Electricity generation from the biogas in pig farms has been promoted by the government in Taiwan for quite a long time; however, it has encountered obstacles because the equipments easily corrodes by untreated biogas containing hydrogen sulfide that produced by the anaerobic digestion. The project is aimed at developing the nanoscale zero-valent iron coated filter as a novel dry desulfurization technology to remove the hydrogen sulfide from the biogas. In this study, hydrogen sulfide presented in both aqueous phase and gas phase was examined. Experiments included laboratory and field tests. Three types of adsorbents were used: nanoscale zero-valent iron (nZVI), nZVI coated granular activated carbon (GACnZVI) and nZVI coated crashed activated carbon (CACnZVI). Results can be listed as three parts: (1) hydrogen sulfide removal in the aqueous phase using adsorbents in the laboratory, (2) hydrogen sulfide removal in the gas phase using adsorbents in the laboratory, and (3) hydrogen sulfide removal in the gas phase using adsorbents in a pig farmer in Pingdong. It was found that the increase in pH decreased the sulfide removal capacity in the use of nZVI. Nevertheless, the use of CACnZVI the pH effect becomes insignificant at near neutral pH. The average adsorption capacity was in the range of 360-895 mg/g. In the gas phase study, increasing the numbers of filters increased the operation spin for more than 3 times compared to the singal filter. The use of CACnZVI enhanced the sulfide removal capacity by a factor of 3-4. A successful model system of the CACnZVI filter has been confirmed by the results obtained at the Lin Chu-May pig farm in Pingdong city. The sulfide removal capacity was determined to be about 75.6 mg/g, which is greater than that obtained in the laboratory. Based on the cost-effective analysis, the media cost of CACnZVI is 106,000 NTD/Kg H2S and 10,050 NTD/Kg H2S for gas and aqueous phase treatment, respectively.

Biogas electricity;nanoscale zerovalent iron;hydrogen sulfide