Published August 2007
The availability of large amounts of by-product glycerin from biodiesel production has encouraged the development of technologies that can use glycerin as a raw material for producing large volume value-added products. One such product is the chlorinated C3 epoxide, epichlorohydrin. The conventional method for making this material involves a three step process that uses propylene and chlorine to provide the chlorinated C3 backbone. It has also been known for decades that glycerin can be made to react with HCl to form an intermediate dichlorohydrin which can then be converted to epichlorohydrin. But this chemistry has not been used commercially to any significant extent because of the high cost of glycerin compared to propylene. The availability of bio-based glycerin and the tight propylene market has reversed this situation.
Recently published world and U.S. patent applications disclose technologies that claim improvements to the old art for producing epichlorohydrin from glycerin. In this Review we describe patent applications issued to Aser SRL, Dow Global Technologies, and Solvay Societe Anonyme and use some of the information provided to evaluate the economics of producing epichlorohydrin from crude glycerin generated in a biodiesel plant.
Capital investment and production cost estimates are developed for a base case plant producing 100 MMLB/YR of epichlorohydrin from crude glycerin. Design of the reaction sections of the plant is based on information disclosed in the Dow patent application.
Estimated capital investment (battery limits and offsites) for the base case plant is $66 MM. Cash cost is 43.0 cents/lb epichlorohydrin; net production cost is 52.6 cents/lb; product value including a simple 25% before tax ROI is 69.1 cents/lb.
The current market price for epichlorohydrin is ~1 $/lb. Based on the estimated production economics it appears that the bio-derived glycerin-to-epichlorohydrin process is formidable competition to existing production.