Fuel cell system with fuel distillation unit

A fuel cell system comprising:

• a fuel cell stack;
• a first distillation unit configured to receive a fuel source, wherein the fuel cell stack provides heat to the first distillation unit using at least one exhaust stream of the fuel cell stack and
• a controller programmed to:
• control a temperature in the first distillation unit to produce a distillate vapor from the fuel source having remaining water vapor and a ratio of fuel to water vapor;
• determine when the ratio of fuel to water vapor allows the vapor to be directly reformed using steam reformation;
• provide the distillate vapor containing the remaining water vapor from the first distillation unit to the fuel cell stack during fuel cell system operation when the ratio of fuel to water vapor as determined by the controller allows the vapor to be directly reformed steam reformation;
• and
• provide the distillate vapor containing the remaining water vapor from the first distillation unit for additional distillation when the ratio of fuel to water vapor as determined by the controller does not allow the vapor to be directly reformed using steam reformation, wherein the additional distillation is conducted in a second distillation unit that uses a process that differs from a process used by the first distillation unit.