Microreactor Approaches for Liquid Fuel Production from Bioderived Syngas −5 m3/h Prototype Development for HTHP Water Gas Shift

Abstract

A lab-scale microstructured reactor was used for investigations on enhancing the H2/CO ratio in synthesis gas from biomass feedstocks via the water gas shift reaction at elevated pressure and temperature. A model mixture of carbon monoxide, carbon dioxide, water, and hydrogen was used to reproduce the typical synthesis gas composition from dry biomass gasification. Catalyst powders were prepared and characterized with regard to a simplified catalyst exchange for scale-up; an incipient wetness impregnation of commercial ceria was applied to compare the performance and characteristics to previously investigated catalyst layers produced by a combined incipient wetness impregnation and sol–gel technology. The catalytic activities of these Pt/CeO2 powders were further compared to a commercial high temperature iron water gas shift catalyst at temperatures of 400 to 600 °C and pressures of up to 45 bar. Increased pressure led again to higher values of CO conversion and to increased formation of hydrocarbons (CH4, C2H6, etc.) and coke. Catalyst coatings revealed a higher catalytic activity than the powders due to their higher surface area. A power law model from literature was adapted to fit the performance of the catalyst layers. This model was used to evaluate the scale-up of a microreactor in the scale of 5 m3/h STP throughput of raw synthesis gas and to potentially confirm the idea of a forced falling temperature gradient for the exothermic shift reaction with the selected catalyst coating.