JPH02265170A - Fuel cell power generating system - Google Patents

Abstract

PURPOSE:To keep differential pressure between electrodes constant with a simple system by raising pressure of an oxidizing agent and that of a reducing agent so that differential pressure between the oxidizing agent and the reducing agent of a fuel cell is kept constant. CONSTITUTION:An oxidizing agent and a reducing agent whose pressures are raised to the same level with a turbine compressor 4 having a common axis are supplied to an air electrode 3 and a fuel electrode 2. Combustion gas for driving the turbine compressor 4 is produced with an auxiliary combustor 5. The oxidizing agent and the reducing agent whose pressures are raised with the turbine compressor are supplied to the electrodes 3, 2 through an auxiliary combustor fuel control valve 6 and an auxiliary combustor air control valve 7. The necessary amounts of fuel and oxidizing agent are supplied by controlling the valves 6, 7 so that pressure detected with a pressure detector 9 is kept constant. At the same time, however, the valves 6, 7 are preferentially operated so that differential pressure between electrodes detected with a differential pressure detector 10 is made constant. Pressures of oxidizing agent and reducing agent are raised, and operation pressure of the fuel cell and differential pressure between electrodes are surely controlled. A system is simplified.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention raises the pressure of an oxidizing agent and a reducing agent at the same time using two compressors configured with the same shaft, and increases the differential pressure between the poles of a fuel cell. This invention relates to a fuel cell power generation device that is maintained at a constant level.

(Prior art) As is well known, a fuel cell is a power generating element that generates electricity by reacting a reducing agent at an anode and an oxidizing agent at a cathode through a thin film, and the differential pressure between the two electrodes is a specified value. If the amount exceeds 100%, the thin film may be destroyed. However, in the past, the pressure of the oxidizing agent and the reducing agent were increased independently, and the differential pressure between the electrodes was adjusted by adjusting the pressure loss in the piping after the fuel cell outlet.

(Problem to be solved by the invention) However, in the conventional configuration, the pressure of the oxidizing agent and the reducing agent were increased independently, making it difficult to control the differential pressure between the electrodes.
If either the oxidizing agent or the reducing agent pressure booster fluctuates, it is impossible to maintain the differential pressure constant and continue operation. Furthermore, each requires independent boosting equipment, making the system complex.

An object of the present invention is to provide a fuel cell power generation device that can maintain a constant differential pressure between battery electrodes with a simple system.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a fuel cell power generation system mainly containing air as an oxidizing agent and hydrogen as a reducing agent. a turbine compressor consisting of the same shaft for increasing the pressure of the fuel to the same operating pressure, an auxiliary combustor for generating combustion gas that becomes the power source for the turbine compressor, and the oxidizer and reducing agent at the fuel cell inlet. A differential pressure detector for detecting the differential pressure of The fuel cell is characterized in that it is equipped with piping and a flow rate adjusting means, and increases the pressure of the oxidizing agent and the reducing agent so that the pressure difference between the oxidizing agent and the reducing agent of the fuel cell is always constant.

(Function) In the present invention configured as described above, the pressure difference between the oxidizing agent and the reducing agent in the fuel cell population is increased so as to be constant, and as a result, the differential pressure between the battery electrodes is controlled to be constant.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure shows a block diagram of a fuel cell device according to an embodiment of the present invention. The fuel cell body 1 is roughly divided into a fuel electrode 2 and an air electrode 3.

An oxidizing agent and a reducing agent pressurized to the same pressure are supplied to the fuel electrode 2 and the air electrode 3, and a turbine compressor 4 having the same shaft is used to increase the pressure. In order to drive this turbine compressor 4, combustion gas is generated by an auxiliary combustor 5, and the oxidizing agent and reducing agent, which have been pressurized by the turbine compressor, are used as fuel and oxidizing agent for the auxiliary combustor fuel control valve 6 and the auxiliary combustor. It is introduced via the combustor air control valve 7.

The control valves 6 and 7 are controlled as follows. As a driving source for the turbo compressor 4, the combustion gas obtained by burning the exhaust fuel and exhaust oxidizer from the fuel cell in the reformer 8 and using the heat for a reforming reaction is mainly used, but due to load fluctuations, etc. In this case, it is not possible to operate the turbine compressor at a constant reference pressure measured by the pressure detector 9 provided at the inlet of the turbine. Therefore, the necessary fuel oxidizer is supplied from the valves 6 and 7 so that the pressure detected by the pressure detector 9 is constant, but at the same time, the differential pressure between the fuel cell electrodes is detected by the differential pressure detector 10. The valves 6 and 7 are operated with priority given to keeping the value constant.

Therefore, it is not possible to accurately control the pressure detected by the pressure detector 9 to the set value using only the valve 6.7, but it is necessary to release the pressure directly from the auxiliary combustor to the atmosphere in any operating range. Pressure relief valve installed in the line 1
1 is set to be slightly open, and the turbine inlet pressure, which is expected to fluctuate slightly, is corrected by the pressure relief valve 11 by giving priority to control of the interpole differential pressure.

The above control method will be explained using FIG. 2. A controller 15 sends operation signals 13 and 14 to the valves 6 and 7 so as to keep the turbine inlet pressure 12 detected by the detector 9 constant.
Calculate and output. On the other hand, the controller 19 calculates and outputs operation signals 17 and 18 to the valves 6 and 7 so that the differential pressure 16 between the battery electrodes detected by the differential pressure detector 10 is kept constant. Actual operation signals to the valve are signals 13 and 1 for valve 6.
For valve 7, signals 14 and 18 are added. In such a configuration, priority is given to control to keep the interelectrode differential pressure 16 constant, so the valve 11 is driven by the operation signal 20 so as to keep the pressure 12 constant.

[Effects of the Invention] As described above, according to the present invention, both the oxidizing agent and the reducing agent are pressurized by the same turbine compressor, thereby reliably controlling the operating pressure of the fuel cell and the differential pressure between the cell electrodes, and improving the system. It can be greatly simplified.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the fuel cell power generating apparatus of the present invention, and FIG. 2 is a block diagram showing a control method in the configuration shown in FIG. 1. 1... Fuel cell body 2... Fuel electrode 3... Air electrode 4... Turbine compressor 5... Auxiliary fuel electrode 6... Auxiliary combustor fuel control valve 7... Auxiliary combustor air Control valve 8...Renovation 15, 19...Controller agent Patent attorney Yudo Noriyoshi Chika Ken Daishimaru

Claims (1)

[Claims] In a fuel cell power generation device whose main components are air as an oxidizing agent and hydrogen as a reducing agent, there is provided a turbine compressor having the same shaft for boosting the pressure of the oxidizing agent and the reducing agent to the same operating pressure; An auxiliary combustor for generating combustion gas that serves as a power source, a differential pressure detector for detecting the differential pressure between the oxidizing agent and the reducing agent at the fuel cell inlet, and a differential pressure detector for maintaining this differential pressure constant and controlling the battery operating pressure. The oxidizing agent and the reducing agent are provided with piping and flow rate adjusting means for respectively introducing a portion of the oxidizing agent and reducing agent into the auxiliary combustor so as to keep the pressure constant, so that the pressure difference between the oxidizing agent and the reducing agent in the fuel cell is always maintained constant. A fuel cell power generation device characterized by increasing the pressure of an oxidizing agent and a reducing agent so that the pressure is constant.