SYNTHESIS, CHARACTERISATION OF BIO- ADDITIVES FOR PERFORMANCE STUDY OF BIO-LUBRICANTS

Abstract

Stringent global environmental regulations have spurred research into alternative fuels. There had been a total of 216 medium (7-700 tonnes) oil spills and 55 large (> 700 tonnes) oil spills in the environment from 2000 to 2023, primarily caused by human negligence. These spills have significantly disrupted ecosystems, harming plant, animal, and human life. Despite its widespread use in automotive engines due to its availability, cost-effectiveness, and performance, mineral oil poses severe environmental challenges and is derived from non- renewable resources. This underscores the urgency of exploring alternative lubrication solutions. The environmental pollution caused by mineral oil-based lubricants, coupled with the depletion of petroleum reserves, has driven research into biolubricants. Biolubricants are the lubricants derived from renewable sources such as vegetable oils, animal fats, and synthetic esters. Biolubricants offer several advantages, including superior viscosity, biodegradability, and reduced toxicity when compared to petroleum-based lubricants. In the presented study, an apricot oil based biolubricant was produced to determine its tribological performance compared to the mineral oil based lubricant. To assess the performance of apricot oil as a lubricant, various blends of apricot oil- based biolubricants and mineral oil-based lubricants were tested using the Four-ball tester and High Temperature Pin-on-disc Tribometer. These tests evaluated parameters like friction reduction, wear prevention, and durability under high pressure (~ 4.45 bar) and high temperature (~150ᵒC) conditions. The results revealed that pure apricot oil-based biolubricants exhibited higher wear and friction coefficients compared to standard mineral oil lubricants like 15W40 or SAE40. However, an optimized blend (70% 15W40 oil and 30% vii apricot oil biolubricant) demonstrated less coefficient of friction and wear rate over either component used individually. Further testing on a journal bearing test rig (TR-660) confirmed that the apricot oil-based biolubricant performed less effectively than 15W40 mineral oil in terms of load-carrying capacity as the generated maximum pressure (~ 1.21 MPa) for biolubricant is less than that of 15W40 oil (~ 3.02 MPa). However, the blend of 15W40 mineral oil and apricot oil biolubricant offered enhanced performance, with the optimal ratio determined to be 70% mineral oil and 30% apricot oil-based biolubricant. The study concludes that while apricot oil-based biolubricants alone may not match the performance of conventional mineral oil lubricants, carefully optimized blends can achieve superior tribological properties. Given the rapid depletion of petroleum reserves and increasing environmental concerns, vegetable and animal oil-based lubricants present a viable, sustainable alternative to mineral oil-based products, contributing to a more sustainable future.