Hydrogenation of CO2 over Fe-K based catalysts in a fixed bed reactors at elevated pressure

Abstract

Catalytic hydrogenation of CO2to produce hydrocarbons was conducted in a fixed bed reactor (1.6 cm-IDx60 cm-High). Fe-K based catalysts (KRICAT-A, B) were used for more than 850 hours to maintain CO2 conversion level up to 30 C-mol% in the fixed bed micro-reactor. Effects of operating variables on the CO2 conversion, hydrocarbon yield and its selectivity were investigated. The CO2 conversion and total hydrocarbon yield increased with increasing reaction temperature (250-325 °C), pressure (0.5-2.5 MPa) and H2/CO2 mol ratio (2-5); however, they decreased with increasing space velocity (1,000-4,000 ml/gcathr) in the reactor. The selectivities of liquid products increased with increasing reaction pressure; however, they decreased with increasing temperature, space velocity and H2/CO2 ratio. From the results of an experimental study, optimum operating conditions for the maximum yield of olefinic liquid products were found as T=315 °C, P=1.5 MPa, SV=2,000 ml/gcathr and H2/CO2 ratio=3 in the fixed bed reactor within these experimental conditions.