NOVELTY - Because the mass transfers directly from the cathode and anode exhausts (40, 48) into the process oxidant stream the rate of uptake of mass and therefore heat by the oxidant stream is not solely a function of the ambient air temperature or humidity, but is a function of partial pressure differences between mass in the oxidant stream entering the plant and the mass in the plant exhaust stream. This allows for more water recovery than in conventional plant using an ambient air cooled condensing heat exchanger (94).    USE - Fuel cell power plants.    ADVANTAGE - The system is self sufficient in water over a broad range of conditions and has improved energy efficiency.    DETAILED DESCRIPTION - Mass and heat recovery system for a fuel cell power plant that generates electricity from a reducing and oxidant fluid comprising; (a) At least one fuel cell (12) for fluid. (b) Fuel processing means for processing hydrocarbon into a reducing fluid including an auxiliary burner that receives and burns an anode exhaust stream from the fuel cell and directs the anode exhaust stream into a plant exhaust stream. (c) Primary exhaust passage that passes a process oxidant stream from a supply into the fuel cell. (d) Cathode exhaust passage that passes cathode exhaust out of the fuel cell into the plant exhaust where it mixes with the burned anode exhaust. (e) Direct mass and heat transfer device in fluid communication with the primary oxidant passage and with the plant exhaust passage including; (i) transfer medium means for sorbing a fluid substance consisting of polar molecules within the plant exhaust stream and for desorbing the molecules into the oxidant stream, (ii) separator housing means for supporting the transfer medium in mass transfer relationship with the plant exhaust stream and process exhaust stream so that both streams contact the mass transfer medium, and for preventing bulk mixing of the plant exhaust and process oxidant streams.    DESCRIPTION OF DRAWING(S) - The drawing shows a mass and heat recovery system for a fuel cell power plant    Fuel cell (12)    Heat transfer device (14)    Electrolyte (16)    First electrolyte surface (18)    Second surface (20)    Anode electrode (22)    Anode support (24)    Cathode electrode (26)    Cathode support (28)    Frame (30)    Electricity use (32)    External load circuit (34)    Oxidant source (36)    Oxidant passage (38)    Cathode exhaust (40)    Plant exhaust (42)    Reducing fluid inlet (44)    Burner (46)    Anode exhaust (48)    Steam generator (50)    Heat conduit (52)    Reformer (54)    Carbon fuel supply (58)    Fuel line (60)    Reformed fuel discharge (62)    Burner exhaust (64)    Water shift reactor (66)    Line (67)    Selective oxidizer (68)    Transfer medium (72)    Separator housing (74)    Inlet chamber (76)    Exhaust chamber (78)    Oxidant feed (80)    Plant discharge vent (82)    Blower (84)    Secondary oxidant passage (86)    Tertiary oxidant passage (88)    Fine pore water plate (90)    Coolant water (92)    Heat exchanger (94)