JPWO2020217885A1 - Power generation equipment - Google Patents

Abstract

The power generation facility 2 includes a boiler 14 that generates steam, a steam turbine 22 that is operated by the steam, a condenser 26 that condenses the exhaust of the steam turbine 22, and a cooler 28 that sends a coolant to the condenser 26. , The pressure gauge 48 for measuring the pressure of the condenser 26, the flowmeter 21 for measuring the flow rate of the exhaust to the condenser 26, and the pressure of the condenser 26 according to the flow rate of the exhaust. A controller 30 for controlling the cooling capacity of the cooler 28 so as to fall within a predetermined range is provided. Preferably, the cooler 28 includes at least one fan 60 that cools the coolant. Preferably, the controller 30 controls the cooling capacity by controlling the number of the fans 60 to be operated or the rotation speed of the fans 60.

Description

The present invention relates to a power generation facility. Specifically, the present invention relates to a power generation facility using exhaust heat.

In a cement plant, a large amount of heat is discharged when the raw material limestone is processed with high heat. In order to make effective use of energy, an increasing number of cement plants are installing power generation equipment to recover this waste heat energy as electric power.

In this power generation facility, waste heat is supplied to the boiler. The liquid heat medium in the boiler becomes high-pressure steam by this heat and is sent to the steam turbine. The steam rotates the blades of the steam turbine to drive the generator. The steam passes through the steam turbine and is sent to the condenser. The coolant sent from the cooler is circulated in the condenser. The vapor is cooled in the condenser and becomes liquid. The liquefied heat medium is returned to the boiler.

When the steam is cooled and liquefied by the condenser, the volume of the steam suddenly decreases, and the inside of the condenser becomes a state close to vacuum. Increasing the cooling capacity of the cooler promotes liquefaction, which reduces the pressure of the condenser and increases the energy difference of steam between the inlet and outlet of the steam turbine. The force that rotates the steam blades increases, and the amount of power generated can be increased. On the other hand, if the amount of power generation becomes excessive due to excessive cooling, the generator may be damaged. Also, if steam liquefaction begins in the steam turbine due to excessive cooling, it can cause damage to the steam turbine.

In the power generation equipment reported in JP-A-2007-6683, the amount of power sent to the coolant introducing means so that the amount of power generation does not exceed a predetermined value in order to increase the effective electric energy while protecting the generator. Is being adjusted.

In the condenser cooling system reported in JP-A-2003-343211, the rotation speed of the pump that circulates the coolant is adjusted so that the degree of vacuum of the condenser becomes a predetermined value. As a result, the power consumption of the pump is reduced while the power generation facility is operated stably.

JP-A-2007-6683 Japanese Patent Application Laid-Open No. 2003-343211

It is important to adjust the pressure of the condenser in order to improve the power generation efficiency while suppressing damage to the power generation equipment. The range of this appropriate pressure depends on the flow rate of steam sent from the turbine to the condenser (turbine exhaust flow rate). In a power generation facility that uses waste heat, the amount of waste heat that can be used fluctuates depending on the operating conditions of the plant, and therefore the turbine exhaust flow rate also fluctuates. Even if the turbine exhaust flow rate fluctuates, there is a demand for power generation equipment that achieves good power generation efficiency while suppressing damage.

An object of the present invention is to provide a power generation facility in which good power generation efficiency is achieved while suppressing damage even if the turbine exhaust flow rate fluctuates.

The power generation equipment according to the present invention includes a boiler that generates steam, a steam turbine that is operated by this steam, a condenser that condenses the exhaust of the steam turbine, a cooler that sends coolant to the condenser, and this condensate. A pressure gauge for measuring the pressure of the condenser, a flowmeter for measuring the flow rate of the exhaust to the condenser, and the cooling so that the pressure of the condenser falls within a predetermined range according to the flow rate of the exhaust. It is equipped with a controller for controlling the cooling capacity of the vessel.

Preferably, the cooler comprises at least one fan for cooling the coolant and at least one pump for circulating the coolant.

Preferably, the controller controls the cooling capacity by controlling the number of the fans to be operated or the rotation speed of the fans.

Preferably, the controller controls the cooling capacity by controlling the number of the pumps to be operated or the rotation speed of the pumps.

Preferably, the power generation facility further comprises a coolant thermometer that measures the temperature of the coolant at the inlet and outlet of the condenser, the controller being the temperature of the condenser, the pressure of the condenser, said. Whether or not the condenser has failed can be determined from the flow rate of the exhaust to the condenser and the flow rate of the coolant obtained from the operating status of the pump.

Preferably, the power generation facility further comprises a coolant thermometer that measures the temperature of the coolant at the inlet and outlet of the condenser, and a water pressure gauge that measures the pressure of the coolant at the inlet of the condenser. The controller can determine the presence or absence of failure of the cooler from the temperature of these coolants, the pressure of the coolant, the pressure of the condenser, and the flow rate of the coolant obtained from the operating state of the pump.

