COMPARATIVE ANALYSIS OF THE EFFICIENCY OF WATER AND WATER-AMINE ABSORPTION PROCESSES FOR EXTRACTING CO2 FROM BIOGAS

Abstract

The production of biomethane from biogas energy costsfor the most widely used amine and water processes for extracting carbon dioxide from biogas were analyzed using computer simulation. Combined water-amine absorption method of biogas purification from CO2 wasincluded in the comparative analysis. For the CO2 content of the biogas from 32 to 42 %, the specific energy costs when using water absorption to extract carbon dioxide from biogas are, on average, in ~ 2.5 times lower than amine absorption, but the loss of CH4 by water absorption was 7.1–7.6 % due to its watersolubility with practically zero CH4 loss when using amine absorption and insignificant loss (0.17–2.8 %) using water-amine technology. Using preliminary water absorption of CO2 saved CH4 can compensate the power consumption of the biogas compressor or the heatcosts of saturated amine absorbent regenerating. This will allowto reduce energy consumption to almost equal to water absorptionone. The results of simulation of carbon dioxide extraction from biogas can be used to optimize technological absorption schemes for the production of biomethane — an analogueof natural gas. Bibl. 13, Fig. 5, Tab. 6.