Experimental Evaluation of CO Poisoning of an Air-Breathing High Temperature PEM Fuel Cell Stack

Abstract

In this paper, we experimentally studied an air breathing high temperature PEM fuel cell at steady operating conditions to investigate the effects of CO poisoning at different temperatures ranges between 120°C∼180°C. The effects of changes in temperatures with different amount of CO poisoning on the current-voltage characteristics of the fuel cell are investigated. Experimental data of this type would be very useful to develop design parameters of fuel processor based on reformate hydrocarbons. The high CO tolerance of high temperature PEM fuel cells makes it possible to use the reformate gas directly from the reformer without further CO removal. Here we considered the fact that a steam reformer is a consumer of heat and water, and fuel cell stacks are a producer of heat and water. Thus, integration of the fuel cell stack and the reformer is expected to improve the system performance. The results obtained from the experiments showed variations in current-voltage characteristics at different temperatures with different CO poisoning rates. The results will help to understand the overall system performance development strategy of high temperature PEM fuel cell in terms of current-voltage characteristics, when fed with on-site reformate hydrogen gas with variable CO concentrations.

Experimental performance evaluation of a combustion heat-assisted catalytic flat plate fuel reformer for fuel cell grade hydrogen

“…While using optimized reformer geometry, at the end of initial reforming process (i.e. before WGS reaction start) we observed that the reformate gas temperature was at Channel length (m) 18 reformate gases need to have temperature at around 800 o K at the end of initial fuel reforming process. In order to comply with these requirements, we used a heat exchanger to bring down the reformate gas temperature from 1115 o K to 800 o K before it entering into the water gas shift reaction zone of the reformer.…”

“…It is due to the fact that platinum (Pt) catalyst is used in the PEM fuel cell for electro-kinetic reactions to produce useful electric power. CO poison Pt catalyst as per the thermo-absorption and chemisorption properties of Pt [18]. So, it is necessary to make sure that the reformate gas contains very low level of CO in order to avoid Pt poisoning during HTPEMFC stack operation with reformate gas.…”

“…The only issue of using reformate fuel into the PEMFC stack is to degradation of PEMFC stack performance due to poisoning of Pt catalyst, used in PEMFC, by the carbon 4 monoxide (CO) presence in the reformate fuel [1][2]. Recently, development of temperature resistant high conductive polymer membranes, such as the acid-doped polybenzimidazole (PBI) membranes [2,[18][19][20], open up the opportunity to build high temperature PEM fuel cell (HTPEMFC) stack which can be fed with lower quality (i.e. higher CO concentrations in hydrogen) reformate hydrogen [2,[18][19][20] directly from the fuel reformer.…”

“…Recently, development of temperature resistant high conductive polymer membranes, such as the acid-doped polybenzimidazole (PBI) membranes [2,[18][19][20], open up the opportunity to build high temperature PEM fuel cell (HTPEMFC) stack which can be fed with lower quality (i.e. higher CO concentrations in hydrogen) reformate hydrogen [2,[18][19][20] directly from the fuel reformer. From the thermodynamics point of view, the high operational temperature makes it possible to improve the CO tolerance in HTPEMFC stack at a higher level [2,[18][19][20].…”

“…higher CO concentrations in hydrogen) reformate hydrogen [2,[18][19][20] directly from the fuel reformer. From the thermodynamics point of view, the high operational temperature makes it possible to improve the CO tolerance in HTPEMFC stack at a higher level [2,[18][19][20]. Hydrogen-rich reformate can be produced on-board by reforming process using hydrocarbon fuels available at the nationwide refueling stations [5][6][21][22][23][24][25][26][27][28][29].…”