Experimental research of biogas production by using a three-stage semi-continuous bioreactor with modified mixer

Abstract

The efficiency of a semi-continuous three-stage bioreactor and application possibilities of a chicken manure substrate with birch wood biochar additive (10% by a dry mass) were investigated in this work to evaluate a possible increase in biogas yield, CH(4)concentration and to reduce CO(2)and H2S concentrations. A biogas purification filter-adsorber has been investigated in order to efficiently purify biogas from H2S and CO2. A chicken manure substrate with an organic load of 100.0 g VS/L was used for testing. Studies have shown that the application of the birch wood biochar additive increases the yield of biogas by 12.4%, the concentration of CH(4)by 5.8%, and reduces the concentration of CO(2)and H2S by 4.0% and 17.5%, respectively. The intermediate chamber of the bioreactor, used for the optimization of the substrate, reduces the dissolved oxygen by 80.5%. Homogeneous mixing of the substrate with a modified complex mixer increases the yield of biogas by 42.3%, CH(4)concentration by 14.3%, reduces CO(2)and H2S concentrations by 25.5% and 45.6%, respectively. The efficiency of the biogas purification filter-adsorber was determined (99.2% for purifying biogas from H2S and 19.2% for purifying biogas from CO2).