Biogas to biomethane upgrading by water absorption column at low pressure and temperature

Biogas is a mixture of methane and carbon dioxide produced by the anaerobic digestion of biodegradable materials. It is composed primarily of methane and carbon dioxide and may contain small amounts of impurities. The removal of CO2 allows obtaining methane suitable to be injected into the gas grid. In this work it was chosen to operate the biogas upgrading by water washing in an absorption column at low pressure (1 bar) and low temperature (below 288 K) to verify the possibility to perform a fi rst step of this separation without high pressure contitions. The bench scale plant used is a continuous glass absorption column (internal diameter = 43 mm, height = 1000 mm) fi lled with a structured packing (Sultzer DX). The results obtained (70% reduction of CO2 at 282.2 K and using a L/G molar ratio of 868) open the possibility to investigate further the use of this technology for the biogas upgrading, at least for the fi rst major part of the CO2 removal.