JP3111628B2 - Fuel cell power generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention purifies condensed water and tap water containing impurities by an ion exchange type water treatment apparatus.
The present invention relates to a water treatment system for a fuel cell power generator for replenishing fuel cell cooling water or raw fuel reforming reaction water, and more particularly to a water treatment system equipped with an ion-exchange type water treatment device that facilitates refilling of ion-exchange resin. .

[0002]

2. Description of the Related Art In order to operate a fuel cell with high efficiency for a long period of time, heat generated by a cell reaction is removed and the temperature distribution in a unit cell stack (called a stack) is changed to a predetermined operating temperature (phosphoric acid). It is required to keep the temperature of the fuel cell as uniform as possible at around 190 ° C. Therefore, a water-cooled fuel cell is known in which a stack is formed by stacking cooling plates between blocks with a plurality of unit cells as one block, and cooling water flowing as cooling medium flows through cooling pipes embedded in the cooling plates. Have been. Further, in a water-cooled fuel cell, the cooling water is required to have as low an electric conductivity as possible (high electric resistance) in order to prevent a liquid junction from being generated between the cooling plates at different potentials. There is known a water circulation system provided with a water treatment system for replenishing ion-exchanged water.

FIG. 3 is a configuration diagram showing a conventional water treatment system for a water-cooled fuel cell. In the figure, a fuel gas is supplied from a fuel reformer 2 to a fuel electrode of a fuel cell (stack) 1 composed of a stack of unit cells, and reaction air is supplied to a pneumatic electrode from a blower 1B. Power is generated based on an electrochemical reaction in which hydrogen and oxygen directly react between the electrodes. In the fuel cell, a cooling plate 3 is stacked for each of a plurality of unit cells, and a plurality of cooling pipes embedded in the cooling plate 3 are provided with a circulating pump 4P and a steam separator 4P arranged outside via an insulating joint. Is connected to the circulating system 10 of the cooling water 6 containing. The steam separator 4 contains cooling water 6 that is lower than the operating temperature of the fuel cell by a predetermined temperature. By circulating the cooling water 6 to the cooling plate 3 by a circulation pump 4P, the heat generated by the power generation is exhausted. The fuel cell stack 1
Is maintained at its operating temperature. Further, a large amount of power generation water or combustion generation is contained in the air off gas 1G discharged from the air electrode and the combustion exhaust gas 2G generated by burning the residual hydrogen in the fuel off gas 1F with the burner of the fuel reformer 2. Since water is contained, the water contained in the air off-gas and the combustion exhaust gas as water vapor is cooled by the condensing condenser 5, collected as condensed water 7, and supplied to the water treatment system.

If the electric conductivity of the cooling water 6 is high, a short-circuit current flows between the cooling plates through the cooling water in the insulating joint connecting the cooling pipes to each other. Parts are wasted. Therefore, the water treatment system 11 is connected to the cooling water circulation system in order to maintain the electric conductivity of the cooling water 6 at 1 μS / cm or less. That is, the water treatment system 11 includes the condensing condenser 5
The condensed water 7 collected in step 2 is guided to an auxiliary water tank 12 to form a mixed water 8 to which tap water is appropriately added, and the mixed water 8 is sent to an ion-exchange type water treatment device 15 via a pump 13 and a cooler 14, thereby obtaining The low-conductivity ion-exchanged water 9 was added to the cooling water 6 as makeup water, and the electric conductivity of the cooling water 6 was 1 μS /
cm or less. The supply amount of the make-up water 9 is determined by the shortage generated when the steam in the steam separator 4 is added to the raw fuel as the reforming reaction water and supplied to the fuel reformer 2 or the cooling water 6. It is controlled in accordance with the amount of replenishment for the shortage caused by discharging to the outside as blow water.

FIG. 4 is a system configuration diagram showing a conventional ion-exchange type water treatment apparatus.
Is an ion exchange resin cylinder 16 filled with ion exchange resin.
And an electric conductivity sensor 17 connected to the discharge side thereof, and ion-exchanges impurities in the mixed water 8 supplied through an inlet valve 18 to make low-conductivity make-up water 9, and an outlet valve The electric conductivity of the make-up water 9 is monitored by an electric conductivity sensor 17 while the electric conductivity of the make-up water 9 is monitored via an electric conductivity sensor 17 when the electric conductivity exceeds, for example, 1 μS / cm. When it is determined that the resin has reached the end of its life, the valves 18 and 19 are closed and the ion exchange resin in the ion exchange resin cylinder 16 is replaced.

