Patent ID: 6887602
Filing Date: 2005-05-03
Classification: H01M,Y02E

Abstract:
1. In a fuel cell system comprising a fuel cell that consumes hydrogen in the electrochemical production of electricity, a fuel processor for producing said hydrogen from a hydrogen-containing fuel and steam, and a steam vaporizer for converting water into said steam and supplying a first quantity of said steam to said fuel processor at a first pressure, wherein the improvement comprises a steam buffer communicating with said fuel processor in parallel with said steam vaporizer for supplying a second quantity of steam to said fuel processor during surges in the electrical power demanded from said fuel cell system, said steam buffer comprising a vessel containing a pool consisting essentially of water under a second pressure greater than said first pressure and at a temperature greater than the boiling point of water at said first pressure, a pump for supplying water to said vessel at said second pressure, a heat exchanger for heating said water to said temperature, an inlet valve communicating said pump with said vessel, an outlet valve communicating said vessel with said fuel processor, and a controller for closing said inlet valve and opening said outlet valve during said surges to rapidly reduce the pressure in said vessel so as to cause said water in said pool to flash vaporize and provide said second quantity.