Biological desulfurization process of biogas

摘要

PROBLEM TO BE SOLVED: To provide a biological desulfurizer and a desulfurization method of biogas in which hydrogen sulfide at high load is efficiently processed, internal clogging does not occur, and which are capable of performing processing at a low cost.SOLUTION: A biological desulfurizer comprises: a biogas inflow line 2 for allowing biogas Oa containing hydrogen sulfide to flow in from an end part of a biological desulfurization tower 1; a processed gas outflow line 8 for discharging processed gas Oc to the other end part of the desulfurization tower 1 which is a subsequent stage of a filling layer 1a carrying microorganism; a circulation gas line 9 which circulates a part of the processed gas Oc to an end part of the biological desulfurization tower 1 to which the biogas Oa flows in; and a mixture gas line 5 which mixes the biogas Oa and a part of the processed gas Oc and supplies the mixture to the end part of the biological desulfurization tower 1, in which a gas flow meter 3 is provided for the biogas inflow line 2, a hydrogen sulfide concentration meter 4 is provided for the mixture gas line 5, and an adjusting mechanism 10 of a circulation gas amount is provided for the circulation gas line 9.