JP2005251703A - Operation method in power failure in fuel gas manufacturing power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize and simplify a whole system, and to surely continue power generation in a power failure. <P>SOLUTION: When a power failure state is detected, an auxiliary power supply part 82 is connected to supply starting power of a stationary fuel cell 74 including a compressor 80 from the auxiliary power supply part 82; and power generation of the stationary fuel cell 74 is started. Then, supply of power from the auxiliary power supply part 82 is stopped, and power from the stationary fuel cell 74 is used as a home power source. The auxiliary power supply part 82 is set at capacity capable of supplying only the starting power of the stationary fuel cell 74. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention, for example, reforms a hydrogen-containing fuel containing hydrocarbons or alcohols to obtain a reformed gas, and purifies the hydrogen-rich fuel gas by removing unnecessary substances from the reformed gas. A refining unit; a storage unit that stores the fuel gas; a power generation unit that generates power by being supplied with the fuel gas; and an auxiliary power unit that is connected to the power generation unit and supplies only power for starting the power generation unit. It is related with the operation method at the time of a power failure in a fuel gas production power generation system provided with.

  For example, after reforming a hydrocarbon fuel such as natural gas or a hydrogen-containing fuel containing alcohol such as methanol to obtain a hydrogen-containing gas (reformed gas), the fuel cell (power generation unit) ) Etc., a hydrogen production device (fuel gas production power generation system) is employed.

  In this type of hydrogen production apparatus, a hydrocarbon fuel such as LPG (liquefied petroleum gas) or city gas is steam reformed to produce a hydrogen-containing gas that is a high-concentration hydrogen-rich gas, and for example, PSA (Pressure Swing Adsorption) ) High-purity hydrogen is separated from the hydrogen-containing gas by pressure adsorption through an apparatus.

  In this case, in order to reduce the size of the entire facility, an on-site hydrogen production facility in which a hydrogen production apparatus is installed at a supply place is considered. For example, as shown in FIG. 6, the hydrogen production facility disclosed in Patent Document 1 includes a desulfurization apparatus 1 that desulfurizes a sulfur content in a reforming raw material that is a hydrocarbon. The desulfurized reforming raw material is sent to the steam reformer 2 to produce a hydrogen-containing gas by steam reforming.

  The hydrogen-containing gas produced by the steam reformer 2 is sent to the shift reaction device 3, where carbon monoxide in the hydrogen-containing gas is converted to carbon dioxide and removed. Further, the hydrogen-containing gas from which carbon monoxide has been removed is sent to the hydrogen PSA device 4 where impurities other than hydrogen are adsorbed and removed by the adsorbent, and high-purity hydrogen is supplied to the hydrogen supply device 5. . On the other hand, part of the hydrogen is supplied to the polymer electrolyte fuel cell 6 as fuel gas for power generation.

  The polymer electrolyte fuel cell 6 generates electric power for operating the hydrogen production apparatus, and the polymer electrolyte fuel cell 6 and the secondary battery facility 7 are electrically connected. The hydrogen supplied to the hydrogen supply device 5 is distributed and supplied to hydrogen-using automobiles, household fuel cells, and the like.

  The hydrogen production apparatus is usually operated by using both the power of the polymer electrolyte fuel cell 6 and external power, but when power is not supplied from the outside due to a power failure such as during a disaster. Is supplied with electric power only by the polymer electrolyte fuel cell 6.

  Furthermore, when the demand for hydrogen is low, the amount of power generated by the polymer electrolyte fuel cell 6 is increased and stored in the secondary battery facility 7, while when the demand for hydrogen is high, the polymer electrolyte fuel cell 6 By supplying electricity from the secondary battery equipment 7 while reducing the amount of power generated, it is possible to cope with fluctuations in demand for hydrogen.

JP 2003-95612 A (FIG. 1)

  However, the secondary battery equipment 7 is configured to store electricity when the demand for hydrogen is low, while supplying electricity when the demand for hydrogen is high, and the secondary battery equipment 7 itself is considerably large. It has been pointed out that the

  In addition, the secondary battery equipment 7 having a relatively large capacity must be stored, and the power of the polymer electrolyte fuel cell 6 cannot be used efficiently, which is not economical. Further, when electricity is supplied from the secondary battery equipment 7 and the charge amount of the secondary battery equipment 7 is decreasing, if a power failure occurs, a supplement for operating the polymer electrolyte fuel cell 6 will be provided. Therefore, there is a problem that the solid polymer fuel cell 6 cannot be reliably generated during a power failure because the power cannot be sufficiently supplied to the battery.