FIG. 5 is a system configuration diagram showing a different conventional ion-exchange type water treatment apparatus.
6A, 16B and 16C, and the conductivity sensors 17A, 17B,
Is different from the above-described ion-exchange type water treatment apparatus in that the ion-exchanged water treatment apparatus has the property that the ion-exchange capacity decreases sequentially from the upstream-side ion-exchange resin cylinder. The decrease in conductivity is monitored by a conductivity sensor, and the service life of the last stage is empirically predicted from the operating time corresponding to the resin life of the first stage and the resin life of the second stage. By exchanging the resin in the cylinder, the makeup water 9 having a conductivity exceeding 1 μS / cm is prevented from being supplied to the cooling water circulation system 10 by mistake.

FIG. 6 is a system configuration diagram showing another conventional ion-exchange type water treatment apparatus. Valves 18 and 19 in FIG. 5 are replaced with three-way switching valves 22 and 23, and the three-way switching valves 22 and 23 are provided on the anti-ion exchange resin cylinder side. A bypass pipe line 21 having a spare ion exchange resin cylinder 16D is connected, and the makeup water 9 is supplied to the cooling water circulation system 10 via a three-way switching valve 24, and an electric conductivity sensor is provided on the discharge side of the three-way switching valve 23. 17C, the ion exchange resin of the ion exchange resin tubes 16A, 16B, and 16C can be exchanged in a state where the makeup water is supplied via the preliminary ion exchange resin tube 16D. Different from the prior art.

[0008]

The electrical conductivity of the water purified by the ion exchange resin tube has a property of rapidly deteriorating at the end of the life of the ion exchange resin. Therefore, even if no abnormality is observed in the electrical conductivity of the make-up water 9 when the electrical conductivity of the make-up water 9 is monitored by the electrical conductivity sensor 17 in FIG. 4, the electrical conductivity may be deteriorated during a monitoring suspension period, for example, a holiday. is there. In addition, it is often the case that a professional trader is required to replace the ion-exchange resin, and it is not rare that it takes several days from the occurrence of an abnormality in the conductivity to the completion of the replacement operation of the ion-exchange resin. As a result, make-up water 9 having high conductivity
Is supplied to the cooling water circulating system 10 for several days. During this time, there is a problem that a liquid junction occurs in the fuel cell and power generation is wasted.

In addition, since the remaining life of the ion-exchange resin cylinder 16C at the last stage can be predicted by adopting the configuration shown in FIG. 5, it is possible to arrange the ion-exchange resin exchange work earlier. However, since the ion-exchange resin cylinder is usually divided into three parts of the same size, there is a waste that the exchange work is performed while the ion-exchange resin in the ion-exchange resin cylinder 16C in the final stage is left unused. Further, since three sets of the ion exchange resin cylinder and the conductivity sensor are required, there arises a problem that the ion exchange type water treatment apparatus becomes large.

On the other hand, by providing the bypass piping 21 having the spare ion exchange resin cylinder 16D as shown in FIG. 6, it is possible to carry out the ion exchange resin exchange work without stopping the supply of the makeup water 9. However, since the spare ion-exchange resin tube is not used at all times, water is stagnant, and the problem that poor quality water is supplied to the cooling water circulation system 10 as makeup water 9 in the early stage of use occurs, and this is avoided. In order to do so, a three-way switching valve 24 must be added, a troublesome operation of draining poor-quality water to the outside and then supplying makeup water is required, and the configuration of the ion-exchange type water treatment apparatus is further complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ion-exchange type water treatment apparatus in which the operation of replacing the ion-exchange resin and the prediction of the exchange time are simple and accurate, the ion-exchange resin is not wasted, and the structure of the apparatus is simple. .

[0012]

According to the present invention, a water condensate is obtained by condensing air off-gas of a fuel cell and water vapor in combustion exhaust gas of a fuel reformer by a condensing condenser. Tap water is mixed with condensed water, and this mixed water is supplied as low-conductivity water through an ion-exchange type water treatment device. Water treatment equipment,
A main ion exchange resin tube, an auxiliary ion exchange resin tube connected in series at a subsequent stage, and an electric conductivity monitoring means provided between the main ion exchange resin tube and the auxiliary ion exchange resin tube; The auxiliary ion-exchange resin cylinder is not longer than the set value during a period from when the conductivity monitoring unit detects that the electric conductivity of the make-up water has exceeded the set value until the resin exchange of the main ion-exchange resin cylinder is completed. An amount of ion-exchange resin capable of discharging make-up water having the electric conductivity described above is included.

