RU203961U1 - Small-sized reactor for producing carbon black by controlled pyrolysis of hydrocarbon gas - Google Patents

Abstract

The utility model refers to the technological equipment used to obtain technical carbon (soot) by pyrolysis of gaseous hydrocarbons and is aimed at increasing the resource and efficiency of using the most loaded units of this equipment - high-temperature hydrocarbon pyrolysis reactors. The small-sized reactor is intended for use in the development of new technological processes, providing the production of technical carbon of promising grades from hydrocarbon gas (HCG), made by mechanical processing of a billet in the form of a pipe from a heat-resistant alloy, divided into 5 zones: I - mixing chamber, II - combustion chamber, III - pyrolysis chamber of HCG, IV - product quenching chamber pyrolysis, V - product cooling chamber. The reactor includes: housing 11, protective shell 15, outer housing of the combustion chamber 12, nozzle for gas supply 4 to protect and cool the combustion chamber wall, nozzle grate 14, packing in the form of a soft metal wire 9, tangentially located fittings 1 and 2 for connecting to the high-pressure gas mains and oxygen-nitrogen mixture, respectively, electrode 10 for igniting the combustible mixture in the combustion chamber, fittings 3 with nozzles for feeding HCG for pyrolysis, fittings 5 with nozzles for quenching gas supply and 6 for supplying cooling air, fittings 7 and 8 for connecting temperature and pressure sensors, respectively, fitting 13 for connecting to the sampler line. The technical result is an increase in the stability of the parameters of the hydrocarbon pyrolysis process and expanding the possibilities of its regulation in order to obtain carbon black with a given particle size distribution and the parameters of the structure of particles under the condition of a high resource and resistance of the reactor to changing operating modes. 1 ill.

Description

The utility model refers to the technological equipment used to obtain technical carbon (soot) by pyrolysis of gaseous hydrocarbons and is aimed at increasing the resource and efficiency of using the most loaded units of this equipment - high-temperature hydrocarbon pyrolysis reactors.

A plant is known from the prior art in which carbon black is obtained as a result of plasma-chemical and thermal action on a preheated hydrocarbon feedstock, mainly liquid. In this case, the process is carried out in a flow-through reactor with a graphite lining, in which an electric discharge is created between the graphite electrodes (patent RU 2349545, C9).

However, in this device, the products of destruction of electrodes and reactor lining participate in the formation of soot particles from hydrocarbon feedstock, which negatively affects the structure and properties of the resulting carbon black. In addition, in this reactor, the process of pyrolysis of hydrocarbon feedstock is poorly controlled. In connection with the above, the quality of the obtained carbon black is not stable over the process time, and its particles have a significant scatter in size and structure parameters, which limits the scope of the obtained products.

The closest to the proposed utility model is a reactor for the production of carbon black, the inner lining of the most stressed sections of which is made using zirconium refractories and corundum-chromium mass (patent RU 149827, С09С), which made it possible to increase the temperature of hot gases before feeding them into the feed stream to 1980-2150 ° С and increase the yield of carbon black by 2-3%.

However, this device, due to the presence of ceramic materials unstable to temperature changes, requires a gradual increase in temperature as it reaches the operating mode and has a limited resource in terms of the number of operating cycles (reactor starts and stops). This also explains the limited possibilities for regulating the technological process for obtaining various grades of carbon black during the working cycle, which is necessary to achieve the maximum possible economic effect of using equipment used for low-tonnage production of expensive grades of carbon black.

In general, based on the foregoing, none of the known types of reactors for the production of carbon black has the potential to be used in the development of new technological processes that ensure the production of carbon black of promising grades.

The problem to be solved by the claimed technical solution is to increase the stability of the parameters of the hydrocarbon pyrolysis process and expand the possibilities of its regulation in order to obtain carbon black with a given particle size distribution and particle structure parameters, provided that the reactor has a high resource and resistance to changing operating modes.

