JP2018195377A - Fuel battery and composite power generation system - Google Patents

Abstract

To achieve effective cooling inside a power generation chamber even if a carbon hydride-based gas not containing a sufficient amount of gas capable of modifying water vapor is used as a fuel.SOLUTION: A fuel battery comprises: an SOFC cartridge 203 into which a coal gasification gas which contains a gas capable of modifying water vapor at 10 vol.% or less is introduced as a fuel, and which has a plurality of cell stacks 101 with fuel battery cells formed therein; an adiabatic wall part 228 for enclosing the SOFC cartridge 203 to form a power generation chamber 215; and a heat-conducting tube 3 disposed in the power generation chamber 215, into which a cooling water or water vapor is led.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell and a combined power generation system in which a hydrocarbon-based gas (for example, coal gasification gas) that does not sufficiently contain a gas capable of steam reforming such as methane is used as a fuel.

  There is known a fuel cell that generates electric power by chemically reacting a fuel gas and an oxidizing gas. Among these, a solid oxide fuel cell (SOFC) is a fuel cell that uses ceramics such as zirconia ceramics as an electrolyte and is operated using city gas or natural gas as fuel. Such an SOFC is known as a high-efficiency high-temperature fuel cell that is versatile and has a high operating temperature of about 700 to 1000 ° C. in order to increase ionic conductivity. Such a SOFC can be combined with an internal combustion engine such as a gas turbine to form a combined power generation system. In the combined power generation system, compressed air discharged from the compressor is supplied to the SOFC air electrode, and high-temperature exhaust fuel gas discharged from the SOFC is supplied to the combustor of the gas turbine and burned. Power generation with high power generation efficiency is possible by rotating the turbine with the generated combustion gas.

During power generation of the SOFC, the fuel cell formed by the solid electrolyte membrane, the fuel electrode, and the air electrode generates heat. The fuel cell preferably generates power in a preset temperature range based on viewpoints such as power generation efficiency and durability.
When city gas or natural gas based on methane is used, the internal reforming of methane in the fuel cell can be performed using the catalytic action of the fuel electrode. In the internal reforming, a mixed gas of methane (CH ₄ ) and water vapor is reacted to reform into hydrogen (H ₂ ) and carbon monoxide (CO) in a fuel cell. Since this internal reforming is an endothermic reaction, it plays the role of cooling the fuel cell.

Patent Document 1 discloses a reformer that reforms a fuel gas, which is a gasification gas supplied from a gasification furnace, using water vapor sent from a moisture supply device.
In patent document 2, in order to obtain the steam used for steam reforming, an invention is disclosed in which a heat transfer tube is arranged inside a heat insulating material surrounding a power generation unit and water is supplied into the heat transfer tube to generate steam. Yes.

JP 2004-39449 A JP-A-2015-84300 ([0047]-[0048], FIG. 3)

  However, when a gas that contains almost no methane, such as coal gasification gas, is used as the fuel, the endothermic heat generated by steam reforming cannot be used. It is necessary to supply it to the power generation unit more than that. Alternatively, it is necessary to cool and recycle a large amount of exhaust air after power generation to maintain the temperature of the power generation unit, but this requires power for supplying air.

  The present invention has been made in view of such circumstances, and even when a hydrocarbon-based gas that does not sufficiently contain a gas capable of steam reforming is used as a fuel, the power generation chamber is effective. An object of the present invention is to provide a fuel cell and a combined power generation system that can be cooled to each other and improve power generation efficiency.

  In order to solve the above problems, the fuel cell and the combined power generation system of the present invention employ the following means.

  A fuel cell according to the present invention is a cell stack group in which a plurality of cell stacks each having a fuel cell formed therein are arranged by introducing a hydrocarbon-based gas whose gas capable of steam reforming is 10 vol% or less as a fuel. And a heat insulating wall portion that houses the cell stack group and forms a power generation chamber, and a heat transfer tube that is disposed in the power generation chamber and into which cooling water or water vapor is guided.

Since the hydrocarbon-based gas in which the gas capable of steam reforming (methane, propane or the like) is 10 vol% or less is used as a fuel, the endothermic reaction due to steam reforming of methane or the like cannot be used. Therefore, by arranging a heat transfer tube through which cooling water or water vapor is guided inside the power generation chamber, the power generation chamber is cooled to suppress an increase in temperature in the power generation chamber. This eliminates the need to supply a large amount of oxidizing gas (for example, air) to cool the power generation chamber.
Examples of the “hydrocarbon gas whose gas capable of steam reforming is 10 vol% or less” include coal gasification gas.

  Furthermore, in the fuel cell of the present invention, a temperature sensor that measures the temperature in the power generation chamber, a flow rate control valve that controls the flow rate of the cooling water or water vapor that flows in the heat transfer tube, and the temperature sensor that is obtained from the temperature sensor. And a control unit that controls the flow rate control valve based on temperature.

  Since the flow control valve is controlled based on the temperature obtained from the temperature sensor, the amount of heat absorbed in the heat transfer tube can be adjusted to control the temperature in the power generation chamber to a desired value.

