JP7455781B2 - Ammonia supply unit for power generation plants, ammonia vaporization treatment method for power generation plants, and power generation plants - Google Patents

Description

The present disclosure relates to an ammonia supply unit for a power plant, an ammonia vaporization treatment method for a power plant, and a power plant.

Patent Document 1 discloses a power generation plant in which liquefied natural gas (hereinafter referred to as LNG) is used as fuel, and a condenser is connected to an LNG vaporizer via a refrigerant pipe. Heat from the steam flowing into the condenser from the turbine is recovered by the cooling water flowing through the refrigerant pipe, and the cooling water from which the heat has been recovered flows into the LNG vaporizer and is used for vaporizing LNG.

Japanese Patent Application Publication No. 8-200017

The above-mentioned patent document does not disclose a configuration for vaporizing liquid ammonia, nor does it disclose a configuration for securing the amount of heat for vaporizing liquid ammonia. Furthermore, inside the condenser of the above patent document, heat exchange only takes place between the steam that has passed through the turbine and the cooling water flowing through the refrigerant piping, so the condensate treatment within the condenser is insufficient. There is a risk that In this case, the pressure inside the condenser may not be sufficiently reduced, which may reduce power generation efficiency.

An object of the present disclosure is to provide an ammonia supply unit for a power generation plant, an ammonia vaporization treatment method for a power generation plant, and a power generation plant that can secure the amount of heat for vaporizing liquid ammonia and improve the thermal efficiency of the heat cycle. That's true.

According to at least one embodiment of the present disclosure, an ammonia supply unit for a power plant includes:
The steam turbine is provided with at least one ammonia vaporizer for vaporizing liquid ammonia, the ammonia vaporizer being provided inside a condenser for condensing steam discharged from the turbine.

An ammonia vaporization treatment method for a power plant according to at least one embodiment of the present disclosure includes:
A vaporization process is provided in which liquid ammonia is vaporized using at least one ammonia vaporizer provided inside a condenser for condensing steam from the turbine.

A power generation plant according to at least one embodiment of the present disclosure includes:
boiler and
a turbine for rotating using steam from the boiler as a power source;
a generator for generating electricity by rotating the turbine;
a condenser for condensing steam discharged from the turbine;
at least one ammonia vaporizer provided inside the condenser for vaporizing liquid ammonia;
Equipped with

According to the present disclosure, it is possible to provide an ammonia supply unit for a power generation plant, an ammonia vaporization treatment method for a power generation plant, and a power generation plant that can secure the amount of heat for vaporizing liquid ammonia and improve the thermal efficiency of the heat cycle. .

FIG. 1 is a schematic diagram representing a boiler according to an embodiment of the present disclosure. 1 is a schematic diagram of a power plant according to an embodiment of the present disclosure. FIG. 1 is a schematic diagram showing an ammonia supply unit according to a first embodiment of the present disclosure. It is a graph conceptually showing the operation periods of two vaporizers according to an embodiment of the present disclosure. FIG. 3 is a schematic diagram showing an ammonia supply unit according to a second embodiment of the present disclosure. FIG. 3 is a schematic diagram showing an ammonia supply unit according to a third embodiment of the present disclosure. 1 is a flowchart showing an ammonia vaporization treatment method for a power plant according to an embodiment of the present disclosure. 3 is a flowchart showing a vaporization process according to an embodiment of the present disclosure.

Hereinafter, preferred embodiments according to the present disclosure will be described with reference to the drawings. It should be noted that the present invention is not limited to this embodiment, and if there are multiple embodiments, the present invention may be configured by combining each embodiment. In the following description, the term "above" or "upper" refers to the upper side in the vertical direction, and "lower" or "lower" refers to the lower side in the vertical direction, and the vertical direction is not exact and includes errors.
Furthermore, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples. do not have.
For example, expressions expressing relative or absolute positioning such as "in a certain direction,""along a certain direction,""parallel,""orthogonal,""centered,""concentric," or "coaxial" are strictly In addition to representing such an arrangement, it also represents a state in which they are relatively displaced with a tolerance or an angle or distance that allows the same function to be obtained.
For example, expressions such as "same,""equal," and "homogeneous" that indicate that things are in an equal state do not only mean that things are exactly equal, but also have tolerances or differences in the degree to which the same function can be obtained. It also represents the existing state.
For example, expressions expressing shapes such as squares and cylinders do not only refer to shapes such as squares and cylinders in a strict geometric sense, but also include uneven parts and chamfers to the extent that the same effect can be obtained. Shapes including parts, etc. shall also be expressed.
On the other hand, the expressions "comprising,""including," or "having" one component are not exclusive expressions that exclude the presence of other components.
Note that similar configurations may be designated by the same reference numerals and explanations may be omitted.

<Overview of boiler 10 and power plant 1>
FIG. 1 is a schematic diagram illustrating a boiler according to an embodiment of the present disclosure.

A boiler 10 according to an embodiment of the present disclosure uses pulverized coal obtained by pulverizing coal (carbon-containing solid fuel) as pulverized fuel, combusts this pulverized fuel with a burner, and uses the heat generated by this combustion as feed water or steam. This is a coal-fired (pulverized coal-fired) boiler that can exchange heat and generate superheated steam. In addition to the pulverized fuel, the boiler 10 of this embodiment uses a burner to burn ammonia gas generated by vaporizing liquid ammonia. Therefore, in the boiler 10 of this embodiment, co-firing of pulverized coal and ammonia gas is performed.

In this embodiment, as shown in FIG. 1, the boiler 10 includes a furnace 11, a combustion device 12, and a combustion gas passage 13. The furnace 11 has a hollow rectangular tube shape and is installed along the vertical direction. The furnace wall 101 constituting the furnace 11 is composed of a plurality of heat transfer tubes and fins connecting these, and transfers heat generated by combustion of at least one of pulverized fuel and ammonia gas to water and steam flowing inside the heat transfer tubes. The temperature rise of the furnace wall 101 is suppressed by exchanging heat with the furnace wall 101.

