JP2008248851A - Flow rate control method and device for pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate risk of sudden change of flow rate and unstable flow rate control. <P>SOLUTION: A fuel pressurizing pump is formed by connecting four small capacity pumps in parallel. When a second small capacity pump, a third small capacity pump, and fourth small capacity pump are started in an order in addition to a first small capacity pump, according to increase of load demanded for the fuel pressurizing pump, the small capacity pump to be newly started is started at output of 40% of individual rated output which is in a range where stable flow rate control can be done. Simultaneously, output of the small capacity pump which has been operating is reduced by 40% of the individual rated output. Increment of start output of the small capacity pump to be newly started is absorbed by the output reduction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a pump used as a pump for boosting and supplying a reforming raw material to a fuel processing device in a fuel cell power generator, and a pump for supplying air to a CO selective oxidation reactor of the fuel processing device. The present invention relates to a flow rate control method and device for a pump device for enabling the flow rate of the device to be optimally controlled.

  A fuel cell is expected to be an effective power generation device because it has higher thermal efficiency and less environmental pollution than other power generation methods using fuel. In particular, the polymer electrolyte fuel cell (PEFC) generates power at a low temperature of 100 ° C. or less, and has a high output density. Therefore, the polymer electrolyte fuel cell (PEFC) can be downsized as compared with other types of fuel cells and can be easily started. In recent years, it has come to be used as a power generator for small-scale business use or home use.

A general configuration of a power generation device (PEFC power generation device) using the polymer electrolyte fuel cell is as follows. That is, as shown in FIG. 6, both surfaces of a solid polymer electrolyte membrane in which a fluorine-based ion exchange membrane is used as an electrolyte are sandwiched between both cathode (air electrode) 2 and anode (fuel electrode) 3 gas diffusion electrodes. The polymer electrolyte fuel cell 1 is formed by stacking the cells formed through a separator (not shown) as a stack. On the inlet side of the anode 3 in the polymer electrolyte fuel cell 1, a fuel processor 4 comprising a reformer 5, a low temperature shift converter 6, a CO selective oxidation reactor (CO remover) 7 in this order, and a humidification A vessel 8 is provided. As a result, the raw material for reforming (raw fuel) 9 such as city gas (natural gas) and LPG supplied from the fuel supply unit is desulfurized by the desulfurizer 10 and then the raw material preheater (raw fuel vaporizer). 11 is preheated and then supplied to the fuel processor 4 together with the steam 13 introduced from the water evaporator 12 and heated to about 700 ° C. by the reformer 5 of the fuel processor 4 to improve the steam. The quality is made to do. The resulting reformed gas (fuel gas) 14 is guided to the low-temperature shift converter 6 to be lowered to about 250 ° C. for a shift reaction, and further to about 150 ° C. in the CO selective oxidation reactor 7. To remove CO.
Thereafter, the reformed gas 14 delivered from the fuel processing device 4 is humidified by the humidifier 8 and then supplied to the anode 3 of the polymer electrolyte fuel cell 1. On the other hand, air 15 as an oxidizing gas is supplied to the inlet side of the cathode 2 through the humidifier 8 after being pressurized by the air blower 16.

  With this configuration, in the polymer electrolyte fuel cell 1, hydrogen in the reformed gas 14 supplied to the anode 3 side and oxygen in the air 15 supplied to the cathode 2 side are electrochemically converted. Reaction (fuel cell reaction) is performed, and the electromotive force generated at this time is taken out.

  After the fuel cell reaction by the polymer electrolyte fuel cell 1, unreacted hydrogen remains in the anode offgas 17 discharged from the outlet of the anode 3. For this purpose, the anode off-gas 17 is introduced into a burner (not shown) attached to the reformer 5 of the fuel processor 4 and burned, and steam reforming which is an endothermic reaction in the reforming chamber of the reformer 5. It is used as a heat source for advancing the quality reaction.

  Further, in view of the small calorific value of the anode off-gas 17, a part of the raw material 9 such as city gas and LPG supplied from the fuel supply unit is used as the fuel 9 a for the burner of the fuel processing device 4. By supplying and burning, when the fuel processor 4 is operated and steam reforming of the raw material 9 is performed in the reformer 5, the amount of heat that is insufficient with only the calorific value of the anode offgas 17 is compensated. It is. Reference numeral 18 denotes a cooling unit in the polymer electrolyte fuel cell 1 (see, for example, Patent Document 1).

