SU704462A3 - Method of fuel gasifying - Google Patents

Description

The invention relates to methods for gasifying solid fuels and can be used in the gasification of granular coal during the processing of raw gas condensate.

A known method of gasifying a fuel, e.g. granular coal, by countercurrent contacting solid particles of coal with oxygen-containing gas enriched with steam, obtaining a crude gas with a temperature of 400-700 ° C, containing coal dust and tar, cooling it to 160-220 ° C to produce condensate containing solids and separation of condensate into heavy and light fractions 1. Gasification contains a large amount of solids in the crude gas, which significantly contaminates the resulting condensate. The grain size of the fuel in the gas is quite significant, which complicates the work of gasification plants due to the addition of pipelines and pumps.

In order to intensify and increase the efficiency of the process, a heavy fraction of condensate with a solids content

no more than 60 ° / o are crushed and divided into two streams, one of which is directed to the contacting and the other to the separation, while the temperature of the streams is maintained above 70 ° C.

The drawing shows the technological scheme of the gasification installation for the implementation of the proposed method.

A solid fuel in the form of grains, in particular coal, is directed to the reactor I for gasification under pressure.

Pipeline 3 supplies oxygen-containing gas to the reactor, and pipeline 4 supplies water vapor. The ash that remains during gasification is removed through pipeline 5. During gasification under pressure in the reactor, the fuel is kept in a fixed bed and moves in a countercurrent opposite to the incoming gasification means, oxygen and water vapor. The crude gasification gas is supplied at a temperature of from 400 to 700 ° C from reactor 1 through pipe 6 to the washing cooler 7. In the washing refrigerator 7, the crude gas is brought into direct contact with a mixture of water and condensate with a temperature from

160 to 220 ° C. The gas washed and saturated with steam is directed through pipeline 8 to the waste-heat boiler 9. A portion of condensate collected in the washing cooler 7 is also added to the waste-heat boiler along the pipeline 10. The gas cooled in the heat-recovery boiler leaves it through line 11. Collected in the sump (not shown) of the waste heat boiler, condensate is directed through conduit 12 back to the washing cooler 7. Fresh water is supplied via conduit 13. In some cases it is necessary to direct the gas at the saturation temperature 160-180 ° C for further purification, for example, for use in a combined process of a gas steam turbine (not shown in Fig.). In this case, it may not be necessary to install a boiler. The saturated gas is then sent from the wash cooler for further (possibly necessary) cleaning. The mixture of condensate containing solids removed from the gas in the washing cooler 7 is discharged into the pipeline 14 and through one or several stages 15 the pressure of the mixture is reduced to atmospheric. The reduced pressure mixture is directed to a separation device 16, in which the various components of the mixture are separated by gravity. In the lower part of the separating device 16, the main part of the solid components is assembled, first of all with heavy high-boiling resin. In this way, low-boiling tar and oil from coal tar containing little dust are enriched with hydrocarbons, and then sent through conduit 17 for further processing. In the upper part of the gravity separation device 16 there is a mixture containing ammonia water, light hydrocarbons and oil oils. A drain pipe 18 is provided for this tank. The gas with reduced pressure is discharged from the separation device to the pipeline 19.

With a high content of solid matter, the fraction contained in the separation device 16 of the mixture is directed from the lower end of the separation device through conduit 20 to the crushing plant 21. The solids in the highly viscous carrier medium are crushed there so that grains remain. - about the maximum size of 2 mm.

By crushing the solids, the mixture passing through the crushing unit 21 is homogenized at the same time. The solid-containing condensate is conveyed from the crushing plant 21 by means of a pump 22 partially through line 23 by means of a dosing pump 24 again for gasification using pressure and for this purpose

supplied through line 25 to the upper part of reactor 1. Excess condensate mixture is directed through line 26 back to separation device 16, where it enters the pipe 27 with valve 28 or through pipe 29 with valve 30. Thus, a part of the condensate mixture containing solids circulates . Under certain positive gasification conditions, it is possible to direct all of the material from separation device 16 through line 20 to reactor 1 under pressure, so there is no need for the mixture to be circulated to pipework 26.

Example 1. Gas generator with a capacity of 2000 m of wet crude gas at 1. internal cross section of the reactor operates with coal.m, the characteristics of which are given. The content of resin (Fisher analysis), weight. % 12.5 Sintering to Dammu 12 Grain Width Coal (Grain Size Limits, mm) 3 to 30 Sweeling Index 4 The crude gas is removed from a gasification reactor operating at a working pressure of 20 bar at a temperature of 550 ° C and then cooled to flush cooler up to 180 ° C. A mixture of condensate containing cmola and dust is directed,; 1 to the gravitational separation device i6. From this separation device, a solid containing a solids fraction is withdrawn at either end, with an average grain diameter of solids equal to 1.5% mm. The content of solid BCHiccTB in the mixture is 20 wt.%.

Conventional pumps used to return the mixture to the reactor 1, as well as to circulate through conduit 26, fail after 10 hours of operation, as a result of which the gasification process is interrupted. Installing filters in line 20 prolongs the time required for gas production, however, it will be necessary for each reactor to remove pressure from the unit for 1 hour and destroy 100 liters of the mixture of resin and solids.

Example 2. The same gas generator is used as in Example 1, with (Jctr 2.5 times greater (5000 m of inaccurate gas per 1 m of internal cross section of the reactor). Coal, as well as the main production conditions are the same as in the example i. Due to an increase in productivity, the average diameter of the grains contained in the raw gas of solid substances increases by 5 mm. With the help of the pr (l; essa using the crushing plant 21), the solids in the mixture of the pipeline 20 are reduced to such an extent that they basically have a grain size less than 2 mm. The average grain diameter is 0.5 mm. 45% by weight of condensate mixture. Despite the fact that the condensate containing solid particles is not removed from the installation, gasification can be carried out continuously for many months.

Claims (1)

Invention Formula The method of gasifying a fuel, for example granular coal, by countercurrent contacting of solid coal particles with oxygen-containing gas enriched with steam, obtaining a crude gas with a temperature of 400-700 ° C containing coal dust and tar, cooling it to 160-220 ° C to produce condensate, containing solids, and separating the condensate into a heavy and light fraction, characterized in that, in order to intensify and increase the efficiency of the process, the heavy fraction of condensate with a solids content of not more than 60% is ground and is divided into two streams, one of which is directed to contacting and the other to separation, with the temperature of the streams being maintained above 70 ° C. Sources of information taken into account during the examination 1. Patent of Germany No. 2352900, cl. From 10 J 3/32. 04/03/75 (prototype).