An Investigation of the Parameters Affecting Biodiesel Fuel Waterwashing



Waterwashing or biodiesel purification is one of the steps in biodiesel fuel processing. Waterwashing of the fuel is an indispensable processing stage, due to the presence of impurities in the fuel. In this research work, some of the effective parameters in biodiesel waterwashing and the optimum conditions which lead to economy in time and cost of waterwashing were investigated. The effective parameters investigated were: temperature, water consumed per batch of fuel, as well as the waterwashing methods namely: mixing, bubble washing, and mist circulation. Test results indicated that temperature affects waterwashing of the fuel most. The minimum time taken for waterwashing, the minimum detergent and moisture remaining in the washed fuel, and the minimum water used up in the process of waterwashing were all obtained when doing the waterwashing at a temperature of 60°C. An increase in the quantity of water used in washing each batch of fueld would result in a decrease of detergent and moisture residue in the fuel, but of course this would be accompanied by a larger quantity of water consumed in the process. Results indicated that mist circulation of waterwashing methods not only takes up less water than the other two methods, but also leaves less such impurities as detergent and catalysts in the final fuel. The amount of soap content after waterwashing through mist circulation method was 0.0283 ppm at 60°C, while they were 0.086 and 0.065 ppm at the same temperature for bubble washing and mixing methods respectively. Waterwashing time taken in mist circulation method was less than that in the other two methods. The average required time for mixing, bubble washing and mist circulation methods at 20°C were 93, 83 and 73 minutes respectively.