Abstract
A detailed study of the experimental issues involved in the design and operation of a methanol steam microreformer is presented in this paper. Micromachining technology was utilized to fabricate a metallic microchannel block coupling the exothermic and endothermic process. The microchannel block was coated with a Pd/ZnO catalyst in the reforming channels and with Pd/Al2O3 in the combustion channels by washcoating. An experimental system had been designed and fine-tuned allowing estimation of the heat losses of the system and to compensate for them by means of electric heating cartridges. In this way, the heat necessary for the reforming reaction is provided by methanol combustion, thanks to the temperature and flow cascade controller we developed. Thus, the coupling of both reactions in a block of microchannels without the interference caused by significant heat loss due to the small size of the laboratory microreactor could be studied. Runs of this microreformer device were carried out, varying the deposited catalyst amount, methanol steam reforming temperature and space velocity. When the reforming reaction was compensated by the combustion reaction and the heat losses by the electric heating, an almost isothermal behavior of the microchannel reactor was observed. In the less favorable case, with a 460 mg catalyst load, ΔTMSR was about 8 K and ΔTCOMB was about 16 K. This confirmed good coupling of the methanol steam reforming and the methanol combustion.
Highlights
Hydrogen is a clean fuel that produces only water, electricity, and heat when it is consumed in a fuel cell
We can study the coupling of both reactions in a block of microchannels without the interference caused by the significant heat losses due to the small size of the laboratory microreactor
Regarding the experiments when the reforming reaction was compensated by the combustion reaction and the heat losses by the electric heating, an almost isothermal behavior of the block of microchannels could be seen despite the small-scale problem (Figures 8 and 9)
Summary
Hydrogen is a clean fuel that produces only water, electricity, and heat when it is consumed in a fuel cell. This fuel has the potential for use in a broad range of applications, across virtually all sectors—transportation, commercial, industrial, residential, and it is portable. Hydrogen and fuel cells can play an important role in decarbonization strategy for a sustainable energy future. The production of hydrogen can be obtained by catalytic steam reforming of hydrocarbons such as methane, naphtha, methanol, ethanol, etc. The MSR catalysts have to be efficient and highly selective toward CO2 over CO, which is important because the CO poisons the anode of the fuel cell [3]
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