Valorization of Biodiesel Production: Focus on Crude Glycerine Refining/Purification

Biodiesel production in Nigeria is gaining more level of awareness but the cost of production is still on the high side. This is largely due to the cost of raw materials, mainly vegetable oil or fat. Fortunately, a very efficient way to reduce this cost and increase profitability is the purification of the crude glycerol by-product of the biodiesel production process. Hence, this research was carried out using crude glycerol from biodiesel production of Neem Seed Oil (N. S. O.) and Waste Cooking Vegetable Oil (W.C.V.O) and it also provides a cost effective, domesticated process technology for the purification of the crude glycerol from any biodiesel production facility.

Neutralization and phase separation was carried out using dilute phosphoric acid, followed by separation of the glycerol rich layer, concentration and methanol recovery, glycerol extraction using iso-propanol (IPA) and then colour removal with activated charcoal. The effect of pH during neutralization on the purification level was investigated using a pH range of 3.0 – 7.0 at steps of 0.5. The optimal pH was found to be about 6.5 for both crude glycerol sources. Also, the IPA: glycerol ratio was varied using 1:1, 1:2, 2:1, 3:1 and extraction was found to be optimum at 2:1. (v/v) to achieve average glycerol purity level of about 97%.

Both the refined glycerol and crude glycerol samples were analyzed using the Gas Chromatograph Mass Spectrometer (G. C. M. S.). Other analyses were also extensively carried out and all conformed to quality standard.