The technical result is achieved through the use of a small-sized reactor for producing carbon black by controlled pyrolysis of hydrocarbon gas containing a chamber for mixing a hydrocarbon gas and an oxygen-nitrogen mixture, a combustion chamber, a pyrolysis chamber of hydrocarbon gas located between the section passing through the axes of the hydrocarbon gas supply holes for pyrolysis , and a section passing through the axes of the holes of the first row of inert gas supply for quenching the pyrolysis products, the quenching chamber and the pyrolysis products cooling chamber, located between the section passing through the axes of the air supply holes for further cooling the products, and the outlet from the reactor, characterized in that a chamber for mixing a combustible gas and an oxidizer, a combustion chamber, a pyrolysis chamber of a hydrocarbon gas and a quenching and cooling chamber for pyrolysis products are made as a single reactor vessel from a solid billet in the form of a heat-resistant alloy pipe connected at the outlet to the regulator at the pressure in the reactor in the form of a valve, while outside to the reactor vessel in the area of combustion chambers, pyrolysis and quenching of pyrolysis products, a protective shell with a stainless steel compensator and fittings for supplying gases to the reactor is welded, an inert gas, the pressure of which reduces the mechanical load on the reactor vessel during its operation, the wall of the combustion chamber is made perforated or porous, to increase the homogeneity of the combustible mixture, hydrocarbon gas and oxygen-nitrogen mixture are fed into the mixing chamber through tangentially located nozzles, and to equalize the flow in front of the combustion chamber and preventing the ignition of the combustible mixture in the mixing chamber 1 / 3-1 / 2 part of its volume from the side of the entrance to the combustion chamber is filled with a gas-permeable packing in the form of a soft metal wire, and to control the pyrolysis process and the state of the reactor, it is equipped with pressure and temperature sensors of the medium inside the reactor a and its walls and a sampling device. In addition, in order to expand the range of values of the residence time of soot particles under the conditions of their growth and material graphitization, a quenching medium is introduced into the flow of pyrolysis products through several groups of holes located at different distances from the channels for introducing hydrocarbon gas into pyrolysis.

The reactor design is illustrated in Fig. 1.

The reactor made by machining a workpiece in the form of a pipe 11 from a heat-resistant alloy is divided into 5 zones:

I - mixing chamber, in which a combustible mixture of hydrocarbon gas (HCG) is prepared, supplied through a tangentially located choke 1, and air or a mixture of oxygen and nitrogen supplied through a tangentially located choke 2;

II - combustion chamber, in which combustion of a combustible mixture occurs, ignited when the reactor is started from an electric discharge spark arising between the protruding end of the electrode 10 and the bottom of the combustion chamber (nozzle grid 14);

III - pyrolysis chamber of HCG, located between the section passing through the axes of the holes (nozzles) 3 supplying HCG for pyrolysis, and the section passing through the axes of the holes (nozzles) 5 of the first row of inert gas supply for quenching the pyrolysis products;

IV - quenching chamber located between the section passing through the axes of the holes (nozzles) 5 of the first row for supplying the quenching medium (inert gas) for quenching the pyrolysis products, and the section passing through the axes of the air supply holes 6 for further cooling the products;

V - product cooling chamber located between the section passing through the axes of the air supply holes 6 for further cooling the products and the outlet from the reactor.

To reduce the mechanical load on the reactor vessel during its operation from the outside, a protective shell 15 with a stainless steel compensator is welded to the reactor vessel in the area of the combustion chambers, pyrolysis and quenching of pyrolysis products. The unloading of the reactor vessel is carried out due to the fact that an increased pressure is created in the cavity between the reactor vessel and the containment shell as a result of the supply of a gas inert with respect to the structural materials of the reactor, for example, nitrogen.

To organize the cooling of the wall of the reactor 11 in the area of the combustion chamber from the outside, the outer casing 12 is attached to it.

Cooling gas is fed into the space between the reactor wall and the outer casing 12 through hole 4.

To control the process taking place in the reactor and the state of the reactor material, temperature sensors of the products and the walls of the reactor are used, as well as pressure sensors connected through the fittings 7 and 8, respectively.

Small-sized reactor operates as follows.