  The present invention solves this type of problem, and provides a method for operating during a power failure in a fuel gas production power generation system capable of downsizing the entire system and continuing power generation reliably even during a power failure. For the purpose.

  The present invention includes a reforming unit that reforms a hydrogen-containing fuel to obtain a reformed gas, a purification unit that removes unnecessary substances from the reformed gas to purify a hydrogen-rich fuel gas, and stores the fuel gas Power outage in a fuel gas production power generation system comprising: a storage unit that performs power generation by being supplied with the fuel gas; and an auxiliary power unit that is connected to the power generation unit and supplies only power for starting the power generation unit It is the driving method of time.

  Therefore, first, when it is detected that a power failure occurs, fuel gas is supplied from the storage unit to the power generation unit using the power of the auxiliary power supply unit, and oxidant gas is supplied to the power generation unit. . Thereby, the power generation by the power generation unit is started, and then the supply of power from the auxiliary power supply unit is stopped, while the power supply is performed from the power generation unit.

  Further, it is preferable that when the remaining amount of the fuel gas remaining in the storage unit is detected and the remaining amount of the fuel gas reaches a predetermined amount or less, the operation of the reforming unit and the purification unit is started to produce the fuel gas. .

  Furthermore, when the supply amount of the hydrogen-containing fuel to the reforming unit reaches a specified amount or less, the operation of the reforming unit and the purification unit is stopped, while power generation by the power generation unit is continued, When the remaining amount of fuel gas remaining in the storage unit reaches a specified amount or less, the power generation by the power generation unit is preferably stopped.

  In the present invention, since the auxiliary power supply unit dedicated to starting up the power generation unit is provided, the auxiliary power supply unit itself is effectively reduced in size, and the power generation by the power generation unit is reliably performed during a power failure. As a result, the entire fuel gas production power generation system can be easily made compact, and it is possible to cope with a good power failure.

  FIG. 1 is a schematic configuration diagram of a household fuel gas refining system (fuel gas production power generation system) 10 for carrying out an operation method during a power failure according to an embodiment of the present invention.

  The home fuel gas refining system 10 is modified to obtain a hydrogen rich gas (hereinafter referred to as reformed gas) by reforming a hydrogen-containing fuel, for example, a hydrocarbon fuel such as methane or propane (hereinafter referred to as reformed fuel). And a refining unit 14 for refining high-purity hydrogen gas (hereinafter referred to as fuel gas) from the hydrogen-rich gas, and a storage unit 16 for storing the fuel gas.

  The reforming unit 12 includes an evaporator 18 that has a combustion catalyst and evaporates the reforming fuel. A combustor 20 such as a burner is attached to the evaporator 18, and a reactor (reformer) 22 for reforming reforming fuel to obtain a reformed gas is provided downstream of the evaporator 18. Arranged. A cooler 24 that cools the reformed gas is disposed downstream of the reactor 22, and a gas that separates the cooled reformed gas into a gas component and moisture is disposed downstream of the cooler 24. A liquid separator 26 is provided.

  The reforming unit 12 is provided with an air supply mechanism 28. The air supply mechanism 28 includes an air compressor 30, and a reforming air supply path 32 and an off-gas discharge air supply path 36 are connected to the air compressor 30. The reforming air supply path 32 is connected to the evaporator 18, and the offgas discharge air supply path 36 is connected to the combustor 20 via a PSA mechanism 48 described later.

  The reforming air supply path 32 and the off-gas discharge air supply path 36 can be connected to the air compressor 30 via flow control valves 38a and 38b. In the reforming air supply path 32, a reforming fuel ejector 40 for supplying reforming fuel is disposed between the valve 38 a and the evaporator 18.

  A temperature sensor 44 for detecting the catalyst temperature is connected to the reactor 22, and a pressure gauge 45 is disposed in the reforming air supply path 32, upstream of the reforming fuel ejector 40. Is done.

  A PSA mechanism 48 constituting the purification unit 14 is connected to the downstream of the gas-liquid separator 26 via a reformed gas supply path 46, and the reformed gas from which moisture has been separated is supplied to the PSA mechanism 48. The A compressor 50 for pressure-feeding the reformed gas to the PSA mechanism 48 is connected to the reformed gas supply path 46.

  The PSA mechanism 48 includes a plurality of towers, for example, three towers (not shown) filled with an adsorbent that selectively adsorbs components other than hydrogen under high pressure and desorbs under reduced pressure. By making each adsorption tower perform cyclic operation consisting of adsorption, depressurization, pressure equalization, desorption and washing steps, high-purity hydrogen is taken out, while other components (unnecessary substances) are released as off-gas to the off-gas discharge passage 52. It is configured to do.

