Gasaufbereitung für Brennstoffzellen

Peters, Ralf; Meißner, J.

doi:10.1002/cite.200407006

“…reformer, desulfurization unit, WGS reactor, PROX reactor and catalytic burner, heat exchanger, evaporators, compressor, pumps and finally electronics and insulation [244]. Present data show a power density of 1.8 kW e L −1 for a 5-kW e autothermal diesel reformer with integrated heat exchangers [163]. By integration measures, all the required heat exchangers, i.e.…”

Section: Catalytic Combustion Of Fuel Cell Tail Gasesmentioning

confidence: 96%

“…HTS, high-temperature shift; LTS, low-temperature shift; HTS&LTS: X CO, NTS, in = 3.5%, X-axis shows T NTS , GHSV values in L h −1[163]. HTS, high-temperature shift; LTS, low-temperature shift; HTS&LTS: X CO, NTS, in = 3.5%, X-axis shows T NTS , GHSV values in L h −1[163].…”

mentioning

confidence: 99%

Fuel Processors

Peters

¹

2008

Handbook of Heterogeneous Catalysis

4

0

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The sections in this article are Introduction Energy Carriers for Fuel Cells Thermodynamic Calculations Reforming Processes for Hydrogen Production Thermodynamic Equilibrium Calculations Carbon Formation and Deposition Fuel Pre‐Processing Removal of Harmful Species from Methanol and Water Desulfurization Evaporation of Liquid Fuels Methanol Steam Reforming Catalysts for Methanol Steam Reforming Reaction Path of Methanol Steam Reforming on Cu / Zn O Catalysts Active Sites of Cu / Zn O Catalysts Pd / Zn O Catalysts Kinetics of Methanol Steam Reforming Reformer Design Based on Laboratory‐Scale Experiments Example of Methanol Steam Reformer Development Autothermal Reforming of Gasoline and Diesel Internal Steam Reforming of Methane for SOFC Systems Gas Treatment for PEFC Systems Water‐Gas Shift Reaction CO Fine Cleaning A H 2 Separation Membranes B Preferential CO Oxidation C Selective CO Methanation Catalytic Combustion of Fuel Cell Tail Gases Component and System Design Heat Exchanger Networks Innovative Reactor Concepts Dynamic System Modeling Outlook Acknowledgments

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“…Unfortunately, even traces of CO deactivate the anode electro-catalyst of the PEMFC. Therefore, the CO content must not exceed 10 ppm for Pt-anodes and 100 ppm for PtRu-anodes [4,5]. Hence, the CO content in the operating gas has to be further reduced below these threshold values, preventing a degradation of the fuel cell catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…CO preferential oxidation (CO-PROX) has so far been a reliable technique as a fine purification step of the feed gas downstream the WGS unit [2,[6][7][8][9][10]. In order to achieve the required low CO concentration permanently, a two-step system is usually needed [4]. In addition, this process requires an additional, closely controlled, low rate O 2 supply to keep the unwanted oxidation of hydrogen as low as possible [2,10].…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Reactor Design Aspects of Selective Methanation of CO over a Ru/γ-Al2O3 Catalyst in CO2/H2 Rich Gases

Garbis

¹

,

Kern

²

,

Jess

³

2019

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Polymer electrolyte membrane fuel cells (PEMFCs) for household applications utilize H2 produced from natural gas via steam reforming followed by a water gas shift (WGS) unit. The H2-rich gas contains CO2 and small amounts of CO, which is a poison for PEMFCs. Today, CO is mostly converted by addition of O2 and preferential oxidation, but H2 is then also partly oxidized. An alternative is selective CO methanation, studied in this work. CO2 methanation is then a highly unwanted reaction, consuming additional H2. The kinetics of CO methanation in CO2/H2 rich gases were studied with a home-made Ru catalyst in a fixed bed reactor at 1 bar and 160–240 °C. Both CO and CO2 methanation can be well described by a Langmuir Hinshelwood approach. The rate of CO2 methanation is slow compared to CO. CO2 is directly converted to methane, i.e., the indirect route via reverse water gas shift (WGS) and subsequent CO methanation could be excluded by the experimental data and in combination with kinetic considerations. Pore diffusion may affect the CO conversion (>200 °C). The kinetic equations were applied to model an adiabatic fixed bed methanation reactor of a fuel cell appliance.

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“…This means to couple the gas process and the fuel cell step thermally. Most frequently publications on gas process technology of fuel cell systems deal with catalysts, Peters [1], and much less on the thermodynamics of the process. In the Handbook of Fuel Cells [2] electrical efficiencies of fuel cells are dealt with but that of methane fired fuel cell power plants are not treated.…”

Section: Introductionmentioning

confidence: 99%

Electrical efficiencies of methane fired, high- and low- temperature fuel cell power plants

Wendt

¹

2005

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The important system difference between power plants based on low temperature and high temperature fuel cells is that gas reforming and shift conversion is thermally decoupled from the cell in low temperature cell power plants whereas the gas process steps are performed at close to the elevated fuel cell temperatures in high temperature fuel cell power plants. This article elucidates the consequences: assuming equal electrical efficiencies for the respective cells (50%) it is shown that thermal decoupling leads to energy and exergy losses and sizably lower electrical system efficiencies because heat for the generation of the process steam necessitates the combustion of methane. Also hydrogen losses in the step for preferential oxidation of carbon monoxide (Selox process) and several heat transfer steps add to the lower efficiency of low temperature systems. Low temperature fuel cell power plants need 15-17% more fuel than high temperature fuel cell power plants for the same amount of electric energy. The theoretical comparison of an adiabatic LT and HT fuel cell process reveals that, with postulated electrical cell efficiencies of 50%, the theoretical electrical efficiency of the LT process is 6-7% points lower than that for the HT-process (35 vs. 41%). For exergy efficiencies also taking into account rejected heats, the numbers read 43 and 58%.

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Gasaufbereitung für Brennstoffzellen

Cited by 8 publications

References 4 publications

Fuel Processors

Fuel Processors

Kinetics and Reactor Design Aspects of Selective Methanation of CO over a Ru/γ-Al2O3 Catalyst in CO2/H2 Rich Gases

Electrical efficiencies of methane fired, high- and low- temperature fuel cell power plants

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