Co-processing lard/soybean oil over Ca-based catalysts to greener biodiesel

Fatty Acid Methyl Esters (FAME) were produced from lard/soybean oil (SBO) mixtures using a calcium-based heterogeneous catalyst. The green catalyst was prepared by scallop shell calcination at a relatively low temperature (800 °C) to minimize energy consumption. Images from Scanning Electron Microscopy showed agglomerates of a few tens micrometers with rhombohedral calcite crystallites studded with lime. X-ray diffractogram of fresh catalyst presented overlapped patterns of calcite and lime In tested conditions (methanol reflux temperature, 5% (fat mass basis), methanol/fat = 12 molar ratio, and 150 min), the FAME yield reached 95% (mass) with SBO. However, only 75% FAME yield was obtained from pure lard since the active sites of the catalyst were partially neutralized by lard acidity. Co-processing lard/SBO mixtures attenuated the undesirable fat acidity drawback allowing FAME yields around 90% for mixtures containing less than 50% (mass) of lard. The low-grade fat content of the processed mixture showed no impact on the glycerin quality. Co-processing lard/SBO is a smart strategy to overcome the low-grade fats acidity in biodiesel production process thus providing a more sustainable biodiesel production route. [Display omitted] •Biodiesel from lard and soybean oil was produced over Ca heterogeneous catalysts.•Catalyst was prepared by low temperature calcination of Ca rich alimentary wastes.•Biodiesel yield reached 95% for soybean oil and 75% for lard fat over Ca catalyst.•Lard promotes catalyst activity decay (21%) by neutralization of active sites.•Co-processing lard with vegetable oil overcome the fat acidity drawback.