The Operation of Polymer Electrolyte Membrane Fuel Cell using Hydrogen Produced from the Combined Methanol Reforming Process (original) (raw)
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Hydrogen, Fuel Cell & Energy Storage, 2017
There are several obstacles to the commercialization of PEM fuel cells. One of the reasons is that the presence of carbon monoxide (CO) in the reformatted fuel, even at a very small scale, decreases the fuel cell performance. The aim of this paper is to investigate the effect of CO in reformatted fuel on PEM fuel cell performance. For this purpose, a steady state, one-dimensional and non-isothermal model is utilized to evaluate the PEM fuel cell performance with and without CO in the fuel stream. The governing equations which includes the conservation of mass, energy and species equations are solved in MATLAB software and validated by the available data in the literatures. The results indicate that when pure hydrogen is used as anode fuel the activation loss of the cathode is very large relative to the anode value; also, the maximum temperature occurs in the cathode catalyst layer. When reformatted fuel is applied as anode gas stream, activation loss and anode temperature increase by increasing the CO concentration in the reformatted fuel. As example, when CO concentration is over 50 ppm in the fuel stream, the activation loss and anode will be higher than the relevant amounts in cathode catalyst layer. Also it is observed that by increasing the fuel cell temperature and anode pressure, the CO effects on fuel cell performance are reduced.
Performance and endurance of a high temperature PEM fuel cell operated on methanol reformate
International Journal of Hydrogen Energy, 2014
This paper analyzes the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC) at varying temperatures, ranging from 140 C to 180 C. For the study, a H 3 PO 4 e doped polybenzimidazole (PBI) e based membrane electrode assembly (MEA) of 45 cm 2 active surface area from BASF was employed. The study showed overall negligible effects of methanol-water vapor mixture slips on performance, even at relatively low simulated steam methanol reforming conversion of 90%, which corresponds to 3% methanol vapor by volume in the anode gas feed. Temperature on the other hand has significant impact on the performance of an HT-PEMFC. To assess the effects of methanol-water vapor mixture alone, CO 2 and CO are not considered in these tests. The analysis is based on polarization curves and impedance spectra registered for all the test points. After the performance tests, endurance test was performed for 100 h at 90% methanol conversion and an overall degradation rate of À55 mV/ h was recorded.
JSAE Review, 2002
The fuel cell is an environmentally-friendly power source due to high efficiency and cleanness. Considering safety, tractability and infrastructure, a methanol reformer is a candidate for the supply of hydrogen to fuel cell vehicles. However as CO generated by methanol reformers poisons the platinum catalysts of anodes, the operating conditions were studied in order to minimize the CO emissions from the reforming system. This study tested a methanol reforming system including a steam reformer and preferential oxidizer, established the chemical reaction rates of reforming and CO oxidation and calculated the dynamic changes in CO concentration from the reformer using a newly developed simulator.
Chinese Journal of Chemical Engineering, 2006
Autothermal reforming (ATR) is one of the leading methods for hydrogen production from hydrocarbons. Liquefied petroleum gas, with propane as the main component, is a promising fuel for on-board hydrogen producing systems in fuel cell vehicles and for domestic fuel cell power generation devices. In this article, propane ATR process is studied and operation conditions are optimized with PRO/ 11 @ from SIMSCI for proton exchange membrane fuel cell application. In the ATR system including water gas shift and preferential oxidation, heat in the hot streams and cold streams is controlled to be in balance. Different operation conditions are studied and drawn in contour plots. The region for ATR reforming with the highest efficiency can thus be identified. One operation point was chosen with the following process parameters: feed temperature for the ATR reactor is 425"C, steam to carbon ratio S/C is 2.08, air stoichiometry is 0.256. Thermal efficiency for the integrated system is calculated to be as high as 84.0 % with 38.27 % H2 and 3.2pl.L-' CO in the product gas.
