Utilization of biogas–diesel mixture as fuel in a fertilizer pelletising machine for reduction of greenhouse gas emission in small farms

Many commercial pig farms in Thailand have used pigs' dropping and sewage to produce biogas, which reduces odor around the farms. However, small farms have excess biogas since the biogas is only used for household purpose. Therefore, the excess gas is normally released to the atmosphere and consequently exacerbates the greenhouse effect. Thus this project is aimed to use the excess biogas in a diesel engine for a fertilizer pelletising machine. The performance of the fertilizer pelletising machine and greenhouse gas emission reduction were analyzed.The pelletiser machine run by diesel engine was partly powered by the excess biogas. A reduction in diesel use of 63% was achieved compared to the control case where only diesel was used. The reduction of greenhouse gas due to the utilization of methane was equivalent to 13 tCO2/year/farm. Moreover, the feasibility study revealed that this project had a payback period of 0.46 years and an IRR of 210.4%.

► In small pig farms, excess produced biogas is simply released to the atmosphere.
► This project is aimed to reduce biogas emission by using a fertilizing machine.
► Biogas can be used to replace diesel fuel at a maximum of 63% replacement.
► The reduction of greenhouse gas emission was equivalent to 13 tCO2/year/farm.