JP5882869B2 - Power plant operation method - Google Patents

Description

  The present invention relates to a power plant such as a thermal power plant, and more particularly to a method of operating a power plant including a condensate demineralizer.

  In a thermal power plant (or nuclear power plant), steam is generated by heating water in a boiler (or nuclear reactor), the steam turbine is driven by this steam, and the steam discharged from the steam turbine is collected by a condenser. The condensed water is supplied to a boiler (or a nuclear reactor) through a condensate system (water supply system). During normal operation, the water flow rate of the condensate system is stable, and the concentration of the clad in the water (specifically, a suspended substance containing iron oxide as a main component) is, for example, about 20 to 50 μg / L. Stable at a relatively low level. For this reason, the condensate system does not have a filtration device mainly for removing the clad, and it is a condensate desalination device mainly for desalination treatment (specifically, a desalination filled with an ion exchange resin). Only a salt tower) may be installed. Thereby, it is possible to purify the water while reducing the cost.

  However, when the power plant is started up (at the time of initial startup or restart), a large amount of clad accumulated in the system flows due to a sudden change in the water flow rate, and the clad concentration in the water is several thousand μg / L may be reached. When the condensate demineralizer is passed with the clad concentration being high, the ion exchange resin is contaminated by corrosion products (oxides and hydroxides of heavy metal elements such as iron) in the clad, and the ion exchange resin. There is a possibility that the performance of

  Here, when the power plant is started, it is known to perform a clean-up operation of the condensate system (see, for example, Patent Document 1). At this time, in order to prevent the above-described contamination of the ion exchange resin, for example, a method of restricting water flow to the condensate demineralizer according to the clad concentration is adopted. Explaining in detail, water is sampled from the upstream side of the condensate demineralizer, the clad concentration is measured, and the clad concentration is a specified value which is a water flow condition of the ion exchange resin (specifically, for example, about 500 μg / L). The water flow to the condensate demineralizer is restricted until it becomes less, and drained (blow) out of the system from the upstream side of the condensate demineralizer. Thereafter, if the clad concentration in the water on the upstream side of the condensate demineralizer becomes less than the specified value, the condensate demineralizer is passed through. Then, water is sampled from the downstream side of the condensate demineralizer, the clad concentration is measured, and the water supply to the boiler is limited until the clad concentration is less than a predetermined value, and the downstream side of the condensate demineralizer Drain from the condenser to the condenser. In this way, the condensate system is cleaned up in stages.

JP 09-79509 A

  In the above prior art, until the clad concentration in water on the upstream side of the condensate demineralizer is less than the specified value which is the condition of the ion exchange resin, the water flow to the condensate demineralizer is limited, Waste water is discharged from the upstream side of the condensate demineralizer. In other words, the condensate system cleanup operation cannot proceed to the next stage until the clad concentration in the water on the upstream side of the condensate demineralizer becomes less than the specified value. Therefore, the clean-up time of the condensate system was promoted, and consequently the start-up time of the power plant was promoted.

  The objective of this invention is providing the operating method of a power plant which can aim at shortening of the starting time of a power plant.

  In order to achieve the above object, the present invention provides a steam generator, a steam turbine driven by steam generated by the steam generator, a condenser that condenses steam discharged from the steam turbine, In an operation method of a power plant comprising a condensate system for supplying water condensed in a condenser to the steam generator, and a demineralization tower provided in the condensate system, at the start of the power plant, A first procedure for passing water in a state in which the demineralization tower is filled with a cladding-removing packing; a second procedure for measuring a clad concentration in water upstream of the demineralization tower; and an upstream side of the demineralization tower When the clad concentration in water in the water becomes less than a specified value, the demineralization tower has a third procedure of passing water in a state of being filled with an ion exchange resin.

  In the present invention, first, the desalting tower is filled with the cladding removal filler, so that the water passage conditions of the desalting tower can be relaxed compared to, for example, filling with an ion exchange resin. Thereby, at the time of starting of a power generation plant, even if the clad density | concentration in the water in the upstream of a desalting tower is more than a regulation value (water passing condition of an ion exchange resin), it can pass a desalting tower. Therefore, for example, the cleanup time of the condensate system can be shortened compared with the case where the water flow to the desalting tower is limited. Further, since water is passed in a state where the desalting tower is filled with the cladding removing packing, for example, when the desalting tower is not filled with the cladding removing packing, or when the desalting tower is bypassed. Rather, the reduction of the clad concentration in water in the condensate system can be promoted. Therefore, from this point of view, it is possible to shorten the cleanup time of the condensate system. As a result, the startup time of the power plant can be shortened.

  ADVANTAGE OF THE INVENTION According to this invention, shortening of the starting time of a power plant can be aimed at.