The combustion device 12 is provided on the lower side of the furnace wall 101 that constitutes the furnace 11 . In this embodiment, the combustion device 12 includes a plurality of burners (for example, 21, 22, 23, 24, 25) mounted on the furnace wall 101. For example, the burners 21, 22, 23, 24, 25 are arranged at equal intervals along the circumferential direction of the furnace 11 as one set, and are arranged in multiple stages along the vertical direction (for example, five stages in FIG. 1). It is located. However, the shape of the furnace, the number of burners in one stage, the number of stages, the arrangement, etc. are not limited to this embodiment.

The burners 21, 22, 23 are connected to an ammonia gas supply pipe 69. The ammonia gas supply pipe 69 is a component of an ammonia supply unit 60 for a power generation plant (hereinafter sometimes simply referred to as the ammonia supply unit 60) for generating ammonia gas by vaporizing liquid ammonia. Details of the ammonia supply unit 60 will be described later.

The burners 24 and 25 are connected to a plurality of crushers (mills) 34 and 35 via pulverized coal supply pipes 29 and 33 (hereinafter, the crushers 34 and 35 may be collectively referred to as the crusher 3). be). In this pulverizer 3, for example, a pulverizing table (not shown) is rotatably supported within the housing, and a plurality of pulverizing rollers (not shown) are supported above the pulverizing table so as to be rotatable in conjunction with the rotation of the pulverizing table. has been configured. When the coal is placed between the plurality of crushing rollers and the crushing table, it is crushed and conveyed to a classifier (not shown) in the housing of the crusher 3 by a conveying gas (primary air, oxidizing gas). The pulverized fuel classified into a predetermined particle size range can be supplied to the burners 24 and 25 from the pulverized coal supply pipes 29 and 33. Note that the carrier gas also plays the role of drying the pulverized fuel.

The above-mentioned conveying gas is sent to the crusher 3 via the air pipe 30 from a primary air fan 31 (PAF) that takes in outside air. The air pipe 30 includes a hot air guide pipe 30A through which hot air heated by the air heater 42 flows out of the air sent out from the primary air ventilator 31, and a hot air guide pipe 30A through which hot air heated by the air heater 42 flows out of the air sent out from the primary air ventilator 31; It includes a cold air guide pipe 30B through which cold air close to room temperature flows without passing through the air, and a conveying gas flow path 30C through which hot air and cold air merge and flow. The hot air guide pipe 30A and the cold air guide pipe 30B are provided with a hot air damper 30D and a cold air damper 30E, respectively. By adjusting the opening degree of each of these dampers according to the supply conditions of the pulverized coal fuel, the flow rate and temperature of the transport gas flowing through the transport gas flow path 30C are adjusted. In this embodiment, the transport gas flowing through the transport gas flow path 30C includes hot air from the hot air guide pipe 30A. That is, the air pipe 30 is configured to guide hot air heated by the air heater 42 to the crusher 3 that crushes coal as fuel.

Further, the furnace 11 is provided with a wind box 36 at the mounting positions of the burners 21, 22, 23, 24, and 25, and one end portion of an air duct (wind path) 37 is connected to this wind box 36. The air duct 37 is provided with a forced draft fan (FDF) 38 at the other end.

The combustion gas passage 13 is connected to the upper part of the furnace 11 in the vertical direction, as shown in FIG. The combustion gas passage 13 is provided with superheaters 102, 103, 104, reheaters 105, 106, and a economizer 107 as heat exchangers for recovering the heat of the combustion gas, and the heat generated in the furnace 11 is Heat exchange occurs between the combustion gas and the feed water or steam flowing inside each heat exchanger.

As shown in FIG. 1, the combustion gas passage 13 is connected to a flue 14 on its downstream side through which the combustion gas that has undergone heat exchange is discharged. The flue 14 is provided with an air heater (air preheater) 42 for heating the air flowing through each of the air duct 37 and the air pipe 30. In the air heater 42, heat exchange is performed between the outside air flowing through the air duct 37 and the combustion gas flowing through the flue 14 to raise the temperature of the combustion air supplied to the burners 21, 22, 23, 24, and 25. I can do it. Further, in the air heater 42, heat exchange is performed between the outside air flowing toward the hot air guide pipe 30A and the combustion gas flowing through the flue 14, so that the outside air can be changed into hot air. Therefore, it is understood that the air heater 42 is configured to heat the outside air using the exhaust heat of the boiler 10.

Further, the flue 14 is provided with a denitrification device 43 at a position upstream of the air heater 42 . The denitrification device 43 supplies a reducing agent, such as ammonia or urea water, that has the effect of reducing nitrogen oxides into the flue 14, and causes a reaction between the nitrogen oxides in the combustion gas to which the reducing agent is supplied and the reducing agent. This is promoted by the catalytic action of the denitrification catalyst installed in the denitrification device 43, thereby removing and reducing nitrogen oxides in the combustion gas. Note that the ammonia gas supply pipe 69 described above may be connected to the denitrification device 43. That is, the ammonia gas supplied from the ammonia supply unit 60 may be used as a reducing agent. The ammonia supply unit 60 in this case is illustrated by a two-dot chain line in FIG.
The gas duct 41 connected to the flue 14 is provided with a dust collector 44 such as an electric precipitator, an induced draft fan (IDF) 45, a desulfurization device 46, etc. at a position downstream from the air heater 42. A chimney 50 is provided at the end.

