Composite plant and method for manufacturing the same

Abstract

To inhibit damage of a gasification furnace.SOLUTION: A combined plant 1 includes: a gasification furnace 101 which gasifies a solid fuel to generate a product gas; a boiler 30 which causes the solid fuel to burn to generate steam; a char separation device 15 which separates the product gas discharged from the gasification furnace 101 from char contained in the product gas; a char return line 46 which supplies the char separated by the char separation device 15 to the gasification furnace 101: a char supply line 47 which supplies the char separated by the char separation device 15 to the boiler 30; a flow rate adjustment valve 47a which adjusts an amount of the char supplied to the boiler 30 through the char supply line 47; and a control device 96 which controls the flow rate adjustment valve 47a so that an amount of the char which exceeds a predetermined threshold value is supplied to the boiler 30 when an amount of the char supplied to the gasification furnace 101 exceeds the predetermined threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to composite plants and methods for manufacturing composite plants. [Background technology]

[0002] Due to the shift to low-carbon and decarbonized energy, it is expected that low-efficiency coal-fired power plants will be phased out one after another. However, building new power plants is costly and time-consuming. For this reason, it is being considered to improve the energy efficiency of existing coal-fired power plants and continue using them.

[0003] A known type of coal-fired power plant is a power plant that generates electricity by burning finely pulverized coal (pulverized coal) (hereinafter referred to as a "pulverized coal-fired power plant"). Compared to other power plants, pulverized coal-fired power plants emit more carbon dioxide during power generation, and therefore there is a particular demand for improved energy efficiency. One method considered for improving the energy efficiency of a coal-fired power plant is to install a pulverized coal-fired power plant alongside a highly energy-efficient integrated coal gasification combined cycle (IGCC) facility (see, for example, Patent Document 1).

[0004] In an integrated coal gasification combined cycle power plant, coal is gasified in a gasifier, and the gasified gas is used to generate electricity in a gas turbine. After that, heat is recovered from the exhaust gas in a heat recovery steam generator (HRSG) to generate steam, which is then used to generate electricity in a steam turbine. This makes it more efficient than a pulverized coal-fired plant. Therefore, by combining an integrated coal gasification combined cycle power plant with a pulverized coal-fired power plant, the energy efficiency of the entire power plant can be improved.

[0005] Patent Document 1 describes a system in which a coal gasification device is added to an existing coal-fired boiler, and the carbonized gas and char generated in the coal gasification device are collected in a char collector and then separated, with part of the carbonized gas being used as fuel for a gas turbine, and the remaining carbonized gas and char being used as fuel for combustion in the existing coal-fired boiler. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-65804 Summary of the Invention [Problem to be solved by the invention]

[0007] In the gasification furnace of an integrated gasification combined cycle power plant, char (unburned fuel) is generated when solid fuel is gasified. The amount of char generated in the gasification furnace is easily affected by the properties of the solid fuel, and fluctuates depending on the type and properties of the solid fuel. The char generated in the gasification furnace is recovered upstream of the gas turbine and resupplied to the gasification furnace for re-burning, but if the amount of char generated is unstable, the amount of char resupplied to the gasification furnace will also become unstable, which could make it difficult to continue stable operation of the gasification furnace.

[0008] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a composite plant capable of stably operating a gasification furnace, and a method for manufacturing the composite plant. [Means for solving the problem]

[0009] In order to solve the above problems, the composite plant and the method for manufacturing the composite plant of the present disclosure employ the following measures. A composite plant according to one embodiment of the present disclosure includes a gasification furnace that generates a generated gas by gasifying a carbon-containing solid fuel, a boiler that burns the carbon-containing solid fuel to generate steam, a separation unit that separates the generated gas discharged from the gasification furnace from the char contained in the generated gas, a char return line that supplies the char separated in the separation unit to the gasification furnace, a char supply line that supplies the char separated in the separation unit to the boiler, an adjustment unit that adjusts the amount of char supplied to the boiler via the char supply line, and a control unit that, when the amount of char supplied to the gasification furnace exceeds a predetermined threshold, controls the adjustment unit so that an amount of char exceeding the predetermined threshold is supplied to the boiler.

[0010] Furthermore, a manufacturing method for a composite plant according to one aspect of the present disclosure is a manufacturing method for a composite plant including a gasification furnace that generates a generated gas by gasifying a carbon-containing solid fuel and a boiler that burns the carbon-containing solid fuel to generate steam, and includes a gasification furnace installation process for installing the gasification furnace; a separation unit installation process for installing a separation unit in the gasification furnace that separates the generated gas discharged from the gasification furnace from the char contained in the generated gas; a char return line installation process for installing a char return line that supplies the char separated in the separation unit to the gasification furnace; a char supply line installation process for installing a char supply line that supplies the char separated in the separation unit to the boiler so as to connect the existing boiler to the separation unit; and a fuel supply unit installation process for installing a fuel supply unit that supplies the carbon-containing solid fuel to both the gasification furnace and the boiler. [Effects of the Invention]

[0011] According to the present disclosure, the gasification furnace can be operated stably. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram illustrating a composite plant according to an embodiment of the present disclosure. [Figure 2]10 is a timing chart showing control when a gas turbine is stopped in a combined plant according to an embodiment of the present disclosure. [Figure 3] 1 is a graph showing a relationship between a plant load and a mill load in a composite plant according to an embodiment of the present disclosure. [Figure 4] FIG. 10 is a schematic configuration diagram showing a composite plant according to a modified example of the embodiment of the present disclosure. [Figure 5] FIG. 10 is a configuration diagram showing a main part of a composite plant according to a modified example of the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a composite plant and a method for manufacturing a composite plant according to the present disclosure will be described below with reference to the drawings. Fig. 1 is a schematic configuration diagram of a power plant according to an embodiment of the present disclosure. In the following explanation, "upper" refers to the vertically upward direction, and "upper" in terms such as upper part and upper surface refers to the vertically upward part. Similarly, "lower" refers to the vertically downward part, and the vertical direction is not precise and may include errors.

[0014] As shown in FIG. 1, the composite plant 1 of this embodiment includes a gasification combined cycle power generation facility 10, a boiler 30, and a fuel supply facility 80 that supplies solid fuel (e.g., coal or biomass fuel) to both the gasification combined cycle power generation facility 10 and the boiler 30.

[0015] [Gasification combined cycle power generation facility] First, the integrated gasification combined cycle power generation facility 10 will be described. The integrated gasification combined cycle power generation facility 10 to which the gasifier 101 according to this embodiment is applied uses pressurized air as the main oxidizer, and employs a pressurized air combustion system in which the gasifier 101 produces combustible gas (produced gas) from fuel. The integrated gasification combined cycle power generation facility 10 refines the produced gas produced in the gasifier 101 in a gas refinement system 16 to produce fuel gas, which is then supplied to a gas turbine 17 and used in a gas turbine generator 21 to generate electricity. That is, the integrated gasification combined cycle power generation facility 10 according to this embodiment is an air combustion (air-blown) power generation facility. Note that, although the integrated gasification combined cycle power generation facility 10 according to this embodiment will be described as an air combustion system, it may also be an oxygen combustion (oxygen-blown) system that uses oxygen as the main oxidizer. The fuel supplied to the gasifier 101 may be, for example, a carbon-containing solid fuel such as biomass fuel or coal.

[0016] 1, the integrated gasification combined cycle power generation facility 10 includes a gasifier 101, a char separation device 15, a gas purification facility 16, a gas turbine 17, a gas turbine generator 21, a steam turbine 18, a steam turbine generator 19, and a heat recovery boiler 20. The fuel supply facility 80 and the steam turbine 18 are shared with a boiler 30, which will be described later.

[0017] The gasifier 101 is supplied with pulverized fuel from a fuel supply facility 80. The gasifier 101 also receives char (unreacted portion of solid fuel) separated and recovered by a char separator 15 for the purpose of reusing it as energy.

