JP3280164B2 - Steam condensed water circulation device for fuel cell power generator and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam condensed water circulating apparatus for a fuel cell power generator for recovering heat from steam generated in a fuel cell main body, condensing the same, and circulating it again as cooling water to the fuel cell main body, and a control method therefor. .

[0002]

2. Description of the Related Art In a fuel cell power generator, cooling water is supplied to a fuel cell main body, and heat generated due to power generation by an electrochemical reaction is taken out as steam to effectively utilize the heat and condense the steam. In general, a method of using the cooling water again for the fuel cell main body is adopted.

FIG. 2 is a basic system diagram showing a conventional typical steam condensed water circulation device of a fuel cell power generation device. In the figure, a fuel cell main body 1 is shown as a model, and a single cell in which an electrolyte layer (not shown) is sandwiched between a fuel electrode 2 and an air electrode 3 is laminated by appropriately inserting a cooling plate 4. It is configured. Cooling water for removing heat generated by the fuel cell body 1 through the cooling plate 4 is supplied to a circulation pump 9.
Is supplied from the steam separator 5 through the cooling water supply channel 7. The steam that has flowed through the cooling plate 4 and has been heated by the heat generated by the fuel cell main body 1 is returned to the steam separator 5 again through the cooling water discharge passage 8.

The pressure of the steam separator 5 is controlled by a pressure regulating valve 10.
To release heat to the heat recovery device 31. The heat recovery device 31 recovers heat to the outside by, for example, exchanging heat of the sent high-temperature steam with cooling water sent from the outside, and correspondingly cools the steam. The condensed water of the cooled steam is stored in the condensed water tank 32. When the level of the condensed water stored in the condensed water tank 32 falls within a predetermined level range, the condensed water pump 33 is turned on and off. When the stored amount increases, the condensed water is returned to the steam separator 5. . The manual valve 15 provided in the path from the condensed water pump 33 to the steam separator 5 is normally open during normal operation, and the control valve 14 is connected to the steam separator 5 (not shown). This valve is closed when the liquid level becomes higher than a predetermined value, and is normally in an open state. Therefore, the condensed water tank 3
The amount of condensed water sent from 2 to the steam separator 5 is controlled by the on / off of the condensed water pump 33.

[0005] Makeup water tank 21, makeup water supply pump 2
2. The system composed of the water treatment device 23 and the make-up water control valve 24 is a system that supplies make-up water when the amount of water stored in the steam separator 5 is insufficient, and a level gauge attached to the steam separator 5. 20 according to the signal detected by the control valve 20
4 is controlled to open and close.

[0006]

As described above, in the conventional fuel cell power generator, the steam generated by heating the cooling water sent to the fuel cell body is sent to a heat recovery facility to effectively recover the heat. Further, an efficient steam condensed water circulating apparatus for returning the steam to the steam separator and recirculating it as cooling water is constituted.

However, even in the steam condensed water circulating apparatus according to this configuration, the supply of the condensed water stored in the condensed water tank to the steam separator is performed by controlling the operation of the condensed water pump on and off. Therefore, there is a problem that the amount of steam generated in the steam separator fluctuates greatly. That is, since the temperature of the condensed water is essentially lower than the temperature of the steam separator, when the condensed water pump is operated and the condensed water is supplied to the steam separator, the temperature of the steam separator falls and the amount of generated steam is reduced. Decrease. On the other hand, when the condensed water pump is stopped, the supply of low-temperature condensed water is stopped, so that the temperature of the steam separator rises relatively and the amount of generated steam increases. When the amount of steam generated in the steam separator fluctuates greatly,
The flow rate sent to the heat recovery equipment fluctuates greatly, making stable operation of the apparatus difficult. Further, when one heat recovery facility is operated by a plurality of fuel cell power generators, it is difficult to operate the heat recovery facility if the amount of steam generated from each fuel cell power generator fluctuates greatly as described above. In addition, there is a problem that a condensed water flow control device must be installed in the heat recovery equipment.

Further, in the above-described conventional configuration, an efficient operation method is employed in which all the condensed water is returned to the steam separator and recirculated. However, if the condensed water is continuously used for a long time, the condensed water remains in the system. There has been a problem that the water quality gradually deteriorates due to the contamination, and the characteristics of the fuel cell power generator deteriorate. Further, in this system, it is an essential condition that the entire circulating system is clean, and during operation, it is necessary to perform a trial operation and clean the equipment components including the heat recovery equipment in advance.

The present invention has been made on the basis of the above background, and has the following objects. (1) The amount of steam generated from a steam separator of a fuel cell power generation device is controlled to be substantially constant, and heat recovery equipment is provided. An object of the present invention is to provide a steam condensed water circulation device that can be operated stably and a control method thereof. (2) To provide a steam condensate circulating apparatus and a control method thereof, which control the quality of cooling water of a steam separator of a fuel cell power generation apparatus so as to satisfy a certain level and enable stable power generation characteristics over a long period of time. It is in.

