Removal of Contaminant Gases from Biogas by Chemical Purification Processes

ABSTRACT Biogas generated from biomass sources can be utilized as a renewable fuel to achieve ambitious targets as biofuel for internal combustion engines. This process was achieved in combined absorption and adsorption chemical way. The absorption and adsorption were employed by aqueous solutions of Ca(OH)2 and Fe0, activated carbon, silica gel and Na2SO4 respectively. Test results revealed that the aqueous solution used was effective in reacting with CO2 in biogas (over 90% removal efficiency), creating CH4 enriched fuel in Test 1 and Test 2. H2S was reduced to 12 ppm and 47 ppm with the derived nanomaterial activated carbon and Fe0 adsorbent respectively which are below the standard required limit. The maximum 98 % H2O concentration removal efficiency was realized in T1 by treating silica gel. This study represents a 60% improvement in the CH4 content from the initial average value of 60% to above 95% for both tests. Saturation was reached in about 180 min, 200 min and 180 min treated with Ca(OH)2, Fe0, activated carbon, silica gel and Na2SO4 for removal of CO2, H2S and H2O respectively. This technique proved to be a promising and feasible system for biogas purification.