The power generation facility according to the present invention is a controller for controlling the cooling capacity of the cooler so that the pressure of the condenser is within a predetermined range according to the turbine exhaust flow rate obtained from the measurement result by the flow meter. To be equipped. As a result, the pressure of the condenser can be controlled within an appropriate range even if the turbine exhaust flow rate fluctuates. With this power generation facility, good power generation efficiency can be achieved while suppressing damage to the power generation facility.

FIG. 1 is a block diagram showing a power generation facility according to an embodiment of the present invention. FIG. 2 is a block diagram showing the cooler of FIG. FIG. 3 is an example of a graph showing an appropriate condenser pressure range according to the turbine exhaust flow rate. FIG. 4 is a flowchart showing the entire flow of pressure control of the condenser. FIG. 5 is a flowchart showing the pump capacity improving process of the flowchart of FIG. FIG. 6 is a flowchart showing the fan capacity improving process of the flowchart of FIG. FIG. 7 is a flowchart showing the fan capacity reduction process of the flowchart of FIG. FIG. 8 is a flowchart showing the pump capacity reduction process of the flowchart of FIG.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

FIG. 1 is a block diagram showing a power generation facility 2 according to an embodiment of the present invention together with a cement firing facility 4. These are part of the cement plant. The power generation facility 2 generates electricity by utilizing the waste heat from the cement firing facility 4.

The cement firing facility 4 manufactures clinker, which is an intermediate product, from the raw material of cement. As shown in FIG. 1, the cement firing facility 4 includes a preheater 6, a calcining furnace 8, a rotary kiln 10, and an air quenching cooler 12 (AQC12).

The raw material for cement is charged into the preheater 6 and preheated. In this step, high temperature gas is discharged from the preheater 6. In FIG. 1, the gas discharge port of the preheater 6 is indicated by the reference numeral GO1. The temperature of the exhaust gas from the preheater 6 is, for example, about 320 ° C. The preheated raw material is calcined in the calcining furnace 8 and fired in the rotary kiln 10. This fired product is rapidly cooled with AQC12 to obtain clinker. In this step, high temperature gas is discharged from AQC12. In FIG. 1, the gas outlets of AQC12 are indicated by the symbols GO2 and GO3. The temperature of the exhaust gas from the AQC12 is, for example, about 360 ° C.

In the power generation facility 2, the heat medium is steamed by the high-temperature exhaust gas, and the steam drives a steam turbine to generate electricity. A typical heat medium is water. The power generation facility 2 includes a preheater boiler 14 (PH boiler 14), an air quenching cooler boiler (AQC boiler 16), a first flasher 18, a second flasher 20, a steam turbine 22, a generator 24, a flow meter 21, and condensate. It includes a vessel 26, a cooler 28, and a controller 30. In FIG. 1, arrow A represents the flow of exhaust gas. The unsigned arrows represent the flow of the heat carrier.

The PH boiler 14 uses the waste heat from the preheater 6 to generate superheated steam. The PH boiler 14 includes a main body 32 and a steam drum 34. As shown in FIG. 1, the exhaust gas from the exhaust port GO1 of the preheater 6 is introduced into the main body 32 from the inlet 32a of the main body 32 and discharged from the outlet 32b of the main body 32. High-temperature exhaust gas from the preheater 6 is flowing inside the main body 32. A liquid heat medium 36 is stored in the steam drum 34. A liquid heat medium 36 is sent from the steam drum 34 to the inside of the main body 32 and exchanges heat with the exhaust gas to become high-pressure superheated steam. This superheated steam is sent to the steam turbine 22 from the steam output port 38 of the PH boiler 14.

The AQC boiler 16 uses the waste heat from the AQC 12 to generate superheated steam. The AQC boiler 16 includes a main body 40 and a steam drum 42. As shown in FIG. 1, the exhaust gas from the exhaust port GO2 of the AQC12 is introduced into the main body 40 from the inlet 40a of the main body 40 and discharged from the outlet 40b of the main body 40. High-temperature exhaust gas from AQC12 is flowing inside the main body 40. A liquid heat medium 36 is stored in the steam drum 42 of the AQC12. A liquid heat medium 36 is sent from the steam drum 42 to the inside of the main body 40 and exchanges heat with the exhaust gas to become high-pressure superheated steam. The superheated steam is sent to the steam turbine 22 from the steam output port 44 of the AQC boiler 16.

The AQC boiler 16 also has a function of preheating the liquid heat medium 36 returned from the condenser 26. The heat medium 36 sent from the condenser 26 to the inside of the main body 40 of the AQC boiler 16 exchanges heat with the exhaust gas and is preheated, and the steam drum 42 of the AQC boiler 16, the steam drum 34 of the PH boiler 14, and the first flasher 18 Has been sent to.

A part of the heat medium 36 preheated by the AQC boiler 16 is sent to the first flasher 18. The first flasher 18 separates the heat medium 36 into brackish water. The steam generated by the first flasher 18 is supplied to the steam turbine 22, and the remaining heat medium 36 is sent to the second flasher 20. The second flasher 20 separates the heat medium 36 into brackish water. The steam generated by the second flasher 20 is supplied to the steam turbine 22, and the remaining heat medium 36 is returned to the AQC boiler 16.

