H2S Removal from Biogas using Steel Wool (Fe2O3) Adsorption Combined with Water Absorption: Experimental and Modelling via RSM

Abstract

Hydrogen sulfi de (H2S) is a hazardous gas commonly found in biogas systems; it causes problems in biogas utilization because H2S is highly corrosive to engines, gas storage tanks, and generators. The purpose of this research was to study the biogas upgrading by removing H2S using SCM440 type steel wool (Fe2O3) adsorption combined with water absorption. The biogas upgrading column was operated at a biogas fl ow rate of 0.5–3 l/min, with 10–50 g of treated Fe2O3 adsorbent packed in the middle of the column, and 60–300 ml of water contained at the bottom of the column. The optimal conditions obtained by the RSM for maximum H2S removal were 1 l/min gas fl ow rate, 40 g Fe2O3 and 240 ml water, can be H2S removal of 50.79 g/m3 biogas. Statistical, ANOVA analysis showed that Fe2O3 was the most signifi cant factor followed by water and gas fl ow rate. RSM models showed acceptable prediction of experimental data with maximum R2 value of 0.9804. The Fe2O3 regeneration conditions were examined at air fl ow rates of 1–4 l/min, regeneration times of 1–4 h, and 1–4 repeated uses for H2S removal. The optimum condition was found at a 2 l/min air fl ow rate for 2 h, resulting in a maximum H2S removal of 97.39%. Hence, the Fe2O3 adsorbent combined with water absorption technique has high potential for environmentally friendly and low-cost removal of H2S from biogas at an industrial level.