It is the schematic showing the structure of the thermal power plant in one Embodiment of this invention. It is the schematic showing the structure of the condensate demineralization apparatus in one Embodiment of this invention with related facilities, and shows the operation state during normal operation. It is the schematic showing the structure of the condensate demineralization apparatus in one Embodiment of this invention with related equipment, and shows the operation state in the case of reproducing | regenerating an ion exchange resin. It is the schematic showing the structure of the condensate demineralization apparatus in one Embodiment of this invention with related equipment, and shows the operation state in the case of reproducing | regenerating an ion exchange resin. It is a flowchart showing the operating method of the power plant in one Embodiment of this invention. It is the schematic showing the structure of the condensate demineralization apparatus in one Embodiment of this invention with related facilities, and shows the operation state at the time of starting of a power plant. It is the schematic showing the structure of the condensate demineralization apparatus in one Embodiment of this invention with related facilities, and shows the operation state at the time of starting of a power plant. It is a figure showing the time-dependent change of the cladding density | concentration at the time of starting of the power plant in one Embodiment of this invention. It is a flowchart showing the operating method of the power plant in the modification of this invention.

  Hereinafter, a case where an embodiment of the present invention is applied to a thermal power plant will be described as an example with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of a thermal power plant in the present embodiment. 2 to 4 are schematic views showing the configuration of the condensate demineralization apparatus according to this embodiment together with related equipment, FIG. 2 shows an operating state during normal operation, and FIGS. 3 and 4 are ion exchange resins. The operation state when playing back is shown. In addition, the black valve in the figure indicates a closed state, and the white valve in the figure indicates a closed state.

  As shown in FIG. 1, the thermal power plant includes a boiler 1, a high pressure steam turbine 2, an intermediate pressure steam turbine 3, a low pressure steam turbine 4, a generator 5, and a condenser 6. The rotary shafts of the steam turbines 2, 3, 4 and the generator 5 are connected to each other. The steam generated in the boiler 1 flows in the order of, for example, a high-pressure steam turbine 2, an intermediate-pressure steam turbine 3, and a low-pressure steam turbine 4, and drives the steam turbines 2, 3, and 4. That is, the steam turbines 2, 3, and 4 convert fluid energy into mechanical energy. The generator 5 converts mechanical energy generated by the steam turbines 2, 3, and 4 into electric energy (that is, generates electricity).

  The condenser 6 cools and condenses the steam discharged from the low-pressure steam turbine 4. The water condensed in the condenser 6 is supplied to the boiler 1 via a condensate system (water supply system) 7. In the condensate system 7, a condensate pump 8, a condensate demineralizer 9, a condensate booster pump 10, a low-pressure feed water heater 11, a deaerator 12, a feed water pump 13, and a high-pressure feed water are arranged in the order along the flow direction. A heater 14 is provided.

  The condensate pump 8 sends the water from the condenser 6 to the condensate demineralizer 9. As shown in FIG. 2 and the like, the condensate demineralizer 9 includes a plurality of demineralization towers 15A (only one is representatively shown in the figure) and a single demineralization tower 15B as a backup. . These desalting towers 15A and 15B are connected by piping between the condensate pump 8 and the condensate booster pump 10 so as to be parallel to each other. During normal operation of the power plant, for example, as shown in FIG. 2, a plurality of desalting towers 15A are filled with ion exchange resin A (specifically, a mixture of cation resin A1 and anion resin A2). The inlet valve 16A and the plurality of outlet valves 17A are opened, and water is passed through the plurality of desalting towers 15A. Thereby, the purification process of the water by the ion exchange resin A is performed (specifically, mainly the desalting process, but also the cladding removal process).

  The water purified by the condensate demineralizer 9 is pressurized by the condensate booster pump 10 and heated by the low-pressure feed water heater 11. The deaerator 12 heats the water from the low-pressure feed water heater 11 and degass it. The water deaerated by the deaerator 12 is pressurized by the feed water pump 13 and heated by the high pressure feed water heater 14.

  As shown in FIG. 2 and the like, pipes are connected between the desalting towers 15A and 15B and the cation regeneration tower 18 so that the ion exchange resin A (or a cladding removing packing B described later) can be transferred. . The cation regeneration tower 18 can back-wash the ion exchange resin A taken out from the desalting tower 15A or 15B, and can be separated into a cation resin A1 and an anion resin A2 by a difference in specific gravity. In addition, a pipe is connected between the cation regeneration tower 18 and the anion regeneration tower 19 so that the anion resin A2 can be transferred.

