Accumulation and continuous removal of impurities in fuel cells: I. One-dimensional model
Abstract
A mode of operation and a design technique have been developed which permit the attainment of continuous purging of impurities directly from the gas compartments of a fuel cell—either anode, cathode, or both—with the realization of minimum reactant loss, most stable voltage and current output, and operating conditions with respect to reactant gas flow and electrolyte inventory. We have found a way to eliminate the complex periodic purge valves and attendant electronics by a fuel cell system which is both simple in structure and operation and which has a high degree of reliability. The technique was suggested by the observation that in dead-ended fuel cell gas compartments, the inert impurities present in reactant gases tend to accumulate at the dead-ended portion of the cell. Hence a small amount of bleed should be placed there. This observation has been made analytically by solving numerically a system of two partial differential equations simultaneously.