JP2012204330A - Fuel cell power generation device and stopping method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generation device capable of draining while holding reformed gas suitable for a catalyst of a reformer in the reformer after stopping, and provide a stopping method of the fuel cell power generation device.SOLUTION: When stopping a fuel cell power generation device 1, a control unit 100 opens a water drain shutoff valve 39 of a reforming water evaporator and drains reforming water in the reforming water evaporator 11 in a state that at least a fuel cell anode inlet shutoff valve 35 and a fuel cell anode bypass line shutoff valve 37 are closed. After closing the water drain shutoff valve 39 of the reforming water evaporator, the control unit supplies a certain amount of reforming water to a reformer 2 and controls so that a pressure value measured by a pressure gauge 29 of a process line condensed heat exchanger lies within a certain range by controlling at least a reformer inlet shutoff valve 32, the fuel cell anode inlet shutoff valve 35 or the fuel cell anode bypass line shutoff valve 37.

Description

  Embodiments described herein relate generally to a fuel cell power generator and a method for stopping the same.

  A fuel cell power generator is a system that converts hydrogen generated by a reformer directly into electrical energy in a fuel cell body. Since this system is a power generation based on a chemical reaction, the power generation efficiency is high, the discharge of pollutants and noise is small, and it is evaluated as a power generation apparatus excellent in environmental performance.

  The reformer has a reforming unit with a reforming catalyst layer, and generates reformed gas containing hydrogen by a reforming reaction between hydrocarbon fuel or the like and steam generated by a reforming water evaporator. . Since the reforming reaction is an endothermic reaction at a high temperature, it is necessary to raise the temperature of the reforming catalyst layer to the operating temperature during startup, and it is necessary to continue heating the reforming catalyst layer during operation. Therefore, the reformer generally includes a burner and a burner combustion space, and supplies heat to the reforming catalyst during start-up and operation by burning combustible gas.

  Moreover, since the reformed gas derived from the reforming unit contains high concentration of carbon monoxide, the carbon monoxide concentration is lowered by the shift reactor. Downstream of the shift reactor, further oxidation with PROX (CO selective oxidation reactor) with PROX air or methane from carbon monoxide and hydrogen in the methanation reactor. The carbon concentration can also be reduced.

  In addition, if the hydrocarbon fuel introduced into the reforming section contains sulfur, the reforming catalyst deteriorates. Therefore, a desulfurizer is provided at the reforming section inlet, and a catalyst suitable for the presence of hydrogen is applied to this. If this is the case, recycle the reformed gas from a position upstream from the position where PROX air is introduced to a position upstream from the desulfurizer, and install a process line condensing heat exchanger so that the recycling flow path is not blocked by condensed water. We are trying to prepare for the upstream of the recycling line.

  The reformed gas derived from the reformer consumes hydrogen by power generation while passing through the fuel cell anode, and the anode off-gas containing the remaining hydrogen is burned by the burner. If there is too much water vapor in the anode off gas, it will be difficult for the burner to burn, so an anode off gas line condensing heat exchanger is provided to remove water vapor and water mist.

Japanese Patent No. 4130603 Japanese Patent No. 4175432 Japanese Patent No. 4098258

  In the reformer as described above, the steam purge is performed after the stop, and the steam purge is performed even at the start-up to prevent the air from flowing backward from the burner combustion space. However, the catalyst of the reactor applied to the reformer, particularly the copper zinc catalyst widely used in the shift reactor, deteriorates due to oxidation when exposed to water vapor. Some catalysts used in the reforming catalyst layer have a risk of being deteriorated by water vapor. For this reason, as the start / stop operation is repeated, the performance of the apparatus may deteriorate.

  The problem to be solved by the present invention is to provide a fuel cell power generator and a method for stopping the fuel cell power generator that removes moisture while holding the reformed gas suitable for the catalyst of the reformer in the reformer after the stop. is there.

  A fuel cell power generator according to an embodiment includes a reformed water evaporator that generates steam from reformed water, a reformed gas that includes hydrogen from hydrocarbons contained in fuel and steam generated by the reformed water evaporator. Included in reforming gas generated in the reforming device, reforming device inlet shut-off valve that shuts off and releases the fuel supplied to the inlet of the reforming device by opening and closing operation, and reforming gas generated in the reforming device Process line condensing heat exchanger for condensing water vapor, fuel cell anode consuming hydrogen contained in the reformed gas passing through the process line condensing heat exchanger, and reformed gas supplied to the inlet of the fuel cell anode A fuel cell anode inlet shut-off valve that shuts off and releases the fuel cell by an open / close operation, a fuel cell anode bypass line that bypasses the fuel cell anode from upstream to downstream, and the fuel cell anode A fuel cell anode bypass line shut-off valve that shuts off and releases the reformed gas through the mode bypass line by opening and closing operation, and discharge of reformed water from a branch upstream of the reformed water of the reformed water evaporator and its A fuel cell power generator comprising a reforming water evaporator drain-off valve that performs release by opening and closing operation, the process line condensing heat exchanger for measuring the pressure of the reformed gas in the vicinity of the process line condensing heat exchanger When stopping the pressure gauge and the fuel cell power generator, open the reformer water evaporator drain shutoff valve with at least the fuel cell anode inlet shutoff valve and the fuel cell anode bypass line shutoff valve closed. Discharging the reforming water from the reforming water evaporator and closing the reforming water evaporator water drain shutoff valve, and then supplying a certain amount of reforming water to the reforming device, at least the reforming device Entrance shut-off By controlling the fuel cell anode inlet shut-off valve or the fuel cell anode bypass line shut-off valve, the pressure value measured by the process line condensing heat exchanger pressure gauge is controlled to be within a certain range. And a control means.