  By the way, when the raw material 9 for reforming such as city gas or LPG is supplied to the reformer 5 of the fuel processor 4 in the polymer electrolyte fuel cell power generator, Since the catalyst is densely packed, the raw material 9 is pressurized to a required pressure with a fuel booster pump and then sent to the fuel processor 4.

  Further, the fuel boost pump has a minimum flow rate of the raw material 9 to be supplied to the fuel processor 4 in connection with the control of the output of the polymer electrolyte fuel cell 1 in the polymer electrolyte fuel cell power generator. Therefore, a very large turndown ratio that can be stably controlled even when the flow rate is set to a low flow rate of about 10% of the rated flow rate is required.

  In addition, it is necessary to supply oxygen to the CO selective oxidation reactor 7 of the fuel processing apparatus 4 in the fuel cell power generation apparatus in order to selectively oxidize CO in the reformed gas 14 that is excessive in hydrogen. As an oxygen supply source, air is supplied to the required pressure by using an air pump. The air pump for the CO selective oxidation reactor 7 is required to have a turndown ratio that can set the minimum flow rate to about 50% of the rated flow rate in connection with the output control of the polymer electrolyte fuel cell 1. In addition, accurate flow rate control is required under high pressure conditions.

  In addition, in an apparatus having a configuration in which a plurality of pumps having a required capacity are connected in parallel, the pump is operated among the plurality of pumps connected in parallel according to an increase or decrease in required load (pump flow rate). Conventionally, a technique has been proposed in which the flow rate according to the required load can be obtained from the total flow rate of the pumps in operation by appropriately increasing or decreasing the number of pumps (for example, Patent Document 2, (See Patent Document 3).

JP 2005-127634 A JP-A-8-261190 JP 7-332280 A

  However, in general, it is difficult for the pump to perform stable flow control at 30 to 35% or less of the rated output. In general, when the pump output is gradually increased at the time of starting the pump, the flow rate tends to suddenly rise from the state of zero flow rate to the required flow rate at a certain point in time. On the contrary, when the output of the pump is gradually reduced, the flow rate suddenly decreases from the required flow rate to the flow rate 0 when the output is reduced to some extent. For this reason, it is difficult to continuously increase or decrease the flow rate of the pump around the flow rate of zero.

  Therefore, a very large turndown ratio that can be set to a low flow rate of about 10% of the rated flow rate as required for a fuel booster pump that supplies the raw material 9 to the fuel processing device 4 in the fuel cell power generator described above. Is difficult to obtain with a single pump.

  Further, as shown in Patent Document 2, the number of pumps to be operated is appropriately increased or decreased according to the increase or decrease in required load in an apparatus having a configuration in which a plurality of pumps are connected in parallel. By doing so, it is possible to change from the flow rate obtained by operating only one pump to the flow rate obtained as the sum of the flow rates when operating all the pumps, and achieve a very large turndown ratio. It will be possible. However, for each of the pumps connected in parallel, there is a problem that it is difficult to perform stable flow control at 30 to 35% or less of the rated output of each pump as described above, and at the time of starting and stopping There is a problem that a sudden change in flow rate tends to occur. Therefore, when a non-operating pump is newly activated in response to an increase in required load, the sum of the flow rates may change suddenly because the output of the newly activated pump suddenly rises to the required flow rate. Is concerned. Further, while the output of the newly activated pump is 30 to 35% or less of the rated output of the pump itself, the flow control of the newly activated pump becomes unstable. There is also a risk that the control of the sum of the flow rates may be destabilized. On the other hand, when one of the pumps in operation is stopped in response to a reduction in the required load, the flow rate of the pump is changed from the required flow rate to a point when the output of the pump to be stopped is reduced to some extent. There is a concern that the total flow rate may change suddenly as it suddenly drops to zero. In addition, when the output of the pump is reduced to a range of 30 to 35% or less of the rated output of the pump, the flow control becomes unstable, so the control of the total flow is also unstable. There is a fear.

