Economic assessment of biogas purification systems for removal of both H2S and siloxane from biogas. (May 2021)

• Record Type: Journal Article
• Authors: Zhang, Yuyao; Kawasaki, Yu; Oshita, Kazuyuki; Takaoka, Masaki; Minami, Daisuke; Inoue, Go; Tanaka, Toshihiro
• Is Part Of: Renewable energy. Volume 168(2021)
• Page Start: 119
• Page End: 130
• Publication Date: 2021-05
• Subjects: Siloxane -- Hydrogen sulfide -- Biotrickling filter -- Iron-oxide-based adsorbent -- Activated carbon -- Economic assessment; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2020.12.058
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: Biogas is a promising renewable biofuel, but hydrogen sulfide (H2 S) and siloxanes are major obstacles in the conversion of bioenergy from biogas because they damage biogas-processing equipment. This study evaluated two biogas-purification systems for a simultaneous efficient removal of H2 S and decamethylcyclopentasiloxane (D5), and compared their economic performance. An acidic biotrickling filter (BTF) was operated continuously for 90 days to investigate its performance under different H2 S and D5 concentrations. Meanwhile, commercial iron-oxide-based adsorbents (IOBAs) and activated carbon (AC) were used in adsorption filters for H2 S and D5, respectively. The results show that in terms of the ratio of D5 and H2 S concentration (RD5:H2S ) and pH of the recycling liquid, which are crucial BTF operating parameters, high elimination for both H2 S (1.86 kg/(m 3 ·d)) and D5 (0.282 kg/(m 3 ·d)) was achieved at RD5:H2S of 3.7:16 and pH of 0.86. Economic analysis confirmed that BTF-AC was more profitable than IOBA-AC adsorption over a life span of 10 years because the pre-removal of D5 by a BTF significantly decreased the costs of IOBAs and AC, despite BTFs requiring a higher initial capital investment. In terms of the economic benefit of biogas production of 1200 Nm 3 /h, the competitive annual cost of 90.5 k$/year indicated that BTF was more profitable, yielding both cost saving and the benefit of providing heat. The advantage of BTF-AC adsorption was a more radical D5-abatament, enabling profit by selling the electricity produced from biogas to the grid. Highlights: Economic performance of two biogas purification systems was investigated. The ratio of D5 and H2 S concentration and pH are two crucial parameters of acidic BTF. BTF & AC system is more profitable than iron-oxide-based adsorbent & AC adsorption. Annual cost of acidic BTF was competitive 90.5 K$/year.