Ni−Mg−O Catalyst Driven by Direct Light Irradiation for Catalytically-Activated Foam Absorber in a Solar Reforming Receiver-Reactor

Abstract

A nickel−magnesia solid solution Ni−Mg−O was examined as a catalyst for solar CO2 reforming of methane. The activity was tested in a laboratory-scale transparent (quartz) reactor under direct irradiation of the catalyst by high-flux visible light from a sun-simulator. The 8−11 wt % Ni−Mg−O catalyst gave the high reforming activity or about 100% of chemical conversion, with little coking, under a high-flux irradiation of 890 kW m-2 and at a short residence time of about 0.15 s while passing a 1:1 CH4−CO2 gas mixture at 1 atm. The comparison of the activity data with those obtained in a light-irradiated, nontransparent (steel) reactor showed that the intensification of heat supply by the direct light irradiation of the Ni−Mg−O catalyst leads to considerable reaction rate enhancement. Applying this Ni−Mg−O catalyst, a new type of “catalytically activated” ceramic (alumina) foam absorber was prepared and tested on activity in a laboratory-scale volumetric receiver-reactor using the sun-simulator. This new absorber may be applied in solar receiver-reactor systems for converting concentrated solar high fluxes to chemical fuels via endothermic natural-gas reforming.

Fundamentals and Applications of Structured Ceramic Foam Catalysts

“…Miscellaneous Processes. Other processes involving ceramic foam catalysts that have received recent attention include selective methanol oxidation, 119 methanol to olefins, 120 diesel exhaust gas, 121 the destruction of chlorinated hydrocarbons by steam refoming 20 and photocatalysis, 122 and countercurrent twophase flow reactors. 123…”

Steam reforming of methane on a Ru/Al2O3 catalyst promoted with Mn oxides for solar hydrogen production

“…Numerous studies have been focused on developing solarpowered reactors with direct solar irradiation of the catalyst. [1][2][3][4][5][6][7][8] A directly irradiated annular pressurized receiver (DIAPR) with ceramic pins absorber 9 was developed recently for operation at high temperatures and pressures. 10 The test results for heating air at various irradiation conditions and flow rates are reported by Kribus et al 11 Exit air temperatures of up to 1200 uC and an operating pressure of 17-20 bar were obtained.…”

Sequential separation-driven solar methane reforming for H2 derivation under mild conditions

“…[13][14][15][16][17] It ideally affords high solar-to-fuel efficiencies due to the conversion of the entire solar spectrum to supply heat for the reaction. Research efforts mainly focus on solar receivers/ reactors, 9,15,18,19 catalyst bed structures [20][21][22] and novel cycling approaches [23][24][25][26][27] for improving conversion performance and reducing temperatures. As SMR is generally considered as a high-temperature (e.g., 800-1000 1C) reaction, the most commercially developed parabolic trough solar collectors 28,29 are regarded unsuitable for solar SMR, since the temperature range (o550 1C) is too low to attain meaningful methane conversion.…”

“…13–17 It ideally affords high solar-to-fuel efficiencies due to the conversion of the entire solar spectrum to supply heat for the reaction. Research efforts mainly focus on solar receivers/reactors, 9,15,18,19 catalyst bed structures 20–22 and novel cycling approaches 23–27 for improving conversion performance and reducing temperatures. As SMR is generally considered as a high-temperature ( e.g.…”