JP2003051326A - Fuel cell power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generation system composed by enhancing power generation efficiency of an electrolyte type fuel cell. SOLUTION: This fuel cell power generation system is provided with, a reformer 7 for generating a reformed gas G from a fuel gas X, an electrolyte type fuel cell 1 composed by catching an electrolyte film between a pair of electrodes comprising a fuel electrode 3 and an oxidizer electrode 2 for generating power by using the reformed gas G fed to the fuel cell 3 and an oxidizer gas A fed to the oxidizer electrode 2, a heat exchanger 13 disposed in a reformed feeding passage 6 for feeding the reformed gas G to the fuel electrode 3 of the fuel cell 1 from the reformer 7 and used for cooling the reformed gas G, and a trap 15 disposed on the reformed gas outlet 14 side of the heat exchanger 13 for draining condensed water D from the reformed gas G flow.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment and countermeasure for condensed water generated in a fuel cell power generation system including a reformer and an electrolyte fuel cell. Related to the fuel cell power generation system performed. 2. Description of the Related Art A conventional fuel cell power generation system is disclosed, for example, in Japanese Patent Application Laid-Open No. 2001-155748. FIG. 4 shows the fuel cell power generation system disclosed herein. The solid polymer electrolyte fuel cell 1 includes an oxidizer electrode 2 and a fuel electrode 3 with a solid polymer electrolyte membrane interposed therebetween. Oxidizer electrode 2
For example, air is supplied as the oxidant gas A through the oxidant supply path 4. When the supplied air flows downstream through a predetermined passage in contact with the oxidant electrode 2, a necessary amount of oxygen in the air undergoes an electrode reaction and is consumed, and the remaining gas a passes through the remaining gas discharge passage 5. It is discharged outside. [0003] The upstream side of the fuel electrode 3 is connected to a reformer 7 via a reformed gas supply path 6. The reformer 7 is supplied with a fuel gas X such as natural gas through a fuel gas supply passage 8 and a raw water Y required for a steam reforming reaction through a raw water supply passage 9. The reformer 7 includes a combustion unit 10 for heating itself. The raw fuel gas F is supplied to the combustion unit 10 through a raw fuel gas supply path 11. When the raw fuel gas F is burned in the combustion section 10, a steam reforming reaction between the fuel gas X and the raw water Y occurs in the reformer 7, and a hydrogen-rich reformed gas G is generated. The reformed gas G generated by the reformer 7 is supplied to the fuel electrode 3 via the reformed gas supply passage 6 and flows downstream through a predetermined passage in contact with the fuel electrode 3 when the reformed gas G is generated. The required amount of hydrogen in the electrode reacts and is consumed, and the remaining off-gas g is combined with the raw fuel gas F flow in the raw fuel gas supply path 11 via the off-gas discharge path 12. Although not disclosed in the above-mentioned prior art publication, a heat exchanger for lowering the temperature of the reformed gas G is disposed in the reformed gas supply passage 6. The heat exchanger lowers the temperature of the reformed gas from the high operating temperature of the reformer 4 to the low operating temperature of the electrolyte fuel cell 1. In the above conventional fuel cell power generation system, condensed water is supplied to the fuel electrode of the electrolyte fuel cell together with the reformed gas. Therefore, there is a problem that the power generation efficiency of the electrolyte fuel cell is low. Therefore, a technical problem of the present invention is to provide a fuel cell power generation system with improved power generation efficiency of an electrolyte fuel cell. Means for Solving the Problems The technical means of the present invention taken to solve the above technical problem is a reformer for producing a reformed gas from a fuel gas, a fuel electrode and an oxidizer. An electrolyte type fuel cell in which an electrolyte membrane is sandwiched between a pair of electrodes composed of a cathode, and which generates power using a reformed gas supplied to a fuel electrode and an oxidant gas supplied to an oxidant electrode, A heat exchanger that is arranged in a reformed gas supply path that supplies the reformed gas from the reformer to the fuel electrode of the electrolyte fuel cell and cools the reformed gas;
A fuel cell power generation system, comprising: a trap disposed on a reformed gas outlet side of a heat exchanger to drain condensed water from a reformed gas stream. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger for cooling a reformed gas which is disposed in a reformed gas supply path for supplying the reformed gas from a reformer to a fuel electrode of an electrolyte fuel cell. A trap for draining condensed water from the reformed gas stream is disposed on the reformed gas outlet side of the apparatus. Therefore, the reformed gas from which the condensed water is removed by the trap is supplied to the fuel electrode of the electrolyte fuel cell, and the power generation efficiency of the electrolyte fuel cell is increased. An embodiment showing a specific example of the above technical means will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing a configuration of a fuel cell power generation system according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the trap of FIG. 1, and FIG. 3 is a cross-sectional view of FIG. In FIG. 1, the same components as those of the prior art shown in FIG. 4 are denoted by the same reference numerals, and detailed description will be omitted. The temperature of the reformed gas G is supplied to a reformed gas supply path 6 for supplying the reformed gas G from the reformer 7 to the fuel electrode 3 of the electrolyte fuel cell 1. A heat exchanger 13 is provided for cooling from 700 ° C. to about 80 ° C., which is the operating temperature of the electrolyte fuel cell 1. The heat exchanger 13
This is a water heat exchanger that cools the reformed gas G with the cooling water W. A trap 15 for discharging condensed water D from the reformed gas G flow is disposed on the reformed gas outlet 14 side of the heat exchanger 13. A trap 16 for draining condensed water D from the off-gas g flow is disposed in the off-gas discharge path 12. A trap 17 for draining condensed water D from the remaining gas a stream is provided in the remaining gas discharge path 5. The traps 15, 16, 17 are float traps having a built-in steam-water separation unit. The traps 15, 16, and 17 are shown in FIGS.