  According to the present invention, it is possible to remove moisture while holding a reformed gas suitable for the catalyst of the reformer in the reformer after stopping.

The lineblock diagram showing an example of the composition of the fuel cell power generator concerning a 1st embodiment. The flowchart which shows an example of the stop procedure of the fuel cell electric power generating apparatus which concerns on the embodiment. The timing chart which shows an example of the stop procedure of the fuel cell electric power generating apparatus which concerns on the embodiment. The block diagram which shows an example of a structure of the fuel cell electric power generating apparatus which concerns on 2nd Embodiment. The block diagram which shows an example of a structure of the fuel cell electric power generating apparatus which concerns on 3rd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

(First embodiment)
A first embodiment will be described.

  FIG. 1 is a configuration diagram showing an example of the configuration of the fuel cell power generation device according to the first embodiment.

  A fuel cell power generator 1 shown in FIG. 1 includes a reformer 2, a fuel cell 3, a reformer 4, a desulfurizer 5, a fuel preheater 6, a shift reactor first stage 7, a shift reactor second stage 8, Process line condensing heat exchanger 9, PROX (CO selective oxidation reactor) 10, reforming water evaporator 11, water evaporator outlet pressure loss element 12, startup fuel pressure loss element 13, exhaust heat recovery device 14, ventilation fan 15 , Fuel inlet pressure gauge 16, reformer pressure gauge 17, fuel flow meter 18, burner air flow meter 19, fuel blower 21, burner air blower 22, cathode air blower 23, PROX air blower 24, reforming water pump 25, Anode off-gas line condensing heat exchanger 27, anode off-gas line condensate discharge device 28, process line condensing heat exchanger pressure gauge 29, fuel inlet shut-off valve 30, reformer inlet shut-off valve 32, burner fuel Shutoff valve 33, PROX air shutoff valve 34, fuel cell anode inlet shutoff valve 35, fuel cell anode outlet shutoff valve 36, fuel cell anode bypass line shutoff valve 37, fuel cell anode bypass line 37A, recycle line shutoff valve 38, recycle line 38A, the reforming water evaporator drain shutoff valve 39, the process line condensate drain device 40, the process line condensate drain device outlet shutoff valve 41, the control unit 100, and the like.

  The reformer 2 generates reformed gas containing hydrogen from hydrocarbons contained in the fuel and water vapor generated by the reformed water evaporator 11. The reformer 4, the desulfurizer 5, the fuel It includes a preheater 6, a shift reactor first stage 7, a shift reactor second stage 8, a PROX 10, a reforming water evaporator 11, and a water evaporator outlet pressure loss element 12.

  The fuel cell 3 includes a fuel cell anode 3a and a fuel cell cathode 3b.

  The reforming unit 4 includes a reforming catalyst layer 4a, a reforming unit burner 4b, and a burner combustion space 4c. While reformed fuel passes through the reforming catalyst layer 4a, heat transfer from the burner combustion space 4c The reforming reaction is promoted to generate a reformed gas whose main component is hydrogen. The reforming catalyst layer 4 a and the burner combustion space 4 c are provided with temperature detectors (not shown) that detect their temperatures, and the temperature detection results are transmitted to the control unit 100.

  The desulfurizer 5 includes a desulfurizer temperature adjustment unit 5a used for temperature adjustment such as heating at the time of startup, and decomposes and removes organic substances containing sulfur such as odorant from the fuel supplied from the fuel blower 21.

  The fuel preheater 6 preheats the fuel before being introduced into the reforming unit 4 and also gives heat to the reformed gas generated from the reforming unit 4.

  The shift reactor first stage 7 includes a shift reactor first stage temperature control unit 7 a used for temperature control such as heating at the time of startup, and promotes the shift reaction for the reformed gas supplied from the reforming unit 4.

  The shift reactor second stage 8 includes a shift reactor second stage temperature control unit 8a used for temperature control such as heating at start-up, and further shifts the reformed gas supplied from the shift reactor first stage 7. Promote the reaction.

  The process line condensation heat exchanger 9 condenses water vapor by heat exchange with cooling water for the reformed gas supplied from the second stage 8 of the shift reactor.

  The PROX 10 includes a PROX temperature control unit 10a such as a cooling fan, and burns and removes carbon monoxide by a selective oxidation reaction with respect to the supplied reformed gas, thereby reducing the concentration of carbon monoxide.

  The reforming water evaporator 11 converts the reforming water supplied from the reforming water pump 25 into a two-phase flow or superheated steam.

  The water evaporator outlet pressure loss element 12 causes a certain pressure loss when water vapor supplied from the reforming water evaporator 11 is passed.

  The starting fuel pressure loss element 13 causes a certain pressure loss when the fuel supplied from the fuel blower 21 is passed.

  The exhaust heat recovery device 14 recovers heat from the burner combustion space 4c through the high temperature side of the reforming water evaporator 11 and used for evaporation of the reforming water together with the exhaust gas from the fuel cell cathode 3b.

  The ventilation fan 15 mixes the exhaust gas heat recovered by the exhaust heat recovery device 14 with the ventilation of the entire fuel cell power generation device 1 and discharges it to the outside.

