Investigation of the Usability of Glycerol Ethers as Second-Generation Biofuel in Diesel Engine

Abstract

The interest in the use of second-generation biofuels in internal combustion engines which are still largely running with petroleum fuels has been increasing in recent years. In this study, the utilization of glycerol ethers produced by the catalytic conversion of biodiesel-originated glycerol as a second-generation biofuel in a diesel engine was experimentally investigated. The glycerol ethers mixture which was synthesized by the etherification of glycerol with tert- butyl alcohol was blended with the blend of diesel-biodiesel by 2% (v/v) and 5% (v/v). Neat diesel and a diesel-biodiesel fuel blend that contains 80% (v/v) diesel fuel and 20% (v/v) canola oil biodiesel were chosen as reference fuels. The important physical fuel properties of test fuels were determined. It was ascertained that the addition of glycerol ethers to the diesel-biodiesel mixture reduces fuel's viscosity, density, lower heating value, cetane index, and distillation temperatures. It was determined that glycerol ethers decreased the diesel-biodiesel fuel blend's kinematic viscosity by 10-14% and improved the distillation characteristics. The impacts of test fuels on the engine's performance, combustion characteristics, and exhaust emission were scrutinized by carried out the engine tests. It was seen that glycerol ethers increase the specific fuel consumption and HC emission while reducing thermal efficiency, CO, CO2, NOX, and soot (smoke opacity) emission. The most appealing impact of glycerol ethers was witnessed to NOx and HC emissions. Glycerol ethers promoted significant reductions in NOX emissions by approximately 35-77%, however, under the same operating conditions, an increase in HC emissions by approximately 37-142% was observed. In terms of combustion characteristics, the fuel mixture containing 2% (v/v) glycerol ethers performed better than other test fuels. Based on experimental results it was concluded that the glycerol ethers mixture is suitable for use as a second generation biofuel by 2% (v/v) blending ratio with diesel-biodiesel blend in diesel engines.