Process for producing carbon black

A process for producing carbon black comprises combustion of a fuel with air to form a stream of products of complete combustion of the fuel, whereinto a hydrocarbon feedstock is then added. The hydrocarbon feedstock is decomposed by absorption of heat from the combustion products, with the formation of a carbon black containing effluent. A portion of the carbon black containing effluent is collected and the remaining portion of the carbon black containing effluent is quenched by introducing a cooling agent thereinto. Thereafter carbon black is recovered from the remaining portion of the carbon black containing effluent. The collected portion of the carbon black containing effluent is fed, according to the invention, into the combustion chamber as fuel.

The present invention relates to the production of compositions of matter 
by way of thermal or thermal-oxidative decomposition of a hydrocarbon 
feedstock and, more particularly, to a process and apparatus for the 
production of carbon black. 
The present invention can find its most successful use in the production of 
oil furnace carbon black employed as a reinforcing filler in the 
manufacture of tires and industrial rubber goods. 
Known in the art is a process for producing carbon black by way of thermal 
decomposition of a liquid hydrocarbon feedstock. The process involves 
burning the fuel in the presence of oxygen to form a high-temperature 
stream of total combustion products. A hydrocarbon feedstock is fed into 
the stream of products resulting from total combustion of the fuel, and is 
decomposed by absorbing the heat from the combustion products, to form a 
carbon black containing effluent. 
Thereafter, the carbon black containing effluent is quenched by passing a 
cooling agent therethrough and carbon black is separated from the reaction 
gases. A portion of the reaction gases is cooled to condense water vapor 
contained therein and then fed into combustion chamber as a fuel. 
An apparatus intended for carrying-out said prior art process for producing 
carbon black is composed of a combustion chamber and a reaction chamber 
successively mounted and communicating therebetween. The combustion 
chamber is provided with means for supplying oxygen and a portion of 
reaction gases, wherefrom water vapor is removed by cooling. The reaction 
chamber is provided with a nozzle for the feedstock supply and at least 
one nozzle for the supply of a cooling agent. The combustion chamber and 
the reaction chamber are formed by a refractory lining provided in the 
reactor housing (cf. U.S. Pat. No. 2,672,402 Cl. 23-209.8). 
The prior art process for producing carbon black using the above-described 
apparatus, necessitates high expenses for cooling a portion of the 
reaction gases and its subsequent heating in the combustion chamber. The 
metal means for cooling the portion of the reaction gases fed afterwards 
into the combustion chamber as a fuel, rapidly deteriorates. 
Known is a process for producing carbon black which comprises combustion of 
a fuel with air in substantial excess of the stoichiometric to form a 
stream from products of the complete combustion of the fuel. A hydrocarbon 
feedstock is then fed into the stream of the products of the complete 
combustion of the fuel. The hydrocarbon feedstock is decomposed by 
absorption of heat from the hot combustion gases with the formation of the 
carbon black containing effluent. A portion of the carbon black containing 
effluent is collected and recycled to the decomposition zone of the 
hydrocarbon feedstock. Recycle of the carbon black containing effluent is 
effected by injection with the stream of products resulting from complete 
combustion of the fuel. The remaining portion of the carbon black 
containing effluent is quenched by injecting cooling water thereinto. 
Afterwards, carbon black is recovered from the carbon black containing 
effluent. 
An apparatus for carrying out this prior art process for producing carbon 
black consists of a combustion chamber and a reaction chamber successively 
mounted within a hollow housing of the reactor and communicating with each 
other. The reactor has a pipe for collection of the carbon black 
containing effluent from the reaction chamber and injection thereof into 
the initial down-stream part of the reactor into the feedstock 
decomposition zone. The combustion chamber is provided with means for 
supplying fuel and air, as well as a nozzle for feeding the feedstock 
thereinto. 