  The fuel inlet pressure gauge 16 measures the pressure of fuel drawn by the fuel blower 21 through the fuel inlet cutoff valve 30.

  The reformer pressure gauge 17 measures the pressure of the fuel introduced into the reforming unit 4 through the reformer inlet shutoff valve 32.

  The fuel flow meter 18 measures the flow rate of fuel drawn through the fuel inlet shut-off valve 30 by the fuel blower 21.

  The burner air flow meter 19 measures the flow rate of air drawn by the burner air blower 22.

  The fuel blower 21 draws fuel into the first system and the second system that communicate with the reforming unit 4.

  The burner air blower 22 draws external air into the reformer burner 4b.

  The cathode air blower 23 draws external air into the fuel cell cathode 3b.

  The PROX air blower 24 draws in air for mixing with the reformed gas supplied to the PROX 10 from the outside.

  The reforming water pump 25 supplies reforming water from a pure water tank installed outside the reforming device 2 to the reforming water evaporator 11 in the reforming device 2.

  The anode off-gas line condensation heat exchanger 27 converts the reformed gas from which hydrogen from the fuel cell anode 3a has been consumed or the reformed gas supplied through the fuel cell anode bypass line 37A by steam exchange with cooling water. Then, the reformed gas whose dew point is adjusted is supplied to the reforming section burner 4b.

  The anode off gas line condensed water discharge device 28 discharges the condensed water generated by the anode off gas line condensation heat exchanger 27.

  The process line condensing heat exchanger pressure gauge 29 measures the pressure of the reformed gas near the process line condensing heat exchanger 9 (for example, downstream of the process line condensing heat exchanger 9).

  The fuel inlet shut-off valve 30 is an open / close valve that shuts off and releases the fuel supplied from the fuel inlet by the fuel blower 21 by an opening / closing operation.

  The reformer inlet shut-off valve 32 is an open / close valve that shuts off and releases the fuel supplied to the desulfurizer 5 in the reformer 2 through the second path by the fuel blower 21 by an opening / closing operation.

  The burner fuel shut-off valve 33 is an open / close valve that shuts off and releases the fuel supplied to the reformer burner 4b in the reformer 2 through the first path by the fuel blower 21 by opening and closing operations.

  The PROX air shut-off valve 34 is an open / close valve that shuts off and releases the air supplied by the PROX air blower 24 by an open / close operation.

  The fuel cell anode inlet shut-off valve 35 is an open / close valve that shuts off and releases the reformed gas supplied to the inlet of the fuel cell anode 3a by opening and closing operations.

  The fuel cell anode outlet shut-off valve 36 is an open / close valve that shuts off and releases the reformed gas discharged from the outlet of the fuel cell anode 3a by opening and closing operations.

  The fuel cell anode bypass line 37A is a pipe that bypasses the fuel cell anode 3a from upstream to downstream, and connects the upstream of the fuel cell anode inlet cutoff valve 35 and the downstream of the fuel cell anode outlet cutoff valve 36.

  The fuel cell anode bypass line shut-off valve 37 is an on-off valve that shuts off and releases the reformed gas through the fuel cell anode bypass line 37A by opening and closing operations.

  The recycle line 38 </ b> A is a pipe that recycles part of the reformed gas from the downstream of the process line condensing heat exchanger 9 to the upstream of the fuel blower 21, and is downstream of the process line condensing heat exchanger 9 and upstream of the fuel blower 21. Connect with.

  The recycle line shut-off valve 38 is an open / close valve that shuts off and releases the reformed gas recycled through the recycle line 38A by opening and closing operations.

  The reforming water evaporator water drain shut-off valve 39 is an on-off valve that shuts off and releases the reforming water discharged from the reforming water evaporator 11 by an opening / closing operation.

  The process line condensed water discharge device 40 discharges the condensed water generated by the process line condensation heat exchanger 9 condensing water vapor.

  The process line condensate drain device outlet shut-off valve 41 is an on-off valve that shuts off and releases the condensate discharged from the process line condensate drain device 40 outlet by opening and closing operations.

  The control unit 100 is responsible for the overall operation of the fuel cell power generation device 1 and includes a fuel inlet pressure gauge 16, a reformer pressure gauge 17, a fuel flow meter 18, a burner air flow meter 19, a purge fuel installed in each part. The detection results of various sensors such as the flow meter 20 and the process line condensing heat exchanger pressure gauge 29 are taken in, and the process line condensing heat exchanger 9, the fuel blower 21, the burner air blower 22, and the cathode air blower according to their values. 23, controls the operation of auxiliary equipment such as the PROX air blower 24, the reforming water pump 25, and various shut-off valves 30, 32, 33, 34, 35, 36, 37, 38, 39, and 41.

  For example, when the control unit 100 stops the fuel cell power generator 1, at least the fuel cell anode inlet shut-off valve 35 and the fuel cell anode bypass line shut-off valve 37 are closed, and the reforming water evaporator drain shutoff valve is closed. 39 is opened to drain the reforming water from the reforming water evaporator 11, the reforming water evaporator draining shut-off valve 39 is closed, and then a certain amount of reforming water is supplied to the reforming device 2. The pressure value measured by the process line condenser heat exchanger pressure gauge 29 is constant by opening / closing at least the reformer inlet shutoff valve 32, the fuel cell anode inlet shutoff valve 35, or the fuel cell anode bypass line shutoff valve 37. It has a function to control to be within the range.