Through tangentially located nozzles 1 and 2, hydrocarbon gases and an oxidizer, a mixture of oxygen and nitrogen (air), are fed into the mixing chamber in the required ratio, which, thanks to the tangential inlet, are intensively mixed, forming a homogeneous combustible mixture. To equalize the flow of the combustible mixture in front of the nozzle grid 14, as well as to prevent the ignition of the combustible mixture in the mixing chamber due to accidental flashes of flame through the nozzle grid nozzles, approximately 1 / 3-1 / 2 of the volume of the mixing chamber adjacent to the nozzle grid 14 is filled gas-permeable packing in the form of a soft metal wire 9.

When the reactor is started, the combustible mixture entering through the nozzles of the nozzle lattice 14 is ignited by a spark arising when a high voltage electric current is applied in the region adjacent to the end of the electrode 10 protruding into the combustion chamber. Combustion is completely completed already at 2/3 of the length of the combustion chamber, therefore, UHG supplied for pyrolysis through nozzles 3 enters the flow of hot combustion products and, at a flow rate of hydrocarbon gases that is more than an order of magnitude higher than the flow rate of combustion products, quickly mixes with them, simultaneously heating to the temperature at which pyrolysis of its molecules begins.

In zone III of the reactor, the formation and growth of soot particles take place, as well as the transformation of the structure of their material, which stops under conditions of a sharp decrease in temperature as a result of mixing the pyrolysis products (soot aerosol) with the quenching medium. Depending on the required characteristics of carbon black, the supply of the quenching medium can be carried out through any one of the belts of holes 5.

To reduce the temperature of the products leaving the reactor to values acceptable for the operation of the valve that regulates the pressure in the reactor and equipment in which the solid phase (particles of carbon black) is to be separated from the aerosol, after the quenching zone, cooling air is introduced into the product stream through openings 6. At the temperature of the products in the area of the air supply openings (150-250 ° C), no reactions leading to the oxidation of carbon of soot particles and a change in their structure can occur.

To control the results of the pyrolysis process in the reactor through the choke 13, product samples are periodically taken, which are sent for research.

Claims (2)

1. A small-sized reactor for producing carbon black by controlled pyrolysis of hydrocarbon gas, containing a chamber for mixing a hydrocarbon gas and an oxygen-nitrogen mixture, a combustion chamber, a pyrolysis chamber of a hydrocarbon gas located between the section passing through the axes of the hydrocarbon gas supply holes for pyrolysis, and the section, passing through the axes of the holes of the first row of inert gas supply for quenching the pyrolysis products, the quenching chamber and the pyrolysis products cooling chamber located between the section passing through the axes of the air supply holes for further cooling the products, and the outlet from the reactor, characterized in that the combustible gas mixing chamber and oxidizer, the combustion chamber, the pyrolysis chamber of the hydrocarbon gas and the chambers for quenching and cooling the pyrolysis products are made as a single reactor vessel from a solid billet in the form of a heat-resistant alloy pipe, connected at the outlet to a pressure regulator in the reactor in the form of a valve, while outside to In the area of the combustion chambers, pyrolysis and quenching of pyrolysis products, a protective shell with a stainless steel compensator and fittings for supplying gases to the reactor is welded to the reactor vessel, an inert gas is fed into the cavity between the reactor vessel and the protective shell, the pressure of which reduces the mechanical load on the reactor vessel when work, the wall of the combustion chamber is made perforated or porous, to increase the homogeneity of the combustible mixture, hydrocarbon gas and oxygen-nitrogen mixture are fed into the mixing chamber through tangentially located fittings, and to equalize the flow in front of the combustion chamber and prevent ignition of the combustible mixture in the mixing chamber 1 / 3- 1/2 of its volume from the side of the entrance to the combustion chamber is filled with a gas-permeable packing in the form of a soft metal wire; moreover, to control the pyrolysis process and the state of the reactor, it is equipped with pressure and temperature sensors of the medium inside the reactor and its walls and a sampling device. 2. The reactor according to claim 1, characterized in that in order to expand the range of values of the residence time of the soot particles in the conditions of their growth and graphitization of the material, the quenching medium is introduced into the flow of pyrolysis products through several groups of holes located at different distances from the channels for introducing hydrocarbon gas to pyrolysis ...

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