RU2780839C1 - Method for complex processing of rubber waste - Google Patents

Abstract

FIELD: waste treatment.

SUBSTANCE: invention relates to the field of rubber waste (RW) processing with an integrated approach of the pyrolysis process and can be used in the processing of industrial hydrocarbon solid waste for various purposes. The method for complex logical processing is carried out in a mine-type reactor by heating crushed rubber in the form of granules with a heating rate of 9-12.5°C/min to a temperature of 550-700°C with no air access and maintaining this temperature until the end of the release of volatile substances, a methane-hydrogen gas mixture with a content of these components up to 90-95% is formed, which can be divided into pure components by the membrane technology method and/or used in the future at modular hydrogen and methane filling stations, and also partially used as fuel to maintain the endothermic pyrolysis process. The methane-hydrogen mixture can be used, preferably, for the production of electricity in a gas turbine or gas piston installation. The process of heat supply is carried out using the allothermal method through the reactor wall. During pyrolysis, flue gas with a temperature of 900-950°C is used to heat the reactor when burning part of the methane-hydrogen mixture. In the condensed phase of heavy hydrocarbons of the C₅-C₁₂ pyrolysis process, valuable substances are present in a significant amount, for example, D-Limonene, o-Cymene, etc., which are isolated by distillation as high-margin products. The heavy fraction of hydrocarbons remaining after distillation with a boiling point above 200°C can be used to produce flue gases with a temperature of 1100-1200°C sent to the reactor heating jacket to maintain the temperature of the solid carbon residue activation process by carbon dioxide gasification at a temperature from 940 to 1000°C in order to obtain carbon sorbents for various purposes. During carbon dioxide gasification, carbon monoxide (II) is formed, which is sent for the production of carbamide or for catalytic steam conversion to produce hydrogen and carbon monoxide (IV). When the resulting gas mixture is cooled, CO₂ is converted to a liquid state and sent to the receiver, and hydrogen is used at modular automobile filling stations. Liquid carbon dioxide is sent to the recycle for carbon dioxide gasification.

EFFECT: improving the quality of the solid residue, reducing emission of pollutants.

1 cl, 1 dwg

Description

The invention relates to the field of processing rubber waste (RTO) with an integrated approach to the process of their pyrolysis with the release of a methane-hydrogen gas mixture during pyrolysis, distillation of the condensed part of heavy hydrocarbons C ₅ -C ₁₂ from the gas part to obtain valuable products, gasification of the solid residue in a carbon dioxide environment with its simultaneous activation with the production of carbon sorbents for various purposes and carbon monoxide (II) and can be used in the processing of industrial hydrocarbon solid wastes for various purposes.

Known "Method of thermal processing of worn tires" (RU 2139187 according to IPC class B29 B17 / 00, F23 G7 / 12, C08 J11 / 16, 11/20 https://www1.fips.ru/publication-web/classification/mpk ?view=detail&edition=2018&symbol=F23G dated 10/24/1997). The method includes loading tires into the reactor, pyrolysis of the material, followed by separation of the pyrolysis products and unloading of the solid residue, the pyrolysis is carried out at 550-800°C in a reducing gas medium at its ratio to the material of 0.20-0.45:1. To improve the quality of carbon black (soot) at the end of tire pyrolysis, superheated steam is supplied at 250-500°C in a ratio of 0.03-0.12:1 to the loaded material. Reducing gas is obtained by the method of incomplete combustion of hydrocarbons (α = 0.4 - 0.85). The following can be used as hydrocarbons: methane, refinery gases and gases from the pyrolysis reaction (recycle).

The disadvantages of the known method are the low quality of the solid residue of carbon black (soot), the use of liquid products C ₅ - C ₁₂ only as a liquid fuel, the multicomponent and uncontrolled composition of the reducing gas (gasifying agent) does not allow obtaining pyrolysis gas for direct use or processing, a decrease in economic indicators process, negative impact on the environment.

Closest to the claimed invention is the well-known "Method of thermal processing of used tires and rubber products" (RU 2339510 according to class IPC B29B 17/00 dated 10.04.2007), including tire pyrolysis in a reactor at a temperature of 200-500 ° C, separation pyrolysis products in the separation apparatus, in which the pyrolysis products - gaseous hydrocarbons from C ₁ to C ₄ from the separation apparatus are fed into the lower part of the reactor, and the flue gases leaving the reactor furnace are passed through a heat exchanger located inside the reactor to heat the recirculated gases and the processed material and at the same time served in the hopper to heat the crushed material in it. Gaseous or liquid hydrocarbons of pyrolysis are used as fuel for obtaining combustion products. The pressure of the recirculation gases supplied to the lower part of the reactor is periodically changed in time, and the pressure of the removal of pyrolysis products from the upper part of the reactor is maintained constant, which ensures a periodic change in the pore pressure at each point of the processed material during pyrolysis in the reactor.