  More specifically, after supplying a certain amount of reforming water to the reformer 2, the control unit 100 monitors the pressure measured by the process line condensing heat exchanger pressure gauge 29, and the pressure is the first. Is closed, the reformer inlet shutoff valve 32 is closed to stop the supply of fuel and the supply of reforming water, and the refrigerant flow in the process line condensation heat exchanger 9 is started. When the pressure is equal to or higher than the second value higher than the first value, the refrigerant flow rate in the process line condensation heat exchanger 9 is increased, while when the pressure is equal to or lower than the third value. Stops the refrigerant flow in the process line condensation heat exchanger 9, and when the pressure falls below a fourth value lower than the third value, the reformer inlet shut-off valve 32 is opened to supply fuel. In addition, reformed water is supplied and the pressure is less than the fifth value, which is lower than the fourth value. And if it becomes has a function of performing a control for increasing the supply amount of the fuel and the reforming water.

  Furthermore, when the temperature of the reforming unit 4 of the reformer 2 becomes equal to or lower than a predetermined value (predetermined value), the control unit 100 opens at least the reformer inlet shut-off valve 32 and reforming water. After the evaporator water drain shutoff valve 39 is opened to drain the reforming water from the reforming water evaporator 11, the reformer inlet shutoff valve 32 and the reforming water evaporator drain shutoff valve 39 are closed, and at least Pressure of fuel supplied to the reformer 2 with the fuel cell anode inlet shut-off valve 35 and the fuel cell anode bypass line shut-off valve 37 closed (pressure measured by the reformer pressure gauge 17) or process line condensation The pressure of the reformed gas in the vicinity of the heat exchanger 9 (pressure measured by the process line condensing heat exchanger pressure gauge 29) is monitored, and when the pressure falls below a predetermined value, the reformer inlet shut-off valve 32 Open and the pressure is a predetermined value When it becomes the upper has a function of performing closing control reformer inlet shutoff valve 32.

  In the above configuration, during operation of the fuel cell power generator 1, fuel is drawn by the fuel blower 21 through the fuel inlet shutoff valve 30, and the pressure at that time is measured by the fuel inlet pressure gauge 16 and the flow rate is measured by the fuel flow meter 18. . There is an outlet of the recycle line 38 </ b> A upstream of the fuel blower 21, and a small amount of reformed gas is recycled through the recycle line shut-off valve 38. The downstream of the fuel blower 21 is divided into two systems. In the first system, fuel is supplied as auxiliary fuel to the reforming section burner 4b in the reforming apparatus 2 through the starting fuel pressure loss element 13 and the burner fuel cutoff valve 33. Is done. In the second system, fuel is supplied to the desulfurizer 5 in the reformer 2 through the reformer inlet shut-off valve 32, and organic substances containing sulfur such as odorant are decomposed and removed.

  On the other hand, from the pure water tank installed outside the reforming device 2, reforming water is supplied to the reforming device 2 by the reforming water pump 25, and two-phase flow or superheated steam is generated by the reforming water evaporator 11. After that, the water passes through the water evaporator outlet pressure loss element 12, joins with the reformed fuel derived from the desulfurizer 5, is preheated by the fuel preheater 6, and is introduced into the reforming catalyst layer 4a. While passing through the reforming catalyst layer 4a, the reforming reaction proceeds by the heat transfer from the burner combustion space 4c in the reforming section 4, and the high temperature side of the fuel preheater 6 as reformed gas whose main component is hydrogen. And then introduced into the shift reactor first stage 7 and subsequently into the shift reactor second stage 8.

  The reformed gas derived from the shift reactor contains water vapor at a dew point that is higher than the ambient temperature of the fuel cell power generation device 1, and in particular, it may condense in the course of circulation through the recycle line 38 </ b> A and hinder the circulation. For this reason, water vapor is condensed by the process line condensing heat exchanger 9 and discharged by the process line condensed water discharge device 40. In FIG. 1, as an example of such a process line condensed water discharge device 40, a float type self-powered liquid level adjustment valve is illustrated, but water is discharged such as a form in which an outlet valve is opened and closed using a water level sensor. Other types may be adopted if possible. Further, the process line condensate drain device outlet shut-off valve 41 provided at the outlet of the process line condensate drain device 40 is essentially unnecessary as long as a self-powered liquid level adjustment valve is used, but can be used in a stop operation described later. It is desirable to install in. As an example of the process line condensate discharge device outlet shut-off valve 41, a check valve may be employed in addition to an electromagnetic valve if a pressure difference between inside and outside can be expected. Further, the process line condensing heat exchanger pressure gauge 29 provided in the vicinity of the process line condensing heat exchanger 9 is installed downstream because it is preferable that the temperature is low and the risk of condensation is low in the example of FIG. However, it may be installed upstream.

  On the other hand, the PROX air sent by the PROX air blower 24 is mixed with the reformed gas derived from the process line condensation heat exchanger 9 through the PROX air shut-off valve 34, and is supplied to the PROX (CO selective oxidation reactor) 10. be introduced. In PROX10, carbon monoxide is burned and removed by a selective oxidation reaction, and the concentration is 10 ppm or less. The reformed gas derived from the PROX 10 is introduced into the fuel cell anode 3a through the fuel cell anode inlet shut-off valve 35, and consumes hydrogen by reaction with oxygen in the air supplied to the fuel cell cathode 3b through the cathode air blower 3. And is led out through the fuel cell anode outlet shut-off valve 36.

