CS195774B1 - Method of producing carbon black - Google Patents

Description

(54) Carbon black production

The invention relates to a method for producing carbon black.

The invention can be effectively used to produce retort blacks of various structures added as fillers for polymer blends.

The structure is one of the most important properties of the carbon black, which is critical to the quality of the carbon black-filled polymer blends: the structure of the carbon black is the degree of growth of the carbon black particles in the chains. During the production process in the reactor, the individual carbon black particles are packaged into branched aggregates consisting of multiple particles.

The average number of particles in the aggregates of each type of carbon black is different. The higher the average number of particles in the aggregates, the higher the structure of these carbon blacks.

Various analytical passages are available to determine the carbon black structure. The structure of carbon black in this work was determined by the absorption of oil (dibutyl phthalate).

As the carbon black structure increases, the absorption value of dibutyl phthalate increases.

There is known a method for producing carbon black by pyrolytic decomposition of a hydrocarbon-based feedstock in hot combustion gases of a fuel, wherein a stream of oxygen-containing gas having an oxygen content of at least 33% by volume is introduced coaxially to the feedstock stream. The oxygen-containing gas is present in an amount sufficient to provide at least 0.057 Nm ^{3 of} oxygen per kg of feedstock to the reactor (U.S. Pat. No. 3,355,247, IN Patent 97,738). The structure of the carbon black increases with increasing consumption of oxygen-containing gas and increasing oxygen content in the gas. The method makes it possible to obtain carbon blacks of different structures when using a feedstock of a particular composition.

The disadvantage of the known process lies in the high oxygen consumption and the lower efficiency.

It is also known to produce a carbon black in which hot combustion gases of a fuel are fed in which a stream of a hydrocarbon-based feedstock mixture with an oxygen-containing gas (air) is fed and coaxially an air stream is mixed with the flue gases fuel, and then the hydrocarbon-based feedstock is pyrolyzed to soot (see VP Sujeva, VV Michailov, "Production of soot", Chemie Verlag, Moscow USSR, 1965, pp. 118-129). In this way, carbon black can be produced from the feedstock in high yield.

A disadvantage of the known method is that it does not give any possibility to increase the structure of the carbon black by adding raw materials of a certain composition, as well as to obtain carbon black with different levels of structure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a carbon black production method with feed characteristics of a hydrocarbon-based feedstock with an oxygen-containing gas and a coaxial air stream blown therethrough to obtain a carbon black with increased structure while reducing oxygen consumption.

SUMMARY OF THE INVENTION In a process for producing a carbon black in which hot combustion gases of a fuel are first obtained by combustion of a fuel with an oxidizing agent, a hydrocarbon-based stream with an oxygen-containing gas and an air stream coaxially therewith is introduced into the combustion gases of the fuel. both streams are mixed with the combustion gases of the fuel, and then the hydrocarbon-based feedstock is pyrolytically decomposed to carbon black, using a hydrocarbon-based feedstock mixture with an oxygen-containing gas and an air stream at a rate below 5.0, the air is given in an amount sufficient to provide about 0.003 to 0.02 Nm ^{3 of} oxygen or 0.1 to 1.0 Nm ^{3 of} air per kg of feedstock.

By the method of the invention, the carbon black structure can be increased, the carbon blacks can be obtained at different levels of structure and the oxygen consumption reduced.

Suitably, the stream of the hydrocarbon-based feedstock mixture with the oxygen-containing gas is present at a rate below 100 m / s and an air stream at a rate of 20 to 150 m / s.

At these rates, the carbon black with the highest structure can be obtained.

In order to carry out the process more efficiently, it is expedient to use an oxygen-containing gas with more than 20% oxygen content.

The invention will be explained in more detail below with reference to the accompanying drawing. The figure in the drawing shows a longitudinal section through one of the building structures of a reactor for carrying out the process of the invention.

The process according to the invention can also be implemented with another reactor design.

Next, one of the reactor building structures for carrying out the process of the invention is described.

The reactor comprises a body 1 lined with a heat insulating material 2 and a fire-resistant substance 3,

Inside the reactor, a duct 4, a combustion chamber 5 and a reaction chamber 6 with a narrowed downstream section 7 are arranged one after the other and coaxially.

Tangentially arranged channels 8 enter into the combustion chamber 5.

At the end of the downstream reaction chamber 6 are channels 9.