The reaction chamber is provided with a nozzle for the supply of a cooling 
agent. One end of the pipe for collection of the carbon black containing 
effluent is connected with the last downstream part of the reaction 
chamber and positioned prior to the nozzle for the supply of the cooling 
agent. Another end of the pipe is connected with the initial downstream 
part of the reaction chamber of the apparatus (cf. U.S. Pat. No. 3,645,685 
Int.Cl. C 09 c 1/50). 
In this prior art process and apparatus for producing carbon black the 
amount of air applied into the combustion chamber of the reactor for 
burning the fuel is substantially higher than the stoichiometric value 
(150%). The result is that the products of complete combustion contain 
free oxygen which reacts with a portion of the hydrocarbon feedstock to 
form carbon monoxide and carbon dioxide. As a result, the total yield of 
carbon black is insufficient. 
The total yield of carbon black means the yield of carbon black as 
calculated per total mass of the feedstock and hydrocarbon fuel employed 
in the process. The yield of carbon black per total mass of the fuel and 
feedstock is the most objective measure of the process efficiency taking 
into account a recent price increase for natural and petroleum gases as 
well as for liquid feedstock of petroleum origin. Due to this price 
increase, the share of expenses for the hydrocarbon fuel has increased 
considerably and is comparable with expenses for the feedstock. 
Furthermore, in the prior art process for producing carbon black, during 
the supply of the collected portion of the carbon black containing 
effluent into the feedstock decomposition zone, the carbon black formation 
process in the feedstock decomposition zone occurs in the presence of 
carbon black which is present in the collected portion of the carbon black 
containing effluent. 
The result, on one hand, is an decreased dispersion and decreased degree of 
structure of the carbon black obtained and, on the other hand, increased 
polydispersity of carbon black which is undesirable from the point of view 
of mechanical properties of rubber mixes containing this carbon black as a 
filler. 
The term "dispersion" of carbon black means the particle size of carbon 
black; the term "degree of structure" means the degree of agglomeration of 
carbon black particles to aggregates. 
The term "polydispersity" of carbon black means size distribution of carbon 
black particles. 
Furthermore, in the above-described prior art reactor it is rather 
difficult to control the amount of the collected portion of the carbon 
black effluent, since collection of this portion is effected by means of 
injection with the stream of combustion products supplied from the 
combustion chamber to the reaction chamber. 
It is the main object of the present invention to provide a process for 
producing carbon black and an apparatus to ensure production of carbon 
black having a high degree of structure. 
Another important object of the present invention is to provide a process 
for producing carbon black and an apparatus to ensure a relatively high 
total yield of carbon black. 
It is still another object of the present invention to provide a process 
for producing carbon black and an apparatus which makes it possible to 
control the amount of the collected portion of the carbon black containing 
effluent. 
These objects are accomplished by a process for producing carbon black, 
wherein a fuel is combusted with air to form a stream of products from the 
complete burning of the fuel. Thereafter a hydrocarbon feedstock is 
introduced into the stream of products of the complete combustion of the 
fuel and a carbon black containing effluent is formed by thermal 
decomposition of the hydrocarbon feedstock in the stream of products of 
the complete combustion of the fuel. A portion of the carbon black 
containing effluent is collected, and the remaining portion of the carbon 
black containing effluent is quenched by introducing a cooling agent 
thereinto. The carbon black is then recovered from the remaining portion 
of the carbon black containing effluent. In accordance with the present 
invention, the collected portion of the carbon black containing effluent 
is injected into the combustion zone as a fuel. 
The use of high-temperature carbon black containing effluent as a fuel 
makes it possible to reduce the amount of hydrocarbon fuel with high 
heating value or completely eliminate same from the process. As a result, 
the process efficiency is increased due to an increased total yield of 
carbon black. The degree of structure of the resulting carbon black is 
also increased. 
On the other hand, the use of the carbon black containing effluent as a 
fuel with a heating value substantially lower than that of the hydrocarbon 
fuel makes it possible to reduce the amount of excess air supplied into 
the combustion chamber. The supply rate of air approaches the 
stoichiometric value, while the temperature in the combustion chamber is 
not high enough to threaten the stability of the refractory lining of the 
combustion chamber. 