  A fuel cell anode bypass line shut-off valve 37 is disposed in the fuel cell anode bypass line 37A that connects the upstream of the fuel cell anode inlet shut-off valve 35 and the downstream of the fuel cell anid outlet shut-off valve 36. The fuel cell anode bypass line shut-off valve 37 is opened when the internal pressure of the reformer 2 rises excessively during startup or stop.

  The reformed gas derived from the fuel cell anode outlet shut-off valve 36 has a dew point increased because its flow rate is reduced due to hydrogen consumption. Therefore, the water vapor is condensed by the anode off-gas line condensing heat exchanger 27 and discharged through the anode off-gas line condensed water discharging device 28. The reformed gas with the dew point adjusted in this way is introduced into the reforming section burner 4 b and burned together with the air introduced through the burner air flow meter 19 by the burner air blower 22. The combustion exhaust gas passes through the high temperature side of the reforming water evaporator 11 from the burner combustion space 4c and is used for evaporation of the reforming water, and then is led out to the outside of the reforming device 2 to be discharged from the fuel cell cathode 3b. At the same time, after the heat is recovered by the exhaust heat recovery device 14, it is mixed with the ventilation of the entire fuel cell power generation device 1 by the ventilation fan 15 and discharged outside.

  Next, with reference to the flowchart of FIG. 2 and the timing chart of FIG. 3, the operation by the control unit 100 when stopping the fuel cell power generation device according to the embodiment will be described. In FIG. 2 and FIG. 3, each component is simply expressed only by its reference numerals to simplify the description.

  When the fuel cell power generation device 1 is instructed to stop power generation (step S1), the following processing (step S2) is performed.

  The operation of the cathode air blower 23 is stopped to stop power generation. Further, the fuel blower 21 is stopped, the fuel inlet shutoff valve 30 and the reformer inlet shutoff valve 32 are closed, and the operation of the reforming water pump 25 is stopped to stop the supply of the raw material to the reformer, The reforming water evaporator drain shutoff valve 39 is closed, the burner fuel shutoff valve 33 is closed, the fuel supply to the reforming section burner 4b is stopped, the flame is extinguished, and the temperature is lowered. Note that the operation of the burner air blower 22 is continued in order to lower the temperature of the reforming unit 4 and the reformer 2 as a whole. Further, the PROX air blower 24 is stopped, the PROX air shutoff valve 34 is closed, and the PROX air flow is stopped. Further, the recycling of the reformed gas is stopped by closing the recycle line shut-off valve 38. Further, the desulfurizer temperature controller 5a, the fuel preheater temperature controller 6a, the shift reactor first stage temperature controller 7a, the shift reactor second stage temperature controller 8a, and the PROX temperature controller 10a are stopped for temperature reduction. Then, the fuel cell anode inlet shut-off valve 35, the fuel cell anode outlet shut-off valve 36, the fuel cell anode bypass line shut-off valve 37, and the process line condensate discharge device outlet shut-off valve 41 are closed, and the reformer 2 and the process line are closed. Close the compartment containing the condensation heat exchanger 9. At this stage, it is desirable to temporarily stop the refrigerant flow in the process line condensation heat exchanger 9. This is because there is a possibility that a desirable result may not be obtained if there is a device that depressurizes the compartment in the next operation, and the process line condensed water discharge device 40 cannot discharge the water.

  At the stage where the above conditions are satisfied, the reforming water evaporator drain shutoff valve 39 is opened to drain the reforming water from the reforming water evaporator 11 (step S3).

Since all the shut-off valves other than the reforming water evaporator water drain shut-off valve 39 are closed, the amount of gas in the reforming device 2 increases by the amount drained from the reforming water evaporator 11, and the reforming device pressure gauge 17. The measured value decreases. If this increment is ΔP,
ΔP> (absolute pressure of reformer pressure gauge 17 before stoppage or designed absolute pressure of reformer pressure gauge 17) × {(reformed water evaporator drain-off valve 39 to reformed water evaporator 11 Piping volume to the inlet)} + (Volume in the reforming water evaporator 11)} ÷ (Volume in the reformer 2)
The reforming water evaporator drain shut-off valve 39 is closed when it becomes, or the time required for draining is measured in advance, and the reforming water evaporator drain shut-off valve 39 is opened and then closed after the time has elapsed. (Steps S4 and S5).

  As a result, the reforming water can be removed without wastefully leaking the gas phase reformed gas. Further, by draining in this way, it is possible to reduce the risk that the internal pressure of the reformer 2 will increase in the subsequent shutoff operation.

  After draining the reforming water evaporator 11 and closing the reforming water evaporator drain shutoff valve 39, the reforming water pump 25 is operated (step S5), and the reforming water evaporator 11 reaches the inlet. A certain amount of reforming water that does not enter the reforming water evaporator 11 while filling the pipe, for example, a modification of the piping volume from the reforming water evaporator drain shutoff valve 39 to the reforming water evaporator 11 inlet. The quality water is supplied and refilling is performed (step S6), and the reforming water pump 25 is stopped (step S7).

  In this way, when the preparation for the reformed gas purge is completed, it is confirmed whether the value of the process line condensing heat exchanger pressure gauge 29 is equal to or greater than a predetermined value bb (step S8).

  Since water is sucked in when the pressure is resumed from the negative pressure state, when the value of the process line condensing heat exchanger pressure gauge 29 is lower than the predetermined value bb, the fuel cell anode bypass line shut-off valve 37 is opened and the burner combustion space 4c is opened. The gas phase pressure rise due to the residual heat is waited for a certain time, and then the fuel cell anode bypass line shutoff valve 37 is closed (step S9). If it becomes more than predetermined value bb, the process line condensed-water discharge apparatus exit cutoff valve 41 will be opened (step S10).