Steam is sent to the steam turbine 22. The steam turbine 22 is a multi-stage type. High-pressure steam from the PH boiler 14 and the AQC boiler 16 is supplied to the high-pressure stage of the steam turbine 22. The low-pressure stage of the steam turbine 22 is supplied with relatively low-pressure steam from the first flasher 18 and the second flasher 20. Although not shown, the steam turbine 22 includes blades. The blades are rotated by steam.

The flow meter 21 measures the flow rate of steam sent to the steam turbine 22. In this embodiment, the measurement of the flow rate of steam from the PH boiler 14, the measurement of the flow rate of steam from the AQC boiler 16, the measurement of the flow rate of steam from the first flasher 18, and the measurement of the flow rate of steam from the second flasher 20. There are four flowmeters 21 for measurement. The sum of the values measured by these flow meters 21 is the flow rate of steam supplied to the steam turbine 22. In the steam turbine 22, the total is the flow rate of steam flowing from the steam turbine 22 into the condenser 26 (referred to as turbine exhaust flow rate). In other words, these flow meters 21 are flow meters for measuring the turbine exhaust flow rate.

Although not shown, steam turbines with bleed ports may be used. In this case, the turbine exhaust flow rate is a value obtained by subtracting the flow rate of steam discharged from the extraction port from the flow rate of steam sent to the steam turbine.

The rotating shafts of the blades of the steam turbine 22 are connected to the generator 24. The generator 24 generates electricity by rotating the blades. The generator 24 converts the rotational energy of the blades of the steam turbine 22 into electric power.

Steam that has passed through the steam turbine 22 is sent to the condenser 26. The coolant sent from the cooler 28 is circulated in the condenser 26. This vapor is cooled with a coolant and liquefied. The condenser 26 condenses the exhaust gas of the steam turbine 22. This vapor becomes a liquid heat medium 36. When the steam liquefies, the volume suddenly decreases, and the inside of the condenser 26 becomes a state close to vacuum. The liquefied heat medium 36 is pumped out by the condensate pump 45, and further returned to the AQC boiler 16 via the pump 46.

FIG. 2 shows the details of the cooler 28 and controller 30 of FIG. 1 together with the condenser 26 and the steam turbine 22. Although not drawn in FIG. 1, the power generation facility 2 further includes a pressure gauge 48, as shown in FIG.

The cooler 28 cools the steam in the condenser 26. The cooler 28 circulates the coolant 52 between the inside and the outside of the condenser 26. In FIG. 2, arrow B indicates the flow of the coolant 52. A typical coolant 52 is water. As shown in FIG. 2, the cooler 28 includes a heat exchange unit 54, an outer wall portion 56, a sprinkler pipe 58, a fan 60, a motor 62, a water tank 64, a pump 66, an outside air wet bulb thermometer 68, and a coolant thermometer 70. And a water pressure gauge 71. The cooler 28 is a cooling tower.

The heat exchange unit 54 is located inside the condenser 26. The coolant 52 is flowing inside the heat exchange unit 54. The steam exchanges heat with the coolant 52 and is cooled. As a result, the vapor is liquefied. This heat exchange raises the temperature of the coolant 52.

The watering pipe 58 is connected to the output unit 72 of the heat exchange unit 54. The watering pipe 58 is located inside the outer wall portion 56. As shown in FIG. 2, there are three watering pipes 58 in this embodiment. Each watering pipe 58 can sprinkle the coolant 52 toward the water tank 64. A valve 74 is provided between the watering pipes 58 so that it is possible to control from which watering pipe 58 the water is sprinkled.

The fan 60 is located above the watering pipe 58. As shown in FIG. 2, in this embodiment, three fans 60, a first fan 60a, a second fan 60b, and a third fan 60c, are provided. As the fan 60 rotates, air flows into the outer wall portion 56 from between the outer wall portion 56 and the water tank 64. This air rises at the place where the coolant 52 is sprinkled and is discharged to the outside through the fan 60. The rotation of the fan 60 causes an air flow in the place where the coolant 52 is sprinkled. As a result, the coolant 52 is air-cooled. As a result, the temperature of the coolant 52 that has risen in the heat exchange section 54 is lowered.

The motor 62 rotates the fan 60. In this embodiment, three motors 62 are provided corresponding to each fan 60. In each motor 62, start and stop can be controlled by a control signal. In other words, the start and stop of the fan 60 can be controlled by this control signal. In each motor 62, the rotation speed can be changed by a control signal. In other words, the rotation speed of the fan 60 can be changed by this control signal. The motor 62 is usually arranged outside the outer wall portion 56.

The coolant 52 is stored in the water tank 64. The water tank 64 is located below the watering pipe 58. The coolant 52 sprinkled from each watering pipe 58 enters the water tank 64.

The inlet of the pump 66 is connected to the water tank 64, and the outlet is connected to the heat exchange unit 54. The pump 66 sends the coolant 52 in the water tank 64 to the heat exchange unit 54. The pump 66 circulates the coolant 52. As shown in FIG. 2, in this embodiment, two pumps 66, a first pump 66a and a second pump 66b, are provided. In each pump 66, start and stop can be controlled by a control signal. In each pump 66, the rotation speed can be changed by a control signal.

