BIOFUELS-UK, cilt.12, sa.6, ss.679-688, 2021 (SCI-Expanded)
Use of abundant indigenous energy crops for biofuel production contributes to enhance the economy and reduce the dependence on fossil fuels. This article aims to shed light on two energy crops available in Pakistan; castor (Ricinus communis L.) and cottonseed (Gossypium hirsutum L.). Although castor has excellent oil content (54%), its high viscosity is not acceptable. Therefore, pre-blending with cottonseed oil was proposed. Physical and chemical properties of crude oils, pure biodiesels and binary blends besides fatty acid composition and degree of unsaturation were analyzed. Biodiesels were checked for quality parameters within limits of American Society for Testing Materials (ASTM) and European Standards. Improvement in kinematic viscosity and density of castor biodiesel were noticed following this concept. Moreover, the developed empirical formula indicated that an optimized blending ratio of 93.86% cottonseed oil and 6.14% castor oil accomplished biodiesel yield of 91.12%, kinematic viscosity of 6 mm(2)/s and cetane number of 48.79, respectively, which all satisfy ASTM D6751. This technique also indicated that pre-blending can raise the ester content of castor biodiesel. In conclusion, it is recommended to adopt the concept of pre-blending to improve the quality of biodiesel and thus the engine and emission performance in compression ignition engines.