(JP2513800-B2)      A heat exchanger assembly for use in controlling fluid temps. in a fuel cell power plant, and a method of operating the heat exchanger are claimed.    The heat exchanger comprises a single housing through which reformed fuel from a reformer is passed from the housing inlet to the outlet in heat exchange relationship with (i) raw hydrocarbon fuel which is passed from the outlet to the inlet, (ii) coolant water,, from a power section of the power plant, which is passed from the outlet to a middle portion of the housing and (iii) steam from the power plant which is passed from the middle portion to the inlet, such that (a) the reformed fuel enters at reformer temps. and exits at power point power section temps., (b) raw hydrocarbon fuel enters at ambient temp. and exits at reformer temps., (c) coolant water enters at power station temps. and exits as a two phase water-steam mixt. and (d) steam enters at steam separator temps. and exits at reformer temps.    ADVANTAGE -   A single heat exchanger is used for cooling the reformer effluent fuel gas to temps. suitable for the shift converter operation which precedes fuel gas transfer to the stack, producing some of the steam used in the reformer, superheating the steam and preheating the raw hydrocarbon fuel prior to reforming. The heat exchanger is brought to operating temp. on start-up by coolant from the stack and by purging steam, thus avoiding the need for separate electric start-up heaters.    (JP1070644-A)      A heat exchanger assembly for use in controlling fluid temps. in a fuel cell power plant, and a method of operating the heat exchanger are claimed.    The heat exchanger comprises a single housing through which reformed fuel from a reformer is passed from the housing inlet to the outlet in heat exchange relationship with (i) raw hydrocarbon fuel which is passed from the outlet to the inlet, (ii) coolant water,, from a power section of the power plant, which is passed from the outlet to a middle portion of the housing and (iii) steam from the power plant which is passed from the middle portion to the inlet, such that (a) the reformed fuel enters at reformer temps. and exits at power point power section temps., (b) raw hydrocarbon fuel enters at ambient temp. and exits at reformer temps., (c) coolant water enters at power station temps. and exits as a two phase water-steam mixt. and (d) steam enters at steam separator temps. and exits at reformer temps.    ADVANTAGE -   A single heat exchanger is used for cooling the reformer effluent fuel gas to temps. suitable for the shift converter operation which precedes fuel gas transfer to the stack, producing some of the steam used in the reformer, superheating the steam and preheating the raw hydrocarbon fuel prior to reforming. The heat exchanger is brought to operating temp. on start-up by coolant from the stack and by purging steam, thus avoiding the need for separate electric start-up heaters.