The coolant thermometer 70 measures the temperature of the coolant 52. In this embodiment, there is a first thermometer 70a that measures the temperature of the coolant 52 at the inlet of the condenser 26 and a second thermometer 70b that measures the temperature of the coolant 52 at the outlet of the condenser 26. do. The water pressure gauge 71 measures the water pressure of the coolant 52 at the inlet of the condenser 26. The outside air wet-bulb thermometer 68 measures the wet-bulb temperature outside the cooler 28. These measurement results are sent to the controller 30.

The pressure gauge 48 measures the pressure inside the condenser 26. In other words, the pressure gauge 48 measures the degree of vacuum of the condenser 26. This measurement result is sent to the controller 30.

Reference numeral I in FIG. 2 is an input signal to the controller 30. As shown in FIG. 2, the measurement results of the pressure gauge 48, the coolant thermometer 70, the water pressure gauge 71, and the outside air wet-bulb thermometer 68 are input to the controller 30. Reference numeral C is a control signal from the controller 30. The control signal from the controller 30 is sent to the respective motor 62 and the pump 66, respectively. The controller 30 can control the number of operating fans 60 and the rotation speed of the fans 60 by the control signal. The controller 30 can control the number of operating pumps 66 and the number of rotations of the pumps 66 by the control signal.

The controller 30 can control the cooling capacity of the cooler 28. When increasing the cooling capacity of the cooler 28, the controller 30 increases the number of operating fans 60 or increases the rotation speed of the fans 60. The ability of the fan 60 to air-cool the coolant 52 increases, and the temperature of the coolant 52 decreases. As a result, the cooling capacity of the cooler 28 is increased. When the cooling capacity of the cooler 28 is lowered, the controller 30 reduces the number of operating fans 60 or lowers the rotation speed of the fans 60. The air cooling capacity of the coolant 52 by the fan 60 decreases, and the temperature of the coolant 52 rises. As a result, the cooling capacity of the cooler 28 is reduced.

Further, when the cooling capacity of the cooler 28 is increased, the controller 30 increases the number of operating pumps 66 or increases the rotation speed of the pumps 66. The flow rate of the coolant 52 flowing through the heat exchange unit 54 increases, and the cooling capacity of the cooler 28 increases. When the cooling capacity of the cooler 28 is lowered, the controller 30 reduces the number of operating pumps 66 or lowers the rotation speed of the pumps 66. The flow rate of the coolant 52 flowing through the heat exchange section 54 is reduced, and the cooling capacity of the cooler 28 is reduced.

In this power generation facility 2, the pressure range of the condenser 26 to be set is determined according to the turbine exhaust flow rate. This is a range for efficient power generation while preventing damage to the power generation facility 2. FIG. 3 is an example of a graph showing the pressure range of the condenser 26 to be set according to the turbine exhaust flow rate. The lower limit of this range is determined from the limit value of the wetness of the steam exhausted from the steam turbine 22. The upper limit of this range is determined from the strength of the blades of the steam turbine 22. In this graph, the area indicated by the reference numeral X is the operable area, and the area indicated by the reference numeral Y is the conditional operable area. As shown in FIG. 3, the pressure of the condenser 26 to be set tends to decrease as the turbine exhaust flow rate decreases. The pressure range of the condenser 26 to be set becomes narrower as the turbine exhaust flow rate becomes smaller.

In the power generation facility 2, the controller 30 controls the cooling capacity of the cooler 28 so that the pressure of the condenser 26 falls within the range shown in FIG. 3 according to the turbine exhaust flow rate. FIG. 4-8 is a flowchart showing a method of controlling the cooling capacity by the controller 30. Hereinafter, these will be described in detail.

FIG. 4 shows the overall flow of control by the controller 30. In step S1, the controller 30 determines whether or not the pressure of the condenser 26 is within the range X of the region X of FIG. 3 from the values of the turbine exhaust flow rate and the pressure of the condenser 26. When it is within the range, this step S1 is repeated at predetermined time intervals. That is, the controller 30 constantly monitors the pressure of the condenser 26. When the pressure of the condenser 26 is larger than the upper limit indicated by the region X, the pump capacity improving process of step S2 is performed. As a result, the cooling capacity of the cooler 28 is improved. If the pressure is still higher than the upper limit indicated by the region X in this process, the fan capacity improving process in step S3 is performed. As a result, the cooling capacity of the cooler 28 is further improved. When the pressure of the condenser 26 becomes equal to or less than the upper limit indicated by the region X by the process of step S2 or 3, the process returns to step S1 and the same process is repeated. If it does not fall below the upper limit, an abnormal state is issued, for example, a warning is issued to the equipment manager, and the manager performs necessary processing. For example, if the pressure is within the range of the region Y, the manager stops the equipment 2 at the stage where this state continues for a predetermined time. The manager immediately shuts down the equipment 2 if the pressure is outside the range of region Y.