[0018] The gasifier 101 is configured, for example, as a two-stage entrained flow type, and gasifies pulverized fuel and char supplied therein by partial combustion with an oxidizing agent (air, oxygen) to produce a produced gas. A first produced gas line 49 that supplies the produced gas to the char separation device 15 is connected to the gasifier 101, and the produced gas containing char can be discharged. The wall of the gasifier 101 has a water-cooled peripheral wall pipe through which water flows.

[0019] The char separator 15 separates the product gas generated in the gasifier 101 from the char contained in the product gas. The char separator 15 has, for example, one or more cyclones, and separates the product gas from the char by centrifugal separation. The product gas from which the char has been separated is sent to the gas purification equipment 16 via the second product gas line 53. The char separated from the product gas is temporarily stored, for example, in a hopper (not shown). The char stored in the hopper is guided to the gasifier 101 via the char return line 46. That is, the char return line 46 supplies the char separated in the char separator 15 to the gasifier 101.

[0020] The gas purification equipment 16 purifies the produced gas from which char has been separated by the char separator 15 by removing impurities such as sulfur compounds and nitrogen compounds. The gas purification equipment 16 then purifies the produced gas to produce fuel gas, which is then supplied to a gas turbine 17.

[0021] The gas turbine 17 is supplied with fuel gas obtained by refining the produced gas from the gas purification equipment 16 via a fuel gas supply line 66. The gas turbine 17 rotates the turbine and a rotating shaft fixed to the turbine with combustion gas obtained by combusting the supplied fuel gas, thereby driving and rotating a gas turbine generator 21 connected to the rotating shaft.

[0022] The combustion gas (exhaust gas) discharged from the gas turbine 17 is led to the heat recovery boiler 20 via an exhaust gas line 70. The heat recovery boiler 20 generates steam by exchanging heat between feedwater and the exhaust gas. Nitrogen oxides are removed from the exhaust gas discharged from the heat recovery boiler 20 in a denitrification system 22, and the exhaust gas is discharged outside the system from a chimney 39.

[0023] Steam is supplied to the steam turbine 18 from the gasifier 101, the heat recovery steam generator 20, and the boiler 30 via a first steam line 23, a second steam line 24, and a third steam line 25. The steam turbine 18 rotates the turbine and a rotating shaft fixed to the turbine with the supplied steam, thereby driving and rotating a steam turbine generator 19 connected to the rotating shaft. The steam discharged from the steam turbine 18 is led to the condenser 73. In the condenser 73, the steam is condensed into water. The water condensed in the condenser 73 is led as feedwater to the gasifier 101, the heat recovery steam generator 20, and the boiler 30 via the first feedwater line 26, the second feedwater line 27, and the third feedwater line 28.

[0024] [Boiler] Next, the boiler 30 will be described. The boiler 30 according to this embodiment is a boiler that can generate superheated steam by burning pulverized fuel made by pulverizing solid fuel using a burner 35 and exchanging the heat generated by this combustion with feedwater or steam. Biomass fuel, coal, etc. are used as the solid fuel.

[0025] The boiler 30 has a furnace 31, multiple burners 35, and a combustion gas passage 32. The furnace 31 has a hollow rectangular cylindrical shape and is installed vertically. Combustion gas is generated by combusting pulverized fuel inside the furnace 31.

[0026] A plurality of burners 35 are installed in the lower region of the furnace 31. The burners 35 are arranged at equal intervals along the circumferential direction of the furnace 31 (for example, four burners installed at each corner of the rectangular furnace 31) as one set, and are arranged in multiple rows along the vertical direction. Note that, for convenience of illustration, only one burner 35 of one set is shown in FIG. 1. The shape of the furnace, the number of rows of burners 35, the number of burners 35 in one row, the arrangement of the burners 35, and the like are not limited to this embodiment.

[0027] The burners 35 are each connected to a mill 31 via a pulverized fuel line 86 .

[0028] The combustion gas passage 32 is connected to the vertical upper part of the furnace 31. The combustion gas passage 32 is provided with a plurality of heat exchangers (e.g., superheaters, reheaters, economizers, etc.) (not shown) for recovering heat from the combustion gas, and heat is exchanged between the combustion gas generated in the furnace 31 and the feedwater or steam flowing inside each heat exchanger.

[0029] A flue 33 is connected to the downstream side of the combustion gas passage 32, and discharges the combustion gas for which heat has been recovered in each heat exchanger. A denitration device 37 is provided in the flue 33. The denitration device 37 supplies a reducing agent, such as ammonia or urea water, which has the effect of reducing nitrogen oxides, to the combustion gas flowing through the flue 33, and promotes the reaction between the nitrogen oxides (NOx) in the combustion gas to which the reducing agent has been supplied and the reducing agent by the catalytic action of a denitration catalyst provided in the denitration device 37, thereby removing and reducing the nitrogen oxides in the combustion gas. Furthermore, a desulfurization facility 38 for removing sulfur oxides from the combustion gas is provided downstream of the denitration facility 37 in the flue 33. The downstream end of the flue 33 is connected to a chimney 39, and the combustion gas treated by the environmental device is discharged outside the system as exhaust gas.

[0030] Next, the operation of the boiler 30 according to this embodiment will be described. In the boiler 30, when the multiple mills 82 are driven, the pulverized and classified pulverized fuel is stored in a separator 83 and a pulverized fuel hopper (pulverized fuel storage section) 84. The pulverized fuel stored in the pulverized fuel hopper 84 is transported by primary air via a first pulverized fuel supply line 87 and supplied to the burner 35. Secondary air (combustion air) heated by an air preheater (not shown) is also supplied to the burner 35. The burner 35 injects the primary air (transport air) and pulverized fuel into the furnace 31, and also injects secondary air into the furnace 31 from the surrounding area. The pulverized fuel injected into the furnace 31 ignites and reacts with the primary and secondary air to form a flame. A flame is formed in the lower region of the furnace 31, and high-temperature combustion gas rises within the furnace 31 and flows into the combustion gas passage 32.

[0031] The combustion gas that flows into the combustion gas passage 32 exchanges heat with water or steam in a heat exchanger arranged inside the combustion gas passage 32, and is then discharged into a flue 33, where nitrogen oxides are removed in a denitration equipment 37 and sulfur oxides are removed in a desulfurization equipment 38, and the combustion gas is then discharged outside the system from a chimney 39.

[0032] [Fuel supply equipment] Next, the fuel supply equipment 80 will be described. The fuel supply equipment 80 according to this embodiment supplies solid fuel to both the integrated gasification combined cycle power generation plant 10 and the boiler 30. In other words, the fuel supply equipment 80 is shared by the integrated gasification combined cycle power generation plant 10 and the boiler 30.

[0033] The fuel supply equipment 80 includes a bunker 81 for storing solid fuel, a plurality of mills 82 for pulverizing the solid fuel guided from the bunker 81, a separator 83 to which the solid fuel pulverized by the mills 82 (pulverized solid fuel, which is pulverized fuel) is guided together with a carrier gas, a pulverized fuel hopper 84 for temporarily storing the pulverized fuel separated from the carrier gas by the separator 83, and a pressure hopper 85 for pressurizing the pulverized fuel guided from the pulverized fuel hopper 84.

[0034] The mill 82 is, for example, a vertical roller mill having a grinding table (not shown) supported therein so that it can be driven and rotated, and a plurality of grinding rollers (not shown) supported above the grinding table so that they can rotate in conjunction with the rotation of the grinding table. The solid fuel ground by the cooperation of the grinding rollers and the grinding table is transported to a classifier (not shown) provided in the mill 82 by a carrier gas supplied into the mill 82. The classifier classifies the solid fuel into pulverized fuel having a particle size equal to or smaller than that suitable for combustion in the burner 35 provided in the gasifier 101 or the boiler 30, and coarse pulverized fuel having a particle size larger than that. The pulverized fuel passes through the classifier and is supplied together with the carrier gas to the separator 83 via a pulverized fuel line 86. The coarse pulverized fuel that does not pass through the classifier falls onto the grinding table inside the mill 82 by its own weight and is re-ground.