  In addition, what was described in patent document 3 is the relationship between the discharge amount of each pump, an actual head, and electric power used when controlling the operation | movement of the several pump connected in parallel and controlling the sum total of flow volume. The number of pumps to be operated and the combination of individual pump outputs were determined so that the total amount of power used was minimized when the head and flow rate required for the entire pump were achieved. Therefore, it is possible to solve the problem that the sum of the flow rates may change suddenly under the influence of a sudden change in flow rate that occurs at the time of starting and stopping of each pump, or the output of a certain pump There is no idea about the idea to solve the problem that the control of the total flow rate becomes unstable due to the fact that the flow rate is 30 to 35% or less of the rated output and the stable flow rate control cannot be performed. No.

  Therefore, the present invention performs optimal flow rate control according to increase / decrease in the required load, using a pump device configured by connecting a plurality of pumps having a smaller rating than the required load in parallel. In addition, even when some pumps are started or stopped according to the increase or decrease in the required load, there is a sudden change in the total flow rate or instability in the control of the total flow rate. It is an object of the present invention to provide a flow rate control method and apparatus for a pump device that can eliminate the possibility of occurrence.

  In order to solve the above problems, the present invention comprises a plurality of pumps connected in parallel, and the number of operating pumps and the output of the operating pumps are appropriately increased or decreased according to the required increase or decrease of the load. When a new pump is started in addition to a pump that is already operating in response to an increase in the required load in a certain pump device, the newly started pump is stabilized in the pump. A pump device that is activated to start up at a required output that is an output region in which flow rate control is possible, and at the same time, the output of the pump that is already in operation is reduced by an amount corresponding to the output that is started up by the newly started pump. A flow rate control method, a pump device in which a plurality of pumps are connected in parallel, and a controller are provided, and the controller is connected to the pump device according to a required increase or decrease in load. When the number of pumps in operation and the output of the pumps in operation are increased or decreased as appropriate, and when a new pump is started in addition to the pump that is already in operation in response to an increase in the required load, The pump to be started is started to start up at a required output that is an output region in which stable flow rate control is possible in the pump, and at the same time, the output of the pump that is already in operation corresponds to the output that is started up by the pump that is newly started The flow rate control device of the pump device is configured to have a function of issuing a command to reduce the amount.

  In addition, in the pump device in which the on / off control type pump and the variable flow rate type pump are connected in parallel, the on / off control type pump is always operated, the required load, and the on / off control type. A flow rate control method for the pump device that controls the output of the variable flow rate pump according to the difference from the flow rate obtained by the operation of the off control type pump, and a variable with the on / off control type pump A pump apparatus comprising a flow rate type pump connected in parallel and a controller are provided. The controller is always operated with the on / off control type pump, the required load, and the on / off control. The flow rate control device of the pump device is configured to have a function of controlling the output of the variable flow rate type pump according to the difference from the flow rate obtained by the operation of the type pump.

According to the present invention, the following excellent effects are exhibited.
(1) In a pump device in which a plurality of pumps are connected in parallel, and the number of operating pumps and the output of the operating pumps are appropriately increased or decreased according to the increase or decrease in required load. When a new pump is started in addition to a pump that is already in operation in response to an increase in required load, the newly started pump becomes an output region in which stable flow control in the pump is possible Since it is activated to start up with the required output, and at the same time, it is a flow rate control method and apparatus for a pump device that reduces the output of the pump that is already in operation by an amount corresponding to the output that starts up with the newly activated pump. The increase in output by the newly activated pump can be absorbed by the decrease in the output of the pump that is already in operation. For this reason, it is possible to prevent the risk that the flow rate in the entire pump device suddenly changes before and after the time when the pump is newly started. In addition, since the pump to be newly activated is started up with an output capable of controlling the stable flow rate, it is possible to prevent the possibility that the flow rate control becomes unstable when the pump is newly activated. . Therefore, in the pump apparatus as a whole, the flow rate can be changed smoothly according to the required load change.
(2) By combining a plurality of pumps having a small turndown ratio, it is possible to construct a pump device that can obtain a very large turndown ratio as a whole.
(3) In the pump device in which the on / off control type pump and the variable flow rate type pump are connected in parallel, the on / off control type pump is always operated, and the required load, The load required by using the flow control method and device of the pump device that controls the output of the variable flow pump according to the difference from the flow obtained by the operation of the on / off control pump. Compared to the above, a variable flow rate pump that does not have a sufficient flow rate with a single pump unit that combines an on / off control type pump with the required output with a flow rate that satisfies the required load. Can be controlled.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIGS. 1 (a), (b), (c), (d), (e), and FIG. 2 show fuel having the same configuration as that shown in FIG. 6 as one embodiment of the flow rate control method and apparatus for the pump device of the present invention. This shows a case where the present invention is applied to a fuel booster pump 19 for supplying a reforming raw material 9 (see FIG. 6) to a fuel processing device 4 in a battery power generation device, and has the following configuration.

