Experimental Investigation of Photo-Thermal Catalytic Reactor for the Reverse Water Gas Shift Reaction under Concentrated Irradiation

An upscaled photo-thermal catalytic reactor for the heterogeneously catalysed reverse Water Gas Shift (rWGS) reaction is tested under simulated concentrated irradiation. The reactor is equipped with an aperture of 144 cm2 area covered by a quartz window, where it receives irradiation flux densities of up to 80 kW/m2 corresponding to an irradiation power input of 1 kW thereby directly irradiating a RuO2 based photo-thermal catalyst that is deposited on a porous support. The system was operated under simulated concentrated sunlight for a total of 45.5 h with 35.4 h of chemical operation. A peak CO production rate of 1.6 mol/h was achieved with an average light concentration factor of 80 in the centre of the catalyst layer. This corresponds to a solar-to-chemical efficiency – defined by the ratio of the product of molar CO production rate and reaction enthalpy for the rWGS reaction and the irradiation power input – of 1.69 %. A calculation approach to determine the catalyst surface temperature under irradiation was introduced and utilised for performance analysis leading to the discussion of design modifications and operating strategies towards performance enhancement.