Process and device for coal-to-synthesis gas

Abstract

The invention relates to a process for preparing synthetic gas from coal. The process comprises the following steps: when gasified crushed coal is guided outa raw gas device (3)throughthe middle part of a gasification chamber, extracting raw gas which is 5-60% in volume; dedusting by using a cyclone separator (20); guiding out the rest of raw gas from a raw gas channel (III) on a double-channel static coal distributor (2) and mixing the raw gas with the raw gas dedusted by the cyclone separator (20); removing part of dust and tar by using a cyclone separator (21); then, further dedusting by using a washing cooler (5); cooling to reduce the temperature and feeding into a waste heat boiler (8) to recover waste heat; and finally, cooling the raw gas, feeding raw gas (18) with condensate which is separated by using a gas-liquid separator (11) to a downstream step, and feeding the washed condensate to a coal-gas-water separating device (15). The process provided by the invention has the advantages of energysaving, low operating cost, few bringing out amount of coal dust and less tar-containing gas water.

Description

technical field [0001] The invention belongs to the field of coal-based clean gas, and in particular relates to a process and device for coal-based synthesis gas. Background technique [0002] Crushed coal pressurized gasifier is a fixed bed coal gasifier, due to the low requirements for raw coal, that is, except for strong caking coal, other coal types can be gasified, especially low-rank coal and high ash melting point low quality coal. The gasifier is widely used in the field of coal-to-synthetic ammonia, methanol, dimethyl ether, synthetic oil and coal gas. As the current coal gasification technology develops in the direction of large diameter and high pressure, the amount of coal processed per unit time is gradually increasing. As a coal inlet for pressurized gasification of crushed coal, the coal lock needs to be continuously pressurized and released. To meet the development needs of large-scale coal gasification, in addition, the high pressure increases the coal gas...

AI Technical Summary

Problems solved by technology

As the current coal gasification technology develops in the direction of large diameter and high pressure, the amount of coal processed per unit time is gradually increasing. As a coal inlet for pressurized gasification of crushed coal, the coal lock needs to be continuously pressurized and released. To meet the development needs of large-scale coal gasification, in addition, the high pressure increases the coal gasification capacity and the amount of gas produced, coupled with the poor thermal stability of low-rank coal, etc., a single gas outlet will inevitably bring out a large amount of coal dust, resulting in subsequent gas Washing cooling, waste heat recovery and other sections cause blockage or separation difficulties. At the same time, excessive water is used for washing in the washing process, resulting in an increase in the production of gas and water and a decrease in high-grade heat.

[0003] Chinese Patent No. 200580041975.8 discloses a fixed-bed coal gasifier with a single coal lock and a single gas outlet on the static distributor. This gasifier is a commonly used pressurized gasifier for crushed coal at present, and there are outstanding problems The problem of dust in the crude gas is serious, the by-product is more low-pressure steam, and the gas contains dust, tar and water.

[0004] Chinese patent: 201320037548.4 discloses the use of a single coal lock, no static distributor, and a single gas channel, which also has the above problems

The purpose of this patent is to reduce the gas enrichment area, reduce the gas flow rate, and reduce the amount of coal dust carried out. It has a certain effect, but the effect is limited

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