That is, the fuel booster pump 19 as the pump device in the present embodiment has a rated output and a rated flow (required for the fuel booster pump 19 to cope with a required load as shown in FIG. Hereinafter, a small number of small capacity pumps 20a, 20b, 20c, and 20d having a smaller output than the total rated output and the total rated flow) are connected in parallel.
Further, each of the small capacity pumps 20a, 20b, 20c, and 20d has a rated output (hereinafter referred to as an individual rated output) of one unit as shown in FIGS. 1 (a), (b), (c), and (d). By operating the small capacity pumps 20a, 20b, 20c, and 20d at an output capable of stably controlling the flow rate, that is, an output in a region that does not fall within 30 to 35% of the individual rated output, the fuel boost pump 19 as a whole is operated. Is set to achieve the desired minimum flow rate. Specifically, when the minimum flow rate desired for the fuel booster pump 19 is 10% of the total rated flow rate, for example, the individual rated output of each of the small capacity pumps 20a, 20b, 20c, and 20d is used as the fuel. What is necessary is just to respectively set so that it may become 25% of the said total rated output of the pressure | voltage rise pump 19. Thus, the output when one small capacity pump 20a, 20b, 20c, 20d is operated at 40% of the individual rated output corresponds to the output of 10% of the total rated output of the fuel boost pump 19. It is.

  The number of small capacity pumps 20a, 20b, 20c and 20d connected in parallel is the sum of the flow rates obtained when all the small capacity pumps 20a, 20b, 20c and 20d are operated at individual rated flow rates. It is set to satisfy the total rated flow rate of the fuel booster pump 19. Specifically, in view of the fact that the individual rated output of each small capacity pump 20a, 20b, 20c, 20d is set to be 25% of the total rated output of the fuel boost pump 19 as described above. The number of units to be connected may be four. Thus, the total rated flow rate of the fuel boost pump 19 can be satisfied by the sum of the individual rated flow rates of the small capacity pumps 20a, 20b, 20c, and 20d. In this specification, for convenience of explanation, it is assumed that each pump can be operated at a flow rate corresponding to the output rate, assuming that internal loss can be ignored.

  Further, a controller 21 is provided for giving commands to the small-capacity pumps 20a, 20b, 20c, and 20d in accordance with changes in the load required for the fuel boost pump 19.

  Specifically, the controller 21 determines that the load required for the fuel boost pump 19 is between 0 and 25% of the total rated output of the fuel boost pump 19, as shown in FIG. A command is given only to the first small-capacity pump 20a, and the output of the first small-capacity pump 20a is increased according to the required increase amount of the load. At this time, when starting the first small-capacity pump 20a from the state of zero flow rate, if the output is gradually increased, a required value is obtained at a certain time, for example, when the output becomes 5% of the total rated output. When the flow rate suddenly rises and the output of the first small capacity pump 20a is 30 to 35% or less of the individual rated output, the flow control in the first small capacity pump 20a becomes unstable. there is a possibility. However, the minimum flow rate required for the fuel booster pump 19 as a whole is 10% of the total rated flow rate, which means that the first small capacity pump 20a has an output of 40% of the individual rated output. Therefore, even in the vicinity of this flow rate, it is possible to control the flow rate stably by the first small capacity pump 20a. As described above, as shown in FIG. 1 (e), the actual flow rate of the fuel boost pump 19 can be satisfactorily controlled according to the required load in the range of about 10% to 25% of the total rated flow rate. It becomes like this.

