Patent ID: 7261150

Claim:
An apparatus for humidifying first and second process gas streams, for a fuel cell, the apparatus comprising: a steam supply line; a first humidification unit having an inlet for the first process gas stream and a first steam supply means connected to the steam supply line, for supplying steam into the first process gas stream, to add humidity to the first process gas stream at a first temperature, to a humidity in excess of a required humidity level; a first heat exchanger connected to the first humidification unit, for cooling the first process gas stream to a second, lower temperature, whereby excess moisture in the first process gas stream condenses; a separator connected to the first heat exchanger, for removing the condensed moisture, whereby the first process gas stream leaving the separator has a known temperature and a known humidity level; a first heater connected to the separator, for heating the first process gas stream to a third temperature, greater than the second temperature, whereby the process gas stream has a known absolute humidity level; a second humidification unit including an inlet for the second process gas stream and a second steam supply means connected to the steam supply line, for supplying steam into the second process gas stream, to add humidity to the second process gas stream at a fourth temperature, to a humidity in excess of a required humidity level; a second heat exchanger connected to the humidification unit, for cooling the second process gas stream to a fifth, lower temperature, whereby excess moisture in the second process gas stream condenses; a second separator connected to the second heat exchanger, for removing the condensed moisture, whereby the second process gas stream leaving the second separator has a known temperature and a known humidity level; a second heater connected to the second separator, for heating the second process gas stream to a sixth temperature, greater than the fifth temperature, whereby the second process gas stream has a known absolute humidity level; wherein the first heater comprises a third heat exchanger and, wherein each of the first and third heat exchangers is provided with a corresponding first temperature control circuit for controlling the temperature of the corresponding heat exchanger and including a conduit for a fluid, a pump for pumping the fluid and a first cooling means having connections for a first coolant supply, with a first common coolant supply being connected to both of the first cooling means.