[0010]

In order to achieve the above object, the present invention provides: (1) a steam separator for supplying cooling water to a fuel cell body and introducing steam after cooling; It has a heat recovery facility that introduces steam from the separator to extract heat, a condensed water tank that stores water condensed in the heat recovery facility, and a condensed water pump that returns condensed water in the condensed water tank to the steam separator again. In the steam condensed water circulation device of the fuel cell power generator, a flow rate measuring means of the steam sent from the steam separator to the heat recovery equipment, a flow rate measuring means of the condensed water sent from the condensed water tank to the steam separator, A flow control valve for condensed water, which is incorporated in a piping system from the condensed water tank to the steam separator and is controlled by a flow signal detected by the two flow measuring means, is provided.

(2) In the above-mentioned steam condensed water circulating apparatus, a pipe from the condensed water tank to the condensed water flow control valve is connected to the steam separator via at least a water treatment device. A branch pipe with an on-off valve will be provided.

[0012]

[Operation] If the steam condensed water circulation device of the fuel cell power generator is configured as described above, (1) During normal operation, two flow signals detected by the steam flow measuring means and the condensed water flow measuring means are used. By controlling the valve opening of the condensed water flow control valve so that the steam flow rate and the condensed water flow rate are the same, unlike the conventional on-off control, the condensed water flows to the steam separator in a steady state. Temperature fluctuations of the steam separator are suppressed to a very small level, an almost constant steam flow rate is sent to the heat recovery equipment, and an almost constant condensate flow rate is similarly supplied to the steam separator. Becomes Therefore, the heat recovery equipment can be operated stably. In the case where a branch pipe connected to the steam separator via the water treatment device is provided, the on-off valve of the branch pipe is closed and the valve opening of the condensed water flow control valve is closed as described above. The same effect can be obtained by controlling.

(2) When the quality of the condensed water deteriorates due to the operation for a considerably long period of time and becomes insufficient as cooling water for the fuel cell body, the on-off valve of the branch pipe is opened and the steam flow rate is measured. If the flow rate of the condensed water is controlled so that the flow rate of the condensed water becomes a constant ratio of the steam flow rate by the two flow rate signals detected by the means and the condensed water flow rate measuring means, The condensed water passes through a branch pipe, reaches a makeup water tank, is purified through a water treatment device, is supplied to a steam separator, and the cooling water is entirely purified and the water quality is improved. Therefore, by appropriately using this method, it is possible to maintain sufficient water quality as cooling water for the fuel cell body.

Further, the manual valve to the branch pipe is opened, and the manual valve of the pipe leading to the steam separator through the flow control valve of the condensed water is closed, so that the entire amount of the condensed water is supplied from the branch pipe to the makeup water tank. And the method of supplying the water to the steam separator through the water treatment apparatus, the clean cooling water is supplied to the fuel cell body even if the heat recovery equipment is not cleaned, so that the fuel which was conventionally impossible Simultaneous test operation of the battery body and the heat recovery equipment can be performed.

[0015]

FIG. 1 is a basic system diagram showing one embodiment of a steam condensed water circulation device of a fuel cell power generator according to the present invention.
Components having the same functions as those of the conventional example shown in FIG. 2 are denoted by the same reference numerals. The difference between the steam condensed water circulating apparatus shown in the drawing and the conventional example is as follows.

An external heat recovery facility 3 from the steam separator 5
A steam flow meter 11 is attached to a pipe for supplying steam to the steam turbine 1. A pipe for returning condensed water from the condensed water tank 32 to the steam separator 5, a condensed water flow meter 12, a flow regulating valve 13 controlled by a detection signal from the condensed water flow meter 12 and the steam flow meter 11, And a manual valve 15.

A return pipe from the condensed water tank 32 is provided with a condensed water branch pipe 17 having a manual valve 16 and connected to the makeup water tank 21. In the steam condensed water circulation device configured as described above, the flow rate of the condensed water can be adjusted by the flow control valve 13, so that the steam condensed water can be controlled in accordance with the use conditions. (1) In the steady operation state of the fuel cell power generator, the flow rate regulating valve 13 controls the flow rate of the condensed water so that the two flow rates obtained by the detection signals of the steam flow meter 11 and the condensed water flow meter 12 become the same. Is controlled, the condensed water is supplied to the steam separator 5 constantly, so that the temperature fluctuation of the steam separator 5 is suppressed very small, and a substantially constant steam flow rate is sent to the heat recovery facility 31. Can be Therefore, the heat recovery facility 31 can be operated stably.

(2) If the quality of the condensed water deteriorates due to long-term operation or the like and becomes insufficient as cooling water for the fuel cell body, the manual valve 16 of the condensed water branch pipe 17 is opened,
In addition, based on the detection signals from the steam flow meter 11 and the condensed water flow meter 12, the condensed water flow rate is set to a fixed rate R (0 <R <
If the valve opening of the flow rate control valve 13 for condensed water is controlled so as to satisfy 1), the condensed water corresponding to the ratio of (1-R) passes through the branch pipe to the makeup water tank, and is subjected to water treatment. After being purified through the apparatus, it is supplied to the steam separator, and the cooling water is entirely purified and the water quality is improved.

