The technological flow(anthraccite)：Pre-purifying gas produced by gasifier , whose temperature is 500~600℃, gets into double –standpipe to be cooled by hot circulating water and washed out part dust. Then the gas gets out from the bottom water seal of standpipe. The gas temperature is about 80~90℃ form the standpipe. Then the gas enters into washing tower for cooling and removing dust, the gas temperature is lowered to 35~45℃. Finally, the gas is pressured by gas pressure adder and removed water and tar by trap water, then the gas send to the user.