In the determination of step S1, when the pressure of the condenser 26 is smaller than the lower limit indicated by the region X, the fan capacity reduction process of step S4 is performed. As a result, the cooling capacity of the cooler 28 is reduced. If the pressure is still smaller than the region X in this process, the pump capacity reducing process in step S5 is performed. As a result, the cooling capacity of the cooler 28 is further reduced. When the pressure of the condenser 26 becomes equal to or higher than the lower limit indicated by the region X by the process of step S4 or 5, the process returns to step S1 and the same process is repeated. If it does not exceed the lower limit, an abnormal state is issued, for example, a warning is issued to the equipment manager, and the manager performs necessary processing.

FIG. 5 shows the details of the pump capacity improving process in step S2. In this process, in step S2-1, it is determined whether or not the rotation speed of the pump 66 to be controlled is less than 100% of the maximum rotation speed. Here, the pump 66 to be controlled is, for example, a pump 66 recently controlled by the controller 30. In the embodiment of FIG. 2, when the first pump 66a is operated by the control unit at a rotation speed of 50% of the maximum rotation speed and the second pump 66b is not operating and is stopped, the first pump 66a is controlled. Be the target. When the rotation speed of the pump 66 is less than 100% of the maximum rotation speed, step S2-2 is carried out, and when it is 100%, step S2-4 is carried out.

In step S2-2, the process of increasing the rotation speed of the pump 66 is performed. The rotation speed of the pump 66 is increased by a predetermined value. For example, the controller 30 raises the rotation speed of the first pump 66a from 50% to 75% of the maximum rotation speed.

In step S2-3, it is determined whether or not the pressure of the condenser 26 has become equal to or less than the upper limit value of the region X by the process of step S2-2. This is determined after a certain period of time (for example, 1 hour) in order to wait for the stable state after the processing of step S2-2. When the value becomes equal to or less than the upper limit of the region X, the process of step S2 is terminated and the process returns to step S1. If it is not equal to or less than the upper limit value of the region X, the process returns to step S2-1.

In step S2-4, it is determined whether all the pumps 66 are in operation. When there is a pump 66 that is not in operation, in step S2-5, the controller 30 adds one of them as an object to be operated and controls it. For example, in the previous example, the stopped second pump 66b is added as a pump 66 to be operated. After this addition, the process returns to step S2-1. When all the pumps 66 are already in operation, the control unit determines that the pressure of the condenser 26 cannot be made equal to or lower than the upper limit of the region X by the control of the pumps 66, and ends the step S2. The fan capacity improving process of step S3 is carried out.

FIG. 6 shows the details of the fan capacity improving process in step S3. In this process, in step S3-1, it is determined whether or not the rotation speed of the fan 60 to be controlled is less than 100% of the maximum rotation speed. Here, the fan 60 to be controlled is, for example, a recently operated fan 60. In the embodiment of FIG. 2, the first fan 60a operates at 100% of the maximum rotation speed, and the second fan 60b operated after the first fan 60a operates at 50% of the maximum rotation speed. When the third fan 60c is not operating and is stopped, the second fan 60b is subject to control. When the rotation speed of the fan 60 is less than 100% of the maximum rotation speed, step S3-2 is carried out, and when it is 100%, step S3-4 is carried out.

In step S3-2, the process of increasing the rotation speed of the fan 60 to be controlled is performed. The rotation speed of the fan 60 is increased by a predetermined value. For example, the controller 30 raises the rotation speed of the second fan 60b from 50% to 75% of the maximum rotation speed.

In step S3-3, it is determined whether or not the pressure of the condenser 26 has become equal to or less than the upper limit value of the region X by the process of step S3-2. This is determined after a certain period of time (for example, 1 hour) in order to wait for the stable state after the processing of step S3-2. When the value becomes equal to or less than the upper limit value of the region X, the process of step S3 is terminated and the process returns to step S1. If it is not equal to or less than the upper limit value of the region X, the process returns to step S3-1.

In step S3-4, it is determined whether all the fans 60 are in operation. When there is a fan 60 that is not in operation, in the process of step S3-5, the controller 30 adds one of them as an operation target and controls it. For example, in the previous example, the third fan 60c that is not operating is added as an operating target. After this addition, the process returns to step S3-1. When all the fans 60 are already in operation, the control unit determines that the pressure of the condenser 26 cannot be equal to or lower than the upper limit value of the region X, and ends the process of step S3. As the above-mentioned abnormal state, for example, a warning is issued to the equipment manager, and the manager performs necessary processing.

FIG. 7 shows the details of the fan capacity reduction process in step S4. In this process, in step S4-1, it is determined whether or not the rotation speed of the fan 60 to be controlled is greater than 0% of the maximum rotation speed (whether or not it is stopped). Here, the fan 60 to be controlled is, for example, a recently operated fan 60. In the embodiment of FIG. 2, when the first fan 60a operated first operates at a rotation speed of 100% of the maximum rotation speed, and the second fan 60b operated later operates at a rotation speed of 50%. , The second fan 60b is the target of control. If the rotation speed of the fan 60 is greater than 0% of the maximum rotation speed, step S4-2 is carried out, and if it is 0%, step S4-4 is carried out.