  Next, when the load required for the fuel boost pump 19 reaches 25% of the total rated output, the first small capacity pump 20a reaches the individual rated output. Therefore, when the load required for the fuel boost pump 19 exceeds 25% of the total rated output, the controller 21 issues a command to the second small capacity pump 20b as shown in FIG. Then, the second small-capacity pump 20b is started up and started at a stretch to an output in a region where stable flow rate control is possible, for example, 40% of the individual rated output. Further, simultaneously with the activation of the second small-capacity pump 20b, the controller 21 performs the first small-capacity pump 20a, which is a small-capacity pump already in operation at that time, as shown in FIG. Is temporarily reduced by an amount corresponding to the output rising when the second small capacity pump 20b is started, that is, 40% of the individual rated output. As a result, the output of the first small-capacity pump 20a is reduced to 60% of the individual rated output, so that the output of the second small-capacity pump 20b is reduced by the decrease in the output of the first small-capacity pump 20a. The increase in output accompanying startup is absorbed. Therefore, even when the second small-capacity pump 20b is started, there is no possibility that a sudden change occurs in the overall flow rate of the fuel boost pump 19.

  After that, while the load required for the fuel boost pump 19 is 25 to 35% of the total rated output, the controller 21 performs the second small-capacity pump as shown in FIGS. The output of the first small-capacity pump 20a in which the output is temporarily reduced to 60% of the individual rated output when the second small-capacity pump 20b is started up while maintaining the output of 20b at 40% of the individual rated output. Is increased in accordance with the required increase in load. Further, when the load required for the fuel boost pump 19 reaches 35% of the total rated output, the output of the first small capacity pump 20a reaches the individual rated output again. Therefore, the controller 21 keeps the output of the first small capacity pump 20a at the individual rated output while the load required for the fuel boost pump 19 is 35 to 50% of the total rated output. The output of the second small capacity pump 20b is increased according to the required increase amount of the load. As described above, as shown in FIG. 1 (e), the actual flow rate of the fuel boost pump 19 is calculated by the sum of the flow rates of the first and second small capacity pumps 20a and 20b in which the flow rate control is stably performed. It becomes possible to satisfactorily control according to the required load in the region of 25 to 50% of the rated flow rate.

  Next, when the load required for the fuel booster pump 19 reaches 50% of the total rated output, the second small-capacity pump 20b also reaches the individual rated output following the first small-capacity pump 20a. become. Therefore, when the load required for the fuel boost pump 19 exceeds 50% of the total rated output, the controller 21 sends the third small capacity pump 20c to the third small capacity pump 20c as shown in FIG. A command is issued in the same manner as when the second small-capacity pump 20b is started, and the third small-capacity pump 20b is started up to 40% of the individual rated output capable of stable flow rate control and started. At the same time, the controller 21 outputs, for example, the output of the second small-capacity pump 20b among the small-capacity pumps 20a and 20b already operating at that time, as shown in FIG. Is once reduced by 40%. As a result, the output of the second small-capacity pump 20b is reduced to 60% of the individual rated output, and the third small-capacity pump 20c is activated by the decrease in the output of the second small-capacity pump 20b. The accompanying increase in output is absorbed. Therefore, even when the third small-capacity pump 20c is started, there is no possibility that a sudden change occurs in the overall flow rate of the fuel boost pump 19.

  After that, while the load required for the fuel boost pump 19 is 50 to 60% of the total rated output, the controller 21 performs the first operation as shown in FIGS. While the small-capacity pump 20a is maintained at the individual rated output and the output of the third small-capacity pump 20c is held at 40% of the individual rated output, the output is temporarily output when the third small-capacity pump 20b is started. The reduced output of the second small-capacity pump 20b is increased in accordance with the required increase in load. Further, when the load required for the fuel boost pump 19 reaches 60% of the total rated output, the output of the second small capacity pump 20b reaches the individual rated output again. For this reason, the controller 21 individually outputs the outputs of the first and second small capacity pumps 20a and 20b while the load required for the entire fuel boost pump 19 is 60 to 75% of the total rated output. While maintaining the rated output, the output of the third small capacity pump 20c is increased according to the required increase in load. As described above, as shown in FIG. 1 (e), the sum of the flow rates of the first, second, and third small-capacity pumps 20a, 20b, and 20c, in which the flow rate control is stably performed, The actual flow rate can be satisfactorily controlled according to the required load in the region of 50 to 75% of the total rated flow rate.

