Low Pressure Dry Pulverized Coal Gasification Process

Abstract

The invention discloses a low-pressure dry pulverized coal gasification process, which includes feeding pulverized coal into a gasification furnace for gasification to obtain synthesis gas, and the synthesis gas is quenched by water in the lower section of the gasification furnace and then sent to a washing tower for washing. It is discharged from the top of the washing tower and sent to the subsequent process. The mixture of pulverized coal and oxygen is sprayed into the gasifier through the vertical nozzles on the top of the gasifier and multiple lateral nozzles on the side wall of the upper section, and is instantly ignited to form The flames are converging, and pulverized coal is gasified at high temperature to generate synthesis gas; the synthesis gas enters the right-angle elbow in the washing tower through the air inlet, and fully mixes with the water mist sprayed from the blocked nozzle at the outlet of the right-angle elbow And cool down, the non-atomized water flows into the lower section of the scrubber along the drain pipe at the bottom of the right-angle elbow, and the washed syngas is discharged from the top of the scrubber. The invention has the advantages of simple process, high gasification efficiency, low equipment investment and operation cost, good safety and reliability, energy saving and consumption reduction, and is especially suitable for dry coal pulverized gasification technology of low-pressure airflow technique.

Description

technical field [0001] The invention relates to the field of coal gasification, in particular to a low-pressure dry pulverized coal gasification process. Background technique [0002] At present, the gasification technology that uses coal as raw material to produce fuel gas through gasification mainly adopts fixed bed gasification technology. Fixed-bed gasification technology will be phased out gradually due to its high energy consumption - the carbon conversion rate is about 93%, and the waste water discharge index does not meet the environmental protection requirements - the organic matter content in the waste water is as high as 2000mg / L. [0003] Among the more advanced second-generation gasification technologies, the most representative ones are the pressurized gasification technology of coal-water slurry of GE Company of the United States, the GSP gasification technology of Siemens Company of Germany, and the pressurization of SCGP dry coal powder of Shell Company of t...

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Problems solved by technology

[0004] However, for the low-pressure gasification dry coal gasification technology with a gasification pressure of only 0.3-2.5 MPag, there are the following problems: 1. After the pulverized coal is injected into the gasifier with the transport gas, due to the relatively high pressure in the gasifier Low, resulting in reduced carbon conversion and gasification intensity, resulting in reduced gas production

In order to increase the carbon conversion rate, it is necessary to increase the volume of the gasification chamber in the gasifier to increase the residence time of the pulverized coal, which leads to high production and maintenance costs of the gasifier, and increased preparation costs and difficulties; 2. In order to To fully scrub the syngas, it is necessary to fully mix the syngas and the scrubbing liquid. In the past, a Venturi device was usually installed outside the scrubber to mix the syngas and the scrubbing liquid. The syngas will cause severe abrasion and even In order to improve the safety of operation, a sleeve is usually added outside the Venturi, which makes installation and maintenance inconvenient; 3. Due to the decrease in system pressure, the temperature of the black water discharged from the chilling chamber and scrubber is only over 100 degrees, which means Part of the heat is difficult to recover by flash evaporation, resulting in heat loss and increased energy consumption, which is not conducive to energy saving and consumption reduction

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