Carbon Footprint in Bovine Fat Biodiesel Synthesis - Comparison Using Methanol or Ethanol

Abstract

Climate change makes the comparison of strategies to mitigate environmental impacts in the production of catalyzed biodiesel derived from animal fat waste a necessity. Transesterification of Bovine Kidney Fat (BKF) into biodiesel is feasible, but the utilized inputs can incur a substantial environmental cost, such as Carbon Footprint (CF). The utilization of Ethanol as a reagent for the transesterification of BKF presents a viable alternative that could influence the Life Cycle Assessment (LCA) of Biodiesel and reduce its CF. This study compares the CF for the LCA of producing 1 kg of Biodiesel for a 1-6 Methanol-BKF and 1-9 Ethanol-BKF ratio, catalyzed by Sodium Hydroxide (NaOH) and Potassium Hydroxide (KOH) at 0.35% at 60°C. The LCA was initially defined following ISO 14067:2018 standards, and subsequently, the Greenhouse Gas (GHG) Emission Inventory was conducted for each stage of Biodiesel manufacturing. Ultimately, CF was calculated using CCalC2 software for the two examined conditions. Five processes were identified in the manufacturing of Biodiesel from BKF in the LCA stages. The CF for Biodiesel derived from BKF with Methanol is 4.36 kg CO2eq/FU, whereas the CF for Biodiesel derived from BKF with Ethanol + 5mol H2O is 0.246 kg CO2eq/FU. Enhanced environmental performance was evidenced using Ethanol + 5mol H2O for the LCA in BKF Biodiesel manufacturing, exhibiting a 1772.35% improvement over Methanol.