[0035] The separator 83 has, for example, one or more cyclones and separates the carrier gas from the pulverized fuel by centrifugal separation. An exhaust port is formed at the top of the separator 83 to discharge the separated carrier gas. The separator 83 has a lower end connected directly or indirectly to the upper end of a pulverized fuel hopper 84. The pulverized fuel hopper 84 has a lower end connected directly or indirectly to the upper end of a pressure hopper 85. The pulverized fuel hopper 84 is connected to a plurality of (five in this embodiment, for example) first pulverized fuel supply lines 87. The pressure hopper 85 is connected to an end of a second pulverized fuel supply line 88.

[0036] In this embodiment, the pulverized fuel pulverized by the mill 82 is temporarily stored in a pulverized fuel hopper 84. The pulverized fuel stored in the pulverized fuel hopper 84 can be supplied to both the integrated gasification combined cycle power generation facility 10 and the boiler 30 via a first pulverized fuel supply line 87 or a second pulverized fuel supply line 88, and a measuring and conveying device (not shown) is installed to feed and convey the amount of fuel required for each facility. The measuring and conveying device is controlled by a control device 96, which will be described later.

[0037] [Control device] Next, the control device 96 provided in the composite plant 1 according to this embodiment will be described. The control device 96 is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and computer-readable storage media. A series of processes for realizing various functions is stored in, for example, a storage medium in the form of a program. The CPU reads this program into RAM and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed 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. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0038] The control device 96 controls various valves (for example, the flow rate control valve 47a), a measuring and conveying device, etc. provided in the complex plant 1. The control device 96 also receives the amount of char and the amount of produced gas measured by a char measuring means and a produced gas measuring means, which will be described later.

[0039] For example, when the amount of char supplied to the gasifier 101 exceeds a predetermined threshold, the control device 96 controls the flow rate adjustment valve 47a so that the amount of char exceeding the predetermined threshold is supplied to the boiler 30. By adjusting the amount of char supplied to the gasifier 101 so that it does not exceed the predetermined threshold, the gasifier 101 can continue to operate stably.

[0040] The control device 96 also receives the amount of char fed to the boiler 30 via the char supply line 47 from the char measurement means, and derives the amount of heat input from the fed char by multiplying it by the calorific value per unit weight of the char. The control device 96 then controls the measuring and conveying device to reduce the amount of pulverized fuel fed to the boiler 30 by an amount equivalent to the derived amount of heat input from the char. In this way, the amount of heat input to the boiler 30 can be kept constant, thereby stabilizing operation. Furthermore, there are cases where it is necessary to rapidly change the amount of pulverized fuel fed to the boiler 30, for example, when the amount of char generated suddenly changes during operation of the integrated gasification combined cycle power generation facility 10. In this embodiment, the pulverized fuel fed to the boiler 30 is stored in a pulverized fuel hopper 84. Therefore, the amount of pulverized fuel fed to the boiler 30 can be adjusted without being affected by a delay in the response of the mill 82 to a change in the fuel supply amount.

[0041] The control device 96 also receives from the produced gas measurement means the amount of produced gas input to the boiler 30 via the produced gas supply line 54, and derives the amount of heat input by the input produced gas by multiplying the amount by the calorific value per unit weight of the produced gas. The control device 96 then controls the flow rate adjustment valve 47a to reduce the amount of pulverized fuel input to the boiler 30 by an amount equivalent to the amount of heat input by the derived produced gas. In this way, the amount of heat input to the boiler 30 can be kept constant, thereby stabilizing operation. Furthermore, for example, when the gas turbine 17 trips during operation of the integrated gasification combined cycle power generation facility 10, there may be cases where it is necessary to rapidly change the amount of pulverized fuel fed to the boiler 30. In this embodiment, the pulverized fuel fed to the boiler 30 is stored in the pulverized fuel hopper 84. Therefore, the amount of pulverized fuel fed to the boiler 30 can be adjusted without being affected by a delay in the response of the mill 82 to a change in the fuel supply amount.

[0042] Next, the processing of the control device 96 when the gas turbine 17 is stopped in an emergency will be described with reference to Fig. 2. Fig. 2(a) shows the change in the amount of generated gas and char fed to the boiler 30. Fig. 2(b) shows the change in the amount of pulverized fuel fed to the boiler 30. Fig. 2(c) shows the change in the amount of solid fuel fed to the mill 82. Fig. 2(d) shows the change in the amount of pulverized fuel discharged from the mill 82. Fig. 2(e) shows the change in the amount of pulverized fuel held in the pulverized fuel hopper 84.

[0043] 2(a), at the timing (t) when the gas turbine 17 makes an emergency stop, the control device 96 switches the supply destination of the produced gas and char to the boiler 30. Therefore, the input amounts of the produced gas and char to the boiler 30 increase at the timing t. 2(b), the control device 96 reduces the amount of pulverized fuel input to the boiler 30 at timing t. This is to keep the amount of heat input to the boiler 30 constant. In other words, the control device 96 reduces the amount of pulverized fuel input to the boiler 30 by an amount equivalent to the amount of heat input by the generated gas and char input to the boiler 30. As shown in Fig. 2(c), the control device 96 reduces the amount of solid fuel supplied to the mill 82 in response to a decrease in the amount of pulverized fuel fed into the boiler 30 at time t. Meanwhile, as shown in Fig. 2(d), the amount of pulverized fuel discharged from the mill 82 gradually decreases with a certain time delay. Therefore, as shown in Fig. 2(e), the amount of pulverized fuel held in the pulverized fuel hopper 84 gradually increases and then gradually decreases. In this way, the pulverized fuel hopper 84 functions as a buffer to absorb fluctuations in the pulverized fuel due to a delay in the load response of the mill 82. The amount of pulverized fuel held in the pulverized fuel hopper 84 may be controlled so as to be balanced at a specified level. For example, the amount of solid fuel supplied to the mill 82 may be reduced when the amount of pulverized fuel held in the pulverized fuel hopper 84 exceeds a specified level, and the amount of solid fuel supplied to the mill 82 may be increased when the level in the pulverized fuel hopper 84 falls below a specified value. The object of control is not limited to the level, and the amount of pulverized fuel held in the pulverized fuel hopper 84 may be calculated and controlled by integrating the amount put into and discharged from the pulverized fuel hopper 84, or may be controlled by the weight of the pulverized fuel hopper 84. The amount of pulverized fuel held in the pulverized fuel hopper 84 may also be controlled by the rate of increase / decrease, the acceleration of increase / decrease, etc.

[0044] [Flow of solid fuel and produced gas, etc.] Next, the flow of the solid fuel, the produced gas, etc. in the composite plant 1 of this embodiment will be described. As shown in FIG. 1, solid fuel is stored in storage facility 91 by solid fuel receiving facility 90. The solid fuel stored in storage facility 91 is transported by a conveyor or the like and supplied to bunker 81. A predetermined amount of solid fuel temporarily stored in bunker 81 is cut out and supplied to each mill 82. The solid fuel supplied to each mill 82 is pulverized by a pulverizing roller and pulverizing table (not shown) to become pulverized fuel. The pulverized fuel pulverized in each mill 82 is guided to separator 83 via pulverized fuel line 86 by a carrier gas supplied into the mill 82.

[0045] The separator 83 separates the pulverized fuel from the carrier gas. The separated carrier gas is exhausted from the separator 83 to the atmosphere. Meanwhile, the separated pulverized fuel is led to a pulverized fuel hopper 84. The pulverized fuel hopper 84 temporarily stores the pulverized fuel. The pulverized fuel produced by each mill 82 is led to the pulverized fuel hopper 84. That is, in this embodiment, there is one pulverized fuel hopper 84.

