Most biodiesel in the USA is made by reacting vegetable (soy) oils with methanol in the presence of a catalyst by a chemical process known as transesterification. The reaction process forms two products: methyl ester (which is the bio-diesel) and glycerol. To force the reaction to completion, an excess amount of methanol, 20-100% more methanol than is stoichiometrically required for reaction, is used. The two products are separated by decanting or centrifuge, and the excess (un-reacted) methanol is divided between the two products: approximately 40% with the biodiesel, and 60% with the glycerol.
Methanol Recovery from both the biodiesel and glycerol products is imperative to the economics of any biodiesel production facility. The preferred result is to recover the methanol in a form for re-use in production to reduce the overall methanol costs.
Wintek has expertise designing systems to recover methanol in an energy-efficient and cost-effective way. Flash towers supported by a biodiesel sealed liquid ring vacuum system to separate methanol from bio-diesel and glycerol. The flash tower maintains a set temperature and pressure which enables the vaporization of methanol while the bio-diesel/glycerol remains a liquid. As a vapor, the methanol travels to the top of the tower and discharges to the solvent recovery condenser and receiver. The vapor methanol is condensed and recovered in the receiver tank for re-use. The bio-diesel/glycerol falls to the bottom of the tower and is pumped out to a desired location by a transfer pump.
Wintek utilizes the customers clean biodiesel as the sealant in the liquid ring pump in an air-cooled sealant recirculation system. This design eliminates the utility cost of providing the vacuum pump with cooling water as well as fresh sealant oil. Wintek’s expertise in this field has provided numerous customers with methanol recovery systems that have helped reduce operating costs.