On the other hand, when the plurality of crushers 34, 35 (3) are driven, the generated pulverized fuel is supplied to the burners 24, 25 through the pulverized coal supply pipes 29, 33 together with the conveying gas (primary air, oxidizing gas). Ru. In addition, by exchanging heat with the exhaust gas discharged from the flue 14 and the air heater 42, heated combustion air (secondary air, oxidizing gas) is passed from the air duct 37 through the wind box 36 to the burner 21, 22, 23, 24, and 25. The burners 24 and 25 blow a pulverized fuel mixture, which is a mixture of pulverized fuel and transport gas, into the furnace 11 and blow combustion air into the furnace 11, and at this time, the pulverized fuel mixture ignites to form a flame. can do. A flame is generated in the lower part of the furnace 11 , and high-temperature combustion gas rises within the furnace 11 and is discharged into the combustion gas passage 13 . Simultaneously with the start of the injection of the pulverized fuel mixture (or after the ignition of the pulverized fuel mixture), the burners 21, 22, and 23 inject ammonia gas into the furnace 11, causing combustion of the ammonia gas and the combustion of pulverized coal and ammonia. Mixed firing is performed. Note that air is used as the oxidizing gas in this embodiment. It may have a higher or lower oxygen content than air, and can be used by optimizing the fuel flow rate.

Thereafter, as shown in FIG. ), the second reheater 106, the first reheater 105 (hereinafter sometimes simply referred to as a reheater), and the economizer 107, and then the nitrogen oxides are reduced and removed by the denitrification device 43. After particulate matter is removed by a dust collector 44 and sulfur oxides are removed by a desulfurizer 46, the smoke is discharged into the atmosphere from a chimney 50. Note that the heat exchangers do not necessarily have to be arranged in the order described above with respect to the combustion gas flow.

Note that FIG. 1 does not accurately show the positions of the heat exchangers (superheaters 102, 103, 104, reheaters 105, 106, and economizer 107) in the combustion gas passage 13, but The arrangement order of the exchanger with respect to the combustion gas flow is also not limited to the description in FIG.

FIG. 2 is a schematic diagram of a power plant according to an embodiment of the present disclosure. The power generation plant 1 of this embodiment includes, as an example, a boiler 10 including each of the heat exchangers described above, a turbine 110 for rotating using steam from the boiler 10 as a power source, and a power generation unit for generating electricity by rotating the turbine 110. a condenser 114 for condensing the steam discharged from the turbine 110; a boiler feed pump 123 for sending the condensed water condensed by the condenser 114 to the boiler 10; A supply unit 60 is provided. Boiler 10, turbine 110, condenser 114, and boiler feed pump 123 form a prescribed thermal cycle (eg, Rankine cycle). The work extracted from turbine 110 during this thermal cycle causes generator 115 to generate electrical power. The circulating heat medium in this thermal cycle is water that circulates at a pressure and temperature above the triple point.
In one embodiment, all of the above-mentioned components of the power plant 1 except for the ammonia supply unit 60 are existing equipment, and the ammonia supply unit 60 is added to these existing equipment.

The turbine 110 of this embodiment includes, for example, a high-pressure turbine 111, an intermediate-pressure turbine 112, and a low-pressure turbine 113, and includes reheaters 105 and 106 that recover heat from the combustion gas flowing through the combustion gas passage 13 (see FIG. 1). The high pressure turbine 111 and the intermediate pressure turbine 112 are connected to each other via the high pressure turbine 111 and the intermediate pressure turbine 112. A condenser 114 is connected to the low pressure turbine 113 . Condenser 114 houses heat transfer tubes 117 configured to allow cooling water to flow therethrough. The cooling water is, for example, seawater, freshwater, or brackish water. At least one ammonia vaporizer 61, which is a component of the ammonia supply unit 60, is provided inside the condenser 114 of this embodiment. The ammonia vaporizer 61 is configured to vaporize liquid ammonia. The steam that has rotated the low-pressure turbine 113 flows into the condenser 114, where it is cooled by cooling water and liquid ammonia and becomes condensed water. At this time, liquid ammonia is vaporized in the ammonia vaporizer 61 to generate ammonia gas.

Condenser 114 is connected to energy saver 107 via water supply line L1. The water supply line L1 is provided with, for example, a condensate pump (CP) 121, a low pressure water heater 122, a boiler water pump (BFP) 123, and a high pressure water heater 124. A part of the steam that drives the turbines 111, 112, 113 (110) is extracted to the low-pressure feed water heater 122 and the high-pressure feed water heater 124, and is supplied to the high-pressure feed water heater 124 and the low-pressure feed water heater 124 via an air extraction line (not shown). 122 as a heat source, and the water supplied to the economizer 107 is heated.

In the embodiment described above, the boiler 10 is a coal-fired boiler in which co-firing with ammonia gas is performed, but it may be a coal-fired boiler. In this case, the ammonia supply unit 60 may be configured to supply ammonia gas as a reducing agent to the flue 14.
Further, the fuel used in the boiler 10 may be solid fuel such as biomass fuel, PC (petroleum coke) fuel generated during petroleum refining, or petroleum residue. In addition, not only solid fuels can be used as fuels, but also petroleum oils such as heavy oil, light oil, and heavy oil, and liquid fuels such as factory waste liquids.Furthermore, gaseous fuels (natural gas, by-product gases, etc. ) can also be used. Furthermore, it can also be applied to co-fired boilers that use a combination of these fuels.
In addition to the fuel for the boiler 10, the vaporized ammonia gas may be used as a fuel for other power generation means (such as gas turbine power generation). Furthermore, ammonia gas vaporized in the condenser 114 installed in the gas turbine combined cycle plant may be used as fuel for the gas turbine.