  Furthermore, the fuel cell of the present invention is a cell stack in which a plurality of cell stacks in which fuel cell cells are formed are provided by introducing hydrocarbon-based gas whose gas capable of steam reforming is 10 vol% or less as fuel. There are a plurality of groups and cell stack groups, and between each of the cell stack groups, a heat transfer tube through which cooling water or water vapor is guided is provided.

  Since the heat transfer tubes are arranged between the cell stack groups, the temperature distribution in the cell stack groups can be relaxed. Thereby, the current imbalance between cell stacks can be improved and more stable operation can be realized.

  Furthermore, the fuel cell of the present invention includes a water vapor supply pipe that is connected to the heat transfer pipe and guides water vapor to the hydrocarbon gas.

  By introducing water vapor into the hydrocarbon gas through the water vapor supply pipe, it is possible to suppress the precipitation of carbon in the hydrocarbon gas.

  Furthermore, in the fuel cell of the present invention, a boiler connected to the heat transfer tube, a cooling water supply path for supplying the cooling water to the heat transfer tube, and steam generated by the boiler to the heat transfer tube are supplied. A steam supply path is provided, and the cooling water supply path and the steam supply path can be switched.

By connecting a boiler to the heat transfer tube, steam generated by the boiler can be supplied to the heat transfer tube. Thereby, the temperature in the power generation chamber can be raised when the fuel cell is started.
By switching between the cooling water supply path and the steam supply path, the steam guided from the boiler is supplied to the heat transfer pipe at the time of startup, and the cooling water is supplied to the heat transfer pipe at the time of power generation. Thereby, the heat transfer tube can be used not only for cooling but also for heating.

  Furthermore, the fuel cell of the present invention includes a cooling water flow rate control means for controlling the flow rate of the cooling water flowing through the cooling water supply path, and a steam flow rate control means for controlling the flow rate of the steam flowing through the steam supply path. Yes.

  At startup, the steam guided from the boiler by the steam flow control means is supplied to the heat transfer tube, and the cooling water is supplied by the cooling water flow control means as necessary. During power generation, the cooling water flow rate control means and / or the steam flow rate control means supplies cooling water or steam to the heat transfer tubes. Thereby, the temperature of a power generation chamber can be set to a desired value at the time of start-up and power generation.

  Further, the fuel cell of the present invention is a cell stack in which a plurality of cell stacks in which fuel cells are formed are introduced as a hydrocarbon-based gas whose gas capable of steam reforming is 10 vol% or less. A water supply means for supplying water or steam between each of the cell stacks and the heat insulation wall disposed in the power generation chamber; And.

Since the hydrocarbon-based gas in which the gas capable of steam reforming (methane, propane or the like) is 10 vol% or less is used as a fuel, the endothermic reaction due to steam reforming of methane or the like cannot be used. Therefore, water supply means for supplying water or water vapor is provided between the cell stack and the heat insulating wall portion, and the power generation chamber is cooled to suppress an increase in temperature in the power generation chamber. This eliminates the need to supply a large amount of oxidizing gas (for example, air) to cool the power generation chamber.
Examples of the “hydrocarbon gas whose gas capable of steam reforming is 10 vol% or less” include coal gasification gas.

  Furthermore, in the fuel cell of the present invention, the water supply means is a water spray pipe disposed between each cell stack and the heat insulating wall.

Since water is supplied from the water spray pipe between the cell stack and the heat insulating wall, the power generation chamber can be effectively cooled by the latent heat of vaporization of water.
The water supplied to the water spray pipe may be reused by cooling and condensing the gas (for example, exhaust air) mixed with the spray water and discharged from the power generation chamber.

  Furthermore, the fuel cell of the present invention is a cell stack in which a plurality of cell stacks in which fuel cell cells are formed are provided by introducing hydrocarbon-based gas whose gas capable of steam reforming is 10 vol% or less as fuel. There are a plurality of groups and cell stack groups, and water spray tubes for supplying water or water vapor are provided between the cell stack groups.

  Since the water spray tube is arranged between the cell stack groups, the temperature distribution in the cell stack group can be relaxed. Thereby, the current imbalance between cell stacks can be improved and more stable operation can be realized.

  The fuel cell of the present invention further includes an oxidizing gas supply pipe that supplies an oxidizing gas between each of the cell stacks and the heat insulating wall, and the water supply means flows through the oxidizing gas supply pipe. It is a humidifying spray that humidifies oxidizing gas.

By humidifying the oxidizing gas flowing in the oxidizing gas supply pipe by the humidifying spray, the heat capacity of the oxidizing gas supplied between the cell stack and the heat insulating wall can be increased and the cooling capacity can be improved.
When the oxidizing gas supply pipe is connected to the compressor of the gas turbine, the oxidizing gas introduced from the compressor is at a high temperature, so the water supplied from the humidifying spray is the oxidizing gas. It becomes water vapor easily by sensible heat.
Moreover, the water supplied to the humidifying spray may be reused by cooling and condensing the oxidizing gas (for example, exhaust air) discharged from the power generation chamber.

