Simplified Simulation Model of a Biotrickling Filter Used for the Removal of Hydrogen Sulfide From Biogas

Abstract

Biogas produced by the anaerobic digestion of waste contains approximately 1000-1200 ppmv H2S, which is toxic and corrosive. It is necessary to remove H2S before using the biogas in further application. Biotrickling filters containing immobilized Thiobacillus sp. on inert packings are used extensively in the industries. The design equations for biotrickling filter are complex in nature. A simplified simulation model has been proposed where the complexity of solving the diffusion equation forming a boundary value problem has been avoided by utilizing an approximate general solution available in the literature for this class of problems. The simplified simulation model has been validated with the experimental data, with the analytical solutions available for limiting cases, and with the numerical solution. The results have been found in good agreement for air-H2S system. Further, the performance of an industrial biotrickling filter, designed to treat 10000 m3.day-1 biogas to reduce H2S concentration from 1200 ppmv to 100 ppmv, has been analyzed by studying the effect of packed bed height, inlet concentration of H2S, empty bed residence time of gas, biofilm thickness and packing size on its removal efficiency by using proposed simplified model.