 and then 18. The direction of the flow of hot
combustion gases is shown by the arrow in FIG. 1 or 3. Carbon
black-yielding feedstock, 30, is introduced at point 32. The
distance from the end of the zone of converging diameter, 11,
downstream to point 32 is shown as F. In the examples described
herein, carbon black-yielding feedstock, 30, was injected through a
plurality of jets 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 particles and aggregates.
[0086] Suitable for use herein as carbon black-yielding hydrocarbon
feedstocks, which are readily volatilizable under the conditions in
the reactor, are unsaturated hydrocarbons such as acetylene;
olefins such as ethylene, propylene, butylene; aromatics such as
benzene, toluene and xylene; certain saturated hydrocarbons; and
volatilized hydrocarbons such as kerosene's, naphthalene's,
terpenes, ethylene tars, aromatic cycle stocks and the like.
[0087] The mixture of carbon black-yielding feedstock and hot
combustion gases flows downstream through zone 12 into the carbon
black reactor, zone 18. A fluid stream, comprising an oxidant,
nitrogen, hydrogen, a hydrocarbonaceous material, or mixtures
thereof, is introduced into the reaction stream in an axial
direction through apparatus 70 and annulus 73 at the entrance of
reactor stage 18. The fluid stream is introduced under sufficient
pressure to penetrate the interior region of the reactor stage
18.
[0088] Quench 40, located at point 42, injecting quenching fluid
50, is utilized to stop the reactions in the effluent. According to
the process of the present invention, quench 40, is located at a
position 42 which allows reactions in the effluent to occur until
carbon blacks having the desired properties are formed. Q is the
distance from the beginning of zone 18 to quench point 42, and will
vary according to the position of the quench.
[0089] After the mixture of hot combustion gases and carbon black
yielding feedstock is quenched, the cooled gases pass downstream
into any conventional cooling and separating devices 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 may
be, but is not necessarily, followed by some means of
densification, such as pelletization and drying.
[0090] The features and advantages of the present invention are
further illustrated by the following examples.
[0091] The following testing procedures are used in the
determination and evaluation of the analytical properties of the
carbon blacks produced in the examples. Iodine number (I.sub.2 No.)
of the carbon blacks was determined according to ASTM Test
Procedure D1510. The DBP (Dibutyl Phthalate Absorption number) of
the carbon black pellets was determined according to the procedure
set forth in ASTM D3493-86.
EXAMPLES
[0092] Experiments were conducted in a carbon black producing
process in a reactor substantially as described herein, and as
depicted in FIG. 3 with the geometry set forth below. In all
examples, the primary fuel for the combustion reaction was natural
gas supplied to the carbon black forming process at an ambient
temperature of approximately 298 K (77.degree. F.). The liquid
feedstocks utilized in all examples were commercially available
hydrocarbon mixtures.
[0093] A fluid stream comprising combustion air was introduced
without swirl in each example through apparatus 70 and annulus 73.
The reactor geometry and run conditions were as follows:
1 Example 1 2 D-1, cm 19.0 19.0 D-2, cm 14.0 14.0 D-3, cm 10.9 10.9
D-4, cm 15.2 15.2 D-5, cm 18.7 18.7 D-6, cm 33.3 33.3 D-7, cm 76.2
76.2 D-8, cm 91.4 91.4 D-9, cm 68.6 68.6 L-1, cm 61.0 61.0 L-2, cm
30.5 30.5 L-3, cm 14.0 14.0 L-4, cm 27.6 27.6 L-5, cm 1.9 1.9 L-6,
cm 5.0 5.0 L-7, cm 7.6 7.6 L-8, cm 7.6 7.6 L-9, cm 621.0 621.0
L-10, cm 61.0 61.0 H-1, cm 34.3 34.3 H-2, cm 11.4 11.4 F, cm 2.5
2.5 Q, m 10.7 10.7 Point 32, Tips # and Size, 6 .times. 1.32 6
.times. 1.78 mm Feedstock rate, kgh 677 728 Feedstock Temp. C. 176
179 K+ addition, ppm 8 8 Feedstock Total Air, nm.sup.3h 1870 1879
Primary Comb. Air, nm.sup.3h 1832 1315 Primary Comb. Air, 402 402
Temp. C. Primary Nat. Gas, nm.sup.3h 76 54 Primary Nat. Gas Temp.
C. 15 15 Air/Gas Burn Ratio 9.85 9.85 Fluid Injection nm.sup.3h 38
564 Burner Equivalence Ratio 0.40 0.40 Total Equivalence Ratio 4.00
4.18 % Axial Air 2 30 Carbon Black Properties Example 1 Example 2
I2No., m.sup.2/g 30.1 30.0 DBP, cc/100 g 68 74.6
[0094] Examples 1-2 illustrate the effect of fluid stream addition
on the structure of the carbon blacks produced by the process, as
reflected by the DBP of the carbon blacks. As shown in Example 2,
increasing the rate of fluid addition into reactor stage 18 results
in a carbon black having an approximately 10% greater DBP in
comparison to Example 1.
[0095] It should be clearly understood that the forms of the
present invention herein described are illustrative only and are
not intended to limit the scope of the invention. The present
invention includes all modifications falling within the scope of
the foregoing disclosure and the following claims.
* * * * *