Mass transfer composite membrane for a fuel cell power plant

Abstract

A mass transfer composite membrane for use with a fuel cell power plant includes a transfer medium core between opposed, rigid, porous support sheets. An inlet surface of the composite membrane is positioned in contact with an oxidant inlet stream of a fuel cell power plant, and an opposed exhaust surface of the composite membrane is positioned in contact with an exhaust stream exiting the fuel cell power plant to recover mass such as water from the exhaust stream and transfer it into the oxidant inlet stream entering the fuel cell. The transfer medium core may comprise any of a variety of materials for sorbing a fluid substance consisting of polar molecules such as water molecules from a fluid stream consisting of polar and non-polar molecules. A preferred transfer medium core is an ionomeric membrane such as a water saturated polyfluorosulfonic acid ionomer membrane. The porous support sheets may comprise a reinforcing fiber with a thermoset resin, such as a carbon sheet with a phenolic resin, or a glass fiber with an epoxy resin, wherein the sheets are thermoset into a rigid configuration. The mass transfer composite membrane may be a flat or a mounded layer defining protrusions and depressions. A plurality of the mounded layer membranes may be disposed within a frame in mirror-image association wherein protrusions and depressions formed by the mounds of adjacent membranes contact each other to define serpentine passages for the inlet and exhaust streams.