Methanol recovery from biodiesel and glycerol products is imperative to the economics of any biodiesel production facility. Some facilities dispose of the used methanol; however, the recovery and reuse of methanol is possible. The cost of methanol can become quite high, so it is necessary to recover as much as possible.
Methanol in the Biodiesel Industry
Reacting vegetable (soy) oils with methanol in the presence of a catalyst results in the production of biodiesel. Most biodiesel made in the USA utilizes this process. For instance, this chemical process is known as transesterification. The reaction process forms two products: methyl ester (which is the bio-diesel) and glycerol. An excess amount of methanol forces the reaction to completion. For example, this amount usually ranges from 20-100% more methanol than required for reaction. Decanting or centrifuging separates the two products. The excess (unreacted) methanol is divided between the two products: approximately 40% biodiesel, and 60% glycerol.
For instance, flash towers supported by a biodiesel-sealed liquid ring vacuum system separate methanol from bio-diesel and glycerol. Firstly, the flash tower maintains a set temperature and pressure around the vapor pressure of methanol. This allows the vaporization of methanol while the biodiesel and 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. Next, the receiver tank collects the condensed methanol. The biodiesel/glycerol falls to the bottom of the tower. Finally, a transfer pump moves the liquid to a desired location.
Wintek’s Methanol Recovery Units
Wintek-designed methanol recovery systems are an energy-efficient and cost-effective way to minimize operating cost. 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.