RU2190661C2 - Method for reprocessing coal into synthesis gas - Google Patents

Abstract

FIELD: chemical industry, heat engineering, metallurgy. SUBSTANCE: method involves preparing coal by producing colloid disperse fuel system with average surface size of disperse phase particles not in the excess of 1 micron; gasifying obtained fuel system in single stage in reactor having vertical tubes, into which said fuel system is supplied. Heat-carrier temperature in intertubular space of reactor is maintained within the range of 400-1,000 C and temperature in tubes within the range of 200-800 C. Method is used for production of synthesis gas as primary raw material for obtaining chemical products, such as light hydrocarbons, for production of city gas, as well as for metal smelting. Synthesis gas is produced without use of outer oxidizers at moderate temperature conditions. EFFECT: increased efficiency and simplified process. 1 dwg

Description

The invention relates to the thermal processing of coal into synthesis gas and can be used in the chemical industry in the production of synthesis gas as a primary raw material for the production of chemical products, for example light hydrocarbons (CH ₄ , etc.), in the energy sector for the production of urban energy gas, metallurgy in metal smelting, etc.

A known method of thermal processing of solid fuel to produce synthesis gas, comprising pre-mixing the crushed coal with a gaseous oxidizing agent and its subsequent gasification by feeding into the electric arc zone so that the velocity vector of this mixture has a component parallel to the arc axis. In this case, the average temperature of the synthesis gas is maintained at a level of 1200-1700 ^o With the regulation of the power of the electric arc. As an oxidizing agent in this method, water vapor and oxygen are used in the ratio: water vapor 15-45%, and oxygen 55-85% // 1 / French Patent 2491490, M. cl. C 10 J 3/46 /.

 The use of oxygen as an oxidizing agent leads to the ballasting of synthesis gas with carbon dioxide, in addition, a special installation is required to produce oxygen. All this leads to additional energy costs, since the synthesis gas must be cleaned, and the oxygen obtained must be accumulated and stored, in all probability, in a liquid state. In addition, maintaining the temperature of the resulting synthesis gas by controlling the power of the electric arc is inefficient, unreliable and difficult.

 There is also known a plasma-metric method for processing coal into synthesis gas, including the preparation, heat treatment and gasification of coal using plasma in a plasma reactor, while the gasification process is carried out in three stages, two of which are carried out in tubular heat exchangers of the gasification column, and the third, final, gasification stage is carried out directly in the plasma reactor volume simultaneously with the process of high temperature pyrolysis in the presence of a reagent. Coal preparation is carried out by dispersing it in methanol water, to which surfactants, alkyl amides, are added, and the resulting coal suspension is heated in horizontal pipes before the first gasification stage to 500-600K in the stream of flue gases leaving the gasification column supplied to the reactor annulus and before the second stage of gasification, the coal suspension is heated to 1200-1400K in a stream of synthesis gas discharged from the plasma reactor. As a reagent for high-temperature pyrolysis, water vapor is used that is injected into the reaction zone using plasma sources so that the velocity vector of the plasma jets and the velocity vector of the gasified mixture are opposite to each other when projected onto the axis of the plasma reactor and coincided when they are projected onto the plane, perpendicular to the axis of the plasma reactor. The synthesis gas obtained in the plasma reactor is cooled and purified from impurities in a centrifugal bubbler using atmospheric air and water, while the atmospheric air is then used with a part of the synthesis gas in the combustion device, and water is fed into a dispersing device for preparing a coal suspension // 2 / RF Patent 2047650, cl. 6 C 10 J 3/18, 1993 (prototype).

 The disadvantage of this method is the complexity of the technological process, carried out in three stages, as well as the difficult passage of the first suspension, and then coal and gaseous reaction products through the horizontal tubes of the reactor, which can lead to blockage of the pipes and their rupture.

In addition, in the known method, it is proposed that the final stage of synthesis gas production be carried out at very high temperatures of 2500-3000K (2227-2727 ^o C), which requires the use of non-traditional devices and materials for their manufacture.

 The purpose of the invention is the production of unballasted synthesis gas without the use of external oxidizing agents, at moderate temperatures and simplifying the technology for its production.

This goal is achieved by the fact that in the method of processing coal into synthesis gas, including the preparation and gasification of coal in a reactor, the preparation of coal is carried out by preparing a colloidal dispersed fuel system ECOWUT with an average surface particle size of the dispersed phase δ _s = [Σ (n $\genfrac{}{}{0ex}{}{\text{*}}{\text{i}}$ δ $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ ) / Σn _i ] ^0.5 , where n _i is the number of particles with a size of δ _i , not more than 1 μm, the gasification of the resulting fuel system is carried out in one stage in a reactor with vertically arranged pipes to which the specified fuel system is supplied, while the coolant temperature in the annulus of the reactor support in the range of 400-1000 ^o C, and the temperature in the pipes in the range of 200-800 ^o C.

