DESIGN, TESTING, AND EVALUATION OF A HYDROUS BIOETHANOL DISTILLER FOR THE PRODUCTION OF FUEL-GRADE ALCOHOL FROM NIPA SAP (Nypa fruticans)

Abstract. To help reduce dependence on fossil fuels for mechanized farm operations, we developed and tested a distiller using fermented nipa sap with 7% alcohol content and diluted nipa fermentation liquor or crude bioethanol (15% concentration) to produce fuel-grade bioethanol for small spark-ignition engines.

The distiller consisted of an internally heated boiler, packed bed column, and water-trickling condenser. Its heat source was a moving-bed rice husk gasifier using 17–28 kilograms of rice hull per hour. The distiller produced 14–15 liters of hydrous bioethanol (93–95%) using 200 liters of fermented nipa sap for 6–7 hours distilling period. Using fermentation liquor, on the other hand, increased its capacity to 18–20 liters of bioethanol (92%) in five hours. Distilling rate varied from 3.4–3.7 liters per hour, using fermented sap, to 5.0 L h^-1, using diluted fermentation liquor.

Cost analysis showed that the USD2500 (PHP123,000) distiller could process fermented nipa sap and diluted fermentation liquor into hydrous bioethanol at USD 0.53-0.75 (PHP26.40–37.70) per liter and USD0.20–0.35 (PHP10.50–17.60) per liter, respectively. Hydrous bioethanol (92–95%) was found suitable as fuel for retrofitted gasoline engines powering a water pump, brush cutter, and pump boat. Distiller size can be scaled up to further increase capacity and reduce production cost of fuel-grade bioethanol.