  Thereafter, until the temperature of the reforming catalyst layer 4a and the temperature of the burner combustion space 4c are equal to or lower than a predetermined value (No in step S11), the process line condensation is performed by operating various auxiliary devices as follows. Control is performed so that the pressure measured by the heat exchanger pressure gauge 29 falls within a certain range.

  In the control, introduction of the reforming material by the fuel blower 21 and refrigerant circulation by the process line condensing heat exchanger 9 are performed as appropriate. The introduction of the reforming material is a factor that increases the pressure of the reformer 2. On the other hand, the removal of water vapor by condensation in the process line condensation heat exchanger 9 and the temperature reduction of the reformer 2 as a whole cause the pressure to decrease. Therefore, the process line condensing heat exchanger pressure gauge 29 is installed at the place where the pressure is the lowest, and the pressure holding control shown below is performed while monitoring the pressure of the process line condensing heat exchanger pressure gauge 29.

  For example, when the pressure of the process line condensing heat exchanger pressure gauge 29 becomes a predetermined value a or more (Yes in Step S12), the fuel inlet shut-off valve 30 and the reformer inlet shut-off valve 32 are closed and the fuel blower 21 is closed. And by stopping the operation of the reforming water pump 25, the fuel supply is stopped and the reforming water supply is stopped (step S13), and the refrigerant flow in the process line condensing heat exchanger 9 is started (step S14). ). At this time, since the condensation is performed in the cut-off state, the process line condensing heat exchanger 9 is depressurized and the flow from the reforming unit 4 is made. If the pressure continues to increase and the pressure becomes equal to or higher than the predetermined value aa higher than the predetermined value a (Yes in step S15), the refrigerant flow rate in the process line condensation heat exchanger 9 is increased (step S15). S16).

  On the other hand, when the pressure becomes equal to or lower than the predetermined value c (Yes in Step S17), the refrigerant flow in the process line condensation heat exchanger 9 is stopped (Step S18). If the pressure continues to drop and the pressure falls below the predetermined value b lower than the predetermined value c (Yes in step S19), the fuel inlet shut-off valve 30 and the reformer inlet shut-off valve 32 are opened and the fuel is discharged. By operating the blower 21 and the reforming water pump 25, fuel is supplied and reforming water is supplied (step S20). The supply ratio (S / C) of the reformed fuel and the reformed water is selected to be in the range of 2.5 to 3.5, and it is desirable to supply a small amount or intermittently. If the pressure continues to drop and the pressure falls below the predetermined value bb lower than the predetermined value b (Yes in step S21), the amount of fuel supplied from the fuel blower 21 and the reforming from the reforming water pump 25 are improved. Increase quality water supply.

  While such control is continued, when the temperature of the reforming catalyst layer 4a and the temperature of the burner combustion space 4c become equal to or lower than predetermined values and the temperature lowering is completed (Yes in step S11), the fuel inlet cutoff valve 30 and By closing the reformer inlet shutoff valve 32 and stopping the operation of the fuel blower 21 and the reforming water pump 25, the fuel supply is stopped and the reforming water supply is stopped (step S23). Note that the value below the predetermined value shown in step S11 is a temperature at which incompatibility such as carbon generation does not occur even if fuel is supplied to the reforming catalyst in the absence of water vapor, and also depends on the type of fuel or reforming catalyst. However, it is desirable that it is 280-350 degreeC.

  Next, the fuel inlet shutoff valve 30 and the reformer inlet shutoff valve 32 are opened, the reforming water evaporator drain drain shutoff valve 39 is opened, and the reforming water evaporates from the reformer 2 via the desulfurizer 5. The gas up to the vessel 11 is purged with fuel (step S24). The fuel introduced from the inlet of the reformer 2 passes through the desulfurizer 5, and the reformed water evaporator 11 is purged with the desulfurized fuel. The possibility of pressure increase due to is reduced. Further, since the downstream side from the reforming unit 4 is not purged, the reformed gas containing hydrogen in this section is retained. Further, it is possible to prevent the possibility that a gas containing sulfur flows into the reforming unit 4 at the next start-up.

  Then, after a predetermined time has elapsed (Yes in step S25), the fuel inlet cutoff valve 30 and the reformer inlet cutoff valve 32 are closed, and the reforming water evaporator drain cutoff valve 39 is closed (step S26). In this state, the pressure measured by the reformer pressure gauge 17 or the process line condensing heat exchanger pressure gauge 29 is monitored. When the pressure falls below a predetermined value, the reformer inlet shut-off valve 32 is opened and the pressure is measured. When the pressure exceeds a predetermined value, the reformer inlet shutoff valve 32 is closed, and pressure holding control is performed so that fuel is supplied mainly for the pressure drop due to the temperature drop (step S27). In this case, even if the hydrogen concentration in the reformed gas concentration is lowered by the fuel supply, the reformed gas is not completely replaced by the fuel, so the atmosphere with hydrogen around the catalyst is maintained. Water vapor can be gradually removed.

  According to the first embodiment, with a simple configuration, moisture is removed during a stop operation while retaining a reformed gas suitable for the catalyst of the reformer 2 in the reformer 2, and the reformer 2 Even when the temperature drop is completed, the inside can be kept from getting wet with condensed water. In addition, it is possible to prevent the pressure from becoming excessive during the stop operation, or the pressure from dropping to suck in water from the process line condensed water discharge device 9. Further, during the stop operation, the reformed gas can be prevented from being replaced with another gas, and there is no fear that the combustible gas is discharged from the outlet of the reformer 4.

