Requirements for biogas desulfurization

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As an emerging energy source, biogas is being used more and more widely. China’s environmental protection standards stipulate strictly that when using biogas as an energy source, the H2S content in the biogas gas must not exceed 20 mg/m3. H2S must be removed as much as possible, whether in industrial or commercial gases. When biogas is produced by anaerobic fermentation systems, especially during medium- or high-temperature fermentation, it contains large amounts of H2S. Due to the large amount of water vapor present in biogas, water, together with H2S in the biogas, accelerates the corrosion and clogging of metal pipes, valves, and flow meters. Furthermore, SO2 generated upon the combustion of H2S combines with water vapor in the combustion products to form sulfurous acid, which causes corrosion on the metal surfaces of equipment. It also leads to pollution of the atmospheric environment and has an adverse effect on human health. Therefore, H2S must be removed from biogas before it is used. Commonly used biogas desulfurization methods in the industry include dry desulfurization, wet desulfurization, biological desulfurization, and other such techniques.