Gas distribution in molten-carbonate fuel cells

This paper presents an investigation of the gas distribution in a large-scale stack such as a 200-kW internal reforming (IR) molten-carbonate fuel cell (MCFC) stack. The gas flow scheme is important for the performance of the cell and for the temperature distribution. In order to supply gas to each cell uniformly and to achieve a reasonable temperature distribution, we have proposed a large-scale stack divided into four blocks from the point of view of the gas flow scheme. In our proposal, each block consists of 55 cells, 9 internal reforming units, and 1 internal manifold. The flow variation was examined by measurements on an element, numerical analysis, and measurements on a stack. We have found that (i) the flow variation among the four blocks is 1.5% or less and can be made better by using an orifice plate; (ii) the flow variation along the stacking direction in each block is within ±1%; (iii) improvement of the flow distribution in the reforming unit affects the uniformity of the temperature distribution in the cell area. These results can improve the prospects for 200 kW stacks.