Further, the ion-exchange type water treatment apparatus can arbitrarily select a main ion-exchange resin cylinder or an auxiliary ion-exchange resin cylinder without stopping discharge of make-up water, thereby enabling refilling of the ion-exchange resin. A bypass pipe line, for example, a three-way switching valve for switching the mixed water between the main ion exchange resin cylinder side and the bypass pipe side, and a three-way switching valve for switching the discharge of make-up water between the bypass pipe side and the auxiliary ion exchange resin cylinder side. A pair of stop valves connected in series between the main ion exchange resin cylinder and the auxiliary ion exchange resin cylinder, and a branch pipe communicating with the intermediate point of the pair of stop valves and the bypass pipe, A bypass pipe having an electric conductivity monitoring means is provided on the main ion exchange resin cylinder side of the pair of stop valves.

[0014]

In the structure of the present invention, the ion-exchange type water treatment apparatus includes a main ion-exchange resin tube, an auxiliary ion-exchange resin tube connected in series in a subsequent stage, the main ion-exchange resin tube and the auxiliary ion-exchange resin tube. The auxiliary ion-exchange resin cylinder is connected to the auxiliary ion-exchange resin cylinder after detecting that the electric conductivity of the make-up water has exceeded a set value. During the period until the resin exchange of the ion exchange resin cylinder is completed, the amount of ion exchange resin capable of discharging the replenishing water having the electric conductivity equal to or less than the set value is included, so that the electric conductivity is reduced due to a delay in the exchange time. The function of preventing the occurrence of liquid junction due to the supply of high supply water to the cooling water circulation system and minimizing the remaining use of the ion exchange resin in the auxiliary ion exchange resin cylinder is obtained. In addition, the main ion exchange resin cylinder can be filled with an ion exchange resin in an amount corresponding to a predetermined life period into one ion exchange resin cylinder, thereby simplifying the configuration of the apparatus, and using only one conductivity sensor. As a result, the size of the ion-exchange type water treatment apparatus can be reduced, and the function of reducing the installation space can be obtained.

Further, the ion-exchange type water treatment apparatus can arbitrarily select the main ion-exchange resin cylinder or the auxiliary ion-exchange resin cylinder without stopping the discharge of make-up water, and can refill the ion-exchange resin. By providing a pipeline, especially a bypass pipeline that does not have a spare ion-exchange resin cylinder, the ion-exchange resin can be exchanged efficiently without stopping the supply of make-up water. The function of eliminating the inconvenience of supplying poor quality makeup water to the cooling water circulation system due to the stagnation of water is obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a system configuration diagram showing a water treatment system of a fuel cell power generator according to an embodiment of the present invention. The same components as those in the prior art are denoted by the same reference numerals, and redundant description will be omitted. In the figure, an ion-exchange type water treatment apparatus 31 discharges a main ion-exchange resin cylinder 32 arranged on the inlet valve 18 side of the mixed water 8 and a make-up water 9 of low electric conductivity which is connected in series at a subsequent stage. A small-capacity auxiliary ion-exchange resin tube 33 and an electric conductivity sensor 34 connected to the upstream side of the auxiliary ion-exchange resin tube as electric conductivity monitoring means.
And 1 μS for example by the electric conductivity sensor-34.
Make-up water 9 controlled to a low electrical conductivity of not more than / cm
Is supplied to the cooling water circulation system 10 of the fuel cell 1 via the
The ion-exchange type water treatment apparatus 31 is connected to the auxiliary water tank 12 containing the mixed water 8 via the inlet valve 18, the cooler 14, and the pump 13, and constitutes a water treatment system as a whole.

The main ion-exchange resin tube 32 continuously performs the ion-exchange treatment of the mixed water 8 during the operation of the ion-exchange type water treatment apparatus.
9 is filled with an amount capable of discharging make-up water 9 having a low electric conductivity of, for example, 1 μS / cm or less during a predetermined replacement cycle. On the other hand, the auxiliary ion exchange resin cylinder 33 is provided with an electric conductivity sensor.
34 is responsible for the ion exchange processing of the mixed water 8 from the time when the main ion exchange resin cylinder 32 reaches the end of its life to the time when the exchange work of the ion exchange resin 39 is completed. The filling amount is limited to an amount that can maintain the ion exchange function for a few days by adding the number of days for waiting for the exchange of the ion exchange resin, for example, the number of days of non-conductivity monitoring such as holidays. be able to. The number of the main ion exchange resin cylinders 32 may be reduced to one, or the number may be reduced to an arbitrary size to increase the degree of integration and save space. However, in this case, one conductivity sensor 34 is provided on the upstream side of the auxiliary ion exchange resin cylinder 33 regardless of the number of divisions of the main ion exchange resin cylinder, and the conductivity sensor 34 is provided for the last divided ion exchange resin cylinder of the main ion exchange resin cylinder. You only have to monitor the lifetime,
Thereby, the configuration of the ion-exchange type water treatment apparatus can be simplified.