[0046] The pulverized fuel stored in the pulverized fuel hopper 84 is dispensed in a predetermined amount by a measuring and conveying device and supplied to the boiler 30 and the gasifier 101. The presence or absence of pulverized fuel supply to each facility and the amount of supply are adjusted by a control device 96. The pulverized fuel in the pulverized fuel hopper 84 that is led to the boiler 30 is led to each burner 35 via a first pulverized fuel supply line 87. A plurality of first pulverized fuel supply lines 87 (five in this embodiment, for example) are provided. The first pulverized fuel supply lines 87 connect the pulverized fuel hopper 84 and each burner 35 provided in the boiler 30. Furthermore, the pulverized fuel in the pulverized fuel hopper 84 that is led to the gasification combined cycle power generation facility 10 is led to a pressurized hopper 85. The pulverized fuel led to the pressurized hopper 85 is pressurized together with a conveying inert gas such as nitrogen gas, and is supplied to the gasifier 101 via a second pulverized fuel supply line 88.

[0047] Next, the flow of the pulverized fuel and the like in the boiler 30 will be described. As described above, pulverized fuel is supplied to the burner 35 together with carrier air (primary air) from the pulverized fuel hopper 84 via the first pulverized fuel supply line 87. In addition, combustion air (secondary air) heated by an air preheater (not shown) is supplied to the burner 35. The burner 35 injects the pulverized fuel and primary air into the furnace 31, and also injects secondary air into the furnace 31 from the surrounding area. The pulverized fuel injected into the furnace 31 ignites and reacts with the primary air and secondary air to form a flame. A flame is formed in the lower region of the furnace 31, and high-temperature combustion gas rises within the furnace 31 and flows into the combustion gas passage 32. The combustion gas that flows into the combustion gas passage 32 exchanges heat with water or steam in a heat exchanger arranged inside the combustion gas passage 32, and is then discharged into a flue 33, where nitrogen oxides are removed in a denitration equipment 37 and sulfur oxides are removed in a desulfurization equipment 38, and the combustion gas is then discharged outside the system from a chimney 39.

[0048] Next, the flow of pulverized fuel and the like in the integrated gasification combined cycle power generation facility 10 will be described. As described above, the gasifier 101 is supplied with pulverized fuel together with carrier gas from the pulverized fuel hopper 84 via the pressure hopper 85 and the second pulverized fuel supply line 88. In addition, the gasifier 101 is supplied with char separated in the char separator 15 via the char return line 46. In addition, combustion air is supplied to the gasifier 101. A char supply line 47 branches off from the char return line 46 at a midpoint. The char supply line 47 is connected to a char burner 34 provided in the boiler 30. Char can be supplied to the boiler 30 via the char supply line 47 to be used as fuel for the boiler 30. The char supply line 47 is provided with a flow control valve 47a that adjusts the amount of char flowing therethrough. The char supply line 47 may also be provided with a char measuring means (not shown) that measures the amount of char fed into the boiler 30.

[0049] In the gasifier 101, the supplied pulverized fuel and char are partially combusted with combustion air, and the pulverized fuel and char are gasified to generate a produced gas. The produced gas is discharged from the gasifier 101 through a first produced gas line 49 and sent to the char separator 15.

[0050] In the char separator 15, the produced gas is separated from the char contained in the produced gas. The produced gas from which the char has been separated is sent to the gas purification facility 16 through a second produced gas line 53. Meanwhile, the char separated from the produced gas is returned to the gasifier 101 through a char return line 46 and recycled. A produced gas supply line 54 branches off from a midpoint of the second produced gas line 53. The produced gas supply line 54 is connected to a produced gas burner 36 provided in the boiler 30. The produced gas supply line 54 supplies the produced gas to the boiler 30, where it can be used as fuel for the boiler 30. The produced gas supply line 54 may also be provided with a produced gas measuring means (not shown) that measures the amount of produced gas input to the boiler 30.

[0051] The gas purification equipment 16 purifies the generated gas by removing impurities such as sulfur compounds and nitrogen compounds from the generated gas, thereby producing fuel gas. The fuel gas produced in the gas purification equipment 16 is led to the gas turbine 17 via a fuel gas supply line 66. The gas turbine 17 generates combustion gas by combusting the fuel gas supplied from the gas purification equipment 16. This combustion gas drives the turbine to rotate, which in turn drives the gas turbine generator 21 to rotate via its rotating shaft. In this way, the gas turbine 17 generates electricity.

[0052] The combustion gas (exhaust gas) discharged from the gas turbine 17 is introduced to a heat recovery boiler 20. The heat recovery boiler 20 generates steam by exchanging heat between the exhaust gas and feedwater.

[0053] The exhaust gas discharged from the heat recovery boiler 20 is passed through a denitrification facility 22 where nitrogen oxides are removed, and the gas is then released from a chimney 39 to the outside of the system.

[0054] [Water and steam flow] Next, the flow of water and steam in the composite plant 1 of this embodiment will be described. A heat exchanger disposed inside the combustion gas passage 32 of the boiler 30 exchanges heat between the combustion gas generated in the furnace 31, which is in contact with the outer circumferential surface of the heat transfer tube, and the feedwater flowing inside the heat transfer tube, thereby evaporating the feedwater and generating steam. The steam generated in the boiler 30 is supplied to the steam turbine 18 via a first steam line 23. The first steam line 23 connects the boiler 30 and the steam turbine 18.

[0055] Furthermore, a heat exchanger (water-cooled peripheral wall tube, product gas cooler, etc.) disposed inside the gasifier 101 exchanges heat between the product gas in contact with the outer peripheral surface of the heat transfer tube and the feed water flowing inside the heat transfer tube, thereby evaporating the feed water and generating steam. The steam generated in the gasifier 101 is supplied to the steam turbine 18 via the second steam line 24 and the first steam line 23. The second steam line 24 connects the gasifier 101 and a midpoint of the first steam line 23.

[0056] Furthermore, a heat exchanger disposed inside the heat recovery boiler 20 exchanges heat between the combustion gas discharged from the gas turbine 17, which is in contact with the outer peripheral surfaces of the heat transfer tubes, and the feedwater flowing inside the heat transfer tubes, thereby evaporating the feedwater and generating steam. The steam generated in the heat recovery boiler 20 is supplied to the steam turbine 18 via a third steam line 25, a second steam line 24, and a first steam line 23. The third steam line 25 connects the heat recovery boiler 20 and a midpoint of the second steam line 24.

[0057] The steam turbine 18 rotates the turbine using steam, which in turn rotates the steam turbine generator 19 via a rotary shaft. In this way, electricity is generated by the steam turbine 18. The steam discharged from the steam turbine 18 is condensed in a condenser 73 and becomes feed water.

[0058] The feedwater discharged from the condenser 73 is supplied to the boiler 30 via the first feedwater line 26, where it is heated in a heat exchanger and turned into steam. The first feedwater line 26 connects the condenser 73 and the boiler 30. In this way, the steam and feedwater circulate between the steam turbine 18 and the boiler 30. Furthermore, the feedwater discharged from the condenser 73 is supplied to the gasifier 101 via the first feedwater line 26 and the second feedwater line 27, and is heated in the heat exchanger to become steam. The second feedwater line 27 connects a midpoint of the first feedwater line 26 to the gasifier 101. In this way, the steam and feedwater circulate between the steam turbine 18 and the gasifier 101. Furthermore, the feedwater discharged from the condenser 73 is supplied to the heat recovery steam generator 20 via the first feedwater line 26, the second feedwater line 27, and the third feedwater line 28, and is heated in a heat exchanger to become steam. The third feedwater line 28 connects a midpoint of the second feedwater line 27 to the heat recovery steam generator 20. In this way, the steam and feedwater circulate between the steam turbine 18 and the heat recovery steam generator 20.

[0059] [Manufacturing method] Next, a method for manufacturing the composite plant 1 will be described. In this embodiment, the integrated plant 1 is manufactured by adding an integrated gasification combined cycle power generation facility 10 to an existing boiler 30. The existing boiler 30 has a fuel supply facility 80. Furthermore, the existing boiler 30 is often designed to have ample equipment capacity, for example, by having a spare mill 82. Therefore, as in this embodiment, by sharing the fuel supply facility 80 between the integrated gasification combined cycle power generation facility 10 and the boiler 30, the existing fuel supply facility 80 of the existing boiler 30 can be reused to manufacture the integrated plant 1. This reduces the manufacturing cost of the integrated plant 1. Furthermore, the installation area of ​​the integrated plant 1 can be reduced.

