Glycerol is a waste resource generated in the production of biodiesel from triglycerides; a component of oils and fats. The increasing demand at the government level for a bio-sourced component to automotive fuels has driven the generation of a surplus of glycerol. Glycerol in a purified state has many applications in food and pharmaceutical industries, however, the waste glycerol from biodiesel is a majority portion of a crude mixture. This mixture can contain up to 30 percent water, salts, methanol and partially converted triglycerides. Presently, there is little demand for this crude glycerol and as a result remains waste and is often combusted as a disposal method.
Recently, a number of research groups have attempted to convert glycerol to useful products at a rapid pace. One of the most successful approach to have emerged has been the conversion of dilute glycerol over acid catalysts to form acrolein, a precursor to acrylic acid used in the resin and plastics industry. Several heterogeneous, acid catalysts have proved highly active and selective to acrolein. This approach is desirable, however, the reactions completed thus far have used a purified source of glycerol and the dilution levels have been lower than the comparable crude solutions produced industrially.
As an alternative to solid acid catalysts we have developed a process which can produce methanol in relatively high yields over metal oxide catalysts which have either basic or redox active surfaces. Presently, methanol is produced via synthesis gas, this two stage method of methanol production which at over 25 million tonnes per annum and is costly, energy intensive and wasteful on an industrial scale. Crucially, crude glycerol solutions which have been simply filtered and slightly diluted can be used furtherextending the potential application of this technology. The catalyst operate up to temperatures of 480°C and under atmospheric pressure of an inert gas and under these conditions production of by-products can be reduced significantly. The results obtained pave the way for commercial implantation where the reaction products comprised principally of methanol can be blended with petroleum. Such a process has the potential to dramatically alter current approaches to increase the bio-derived competent of automotive fuels.
Presently, the technology has been granted a US patent and work is under way to further develop the catalyst and process to bring it to market. Successful commercialisation would deliver an innovative, environmentally conscience approach to reduce waste in the significant and rapidly emerging bio-fuel sector.