The disadvantages of this invention are the low quality of carbon black (soot) due to the supply of recirculating gases C ₁ -C ₄ for pyrolysis from the bottom up in the annular space between the reactor wall and the internal heat exchanger, does not provide a completely uniform distribution over the horizontal sections of the reactor, and therefore, does not all particles of rubber crumb reach the full yield of volatile substances, the complication of the pyrolysis control process due to the use of a number of technical devices, the composition of liquid hydrocarbons from C ₅ to C ₁₂ that are not given in the patent, going for processing, does not allow evaluating the value of the products obtained to determine the economic efficiency of the known way.

The technical result of the claimed invention is to improve the quality of the solid residue for obtaining effective sorbents for various purposes by gasification (carbon dioxide activation), ensuring the formation of a methane-hydrogen gas mixture during pyrolysis, carbon monoxide (II) during gasification of the solid residue and obtaining substances D-Limonen and o- Cymene by distillation from the condensed part of the heavy hydrocarbons C ₅ -C ₁₂ pyrolysis products, reducing pollutant emissions, increasing the economic performance of the pyrolysis process.

The technical result is achieved by the fact that the proposed method uses a complex (logical) processing of RTO, including the pyrolysis of tires in a shaft-type reactor at a temperature of 550-700 ° C until the end of the release of volatiles, cooling of gaseous pyrolysis products, separation of these products in a gas-liquid separator into methane- hydrogen gas mixture and part of heavy hydrocarbons C ₅ -C ₁₂ , separated by distillation into valuable components D-Limonene and o-Cymene, subsequent carbon dioxide gasification of the solid residue to obtain sorbents for various purposes, the process of using carbon monoxide (II), formed during the gasification of solid remainder. The process includes a logical step that continuously follows the pyrolysis stage, during which volatile substances are released with the formation of valuable products in the composition of the condensed phase С ₅ -С ₁₂ and in the composition of the non-condensed phase - a methane-hydrogen gas mixture with a content of these components up to 90 95% close to equal ratio and partial use of it for combustion and thereby maintaining the temperature of the pyrolysis process, as well as use in a gas turbine or gas - piston plant to generate electrical energy, the stage of carbon dioxide gasification (activation) to obtain effective sorbents for various purposes and the simultaneous formation carbon monoxide (II) sent for catalytic steam reforming to produce hydrogen and carbon dioxide, which is recycled for carbon dioxide gasification.

The invention is illustrated by a drawing, which shows the principle of operation of the RTO processing, in which the process of pyrolysis, carbon dioxide gasification of the solid residue of pyrolysis to obtain sorbents for various purposes, distillation of the condensed part of C ₅ -C ₁₂ into valuable components D-Limonene and o-Cymene, separation of methane- hydrogen mixture into pure components using membrane technology, catalytic CO steam conversion to produce hydrogen and CO ₂ with its return to the recycle for gasification.

The installation contains: 1 - reactor (pyrolyzer - gasifier), 2 - heat exchanger, 3 - gas-liquid separator, 4 - membrane separator, 5 - distillation plant, 6 - steam catalytic converter, 7 - boiler for burning combustible gases and heating oil, 8 - turbo expander, 9 - receiver for collecting liquid carbon dioxide, 10 - cylinder of liquid carbon dioxide, A - partial return line of methane-hydrogen gas for combustion and maintaining the temperature of the pyrolysis process, B - heating oil supply line for burning and maintaining the temperature of the gasification process , B - line for partial return of combustible gas CO for combustion and maintaining the temperature of the pyrolysis process.

The method is carried out as follows.

и

. до 90-95%, близким к равному соотношению. После отделения в сепараторе (3) неконденсируемой газовой смеси посредством мембранной технологии (4) получают водород

