Fuel cell power plant

DETAILED DESCRIPTION OF THE INVENTION Referring now to the Figure the fuel cell power plant according to one embodiment of the invention comprises a hydrogen consuming fuel cell 2 with an anode compartment 2a and a cathode compartment 2c held in contact by an electrolyte matrix 2e.
As used herein and discussed above the fuel cell comprises a stack of several individual cells provided with heat exchanging plates (not shown in the Figure) for cooling the stack.
Anode process gas supplied on line 14 is prepared by passing hydrogen and carbon oxide-feed gas in line 4 along with steam supplied on line 6 successively through a methanation unit 9 and a reformer unit 13a.
Before passing the combined stream of feed gas and steam to methanation unit 9 the stream is adjusted to a temperature of about 350.
degree.
C.
by heat exchange with anode exhaust gas 16 in heat exchanger 7 arranged in line 8.
In methanation unit 9 hydrogen and carbon oxides contained in the combined stream of feed gas and steam, are methanated in the presence of a methanation catalyst by the following reactions: CO+3H.
sub.
2 <=>CH.
sub.
4 +H.
sub.
2 O .
DELTA.
H=-206,15 kJ/mole(5) CO.
sub.
2 +4H.
sub.
2 <=>CH.
sub.
4 +2H.
sub.
2 O .
DELTA.
H=-164,96 kJ/mole(6) Waste heat, which is formed during the strongly exothermic methanation reactions (5) and (6), may thereby be used to produce steam.
As mentioned above, methanation unit 9 may comprise an adiabatic methanation reactor and connected thereto a boiling water methanation reactor wherein superheated steam is produced during the methanation process.
The methanated gas leaving methanation unit 9 at a temperature of about 350.
degree.
C.
through line 10, consists mainly of methane, carbon dioxide and steam.
The gas is preheated in heat exchanger 11 to a temperature of about 600.
degree.
C.
with hot exhaust gas in line 16 from anode compartment 2a.
The preheated gas is then passed in line 12 to reformer unit 13a, containing reforming catalyst 13.
The reforming catalyst 13 is in heat conducting relationship with the fuel cell 2 by heat conducting separator plate 15