  Furthermore, when the load required for the fuel boost pump 19 as a whole reaches 75% of the total rated output, the third small-capacity pump 20c follows the first and second small-capacity pumps 20a and 20b. It reaches the rated output. For this reason, when the load required for the fuel boost pump 19 as a whole exceeds 75% of the total rated output, the controller 21 sends the fourth small capacity pump 20d to the fourth small capacity pump 20d as shown in FIG. A command is issued in the same manner as when the second and third small-capacity pumps 20b and 20c are started, and the fourth small-capacity pump 20d is blown up to 40% of the individual rated output capable of stable flow control. Get up and running. At the same time, the controller 21 individually outputs, for example, the output of the third small-capacity pump 20c among the small-capacity pumps 20a, 20b, and 20c that are already in operation as shown in FIG. Reduce by 40% of the rated output. As a result, the output of the third small-capacity pump 20c is reduced to 60% of the individual rated output, and the increase in the output accompanying the start-up of the fourth small-capacity pump 20d is absorbed by the decrease in the output. Therefore, even when the fourth small-capacity pump 20d is started, there is no possibility that a sudden change occurs in the overall flow rate of the fuel boost pump 19.

  Thereafter, while the load required for the fuel booster pump 19 is 75 to 85% of the total rated output, the controller 21 performs the above operation as shown in FIGS. 1 (a), (b), (c) and (d). While the first and second small capacity pumps 20a and 20b are held at the individual rated output, and the output of the fourth small capacity pump 20d is held at 40% of the individual rated output, the fourth small capacity pump The output of the third small-capacity pump 20c, whose output is temporarily reduced when the pump 20d is started, is increased according to the required increase amount of the load. Thereafter, when the load required for the fuel boost pump 19 reaches 85% of the total rated output, the output of the third small-capacity pump 20c reaches the individual rated output again. Therefore, the controller 21 controls the first, second, and third small capacity pumps 20a, 20b, and 20c while the load required for the fuel boost pump 19 is 85 to 100% of the total rated output. The output of the fourth small-capacity pump 20d is increased according to the required increase amount of the load while maintaining the output at the individual rated output. As described above, as shown in FIG. 1 (e), the actual flow rate of the fuel booster pump 19 is set to the total rating based on the sum of the flow rates of the small capacity pumps 20a, 20b, 20c, and 20d. In the region of 75 to 100% of the flow rate, it becomes possible to control well according to the required load.

  When the load required for the fuel boost pump 19 decreases from 100% to 10% of the total rated output, the small-capacity pumps 20d, 20c are reversely operated in the procedure reverse to that when the required load increases. , 20b, and 20a are sequentially reduced, and the small-capacity pumps 20a, 20b, 20c, and 20d that have been reduced in output are sequentially stopped so that the number of operating pumps is sequentially reduced. Good. In this way, when the pumps 20d, 20c, and 20b are stopped in order, each pump 20d, 20c, and 20b can be stopped at once from a state where stable flow control is possible as an output of 40% of the individual rated output. There is no possibility that the control of the overall flow rate of the fuel boost pump 19 will become unstable due to the decrease in the output of the pumps 20d, 20c, 20b. Further, when each of the small capacity pumps 20d, 20c and 20b is stopped from the output state of 40% of the individual rated output, one of the small capacity pumps 20c, 20b and 20a in operation is one small capacity pump 20c, 20b, The output is reduced until the output state of 20a reaches 60% of the individual rated output in advance, and the small-capacity pump 20c in which the output is reduced in advance at the same time when the small-capacity pumps 20d, 20c, and 20b are stopped. , 20b, 20a can be recovered to 100% of the individual rated output, and the overall flow rate of the fuel boost pump 19 may suddenly change before and after the small capacity pumps 20d, 20c, 20b are stopped. Prevented in advance.

  2 that are the same as those shown in FIG. 6 are denoted by the same reference numerals.