Furthermore, the supply of high-temperature carbon black containing 
effluent as a fuel into the combustion chamber makes it possible to 
utilize its physical heat for decomposition of the hydrocarbon feedstock. 
As a result, the total yield of carbon black is increased. 
It is preferable that the collected portion of the carbon black containing 
effluent being fed into the combustion zone be of from about 2 to about 
26% by volume. 
The minimum amount (2% by volume) of recycled carbon black containing 
effluent is defined by the necessity of ensuring an adequate amount of 
heat for decomposition of the hydrocarbon feedstock. 
Increasing the amount of recycled carbon black containing effluent above 
26% by volume will have a minimal effect on the total carbon black yield 
due to the increase in the amount of carbon black burnt in the combustion 
chamber. 
It is preferable that the portion of the carbon black containing effluent 
being fed into the combustion chamber be injected with air under a 
pressure of from 5 to 10 atm.g. 
This improves the conditions of burning the recycled portion of the carbon 
black containing effluent. 
Furthermore, the use of compressed air for the supply of the collected 
portion of the gas-carbon products makes it possible to easily control the 
amount of this portion. The limits of variation in the air pressure 
correspond to optimal conditions of operation of the injection means. 
The above-mentioned objects of the present invention are also accomplished 
by an apparatus for carrying out the process for producing carbon black 
which comprises a hollow housing communicating with a combustion chamber 
with means for the supply of a fuel and air thereinto and a reaction 
chamber with at least one nozzle for the supply of a cooling agent and at 
least one nozzle for the supply of a hydrocarbon feedstock into the stream 
of products of complete combustion of the fuel, and at least one pipe 
communicating with the cavity of the apparatus housing and intended for 
collection of a portion of the carbon black containing effluent from the 
reaction chamber and introduction thereof into the cavity of the apparatus 
housing prior to the collection zone. In accordance with the present 
invention, one end of the pipe is positioned before the nozzle for the 
cooling agent supply, while the other end is connected to the combustion 
chamber, and an injection means is provided communicating with said pipe 
and mounted in the vicinity of said other end thereof. 
The connection of the other end of said pipe for collection of a portion of 
the carbon black containing effluent to the combustion chamber through an 
injection means makes possible for supplying a portion of the carbon black 
containing effluent into the combustion chamber and controlling the amount 
of this portion by varying the parameters of air supplied into said 
injection means. 
It is preferable that the injection means have a receiving chamber for the 
carbon black containing effluent communicating with a mixing chamber for 
intermixing the carbon black containing effluent with air, both being 
located within the apparatus housing, and a nozzle for air supply into 
said mixing chamber mounted inside the receiving chamber along the 
longitudinal axis of said mixing chamber. 
This arrangement of the injection means ensures an efficient utilization of 
air supplied into the injection means for the purpose of delivering said 
portion of the carbon block containing effluent into the combustion 
chamber. 
It is preferable that in the apparatus housing having a refractory lining, 
in accordance with the present invention said pipe for collecting a 
portion of the carbon black containing effluent and introducing it into 
the combustion chamber, as well as the receiving chamber and mixing 
chamber of the injection means be arranged in the refractory lining of the 
apparatus housing. 
This ensures reduced heat losses of the portion of the carbon black 
containing effluent delivered to the combustion chamber and an efficient 
utilization of the physical heat of said products in the process. 
As a result, the amount of the portion of the carbon black containing 
effluent supplied into the combustion chamber is reduced and the total 
yield of carbon black is increased. Furthermore, the metal deterioration 
of the reactor is lowered. 
The use of the process and apparatus for producing carbon black according 
to the present invention makes it possible to increase the total yield of 
carbon black when producing carbon black with different degrees of 
dispersity. Besides, the use of the process and apparatus according to the 
present invention ensures the production of carbon black with a high 
degree of structure.

In practicing the process for producing carbon black in accordance with the 
present invention, a fuel is combusted with air to form a stream of 
products of complete combustion of the fuel. 