<First example of details of ammonia supply unit 60>
FIG. 3 is a schematic diagram showing an ammonia supply unit according to the first embodiment of the present disclosure. Prior to a detailed explanation of the ammonia supply unit 60A (60) according to the first embodiment, the condenser 114 will be explained in detail. Condenser 114 includes a first container 81 that houses heat exchanger tubes 117 . Condenser 114 is arranged directly below turbine 110 (low pressure turbine 113).
The ammonia supply unit 60A (60) according to the first embodiment includes an ammonia tank 71 that stores liquid ammonia, at least one ammonia vaporizer 61 provided inside the condenser 114, and ammonia supply unit 60A (60) that stores liquid ammonia. A supply line 72 for supplying liquid ammonia to the vaporizer 61 and a supply pump 73 provided in the supply line 72 are provided. As an example, the ammonia vaporizer 61 is a heat exchanger tube provided inside the first container 81 of the condenser 114, and the liquid ammonia supplied from the ammonia tank 71 as the supply pump 73 is driven flows through the heat exchanger tube. It vaporizes.

In this embodiment, the steam flowing into the first container 81 of the condenser 114 from the turbine 110 (low-pressure turbine 113) exchanges heat with the cooling water flowing through the heat transfer tube 117 described above, and the ammonia vaporizer Heat is exchanged with liquid ammonia flowing through 61. As a result, the steam in the condenser 114 is condensed to produce condensed water, and the liquid ammonia in the ammonia vaporizer 61 is vaporized to produce ammonia gas. Ammonia gas is discharged from the ammonia vaporizer 61 and supplied to the boiler 10, for example.

Note that the heat transfer tube 117 or the ammonia vaporizer 61 may be immersed in condensed water collected at the bottom of the condenser 114 (not shown). For example, when the ammonia vaporizer 61 is immersed in condensed water, liquid ammonia exchanges heat with the condensed water. Even in this case, the ammonia vaporizer 61 can vaporize liquid ammonia using condensed water as a heat source, and the condenser 114 can condense steam by cooling the condensed water. Moreover, the ammonia vaporizer 61 immersed in the condensed water may be arranged downstream with respect to the heat exchanger tube 117 in the direction in which the steam flows. Furthermore, only one of the plurality of ammonia vaporizers 61 may be arranged downstream with respect to the heat exchanger tubes 117. Further, the ammonia supply unit 60 does not need to include the ammonia tank 71 and the supply pump 73. For example, liquid ammonia may be supplied to the ammonia vaporizer 61 by a large tank truck or a ship that stores liquid ammonia.

According to the above configuration, the ammonia vaporizer 61 vaporizes liquid ammonia using at least one of the steam and condensed water inside the condenser 114 as a direct heat source. Therefore, a heat source for vaporizing liquid ammonia can be secured. At the same time, since liquid ammonia is used in addition to the cooling water for condensate treatment, the condensate treatment in the condenser 114 is accelerated. As a result, the pressure inside the condenser 114 is sufficiently reduced, and the thermal efficiency of a heat cycle, such as a Rankine cycle, including the turbine 110, the condenser 114, and the boiler 10 is improved. Therefore, the ammonia supply unit 60 is realized which can secure the amount of heat for vaporizing liquid ammonia and improve the thermal efficiency of the thermal cycle.
Further, the ratio of the latent heat of vaporization to the calorific value of ammonia is about 6%, which is high compared to fuels such as propane (the ratio of the latent heat of vaporization to the calorific value is about 0.8%). Therefore, when liquid ammonia is vaporized using the steam extracted from the turbine 110 as a heat source, power generation efficiency is likely to decrease. However, in this embodiment, the heat that will be exhausted in the condenser 114 is used to vaporize the liquid ammonia, and the pressure drop in the condenser 114 is promoted, so that the turbine efficiency of the turbine 110 is increased. It is possible to suppress a decrease in power generation efficiency.

In the embodiment illustrated in FIG. 3, the ammonia vaporizer 61 includes two or more vaporizers 61A provided in parallel. In the illustrated embodiment, two vaporizers 61A are provided as heat exchanger tubes. Liquid ammonia supplied from the ammonia tank 71 is vaporized in the process of flowing through one of the vaporizers 61A. The two vaporizers 61A may be operated (vaporization processing) at mutually different timings, or may be operated simultaneously. According to the above configuration, each of the two or more vaporizers 61A provided in parallel discharges ammonia gas having a similar temperature. Therefore, the amount of ammonia gas produced per unit time increases when the temperature reaches the specified temperature.

In this embodiment, the operating states of the two vaporizers 61A are mutually switched. More specifically, the ammonia supply unit 60A includes a switching valve 76 for switching the operating state of each vaporizer 61A. The switching valve 76 in this example is an on-off valve provided in each of the two liquid ammonia supply pipes 74, and the number of switching valves 76 is two. Liquid ammonia from the supply line 72 flows into the liquid ammonia supply pipe 74 with the switching valve 76 open, and is supplied to the vaporizer 61A. Thereby, the vaporizer 61A operates and performs vaporization processing. In addition, in other embodiments, the switching valve 76 may be a three-way valve (flow path switching valve) provided at the connection between the two liquid ammonia supply pipes 74 and the supply line 72. In this case, the number of switching valves 76 is one.

FIG. 4 is a graph conceptually showing operating periods of two vaporizers according to an embodiment of the present disclosure. In this embodiment, the two vaporizers 61A are configured to alternately perform vaporization processing according to the operation of the switching valve 76. In the embodiment illustrated in FIG. 4, the end time of one vaporization process is the same as the start time of the other vaporization process, but in other embodiments, the end time of one vaporization process is the same as the start time of the other vaporization process. The vaporization process for the other one may be started after the first one is vacated.
In still other embodiments, one vaporization process may begin before the other vaporization process ends. This is because if the two vaporizers operate overlappingly for a certain period of time at the time of switching, there will be less variation in the flow rate at the time of switching, and a constant amount of ammonia gas can be stably supplied.

