The utilization of combustible waste gas is an important way of energy conservation and emission reduction.The progress in utilization technologies of landfill gas

flare gas

associated gas and coalbed methane has been presented.Due to the very low utilization ratio and insufficient resourceful utilization of landfill gas

the waste landfill treatment of which the leachate treatment and efficient LFG extraction and utilization are the key technologies should be widely popularized.Generally

the flare gas is fired to provide heat which is then recycled by waste heat boiler.Sometimes it can be directly burned in gas turbine for power generation.With low yield

the associated gas can be used as the injection fluid for oil production

or for field power generation.When the yield is high and stable

the associated gas can be transported by pipelines

liquid natural gas(LNG)and compressed natural gas(CNG)ships.The optimal utilization of low concentration coalbed methane is for gas-steam combined cycle power generation

of which the power generation efficiency can reach up to higher than 45%.Usually

the coalbed methane is applied as assistant air in mine-mouth power plants

for the technical requirements and cost of this method are the lowest.