A distinctive feature of the proposed method, namely the preparation of coal, carried out by preparing a colloidal dispersed fuel system EKOVUT with an average surface particle size of the dispersed phase of not more than 1 μm, will provide unballasted synthesis gas without the use of external oxidizing agents, at moderate temperatures and simplifying the technology for its production, since in the process of obtaining ECOWUT due to the mechanochemical destruction of the source coal, its mineral components and associated water molecules All components of both the solid phase and the dispersion medium are activated, and optimal conditions are created for the chemical interaction of the components of ECOWUT. As a result, all chemical reactions take place between the organic components and the oxidizing agent (water and water vapor) at lower temperatures. So, in the case of ECOWUT, the intense C + H ₂ O reaction begins at temperatures of 200-300 ^o C.

As a result of the reaction of the ECOVUT organic phase with water of the C + H ₂ О⇔СО + Н _{2 type} , a mixture of СО and Н ₂ , i.e. synthesis gas, is formed at temperatures of 200-800 ^o С and the production technology is simplified.

 To achieve the same goal, the production of synthesis gas is aimed at one stage in a reactor with vertically arranged pipes, into which an ECOWUT colloidal dispersed fuel system is fed, eliminating the possibility of pipe clogging and rupture.

Maintaining the temperature of the coolant in the annulus of the reactor in the range of 400-1000 ^o C, and the temperature in the pipes in the range of 200-800 ^o C, which does not require the use of non-traditional apparatuses and materials for their manufacture, leads to the same goal.

 The drawing schematically shows the installation with which the specified method of processing coal into synthesis gas.

 The installation comprises a hopper 1 for crushed coal, a tank 2 for water, an interactive mechanochemical reactor 3, a pump 4 for feeding ECOWUT, a reactor 5 with vertically arranged pipes 6, having a ratio of external diameter to height 1: 5-1: 30, a separator 7 for separation gaseous products and mineral wastes, a pipe cooler 8 for the synthesis gas and a separator 9, for example snail, for separating condensed water.

 A smoke exhauster (not shown) is used to supply the coolant to the annulus of the reactor 5 with the subsequent removal of exhaust gases for heat recovery and to the atmosphere. To supply cold air to the pipe cooler 8 for synthesis gas with subsequent removal of hot air for heat recovery is a blower fan (not shown).

 The invention is as follows.

 Crushed coal from hopper 1 and water from reservoir 2 are metered into an interactive mechanochemical reactor 3, in which an ECOWUT colloidal dispersed fuel system (environmentally friendly water-coal fuel) is prepared with an average surface particle size of the dispersed phase of not more than 1 μm.

 Prepared by ECOWUT pump 4 under a pressure of 2.0-10.0 MPa, depending on the composition of the source coal and the requirements for the final product, it is fed into vertically arranged pipes 6 of reactor 5.

In pipes 6 of reactor 5, a synthesis mixture of synthesis gas (CO and H ₂ ), a pair of unreacted water (H ₂ O), and ECOWUT solid mineral components are formed.

The resulting synthesis gas from the separator 7 for the separation of gaseous products and mineral waste is sent to a pipe cooler 8 for synthesis gas, where it is cooled with air to a temperature of 30-50 ^o C.

 Next, the synthesis gas is sent to a separator 9, where condensed water is separated from it, and then to the consumer.

 The condensed water separated in the separator 9 is removed from the process.

The coolant with a temperature of 400-1000 ^o With a smoke exhauster is sent to the annulus of the reactor 5 with vertically arranged pipes 6 to provide the necessary thermal conditions of the process - maintaining the temperature in the pipes 6 in the range of 200-800 ^o C.

 Mineral components ECOWUT from the separator 7 for the separation of gaseous products and mineral waste are removed from the process.

 The proposed method of processing coal into synthesis gas was implemented at the testing site of the NPP Gidrotruboprovod in Ramenskoye, Moscow Region.

 In accordance with the claimed method, the production of synthesis gas from fossil fuels of grade D of the Kuznetsk basin was made.

The resulting synthesis gas contains ballast components (CO ₂ 2-3%) and harmful impurities (H ₂ S 1-2%), has a high calorific value.

 Currently, work is underway to create a head unit for processing coal into synthesis gas by the claimed method.

Claims (1)

A method of processing coal into synthesis gas, including the preparation and gasification of coal in a reactor, characterized in that the preparation of coal is carried out by preparing a colloidal dispersed fuel system with an average surface particle size of the dispersed phase of not more than 1 μm, gasification of the resulting fuel system is carried out in one stage in reactor with vertical tubes, in which fuel fed to said system, wherein the temperature of the coolant in the annulus of the reactor is maintained in the range of 400-1000 ^o C, temperature in pipes - in the range 200-800 ^o C.