What is coal lock gas compressors
coal lock gas compressors is a key process gas gas booster compressor in coal gasification plant, which is mainly used for conveying and pressurizing intermittent low pressure gas (I.e. coal lock gas) generated by coal ignition interlock. The gas usually contains dust, water, a small amount of tar and combustible components such as Halys, CO, chalys, etc. Special requirements are put forward for the tightness, corrosion resistance and operation stability of the compressor.
Positioning in coal gasification process
in the fiexed bed or moving bed coal gasification process, the coal lock gas is generated in the coal feeding stage-when the coal enters gasifier through the coal lock from the atmospheric coal bunker, part of the gas in the furnace needs to be released to balance the pressure. This part of gas enters the compression link after dust removal and cooling, and then is sent to the gas utilization system or the fuel gas pipe network. The compressor is at the connecting position between coal lock gas purification and downstream utilization.
Working Principle of reciprocating compressor
mainstream coal lock gas compressors adopts reciprocating structure, relying on crank and connecting rod mechanism to drive piston reciprocating motion in the cylinder to realize gas suction, compression and discharge:
- aspiration process: When the piston goes down, the volume of the cylinder increases, intake valve is opened, and the coal lock gas enters the cylinder after filtering;
- compression process: the piston goes up, inlet and exhaust valves is closed, the gas is adiabatic/variable compression, and the pressure rises;
- exhaust process: When the cylinder pressure is higher than the outlet back pressure, the exhaust valve is opened, and the compressed gas is discharged into the subsequent pipe network;
- clearance expansion: After the piston reaches the upper dead center, the high-pressure gas remaining in the clearance volume expands to create conditions for the next suction.
Key points of process adaptation
according to the characteristics of strong gas-locking fluctuation and large fluctuation of solid content of coal, buffer tanks are often configured in practical applications to stabilize airflow fluctuation; Oil-free lubricatoin or forced oil injection design is adopted to ensure sealing reliability; valve Selection takes into account the blocking resistance and response speed; The cooling system needs to match intermittent load changes to prevent condensation and fluid accumulation.