PNNL

Abstract

Ethanol is a promising platform molecule for producing of a variety of fuels and chemicals while reducing the carbon footprint of production. With airlines committed to reduce their carbon footprint by half within the next three decades, producing jet fuel from renewable ethanol feedstock is of particular interest. State-of-the-art alcohol-to-jet technology requires multiple process steps based on catalytic dehydration of ethanol to ethylene, followed by a multi-step oligomerization including n-butene formation, and then hydrotreatment and distillation. Recently, we reported on an Ag/ZrO2/SBA-16 catalyst system that is very effective for directly converting ethanol into to n-butene (1- and 2-butene mixtures), thus eliminating the need for the energy intensive ethanol dehydration to ethylene step. While exceptional n-butene-rich olefin selectivity (i.e., 88% at full conversion) was obtained over Ag/ZrO2/SBA-16, the catalyst suffered from deactivation with time-on-stream. Here, we report on a new improved catalyst formulation consisting of Cu/ZrO2/SBA-16 that provides enhanced stability as compared to Ag/ZrO2/SBA-16. While operating under severe operating conditions for 120 hours on stream (i.e., 400°C, weight hour space velocity = 1.8 hr-1), a limited loss of conversion