  The combined power generation system of the present invention is described in any one of claims 1 to 7, wherein a gasification furnace for gasifying a carbon-containing solid fuel and a gasification gas gasified in the gasification furnace are led. A fuel cell, a gas turbine that generates rotational power using exhaust fuel gas and exhaust oxidizing gas exhausted from the fuel cell, a gas turbine generator that is driven by the rotational power of the gas turbine and generates power An exhaust gas boiler that generates steam from the exhaust gas discharged from the gas turbine, a steam turbine that generates rotational power by the steam generated by the exhaust gas boiler, and a steam turbine that is driven by the rotational power of the steam turbine to generate electric power And a generator.

  Even when a hydrocarbon-based gas that does not sufficiently contain a gas capable of steam reforming is used as a fuel, it is not necessary to supply a large amount of oxidizing gas (for example, air) to cool the power generation chamber.

1 is a schematic configuration diagram illustrating a combined power generation system according to a first embodiment. It is the top view which showed the inside of the SOFC module of 2nd Embodiment. It is the side view which showed the inside of the SOFC module of 2nd Embodiment. It is the front view which showed the heat-transfer panel part. It is the schematic block diagram which showed the combined power generation system which concerns on 3rd Embodiment of this invention. It is the top view which showed the inside of the SOFC module of 4th Embodiment. It is the side view which showed the inside of the SOFC module of 4th Embodiment. It is the schematic block diagram which showed the combined power generation system which concerns on 5th Embodiment of this invention.

  Embodiments according to the present invention will be described below with reference to the drawings.

[First Embodiment]
The first embodiment of the present invention will be described below.
In the following, for convenience of explanation, the positional relationship of each component is specified using the expressions “upper” and “lower” on the basis of the paper surface, but this is not necessarily limited to the vertical direction. For example, the upward direction on the paper surface may correspond to the downward direction in the vertical direction. Moreover, you may respond | correspond to the horizontal direction where the up-down direction in a paper surface goes orthogonally to a perpendicular direction.
<Composite power generation system>
FIG. 1 shows a combined power generation system 1 using a SOFC module 201. The combined power generation system 1 of the present embodiment is an integrated coal gasification fuel cell combined cycle (IGFC) system that performs combined power generation using fuel obtained by gasifying coal (carbon-containing solid fuel). It is. The carbon-containing solid fuel to be gasified in the gasification furnace is not limited to the coal of this embodiment. For example, biomass fuel such as thinned wood, waste wood, driftwood, grass, waste, sludge, tires, etc. It is also applicable to.

  The combined power generation system 1 includes power generation performed by the SOFC module 201 by supplying coal gasification gas obtained by gasifying coal in a gasification furnace (not shown) and refined by a gas purification unit (not shown) as fuel gas, Rotation of a steam turbine 51 that operates by introducing steam generated by using power generated by a gas turbine generator 40G driven by the rotational power of the turbine 40 and exhaust heat of combustion exhaust gas discharged from the gas turbine 40 It is configured to perform combined power generation in combination with power generation performed by a steam turbine generator 51G driven by power.

  The coal gasification gas gasified in the gas furnace is subjected to various treatments such as desulfurization required in the gas refining unit, and the fuel gas (coal gasification gas) used for the operation of the SOFC module 201 and the gas turbine 40 Become. Coal gasification gas is mainly composed of hydrogen and carbon monoxide and contains almost no methane.

  The coal gasification gas is supplied to the SOFC module 201 through the fuel gas supply pipe 207 shown in FIG. The exhaust fuel gas after being used for power generation by the SOFC module 201 is guided to the combustor 41 of the gas turbine 40 through the fuel gas discharge pipe 209 shown in FIG.

  An oxidizing gas supply pipe 208 is provided between the SOFC module 201 and the compressor 42 of the gas turbine 40. The air compressed by the compressor 42 is guided to the SOFC module 201 as an oxidizing gas through the oxidizing gas supply pipe 208. The exhaust oxidizing gas after being used for power generation in the SOFC module 201 passes through the oxidizing gas discharge pipe 210 and is guided to the combustor 41 of the gas turbine 40.

  The gas turbine 40 includes a combustor 41, a compressor 42, and a turbine 43. The combustor 41 combusts the exhaust oxidizing gas guided from the SOFC module 201 via the oxidizing gas discharge pipe 210 and the exhaust fuel gas guided from the SOFC module 201 via the fuel gas exhaust pipe 209 to generate high temperature and pressure. Of combustion exhaust gas. When this combustion exhaust gas is supplied to the turbine 43, the turbine 43 is rotated to generate a shaft output. The shaft output generated by the turbine 43 drives the gas turbine generator 40G connected coaxially. A part of the shaft output of the gas turbine 40 is used for the continuous operation of the compressor 42.

  A regenerative heat exchanger 45 is provided between the combustion exhaust gas discharge pipe 44 on the outlet side of the turbine 43 and the oxidizing gas supply pipe 208 on the outlet side of the compressor 42. Heat is recovered from the combustion exhaust gas discharged from the turbine 43 by the regenerative heat exchanger 45 and the air compressed by the compressor 42 is heated.

