Biogas Purifier for Japanese Rural Areas

Abstract

Currently, the biogas produced by biogas plants at dairy farms in Japan is a carbon-neutral energy. However, utilization of biogas has thus far been restricted solely to the farms where it is produced because there is no effective method of transporting unused biogas. Thus, there is a need to establish practical methods for biogas refinement and transport from operating systems. In this study, a biogas refining-compressing-filling facility using a gas membrane that would allow the use of surplus biogas produced by privately owned biogas plants was manufactured. Furthermore, field tests of biogas utilization systems (BGUS) made up of equipment that could use purified gas obtained from such a facility were performed. Finally, the possibility of a regional purified biogas system of Japan was validated in rural areas. The refining-compressing-filling facility was able to achieve a biogas Wobbe index of 49.2–53.8 and a combustion rate equivalent to 34–47 m/s. The total carbon load of the common portions of the BGUS was 102 t-CO₂eq. Compared with the carbon load of the common portion of the biogas plant before introduction of the BGUS and of the gas utilizing equipment inside and outside the farm production system (209 t-CO₂eq), a reduction of 107 t-CO₂eq was achieved. The area’s carbon dioxide emissions could be reduced through the standardization of biogas products through refinement; this would allow for the export of biogas outside of the system for use in common gas appliances. Currently, purified gas is locally produced and consumed as a source of carbon-neutral energy on dafacility was able to achieve a biogasiry farms and adjacent residences. Packing the purified gas into tanks and supplying it to the town create the possibility of further reducing the carbon emissions of rural areas.