  As described above, according to the flow rate control method and apparatus of the pump device of the present invention, by controlling the small capacity pumps 20a, 20b, 20c, and 20d as described above, The flow rate can be controlled satisfactorily. Moreover, the small capacity pumps 20a, 20b, 20c, and 20d may cause instability in flow control in the region of 30 to 35% or less of the individual rated output of the pump alone, or sudden flow changes at start and stop Even if the pump characteristic is such that the flow rate of the fuel booster pump 19 as a whole can be changed smoothly according to the required load change, as shown in FIG.

  Further, the fuel boost pump 19 can perform stable flow rate control even at a low flow rate of about 10% of the total rated flow rate. Therefore, by combining the small capacity pumps 20a, 20b, 20c, and 20d having a small turndown ratio, it is possible to function as the fuel boost pump 19 that can obtain a very large turndown ratio as a whole.

  In the above, when the new small-capacity pumps 20b, 20c, and 20d are sequentially started in addition to the small-capacity pump 20a that is already in operation as the load required for the fuel booster pump 19 increases, the new start-up is started. The small output pumps 20b, 20c, and 20d have been explained as absorbing the increased output of the small-capacity pumps 20a, 20b, and 20c activated last time. (B) (c) (d) As shown in (e), when starting the third and fourth small capacity pumps 20c and 20d, by reducing the output of the first small capacity pump 20a, When the new small-capacity pumps 20b, 20c, and 20d are started, such as by absorbing the increase in output at the time of starting the third and fourth small-capacity pumps 20c and 20d, respectively. Small volume pump 20a has a middle, 20b, of the 20c, it may be reduce any output.

  Next, FIGS. 4 and 5 show another embodiment of the present invention. As a pump device to be a flow rate control target, the fuel processing device 4 in the fuel cell power generation device having the same configuration as shown in FIG. This shows a case where the present invention is applied to an air pump 22 for supplying air 26 to a CO selective oxidation reactor 7 (see FIG. 6), and has the following configuration.

  That is, as shown in FIG. 5, the air pump 22 as a pump device has a maximum flow rate with respect to a rated output and a rated flow rate required for the entire air pump 22 (hereinafter referred to as a total rated output and a total rated flow rate). The variable flow rate pump 23 having a total rated flow rate ratio of 75% and the on / off control pump 24 having a maximum flow rate of 25% compared to the total rated flow rate are connected in parallel.

  In addition, the variable flow pump 23 and a controller 25 for giving a command to the on / off control pump 24 according to the load required for the entire air pump 22 are provided.

  The control contents of the controller 25 will be described in detail. The controller 25 considers that the minimum flow rate required for the air pump 22 for the CO selective oxidation reactor 7 is about 50% of the total rated flow rate. When the air pump 22 is required to have a required load of 50 to 100% of the total rated flow rate in accordance with the ratio of the fuel cell output, as shown by the line a in FIG. The pump 24 is always started, and the flow rate variable flow rate pump 23 is changed according to the difference between the required load and the flow rate of 25% of the total rated flow rate obtained from the on / off control pump 24. A command is given. As a result, as shown by a line b in FIG. 4, a flow rate of 25% of the total rated flow rate is always obtained from the on / off control pump 24, and as shown by a line c in FIG. From this, a flow rate obtained by subtracting a flow rate corresponding to 25% of the total rated flow rate from the required load can be obtained. Therefore, depending on the sum of the flow rates of the variable flow pump 23 and the on / off control pump 24, A flow rate suitable for the required load can be obtained.

  As described above, according to the present embodiment as well, the above-mentioned CO selection is achieved as a whole by combining the variable flow pump 23 whose flow rate is insufficient with a single unit as compared with the required load with the ON / OFF control pump 24 having a small output. It becomes possible to obtain a flow rate that satisfies the load required for the air pump 22 for the oxidation reactor 7.

