| Biogas, produced from anaerobic digestion of cattle manure, is an attractive alternative energy source as it is rich in methane. However, it is necessary to remove hydrogen sulfide from the biogas before it can be used in engines for electricity generation. Currently, large scale biogas systems employ physical adsorbing solvents to upgrade and purify biogas which is not economically feasible for small scale biogas systems. Activated carbon made from anaerobic digestate proves to be an effective adsorbent of hydrogen sulfide because it has minimal operating costs and essentially zero raw material cost. A model is developed to predict the adsorption capacity, carbon bed life span, and breakthrough time for this carbon material. By analyzing the reaction constant, adsorption constant, and degradation constant, adsorption behavior under different operating conditions were studied. The model can be scaled-up to model adsorption for biogas loading rates for small to large scale cattle farms. |