  Next, an operation procedure for regenerating the used ion exchange resin A will be described. For example, when the ion exchange resin A in any one of the plurality of desalting towers 15A is regenerated, first, the water passing through one desalting tower 15A is passed through the spare desalting tower 15B. Switch to water. That is, as shown in FIG. 3, the inlet valve 16B and the outlet valve 17B are opened and water is passed through the desalting tower 15B, and then one set of the inlet valve 16A and the outlet valve 17A is closed and one desalting tower 15A is closed. Stop water flow. Then, the corresponding resin outlet valve 20A is opened, and the ion exchange resin A is transferred from the desalting tower 15A in a water flow stop state to the cation regeneration tower 18. Then, the washing valve 21 is opened, and water and air are supplied into the cation regeneration tower 18 to wash (backwash) the ion exchange resin A. Thereafter, as shown in FIG. 3, the cleaning valve 21 is closed, and the resin is separated into the cation resin A1 and the anion resin A2 by the specific gravity difference. Then, the anion inlet valve 22 is opened, and the anion exchange resin A2 is transferred from the cation regeneration tower 18 to the anion regeneration tower 19. Then, as shown in FIG. 4, the cation regeneration valve 23 is opened, and a regenerant (for example, sulfuric acid) is supplied into the cation regeneration tower 18 via the distributor 24 to regenerate the cation exchange resin A1. Further, the anion regeneration valve 25 is opened, and a regenerant (for example, caustic soda) is supplied into the anion regeneration tower 19 through the distributor 26 to regenerate the anion exchange resin A2. Thereafter, the anion outlet valve 27 is opened, and the regenerated anion exchange resin A2 is transferred from the anion regeneration tower 19 to the cation regeneration tower 18. Then, the cleaning valve 21 is opened and water and air are supplied into the cation regeneration tower 18 to clean and mix the cation exchange resin A1 and the anion exchange resin A2. Thereafter, the cation outlet valve 28, the switching valve 29, and the corresponding resin inlet valve 30A are opened, and the regenerated ion exchange resin A is returned from the cation regeneration tower 18 to the desalting tower 15A.

  Here, as one of the features of the present embodiment, the cladding removal filler B (specifically, for example, an inert resin or an ion exchange resin whose performance is lower or deteriorated than that of a regular ion exchange resin A) is stored. The storage tanks 31 </ b> A and 31 </ b> B are connected to the desalting towers 15 </ b> A and 15 </ b> B and the cation regeneration tower 18 by piping. The plurality of storage tanks 31A correspond to the plurality of desalting towers 15A, respectively, and the ion exchange resin A and the cladding removal packing B can be exchanged with the desalting towers 15A. Similarly, the storage tank 31B corresponds to the desalting tower 15B, and the ion exchange resin A and the cladding removing packing B can be exchanged with the desalting tower 15B.

  And as the biggest characteristic of this embodiment, at the time of starting of a power generation plant, first, water is passed in a state where a plurality of desalting towers 15A are filled with a cladding removal packing B. The operation method of such a power plant is demonstrated using FIGS. FIG. 5 is a flowchart showing the operation method of the power plant in the present embodiment.

  In FIG. 5, first, in step 100, the power plant is started. At this time, as shown in FIG. 6, the plurality of desalting towers 15A are pre-filled with the cladding removal packing B, and the plurality of storage tanks 31A store the ion exchange resin A. The spare desalting tower 15B is pre-filled with the ion exchange resin A, and the clad removal filler B is stored in the storage tank 31B. In step 110, the plurality of inlet valves 16A and the outlet valve 16B are opened, and the plurality of demineralization towers 15A are passed through.

  Then, it progresses to step 120, water is sampled in the sampling point (water quality monitoring point) 32A or 32B (refer FIG. 1 mentioned above) in the upstream of the condensate demineralizer 9 in the condensate system 7, and clad density | concentration in water Etc. are measured. And it progresses to step 130 and it is determined whether a clad density | concentration is less than a regulation value (specifically, it is the water flow conditions of the ion exchange resin A, for example, about 500 microgram / L). For example, when the cladding concentration is equal to or higher than a specified value, the determination in step 130 is not satisfied, and the procedure returns to the above-described step 120 and the same procedure as described above is repeated. That is, for example, after elapse of a predetermined time, water is resampled at the sampling point 31A or 31B, and the clad concentration in the water is measured. For example, if the cladding concentration is less than the specified value, the determination at step 130 is satisfied, and the routine proceeds to step 140.

  In step 140, the ion exchange resin A is filled into a plurality of desalting towers and water is passed therethrough.

  More specifically, first, the water passing through one desalting tower 15A filled with the cladding removal packing B is switched to the water passing through the spare desalting tower 15B filled with the ion exchange resin A. That is, the inlet valve 16B and the outlet valve 17B are opened and water is passed through the desalting tower 15B, and then one set of the inlet valve 16A and outlet valve 17A is closed to stop water passing through the single desalting tower 15A. Then, the corresponding resin outlet valve 20 </ b> A is opened, and the clad removal packing B is transferred from the desalting tower 15 </ b> A in a water flow stop state to the cation regeneration tower 18. Then, as shown in FIG. 7, the cleaning valve 21 is opened, and water and air are supplied to the cation regeneration tower 18 to clean (backwash) the clad removal filler B. On the other hand, one storage outlet valve 33A, the switching valve 34, and the corresponding resin inlet valve 30A are opened, and the ion exchange resin A is transferred from one storage tank 31A to the desalting tower 15A. Thereafter, the cation outlet valve 28 and the storage inlet valve 35A are opened, and the cleaned clad removal packing B is transferred from the cation regeneration tower 18 to the storage tank 31A.