Into this high-temperature stream of products of complete combustion of the 
fuel a hydrocarbon feedstock is fed which is decomposed by absorbing heat 
from the combustion gases with the formation of a carbon black containing 
effluent. 
A portion of said carbon black containing effluent in an amount of from 
about 2 to about 26% by volume is collected and fed into the combustion 
chamber as a fuel by way of injection with air under a pressure of from 
about 5 to about 10 atm.abs. Said combustion of a portion of the carbon 
black containing effluent as a fuel results in an increased degree of 
structure of carbon black and higher total yield of carbon black. 
Thereafter, the remaining portion of the carbon black containing effluent 
is quenched by introducing a cooling agent thereinto. In the present case, 
water is used as the cooling agent. 
Afterwards, carbon black is recovered from the remaining portion of the 
carbon black containing effluent by any conventional method suitable for 
this purpose which does not constitute the subject matter of the present 
invention. 
The process for producing carbon black according to the present invention 
will be now more fully apparent from the following detailed description of 
an apparatus intended for carrying out said process, and the operation of 
said apparatus. 
An apparatus for carrying out the process for producing carbon black 
according to the present invention has a housing 1 (FIG. 1) of a 
cylindrical shape provided with a refractory lining 1a. In the housing 1 
there are successively and coaxially mounted a cylindrical combustion 
chamber 2 communicating with a reaction chamber 3. The reaction chamber 3 
has a diameter smaller than the diameter of the combustion chamber 2. 
The apparatus is also provided with means for supplying fuel and air into 
the combustion chamber 2 which comprise four pipes 4 for air and four 
burners 5 for fuel mounted along the longitudinal axis of pipes 4 so that 
their axes are in parallel to the longitudinal axis of the housing 1. 
Pipes 4 and burners 5 are secured in a cover 1b of the housing 1 and 
located symmetrically relative to the longitudinal axis of the housing 1. 
In the reaction chamber 3 there is a nozzle 6 for the supply of cooling 
water which is radially mounted at one end of the reaction chamber 3 and 
fixed to the housing 1. The outlet tip 6a of the nozzle 6 is mounted along 
the longitudinal axis of the housing 1 and directed down-stream relative 
to the carbon black containing effluent. 
In the reactor there is a feedstock supply nozzle 7 mounted along the 
longitudinal axis of the housing 1 and fixed in the cover 1b of the 
housing 1. 
The reactor has three pipes 8 for collecting a portion of the carbon black 
containing effluent located symmetrically relative to the longitudinal 
axis of the housing 1. One end 8a of each pipe 8 is positioned radially 
relative to the reaction chamber 3 and connected with the latter prior to 
the nozzle 6. 
In accordance with the present invention, the other end of each pipe 8 is 
connected with the combustion chamber 2. 
In the vicinity of the other end 8b of every pipe 8 there are provided 
three injection means 9 (FIG. 2). The injection means 9 have a receiving 
chamber 10, a mixing chamber 11 and a nozzle 12 for supplying air, said 
receiving chamber, mixing chamber and the nozzle being mounted coaxially. 
The receiving chamber 10 communicates with the mixing chamber 11 and with 
the combustion chamber 2. 
The pipe 8 is positioned radially relative to the receiving chamber 10 and 
communicates therewith. 
The air supply nozzle 12, the outlet tip 13 which is arranged in the form 
of a Laval's nozzle is mounted inside the receiving chamber 10 and fixed 
in a pipe 14 of the housing 1. The injection means 9 are located so that 
their longitudinal axes are tangential with respect to the combustion 
chamber 2 generatrix. 
The pipes 8, as well as receiving chambers 10 and mixing chambers 11 of 
said injection means 9, are located in the refractory lining 1a of the 
reactor housing 1. 
Operation of the apparatus according to the present invention is as 
follows. 
