Oxidative Stability and Cold Flow Properties of Non-Edible Vegetable Oil for Industrial Biolubricant Applications

Abstract

The use of mineral oil-based lubricants is attracting increasing environmental concern. Additionally, mineral oil is non- renewable and subject to high price fluctuation. There is therefore a need to seek alternative sustainable and renewable lubricant base stock. Vegetable oil are thought of as good substitute for mineral oil -based lubricants, but their use suffers setback due to their poor cold flow characteristics and thermo-oxidative instability. The oxidative stability, flash point and cold flow behaviour of castor oil were measured and compared to commercially available mineral oil -based lubricant SAE 20/W50. The castor oil had peroxide value of 8.92 meq/kg, flash point of 2820C, cloud point of -12.40C and pour point of 23.20C. The commercially available mineral oil- based lubricant SAE 20/W50 had peroxide value of 0.99 meq/kg, flash point of 2550C, cloud-point temperature of -18.90C and pour-point temperature of 24.10C. The castor oil has poor oxidative stability but excellent fire safety and cold flow properties. The - castor oil is a good sustainable and renewable alternative to petroleum oil -based lubricant, however its oxidative stability needs to be improved to increase its shelf life and service life as a lubricant.