JP2008300304A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system in which an amount of moisture in offgas exhausted from a fuel cell body flowing into a reformer burner is reduced in a simple and economical composition. <P>SOLUTION: The fuel cell power generation system has a fuel treatment unit 2, a fuel cell body, an offgas supplying passage 8 for guiding the offgas exhausted from an anode directly to a reformer burner 3 on an upward slope, and a cooling water flowing passage 7 which circulates a cooling water from outside of the fuel cell body 1 to the inside of the fuel cell body 1. The fuel cell body 1 includes an anode separator made of a porous material, and a condensed water generated in the offgas supplying passage 8 is made to flow into the cooling water flowing passage 7 through the anode separator. The cooling water flowing passage 7 has a tank 4 for storing the cooling water to be supplied to the fuel cell body 1 and a cooling water pump 6 for sucking and sending the cooling water coming through the anode separator to the tank 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system, and more particularly to a fuel cell power generation system including a fuel processing device having a reformer burner.

  A fuel processing device for reforming a hydrocarbon-based fuel represented by city gas or LPG (liquefied natural gas) supplied from the outside into a hydrogen-rich gas, and a hydrogen-rich gas and oxygen obtained by the fuel processing device There is known a fuel cell power generation system including a fuel cell main body that generates a DC power by reacting with. In this system, the remaining fuel gas (off gas) that has not been consumed inside the fuel cell body is discharged from the anode electrode of the fuel cell body. The off gas is supplied to a reformer burner provided as heat supply means for supplying reaction heat of the reformer in the fuel processing apparatus, and is combusted by air supplied from the outside.

The off gas contains water mainly composed of water generated by the electrochemical reaction of the fuel cell body, and the water becomes a factor that deteriorates the combustibility in the reformer burner. Therefore, a device for removing moisture between the anode electrode of the fuel cell main body and the reformer burner and a device for discharging the removed moisture (condensed water) from the moisture removing device are required. (See Patent Document 1 and Patent Document 2).
Japanese Patent No. 2656262 JP 2006-147264 A

  The conventional fuel cell power generation system has the following problems in order to simplify the system, make it compact, and realize cost reduction. That is, in the conventional fuel cell power generation system, the off-gas discharged from the anode electrode is supplied to the condensed water tank through the anode electrode-condensed water tank pipe in a descending gradient from the fuel cell body. The condensed water tank is provided with a heat exchanging unit and condenses moisture contained in the offgas. Condensed water is discharged into the tank by a moisture removing device. The off gas from which moisture has been removed is supplied to the reformer burner from the condensate water tank in an ascending gradient through a condensate water tank-reformer burner pipe. In addition, a refrigerant pump and a refrigerant supply path are provided as means for supplying the refrigerant to the heat exchange unit.

  In the system having such a configuration, there are many auxiliary devices, and the system becomes complicated, such as control of the amount of refrigerant supplied to the heat exchange unit. In addition, there was a problem in terms of downsizing the package in order to secure the installation space for the incidental equipment and the slope of the piping. Furthermore, with a large number of parts, the off-gas flow passage must be made of stainless steel due to restrictions on combustible gas, which increases costs.

  The present invention solves the above-described problem, and an object thereof is to provide a simple and inexpensive configuration for reducing the amount of moisture in the off-gas discharged from the fuel cell main body flowing into the reformer burner. To do.

  In order to achieve the above object, a fuel cell power generation system according to the present invention comprises a fuel treatment device having a reformer burner for reforming a hydrocarbon-based fuel into a hydrogen-rich gas, an anode electrode and a cathode electrode. A fuel cell main body that generates direct-current power by reacting oxygen and the hydrogen-rich gas obtained in the fuel processing apparatus, and off-gas discharged from the anode electrode directly to the reformer burner in an upward gradient. And an off-gas supply path for guiding.

  ADVANTAGE OF THE INVENTION According to this invention, the quantity in which the water | moisture content in the off gas discharged | emitted from a fuel cell main body flows in into a reformer burner can be reduced with a simple and cheap structure.

  An embodiment of a fuel cell power generation system according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block system diagram showing a configuration of an embodiment of a fuel cell power generation system according to the present invention, and FIG. 2 shows a part of a cross section of a fuel cell stack of a fuel cell main body in the fuel cell power generation system of FIG. It is sectional drawing.