и метан

при этом часть метано-водородной смеси направляют для сжигания в котел (7) по линии А для получения дымовых газов, участвующих в обогреве реактора (1) для поддержания эндотермического процесса. Из жидкой фазы углеводородов путем дистилляции (5) выделяют ценные продукты Д-Лимонен и о-Цимен. Оставшийся кубовый остаток с температурой кипения выше 200°С частично используют, направляя его по линии Б в котел (7), из которого дымовые газы направляют на поддержание заданной температуры процесса газификации в реакторе (1). The resulting granulate during PTO grinding is loaded into the reactor (1), where it is heated at a rate of 9-12.5°C/min to a predetermined temperature of 550-700°C without air access and maintained for a predetermined time (in terms of volatiles) at this temperature. The pyrolysis products are removed from the upper part of the reactor (1) and fed into the heat exchanger (2), in which, when cooled to 20 - 25 ° C, a condensed part of the composition C ₅ -C ₁₂ (liquid phase) and a non-condensable phase are formed from hydrocarbon pyrolysis gases, consisting of

and

. up to 90-95%, close to an equal ratio. After separating the non-condensable gas mixture in the separator (3) by means of membrane technology (4), hydrogen is obtained

and methane

at the same time, part of the methane-hydrogen mixture is sent for combustion to the boiler (7) via line A to obtain flue gases involved in heating the reactor (1) to maintain the endothermic process. Valuable products D-Limonene and o-Cymene are isolated from the liquid phase of hydrocarbons by distillation (5). The remaining distillation residue with a boiling point above 200°C is partially used by directing it along line B to the boiler (7), from which the flue gases are sent to maintain the set temperature of the gasification process in the reactor (1).

After the end of the stage of pyrolysis of the PTO granulate (cessation of the release of volatile components), the stage of activation of the solid residue follows to obtain carbon sorbents for various purposes in the gasification process. When burning in the boiler (7) gaseous products through line A and heavy hydrocarbons with a boiling point above 200°C through line B, the solid residue of the pyrolysis process is subjected to heating to a temperature of 940-1000°C with a discreteness of 20°C, depending on the purpose of the resulting sorbent and include the supply of carbon dioxide from a cylinder of carbon dioxide (10). In the process of carbon dioxide gasification according to the Boudouard reaction, carbon monoxide (II) is formed more than 80% vol. Part of the high-calorific CO gas is sent to the boiler (7) to produce high-temperature flue gases involved in the process of ensuring the temperature of the pyrolysis and gasification process, and the remaining part is subjected to catalytic steam reforming in the converter (6) to produce H ₂ and CO ₂ . When the gas mixture is cooled in the turbo expander (8), CO ₂ passes into a liquid state and is sent to the receiver (9) to collect carbon dioxide for inclusion in the recycle of the gasification stage.

The temperature of the activation process determines the concentration of polar, non-polar and other groups on the carbon sorbent, the specific surface area, volume and pore size, as well as the sorption activity for iodine and methylene blue. The obtained sorbents have an attractive cost for industrial partners and competitiveness. The diversification of various market-demanded sorbents determines the reason for the withdrawal of energy-consuming methods of pyrolysis and gasification into one of the cost-effective integrated approaches to the implementation of the proposed method.

When carrying out carbon dioxide gasification according to the Boudouard reaction, carbon monoxide (II) is formed, which is in demand in the chemical industry, for example, in the production of urea. In the proposed method, carbon monoxide (II) is directed to catalytic steam reforming to produce hydrogen and carbon monoxide (IV) according to a known reaction. When the resulting gas mixture is cooled in a turbo-expander, CO ₂ is converted into a liquid state and sent to the receiver, and hydrogen is used at modular car filling stations. Liquid carbon dioxide is recycled for carbon dioxide gasification. The proposed method of RTO processing helps to reduce the environmental impact of carbon dioxide (CO ₂ ).

Claims (1)

The method of thermal processing of industrial rubber waste (RTO), including the pyrolysis of tires in the reactor at a temperature of 200-500 ° C, the separation of pyrolysis products in the separation apparatus, in which the pyrolysis products - gaseous hydrocarbons C ₁ -C ₄ from the separation apparatus are fed into the lower part of the reactor, and the flue gases leaving the reactor furnace are passed through a heat exchanger located inside the reactor to heat the recirculated gases and the processed material, and at the same time they are fed into the bunker for heating the crushed material in it, characterized in that it is a complex logical one, including a continuously following pyrolysis stage, during which volatile substances are released with the formation of valuable products, including D-Limonene, o-Cymene, in the condensed part of heavy hydrocarbons C ₅ -C ₁₂ , released during their distillation, and methane-hydrogen in the composition of the non-condensed phase gas mixture 90-95%, and partial use of both, t as well as the remaining heavy fraction of hydrocarbons after distillation with a boiling point above 200 ° C for combustion and thereby maintaining the temperature of the pyrolysis and gasification process, as well as the use of a methane-hydrogen mixture, preferably in a gas turbine or gas piston plant for generating electrical energy, a carbon dioxide gasification stage at a temperature of 940 to 1000°C to obtain sorbents and the simultaneous formation of carbon monoxide (II), directed to catalytic steam reforming with the production of hydrogen and carbon dioxide, which is returned after its liquefaction upon cooling to the recycle for carbon dioxide gasification.

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