  The combustion exhaust gas after heat recovery by the regenerative heat exchanger 45 still has a sufficient amount of heat and is supplied to the HRSG (exhaust heat recovery boiler: exhaust gas boiler) 50 via the combustion exhaust gas exhaust pipe 44. . In the HRSG 50, the combustion exhaust gas supplied from the gas turbine 40 and the water guided from the condensate pump 53 are subjected to heat exchange to generate steam.

  The steam generated by the HRSG 50 is supplied to the steam turbine 51 and is generated by the steam turbine generator 51G using the steam turbine 51 as a drive source. The steam after finishing the work in the steam turbine 51 is led to the condenser 54 to be condensed and liquefied. The condensate liquefied by the condenser 54 is guided again to the HRSG 50 by the condensate pump 53.

  The combustion exhaust gas after passing through the HRSG 50 passes through the combustion exhaust gas exhaust pipe 44 and is released from the chimney 52 to the atmosphere.

<Cooling structure of power generation room>
Next, the cooling structure of the power generation chamber 215 of the SOFC module 201 will be described.
As shown in FIG. 1, a SOFC cartridge 203 is provided in a module container 229 that is a pressure container. A plurality of SOFC cartridges 203 are provided in the module container 229, but only one SOFC cartridge 203 is shown in FIG. 1 for easy understanding.

  The SOFC cartridge 203 includes a heat insulating wall 228 and a plurality of cell stacks 101 arranged at predetermined intervals (hereinafter, the plurality of arranged cell stacks are referred to as “cell stack group”). . A region surrounded by the heat insulating wall 228 is a power generation chamber 215. A heat transfer tube 3 through which water or water vapor flows is provided in the region where the oxidizing gas flows in the power generation chamber 215, that is, between the cell stack 101 and the heat insulating wall 228. A supply pipe (steam supply path) 5 a for supplying cooling water or steam is connected to the upstream side of the heat transfer tube 3.

  The heat insulating wall 228 covers the side periphery of the power generation chamber 215 so as to form the power generation chamber 215, and plays a role of guiding the flow of the oxidizing gas flowing in the power generation chamber 215. Thereby, the battery reaction can be effectively performed by causing the oxidizing gas to flow preferentially into the power generation chamber 215, and the heat generated by the battery reaction by the oxidizing gas can be efficiently cooled. The oxidizing gas supplied to the battery reaction in the power generation chamber is discharged out of the module through the oxidizing gas discharge pipe 210. The heat insulating wall 228 does not seal the inside of the power generation chamber 215, and a part of the oxidizing gas flows out of the power generation chamber 215. Therefore, the inside of the module container 229 becomes high temperature due to the oxidizing gas flowing out of the power generation chamber 215 from the heat insulating wall 228 and the radiant heat from the heat insulating wall 228.

  As shown in FIG. 1, the heat transfer tubes 3 may be arranged on the side of the cell stack group. However, one or several cell stacks 101 arranged inside the cell stack group, that is, arranged at a predetermined interval, are arranged. You may make it remove and arrange | position the heat exchanger tube 3 in the position. Thereby, the space efficiency in the power generation chamber 215 can be improved.

  An auxiliary boiler 8 is provided on the upstream side of the supply pipe 5a. The auxiliary boiler 8 operates by receiving the supply of water from the feed water pump 6 when the SOFC module 201 is activated. The steam generated in the auxiliary boiler 8 is guided to the heat transfer tube 3 to raise the temperature in the power generation chamber 215. The upstream side of the auxiliary boiler 8 is connected to a condensate pump 53 via a feed water flow rate control valve (steam flow rate control means) 7 and a condensate supply pipe 5. Therefore, the condensate discharged from the condensate pump 53 is guided not only to the HRSG 50 but also to the heat transfer pipe 3 via the condensate supply pipe 5.

  A cooling water supply pipe (cooling water supply path) 9 is provided so as to bypass the auxiliary boiler 8 and the feed water flow rate control valve 7. The cooling water supply pipe 9 is provided with a cooling water flow rate control valve 10. The opening degree of the cooling water flow rate control valve 10 is controlled by the control unit 12 based on the temperature obtained by the temperature sensor 11 that measures the temperature in the power generation chamber 215. The temperature sensor 11 is, for example, a thermocouple, and is inserted from the outside of the power generation chamber 215 so that the temperature sensing unit is located inside the power generation chamber 215.

  A water supply pump 6 is connected to a midway position of the condensate supply pipe 5. The feed water pump 6 is for replenishing water when the SOFC module 201 is started up, or for supplementing steam supplied to the fuel system to prevent carbon deposition.

  The control unit 12 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is preinstalled in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

  A steam discharge pipe 15 is connected to the downstream side of the heat transfer pipe 3. A downstream side of the steam discharge pipe 15 is connected to a steam inlet pipe 56 on the upstream side of the steam turbine 51. Thereby, the steam discharged from the heat transfer tube 3 is guided to the steam turbine 51. The steam discharge pipe 15 may be connected to the HRSG 50 so that the steam is superheated by the HRSG 50.

