Study on Upgrading and Further Usage of Glycerol from Waste Water

Waste water from enzymatic biodiesel technology (contained glycerol 5%) is treated as following: Firstly, waste water is filtered with a gauze, add KOH to PH=7~8, and filter to remove salt soap. Secondly, the processed liquid distil at 50°C in Rotary Evaporator vacuum to remove most of water and methanol, then concentrated solution use plinthic flocculants (mass ratio of 100:1), stirring at 70°C to eliminate colloid. Finally, at 180°C, 0.8 kPa to vacuum distil to collect glycerol of purity up to 90.43％.The glycerol react with acetic acid to get glycerol triacetate with phosphotungstic acid catalyst, toluene as water-carrying agent. Thus comes out the yield of more than 90％ glycerol triacetate in 6 hours.