Since the temperature of liquid ammonia is extremely low, there is a risk that steam or condensed water may adhere to the vaporizer 61A during operation as precipitates such as frost or ice. As a more specific example, precipitates adhere to the outer surface of the heat exchanger tube that constitutes the vaporizer 61A. Note that such deposition of precipitates may occur even when the vaporizer 61A is immersed in condensed water.
If the vaporizer 61A continues the vaporization process, there is a risk that precipitates will further accumulate, inhibiting heat transfer to the liquid ammonia, and liquid ammonia may remain in the ammonia gas discharged from the vaporizer 61A. . In this regard, according to the above configuration, there is a time period in which one of the vaporizers 61A performs the vaporization process and the other vaporizer 61A is inactive. In the other vaporizer 61A, the attached precipitates are removed by steam or condensed water inside the condenser 114. Therefore, the ammonia supply unit 60A can continuously and stably perform the vaporization process of liquid ammonia.
In this way, rather than operating all two or more vaporizers 61A installed in parallel at the same time, it is better to selectively switch the operating state of each vaporizer 61A so that the ammonia gas that has reached the specified temperature can be continuously and Can be generated stably.

Returning to FIG. 3, the ammonia supply unit 60A of the first embodiment includes a temperature sensor 78 for detecting the temperature of the ammonia gas on the outlet side of the vaporizer 61A. In the illustrated embodiment, a temperature sensor 78 is provided in each of the two ammonia gas outlet pipes 77. The two ammonia gas outlet pipes 77 are connected to the outlets of the two vaporizers 61A, respectively. In this embodiment, ammonia gas flowing through the two ammonia gas outlet pipes 77 is supplied to the boiler 10 via the ammonia gas supply pipe 69 described above.

The ammonia supply unit 60A includes a controller 90 configured to control the switching valve 76 based on the measurement results of the two temperature sensors 78. However, in FIG. 3, the controller 90 is electrically connected only to the temperature sensor 78 and the switching valve 76 on one side for the sake of easy viewing of the drawing.
The controller 90 includes a processor that executes various calculation processes, and a memory that non-temporarily or temporarily stores various data processed by the processor. The processor is realized by a CPU, GPU, MPU, DSP, various other arithmetic devices, or a combination thereof. The memory is realized by ROM, RAM, flash memory, a combination thereof, or the like. Note that the controller 90 may be configured to control the power generation plant 1.

In order to prevent excessive deposits from accumulating in the ammonia vaporizer 61, the controller 90 is configured to adjust the operating period of the ammonia vaporizer 61 through control of the switching valve 76. The principle is as follows. As more precipitates accumulate in the ammonia vaporizer 61, the amount of heat used to vaporize liquid ammonia decreases, so the outlet temperature of ammonia gas tends to decrease. Therefore, in response to the outlet temperature of the ammonia gas discharged from the ammonia vaporizer 61 in operation meeting a prescribed drop condition (details will be described later), the vaporization process in the ammonia vaporizer 61 in operation is stopped. , the other ammonia vaporizer 61 starts the vaporization process. Thereby, it is possible to automatically switch the ammonia vaporizer 61 that performs the vaporization process and suppress liquid ammonia from being discharged from the ammonia vaporizer 61.

Based on the above principle, the controller 90 of the present embodiment opens the switching valve corresponding to one temperature sensor 78 when it is determined that the outlet temperature measured by one temperature sensor 78 satisfies a prescribed drop condition. The two switching valves 76 are controlled so that one switching valve 76 closes and the other switching valve 76 that is closed opens. This control is realized by sending a control signal from the controller 90 to each switching valve 76.
Note that the above-mentioned drop condition is that the temperature characteristic value specified based on the outlet temperature measured by the temperature sensor 78 falls below a prescribed threshold value. The temperature characteristic value in this embodiment is the same as the outlet temperature measured by the temperature sensor 78. The temperature characteristic value in other embodiments is specified by the temperature sensor 78 measuring the temperature a plurality of times. As a more specific example, the temperature characteristic value is a temperature average value, a predicted temperature value, or a temperature change rate of the exit temperature of ammonia gas. In addition, when the exit temperature of ammonia gas continuously decreases, the above temperature change rate becomes a negative value.

Note that in other embodiments, a single temperature sensor 78 may be provided in the ammonia gas supply pipe 69. Even in this case, if the operating periods of the two vaporizers 61A do not overlap, the outlet temperature of the ammonia gas discharged from the operating vaporizer 61A is detected based on the detection result of this temperature sensor 78. It is possible. Therefore, the controller 90 can control the switching valve 76 based on the detection result of the single temperature sensor 78.

According to the above configuration, the switching valve 76 can be automatically opened and closed depending on the outlet temperature of the ammonia gas. Therefore, excessive accumulation of precipitates in the ammonia vaporizer 61 can be automatically suppressed.

The ammonia supply unit 60A illustrated in FIG. 3 is configured to supply ammonia gas generated by vaporization to the boiler 10. More specifically, the ammonia supply unit 60A includes an ammonia gas supply pipe 69 for supplying ammonia gas vaporized by the ammonia vaporizer 61 to the boiler 10. According to the above configuration, liquid ammonia can be changed into ammonia gas and supplied to the boiler 10 as fuel. Therefore, the heat source in the condenser 114 can be effectively utilized to supply ammonia gas as fuel to the boiler 10.

In the embodiment illustrated in FIG. 3, the first container 81 of the ammonia supply unit 60A accommodates the ammonia vaporizer 61 and the heat exchanger tube 117. Ammonia vaporizer 61 is located upstream of heat exchanger tube 117 in the direction in which steam flows. According to the above configuration, in the condenser 114, heat exchange between the steam and liquid ammonia is performed before heat exchange between the steam and the cooling water. Since heat is transferred from the vapor to the liquid ammonia before being cooled by the cooling water, the amount of heat for vaporizing the liquid ammonia can be secured.

