Development of an Apparatus of Gas Conditioning
Development of a Compact and Economic Apparatus of Gas Conditioning for Proton Exchange Membrane Fuel Cells
Tech Area / Field
- CHE-IND/Industrial Chemistry and Chemical Process Engineering/Chemistry
8 Project completed
Senior Project Manager
Emel'yanov V K
VNIIEF, Russia, N. Novgorod reg., Sarov
- Boreskov Institute of Catalysis, Russia, Novosibirsk reg., Akademgorodok
- Institut für Niedertemperatur-Plasmaphysik, Germany, Greifswald\nMitsubishi Heavy Industries, Ltd., Tokyo / Advanced Technology Research Center, Japan, Yokohama\nAir Products and Chemicals, Inc., USA, PA, Allentown\nUniversité d'Orléans / Groupe de Recherches sur l'Energetique des Milieux Ionises, France, Orleans\nGaz de France, France, Saint Denis La Plaine
Project summaryFuel cells with proton exchange membrane (PEMFC) are being actively developed all over the world for transportation and stationary power plants.
To achieve a wide application of the PEMFC technology it is necessary to develop a compact and economic fuel processor for conversion of the fuel into the hydrogen-containing gas mixture and its conditioning (adjustment to required technical specifications) for the PEMFC application.
The catalytic activity of the current anode PEMFC catalysts is reduced considerably if the gas mixture contains CO amounting from 10 to 100 ppm (depending on the anode catalyst tolerance, which is conditioned by the catalyst composition). At the same time the mixture after passing through he hydrocarbon fuel reformer (steam, air, autothermal) contains a considerable amount of CO (10% and more). Therefore, the hydrogen-containing mixture requires CO removal before its feeding to PEMFC.
The main goal of the current Project is to develop an advanced technology of the hydrogen-containing gas clean-up from CO from 10-15% to 0.001% and manufacture a model of a compact and inexpensive device of gas conditioning to be applied in 5 kW PEMFC.
To meet this goal the works will be conducted in two directions:
– improvement of the CO water-gas shift conversion reactor;
– improvement of the final CO removal reactor while using the catalysts being developed within this Project, to be used for two processes – the preferential CO hydrogenation and the preferential CO oxidation.
Following the traditional scheme, gas conditioning for PEMFC is performed in three stages:
1. The high-temperature CO water-gas shift conversion (600-700 K) at the Fe-Cr catalyst till the residual CO content xCO=2-4%; the volumetric gas rate at the atmosphere pressure is about 400-600 hrs-1.
2. The low-temperature CO water-gas shift conversion (450-500 K) at the Cu-containing catalyst till the residual CO content xCO= 0.5-1.0%; the volumetric gas rate at the atmosphere pressure is about 1000-2000 hrs-1.
3. The preferential (selective) CO oxidation (without H2 oxidation) by the air oxygen till xCO =20-10 ppm.
Within the current Project instead of a traditionally used two-stage CO shift converter (based on high-temperature and low-temperature catalysts) there will be developed a one-stage CO shift converter with the controlled temperature profile of the catalyst bed on the basis of the high-active catalyst being currently developed, which is stable at the wide temperature range. A high heat conductivity of the catalyst will provide the homogeneity of the temperature profile in the radial direction, which meets the requirement of equilibrium degree of CO conversion at the predetermined temperature. A new design of the CO shift converter will have better weight-dimension characteristics compared with those of traditional ones.
Basing on the fundamental studies results on CO hydrogenation and oxidation catalysts, having been obtained at the Boreskov Institute of Catalysis, the Siberian Branch of the Russian Academy of Sciences, within the current Project there will be developed catalysts with a high activity and selectivity, which will provide the level of CO removal from the gas being conditioned up to 20-10 ppm at the final stage.
To meet this Goal the following works will be fulfilled while development of an advanced technology of gas conditioning:
– A highly active catalyst for the WGS reaction with the improved heat-conducting properties, which is stable at 530-630 K, will be used. Application of such a catalyst in the apparatus with a single-bed catalyst (the adiabatic heating is 80-100 °C) will provide the CO concentration not more than 1%vol. (preferably – 0.5%vol.). The minimal operating GSV at the atmosphere pressure will be 3500-5000 hr-1.
– An original design of the catalytic reactor will be applied. The controlled temperature profile along the catalyst bed should be maintained continuously. A high temperature of the first part of the reactor and the lowest possible temperature (530 K) at the reactor outlet will provide a high performance per unit of volume of the reactor and a deep CO conversion.
– A fine removal of CO admixtures should be performed either by selective CO hydrogenation or by selective CO oxidation, preferably in two stages, combining both processes. The search of the most effective catalysts and optimal operating conditions will be provided. The minimal operating rate of gas flow at the atmosphere pressure while the final removal will be 5000 hr-1.
As a result of the Project implementation there will be developed catalysts of: (1) CO shift conversion using water steam, which is stable in a wide temperature range with the improved thermotechnical characteristics; (2) preferable (selective) CO hydrogenation and (3) preferable CO oxidation. A model apparatus of gas clean-up will be developed and manufactured for 5 kW PEMFC power plants. Scientific goals will be met while development of compact and economic fuel processors for PEMFC-based power plants.
The results of works can be applied while development of PEMFC power plants with the power range of 5 kW and higher. It is proposed to improve weight and dimension characteristics and reduce the cost of the apparatus for the fuel gas clean-up from CO by 3-5 times as compared with clean-up devices developed using traditional principles and catalysts.
Results of these works will be valuable from scientific and practical points of view as the cost reduction of PEMFC power plants will be a significant step towards their commercialization; the Project implementation will allow to increase the effectiveness of fossil fuel consumption and reduce a harmful impact on the environment.
The Project will be fulfilled by a team of highly qualified specialists, the major part is involved into weapons programs. The executors of works have experience in the development of fuel processors and catalysts for the above-mentioned processes as well as in the development of fuel cell power plants. Their qualification is confirmed by the experience, having been accumulated in the development of catalysts of water-gas shift reaction (2 patents, 1 catalyst has been successfully applied on the industrial scale), CO removal (1 patent, 1 catalyst has been successfully applied in industry), the Fischer-Tropsch synthesis (1 patent) as well as in the development of compact catalytic apparatuses (3 patents, ISTC Project #763). During last 5 years the research team successfully implemented the following international projects: NWO 047.005.03.96; ISTC N 763. At present the team is performing the research work in the frame of the following projects: NATO SfP-972557; Copernicus 2 ISA-2-1999-10040.
Technical issues on the Project will be constantly discussed with collaborators. Joint experiments and developments can be conducted.
The proposed Project meets the ISTC goals and objectives and enables to support applied research in the area of fuel cell power plants development, which are promising units for conversion of the chemical energy of hydrocarbon fuel into electric and heat power, which may be applied worldwide and which meet environmental requirements.
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