The field of chemical engineering was built around the processing of petroleum into fuels and chemicals, and it is perhaps the field's biggest challenge to transition the industry's feedstocks to non-fossil sources of carbon. The only possible non-fossil carbon feedstocks are carbon dioxide and biomass. In this poster, I will report on two processes that I have worked on that offer innovative solutions to this challenge.
No material has been shown to (photo-)electrochemically produce hydrocarbon fuels from CO2 both selectively and efficiently. Producing fuels and chemicals from CO2 in a such a process would produce an ideal storage medium for intermittent renewable energy sources such as solar and wind. In my postdoctoral work at Stanford and at DTU, we are unraveling mechanistic details of how the selective catalysts (primarily copper and its alloys) and the efficient catalysts (primarily the active centers of enzymes) operate. Through these insights, we are designing future catalysts for efficient and selective CO2 fixation to hydrocarbon fuels and chemicals.
In the second part of the poster, I will report on a novel biomass process that we developed while I was in my graduate studies at MIT. Current biofuels processes suffer from low efficiencies and produce fuels that are chemically distinct from their conventional analogs. In collaboration with co-workers in the metabolic engineering laboratory, we developed processes by which efficient fermentations could be employed to produce partially deoxygenated intermediate compounds. In a subsequent step, these intermediate compounds are hydrothermally reformed in sub- or supercritical water. This results in the selective production of either propane or propylene, depending on the pathway chosen. Since hydrothermal reforming is capable of being undertaken directly on the fermentation broth and the products (propane and propylene) are immiscible with the aqueous effluent, no costly distillation step is necessary to separate them. This is expected to result in an efficient, selective process towards producing conventional fuels from biomass feedstocks.