[0060] When manufacturing the composite plant 1, an integrated gasification combined cycle power generation facility 10 including a gasifier 101 is installed on the same site as the existing boiler 30 (gasifier installation step). A char separation device 15 is also installed for the gasifier 101 (separation unit installation step). A fuel supply facility 80 that supplies pulverized fuel to the gasifier 101 and the boiler 30 is also installed (fuel supply unit installation step). In this case, it is possible to reuse equipment such as the mill 82 that is equipped in the existing boiler 30, and if some of the equipment (separator 83, pulverized fuel hopper 84, pressure hopper 85, etc.) of the fuel supply facility 80 that the existing boiler 30 has is missing, it is only necessary to appropriately add only the missing equipment. After the integrated gasification combined cycle power generation facility 10 and fuel supply facility 80 are installed, a char return line 46 is then installed to supply the char separated in the char separation device 15 to the gasification furnace 101 (char return line installation process). In addition, a char supply line 47 is installed to connect the existing boiler 30 and the char separation device 15 (char supply line installation process). In addition, various other pipes and the like are connected. In this way, the composite plant 1 is manufactured.

[0061] According to this embodiment, the following advantageous effects are achieved. In this embodiment, the boiler 30 is combined with the highly energy-efficient integrated gasification combined cycle power generation facility 10, thereby improving the energy efficiency of the entire integrated plant 1. Furthermore, when the same amount of fuel is input as before the boiler 30 and integrated gasification combined cycle power generation facility 10 were combined, the output of the integrated plant 1 can be easily improved. This is because the gas turbine 17 is added to the existing steam turbine 18, and the output of the integrated plant 1 can be easily improved by adding the output from the steam turbine 18 and the output from the gas turbine 17. In this case, power transmission equipment and substation equipment for transmitting power from the gas turbine 17 may be added.

[0062] Furthermore, in this embodiment, a control device 96 is provided that, when the amount of char supplied to the gasifier 101 exceeds a predetermined threshold, controls the flow rate adjustment valve 47a so that the amount of char exceeding the predetermined threshold is supplied to the boiler 30. This makes it possible to stabilize the amount of char returned to the gasifier 101. Therefore, combustion in the gasifier 101 can be stabilized, enabling the gasifier 101 to be operated stably and improving the reliability of the gasifier 101. The predetermined threshold is an upper limit amount of char that allows the gasifier 101 to be operated stably, and is determined, for example, by the allowable heat load inside the gasifier 101, etc.

[0063] The effect of stabilizing combustion in the gasifier 101 will be described in detail. In the integrated gasification combined cycle power generation facility 10, the gas generated in the gasifier 101 contains char. This char is unburned matter, i.e., solid matter remaining after pulverized fuel has released volatile matter, and contains a large amount of fixed carbon. Because solid fuel cannot be fed into the gas turbine 17, the char is separated from the generated gas in the char separator 15 downstream of the gasifier 101. The separated char is returned to the gasifier 101 and reburned. However, the amount of char generated is significantly affected by the properties of the fuel, making it difficult to control. When the entire amount of char is fed into the gasifier 101, if the amount of char generated in the gasifier 101 becomes unstable, the amount of char supplied may become excessive, potentially destabilizing combustion in the gasifier 101. On the other hand, in this embodiment, all or part of the generated char is fed as fuel to the boiler 30, thereby stabilizing the amount of char returned to the gasifier 101. Because char is also a fuel, burning it in the gasifier 101 improves the energy efficiency of the entire integrated plant 1, but as mentioned above, fluctuations in the amount of char supplied to the gasifier 101 may cause combustion in the gasifier 101 to become unstable. Therefore, it is preferable to feed char up to the allowable upper limit amount into the gasifier 101, and feed any large fluctuations exceeding this amount into the boiler 30.

[0064] Furthermore, in this embodiment, the pulverized fuel pulverized by the mill 82 is supplied to both the gasifier 101 and the boiler 30. That is, the fuel supply equipment 80 is shared by the gasifier 101 and the boiler 30. This reduces the number of devices provided in the complex plant 1 and simplifies the equipment compared to when the fuel supply equipment 80 that pulverizes the pulverized fuel to be supplied to the gasifier 101 and the fuel supply equipment 80 that pulverizes the pulverized fuel to be supplied to the boiler 30 are provided separately. Therefore, the installation area of ​​the complex plant 1 can be reduced. Furthermore, the initial cost of manufacturing the complex plant 1 can be reduced. Furthermore, the number of devices of the fuel supply equipment 80 that require maintenance can be reduced, thereby reducing running costs.

[0065] Furthermore, in a configuration in which the pulverized fuel hopper 84 is not provided, the mill 82 and the boiler 30 are directly connected. In this case, in order to transport and dry the pulverized fuel used in the mill 82, the carrier gas used in the mill 82 is directly input into the boiler 30 together with the pulverized fuel, and is used as primary air when burning the pulverized fuel. Therefore, for example, if the temperature or flow rate of the carrier gas is increased to dry solid fuel containing a large amount of moisture, the amount of primary air supplied to the boiler 30 also increases, which may result in restrictions on the operation of the boiler 30, such as an increase in nitrogen oxides generated in the boiler 30. On the other hand, in this embodiment, pulverized fuel stored in a pulverized fuel hopper 84 is supplied to the boiler 30. That is, a separator 83 and a pulverized fuel hopper 84 are provided between the mill 82 and the boiler 30. The separator 83 separates the pulverized fuel from the carrier gas. The separated pulverized fuel is transported to the burner 35 by primary air of an amount suitable for combustion in the boiler 30. This prevents the mill 82 from being directly connected to the boiler 30, and prevents the carrier gas from the mill 82 from being introduced to the boiler 30. Therefore, the amount and temperature of the carrier gas in the mill 82 can be set according to the properties of the solid fuel. Furthermore, since the amount of carrier gas input to the mill 82 can be increased, the drying performance in the mill 82 can be improved, and safety can be improved by lowering the carrier gas temperature.

[0066] Furthermore, primary air is transported from the pulverized fuel hopper 84 to each burner 35 in an amount and temperature suitable for combustion in the burners 35, thereby minimizing operational constraints on the boiler 30. The gas used as a carrier gas in the mill 82 may also be reused as primary air for transport to the burners 35.

[0067] In addition, in this embodiment, a pulverized fuel hopper 84 is installed between the mill 82 and the burner 35. When the mill 82 and the burner 35 of the boiler 30 are directly connected, the range of change in combustion capacity of each burner 35 and the range of change in load of the boiler 30 are often limited by the operable range of the mill 82. On the other hand, in this embodiment, the pulverized fuel is temporarily stored in the pulverized fuel hopper 84, so the operable range of the mill 82 and the operable range of the burner 35 can be separated. Furthermore, when the pulverized fuel hoppers 84 corresponding to multiple mills 82 are combined into one, the relationship between the number of operating mills 82 and the number of operating burners 35 can also be separated, allowing for more flexible operation of the boiler 30.