Components for PEM fuel cell systems using hydrogen and CO containing fuels
Electrochimica Acta, 1998
ÐProton exchange membrane fuel cells (PEMFC) show a signi®cant performance drop in CO containing hydrogen as fuel gas in comparison to pure hydrogen. The lower performance is due to CO adsorption at the anode thus poisoning the hydrogen oxidation reaction. Two approaches to improve the cell performance are discussed. First, the use of improved electrocatalysts for the anode, such as PtRu alloys, can signi®cantly enhance the CO tolerance. On the other hand, CO poisoning of the anode could be avoided by the use of non-electrochemical methods. For example, the addition of liquid hydrogen peroxide to the humidi®cation water of the cell leads to the formation of active oxygen by decomposition of H 2 O 2 and the oxidation of CO. In such a way a complete recovery of the CO free cell performance is achieved for H 2 /100 ppm CO.
Chinese Journal of …, 2006
Autothermal reforming (ATR) is one of the leading methods for hydrogen production from hydrocarbons. Liquefied petroleum gas, with propane as the main component, is a promising fuel for on-board hydrogen producing systems in fuel cell vehicles and for domestic fuel cell power generation devices. In this article, propane ATR process is studied and operation conditions are optimized with PRO/ 11 @ from SIMSCI for proton exchange membrane fuel cell application. In the ATR system including water gas shift and preferential oxidation, heat in the hot streams and cold streams is controlled to be in balance. Different operation conditions are studied and drawn in contour plots. The region for ATR reforming with the highest efficiency can thus be identified. One operation point was chosen with the following process parameters: feed temperature for the ATR reactor is 425"C, steam to carbon ratio S/C is 2.08, air stoichiometry is 0.256. Thermal efficiency for the integrated system is calculated to be as high as 84.0 % with 38.27 % H2 and 3.2pl.L-' CO in the product gas.
High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have received substantial attention in stationary sector applications, due to their high carbon monoxide (CO) tolerance, high-quality waste heat and simplified water management system. Hydrogen rich gas produced in a fuel reforming process can be used and can be directly supplied to the HT-PEMFC stack anode omitting complex hydrogen purification process. It allows a wide range of fuel flexibility for the reforming process. The present study is an analysis of HT-PEMFC stack performance operating with an integrated steam reformer, operated with various fuels like ethanol, glycerol, methanol, methane and other fuels. The HT-PEMFC stack is modelled with a concept of varying local current density in the cathode catalyst layer.
A concept of compact, heat integrated system of PEMFC stack and methanol steam reformer (MSR) is proposed. Three separate systems are designed based on different types of PEMFC stacks. Proposed novel HT PEMFC (nHT PEMFC) stack operates at 255 C which matches the MSR operating at 250 C. Systems are compared using mass and energy balances model coupled to a physical model. Highest efficiency is attained by the system with nHT PEMFC stack operating at 255 C. a b s t r a c t Efficiently combining proton exchange membrane fuel cell (PEMFC) stack with methanol steam reformer (MSR) into a small portable system is still quite a topical issue. Using methanol as a fuel in PEMFC stack includes a series of chemical processes where each proceeds at a unique temperature. In a combined MSRePEMFC-stack system with integrated auxiliary fuel processors (vaporizer, catalytic combustor, etc.) the processes are both endothermic and exothermic hence their proper thermal integration can help raising the system efficiency. A concept of such fully integrated and compact system is proposed in this study. Three separate systems are designed based on different PEMFC stacks and MSR. Low-temperature (LT) and conventional high-temperature (cHT) PEMFC stack characteristics are based on available data from suppliers. Also, a novel high-temperature (nHT) PEMFC stack is proposed because its operating temperature coincides with that of MSR. A comparative study of modelled systems is performed using a mass and energy balances zero-dimensional model, which is interdependently coupled to a physical model based on finite element method (FEM). The results indicate that a system with nHT PEMFC stack is feasible and has the potential to reach higher system efficiencies than systems with LT or cHT PEMFC stacks.