In the ion-exchange type water treatment apparatus constructed as described above, the service life of the main ion-exchange resin tube 32 is detected by the conductivity sensor 34, and the exchange work of the ion-exchange resin is arranged. Since the auxiliary ion exchange resin cylinder 33 is in charge of the ion exchange operation for several days from the time to the start of the exchange operation, during this time, the low-conductivity make-up water 9 can be continuously supplied to the cooling water circulation system 10. Also,
The replacement work of the ion-exchange resin 39 is performed by the main ion-exchange resin cylinder,
By performing it together with the auxiliary ion exchange resin cylinder,
The auxiliary ion exchange resin cylinder is again in a standby state for ion exchange resin exchange, but since the amount of ion exchange resin filled in the auxiliary ion exchange resin cylinder is limited to an amount corresponding to the number of days to wait for ion exchange resin exchange, There is little waste from replacement,
The ion exchange capacity of the ion exchange resin can be effectively utilized.

FIG. 2 is a system configuration diagram showing an ion-exchange type water treatment apparatus according to another embodiment of the present invention. The present embodiment is different from the above-described embodiment in that the exchange resin tube 32 or the auxiliary ion exchange resin tube 33 is arbitrarily selected and a bypass pipe 41 is provided to enable refilling of the ion exchange resin 39. The bypass pipe passage 41 has a three-way switching valve 43 for switching the mixed water 8 between the main ion exchange resin cylinder 32 side and the bypass pipe 42 side, and the discharge of makeup water 9 between the bypass pipe 42 side and the auxiliary ion exchange resin cylinder 33 side. , A pair of stop valves 45 and 46 connected in series between the main ion exchange resin tube and the auxiliary ion exchange resin tube, an intermediate point between the pair of stop valves, and the bypass pipe 42. The conductivity sensor -34 is connected to the upstream side of the stop valve 45.

The bypass piping 41 constructed as described above
During normal operation, the three-way switching valves 43 and 44 are switched to the ion-exchange resin cylinder side and the stop valves 45 and 46 are opened during the normal operation, so that the mixed water 8 is supplied to the main ion-exchange resin cylinder 32. Alternatively, ion exchange processing is performed in the auxiliary ion exchange resin cylinder 33. When replacing the ion exchange resin in the main ion exchange resin cylinder, the mixed water passes through the bypass pipe 42 and the branch pipe 47 by switching the three-way switching valve 43 to the bypass pipe 42 side and closing the stop valve 45. The auxiliary ion-exchange resin tube 33 performs ion exchange processing, and the makeup water 9 can be supplied to the cooling water circulation system 10 through the three-way switching valve 44.
During this time, the ion exchange resin in the main ion exchange resin cylinder can be exchanged.

Further, the exchange of the ion exchange resin in the auxiliary ion exchange resin cylinder 33 is performed by closing the stop valve 46 and setting the three-way switching valve 44 to the bypass pipe 42 side.
Is purified by the main ion exchange resin tube 32 and supplied to the cooling water circulation system 10 through the branch pipe 47, the bypass pipe 42, and the three-way switching valve 44, during which the ion exchange resin in the auxiliary ion exchange resin cylinder 33 is exchanged. can do. Also, the bypass pipe 41 has no ion exchange resin cylinder,
In addition, since the supply water flows even during the replacement work, there is no stagnation of the water, and the inconvenience of supplying poor quality water to the cooling water circulation system can be eliminated.

[0022]

As described above, according to the present invention, the ion-exchange type water treatment apparatus for a fuel cell power generator includes a main ion-exchange resin cylinder, an auxiliary ion-exchange resin cylinder connected in series at a subsequent stage, and the main ion-exchange resin cylinder. The auxiliary ion exchange resin cylinder comprises an electric conductivity monitoring means provided between the ion exchange resin cylinder and the auxiliary ion exchange resin cylinder. After detecting that the amount of ion exchange resin has exceeded the set value, the period until the resin exchange of the main ion exchange resin cylinder is completed is to be filled with an amount of ion exchange resin capable of discharging make-up water having an electric conductivity equal to or less than the set value. . As a result, it is possible to prevent a situation in which supply water having high conductivity is supplied to the cooling water circulation system due to a delay in replacement time and a liquid junction is caused. It is possible to provide a water treatment system capable of minimizing the residual use of the fuel cell, thereby reducing the running cost of the fuel cell power generator.