  The off gas discharge path 52 is connected to an off gas ejector 54. An off-gas discharge air supply path 36 is connected to one end of the off-gas ejector 54, and an off-gas flow path 56 is connected to the other end of the off-gas ejector 54. The off-gas ejector 54 has a function of sucking off-gas from the PSA mechanism 48 via the off-gas discharge air (compressed air) flowing from the off-gas discharge air supply path 36 to the off-gas flow path 56 by the air compressor 30.

  A fuel gas path 58 for discharging high purity hydrogen from each adsorption tower communicates with the PSA mechanism 48, and a compressor 60 is connected to the fuel gas path 58. The end of the fuel gas path 58 is connected to a filling tank 66 constituting the storage unit 16 through a valve 64. A branch fuel gas path 68 is provided in the middle of the fuel gas path 58, and a power generation tank 72 is connected to the branch fuel gas path 68 via a valve 70.

  The filling tank 66 supplies fuel gas to a fuel cell vehicle (not shown), while the power generation tank 72 is connected to a stationary fuel cell (power generation unit) 74 for supplying household power via a fuel gas supply path 76. A valve 78 is disposed in the fuel gas supply path 76 while being connected. For example, a compressor (or supercharger) 80 for supplying air as an oxidant gas is connected to the stationary fuel cell 74.

  The stationary fuel cell 74 is connected to an auxiliary power supply unit 82 that supplies only the starting power for the stationary fuel cell 74. The auxiliary power supply unit 82 includes, for example, a capacitor. The auxiliary power supply unit 82 is connected to a power supply box 84, and the power supply box 84 incorporates an AC / DC converter and a main power switch. The power supply box 84 supplies system auxiliary power including the compressor 80 and the like, and is connected to an external power supply.

  The home fuel gas refining system 10 communicates and controls with each auxiliary machine, and particularly in this embodiment, as a control unit for detecting whether or not a power failure occurs, for example, a control ECU (Electronic Control) Unit) 86. The control ECU 86 has a built-in ECU battery, for example, a lithium battery, and can be driven even if the power is cut off due to a power failure.

  The operation of the household fuel gas purification system 10 configured as described above will be described below.

  In the home fuel gas purification system 10, the air compressor 30 is operated via the control ECU 86, and the reforming air and the off-gas exhaust air are supplied to the reforming air supply path 32 and the off-gas exhaust air supply path 36, respectively. Sent to.

  The reforming air supplied to the reforming air supply path 32 is supplied to the evaporator 18, and the evaporator 18 contains, for example, reforming fuel such as natural gas or city gas, and water. Supplied. On the other hand, in the combustor 20, combustion air, off-gas, and hydrogen as necessary are supplied for combustion, and in the evaporator 18, the reforming fuel and water are evaporated.

The evaporated reforming fuel is sent to the reactor 22. In the reactor 22, for example, CH ₄ + 2O ₂ → CO ₂ + 2H ₂ O (exothermic reaction), which is an oxidation reaction, and a fuel reforming reaction by methane, oxygen in the air, and water vapor in the reforming fuel. A certain CH ₄ + 2H ₂ O → CO ₂ + 4H ₂ (endothermic reaction) is performed simultaneously (autothermal method).

  As described above, the reformed gas reformed by the reactor 22 is cooled by the cooler 24 and then supplied to the gas-liquid separator 26. The reformed gas from which moisture has been separated by the gas-liquid separator 26 is sent to the reformed gas supply path 46, compressed by the compressor 50, and supplied to the PSA mechanism 48.

  In the PSA mechanism 48, components other than hydrogen are adsorbed in each adsorption tower to purify the fuel gas containing high-concentration hydrogen (hydrogen rich), and this fuel gas is supplied to the fuel gas path 58. The fuel gas is selectively stored in the filling tank 66 and the power generation tank 72 under the action of the compressor 60.

  The fuel gas filled in the power generation tank 72 is supplied to the anode electrode (not shown) of the stationary fuel cell 74 from the fuel gas supply path 76 under the opening action of the valve 78. On the other hand, the compressor 80 is driven to supply air as an oxidant gas to a cathode side electrode (not shown) of the stationary fuel cell 74. For this reason, the stationary fuel cell 74 generates electric power and generates electric power. This electric power is used as a household power source and also used as a system auxiliary power source including the compressor 80.