  An extraction pipe (steam supply pipe) 16 connected to the fuel gas supply pipe 207 is provided in the middle of the steam discharge pipe 15. The extraction pipe 16 is provided with an extraction flow control valve 17 whose opening degree is controlled by the control unit 12 in accordance with the composition of the coal gasification gas. A part of the steam flowing through the steam discharge pipe 15 is guided to the fuel gas supply pipe 207 via the extraction pipe 16 so that carbon in the coal gasification gas flowing through the fuel gas supply pipe 207 is prevented from being precipitated. It has become.

Next, a heating method and a cooling method for the power generation chamber 215 of the SOFC module 201 having the above configuration will be described.
When the SOFC module 201 is activated, water supply from the condensate pump 53 is not performed, and water is supplied from the water supply pump 6 to the auxiliary boiler 8. At this time, the water supply flow rate control valve 7 is opened and the cooling water flow rate control valve 10 is closed by a command from the control unit 12. The feed water guided to the auxiliary boiler 8 is heated by the auxiliary boiler 8 into steam, and is guided to the heat transfer tube 3 through the condensate supply pipe 5. When steam passes through the heat transfer tube 3, the power generation chamber 215 is heated. Thereby, the temperature rise until the SOFC module 201 starts power generation is added.

Moreover, after the SOFC module 201 starts power generation as described later, the heat transfer tube 3 is used to cool the temperature in the power generation chamber 215 to a desired value. As the steam at this time, it is preferable to use steam obtained by partially extracting the outlet steam of the steam turbine 51 through the outlet steam extraction pipe 57 (see * in FIG. 1). The outlet steam extraction pipe 57 is provided with an extraction steam flow rate control valve 57 a whose opening degree is controlled by the control unit 12. Further, the temperature inside the power generation chamber 215 may be controlled by controlling the opening degree of the feed water flow rate control valve 7 provided on the upstream side of the auxiliary boiler 8 to adjust the amount of steam introduced from the auxiliary boiler 8. By using steam, it is possible to avoid a sudden change in temperature at the start of cooling or when the cooling water is overcooled (temperature drop).
For example, by using the extraction steam flow rate control valve 57a, the feed water flow rate control valve 7, and the cooling water flow rate control valve 10, the following operation becomes possible. Before starting the SOFC module 201, heating is performed only with steam from the auxiliary boiler 8, and before and after power generation by the SOFC module 201, the steam is gently cooled with steam from the auxiliary boiler 8 and the extracted steam from the steam turbine 51. While the operating load of the SOFC module 201 is low, cooling is performed with cooling water and the extracted steam of the steam turbine 51, and when the operating load of the SOFC module 201 becomes higher than a predetermined load, cooling is performed only with cooling water.

  When power generation is performed after the inside of the power generation chamber 215 is heated to the power generation start temperature, the opening degree of the cooling water flow rate control valve 10 is set by the control unit 12 based on the temperature in the power generation chamber 215 measured by the temperature sensor 11. Be controlled. Thereby, the temperature in the power generation chamber 215 is controlled to be a desired value. The cooling water is led from the condensate pump 53 which has already been started, and led to the heat transfer pipe 3 through the cooling water supply pipe 9 and the supply pipe 5a.

  The superheated steam that has evaporated in the power generation chamber 215 through the heat transfer tube 3 is guided to the inlet side of the steam turbine 51 through the steam discharge pipe 15. Therefore, the superheated steam generated in the heat transfer pipe 3 is condensed in the condenser 54 after working in the steam turbine 51 and reused.

  A part of the superheated vapor evaporated through the heat transfer pipe 3 is led to the fuel gas supply pipe 207 through the extraction pipe 16. By adding water vapor to the coal gasification gas, it becomes possible to suppress the precipitation of carbon. The amount of water vapor added to the coal gasification gas is controlled to a desired value by changing the opening degree of the extraction flow control valve 17 by the control unit 12 according to the composition and flow rate of the coal gasification gas.

According to embodiment mentioned above, there exist the following effects.
Since the SOFC module 201 uses coal gasification gas containing almost no gas capable of steam reforming (such as methane or propane) as a fuel, the endothermic reaction due to steam reforming of methane or the like cannot be used. Therefore, by arranging the heat transfer pipe 3 into which cooling water or water vapor is guided in the region where the oxidizing gas flows in the power generation chamber 215, the power generation chamber 215 is cooled, and the temperature in the power generation chamber 215 is increased. We decided to suppress it. Thereby, it is not necessary to supply a large amount of oxidizing gas (for example, air) in order to cool the inside of the power generation chamber 215.

  By mixing the superheated steam evaporated in the heat transfer tube 3 by the extraction pipe 16 with the coal gasification gas, it is possible to suppress the precipitation of carbon in the coal gasification gas.