  The fuel cell main body 1 is composed of a fuel cell stack in which unit cells 21 are stacked in a plurality of stages as shown in FIG. The unit cell 21 includes a membrane electrode assembly (MEA) 28 and an anode separator 25 and a cathode separator 26 that are disposed therebetween. The membrane electrode assembly 28 includes a solid polymer membrane 22 disposed in the center, and an anode catalyst layer 23a and a cathode catalyst layer 24a sandwiching the membrane, and an anode electrode 23 and a cathode electrode 24 are formed therein. .

  A fuel gas flow passage 23 c is formed in a portion of the anode separator 25 that is in contact with the anode electrode 23. An oxidant gas flow passage 24c is formed in a portion of the cathode separator 26 that is in contact with the cathode electrode 24. Further, an in-battery cooling water flow passage 27 c is formed in a portion of the cathode separator 26 adjacent to the anode separator 25. The anode separator 25 and the cathode separator 26 are made of a porous material.

  A fuel gas containing hydrogen processed by the fuel processing device 2 (see FIG. 1) is supplied to the fuel gas flow passage 23c. An oxidant gas such as air is supplied to the oxidant gas flow passage 24c.

  Further, the cooling water flow passage 27c is supplied with cooling water through the cooling water flow passage 7 shown in FIG. 1, and the cooling of the fuel cell main body 1 is performed by circulating this cooling water. The cooling water flow passage 7 is configured to circulate through the cooling water pump 6 and the tank 4. Here, the cooling water pump 6 is disposed in the cooling water flow passage 7 on the downstream side of the in-battery cooling water flow passage 27c, and the pressure in the in-battery cooling water flow passage 27c is maintained at a negative pressure.

  The off gas discharged from the anode electrode 23 is directly supplied from the anode electrode 23 to the reformer burner 3 through the off gas supply path 8 in an upward gradient.

  Condensed water generated between the anode 23 and the reformer burner 3 flows backward to the anode 23 through the off-gas supply path 8 due to gravity. The condensed water flowing into the anode electrode 23 flows into the in-battery cooling water flow passage 27c that is in a negative pressure state through the porous material 11 in the fuel cell main body 1, and further flows into the cooling water flow passage 7 to thereby cause the battery main body 1 to flow. Removed from.

  Specifically, the condensed water in the fuel gas flow passage 23c having a positive pressure is removed into the in-battery cooling water flow passage 27c adjacent to the fuel gas flow passage 23c through the anode separator 25 made of a porous material.

  By adopting the above configuration, the combustibility in the reformer burner 3 can be kept good without using incidental equipment such as a condensed water tank for discharging condensed water. As a result, the system in the fuel cell power generation system can be simplified, downsized, and cost can be reduced.

1 is a block system diagram showing a configuration of an embodiment of a fuel cell power generation system according to the present invention. FIG. 2 is a cross-sectional view showing a part of a cross section of a fuel cell stack of a fuel cell main body in the fuel cell power generation system of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell main body 2 ... Fuel processing apparatus 3 ... Reformer burner 4 ... Tank 6 ... Cooling water pump 7 ... Cooling water flow path 8 ... Off gas supply path 11・ ・ Porous material 12 ・ ・ ・ Condensed water 21 ・ ・ ・ Unit battery 22 ・ ・ ・ Solid polymer membrane 23 ・ ・ ・ Anode electrode 23 a ・ ・ ・ Anode catalyst layer 23 c ・ ・ ・ Fuel gas flow passage 24 ・ ・ ・Cathode electrode 24a ... Cathode catalyst layer 24c ... Oxidant gas flow passage 25 ... Anode separator 26 ... Cathode separator 27c ... In-battery cooling water flow passage 28 ... Membrane electrode assembly (MEA)

Claims (3)

A fuel processor having a reformer burner for reforming a hydrocarbon-based fuel into a hydrogen-rich gas; and
A fuel cell body having an anode electrode and a cathode electrode, which reacts oxygen with a hydrogen-rich gas obtained by the fuel processing device to produce DC power;
An off-gas supply path for directing off-gas discharged from the anode electrode directly to the reformer burner in an upward gradient;
A fuel cell power generation system comprising: A cooling water flow passage for circulating cooling water from the outside of the fuel cell body into the fuel cell body;
The fuel cell body includes an anode separator made of a porous material,
2. The fuel cell power generation system according to claim 1, wherein the condensed water generated in the off-gas supply path is configured to flow into the cooling water flow path through the anode separator.   The cooling water flow passage has a tank for storing cooling water supplied to the fuel cell main body, and a cooling water pump that sucks the cooling water that has passed through the anode separator and sends the cooling water to the tank. The fuel cell power generation system according to claim 2.

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