Compact Natural Gas Steam Reformer
Development of a Compact Unit for Steam Natural Gas Reforming Conjugated by Heat with Oxidation of Waste Anode Gas of Fuel Cells
Tech Area / Field
- NNE-FCN/Fuel Conversion/Non-Nuclear Energy
- NNE-EPP/Electric Power Production/Non-Nuclear Energy
8 Project completed
Senior Project Manager
Emel'yanov V K
VNIIEF, Russia, N. Novgorod reg., Sarov
- Boreskov Institute of Catalysis, Russia, Novosibirsk reg., Akademgorodok
- Consiglio Nazionale delle Ricerche / Istituto di Ricerche sui Metodi e Processi Chimici per la Trasformazione e l'Accumulo dell'Energia, Italy, Messina\nRobert Bosch GmbH, Germany, Stuttgart\nUniversität Stuttgart / Institut fur Chemische Verfahrenstechnik, Germany, Stuttgart\nMitsubishi Heavy Industries, Ltd., Tokyo / Advanced Technology Research Center, Japan, Yokohama
Project summaryThe main objective of the Project is the development of a demonstration sample of the compact natural gas steam reformer with the hydrogen yield corresponding to electric power of 12kW per 1 liter of the reformer volume for 5kW power plant based on solid polymer fuel cells.
The well-recognized leader among devices for direct conversion of the chemical energy of hydrocarbon fuels into electric and heat power is the fuel cell (FC). At the present time a high cost of fuel cell-based power plants (PP) is the main factor that impedes their wide application in industry. The conciderable part of the FC based PP cost is made up by the fuel processor, which is a device for conversion of hydrocarbon fuels into the hydrogen-containing mixture, applicable for the FC stack. The core of the fuel processor is a reformer, and, therefore, a significant reduction of its cost and improvement of its performance coould provide conciderable contribution to reducction of the cost of FC power plants.
The cost of the reformer can be significantly reduced at the expense of:
· Application of new principles of the process organization that leads to increase of hydrogen yield per unit of volume of the reformer;
· Application of new inexpensive catalysts;
· Reduction of the reformer weight.
Within this Project it is proposed to use a new technical approach of the process organization and design of the natural gas reformer that will allow to increase significantly its specific output as compared with conventional natural gas steam reformers where the granular catalyst is used. This approach is based on conjugation by heat of the endothermic reaction of methane steam conversion and the exothermal reaction of waste anode gas oxidation. The approach being developed is based on the following methodological principles:
· There is no spatial separation between the heat- generating and heat-absorbing surfaces;
· The catalyst is a component of the unit design;
· Together with the required activity the catalyst should provide thermal and physical properties comparable with the other reformer materials properties.
In order to bring these principles into effect it is necessary to develop inexpensive metal porous highly heat-conducting catalysts for natural gas steam conversion and waste anode gas oxidation. These catalysts are sintered with different sides of the metal wall, separating the zones where the endothermic hydrocarbon conversion and exothermal anode gas oxidation take place. A high thermal conductivity of the both catalyst and the wall, absence of spatial separation between the reaction zones provide the required heat conjugation of the steam conversion and the waste anode gas oxidation reactions without mixing of the reaction products and dilution with the inert air nitrogen. All these enable to develop a unit, which possesses the advantages both of existing steam reformers (with a high hydrogen yield) and of autothermal systems (a small weight and dimensions, a low hydraulic resistance, and an insignificant response time). Such a method of heat conjugation of the reactions of steam reforming and methane oxidation was implemented at the BG Compact Reformer. In laboratory conditions this reformer showed the hydrogen yield that corresponds to the power of 12 kW per one liter of the reformer volume compared to that of 0.03 kW/l provided by conventional reformers.
The principle of heat conjugation was also applied in apparatuses based on catalytic heat exchangers, being developed at the Institute of Catalysis. It was proved that the output per unit of the reactor volume can be increased by a factor of 100. We verified these principles while development of catalytic water heating systems and compact heat sources for residential use.
In contrast to the BG Compact Reformer, where thin-film catalysts with thickness of 10-50mkm were used, in the suggested reformer there will be used metal porous supports with thickness of several mm, which will be sintered with the metal surface. This provides a possibility for further increase of the specific output and enables to develop a compact unit of natural gas steam conversion with the hydrogen yield providing not less than 12 kW electric power per 1 liter of the reformer volume.
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