  At the time of start-up, the feed water flow rate control valve 7 is opened so that steam guided from the auxiliary boiler 8 is supplied to the heat transfer tube 3, and at the time of power generation, the feed water flow rate control valve 7 is closed and cooling water or steam is supplied to the heat transfer tube 3. I made it. Thus, the heat transfer tube 3 can be used not only for cooling the SOFC module 201 but also for raising the temperature at startup.

  Further, the temperature of the fluid supplied to the heat transfer pipe 3 is controlled by controlling the extraction steam flow control valve 57 a provided in the outlet steam extraction pipe 57 and / or the feed water flow control valve 7 provided on the upstream side of the auxiliary boiler 8. It was decided to. As a result, it is possible to avoid excessive cooling (temperature drop) when the cooling water is flowed or a sudden change in temperature at the start of cooling.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in the cooling method, and the other is the same. Therefore, in the following description, the same components as those in the first embodiment are denoted by the same reference numerals, the description thereof is omitted, and only differences from the first embodiment will be described.

  2 and 3 show the heat transfer tube 3 arranged in the SOFC module 201 surrounded by the module container 229. In the SOFC module 201, a plurality (six in the example shown in the figure) of SOFC cartridges 203 each having a cell stack group in which a plurality of cell stacks 101 are arranged at predetermined intervals are provided. It has been.

  As shown in FIG. 2 in plan view of the SOFC module 201, the heat transfer tube 3 is provided with the introduction portion 3 a below the one side of each SOFC cartridge 203 along the longitudinal direction of the SOFC module 201. Under the other side of each SOFC cartridge 203, a lead-out portion 3b of the heat transfer tube 3 is provided along the longitudinal direction of the SOFC module 201. Between the introduction part 3a and the lead-out part 3b of the heat transfer tube 3, a heat transfer panel part 3c is provided. The heat transfer panel unit 3 c is disposed between the SOFC cartridges 203. However, the heat transfer panel portions 3c are not provided at both ends of the SOFC module 201 in the longitudinal direction (horizontal direction in FIGS. 2 and 3). This is because heat is released to the outside of the SOFC module 201 at both ends of the SOFC module 201.

  As shown in FIG. 3 which is a side view of the SOFC module 201, the heat transfer panel portion 3c is erected upward from the lower side and has a height corresponding to the height of the SOFC cartridge 203.

  As shown in FIG. 4, the heat transfer panel portion 3 c is a plate-like body having a rectangular plane, and the main body portion 3 d of the heat transfer tube 3 is provided to meander. The heat transfer panel 3c is configured such that an insulator (for example, ceramics) covers at least the outer surface so as not to conduct when it contacts the SOFC cartridge 203.

  2 and 3 show a high temperature region H indicated by a two-dot chain line. The high temperature region H is a region where heat is not easily radiated to the outside, and is generated at the center (see FIG. 2) when the SOFC cartridge 203 is viewed in plan and at the center (see FIG. 3) when viewed from the side. 2 and 3, the high temperature region H is shown for one SOFC cartridge 203, but the high temperature region H is similarly generated at the center for the other SOFC cartridges 203. Further, as described in the first embodiment, the inside of the module container 229 is heated to a high temperature by the oxidizing gas flowing out of the power generation chamber 215 from the heat insulating wall 228 (see FIG. 1) and the radiation of the heat insulating wall 228. Become.

According to embodiment mentioned above, there exist the following effects.
Since the SOFC module 201 uses coal gasification gas containing almost no gas capable of steam reforming (such as methane or propane) as a fuel, the endothermic reaction due to steam reforming of methane or the like cannot be used. In view of this, the heat transfer panel 3c is arranged between the SOFC cartridges 203 to suppress an increase in temperature in the region between the SOFC cartridges 203 and thus in the SOFC cartridge 203 (that is, in the power generation chamber 215). Thereby, it is not necessary to supply a large amount of oxidizing gas (for example, air) in order to cool the inside of the power generation chamber 215.

  Since the heat transfer panel 3c is arranged between the SOFC cartridges 203, the temperature distribution in the SOFC cartridge 203 can be relaxed. Thereby, the current imbalance between the cell stacks 101 can be improved, and more stable operation can be realized.

  In addition, you may combine this embodiment with 1st Embodiment which has arrange | positioned the heat exchanger tube in the power generation chamber 215. FIG.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. The present embodiment is different from the first embodiment in the cooling method in the power generation chamber 215 and the other is the same. Therefore, in the following description, the same components as those in the first embodiment are denoted by the same reference numerals, the description thereof is omitted, and only differences from the first embodiment will be described.

  As shown in FIG. 5, a water spray pipe (water supply means) 20 is provided in the power generation chamber 215. Cooling water is injected from the water spray pipe 20 into the region where the oxidizing gas in the power generation chamber 215 flows. The inside of the power generation chamber 215 is cooled by the injected cooling water.

  The steam from which the cooling water has evaporated in the power generation chamber 215 is guided to the combustor 41 through the oxidizing gas discharge pipe 210 together with the oxidizing gas. Then, the steam derived from the cooling water passes through the turbine 43, passes through the HRSG 50 together with the combustion exhaust gas, and is guided to the cooler 21 provided in the combustion exhaust gas discharge pipe 44. In the cooler 21, the combustion exhaust gas is cooled by cooling water or the like (not shown). When the combustion exhaust gas is cooled by the cooler 21, the moisture in the combustion exhaust gas is condensed and collected as condensed water. The condensed water passes through the condensate supply pipe 5 and is guided again to the water spray pipe 20 by the circulation pump 22.