  On the other hand, in the PSA mechanism 48, off-gas (residual gas) from each adsorption tower is discharged to the off-gas discharge path 52. The offgas discharge path 52 is connected to an offgas flow path 56 via an offgas ejector 54. For this reason, the off-gas discharged to the off-gas discharge path 52 is sent to the combustor 20 through the off-gas discharge air (compressed air) supplied to the off-gas ejector 54. This off gas is used as a combustion fuel for the combustor 20.

  Next, an operation method during a power failure in the household fuel gas purification system 10 will be described below. In the present embodiment, the operation method when a power failure occurs while the household fuel gas purification system 10 is stopped and the operation method when a power failure occurs while the household fuel gas purification system 10 is operating will be described separately.

  First, in the household fuel gas purification system 10 that is stopped, when the start switch is turned on (step S1 in FIG. 2), the process proceeds to step S2, whether or not the external power supply is cut off, that is, a power failure state. It is determined whether or not.

  If it is determined that the external power source is not shut off (NO in step S2), the process proceeds to step S3, and the home fuel gas purification system 10 starts normal startup as described above.

  On the other hand, if it is determined that the external power supply is cut off (YES in step S2), the process proceeds to step S4, and the auxiliary power supply unit 82 is connected under the action of the power supply box 84. The auxiliary power supply 82 is set to a capacity that drives the compressor 80 and the minimum solenoid valve necessary for power generation for only a few minutes.

  Therefore, the cathode compressor 80 is driven by the electric power from the auxiliary power source 82, and air is supplied as an oxidant gas to a cathode side electrode (not shown) of the stationary fuel cell 74. In the stationary fuel cell 74, it is determined whether or not the air discharge pressure reaches the predetermined pressure P1 kPa (step S6), and if the predetermined pressure P1 kPa does not reach even after the predetermined time T1 has elapsed (YES in step S7). ) A failure alarm is issued.

  When the air discharge pressure reaches the predetermined pressure P1 kPa within the predetermined time T1 (YES in step S6), the process proceeds to step S8, and the valve 78 is turned on (opened). Therefore, the fuel gas stored in the power generation tank 72 is supplied to an anode electrode (not shown) of the stationary fuel cell 74 through the fuel gas supply path 76.

  It is determined whether or not the protruding pressure (hydrogen discharge pressure) of the fuel gas supplied to the stationary fuel cell 74 reaches a predetermined pressure P2 kPa (step S9). If the hydrogen discharge pressure does not reach the predetermined pressure P2 kPa within the predetermined time T2 (YES in step S10), a failure alarm is given. On the other hand, when the hydrogen discharge pressure reaches the predetermined pressure P2 kPa within the predetermined time T2 (YES in step S9), the process proceeds to step S11, and power generation of the stationary fuel cell (FC) 74 is started.

  Next, it is determined whether or not the stationary fuel cell 74 is generating electricity normally (steps S12 and S13). If normal power generation is not performed even after the predetermined time T3 has elapsed (YES in step S13), a failure alarm is given, while if normal power generation is started within the predetermined time T3 (in step S12, YES), the process proceeds to step S14. In step S <b> 14, the auxiliary power supply unit 82 is shut off, and the supply of power from the auxiliary power supply unit 82 is stopped.

  When power generation of the stationary fuel cell 74 is started, monitoring of the tank pressure of the power generation tank 72 is started. When the tank pressure becomes equal to or lower than the set pressure P3 kPa (YES in step S15), the process proceeds to step S16, and the operation of the household fuel gas purification system 10 is started. A part of the electric power generated by the power generation of the stationary fuel cell 74 is sent to the auxiliary power supply unit 82 and charged to the auxiliary power supply unit 82.

  Next, it is determined whether or not the supply amount of the reforming fuel is equal to or less than the set amount a (step S17 in FIG. 3). For example, when a power failure occurs due to a disaster or the like, the supply of reforming fuel such as city gas is stopped, so the supply amount of the reforming fuel is lower than the set amount a (YES in step S17). .

  For this reason, it progresses to step S18, and while the fuel gas manufacture by the household fuel gas purification system 10 is stopped, the electric power generation by the stationary fuel cell 74 is continued. The electric power generated by the stationary fuel cell 74 is used as a household power source.

  When the fuel gas stored in the power generation tank 72 decreases and the tank pressure of the power generation tank 72 becomes equal to or lower than the set pressure P3 kPa (YES in step S19), the process proceeds to step S20, and the stationary fuel Power generation by the battery 74 is stopped. The control ECU 86 constantly monitors the supply of external power, and when the supply of external power resumes, the home power supply is switched from the stationary fuel cell 74 to the external power supply.