(Second Embodiment)
Next, a second embodiment will be described.

  In the second embodiment, parts that are the same as those in the configuration of the first embodiment shown in FIG. 1 are given the same reference numerals, and redundant descriptions are omitted. Below, it demonstrates centering on a different part from 1st Embodiment.

  FIG. 4 is a configuration diagram showing an example of the configuration of the fuel cell power generator according to the second embodiment.

  In the fuel cell power generator 1 shown in FIG. 4, the PROX 10 exists not on the downstream side of the process line condensation heat exchanger 9 but on the upstream side. Further, the PROX air supplied by the PROX air blower 24 is not mixed with the reformed gas derived from the process line condensation heat exchanger 9 through the PROX air shutoff valve 34 but is derived from the shift reactor 8. The reformed gas is mixed and introduced into a PROX (CO selective oxidation reactor) 10. In this case, the gas whose dew point has been lowered in the process line condensing heat exchanger 9 contains nitrogen, and there is a risk that ammonia will be generated in the reforming unit 4 if it is recycled. Therefore, the recycle line 38A is not provided in this embodiment.

  Other configurations and operations are the same as those in the first embodiment described above.

  According to the second embodiment, the basic configuration and operation are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

(Third embodiment)
Next, a third embodiment will be described.

  Note that in the third embodiment, parts that are the same as those in the configuration of the first embodiment illustrated in FIG. 1 are given the same reference numerals, and redundant descriptions are omitted. Below, it demonstrates centering on a different part from 1st Embodiment.

  FIG. 5 is a configuration diagram showing an example of the configuration of the fuel cell power generator according to the third embodiment.

  In the fuel cell power generator 1 shown in FIG. 5, the PROX 10 is not provided, but a methanation reactor 26 is provided upstream of the process line condensation heat exchanger 9. The methanation reactor 26 includes a methanation reactor temperature control unit 26a used for temperature control, and reduces the carbon monoxide concentration by generating methane from carbon monoxide and hydrogen. Note that PROX air is not used for mixing with the reformed gas. Since the methanation reactor 26 operates without PROX air, the gas whose dew point has been lowered by the process line condensation heat exchanger 9 does not contain nitrogen, and is suitable as a gas to be supplied to the desulfurizer 5. Therefore, in this embodiment, a recycling line 38A is provided.

  Other configurations and operations are the same as those in the first embodiment described above.

  According to the third embodiment, the basic configuration and operation are the same as those of the first embodiment described above, and the same effects as those of the first embodiment can be obtained.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell power generation device, 2 ... Reformer, 3 ... Fuel cell, 3a ... Fuel cell anode, 3b ... Fuel cell cathode, 4 ... Reformer, 4a ... Reformer catalyst layer, 4b ... Reformer burner, 4c ... Burner combustion space, 5 ... Desulfurizer, 5a ... Desulfurizer temperature adjustment unit, 6 ... Fuel preheater, 6a ... Fuel preheater temperature adjustment unit, 7 ... First stage of shift reactor, 7a ... First stage temperature of shift reactor Control part, 8 ... Shift reactor second stage, 8a ... Shift reactor second stage temperature control part, 9 ... Process line condensation heat exchanger, 10 ... PROX, 10a ... PROX temperature control part, 11 ... Reformed water evaporation 12 ... Water evaporator outlet pressure loss element, 13 ... Startup fuel pressure loss element, 14 ... Waste heat recovery device, 15 ... Ventilation fan, 16 ... Fuel inlet pressure gauge, 17 ... Reformer pressure gauge, 18 ... Fuel Flow meter, 19 ... Burner air flow meter, 20 ... Purge fuel 21. Fuel blower, 22 ... Burner air blower, 23 ... Cathode air blower, 24 ... PROX air blower, 25 ... Reformed water pump, 26 ... Methanation reactor, 26a ... Methanation reactor temperature control unit, 27 ... Anode off-gas line condensing heat exchanger, 28 ... Anode off-gas line condensed water discharge device, 29 ... Process line condensing heat exchanger pressure gauge, 30 ... Fuel inlet shut-off valve, 32 ... Reformer inlet shut-off valve, 33 ... Burner Fuel cutoff valve, 34 ... PROX air cutoff valve, 35 ... Fuel cell anode inlet cutoff valve, 36 ... Fuel cell anode outlet cutoff valve, 37 ... Fuel cell anode bypass line cutoff valve, 37A ... Fuel cell anode bypass line, 38 ... Recycle Line shut-off valve, 38A ... Recycle line, 39 ... Reformed water evaporator drain shut-off valve, 40 ... Process Line condensate drain, 41 ... condensate drain outlet shutoff valve, 100 ... control unit.