The main ion-exchange resin cylinder can be filled with an ion-exchange resin in an amount corresponding to a predetermined life period into one ion-exchange resin cylinder, and only one conductivity sensor is required. It is possible to provide a water treatment system in which the configuration of the water treatment device can be simplified, the installation space thereof can be reduced, and the initial cost of the fuel cell power generator can be reduced.

Further, the ion-exchange type water treatment apparatus is capable of arbitrarily selecting a main ion-exchange resin cylinder or an auxiliary ion-exchange resin cylinder without stopping the supply of make-up water, and a bypass for refilling the ion-exchange resin. By providing a bypass, particularly a bypass pipe without a spare ion-exchange resin cylinder, the ion-exchange resin can be exchanged efficiently without stopping the supply of make-up water. In addition, it is possible to eliminate the inconvenience that water is stagnated in the spare ion exchange resin cylinder and poor quality makeup water is supplied to the cooling water circulation system, and therefore, there is an advantage that wasteful consumption of power due to a liquid junction can be almost completely prevented. Can be

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fuel cell power generation device according to an embodiment of the present invention.

FIG. 2 is a system configuration diagram showing an ion-exchange type water treatment apparatus according to a different embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional water-cooled fuel cell power generator.

FIG. 4 is a system configuration diagram showing a conventional ion-exchange type water treatment apparatus.

FIG. 5 is a system configuration diagram showing a different conventional ion exchange type water treatment apparatus.

FIG. 6 is a system configuration diagram showing another conventional ion-exchange type water treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell 1G Air off-gas 2 Fuel reformer 2G Combustion exhaust gas 3 Cooling plate 4 Steam separator 5 Condenser condenser 6 Cooling water 7 Condensed water 8 Mixed water 9 Makeup water 10 Cooling water circulation system 11 Water treatment system 12 Auxiliary water tank DESCRIPTION OF SYMBOLS 15 Ion exchange type water treatment apparatus 16 Ion exchange resin cylinder 17 Conductivity sensor 21 Bypass piping 31 Ion exchange type water treatment apparatus 32 Main ion exchange resin cylinder 33 Auxiliary ion exchange resin cylinder 34 Electric conductivity monitoring means (Conductivity sensor −) 39 Ion exchange resin 41 Bypass piping 42 Bypass pipe 43 Three-way switching valve 44 Three-way switching valve 45 Stop valve 46 Stop valve 47 Branch pipe

Claims (3)

(57) [Claims] (1) Tap water is mixed with condensate obtained by condensing water vapor in an air off-gas of a fuel cell and combustion exhaust gas of a fuel reformer, and the mixed water is passed through an ion-exchange type water treatment apparatus to obtain low electric conductivity. In the fuel cell power generator for replenishing the fuel cell or the fuel reformer as a replenishing water, the ion-exchange type water treatment device comprises: a main ion-exchange resin tube; and an auxiliary ion-exchanger connected in series at a subsequent stage. A resin cylinder, and electrical conductivity monitoring means provided between the main ion exchange resin cylinder and the auxiliary ion exchange resin cylinder, wherein the auxiliary ion exchange resin cylinder comprises The period from when the conductivity is detected to exceed the set value to when the resin exchange of the main ion exchange resin cylinder is completed,
A fuel cell power generator comprising an amount of ion exchange resin capable of discharging make-up water having an electric conductivity equal to or less than the set value. 2. The ion-exchange type water treatment apparatus can arbitrarily select a main ion-exchange resin cylinder or an auxiliary ion-exchange resin cylinder without stopping discharge of make-up water, thereby enabling refilling of ion-exchange resin. The fuel cell power generator according to claim 1, further comprising a bypass pipe line. 3. The three-way switching valve for switching the mixed water between the main ion exchange resin cylinder side and the bypass pipe side, and discharging the makeup water to the bypass pipe side and the auxiliary ion exchange resin cylinder side. A three-way switching valve for switching, a pair of stop valves connected in series between the main ion exchange resin cylinder and the auxiliary ion exchange resin cylinder, and a branch pipe communicating with an intermediate point between the pair of stop valves and the bypass pipe. 3. The fuel cell power generator according to claim 2, wherein electric conductivity monitoring means is provided on the main ion exchange resin cylinder side of the pair of stop valves.