In step S4-2, a process for reducing the rotation speed of the fan 60 is performed. The rotation speed of the fan 60 is reduced by a predetermined value. For example, the controller 30 reduces the rotation speed of the second fan 60b from 50% to 25% of the maximum rotation speed.

In step S4-3, it is determined whether or not the pressure of the condenser 26 has become equal to or higher than the lower limit value of the region X by the process of step S4-2. This is determined after a certain period of time (for example, 1 hour) in order to wait for the stable state after the processing of step S4-2. When the value exceeds the lower limit of the region X, the process of step S4 is terminated and the process returns to step S1. If the value is not equal to or greater than the lower limit of the region X, the process returns to step S4-1.

In step S4-4, it is determined whether or not all the fans 60 are stopped. When there is an unstopped fan 60, one of them is added as a target for reducing the rotation speed in the step S4-5. For example, in the previous example, the first fan 60a, which has been operating at a rotation speed of 100% of the maximum rotation speed, is added as a control target. After this addition, the process returns to step S4-1. When all the fans 60 have already been stopped, the control unit determines that the pressure of the condenser 26 cannot be equal to or higher than the lower limit of the region X by controlling the fans 60, and ends the process of step S4. do. The pump capacity reduction process of step S5 is carried out.

FIG. 8 shows the details of the pump capacity reduction process in step S5. In this process, in step S5-1, it is determined whether or not the rotation speed of the pump 66 to be controlled is greater than 0% of the maximum rotation speed (whether or not it is stopped). Here, the pump 66 to be controlled is, for example, a recently operated pump 66. In the embodiment of FIG. 2, when the first pump 66a, which is operated first, is operated at 100% of the maximum rotation speed, and the second pump 66b, which is operated later, is operated at 50% of the rotation speed. , The second pump 66b is the target of control. If the rotation speed of the pump 66 is greater than 0% of the maximum rotation speed, step S5-2 is carried out, and if it is 0%, step S5-4 is carried out.

In step S5-2, a process for reducing the rotation speed of the pump 66 is performed. The rotation speed of the pump 66 is reduced by a predetermined value. For example, the controller 30 reduces the rotation speed of the second pump 66b from 50% to 25% of the maximum rotation speed.

In step S5-3, it is determined whether or not the pressure of the condenser 26 has become equal to or higher than the lower limit value of the region X by the process of step S5-2. This is determined after a certain period of time (for example, 1 hour) in order to wait for the stable state after the processing of step S5-2. When the value exceeds the lower limit of the region X, the process of step S5 is terminated and the process returns to step S1. If it is not equal to or greater than the lower limit of the region X, the process returns to step S5-1.

In step S5-4, it is determined whether or not all the pumps 66 are stopped. When there is an unstopped pump 66, one of them is added as a rotation speed reduction target in the step S5-5. For example, in the previous example, the first pump 66a, which has been operating at a rotation speed of 100% of the maximum rotation speed, is added as a control target for reducing the rotation speed. After this addition, the process returns to step S5-1. When all the pumps 66 have already been stopped, the control unit determines that the pressure of the condenser 26 cannot be equal to or higher than the lower limit of the region X, and ends the process of step S5. As the above-mentioned abnormal state, for example, a warning is issued to the equipment manager, and the manager performs necessary processing.

In the embodiment described above, the rotation speed of the pump 66 was variable. A pump 66 whose rotation speed is not variable may be used. The pump 66 is in either a stopped state (rotation speed is 0% of the maximum rotation speed) or is in operation (rotation speed is 100% of the maximum rotation speed). In this case, the controller 30 operates the pump 66 that was stopped in step S2-2 (processing of increasing the number of revolutions) in step S2, and in step S5-2 (processing of reducing the number of revolutions) of step S5. The operating pump 66 is stopped.

In the embodiment described above, the rotation speed of the motor 62 for driving the fan 60 was variable. A motor 62 whose rotation speed is not variable may be used. At this time, the fan 60 is in either a stopped state (rotational speed is 0% of the maximum rotational speed) or is in operation (rotational speed is 100% of the maximum rotational speed). In this case, the controller 30 operates the fan 60 which was stopped in the process S3-2 (processing of increasing the rotation speed) of the process S3, and operates the fan 60 in the process S4-2 (processing of reducing the rotation speed) of the process S4. Then, the operating fan 60 is stopped.

In the embodiment described above, the controller 30 executes the change of the rotation speed of the pump 66 and the number of the pumps 66 to be operated, and the change of the rotation speed of the fan 60 and the number of the fans 60 to be operated. Was. The controller 30 informs the driver that the pressure of the condenser 26 is outside the range of region X, and these changes may be made by the driver. In this case, the controller 30 functions as an operation support for controlling the cooling capacity of the cooler 28 so that the pressure of the condenser 26 falls within a predetermined range according to the turbine exhaust flow rate.