According to this embodiment, there exist the following effects.
Since water is supplied from the water spray pipe 20 to the region where the oxidizing gas flows in the power generation chamber 215, the interior of the power generation chamber 215 can be effectively cooled by the latent heat of vaporization of water.

  Since the condensed water condensed in the cooler 21 that cools the combustion exhaust gas is reused as the cooling water, the amount of water used can be reduced.

  In this embodiment, the cooling water is injected from the water spray pipe 20, but the steam partially extracted from the outlet of the steam turbine 51 (see * in FIG. 5) is injected as cooling steam. It is also good. In this case, although evaporative latent heat cannot be used like cooling water, since water vapor | steam with a larger heat capacity than air can be injected, there exists an advantage that the air input amount for cooling can be reduced.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. This embodiment is cooled by using a water spray tube as in the third embodiment, but the third embodiment is different in that the water spray tube is arranged between the SOFC cartridges 203 as in the second embodiment. And different. Therefore, in the following description, the same components as those in the first embodiment to the third embodiment are denoted by the same reference numerals, the description thereof is omitted, and only differences from the first embodiment to the third embodiment will be described.
6 and 7 show a water spray pipe (water supply means) 20 arranged in the SOFC module 201. FIG. The cooling water is guided into the SOFC module 201 from the introduction part 20a, and is sprayed toward the SOFC cartridge 203 from a plurality of water spray pipes 20 standing upward. The water spray tube 20 is disposed between the SOFC cartridges 203. Water is preferably jetted to the vicinity of the high temperature region H in the center of each SOFC cartridge 203.

According to this embodiment, there exist the following effects.
Since the water spray pipe 20 is provided between the SOFC cartridges 203 and water is supplied from the water spray pipe 20, the region between the SOFC cartridges 203 and the inside of the SOFC cartridge 203 (that is, inside the power generation chamber 215) by the latent heat of vaporization of water. Can be effectively cooled.

  Since the water spray tube 20 is arranged between the SOFC cartridges 203, the temperature distribution in the SOFC cartridge 203 can be relaxed. Thereby, the current imbalance between the cell stacks 101 can be improved, and more stable operation can be realized.

  In addition, you may combine this embodiment with 3rd Embodiment which has arrange | positioned the water spray pipe | tube in the power generation chamber 215. FIG.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIG. The present embodiment is different from the first to fourth embodiments in the cooling method in the power generation chamber 215 and the other is the same. Therefore, in the following description, the same components as those in the first embodiment to the fourth embodiment are denoted by the same reference numerals, the description thereof is omitted, and only differences from the first embodiment to the fourth embodiment will be described.

  As shown in FIG. 8, the humidifying spray 30 is provided in the oxidizing gas supply pipe 208. The humidifying spray 30 injects the water guided from the circulation pump 31 into the compressed air flowing through the oxidizing gas supply pipe 208 to humidify it.

  The circulation pump 31 is provided in the water supply pipe 32. A feed water flow rate control valve 33 is provided on the outlet side of the circulation pump 31. The opening of the feed water flow control valve 33 is controlled by the control unit 12 based on the temperature in the power generation chamber 215 measured by the temperature sensor 11. A circulating water pipe 34 is connected to the upstream side of the circulation pump 31. The condensed water condensed in the cooler 21 is guided by the circulating water pipe 34.

  Although not shown, the auxiliary boiler 8 is provided in parallel with the water supply pipe 32 as shown in FIGS. 1 and 5, and the steam from the auxiliary boiler 8 is supplied to the oxidizing gas supply pipe 208 and cooled until before starting. It may be used not only for temperature increase but also for temperature increase at startup.

According to this embodiment, there exist the following effects.
By humidifying the air flowing in the oxidizing gas supply pipe 208 by the humidifying spray 30, the heat capacity of the air supplied to the power generation chamber 215 can be increased and the cooling capacity can be improved. Thereby, the amount of air input for cooling can be reduced.

  Since the air guided from the compressor 42 and heated by the regenerative heat exchanger 45 has a high temperature, the water supplied from the humidifying spray 30 can be easily converted into water vapor by the sensible heat of the air.

  Since the condensed water condensed in the cooler 21 that cools the combustion exhaust gas is reused as the water used in the humidifying spray 30, the amount of water used can be reduced.

  In each of the above-described embodiments, the coal gasification gas is described as an example of the fuel gas supplied to the SOFC module 201. However, the present invention is not limited to this, and the endothermic reaction by the reforming action is effective. Any hydrocarbon-based gas in which the amount of gas that cannot be used for gas, specifically, gas that can be steam reformed (methane, propane, etc.) is 10 vol% or less may be used.