On the front cover 7 of the reactor, a feed device for the mixture of hydrocarbon-based feedstock with an oxygen-containing gas is installed in the channel 4 by means of a sleeve 11 with a neck 12 and a flange 13.

The feed device for the hydrocarbon-based feedstock mixture with the oxygen-containing gas consists of a tube 14 and a tube 15 with a neck 16. The tubes 14 and 15 form a circular channel 17. The end of the tube 15 is closed by a blind flange. At the end of the tube 14 is located a mixing device 18 which is partially introduced into the opening of the circular blind flange and closes the opening. The lining 3 and the tube 15 form an annular channel 19.

The carbon black production process in the above reactor is carried out as follows.

The fuel and the oxidizing agent, mostly air, are fed from respective sources (not shown) through tangentially arranged channels 8 under pressure to the combustion chamber 5. The oxidizing agent can be preheated in any suitable apparatus to a temperature of 200 to 400 ° C. The oxidizing agent is usually supplied in an amount greater than that required by the combustion of the fuel, using natural gas, petroleum gas, and liquid fuel as fuel.

In the combustion chamber 5, the oxidized agent fuel is combusted to produce hot combustion gases.

The hydrocarbon-based feedstock preheated to 200 to 320 ° C in any suitable apparatus (not shown) is supplied from a source (not shown) at an overpressure of from 0.5 to 0.7 MPa via line 14 of the mixing apparatus 18. of the same mixing device 18, an oxygen-containing gas (not shown) flows through the orifice 18 and the circular channel 17 at an overpressure of 0.5 to 0.7 MPa with a flow mass that can deliver from 0.003 to 0.02 Nm ³ oxygen per kg The hydrocarbon-based feedstock mixture with the oxygen-containing gas formed in the mixing device flows into the combustion chamber 5 at a velocity below 100 m / s. Coaxial to the stream of the hydrocarbon-based feedstock with oxygen-containing gas, a stream (not shown) air preheated in any suitable device to a temperature of 250 to 350 ° C under an overpressure of 0.5 to 0.7 MPa through the neck 12 and the circular channel 19 with a flow material that can be fed from 0.1 to 1.0 Nm ³ of air per 1 kg of raw material. The method assumes that the current is fed a mixture of hydrocarbon feedstocks to oxygen containing gas and the air stream velocity ratio below 5.0.

The stream of the hydrocarbon-based feedstock mixture with the oxygen-containing gas and the coaxial air stream surrounded by the combustion gases enter from the combustion chamber 5 through the narrowed section 7 into the reaction chamber 6 where the streams are mixed with the combustion products of the fuel.

The hydrocarbon-based feedstock is decomposed in the reaction chamber 6 to form carbon black.

At the end of the reaction chamber 6, the reaction products are cooled by means of coolant (water) through the channels 9. The cooled reaction products are withdrawn from the reactor.

The above-described method for producing carbon black is illustrated in more detail by way of specific exemplary embodiments.

Examples

Example 1

This series of experiments was carried out in the reactor and in the manner described in the introduction. Natural gas having a flow rate of 205 Nm ³ / h and air preheated to 300 ° C with a flow rate of 2600 Nm ³ / h was fed continuously to the combustion chamber 5 of the reactor. A mixture of the hydrocarbon-based feedstock with the oxygen-containing gas of the bullion is fed axially into the reactor. The raw material consumption was 600 kg / h. The properties of the carbon black are shown in Table 1.

T a b u 1 k a 1

Characteristic

Name value

Characteristic

Name value C 89.8 H 7.8 WITH 1.5 O + N 0.9 3. Coking according to Konradson,% 0.52

As the oxygen-containing gas,

Claims (2)

using air preheated to a temperature of 280 ° C, which was introduced coaxially with the stream of the hydrocarbon-based feedstock mixture with the oxygen-containing gas. Carbon black with a specific geometric surface area of almost 96 m ² / g was obtained. The results of the experiments are shown in Table 2 for comparison with the known process data. 1. Density, g / cm ³ 2. Elemental analysis,% 1,043 WHAT Tfl Characteristic values of the method Known Experiment numbers and properties of carbon black Method 12 3 in Mi co CM 19S774 what O CM m O CO rH WHAT Ml CM Me θ Mi O rH CO M ^ • CO CM CD τ — 1 CM τ — 1 WHAT CM O CO M CM CD CO cm O M * CO cm 10 co lf) CM CD rH