<Second example of details of ammonia supply unit 60>
FIG. 5 is a schematic diagram showing an ammonia supply unit according to a second embodiment of the present disclosure. The ammonia supply unit 60B (60) according to the second embodiment communicates the second container 82 that accommodates at least one ammonia vaporizer 61 with the first container 81 and second container 82 of the condenser 114. A communication pipe 85 is provided. Steam from the turbine 110 (low-pressure turbine 113) flows into the second container 82 via the communication pipe 85. The vapor that has flowed in is condensed by exchanging heat with liquid ammonia flowing through the ammonia vaporizer 61. Therefore, it is understood that the second vessel 82 functions to condense steam from the turbine 110 and thus forms part of the condenser 114 . Condensed water generated in the second container 82 flows into the first container 81 via a drain pipe 83, which is a component of the ammonia supply unit 60B.
Note that in the illustrated embodiment, the communication pipe 85 is connected to the first container 81 and the second container 82, but instead, the communication pipe 85 is connected to the steam flow path 89 between the turbine 110 and the first container 81. It may also be connected to the second container 82. Even in this case, if the downstream end of the steam flow path 89 is connected to the first container 81, the first container 81 and the second container 82 are provided in parallel with each other. In the example of FIG. 5, the ammonia vaporizer 61 includes two vaporizers 61A provided inside the second container 82, but these two vaporizers 61A may be connected in parallel to each other. Further, another ammonia vaporizer 61 may be provided inside the first container 81. That is, the number of ammonia vaporizers 61 may be two or more.

According to the above configuration, even if the first container 81 is an existing facility, the ammonia supply unit 60B can be completed by adding the second container 82, the drain pipe 83, and the communication pipe 85. Therefore, construction of the ammonia supply unit 60B can be facilitated.

In the embodiment illustrated in FIG. 5, the bottom 82A of the second container 82 is provided at a higher position than the bottom 81A of the first container 81. According to the above configuration, the condensed water generated in the second container 82 easily flows into the first container 81 via the drain pipe 83. Therefore, steam or condensed water can be circulated without stagnation.

<Third example of details of ammonia supply unit 60>
FIG. 6 is a schematic diagram showing an ammonia supply unit according to a third embodiment of the present disclosure. Ammonia supply unit 60C (60) according to the third embodiment differs from ammonia supply unit 60B in that a first container 81 and a second container 82 are provided in series. To explain the specific differences in configuration, the steam flow path 89 is connected to the second container 82 instead of the first container 81, and the ammonia supply unit 60C (60) is connected to the communication pipe 85 (see FIG. 5). A communication pipe 86 is provided. The steam passage 89 forms a downstream passage of the turbine 110 (low-pressure turbine 113), and is connected to the turbine 110 and the second container 82. The communication pipe 86 is connected to the second container 82 and the first container 81. Therefore, steam discharged from the turbine 110 flows into the second container 82 via the steam flow path 89. The condensed water generated in the second container 82 flows through the drain pipe 83, and the steam remaining in the condensate treatment in the second container 82 flows into the first container 81 through the communication pipe 86. Condensing steam.

According to the above configuration, even if the first container 81 is an existing equipment, if the connection destination of the steam flow path 89 is changed and the second container 82, the drain pipe 83, and the communication pipe 86 are additionally installed, the ammonia Supply unit 60C is completed. Since additional construction work such as drilling work for the existing first container is reduced, it is possible to realize ease of construction of the ammonia supply unit 60C.

<Example of ammonia vaporization treatment method for power generation plants>
FIG. 7 is a flowchart illustrating an ammonia vaporization treatment method for a power plant according to an embodiment of the present disclosure. FIG. 8 is a flowchart showing a vaporization process according to an embodiment of the present disclosure. The flowcharts shown in FIGS. 7 and 8 are executed by the controller 90 as an example. Further, ammonia gas generated by the ammonia vaporization treatment method described below may be used as either a fuel or a reducing agent. In the following description, a step may be abbreviated as "S".

As shown in FIG. 7, when the ammonia vaporization method for a power generation plant is started, a vaporization process is executed (S11). In the vaporization process, at least one ammonia vaporizer 61 vaporizes liquid ammonia. As a more specific example, in the vaporization process of this example, the operating state of each of two or more vaporizers 61A connected in parallel is switched. Switching of the operating state of each vaporizer 61A is performed by the controller 90 controlling the switching valve 76 based on the detection result of the temperature sensor 78. In the following, an embodiment will be described in which the number of ammonia vaporizers 61 is two, and two switching valves 76 are provided in two liquid ammonia supply pipes 74, respectively.

As shown in FIG. 8, in the vaporization process, first, one of the ammonia vaporizers 61 performs vaporization (S31). The controller 90 transmits a control signal for switching to an open state to one of the two switching valves 76, both of which are closed. As a result, liquid ammonia flows into one of the ammonia vaporizers 61, and vaporization processing of the liquid ammonia is executed. Liquid ammonia generated during the vaporization process is used as fuel for the boiler 10, for example.

Subsequently, it is determined whether the temperature characteristic value specified based on the measurement result of the temperature sensor 78 corresponding to the ammonia vaporizer 61 performing the vaporization process satisfies the drop condition (S33). When the controller 90 determines that the descent condition is not satisfied (33: NO), it is determined whether to end the vaporization process (S35). For example, the controller 90 makes a determination based on whether or not it has received an instruction signal to end the vaporization process sent from the operator. If the controller 90 determines that the vaporization process is not completed (S35: NO), the process returns to S33. Unless excessive precipitates are deposited on the ammonia vaporizer 61 in operation, the descent condition is not satisfied (S33: NO), and while the end instruction signal for the vaporization process is not received (S35: NO), the controller 90 performs S33. , S35 are repeated.