  Next, a case where a power failure occurs during operation of the household fuel gas purification system 10 will be described with reference to the flowcharts of FIGS. 4 and 5.

  First, it is determined whether or not the external power source is shut off during operation of the household fuel gas purification system 10 (steps S31 and S32). If the external power source is not shut off, the operation of the household fuel gas purification system 10 is continued (step S33), while if it is determined that the external power source is shut off (YES in step S32), step S34 is performed. Then, the auxiliary power supply unit 82 is connected.

  Further, reforming and purification (reforming system) by the household fuel gas purification system 10 is stopped (step S35), electric power is supplied from the auxiliary power source 82 to the compressor 80, and the operation of the compressor 80 is started. (Step S36).

  Thereafter, Steps S37 to S44 are performed in the same manner as Steps S6 to S13 described above, and when the stationary fuel cell 74 generates power and generation of power is started, the auxiliary power supply unit 82 is shut off. (Step S45). Therefore, when the tank pressure of the power generation tank 72 becomes equal to or lower than the set pressure P3 kPa (YES in step S46), the operation of the household fuel gas purification system 10 is started (step S47).

  Hereinafter, step S48 to step S51 are performed in the same manner as step S17 to step S20 described above.

  In this case, in this embodiment, when the stationary fuel cell 74 is not started due to a power failure, the starting power is supplied from the auxiliary power supply unit 82 dedicated to starting up the stationary fuel cell 74. For example, a capacitor is used as the auxiliary power source 82. The capacitor is set to a capacity that can move the minimum solenoid valve necessary for starting the compressor 80 and the stationary fuel cell 74 for only several minutes.

  For this reason, the auxiliary power source 82 itself can be significantly reduced in size and simplified, and the stationary fuel cell 74 can be reliably started up during a power failure. As a result, the household fuel gas purification system 10 as a whole can be easily made compact, and the stationary fuel cell 74 can generate power well and reliably during a power failure.

It is a schematic block diagram of the domestic fuel gas refinement | purification system for enforcing the operating method at the time of the power failure which concerns on embodiment of this invention. FIG. 5 is a front part of a flowchart for explaining an operation method at the time of a power failure in the household fuel gas purification system that is stopped. FIG. It is a latter part of the flowchart. FIG. 6 is a front part of a flowchart for explaining an operation method at the time of a power failure in the domestic fuel gas purification system during operation. It is a latter part of the flowchart. 2 is a schematic configuration explanatory diagram of Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Domestic fuel gas refining system 12 ... Reforming part 14 ... Purifying part 16 ... Storage part 18 ... Evaporator 22 ... Reactor 38a, 38b, 64, 70, 78 ... Valve 48 ... PSA mechanism 60, 80 ... Compressor 66 ... Filling tank 72 ... Power generation tank 74 ... Stationary fuel cell 76 ... Fuel gas supply path 82 ... Auxiliary power supply unit 84 ... Power supply box 86 ... Control ECU

Claims (3)

A reforming unit for reforming a hydrogen-containing fuel to obtain a reformed gas; a purifying unit for purifying a hydrogen-rich fuel gas by removing unnecessary substances from the reformed gas; and a storage unit for storing the fuel gas. An operation method at the time of a power failure in a fuel gas production power generation system comprising: a power generation unit that generates power by being supplied with the fuel gas; and an auxiliary power supply unit that is connected to the power generation unit and supplies only power for starting the power generation unit Because
Detecting whether it is in a power outage state;
Supplying the fuel gas from the storage unit to the power generation unit using the power of the auxiliary power unit when the power failure state is detected, and supplying an oxidant gas to the power generation unit;
A step of stopping power supply from the auxiliary power supply unit after power generation by the power generation unit is started, while supplying power from the power generation unit;
An operation method at the time of a power failure in a fuel gas production power generation system. The operation method according to claim 1, wherein a step of detecting a remaining amount of fuel gas remaining in the storage unit;
When the remaining amount of fuel gas reaches a specified amount or less, starting the operation of the reforming unit and the purification unit;
An operation method at the time of a power failure in a fuel gas production power generation system. 3. The operation method according to claim 1, wherein when the supply amount of the hydrogen-containing fuel to the reforming unit reaches a specified amount or less, the operation of the reforming unit and the purification unit is stopped while the power generation The process of continuing power generation by the department,
A step of stopping power generation by the power generation unit when the remaining amount of fuel gas remaining in the storage unit reaches a specified amount or less;
An operation method at the time of a power failure in a fuel gas production power generation system.

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