SIMULATION OF CO2 AND H2S EXTRACTION PROCESSES FROM BIOGAS USING AMINE AND WATER ABSORPTION

Abstract

The research of technological circuits of biomethane from biogas production with the use of the most widespread amine and water absorption processes of carbon dioxide and hydrogen sulfide removal from biogas is carried out. With the use of software modeling for the amine process, an effective absorbent MDEAmod — an aqueous solution of methyldiethanolamine and monoethanolamine is proposed. This absorbent can be effectively applied to a wide range of biogas and for a range of pressure practically from atmospheric to 0.28 MPa. At the same time, the heat load of desorber reboiler is less in 1.5–4 times compared with the use of monoethanolamine solutions.Comparison of energy costs for the production of biomethane using amine and water technology shows that taking into account the greater yield of biomethane in the amine process by 8–15 % than in water absorption (loss of CH4 due to dissolution in H2O), and the use of this difference to heat the amine desorber reboiler these costs are comparative. In the case of the need to produce carbon dioxide as a commodity product, the amine process has an advantage, since the CO2 achieved in this process has a concentration of 98 % versus 80 % when using water absorption. The obtained results of simulation of СО2 and H2S removal process by amine and water absorption can be used in technologies of biogas refining and production of biomethane - an analogue of natural gas, as well as carbon dioxide as a commercial product. Bibl. 24, Fig. 6, Tab. 4.