Utilization of Biodiesel-Water Emulsion as Fuel for Crumb Rubber Drying

Crumb rubber is one of the main export commodities in Indonesia from the plantation sector. In the industrial scale, the process of crumb rubber drying generally still uses industrial diesel oil (IDO) as fuel. In order to participate in supporting the government's program for the development of renewable energy, especially biofuels to replace fossil fuels, many research has been conducted regarding the use of biodiesel-water emulsion (W/O) as an alternative fuel for crumb rubber drying. The biodiesel used is a mixture of 70% diesel oil and 30% FAME (B30-water) and a mixture of 60% diesel oil and 40% FAME (B40-water) from crude palm oil (CPO). The use of water as substituent agent for biodiesel is intended to increase fuel economy and minimize NOx and PM emissions which potential to decrease the rubber quality. A homogeneous and stable water biodiesel emulsion (90:10), namely B30-water and B40-water, was obtained by adding 5% emulsifier consisting of a mixture of Span 80 and Tween 80 as surfactants to form a B30-water and B40-water emulsion. Homogenization of biodiesel, water and surfactants mixture using a high-speed mixer (23,000 rpm) for 1-2 minutes resulting homogenous and stable B30-water and B40-water emulsions minimum 24 hours were then used as alternative fuel for crumb rubber drying by direct heating to the rubber surface at a drying temperature of 130-135 °C and drying air rate 1-1.5 m/sec. The results showed that B30-water and B40-water emulsions with a water content of 10% were appropriate to use as alternative fuels for crumb rubber drying. The quality of the dry crumb rubber produced was fulfill the requirement standard according to SNI 1903: 2017.