Fuel cell system

A process for producing electricity in a fuel cell which comprises:

• a) pre-reforming a higher carbon (C2+) hydrocarbon fuel in a pre-reformer at a temperature of at least 300° C. under conditions effective to achieve substantially complete conversion of higher carbon (C2+) hydrocarbons to produce a pre-reformed fuel stream containing methane, hydrogen and oxides of carbon;
• b) subsequently subjecting the pre-reformed fuel stream obtained in a) to methanation at a temperature in the range of 250° C. to 450° C. and which is less than the pre-reforming temperature under conditions effective to produce a fuel stream having an increased concentration of methane relative to the pre-reformed fuel stream;
• and
• c) supplying the fuel stream and an oxidant to a high temperature fuel cell in which methane is reformed and electricity is produced by reacting the fuel stream at an anode of the fuel cell and reacting the oxidant at a cathode of the fuel cell,
• wherein the methane content of the fuel stream resulting from methanation is at least 40% by volume (measured on a dry basis).