In the power generation facility 2, in addition to the cooling capacity control function described above, the controller 30 has a function of determining whether or not the condenser 26 has a failure from the parameters indicating the operating status of the power generation facility 2.
Failure diagnosis by this function is
(C1) The process of defining the relationship between the parameters indicating the operating status and the pressure range of the condenser 26, and (C2) the above parameters measured by the controller 30 during actual operation and the condenser 26. It is performed by carrying out a process of determining the presence or absence of a failure from the pressure.

In the step C1, the power generation facility 2 is commissioned while changing the turbine exhaust flow rate, the temperature of the coolant 52, and the operating number and the number of rotations (flow rate of the coolant 52) of the pump 66, and correspond to the values of these parameters. The pressure range of the condenser 26 is measured. As a result, the pressure range of the condenser 26 is set according to the values of these parameters during normal operation. The pressure range of the condenser 26 may be set by combining the value in the test run and the value obtained in the simulation.

In the step C2, in the actual operation of the power generation facility 2, the controller 30 uses the above-mentioned turbine exhaust flow rate, the temperature of the coolant 52 at the inlet and outlet of the condenser 26 from the condenser thermometer 70, and the pump. From the flow rate of the coolant 52 from the operating status of 66 and the pressure of the condenser 26 from the pressure gauge 48, it is checked whether this pressure is within the range obtained in the step C1. If it is out of this range, the controller 30 warns the driver. For example, when the pressure of the condenser 26 is larger than the range of C1, it is suspected that air flows into the condenser 26 from the outside. The controller 30 warns that the degree of sealing of the condenser 26 may have deteriorated.

The failure determination can also be realized by the control flow shown in FIG. For example, if the pressure of the condenser 26 is larger than the upper limit value shown in FIG. 3 even after the above-mentioned step S3 is performed, it is suspected that air flows into the condenser 26 from the outside. In this case, the controller 30 warns that the degree of sealing of the condenser 26 may have deteriorated.

In the power generation facility 2, the controller 30 further has a function of determining whether or not the cooler 28 has a failure. In the embodiment shown below, the accumulation of dirt on the heat exchange section 54 of the cooler 28 is diagnosed. In this function, the pressure Pc of the condenser 26 measured by the pressure gauge 48, the coolant temperature ti at the inlet of the condenser 26 measured by the coolant thermometer 70, and the cooling at the outlet of the condenser 26. The liquid temperature to, the water pressure pw of the coolant 52 at the inlet of the condenser 26 measured by the water pressure gauge 71, and the flow rate vw of the coolant 52 obtained from the operating status of the pump 66 are used.

In this function, the saturation temperature Tc of the steam in the condenser 26 is calculated from the pressure Pc of the condenser 26. From this, the coolant temperature ti and the coolant temperature to, the logarithmic mean temperature difference ΔT in the condenser 26 is calculated by the following formula.
ΔT = (θ1-θ2) / In (θ1 / θ2)
here,
θ1 = Tc-to, θ2 = Tc-ti
Is.
From this logarithmic mean temperature difference ΔT, the heat exchange amount Q [W] in the condenser 26 is given by the following equation.
Q = K × C × A × ΔT ・ ・ ・ ・ (1)
here,
K: A value obtained by correcting the reference thermal transmission rate of the heat exchange section based on the material, thickness, and coolant temperature. C: Correction coefficient of the thermal transmission rate of the heat exchange section based on the cleanliness of the tube of the cooler 28. A: Heat exchange The heat transfer area of the part. The above value of K is obtained from the preliminary evaluation and the coolant temperature. The value of A above is known. C is a predetermined value (for example, 1) when there is no problem of dirt accumulation in the heat exchange section.

In this function, the enthalpy difference ΔE [kJ / kg] of the coolant 52 between the inlet and the outlet of the condenser 26 can be obtained from the coolant temperature ti, the coolant temperature to, and the water pressure pw of the coolant 52. From this value and the flow rate vw of the coolant 52, the heat exchange amount Q [W] in the condenser 26 is given by the following equation.
Q = vw × ΔE ・ ・ ・ ・ (2)

The heat exchange amount Q of the formula (1) and the heat exchange amount Q of the formula (2) have the same value when there is no problem in the heat exchange unit 54 (for example, when C = 1). When the heat exchange amount Q of the above formula (2) is smaller than the heat exchange amount Q of the above formula (1), it is determined that the cooler 28 is not normal, assuming that the value of the above C is smaller than 1. For example, the controller 30 issues a warning that dirt has accumulated in the pipe of the heat exchange unit 54.

Hereinafter, the effects of the present invention will be described.

It is important to adjust the degree of vacuum (pressure) of the condenser in order to improve the power generation efficiency while suppressing damage to the power generation equipment. The range of this appropriate degree of vacuum depends on the turbine exhaust flow rate. In a power generation facility that uses waste heat, the amount of waste heat that can be used fluctuates depending on the operating conditions of the plant, and therefore the turbine exhaust flow rate also fluctuates.

