CO2 Removal from Biogas by Water Washing System

CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%–94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure (from 0.8 to 1.2 MPa) could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temperature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%–83.2% when CO2 content in the simulated gas was 25%–45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural gas for vehicle fuel.

Graphical abstractCO2 removal from biogas by a pilot water washing system was investigated at various parameters, including liquid/gas ratio, pressure, temperature and initial CO2 content. Water was used as the absorbent, which could be recycled in the process through the regeneration. At certain conditions, a large amount of CO2 (25%–45%) in biogas could be decreased to less than 3%, which meets the requirement of CO2 content in natural gas for vehicle fuel.Figure optionsDownload full-size imageDownload as PowerPoint slide