Into the nozzles 12 of every injection means 9 compressed air is fed along 
the arrow A (FIG. 2) under a pressure ranging from 5 to 10 atm.abs. The 
air stream from the outlet tip 13 of the nozzle 12 is passed into the 
mixing chamber 11 and creates a rarefaction in the receiving chamber 10 of 
the injection means 9. As a result, the carbon black containing effluent 
is fed to the receiving chamber 10 through the pipe 8 from the reaction 
chamber 3 and mixed in the chamber 11 with the air stream. 
The resulting mixture of air with the carbon black containing effluent is 
further delivered to the combustion chamber 2 and the combustible 
components of the carbon black containing effluent is burned with the 
formation of a stream of products of the complete combustion of the fuel. 
To ensure complete burning of the combustible components of the carbon 
black containing effluent, air is fed into the combustion chamber 2 
through the pipes 4 in the direction of the arrow B (FIG. 1). 
Into the stream of the products of complete combustion of the fuel passed 
into the reaction chamber 3 an atomized hydrocarbon feedstock is fed along 
the arrow C through the feedstock nozzle 7. To ensure a better atomization 
of the feedstock, compressed air is also fed into the nozzle 7 along the 
arrow D. As the feedstock use can be made of oil or coal refining 
products. 
In the reaction chamber 3 the hydrocarbon feedstock is decomposed by 
absorbing heat from the products of complete combustion of the fuel, with 
the formation of a carbon black containing effluent. A portion of the 
carbon black containing effluent in an amount ranging from about 2 to 
about 26% by volume is fed to combustion as a fuel. The remaining portion 
of the carbon black containing effluent is quenched by introducing 
atomized water thereinto through the nozzle 6 along the arrow E. 
The cooled carbon black containing effluent is withdrawn from the reactor 
and carbon black is recovered from the remaining portion of the carbon 
black containing effluent by any conventional method suitable for this 
purpose. 
During the period of warming-up the reactor and bringing it under 
conditions of carbon black formation, a hydrocarbon fuel (propane-butane 
mixture) is fed into the combustion chamber through burners 5 along the 
arrow F. After supply of the feedstock into the reactor and formation of 
the carbon black containing effluent, the hydrocarbon fuel supply is 
minimized or completely stopped. 
EXAMPLE 1 
Air under pressure of 5.5 atm.abs. is fed into the nozzles 12 of the 
injection means 9. The total amount of air supplied into three nozzles 12 
is 105 nm.sup.3 /hr, i.e. 105 m.sup.3 /hr under normal conditions. As a 
result of air injection, a portion of the carbon black containing effluent 
in the amount of 2.03% by volume is passed into the receiving chambers 10 
from the reaction chamber 3 through the pipes 8. The collected portion of 
the carbon black containing effluent is mixed with air in the mixing 
chamber 11 and then passed into the combustion chamber 2. Air for burning 
in the amount of 1,750 nm.sup.3 /hr at a temperature of 250.degree. C. is 
fed into the chamber 2 through the pipes 4. 
As a result of combustion of combustible components of the collected 
portion of the carbon black containing effluent with air, a stream of 
products of complete combustion of the fuel is formed. Into said stream of 
products of complete combustion of the fuel fed into the reaction chamber 
3 an atomized hydrocarbon feedstock preheated to temperature of 
180.degree. C. is admitted in the amount of 500 kg/hr. 
To ensure atomization of the feedstock, air is fed into the nozzle 7 under 
pressure of 8 atm.abs. in the amount of 300 nm.sup.3 /hr. 
The feedstock employed is a commercial hydrocarbon feedstock with 
correlation index of 120. 
In the reaction chamber 3 the hydrocarbon feedstock is decomposed at 
temperature of 1,550.degree. C. with the formation of the carbon black 
containing effluent. A portion of said carbon black containing effluent in 
the amount of 2.03% by volume, or 0.1 Nm.sup.3 per 1 kg of the feedstock, 
is delivered into combustion chamber as a fuel. 
The remaining portion of the carbon black containing effluent is quenched 
to temperature of 650.degree. C. by way of introducing, through the nozzle 
6, atomized water under pressure of 15 atm.abs. thereinto. 