  Thereafter, the water passing through one desalting tower 15A filled with the cladding removing packing B is sequentially switched to the water passing through the desalting tower 15A filled with the ion exchange resin A by the same procedure. Further, the clad removal packing B sequentially taken out from the desalting tower 15A is washed by the cation regeneration tower 18 and stored in the storage tank 31A.

  Then, when the power plant is stopped in step 150, the process proceeds to step 160, where the ion exchange resin A is sequentially taken out from the desalting tower 15A, and the desalting tower 15A is sequentially filled with the cladding removal filler B. That is, it returns to the state shown in FIG. 6 in preparation for restart of a power plant. Thereafter, when the power plant is restarted in Step 100, the process proceeds to Step 110, where the plurality of inlet valves 16A and the outlet valves 16B are opened, and the plurality of desalting towers 15A are passed through.

  As described above, in the present embodiment, first, since a plurality of desalting towers 15A are filled with the clad removal packing B, for example, compared with the case where the ion exchange resin A is filled, the water passage conditions of the desalting tower 15A Can be relaxed. Thereby, at the time of starting of a power plant, even if the clad density | concentration in the water in the upstream of the desalination condensing apparatus 9 is more than a regulation value (water-flow conditions of the ion-exchange resin A), water is passed through the desalting tower 15A. be able to. Therefore, for example, when restricting the flow of water to the desalting tower 15A (specifically, when draining out of the system from the blow point 36 on the upstream side of the condensate demineralizer 9 (see FIG. 1 described above)). The cleanup time of the condensate system 7 can be shortened. Further, since water is passed through the desalting tower 15A with the cladding removal packing B, for example, water is passed through the desalting tower 15A without being filled with the cladding removal packing B, or the desalting tower 15A is installed. The reduction of the clad concentration in water in the condensate system 7 can be promoted more than when bypassing (see FIG. 8). Therefore, also from this point of view, the cleanup time of the condensate system 7 can be shortened. As a result, the startup time of the power plant can be shortened.

  In the present embodiment, the cladding removing filler B uses an inert resin or an ion exchange resin whose performance is lower or deteriorated than that of the regular ion exchange resin A. That is, the thing similar to the ion exchange resin A is used. Thereby, the regeneration towers 18 and 19 and the piping for the ion exchange resin A can be used.

  In the above-described embodiment, the clad removal packing B after use is transferred to the regeneration tower 18 for cleaning, and the cleaned clad removal packing B is stored in the storage tanks 31A and 31B, thereby generating a power plant. The case of reusing at the time of restarting has been described as an example, but is not limited thereto. That is, for example, as in the modification shown in FIG. 9, the clad removal filler B after use may be taken out of the system and discarded. Even in such a modification, the same effect as described above can be obtained.

DESCRIPTION OF SYMBOLS 1 Steam generator 2 High pressure steam turbine 3 Medium pressure steam turbine 4 Low pressure steam turbine 6 Condenser 7 Condensation system 15A, 15B Desalination tower A Ion exchange resin B Packing for clad removal

Claims (4)

A steam generator; a steam turbine driven by steam generated by the steam generator; a condenser for condensing steam discharged from the steam turbine; and steam generated from the water condensed by the condenser In a method for operating a power plant comprising a condensate system for supplying water to a condenser, and a desalting tower provided in the condensate system,
A first procedure for passing water in a state in which the desalting tower is filled with a packing for removing a clad when starting the power plant;
A second procedure for measuring the clad concentration in water upstream of the desalting tower;
Operation of a power plant characterized by having a third procedure of passing water in a state where the ion-exchange resin is filled in the demineralizer when the clad concentration in water on the upstream side of the demineralizer becomes less than a specified value. Method. In the operating method of the power plant of Claim 1,
A fourth procedure for cleaning the clad removal packing removed from the desalting tower;
And a fifth procedure for passing water in a state in which the desalting tower is filled with the packing for removing the clad after washing when the power plant is restarted. In the operating method of the power plant of Claim 1,
A method for operating a power plant, comprising a fourth procedure of discarding the cladding removal packing taken out from the desalting tower. In the operating method of the power plant of any one of Claims 1-3,
The method for operating a power plant, wherein the clad removal filler is an inert resin or an ion exchange resin having a performance lower than that of the ion exchange resin or deteriorated.

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