Application of Low Pressure Water Scrubbing Technique for Increasing Methane Content in Biogas

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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Universal Journal of Agricultural Research
Abstract
For many developing nations, biogas has traditionally been used for household cooking and lighting. Methane (CH4) content in biogas has to be increased by removing incombustible carbon dioxide (CO2) and potentially corrosive constituents such as hydrogen sulphide (H2S) and moisture. This study set out to increase biogas from 55.8% CH4, 43% CO2, 0.85% oxygen (O2), 75.1 ppm H2S to >80% methane and non-traceable H2S without enhancing raw biogas pressure. By using a single scrubber column and varying water scrubbing system operating parameters of packing material type, packing depth, water and gas flow rates, appropriate parameters for achieving the above objective were determined. The experiments were carried out at an average digester pressure of 1.0589bar. Results show that packing a column with steel-wire mesh to a depth of 0.4m increases the volumetric percentage of CH4 in biogas to >80% for water to gas flow rate ratios 1.9 and above. Increasing the packed depth to 0.8m increases volumetric percentage of CH4 in biogas to 80% at a lower ratio of 0.7. This increase in packed depth resulted in an improvement from 1800 litres to 700 litres of water for every m3 of raw biogas upgraded. However, to achieve >80% CH4 in marble packed columns of similar depths, the water to gas flow rate ratio has to be raised above 2.5.
Description
Keywords
Biogas Upgrading, Methane, Packed Column, Renewable Energy, Water Scrubbing
Citation
Walozi, R., Nabuuma, B., & Sebiti, A. (2016). Application of low pressure water scrubbing technique for increasing methane content in biogas. Universal Journal of Agricultural Research, 4(2), 60-65.DOI: 10.13189/ujar.2016.040206