[0068] Specifically, as shown in FIG. 3, when the mill 82 and the burner 35 are directly connected (see the dashed line in FIG. 3), when the load of the boiler 30 is varied from the maximum load to the minimum load, the load of the mill 82 corresponding to (directly connected to) the burner 35 reaches its minimum before the load of the burner 35 reaches its minimum, and the load of the burner 35 cannot be reduced any further. For this reason, the load of the boiler 30 has been reduced by stopping the burner 35 and the corresponding mill 82 and reducing the number of operating units. Specifically, as shown in FIG. 3, when the boiler 30 is at its maximum load, five burners 35 (and their corresponding mills 82) are operating. However, in the process of reducing the load of the boiler 30, the load of the five operating mills 82 reaches its minimum lower limit, so the number of operating burners 35 (and their corresponding mills 82) is reduced to four, thereby further reducing the load of the boiler 30. When the load on the four operating mills 82 again reaches its minimum, the number of operating burners 35 (and their corresponding mills 82) is reduced to three, and the load on the boiler 30 is reduced to its minimum. As a result, a waiting time T occurs each time the mill 82 corresponding to a burner 35 is stopped, lengthening the time required to reduce the load on the boiler 30. On the other hand, in this embodiment, the burners 35 and the mills 82 are not directly connected, so the operable range of the mill 82 and the operable range of the burners 35 can be separated, and the load on the burner 35 can be reduced regardless of the load on the mill 82. Therefore, as shown by the dashed arrow in FIG. 3, the speed at which the load is changed can be improved. In addition, the pulverized fuel stored in the pulverized fuel hopper 84 and the space therein function as a buffer. For example, when increasing the load on the boiler 30, the speed at which the load can be changed can be further improved by increasing the amount of fuel supplied to the boiler 30 using the pulverized fuel stored in the pulverized fuel hopper 84 without waiting for the mill 82 to follow the load. In addition, when decreasing the load on the boiler 30, the speed at which the load can be changed can be improved by decreasing the amount of fuel supplied to the boiler 30 within the allowable spatial volume of the pulverized fuel hopper 84 without waiting for the mill 82 to follow the load.

[0069] In addition, in general, the specifications for mills in integrated gasification combined cycle power generation plants are chosen to reduce costs by increasing the size and minimizing the number of mills. This is because integrated gasification combined cycle power generation plants are equipped with pulverized fuel hoppers, so there is no need to install the same number of mills as the number of burner stages. In this case, installing spare mills to ensure redundancy would increase costs. For this reason, spare mills are not often installed in integrated gasification combined cycle power generation plants. Without spare mills, stopping one or more mills for maintenance could result in an insufficient amount of milling, potentially leading to a decrease in the load and availability of the integrated gasification combined cycle power generation plant. In contrast, in this embodiment, the mill 82 installed in the existing boiler 30 is reused. Typically, a boiler is equipped with multiple mills, approximately six in number, including a spare mill. For this reason, the integrated plant 1 of this embodiment is equipped with a spare mill 82 in addition to multiple mills 82. This allows redundancy to be ensured, because even if one mill 82 is undergoing maintenance, the operation of the gasification combined cycle power generation facility 10 and the boiler 30 can be continued by starting up the spare mill 82.

[0070] Furthermore, the addition of the integrated gasification combined cycle power generation facility 10 improves the energy efficiency of the integrated plant 1. Therefore, if the output of the integrated plant 1 is not changed, the amount of fuel consumed by the integrated plant 1 decreases. This also reduces the total amount of solid fuel pulverized by the mill 82. However, the configuration of the existing boiler 30, as described above, links one burner 35 with one mill 82, making it difficult to reduce the number of operating mills 82 due to limitations on the operable load range. In this embodiment, the fuel supply facility 80 is equipped with a pulverized fuel hopper 84, which separates the operable ranges of the mill 82 and the burner 35. This allows the number of operating mills 82 and burners 35 to be freely changed depending on the required fuel amount. This allows the number of operating mills 82 to be kept to a minimum, thereby reducing power consumption and further improving the energy efficiency of the integrated plant 1.

[0071] Furthermore, in this embodiment, a produced gas supply line 54 is provided that supplies a portion of the produced gas generated in the gasifier 101 to the boiler 30. As a result, for example, when excess produced gas is generated in the gasifier 101, the excess produced gas can be supplied to the boiler 30 via the produced gas supply line 54 and combusted in the boiler 30. Because the produced gas can be combusted in the existing boiler 30 in this way, the number of devices to be provided in the integrated plant 1 can be reduced and the equipment can be simplified compared to when a separate device (e.g., a ground flare) is provided to combust the excess produced gas. Therefore, the installation area of ​​the integrated plant 1 can be reduced. Furthermore, the initial cost of the integrated plant 1 can be reduced. Furthermore, by combusting the excess produced gas in the boiler 30, the energy of the excess produced gas can be used to generate electricity. Therefore, the energy efficiency of the integrated plant 1 as a whole can be improved compared to when a device (e.g., a ground flare) is provided solely for combusting the produced gas.

[0072] The present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

[0073] Furthermore, the gasification furnace of the present invention is not limited to power generation applications but can also be used as a gasification furnace for a chemical plant that obtains desired chemical substances, and the boiler of the present invention is not limited to power generation applications but can also be used as a heat source in a factory or as a boiler for generating steam for heating.

[0074] Furthermore, in the case of coal as fuel used in the gasifier and boiler, it is possible to use a variety of coals, such as high-grade coal (anthracite, bituminous coal, subbituminous coal, etc.) and low-grade coal (brown coal, lignite, peat, etc.).In addition to coal, biomass fuels used as renewable organic resources derived from living organisms may also be used, such as thinned wood, waste wood, driftwood, grass, waste, sludge, waste tires, and recycled fuels (pellets and chips) made from these materials.

[0075] Furthermore, in the above embodiment, an example has been described in which the char fed into the boiler 30 is fed into the furnace 31 by a dedicated burner (char burner 34), but the present disclosure is not limited to this. For example, char may be mixed into the pulverized fuel line 86, and the pulverized fuel and char may be mixed and burned. Furthermore, the char obtained from the gasifier 101 is in a fine powder form, but is difficult to combust because volatile matter is removed within the gasifier 101. For this reason, it is preferable to provide the char burner 34 as upstream as possible of the furnace 31 of the boiler 30 (at the lower end in this embodiment) to increase the residence time of the char within the furnace 31. Furthermore, in this embodiment, a produced gas burner 36 to which produced gas is supplied is provided, but since gas fuel burns quickly, the produced gas burner 36 may be installed anywhere.

[0076] Furthermore, for example, in this embodiment, the carrier gas used in the mill 82 is not directly fed into the boiler 30. Therefore, other fluids may be used as the carrier gas instead of air. For example, the exhaust gas from the gas turbine 17 may be used as the carrier gas. In this case, the oxygen concentration in the mill 82 decreases. Therefore, even when transporting highly volatile pulverized fuel such as subbituminous coal, it is possible to suppress the oxidative temperature rise and ignition of the pulverized fuel in the mill 82 and the pulverized fuel line 86.

[0077] Furthermore, for example, in the present embodiment, an example has been described in which the integrated gasification combined cycle power generation facility 10 is additionally installed on the same site as the existing boiler 30, but the present disclosure is not limited to this. For example, the integrated gasification combined cycle power generation facility 10 may be installed near the existing boiler 30 and connected to the system by a pipeline or the like. In particular, char is a solid, and as a means of transportation, it can be transported by conveyor or truck in addition to a pipeline. Furthermore, the boiler 30 can also be additionally installed on the same site as or near the existing integrated gasification combined cycle power generation facility 10. Furthermore, the existing boiler 30 and the existing or new integrated gasification combined cycle power generation facility 10 may be connected by a pipeline or the like. In particular, the latest integrated gasification combined cycle power generation facilities 10 are often installed near the existing boiler 30 in consideration of the supply of fuel, and in order to reduce costs, they are often systems that do not have a spare mill 82, so it is easy to obtain the effects of redundancy and improved reliability by sharing the fuel supply facility 80.

[0078] Furthermore, for example, as shown in Fig. 4, an existing boiler 30 may be used instead of the heat recovery steam generator 20. In this case, as shown in Fig. 4, exhaust gas discharged from the gas turbine 17 is supplied to a combustion gas passage 32 of the boiler 30. In this case, the control device 96 may perform control so that the amount of fuel supplied to the boiler 30 is changed depending on the amount and temperature of the exhaust gas from the gas turbine 17. In this case, as shown in Fig. 4, the heat recovery steam generator 20 and the denitration equipment 22 provided downstream of the gas turbine 17 are omitted. In this case, environmental equipment such as the denitration equipment can be shared with the boiler 30, thereby simplifying the configuration of the integrated plant 1.