Eventually, when a certain amount of precipitate adheres to the operating ammonia vaporizer 61 and the descent condition is satisfied (S33: YES), the controller 90 switches the ammonia vaporizer 61 that performs the vaporization process (S37). The controller 90 sends a control signal to each of the two switching valves 76 so that the switching valve 76 that is open closes and the switching valve 76 that is closed opens. After that, the process returns to S33. In this manner, the two ammonia vaporizers 61 automatically perform vaporization processing alternately by repeating S31 to S37 by the controller 90.

When it is determined that the vaporization process is to be completed (S35: YES), the controller 90 stops the ammonia vaporizer 61 that is performing the vaporization process (S39). Specifically, the controller 90 sends a control signal to the open switching valve 76 so that the switching valve 76 closes. After the vaporization process is completed, the process returns to the flow illustrated in FIG. 7, and the ammonia vaporization process ends.

<Summary>
The contents described in the several embodiments described above can be understood, for example, as follows.

1) An ammonia supply unit (60) for a power plant according to at least one embodiment of the present disclosure,
At least one ammonia vaporizer (61) is provided inside a condenser (114) for condensing steam discharged from the turbine (110), and for vaporizing liquid ammonia.

According to configuration 1) above, the ammonia vaporizer (61) vaporizes liquid ammonia using at least one of the steam and condensed water inside the condenser (114) as a direct heat source. Therefore, a heat source for vaporizing liquid ammonia can be secured. At the same time, since liquid ammonia is used in addition to cooling water for condensate treatment, condensate treatment in the condenser (114) is accelerated. As a result, the pressure inside the condenser (114) is sufficiently reduced, and the thermal efficiency of the thermal cycle including the turbine (110) and the condenser (114) is improved. Therefore, an ammonia supply unit (60) for a power generation plant that can secure the amount of heat for vaporizing liquid ammonia and improve the thermal efficiency of the thermal cycle is realized.

2) In some embodiments, the ammonia supply unit (60) described in 1) above,
The condenser (114) is
a heat exchanger tube (117) configured to allow cooling water to flow therein;
a first container (81) accommodating the heat exchanger tube (117);
a second container (82) that is provided in communication with the first container (81) to form a part of the condenser (114) and accommodates the at least one ammonia vaporizer (61); .

According to the configuration of 2) above, even if the condenser (114) including the heat exchanger tube (117) and the first container (81) is an existing facility, the installation of the ammonia supply unit (60) is not necessary. It can be made easier.

3) In some embodiments, the ammonia supply unit (60) described in 2) above,
The bottom (82A) of the second container (82) is provided at a higher position than the bottom (81A) of the first container (81).

According to configuration 3) above, condensed water generated in the second container (82) easily flows into the first container (81). Therefore, steam or condensed water can be circulated without stagnation.

4) In some embodiments, the ammonia supply unit (60) described in 1) above,
The condenser (114) is
a heat exchanger tube (117) configured to allow cooling water to flow therein;
a first container (81) containing the heat exchanger tube (117);
including;
The at least one ammonia vaporizer (61) is arranged within the first container (81) upstream of the heat exchanger tube (117).

According to configuration 4) above, in the condenser (114), steam exchanges heat with liquid ammonia before exchanging heat with cooling water. Thereby, the amount of heat for vaporizing liquid ammonia can be secured.

5) In some embodiments, the ammonia supply unit (60) according to any one of 1) to 4) above,
The at least one ammonia vaporizer (61) includes two or more vaporizers (61A) provided in parallel.

According to configuration 5) above, each of the two or more vaporizers (61A) provided in parallel discharges ammonia gas at a similar temperature. Therefore, it is possible to increase the amount of ammonia gas produced per unit time when the temperature reaches the specified temperature.

6) In some embodiments, the ammonia supply unit (60) described in 5) above,
It further includes a switching valve (76) for switching the operating state of each of the vaporizers (61A).

Precipitates such as frost or ice that adhere to the ammonia vaporizer (61) during the vaporization process of liquid ammonia may inhibit heat transfer to the liquid ammonia. In this regard, according to configuration 6) above, by switching the switching valve (76), it is possible to suppress excessive accumulation of precipitates in any of the vaporizers (61A).

7) In some embodiments, the ammonia supply unit (60) described in 6) above,
a temperature sensor (78) for detecting the temperature of ammonia gas on the outlet side of each vaporizer (61A);
The apparatus further includes a controller (90) for controlling the switching valve (76) based on the detection result of the temperature sensor (78).

According to configuration 7) above, the controller (90) controls the switching valve (76) according to the outlet temperature of the ammonia gas, thereby automatically preventing excessive accumulation of precipitates in the vaporizer (61A). can be suppressed to

8) In some embodiments, the ammonia supply unit (60) according to any one of 1) to 7) above,
It further includes an ammonia gas supply pipe (69) for supplying the ammonia gas vaporized by the ammonia vaporizer (61) to the boiler (10).

According to configuration 8) above, liquid ammonia can be changed into ammonia gas and supplied to the boiler (10) as fuel. Therefore, the heat source in the condenser (114) can be effectively utilized to supply ammonia gas as fuel to the boiler (10).

9) An ammonia vaporization treatment method for a power plant according to at least one embodiment of the present disclosure,
At least one ammonia vaporizer (61) provided inside the condenser (114) for condensing the steam from the turbine (110) performs a vaporization process (S11) in which liquid ammonia is vaporized. Be prepared.

According to configuration 9) above, for the same reason as 1) above, an ammonia vaporization method for a power generation plant is realized that can secure the amount of heat for vaporizing liquid ammonia and improve the thermal efficiency of the heat cycle. .

