Production, optimisation and engine characteristics of beef tallow biodiesel rendered from leather fleshing and slaughterhouse wastes

Presently, biodiesel is considered as an effective alternate fuel owing to its high sustainability and robustness. This paper concentrates on the biodiesel production from waste beef tallow rendered from subcutaneous and intramuscular wastes discarded from leather tanneries and slaughterhouses. The maximum fat content was estimated to be 92.5% and 3.05%, whereas maximum rendering efficiency was determined to be 92% and 75% for subcutaneous and intramuscular wastes, respectively. The rendered waste tallow was converted into biodiesel using ethanol as a solvent and l-valine amido ethyl methyl imidazolium bromide ([l-Vaemim]Br) as a novel ionic liquid catalyst. The most optimised reaction parameters are as follows: molar ratio of 1:7.5, catalyst concentration of 20 wt% of tallow, reaction temperature of 75 °C and reaction time of 160 min. Properties of the produced biodiesel have been tested in accordance with ASTM Standards, where the results were found to be within the permissible range. The engine characteristics of biodiesel exhibited increased heat release rate and maximum cylinder pressure, reduced emission levels than compared to ordinary diesel; in addition, its performance characteristics were similar to diesel, thereby making it a suitable replacement for existing fossil fuel.