The cooled carbon black containing effluent is withdrawn from the reactor 
and then carbon black is recovered from the remaining portion of the 
carbon black containing effluent. 
The total yield of carbon black is 42.2% by weight. The resulting carbon 
black has the specific surface area of 72.4 m.sup.2 /g and 
dibutylphthalate absorption of 138 ml/100 g. 
The term "dibutylphthalate absorption" characterizes the degree of 
aggregation of carbon black particles (degree of structure) and 
corresponds to a minimum amount of dibutylphthalate necessary for complete 
wetting of carbon black particles (when the total weighed mass of carbon 
black can be collected on a glass spattle). Absorption of dibutylphthalate 
is determined in the following manner: about 0.5 g of carbon black weighed 
with the accuracy of up to 0.01 g is placed into a porcelain cup and 
dibutylphthalate is dropwise added thereto from a microburette. After each 
drop the mixture of carbon black and dibutylphthalate is thoroughly rubbed 
with a spattle till all traces of dibutylphthalate are removed from the 
cup walls. The addition of dibutylphthalate is stopped at the moment when 
all carbon black is collected on the spattle and a tablet thus prepared is 
not broken after being subjected to light compression. 
Dibutylphthalate absorption (X) expressed in ml/100 g is calculated from 
the formula: X=200x V, wherein V is a volume of absorbed dibutylphthalate, 
in ml. 
The term correlation index relates to the content of aromatic compounds in 
the hydrocarbon feedstock. More specifically, it expresses the 
relationship between the feedstock density and boiling point according to 
the formula: 
EQU CI=473.7 d-456.8+(48640/T) 
wherein 
CI is correlation index; 
d-feedstock density at 16.degree. C., g/cm.sup.3 ; 
T-average molecular boiling point, .degree.K. 
EXAMPLE 2 
Into the nozzles 12 of the injection means 9 air is fed under a pressure of 
7 atm.abs. The total air amount supplied into three nozzles 12 is equal to 
270 nm.sup.3 /hr. As a result of air injection, a portion of the carbon 
black containing effluent in the amount of 4.34% by volume is fed into the 
receiving chambers 10 from the reaction chamber 3 through the pipes 8. The 
collected portion of the carbon black containing effluent is mixed with 
air in the mixing chamber 11 and then passed into the combustion chamber 
2. Into the combustion chamber 2 air for burning is supplied in the amount 
of 1,000 nm.sup.3 /hr at a temperature of 250.degree. C. through the pipes 
4. Combustion of combustible components of the collected portion of the 
carbon black containing effluent results in the formation of a stream of 
products of complete combustion of the fuel. Feedstock supply into the 
stream of products of complete combustion of the fuel and decomposition 
thereof are performed under conditions similar to those described in the 
foregoing Example 1. A portion of the resulting carbon black containing 
effluent in the amount of 4.34% by volume, or 0.154 nm.sup.3 per 1 kg of 
the feedstock, is further fed into combustion chamber as a fuel. 
The remaining portion of the carbon black containing effluent is quenched 
and carbon black is recovered therefrom following the procedure described 
in Example 1. 
The total yield of carbon black is 54.1% by weight. The resulting carbon 
black has a specific surface area of 75 m.sup.2 /g and dibutylphthalate 
absorption of 146 ml/100 g. 
EXAMPLE 3 
Into the nozzles 12 of the injection means 9 air is supplied under a 
pressure of 8.5 atm.abs. The total amount of air fed into the three 
nozzles 12 is 315 Nm.sup.3 /hr. As a result of air injection, a portion of 
carbon black containing effluent in the amount of 16% by volume is passed 
into the receiving chambers 10 from the reaction chamber 3 through the 
pipes 8. The collected portion of the carbon black containing effluent is 
mixed in the mixing chamber 11 with air and then fed into the combustion 
chamber 2. Through the pipes 4 air is fed into the combustion chamber for 
burning in the amount of 880 Nm.sup.3 /hr at a temperature of 250.degree. 
