Using renewable energy sources is an important pathway to meet the global energy demand, and the upgraded biogas has been prioritized. High pressure water scrubbing (HPWS) has been widely used for biogas upgrading, while the effect of H2S has not been studied well. The work aimed to study how H2S affects HPWS and to investigate whether and when an independent predesulfurization process is required for H2S removal. In this work, the H2S content in the raw biogas and the requirement on the upgraded biogas were surveyed, and the performance of HPWS was evaluated with different amounts of H2S in the raw biogas. The simulation shows that when H2S in the raw biogas is more than 1000 ppm, HPWS without any adjustment cannot meet the requirement of H2S removal; the removal of CO2 and H2S can be achieved by enhancing the desorption, leading to a slight increase of specific total annual cost, while the option of using hot air combined with a heat exchanger is worse than that of adding more air when the H2S in the raw biogas is more than 1600 ppm.
Keywords Biogas upgrading, high pressure water scrubbing, H2S, Aspen Plus