Claims (5)

A reforming water evaporator that generates steam from the reforming water, a reforming device that generates reformed gas containing hydrogen from hydrocarbons contained in fuel and steam generated by the reforming water evaporator, and A reformer inlet shut-off valve that shuts off and releases the fuel supplied to the reformer inlet by opening and closing operation, and a process line condensation heat exchange that condenses water vapor contained in the reformed gas generated in the reformer A fuel cell anode that consumes hydrogen contained in the reformed gas passing through the process line condensing heat exchanger, and shutting off and releasing the reformed gas supplied to the inlet of the fuel cell anode by opening and closing operations A fuel cell anode inlet shut-off valve to perform, a fuel cell anode bypass line for bypassing the fuel cell anode from upstream to downstream, and reforming through the fuel cell anode bypass line A fuel cell anode bypass line shut-off valve that shuts off and releases the reformed water by opening and closing operation, and reforming that discharges and releases the reformed water from the branch of the reforming water upstream of the reforming water evaporator and releases it by opening and closing operation A fuel cell power generator comprising a water evaporator drain shutoff valve,
A process line condensing heat exchanger pressure gauge for measuring the pressure of the reformed gas in the vicinity of the process line condensing heat exchanger;
When stopping the fuel cell power generation device, the reforming water evaporator drain shutoff valve is opened with at least the fuel cell anode inlet shutoff valve and the fuel cell anode bypass line shutoff valve closed. After discharging the reforming water from the water evaporator and closing the reforming water evaporator drain shut-off valve, supply a certain amount of reforming water to the reforming device, at least the reforming device inlet shut-off valve, Control for controlling the fuel cell anode inlet shut-off valve or the fuel cell anode bypass line shut-off valve so that the pressure value measured by the process line condensing heat exchanger pressure gauge falls within a certain range. And a fuel cell power generator.   2. The fuel cell power generator according to claim 1, wherein the control unit monitors the pressure measured by the process line condensing heat exchanger pressure gauge after supplying the fixed amount of reformed water to the reformer. 3. If the pressure exceeds a certain value, the reformer inlet shutoff valve is closed to stop the supply of fuel and the supply of reforming water, or the refrigerant of the process line condensation heat exchanger Starts distribution or controls to increase the refrigerant flow rate of the process line condensation heat exchanger, while if the pressure falls below a certain value, stops the refrigerant flow of the process line condensation heat exchanger Or a fuel that supplies fuel and supplies reformed water or increases the amount of fuel and reformed water supplied by opening the reformer inlet shut-off valve. Pond power generation equipment.   2. The fuel cell power generator according to claim 1, wherein the control unit monitors the pressure measured by the process line condensing heat exchanger pressure gauge after supplying the fixed amount of reformed water to the reformer. 3. If the pressure exceeds the first value, the reformer inlet shut-off valve is closed to stop the fuel supply and the reforming water supply to stop the process line condensation heat exchanger. When the refrigerant flow is started and the pressure becomes a second value higher than the first value, the refrigerant flow rate of the process line condensation heat exchanger is increased, while the pressure is the third value The refrigerant flow in the process line condensing heat exchanger is stopped when the pressure is equal to or lower than the value of the reformer, and when the pressure is lower than the fourth value lower than the third value, the reformer inlet Open the shut-off valve to supply fuel and supply reformed water Feeding, and the fuel cell power plant and performing control for increasing the supply amount of the fuel and the reforming water if the pressure becomes equal to or lower than the fourth fifth value lower than the value.   4. The fuel cell power generator according to claim 1, wherein when the temperature of the reforming section of the reformer becomes equal to or lower than a predetermined value, the control means at least the reformer Open the inlet shutoff valve and open the reformer water evaporator drain shutoff valve to discharge the reformed water from the reformer water evaporator, and shut off the reformer inlet shutoff valve and the reformer water evaporator drainer After closing the valve, at least the fuel cell anode inlet shutoff valve and the fuel cell anode bypass line shutoff valve are closed, and the pressure of fuel supplied to the reformer or the process line condensing heat exchanger pressure gauge When the pressure falls below a predetermined value, the reformer inlet shut-off valve is opened, and when the pressure rises above a predetermined value, the reformer inlet shut-off valve opens. Control to close The method of stopping the fuel cell power generation system according to claim and. A reforming water evaporator that generates steam from the reforming water, a reforming device that generates reformed gas containing hydrogen from hydrocarbons contained in fuel and steam generated by the reforming water evaporator, and A reformer inlet shut-off valve that shuts off and releases the fuel supplied to the reformer inlet by opening and closing operation, and a process line condensation heat exchange that condenses water vapor contained in the reformed gas generated in the reformer A fuel cell anode that consumes hydrogen contained in the reformed gas passing through the process line condensing heat exchanger, and shutting off and releasing the reformed gas supplied to the inlet of the fuel cell anode by opening and closing operations A fuel cell anode inlet shut-off valve to perform, a fuel cell anode bypass line for bypassing the fuel cell anode from upstream to downstream, and reforming through the fuel cell anode bypass line A fuel cell anode bypass line shut-off valve that shuts off and releases the reformed water by opening and closing operation, and reforming that discharges and releases the reformed water from the branch of the reforming water upstream of the reforming water evaporator and releases it by opening and closing operation A method for stopping a fuel cell power generation device comprising a water evaporator drain shutoff valve,
When the fuel cell power generation device is stopped by the control means, the reforming water evaporator drainage cutoff valve is opened with at least the fuel cell anode inlet cutoff valve and the fuel cell anode bypass line cutoff valve closed. Discharging the reforming water from the reforming water evaporator and closing the reforming water evaporator water drain shutoff valve, and then supplying a certain amount of reforming water to the reforming device, at least the reforming device By operating the inlet shutoff valve, the fuel cell anode inlet shutoff valve, or the fuel cell anode bypass line shutoff valve, the pressure value of the reformed gas in the vicinity of the process line condensing heat exchanger is kept within a certain range. A method for stopping the fuel cell power generation apparatus, characterized by:

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