Shown in The casing of the trap is formed by welding an upper body 21 made of a stainless steel thin plate into a cylindrical shape and a lower body 22 made of a stainless steel thin plate into a substantially hemispherical shape at the mating surfaces. An inlet 24 for introducing a mixed flow of gas and condensed water is attached to an upper side surface of the upper body 21. The gas outlet 31 is coaxial with the inlet 24 of the upper body 21.
Is attached. Disc-shaped water / water separation plates 32 and 33 as a water / water separation unit are respectively attached to the inlet 24 and the outlet 31 on the valve chamber 23 end. A valve chamber 23 is formed inside the casing,
A spherical closed float 26 is arranged in the valve chamber 23 in a free state. The lower body 22 is provided with a float seat 25 for sitting when the float 26 descends. The float seat 25 is formed in two protruding shapes toward the inside of the valve chamber 23 in parallel with the central axis of the valve port 27 which is opened and closed by the floating movement of the float 26 and extending in the parallel direction. At a position facing the float seat 25 of the lower main body 22, a through hole 30 is provided as a mounting portion for mounting a valve seat member 29 provided with a valve port 27 and a drain port 28 to the lower main body 22. The mixed flow of the gas and the condensed water flowing into the valve chamber 23 from the inlet 24 first collides with the steam-water separating plate 32 on the inlet side to perform the first-stage steam-water separation. The water drops downward, while the gas having a small mass does not drop, but again collides with the steam-water separator 33 on the outlet 31 side to perform the second-stage steam-water separation. The gas separated from the condensed water by the two-stage steam-water separation is exhausted from the outlet 31. The liquid that has dropped downward accumulates in the valve chamber 23,
The liquid level gradually rises to raise the float 26 by its buoyancy (the position shown by the broken line in FIG. 2), and the float 26 is separated from the float seat 25 and the valve port 27 to thereby provide the valve chamber 2
The condensed water in 3 is drained from the drain 28. When the condensed water is drained and the liquid level in the valve chamber 23 drops, the float 26
Descends and sits on the float seat 25 and the valve port 27, thereby preventing gas from leaking from the drain port 28. The condensed water D drained from the drain port 28 of the trap 15 passes through a condensed water drain channel 34, and the condensed water D drained from the drain port 28 of the trap 16 is condensed water drain channel 35.
, The condensed water D drained from the drain port 28 of the trap 17 is joined to the raw water Y flow in the raw water supply passage 9 via the condensed water drain passage 36. The condensed water D may be drained out of the system, but can be reused by joining the raw water Y. Since the reformed gas G from which the condensed water has been removed is exhausted from the outlet 31 of the trap 15, the power generation efficiency of the electrolyte fuel cell 1 can be increased. The off-gas g exhausted from the outlet 31 of the trap 16 may be exhausted, but by being combined with the raw fuel gas F flow,
Can be reused. Also, the exit 2 of the trap 16
Since the off gas g from which the condensed water is removed is exhausted from 4, the combustion efficiency of the combustion unit 10 can be increased. As described above, according to the present invention, the condensed water is drained from the reformed gas stream, and the reformed gas from which the condensed water is removed is supplied to the fuel electrode of the electrolyte fuel cell. As a result, the power generation efficiency of the electrolyte fuel cell can be increased, and an excellent effect that a highly efficient fuel cell power generation system can be provided is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of a fuel cell power generation system according to an embodiment of the present invention. FIG. 2 is a sectional view of the trap of FIG. 1; FIG. 3 is a sectional view taken along line AA of FIG. 2; FIG. 4 is a diagram showing a configuration of a conventional fuel cell power generation system. [Description of Signs] 1 polymer electrolyte fuel cell 2 oxidant electrode 3 fuel electrode 4 oxidant gas supply path 5 remaining gas discharge path 6 reformed gas supply path 7 reformer 8 fuel gas supply path 9 feed water Passage 10 Combustion unit 11 Raw fuel gas supply passage 12 Off gas discharge passage 13 Heat exchanger 14 Reformed gas outlets 15, 16, 17 Trap 23 Valve chamber 24 Inlet 25 Float seat 26 Float 27 Valve outlet 28 Drain outlet 31 Exit 32 Steam Separation plate 33 Steam-water separation plates 34, 35, 36 Condensate drainage channel

Claims (1)

Claims: 1. A reformer for producing a reformed gas from a fuel gas, and an electrolyte membrane sandwiched between a pair of electrodes comprising a fuel electrode and an oxidant electrode, and supplied to the fuel electrode. Fuel cell that generates power using the reformed gas supplied and the oxidant gas supplied to the oxidant electrode, and the reformed gas that supplies the reformed gas from the reformer to the fuel electrode of the electrolyte fuel cell A heat exchanger for cooling the reformed gas disposed in the supply path; and a trap disposed on the reformed gas outlet side of the heat exchanger for draining condensed water from the reformed gas stream. Fuel cell power generation system.