[0079] Furthermore, in the above embodiment, an example in which only one pulverized fuel hopper 84 is used has been described, but the present disclosure is not limited to this. As described in the above embodiment, it is preferable that the pulverized fuel hopper 84 be a system in which all of the pulverized fuel is temporarily stored in a single hopper and the pulverized fuel is distributed from there to each burner 35, but it is also possible to provide a plurality of pulverized fuel hoppers 84. In this case, when a problem occurs or maintenance occurs with the pulverized fuel hopper 84 or the separator 83, the operation of the integrated plant 1 can be continued by switching the pulverized fuel hopper 84 to be used.

[0080] Furthermore, when multiple pulverized fuel hoppers 84 are provided, as shown in FIG. 5 , a boiler hopper (boiler storage section) 84B for storing pulverized fuel to be supplied to the boiler 30 and a gasifier hopper (gasifier storage section) 84A for storing pulverized fuel to be supplied to the gasifier 101 may be provided separately. The boiler 30 and the gasifier 101 require different levels of pulverization (particle size) of pulverized fuel. Specifically, the gasifier 101 may require pulverized fuel with a relatively large particle size (coarse particles). Therefore, by providing separate boiler hoppers 84B and gasifier hoppers 84A, pulverized fuel with an optimal level of pulverization can be supplied to each of them. This also reduces the pulverization (particle size) of the pulverized fuel to be supplied to the gasifier, thereby reducing the load on the mill 82. This reduces the power consumption of the mill 82 and the number of mills 82 in operation, thereby further improving the energy efficiency of the integrated plant 1.

[0081] In the case where the boiler hopper 84B for storing pulverized fuel to be supplied to the boiler 30 and the gasifier hopper 84A for storing pulverized fuel to be supplied to the gasifier 101 are separately provided, the fuel supply facility 80 may include a classifier 95 provided upstream of the pulverized fuel hopper 84. In this case, the pulverized fuel guided from the mill 82 is guided to the classifier 95 via a pulverized fuel line 86. The classifier 95 is provided above the gasifier hopper 84A. The classifier 95 is, for example, a rotary classifier having multiple rotating blades 95a inside, which knock down coarse particles. The knocked-down coarse particles are introduced into the gasifier hopper 84A located below the classifier 95 (see dashed arrow A in FIG. 5). On the other hand, the fine particles pass between the blades 95a and are discharged to the outside of the classifier 95 through outlet openings formed inside the multiple blades 95a, and are introduced into the separator 83 (see arrow B in FIG. 5). In the separator 83, the carrier gas and the pulverized fuel are separated. The separated pulverized fuel is introduced into the boiler hopper 84B located below the separator 83.

[0082] With this configuration, the ratio of the pulverized fuel (coarse powder) supplied to the gasifier hopper 84A and the pulverized fuel (fine powder) supplied to the boiler hopper 84B can be easily and freely adjusted by adjusting the rotation speed of the blades 95a of the classifier 95. With this type of system, it is no longer necessary for the mill 82 to separate the pulverized fuel into the gasifier hopper 84A and the boiler hopper 84B, and therefore it is no longer necessary to provide, for example, spare mills for each of the boiler 30 and the gasifier 101, thereby simplifying the configuration of the fuel supply facility 80.

[0083] The composite plant and the method for manufacturing the composite plant described in the above-described embodiment can be understood, for example, as follows. A composite plant according to one embodiment of the present disclosure includes: a gasification furnace (101) that generates a generated gas by gasifying a carbon-containing solid fuel; a boiler (30) that combusts the carbon-containing solid fuel to generate steam; a separation unit (15) that separates the generated gas discharged from the gasification furnace (101) from char contained in the generated gas; a char return line (46) that supplies the char separated in the separation unit (15) to the gasification furnace (101); a char supply line (47) that supplies the char separated in the separation unit (15) to the boiler (30); an adjustment unit (47a) that adjusts the amount of char supplied to the boiler (30) via the char supply line (47); and a control unit (96) that, when the amount of char supplied to the gasification furnace (101) exceeds a predetermined threshold, controls the adjustment unit (47a) so that an amount of char exceeding the predetermined threshold is supplied to the boiler (30).

[0084] In the above configuration, a control unit is provided that controls the adjustment unit so that, when the amount of char supplied to the gasification furnace exceeds a predetermined threshold, the amount of char exceeding the predetermined threshold is supplied to the boiler. This stabilizes the amount of char returned to the gasification furnace, thereby stabilizing combustion in the gasification furnace.

[0085] Furthermore, a composite plant according to one embodiment of the present disclosure includes a pulverizer (82) that pulverizes a carbon-containing solid fuel, and the carbon-containing solid fuel pulverized by the pulverizer (82) is supplied to both the gasifier (101) and the boiler (30).

[0086] In the above configuration, the carbon-containing solid fuel pulverized by the pulverizer is supplied to both the gasifier and the boiler. That is, the pulverizer is shared by the gasifier and the boiler. This reduces the number of devices provided in the combined plant and simplifies the equipment compared to when a pulverizer for pulverizing the carbon-containing solid fuel to be supplied to the gasifier and a pulverizer for pulverizing the carbon-containing solid fuel to be supplied to the boiler are provided separately. Therefore, the installation area of ​​the combined plant can be reduced. Furthermore, the initial cost of the combined plant can be reduced. Furthermore, the number of devices that require maintenance can be reduced, thereby reducing running costs.

[0087] Furthermore, a composite plant according to one embodiment of the present disclosure includes a gasification furnace (101) that generates a product gas by gasifying a carbon-containing solid fuel, a boiler (30) that burns the carbon-containing solid fuel to generate steam, a separation section (15) that separates the product gas discharged from the gasification furnace (101) from char contained in the product gas, a char return line (46) that supplies the char separated in the separation section (15) to the gasification furnace (101), a char supply line (47) that supplies the char separated in the separation section (15) to the boiler (30), and a pulverizer (82) that pulverizes the carbon-containing solid fuel, and the carbon-containing solid fuel pulverized in the pulverizer (82) is supplied to both the gasification furnace (101) and the boiler (30).

[0088] In addition, a composite plant according to one embodiment of the present disclosure is provided with a pulverized fuel storage section (84) that receives a supply of pulverized fuel, which is a carbon-containing solid fuel pulverized by the pulverizer (82), and stores the pulverized fuel, and the boiler (30) is supplied with the pulverized fuel stored in the pulverized fuel storage section (84).

[0089] In a configuration without a pulverized fuel storage section, the pulverizer and the boiler are directly connected. In this case, the gas used in the pulverizer (hereinafter referred to as "carrier gas") to transport and dry the pulverized fuel used in the pulverizer is directly introduced into the boiler together with the pulverized fuel and used as primary air when burning the pulverized fuel. Therefore, for example, if the temperature or flow rate of the carrier gas is increased to dry a carbon-containing solid fuel that contains a high moisture content, the amount of primary air supplied to the boiler also increases, which can cause various problems, such as an increase in nitrogen oxides generated in the boiler. On the other hand, in the above configuration, the pulverized fuel stored in the pulverized fuel storage unit is supplied to the boiler. That is, the pulverized fuel storage unit is provided between the pulverizer and the boiler. This prevents the pulverizer and the boiler from being directly connected, and prevents the carrier gas used in the pulverizer from being introduced to the boiler. Therefore, even if the pulverizer transports the pulverized fuel with carrier gas of an amount and temperature appropriate for the properties of the pulverized fuel, the occurrence of problems in the boiler can be suppressed.

[0090] In addition, in a composite plant according to one embodiment of the present disclosure, the pulverized fuel storage section (84) has a boiler storage section (84B) in which the pulverized fuel to be supplied to the boiler (30) is stored, and a gasification furnace storage section (84A) in which the pulverized fuel to be supplied to the gasification furnace (101) is stored.