  Note that the present invention is not limited to the above-described embodiment. In the embodiment shown in FIGS. 1 (a), (b), (c), (d), (e), and FIG. The capacity pumps 20a, 20b, 20c, and 20d are connected in parallel, and the small capacity pumps 20a, 20b, 20c, and 20d are set so that the individual rated output is 25% of the total rated output of the fuel booster pump 19. The minimum flow rate required for a pump device formed by connecting a plurality of small-capacity pumps in parallel is an output region where stable flow control can be performed with one small-capacity pump. From the relationship between the minimum flow rate required for the pump device and the output area where stable flow rate control is possible with one small capacity pump, the individual small capacity pumps Appropriate rated output and capacity Constant and may be. Furthermore, since the ratio of the output and the ratio of the actual flow rate do not always match due to internal loss in an actual pump, the rated output and capacity of each of the small capacity pumps should be set appropriately in consideration of this internal loss. You can do it. Further, the number of the small-capacity pumps connected in parallel may be appropriately changed so that the required load can be satisfied by the sum of the flow rates of the small-capacity pumps. Therefore, two, three, or five or more may be connected in parallel.

  When the new small-capacity pumps 20b, 20c, and 20d are sequentially started in addition to the small-capacity pump 20a that is already in operation, the output for rapidly starting the small-capacity pumps 20b, 20c, and 20d is As long as it enters the output region in which stable flow rate control can be performed by the capacity pumps 20b, 20c, and 20d, it may be slightly increased or decreased from 40% of the individual rated output.

  Of course, various modifications can be made without departing from the scope of the present invention.

As an embodiment of the flow rate control method and apparatus of the pump device of the present invention, it shows a case where it is applied to a fuel boost pump. (A) (b) (c) (d) should constitute a fuel boost pump The figure which respectively shows control of the separate output of each small capacity | capacitance pump connected in parallel, (e) is a figure which shows the actual flow volume of a fuel pressure | voltage rise pump. It is a figure which shows the apparatus structure of the fuel pressure | voltage rise pump of FIG. FIG. 5 shows another example of control in the fuel booster pump of FIG. 1, wherein (a), (b), (c), and (d) indicate the individual outputs of the small capacity pumps connected in parallel to form the fuel booster pump. FIGS. 5A and 5B are diagrams showing the control, respectively, and FIG. 5E is a diagram showing the actual flow rate of the fuel boost pump. As another embodiment of the present invention, it shows a case where the present invention is applied to an air pump for a CO selective oxidation reactor, and shows a relationship between required loads and flow rates of an on / off control pump and a variable flow pump. It is. It is a figure which shows the apparatus structure of the air pump of FIG. It is a figure which shows the outline | summary of a general polymer electrolyte fuel cell power generator.

Explanation of symbols

19 Fuel boost pump (pump device)
20a, 20b, 20c, 20d Small capacity pump (pump)
21 Controller 23 Variable flow pump 24 On / off control pump 25 Controller

Claims (4)

  It is required in a pump device in which a plurality of pumps are connected in parallel and the number of operating pumps and the output of the pumps in operation are appropriately increased or decreased according to the increase or decrease in required load. When a new pump is started in addition to a pump that is already operating in response to an increase in load, the newly started pump has a required output that is an output region in which stable flow control in the pump is possible. A flow rate control method for a pump device, wherein the pump device is activated to start up, and at the same time, the output of the pump that is already in operation is reduced by an amount corresponding to the output of the pump that is newly started up.   In the pump device in which an on / off control type pump and a variable flow rate type pump are connected in parallel, the on / off control type pump is always operated, the required load, and the on / off status A flow rate control method for a pump device, characterized in that an output of the variable flow rate type pump is controlled according to a difference from a flow rate obtained by operation of a control type pump.   A pump device comprising a plurality of pumps connected in parallel and a controller, and the controller is operated according to the increase or decrease of the required load, the number of operating pumps in the pump device and the output of the pumps in operation When a new pump is started in addition to a pump that is already operating in response to an increase in required load, the newly started pump can be controlled with a stable flow rate. It has a function of starting up to start up with the required output that will be a proper output area, and at the same time issuing a command to reduce the output of the pump already in operation by an amount corresponding to the output of the pump that is newly started up A flow rate control device for a pump device, characterized in that it is configured.   A pump device comprising a parallel connection of an on / off control type pump and a variable flow rate type pump, and a controller. The controller is always required to operate the on / off control type pump. The pump device is characterized in that it has a function of controlling the output of the variable flow pump according to the difference between the load and the flow obtained by operating the on / off control pump. Flow control device.

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