Techno-economic assessment of biodiesel-derived crude glycerol purification processes†

Abstract

This study presents a comprehensive techno-economic assessment of three glycerol purification processes: Membrane Separation (MBP), Vacuum Distillation (VDP), and Ion Exchange Purification (IEP). The analysis evaluated these processes based on product purity, product recovery, raw material and utility consumption, capital and operating costs, and economic resilience to market fluctuations. IEP achieved the highest glycerol purity (98.75%) and recovery rate (99.00%), followed by VDP (96.91% purity, 94.99% recovery) and MBP (93.92% purity, 86.20% recovery). However, IEP exhibited the highest raw material consumption and liquid waste generation, while VDP demonstrated the most favourable balance between resource utilization and waste production. Economic analysis revealed VDP as the process with the lowest capital cost of 4.44 MUSD and the only profitable process with an annual profit of 0.24 MUSD under the given conditions. Sensitivity analysis, considering variations in raw material prices, utility costs, and product prices, consistently identified VDP as the most economically resilient process. MBP and IEP remained unprofitable across most scenarios, with IEP showing extreme sensitivity to raw material price fluctuations. This assessment provides crucial insights for decision-making in the growing biodiesel industry, emphasizing the need for balancing economic viability with sustainability and adaptability in glycerol purification technologies.