可燃废气利用是实现我国节能减排的重要途径之一。介绍了目前填埋气、火炬气、伴生天然气和煤矿瓦斯几种可燃废气的利用技术和工业应用现状。其中:填埋气的利用率很低,资源化利用技术不足,需大力推广以渗滤液处理、高效LFG抽排及利用为核心的填埋垃圾处理工艺;火炬气通常引入燃油或燃气锅炉加以利用,也可以将火炬气燃烧后利用余热锅炉回收热量,或者作为中等热值的气体,直接引入燃气轮机燃烧发电;伴生天然气的产量不高时,可以将其回注驱油或就地发电,产量高且稳定时,可以采用管道输送、液化天然气(LNG)和压缩天然气(CNG)船舶运输;对于低浓度瓦斯,燃气-蒸汽联合循环发电是其最好的利用方式,其发电效率高达45%以上;通风瓦斯通常作为助燃空气用于坑口电站,该利用方式的技术要求和成本最低。
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.