10) In some embodiments, the ammonia vaporization treatment method for a power plant described in 9) above,
The at least one ammonia vaporizer (61) includes two or more vaporizers (61A) connected in parallel to each other,
In the vaporization process (S11), the operating state of each vaporizer (61A) is switched.

According to configuration 10) above, it is possible to suppress excessive accumulation of precipitates in any of the vaporizers (61A).

11) In some embodiments, the ammonia vaporization treatment method for a power plant described in 10) above,
In the vaporization treatment step (S11), each of the vaporizers (61A) is A switching valve (76) for switching the operating state of the controller is controlled.

According to configuration 11) above, the operating state of the vaporizer (61A) can be stably switched by controlling the switching valve (76) based on the temperature of the ammonia gas.

12) The power plant (1) according to at least one embodiment of the present disclosure includes:
Boiler (10) and
a turbine (110) for rotation using steam from the boiler (10) as a power source;
a generator (115) for generating electricity by rotating the turbine (110);
a condenser (114) for condensing the steam discharged from the turbine (110);
at least one ammonia vaporizer (61) provided inside the condenser (114) for vaporizing liquid ammonia;
Equipped with

According to configuration 12) above, for the same reason as 1) above, a power generation plant (1) is realized that can secure the amount of heat for vaporizing liquid ammonia and improve the thermal efficiency of the heat cycle.

1: Power plant 10: Boiler 60: Ammonia supply unit 61: Ammonia vaporizer 61A: Vaporizer 69: Ammonia gas supply pipe 76: Switching valve 78: Temperature sensor 81: First container 81A: Bottom part 82: Second container 82A: Bottom part 83: Drain pipes 85, 86: Communication pipe 89: Steam flow path 90: Controller 110: Turbine 111: Turbine 114: Condenser 115: Generator 117: Heat transfer tube

Claims (13)

At least one ammonia vaporizer provided inside a condenser for condensing the steam discharged from the turbine and vaporizing liquid ammonia ,
The condenser is
a heat exchanger tube configured to allow cooling water to flow therein;
a first container accommodating the heat exchanger tube;
including;
An ammonia supply unit for a power plant, comprising a second vessel in communication with the first vessel forming part of the condenser and accommodating the at least one ammonia vaporizer . The bottom of the second container is provided at a higher position than the bottom of the first container.
An ammonia supply unit for a power plant according to claim 1 . At least one ammonia vaporizer provided inside a condenser for condensing the steam discharged from the turbine and vaporizing liquid ammonia,
The condenser is
a heat exchanger tube configured to allow cooling water to flow therein;
a first container accommodating the heat exchanger tube;
including;
an ammonia supply unit, wherein the at least one ammonia vaporizer is disposed within the first container upstream of the heat exchanger tubes; The at least one ammonia vaporizer includes two or more vaporizers installed in parallel.
An ammonia supply unit for a power generation plant according to any one of claims 1 to 3 . further comprising a switching valve for switching the operating state of each of the vaporizers,
The ammonia supply unit for a power plant according to claim 4 . a temperature sensor for detecting the temperature of ammonia gas on the outlet side of each of the vaporizers;
further comprising a controller for controlling the switching valve based on the detection result of the temperature sensor;
The ammonia supply unit for a power plant according to claim 5 . Further comprising an ammonia gas supply pipe for supplying the ammonia gas vaporized by the ammonia vaporizer to the boiler.
The ammonia supply unit for a power plant according to claim 1 or 3 . A vaporization process of vaporizing liquid ammonia using at least one ammonia vaporizer provided inside a condenser for condensing the steam from the turbine ,
The condenser is
a heat exchanger tube configured to allow cooling water to flow therein;
a first container accommodating the heat exchanger tube;
including;
The at least one ammonia vaporizer is housed in a second container provided in communication with the first container so as to form a part of the condenser . A vaporization process of vaporizing liquid ammonia using at least one ammonia vaporizer provided inside a condenser for condensing the steam from the turbine,
The condenser is
a heat exchanger tube configured to allow cooling water to flow therein;
a first container accommodating the heat exchanger tube;
including;
The at least one ammonia vaporizer is disposed in the first container upstream of the heat exchanger tube. The at least one ammonia vaporizer includes two or more vaporizers connected in parallel to each other,
In the vaporization process, switching the operating state of each vaporizer,
The ammonia vaporization treatment method for a power generation plant according to claim 8 or 9. In the vaporization process, a switching valve for switching the operating state of each vaporizer is controlled based on a detection result of a temperature sensor for detecting the temperature of ammonia gas on the outlet side of each vaporizer. ,
The ammonia vaporization treatment method for a power generation plant according to claim 10. boiler and
a turbine for rotating using steam from the boiler as a power source;
a generator for generating electricity by rotating the turbine;
a condenser for condensing the steam discharged from the turbine;
at least one ammonia vaporizer provided inside the condenser for vaporizing liquid ammonia;
Equipped with
The condenser is
a heat exchanger tube configured to allow cooling water to flow therein;
a first container accommodating the heat exchanger tube;
including;
A power plant comprising a second vessel in communication with the first vessel forming part of the condenser and accommodating the at least one ammonia vaporizer . boiler and
a turbine for rotating using steam from the boiler as a power source;
a generator for generating electricity by rotating the turbine;
a condenser for condensing the steam discharged from the turbine;
at least one ammonia vaporizer provided inside the condenser for vaporizing liquid ammonia;
Equipped with
The condenser is
a heat exchanger tube configured to allow cooling water to flow therein;
a first container accommodating the heat exchanger tube;
including;
The at least one ammonia vaporizer is disposed within the first vessel upstream of the heat exchanger tubes.

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