[0091] In the above configuration, the pulverized fuel storage unit includes a boiler storage unit that stores pulverized fuel to be supplied to the boiler, and a gasifier storage unit that stores pulverized fuel to be supplied to the gasifier. This allows pulverized fuels with different properties to be stored in the boiler storage unit and the gasifier storage unit. Therefore, pulverized fuels with different properties can be supplied to the boiler and the gasifier. Therefore, pulverized fuels with optimal properties can be supplied to the boiler and the gasifier, and the pulverized fuel can be burned appropriately in the boiler and the gasifier. The desired property is, for example, the degree of fineness of the pulverized fuel. For example, pulverized fuel with a low degree of fineness may be stored in the boiler storage section, and pulverized fuel with a high degree of fineness may be stored in the gasifier storage section. In this way, pulverized fuel with a lower degree of fineness can be supplied to the boiler, and the pulverized fuel can be burned suitably in the boiler.

[0092] The composite plant according to an aspect of the present disclosure also includes a product gas line (54) that supplies a portion of the product gas generated in the gasification furnace (101) to the boiler (30).

[0093] The above-described configuration includes a product gas line that supplies the product gas generated in the gasifier to the boiler. As a result, for example, when excess product gas is generated in the gasifier, the excess product gas can be supplied to the boiler via the product gas line and combusted in the boiler. Because the product gas can be combusted in an existing boiler, the number of devices required in the integrated plant can be reduced and the equipment can be simplified compared to when a separate device (e.g., a ground flare) is installed to combust the excess product gas. This reduces the installation area of ​​the integrated plant. Furthermore, the initial cost of the integrated plant can be reduced. Furthermore, by burning the excess product gas in the boiler, the energy of the excess product gas can be used for power generation, etc., thereby improving the energy efficiency of the integrated plant as a whole compared to when a device (e.g., a ground flare) is installed solely to combust the product gas.

[0094] A method for manufacturing a composite plant according to one aspect of the present disclosure is a method for manufacturing a composite plant (1) including a gasification furnace (101) that generates a generated gas by gasifying a carbon-containing solid fuel and a boiler (30) that burns the carbon-containing solid fuel to generate steam, the method including a gasification furnace (101) installation step of installing the gasification furnace (101); a separation unit (15) installation step of installing a separation unit (15) in the gasification furnace (101) that separates the generated gas discharged from the gasification furnace (101) from char contained in the generated gas; a char return line (46) installation step of installing a char return line (46) that supplies the char separated in the separation unit (15) to the gasification furnace (101); a char supply line (47) installation step of installing a char supply line (47) that supplies the char separated in the separation unit (15) to the boiler (30) so as to connect the existing boiler (30) and the separation unit (15); and a fuel supply unit installation step of installing a fuel supply unit (80) that supplies a carbon-containing solid fuel to both the gasification furnace (101) and the boiler (30).

[0095] In the above configuration, a gasification furnace and the like are added to an existing boiler. This allows a composite plant to be manufactured using the existing boiler, which reduces manufacturing costs compared to when a new boiler is installed. [Explanation of symbols]

[0096] 1: Complex plant 10: Gasification combined cycle power generation facility 15: Char separation device (separation section) 16: Gas purification equipment 17: Gas turbine 18: Steam turbine 19: Steam turbine generator 20: Waste heat recovery boiler 21: Gas turbine generator 22:Denitrification equipment 23: First steam line 24: Second steam line 25: Third steam line 26: First water supply line 27: Second water supply line 28: Third water supply line 30: Boiler 31: Furnace 32: Combustion gas passage 33: Flue 34: Char burner 35: Burner 36: Produced gas burner 37: Denitrification equipment 38: Desulfurization equipment 39: Chimney 46: Char return line 47: Char supply line 47a: Flow control valve (adjustment part) 49: First produced gas line 53: Second produced gas line 54: Produced gas supply line 66: Fuel gas supply line 70: Exhaust gas line 73: Condenser 80: Fuel supply equipment (fuel supply section) 81: Banka 82: Mill (crusher) 83:Separator 84: Pulverized fuel hopper (pulverized fuel storage section) 84A: Gasifier hopper (gasifier storage section) 84B: Boiler hopper (boiler storage section) 85: Pressure hopper 86: Pulverized fuel line 87: First pulverized fuel supply line 88: Second pulverized fuel supply line 90: Solid fuel receiving facility 91: Storage facilities 95: Classifier 95a: Blade 101: Gasifier

Claims

1. a gasification furnace that gasifies a carbon-containing solid fuel to generate a product gas; a boiler that burns a carbon-containing solid fuel to generate steam; a separation unit that separates the generated gas discharged from the gasification furnace from char contained in the generated gas; a char return line that supplies the char separated in the separation section to the gasification furnace; a char supply line that supplies the char separated in the separation unit to the boiler; an adjusting unit that adjusts the amount of char supplied to the boiler through the char supply line; a generator having a gas turbine that is rotationally driven by combustion of fuel gas refined from the product gas separated in the separation section; a pulverizer for pulverizing the carbon-containing solid fuel; a control unit, The control unit controls the adjustment unit to supply the amount of char exceeding a predetermined threshold to the boiler when the amount of char supplied to the gasification furnace exceeds the predetermined threshold, and when the gas turbine makes an emergency stop, the supply destination of the generated gas and the char is switched to the boiler and the amount of pulverized carbon-containing solid fuel fed to the boiler is reduced.

2. A composite plant as described in claim 1, wherein the carbon-containing solid fuel pulverized by the pulverizer is supplied to both the gasification furnace and the boiler.

3. a gasification furnace that gasifies a carbon-containing solid fuel to generate a product gas; a boiler that burns a carbon-containing solid fuel to generate steam; a separation unit that separates the generated gas discharged from the gasification furnace from char contained in the generated gas; a char return line that supplies the char separated in the separation section to the gasification furnace; a char supply line that supplies the char separated in the separation unit to the boiler; a pulverizer for pulverizing the carbon-containing solid fuel; a generator having a gas turbine that is rotationally driven by combustion of fuel gas refined from the product gas separated in the separation section; a control unit, The carbon-containing solid fuel pulverized by the pulverizer is supplied to both the gasifier and the boiler, The control unit switches the supply destination of the generated gas and the char to the boiler when the gas turbine makes an emergency stop, and reduces the amount of pulverized carbon-containing solid fuel fed to the boiler.

4. a pulverized fuel storage section that stores the pulverized fuel, which is a carbon-containing solid fuel pulverized by the pulverizer; The boiler is supplied with the pulverized fuel stored in the pulverized fuel storage section, A complex plant as described in claim 2 or claim 3, wherein the control unit controls the amount of pulverized carbon-containing solid fuel stored in the pulverized fuel storage unit to be balanced at a specified level when the gas turbine is stopped in an emergency.

5. The complex plant according to claim 4, wherein the pulverized fuel storage section includes a boiler storage section for storing the pulverized fuel to be supplied to the boiler, and a gasification furnace storage section for storing the pulverized fuel to be supplied to the gasification furnace.

6. 6. The composite plant according to claim 1, further comprising a generated gas line that supplies a portion of the generated gas generated in the gasification furnace to the boiler.

7. A method for manufacturing a composite plant including a gasifier that generates a generated gas by gasifying a carbon-containing solid fuel and a boiler that burns the carbon-containing solid fuel to generate steam, a gasification furnace installation step of installing the gasification furnace; a separation unit installation step of installing a separation unit in the gasification furnace to separate the generated gas discharged from the gasification furnace from char contained in the generated gas; a char return line installation step of installing a char return line that supplies the char separated in the separation section to the gasification furnace; a pulverizer installation step of installing a pulverizer that pulverizes the carbon-containing solid fuel; a generator installation step of installing a generator having a gas turbine that is rotationally driven by combustion of fuel gas refined from the product gas separated in the separation section; a control device installation process for installing a control device that switches the supply destination of the generated gas and the char to the boiler when the gas turbine is stopped in an emergency and controls the amount of pulverized carbon-containing solid fuel fed to the boiler to be reduced; a char supply line installation step of installing a char supply line that supplies the char separated in the separation unit to the boiler so as to connect the existing boiler and the separation unit; and a fuel supply unit installation step of installing a fuel supply unit that supplies a carbon-containing solid fuel to both the gasification furnace and the boiler.

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