Study on Cleaning Technology of Municipal Solid Waste Landfill Gas (LFG)

Landfill gas (LFG) generated in municipal solid waste (MSW) landfills, which mainly contains CH₄ and CO₂, contributes to greenhouse effect and environmental degradation on the one hand, and constitutes a useful energy on the other hand due to its rich composition of methane. With this in mind, this study explored a new cleaning technology of LFG for the convenience of its application. In this study, chemical cleaning process was selected to remove CO₂ and H₂S from LFG and polyamine solution used at normal pressure, to study the influence of operating parameters on removal of CO₂ and H₂S. It was found that CO₂ and H₂S can be removed effectively from LFG and recovery rate of methane exceeds 99% under the following conditions: gas-liquid ratio between 12 and 40 (v/v), temperature of absorption column between 40 and 80 centigrade Celsius, temperature of stripping column between 85 and 120 centigrade Celsius. After this cleaning process, content of methane in the cleaned LFG (CLFG) exceeds 96%, and that of CO₂ and H₂S is less than 3% and 1 mg/m³ respectively. In addition, heating value of the CLFG exceeds 38 MJ/m³. Consequently, quality of the CLFG meet requirements of natural gas for vehicles and domestic use, yielding considerable economic and environmental benefits.