(3) Further, the manual valve 16 of the condensed water branch pipe 17 is opened and the manual valve 15 is closed, and the entire amount of the condensed water is supplied to the steam separator 5 through the makeup water tank 21 and the water treatment device 23. If the supply method is adopted, clean cooling water is supplied to the fuel cell main body 1 even if the heat recovery equipment 31 is not cleaned. Simultaneous test operation with the X.31 is possible.

[0020]

According to the present invention, as described above, a steam separator for supplying cooling water to the fuel cell main body and introducing steam after cooling, and introducing steam from the steam separator to extract heat. Heat recovery equipment, a condensed water tank for storing water condensed in the heat recovery equipment, and a condensed water pump for returning the condensed water in the condensed water tank to the steam separator again in a steam condensed water circulation device for a fuel cell power generator, The flow rate measuring means of the steam supplied from the steam separator to the heat recovery equipment, the flow rate measuring means of the condensed water sent from the condensed water tank to the steam separator, and the piping system from the condensed water tank to the steam separator are incorporated. A condensed water flow control valve controlled by a flow signal detected by the above two flow measuring means, and further from the condensed water tank to the condensed water flow control valve. A branch pipe that can communicate with the make-up water tank by opening and closing a manual valve is provided in the pipe to be connected to the steam separator through a water treatment device that purifies the make-up water. By controlling the steam flow rate and the condensed water flow rate flowing through the flow rate adjustment valve by the valve,
Since the condensed water is constantly supplied to the steam separator, the amount of steam generated in the steam separator was stabilized, and the stable operation of the heat recovery equipment became possible.

(2) The ratio between the flow rate of the condensed water and the flow rate of the steam flowing through the flow control valve is kept constant, and a part of the condensed water is returned to the steam separator through the branch pipe and the water treatment device. By controlling the condensate water,
It has become possible to maintain the water quality level within a certain range. (3) Further, by controlling the entire amount of condensed water to return to the steam separator through the branch pipe through the water treatment device, the test operation of the heat recovery equipment can be performed simultaneously with the test operation of the fuel cell power generator. The test period can be shortened.

[Brief description of the drawings]

FIG. 1 is a basic system diagram showing one embodiment of a steam condensed water circulation device of a fuel cell power generation device according to the present invention.

FIG. 2 is a basic system diagram showing a steam condensed water circulation device of a conventional fuel cell power generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell main body 4 Cooling plate 5 Steam separator 9 Circulation pump 10 Pressure regulating valve 11 Steam flow meter 12 Condensed water flow meter 13 Flow regulating valve 14 Control valve 15, 16 Manual valve 17 Branch pipe 21 Makeup water tank 22 Supply water Pump 23 water treatment device 24 makeup water control valve 31 heat recovery equipment 32 condensed water tank 33 condensed water pump

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-73855 (JP, A) JP-A-60-208067 (JP, A) JP-A-2-168573 (JP, A) JP-A-2- 10664 (JP, A) JP-A-5-41232 (JP, A) JP-A-5-211066 (JP, A) JP-A-6-275294 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01M 8/04 H01M 8/06

Claims (6)

(57) [Claims] 1. A steam separator for supplying cooling water to a fuel cell main body and introducing steam after cooling, a heat recovery facility for introducing steam from the steam separator and extracting heat, and a heat recovery facility. A condensed water tank for storing condensed water, and a condensed water pump for supplying condensed water in the condensed water tank to the steam separator, wherein the steam sent from the steam separator to the heat recovery facility is The flow rate measuring means, the flow rate measuring means of the condensed water sent from the condensed water tank to the steam separator, and incorporated in the piping system from the condensed water tank to the steam separator, the two flow rate measuring means A steam condensed water circulation device for a fuel cell power generator, comprising: a flow control valve controlled by a detected flow signal. 2. A steam condensate circulating apparatus for a fuel cell power generator according to claim 1, wherein a pipe from said condensed water tank to said flow regulating valve is connected to said steam separator via at least an on-off valve and a water treatment device. A steam condensate circulating device for a fuel cell power generator, comprising a branch pipe connected to the steam generator. 3. The steam condensed water circulation device for a fuel cell power generator according to claim 1, wherein the two flow rates detected by the steam flow rate measuring means and the condensed water flow rate measuring means are the same. And controlling the flow rate regulating valve. 4. The steam condensed water circulation device for a fuel cell power generator according to claim 2, wherein an on-off valve attached to said branch pipe is closed, and said steam flow rate measuring means and said condensed water flow rate measuring means are provided. And controlling the flow rate regulating valve so that the two flow rates detected by the method are the same. 5. The steam condensate water circulating device for a fuel cell power generator according to claim 2, wherein an on-off valve attached to said branch pipe is opened, and said flow rate detected by said flow rate measuring means of said condensed water and said flow rate A method for controlling a steam condensed water circulation device, wherein the flow rate control valve is controlled so that a ratio with a flow rate detected by a steam flow rate measuring means is constant. 6. The steam condensate circulating device for a fuel cell power generator according to claim 2, wherein the entire amount of condensed water from said condensed water tank flows through said branch pipe, and said steam separator is passed through said water treatment device. A method for controlling a steam condensed water circulating apparatus, characterized by circulating water.