Crude biodiesel refining using membrane ultra-filtration process: An environmentally benign process

Ceramic membrane separation system was developed to simultaneously remove free glycerol and soap from crude biodiesel. Crude biodiesel produced was ultra-filtered by multi-channel tubular membrane of the pore size of 0.05 μm. The effects of process parameters: transmembrane pressure (TMP, bar), temperature (°C) and flow rate (L/min) on the membrane system were evaluated. The process parameters were then optimized using Central Composite Design (CCD) coupled with Response Surface Methodology (RSM). The best retention coefficients (%R) for free glycerol and soap were 97.5% and 96.6% respectively. Further, the physical properties measured were comparable to those obtained in ASTMD6751-03 and EN14214 standards.