C. 
As a result burning of combustible components of the collected portion of 
the carbon black containing effluent a stream of products of complete 
combustion of the fuel is formed. The feedstock supply into the reactor 
decomposition thereof are carried out under conditions similar to those 
described in Example 1. 
A portion of the resulting carbon black containing effluent in the amount 
of 16% by volume, or 0.615 Nm.sup.3 per 1 kg of the feedstock, is fed into 
the combustion chamber as a fuel. 
The remaining portion of the carbon black containing effluent is quenched 
and carbon black is recovered therefrom following the procedure described 
in the foregoing Example 1. 
The total yield of carbon black is 58.4% by weight. The resulting carbon 
black has the specific surface area of 73.5 m.sup.2 /g and 
dibutylphthalate absorption of 148 ml/100 g. 
EXAMPLE 4 
Into the nozzles 12 of the injection means 9 air is fed under a pressure of 
9.5 atm.abs. The total amount of air supplied into three nozzles 12 is 500 
Nm.sup.3 /hr. As a result of air injection a portion of carbon black 
containing effluent in the amount of 25.5% by volume is passed into the 
receiving chambers 10 from the reaction chamber 3 through the pipes 8. 
The collected portion of the carbon black containing effluent is mixed in 
the mixing chamber 11 with air and passed into the combustion chamber 2. 
Air for burning in the amount of 660 Nm.sup.3 /hr at a temperature of 
250.degree. C. is fed into the combustion chamber 2 through the pipes 4. 
As a result of combustion of combustible components of the collected 
portion of the carbon black containing effluent with air, a stream of 
products of complete combustion of the fuel is formed. The feedstock 
supply into the reactor and decomposition thereof are performed following 
the procedure described in Example 1. 
A portion of the resulting carbon black containing effluent in an amount of 
25.5% by volume, or 1.0 Nm.sup.3 per 1 kg of the feedstock, is fed into 
the combustion chamber as a fuel. The remaining portion of the carbon 
black containing effluent is quenched and carbon black is recovered 
therefrom under conditions similar to those described in Example 1 
hereinbefore. 
The total yield of carbon black is 56.7% by weight. The resulting carbon 
black has a specific surface area of 71 m.sup.2 /g and absorption of 
dibutylphthalate of 150 ml/100 g. 
EXAMPLE 5 
This Example illustrates a prior art process for producing carbon black 
with the use of a hydrocarbon fuel. 
Air for burning in the amount of 2,280 Nm.sup.3 /hr at the temperature of 
250.degree. C. is passed through the pipes 4, while through the burners 5 
an hydrocarbon fuel is passed in the amount of 50 Nm.sup.3 /hr. 
As the hydrocarbon fuel use is made of a propane-butane mixture in a 
volumetric ratio of 1:1. As a result of combustion of the hydrocarbon fuel 
with air in the combustion chamber 2, a stream of products of complete 
combustion of the fuel is formed. 
The feedstock supply into the reactor and decomposition thereof, as well as 
quenching of the resulting carbon black containing effluent are carried 
out following the procedure described in Example 1. 
The total yield of carbon black is 39.4% by weight. The resulting carbon 
black has a specific surface area of 74 m.sup.2 /g and dibutylphthalate 
absorption of 126 ml/100 g. 
As follows from the above-given Examples, the process and apparatus for 
producing carbon black according to the present invention provides a 
considerable increase in the total yield of carbon black as calculated per 
the total mass of the employed hydrocarbon feedstock and fuel. The need in 
hydrocarbon fuel is substantially reduced. 
Furthermore, the process and apparatus for producing carbon black according 
to the present invention ensure a substantial increase of the degree of 
structure of carbon black (as determined by the value of dibutylphthalate 
absorption). 
It is to be understood that the persons skilled in the art can introduce 
various modifications into the process and apparatus for producing carbon 
black described hereinabove as a non-limiting Example, without, however, 
falling beyond the scope of the present invention.