Novel non-concentrated solar collector for solar-powered chemical reactions
The purpose of this study is the proof that nonconcentrating solar-thermal collectors can supply the thermal energy needed to power endothermic chemical reactions such as steam reforming of alcoholic (bio-) fuels. Traditional steam reformers require the combustion of up to 50% of the primary fuel to enable the endothermic reforming reaction. Our goal is to use a selective solar absorber coating on top of a collectorreactor surrounded by vacuum insulation. For methanol reforming, a reaction temperature of 220-250°C is required for effective methanol-to-hydrogen conversion. A multilayer absorber coating (TiNOX) is used, as well as a turbomolecular pump to reach ultra-high. The collector-reactor is made of copper tubes and plates and a Cu/ZnO/Al 2O3 catalyst is integrated in a porous ceramic structure towards the end of the reactor tube. The device is tested under 1000 W/m 2 solar irradiation (using an ABB class solar simulator, air mass 1.5). Numerical and experimental results show that convective and conductive heat losses are eliminated at vacuum pressures of <10-4 Torr. By reducing radiative losses through chemical polishing of the non-absorbing surfaces, the methanol-water mixture can be effectively heated to 240-250°C and converted to hydrogen-rich gas mixture. For liquid methanol-water inlet flow rates up to 1 ml/min per m2 of solar collector area can be converted to hydrogen with a methanol conversion rate above 90%. This study will present the design and fabrication of the solar collector-reactor, its testing and optimization, and its integration into an entire hydrogen-fed Polymer Electrolyte Membrane fuel cell system. Copyright © 2013 by ASME.
Asme 2013 7th Int. Conf. on Energy Sustainability Collocated With the Asme 2013 Heat Transfer Summer Conf. and the Asme 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology, Es 2013
International Standard Book Number 13 (ISBN-13)
Digital Object Identifier (DOI)