(354c) Ethylene Oxide Production without CO2 As Byproduct: Is the Homogeneous H2O2-Based Catalytic Process Practically Viable?

The novel liquid phase ethylene oxide (EO) technology developed at CEBC entails the transport of ethylene from the gas phase into the aqueous phase containing the dissolved H₂O₂ oxidant, methyl trioxorhenium catalyst, and pyridine N-oxide promoter in methanol co-solvent. The ethylene undergoes epoxidation to form corresponding epoxide with no detectable CO₂ formed as byproduct.¹ For, a batch residence time of 1 h, the EO yield and selectivity are 48% and 99+%, respectively. Further, the EO productivity 0.7-4.4 of [g EO/(g Re)/hr] in the CEBC process compares with the EO productivity of 2.2-4.1 of [g EO/(g Ag)/hr]. In this talk, we present a comparative techno-economic analysis benchmarked against the conventional EO technology. Two case studies are performed to study the effect of various parameters (such as source of the oxidant, mode of removing the heat of reaction and recovery/decomposition of the H₂O₂ oxidant) on the economic viability of the CEBC process thus identifying the major economic impact drivers. Further, the environmental performance of the proposed process is compared against the conventional EO technology in a cradle to gate analysis performed using the GaBi software.² The reduction in GHG emissions and other adverse environmental effects due to the conservation of ethylene feedstock, elimination of CO₂ byproduct and easy separation of the products and byproducts from unreacted reactants will be quantified and compared with the environmental footprint of H₂O₂ production. These results along with process development issues such as immobilization of MTO catalyst onto a soluble polymer support, and its stability and durability will be presented and discussed.

 References:

1. Lee, H-J., et. al., Towards a CO₂ -free ethylene oxide process: Homogeneous ethylene oxide in gas-expanded liquids. 2010. 65, 128-134.
2. GaBi software, 4.0; PE International: Germany, 2011.