Gasification process of water/gas mixed full-chilled dry powder fuel and device

Abstract

The invention relates to a process for gasifying water / gas mixed type full chilling dry powder fuel and a special chiller thereof. The process resolves problems of poor cooling effect caused by only using water to chill high-temperature crude synthetic gases, no high-temperature resistance of spray throwers and easy corrosion and block of nozzles and pipes existing in dry powder fuel gasification process. Flammable dry powders are used as raw materials and undergo pressurized gasification, chilling and dust removal and cleaning; crude synthetic gases at a temperature of between 180 and 260 DEG C, which are used for downstream operating processes, are obtained, and the cleaning ash water obtained enters an ash water treatment system; chilling steps are as follows: when gasified crude synthetic gases at a temperature of between 1400 and 1700 DEG C rise to the middle part or the upper part of a gasifier, crude synthetic gases are partially chilled by water / gas mixed fog liquids as the temperature drops to between 800 and 900 DEG C, and then are sent to a water bath type chiller by a pipe for soaking, dust removal and chilling; when the temperature drops to between 180 and 260 DEG C, the cure synthetic gases undergo next step for dust removal and cleaning. The process has the advantages of simple process, good temperature drop effect, abrasion resistance of the chilling device under the condition of high temperature, no ashes collection in nozzles and pipes and long-time effective operation, and can avoid safety accidents.

Description

technical field [0001] The invention relates to a dry powder fuel gasification process, in particular to a water / air mixed fully chilled dry powder fuel gasification process and a special device thereof. Background technique [0002] In recent years, with the soaring price of petroleum, gasification using dry powder fuels such as coal and petroleum coke as raw materials is the basis and key for industrial processes such as coal-based chemicals, liquid fuels, combined cycle power generation, polygeneration systems and hydrogen production systems technology. [0003] With the development of process technology, in the technology of producing synthesis gas with solid fuel as raw material, the common fixed-bed intermittent gasification technology at atmospheric pressure has low production intensity, large discharge of "three wastes", low utilization rate of raw materials and low energy consumption. Other atmospheric pressure gasification technologies, including K-T furnace gasif...

AI Technical Summary

Problems solved by technology

But the main deficiency that this technology exists is also relevant with coal-water slurry: 1, contain about 40% water in the coal-water slurry, make its calorific value reduce

2. There are strict restrictions on raw materials, such as coal with poor slurryability, high ash content, and high ash melting point; 3. The gasification efficiency is relatively low, and the carbon conversion rate is about 96%.

4. Specific oxygen consumption is the highest among all kinds of entrained bed gasification processes; 5. Hot furnace walls must be used, and the cost of each furnace of refractory bricks is relatively high, and the service life is less than 2 years

But still there is following shortcoming in this technology: 1, equipment cost is high

The main factor of high investment is the use of waste heat boiler with membrane wall, high temperature and high pressure ceramic filter and chilled circulating gas compressor; 2. For the technological process followed by carbon monoxide conversion, the steam content in the product gas produced by this technology is insufficient, Additional steam is required; 3. The power consumption required for pressurizing the syngas for quenching the furnace is relatively large, which is not conducive to cost saving

4. The structure of key gasification equipment is complex, and the long manufacturing cycle makes the project construction cycle long

The effect of using steam to chill the crude syngas is better, but the operating cost will be too high due to the large amount of steam used alone

Chinese patent application No. 200610043195.3 discloses a "dry pulverized coal pressurized gasification chilling device and chilling process", which is to chill and cool the upstream crude synthesis gas through the principle of spraying water to cool down. The scheme has The following technical problems have not yet been resolved: 1. The single-use water spray is too large to mix with the crude syngas evenly, and the cooling effect is poor, and the desired cooling purpose cannot be achieved; 2. Ordinary sprayers cannot withstand high temperatures. Directly placed in high-temperature, high-pressure, dust-laden working conditions, the nozzle head is easily clogged with slagging, which cannot guarantee the continuous operation of the nozzle for a long time, especially during the operation of the gasifier, the high-temperature dust-laden gas will erode and abrade the nozzle head Changes in the size of the nozzle orifice will cause dripping or water leakage, which will cause the water to directly impact the inner wall of the gasifier and contact the high-temperature slag, resulting in an excessive temperature gradient, which will affect the quenching tube and the membrane wall of the reaction chamber of the gasifier. have a destructive effect and cause a serious accident

Therefore, it is impossible to achieve safe and effective quenching and cooling of syngas by using a single water spray of an unmodified sprayer

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