High-temperature catalysis driven by the direct action of concentrated light or a high-density electron beam

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

“…The sufficient thermal resistance between the wall and the catalyst bed, together with the low thermal conductivity of the catalyst, leads to a limitation of the heat flux. Many investigators previously indicated that the direct heating of catalyst with high-flux light in the transparent reactor could minimize the limitation. ,, Experimental data shown in Figure clearly showed that the intensification of heat supply by the direct heating with high-flux light effectively enhances the reforming rate on the Ni−Mg−O catalyst. Under the high-flux irradiation (FD = 890 kW m -2 ) of the steel reactor, the Ni−Mg−O catalyst inside the reactor was heated to 1124 K at the GHSV value of 8000 h -1 , yielding about 80% of methane conversion.…”

“…Tanashev et al and Aristov et al studied the solar steam reforming of methane under direct irradiation of a commercial Ru-based catalyst by concentrated Xe-arc-lamp or visible light in the experimental scale (the reactor scale and input power levels) similar to the one we used here. They reported the chemical storage efficiencies of 36−74% and methane conversions of 22−83% for the average flux densities (AFD) of irradiation from 130 to 670 kW m -2 using a commercial Ru-based catalyst bed with a 20-mm diameter and a 4−20 mm thickness.…”

Catalytically Activated Metal Foam Absorber for Light-to-Chemical Energy Conversion via Solar Reforming of Methane

“…In the most of the previous literature, the performances of the catalytically active ceramic absorbers in the volumetric receiver−reactors were demonstrated in much larger reactor scales and higher input power levels although light-to-chemical conversions approaching 66% were reported. ,, Thus, their values could not be directly compared with our results in Table . However, Tanashev et al studied the solar steam reforming of methane under direct irradiation of a commercial Ru-based catalyst by concentrated Xe-arc-lamp or visible light in an experimental scale (the reactor scale and input power levels) similar to the one we used. They reported the light-to-chemical energy conversions of 36−74% for the average energy density of radiation ρ = 130−670 kW m -2 using a commercial Ru-based catalyst with a 20-mm diameter (the thickness of the catalyst bed was 4−20 mm).…”

“…The conversion of concentrated solar heat to chemical fuels has the advantage of producing energy carriers for storing and transporting solar energy. − The direct themochemical conversion of solar radiation energy is characterized by ideal high efficiency; its thermodynamic limit for the enthalpy storing is close to 100%. From this point of view of the chemical pathway for this process, solar reforming of natural gas has been investigated as the most promising “solar thermochemical process”. − The following endothermic steam/CO 2 reforming of methane is the basis for upgrading the calorific value of the hydrocarbons, which produce syngas: …”

“…Solar reforming of methane with CO 2 has been investigated for more than 20 years. − Due to the specific properties of a concentrated solar radiation energy source, modifications of the conventionally used reactor system are necessary for the solar reforming process. As a solar-specific reactor for reforming, a direct absorption concept was proposed in which the receiver and reformer are the same unit, which was realized in some solar reforming systems such as directly irradiated “volumetric” reactors developed by the German Aerospace Research Center (DLR) in Germany, Sandia National Laboratories in the United States, and the Weizmann Institute of Science (WIS) in Israel. ,− ,,, In this concept, the concentrated solar radiation passes through a window and is absorbed by an absorber of catalytically active, reticulated ceramic foams which is mounted behind the window.…”