The power generation facility 2 according to the present invention controls the cooling capacity of the cooler 28 so that the pressure of the condenser 26 falls within a predetermined range according to the turbine exhaust flow rate obtained from the measurement result of the flow meter 21. The controller 30 is provided. The controller 30 controls the cooling capacity so that the pressure of the condenser 26 falls within the region X of FIG. 3 according to the turbine exhaust flow rate. Even if the turbine exhaust flow rate fluctuates, the pressure of the condenser 26 can be put into the region X of FIG. In this power generation facility 2, good power generation efficiency can be achieved while suppressing damage.

In this embodiment, the controller 30 can control the cooling capacity of the cooler 28 by controlling the number and the number of rotations of the pump 66 that circulates the coolant 52. Further, the cooling capacity of the cooler 28 can also be controlled by controlling the number of fans 60 and the number of rotations for cooling the coolant 52. These make it possible to easily control the cooling capacity in a wide range. Even if the surrounding conditions of the power generation facility 2 fluctuate, such as fluctuations in the operating status of the plant and fluctuations in the environmental temperature, the pressure of the condenser 26 can be easily put into the region X in FIG. In this power generation facility 2, good power generation efficiency can be achieved while suppressing damage.

In this embodiment, the controller 30 automatically adjusts the cooling capacity of the cooler 28 so that the pressure of the condenser 26 falls within a predetermined range according to the turbine exhaust flow rate obtained from the measurement result of the flow meter 21. Control. Compared to the control by the driver, the pressure of the condenser 26 can be efficiently put into the region X of FIG. 3 regardless of the skill level of the driver. In this power generation facility 2, good power generation efficiency can be achieved while suppressing damage.

In this embodiment, the controller 30 has a function of determining whether or not the condenser 26 has a failure from the parameters indicating the operating status of the power generation facility 2. Deterioration of the degree of sealing of the condenser 26 can be detected early from the turbine exhaust flow rate, the temperature of the coolant 52, the operating number and the number of rotations of the pump 66, and the pressure of the condenser 26. Maintenance of this power generation facility 2 is easy.

In this embodiment, the controller 30 has a function of determining whether or not the cooler 28 has a failure from the parameters indicating the operating status of the power generation facility 2. The pressure of the condenser 26 measured by the pressure gauge 48, the coolant temperature at the inlet and outlet of the condenser 26 measured by the coolant thermometer 70, and the inlet of the condenser 26 measured by the water pressure gauge 71. From the water pressure of the coolant 52 and the flow rate of the coolant 52 obtained from the operating condition of the pump 66, damage to the pipe circulating the coolant 52, accumulation of dirt, and the like can be detected at an early stage. Maintenance of this power generation facility 2 is easy.

In the embodiment described above, this power generation facility utilizes the waste heat of the cement plant. This power generation facility is not limited to cement plants. This power generation facility can be applied in various plants where waste heat is generated.

As described above, in this power generation facility, even if the turbine exhaust flow rate fluctuates, good power generation efficiency can be achieved while suppressing damage. From this, the superiority of the present invention is clear.

The power generation equipment described above can be applied to the utilization of waste heat of various plants.

2 ... Power generation equipment 4 ... Cement firing equipment 14 ... PH boiler 16 ... AQC boiler 21 ... Flow meter 22 ... Steam turbine 24 ... Generator 26 ... Condenser 28 ... Cooler 30 ... Controller 36 ... Heat medium 48 ... Pressure gauge 52 ... Coolant 60 ... Fan 62 ... Motor 64 ... Water tank 66 ... Pump 70 ・ ・ ・ Coolant thermometer 71 ・ ・ ・ Water pressure gauge

Claims (6)

A boiler that generates steam, a steam turbine that is operated by this steam, a condenser that condenses the exhaust of this steam turbine, a cooler that sends coolant to this condenser, and measures the pressure inside this condenser. A pressure gauge, a flowmeter for measuring the flow rate of the exhaust to the condenser, and the cooling capacity of the cooler are controlled so that the pressure of the condenser falls within a predetermined range according to the flow rate of the exhaust. Power generation equipment equipped with a controller for The power generation facility according to claim 1, wherein the cooler includes at least one fan for cooling the coolant and at least one pump for circulating the coolant. The power generation facility according to claim 2, wherein the controller controls the cooling capacity by controlling the number of the fans to be operated or the rotation speed of the fans. The power generation facility according to claim 2 or 3, wherein the controller controls the cooling capacity by controlling the number of the pumps to be operated or the rotation speed of the pumps. Further provided with a coolant thermometer for measuring the temperature of the coolant at the inlet and outlet of the condenser.
Whether or not the condenser has failed based on the temperature of the coolant, the pressure of the condenser, the flow rate of the exhaust to the condenser, and the flow rate of the coolant obtained from the operating status of the pump. The power generation facility according to any one of claims 2 to 4, wherein the power generation facility can be determined. Further equipped with a coolant thermometer for measuring the temperature of the coolant at the inlet and outlet of the condenser, and a water pressure gauge for measuring the pressure of the coolant at the inlet of the condenser.
The controller can determine the presence or absence of failure of the cooler from the temperature of these coolants, the pressure of the coolant, the pressure of the condenser, and the flow rate of the coolant obtained from the operating status of the pump. , The power generation facility according to any one of claims 2 to 5.

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