DESCRIPTION OF SYMBOLS 1 Combined power generation system 3 Heat transfer pipe 3a Introducing part 3b Deriving part 3c Heat transfer panel part 5 Condensate supply pipe 5a Supply pipe (steam supply path)
6 Water supply pump 7 Water supply flow control valve (steam flow control means)
8 Auxiliary boiler 9 Cooling water supply piping (cooling water supply route)
10 Cooling water flow rate control valve (cooling water flow rate control means)
DESCRIPTION OF SYMBOLS 11 Temperature sensor 12 Control part 15 Steam discharge piping 16 Extraction piping (steam supply pipe)
17 Extraction flow control valve 20 Water spray pipe (water supply means)
21 Cooler 22 Circulating pump 30 Humidification spray 31 Circulating pump 32 Feed water piping 33 Feed water flow rate control valve 34 Circulating water piping 40 Gas turbine 40G Gas turbine generator 41 Combustor 42 Compressor 43 Turbine 44 Combustion exhaust gas exhaust pipe 45 Regenerative heat exchanger 50 HRSG (exhaust gas boiler)
51 Steam Turbine 51G Steam Turbine Generator 52 Chimney 53 Condensate Pump 54 Condenser 56 Steam Inlet Pipe 57 Outlet Steam Extraction Pipe 57a Extraction Steam Flow Control Valve 101 Cell Stack 201 SOFC Module (Fuel Cell)
203 SOFC cartridge (cell stack group)
207 Fuel gas supply pipe 208 Oxidizing gas supply pipe 209 Fuel gas discharge pipe 210 Oxidizing gas discharge pipe 215 Power generation chamber 228 Thermal insulation wall 229 Module container H High temperature region

Claims (11)

A cell stack group in which a plurality of cell stacks in which fuel gas is formed and a hydrocarbon-based gas in which a gas capable of steam reforming is 10 vol% or less is led as a fuel;
A heat insulating wall that houses the cell stack group and forms a power generation chamber;
A heat transfer pipe disposed in the power generation chamber and into which cooling water or water vapor is guided;
A fuel cell comprising: A temperature sensor for measuring the temperature in the power generation chamber;
A flow rate control valve for controlling the flow rate of the cooling water or water vapor flowing in the heat transfer tube;
A control unit for controlling the flow rate control valve based on the temperature obtained from the temperature sensor;
The fuel cell according to claim 1, comprising: A cell stack group in which a plurality of cell stacks in which fuel gas is formed and a hydrocarbon-based gas in which a gas capable of steam reforming is 10 vol% or less is led as a fuel;
The cell stack group is a plurality,
A fuel cell in which a heat transfer tube through which cooling water or water vapor is guided is provided between the cell stack groups.   The fuel cell according to any one of claims 1 to 3, further comprising a water vapor supply pipe that is connected to the heat transfer pipe and guides water vapor to the hydrocarbon-based gas. A boiler connected to the heat transfer tube;
A cooling water supply path for supplying the cooling water to the heat transfer tubes;
A steam supply path for supplying steam generated by the boiler to the heat transfer tube;
With
The fuel cell according to any one of claims 1 to 4, wherein the cooling water supply path and the steam supply path are switchable. Cooling water flow rate control means for controlling the flow rate of cooling water flowing through the cooling water supply path;
Steam flow control means for controlling the flow rate of steam flowing through the steam supply path;
The fuel cell according to claim 5, comprising: A cell stack group in which a plurality of cell stacks in which fuel gas is formed and a hydrocarbon-based gas in which a gas capable of steam reforming is 10 vol% or less is led as a fuel;
A heat insulating wall that houses the cell stack group and forms a power generation chamber;
Water supply means for supplying water or water vapor between each of the cell stacks and the heat insulation wall disposed in the power generation chamber;
A fuel cell comprising:   The fuel cell according to claim 7, wherein the water supply means is a water spray pipe disposed between each cell stack and the heat insulating wall. A cell stack group in which a plurality of cell stacks in which fuel gas is formed and a hydrocarbon-based gas in which a gas capable of steam reforming is 10 vol% or less is led as a fuel;
The cell stack group is a plurality,
A fuel cell in which water supply means for supplying water or water vapor is provided between the cell stack groups. The oxidizing gas supply pipe for supplying an oxidizing gas between each cell stack and the heat insulating wall,
The fuel cell according to claim 7, wherein the water supply unit is a humidifying spray that humidifies the oxidizing gas flowing in the oxidizing gas supply pipe. A gasification furnace for gasifying carbon-containing solid fuel;
The fuel cell according to any one of claims 1 to 7, wherein gasified gas gasified in the gasification furnace is guided,
A gas turbine that generates rotational power using exhaust fuel gas and exhaust oxidant gas exhausted from the fuel cell;
A gas turbine generator that is driven by the rotational power of the gas turbine to generate electricity;
An exhaust gas boiler that generates steam from the exhaust gas discharged from the gas turbine;
A steam turbine that generates rotational power by the steam generated in the exhaust gas boiler;
A steam turbine generator that is driven by the rotational power of the steam turbine to generate electricity;
A combined power generation system.

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