JPH01218611A - Apparatus for purifying feed water - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to power plants such as thermal power plants or nuclear power plants, and particularly relates to insoluble impurities (crud) in high-temperature water supply. This invention relates to a purification device incorporating a ceramic filter for removing.

(Conventional technology) In general, in power plants such as thermal power plants and nuclear power plants, the purpose is to prevent impurities from entering and accumulating in the boiler, which is the heat source, or the nuclear reactor, and to maintain water quality at a good level. In addition, extremely strict water quality control is carried out. For this reason, for example, in a thermal power plant, as shown in Figure 8, a condensate demineralizer 10 is installed after the condenser 1, and some of the insoluble solids including ionic components in the condensate are removed. is removed and the quality of condensate is maintained. Also,
Particularly when the plant is stopped, corrosion of piping progresses, so before starting the plant, the Fe and 041Fe generated during the stoppage must be removed.
An operation is performed to remove corrosion products such as 2o3, and this is called cleanup. On the other hand, in nuclear power generation plan 1~, corrosion products (
We are suppressing the occurrence of crud (crud) and removing it.

For example, as shown in FIG. 9, it has been conventional to purify condensate by installing a mixed-bed ion exchange demineralization tower 110 in a condensate line 102 connecting a condenser 101 and a nuclear reactor 100, as in a thermal power plant. Recently, a condensate filtration device 109 has been installed upstream of the conventional ion exchange demineralization tower 110 to more completely separate and remove suspended matter present in the condensate. ing.

This condensate filtration device 109 uses a pre-coated filter such as powdered ion exchange resin (Japanese Patent Publication No. 5
7-35438) is generally used. Furthermore, those that use flat membrane filters such as filter paper or filter cloth membrane filters, or those that use sintered metal,
Research is also underway on methods that use electromagnetic filters. Recently, hollow membrane filter type filtration devices using porous polymeric materials have been put into practical use, and higher performance has been achieved.

Now, I will explain in detail the technology of thermal power plants and atomic couplants.

First, the configuration of a thermal power plant will be explained with reference to FIG.

FIG. 8 is a diagram showing a schematic configuration of a thermal power plant, and neutral number 1 in FIG. 1 is a condenser. A pipe 2 is connected to the condenser 1, and the pipe 2 is connected to a high pressure turbine 3.

A pipe 4 is connected to the high pressure turbine 3, and an intermediate pressure turbine 5 is connected to the pipe 4. A pipe 7 is disposed between the intermediate pressure turbine 5 and the low pressure turbine 6 installed adjacent to the condenser 1. That is, the condensate condensed and liquefied in the condenser 1 is purified and then transferred as feed water to the heating section, where it is heated and turned into steam.

This steam is first supplied to the high pressure turbine 3 to do work, and then transferred to the intermediate pressure turbine 5 to do work. It is further supplied to the low pressure turbine 6 to perform work and then returned to the condenser 1.

The same cycle is repeated thereafter.

To explain in detail below, from the condenser 1 side, the piping 2 includes a condensate pump 8, a demineralizer 1o, a grand steam condenser 11,
and a condensate boost pump 12 are sequentially inserted. A condensate recirculation pipe 13 is branched from the secondary side pipe 2 of the condensate boost pump 12, and this condensate recirculation pipe 13 is connected to the condenser 1. Low-pressure feed water heaters 14, 15 and 16 are successively inserted into the piping 2 on the secondary side of the branch point of the condensate recirculation piping 13, and a deaerator 17 is further inserted therein. A low-pressure cleanup circulation pipe 18 is branched from the deaerator 17 and connected to the condensate recirculation pipe 13 . A boiler feed water pump 19 is interposed on the secondary side of the deaerator 17, and high pressure feed water heaters 20, 21 and 22 are further interposed in sequence. A high-pressure cleanup circulation pipe 23 is branched from the secondary side pipe 2 of the high-pressure feedwater heater 22 and connected to the low-pressure cleanup circulation pipe 18 . The piping 2 on the secondary side of the branch point of the high-pressure cleanup circulation piping 23 includes a carbon saver 24, a furnace 25, and heaters 26a, 26b.
are inserted sequentially. A boiler cleanup circulation pipe 27 branches off from the furnace 25 and is connected to the high pressure cleanup circulation pipe 23 . Further, a reheater 28 is inserted in the pipe 4. Further, a condensate pump outlet blow pipe 29 is branch-connected to the secondary side pipe 2 of the condensate pump 8, and similarly the low pressure cleanup circulation pipe 18 and the high pressure cleanup circulation pipe 23 are connected to the condensate pump outlet blow pipe 29.
A low-pressure cleanup blow piping 30 and a high-pressure cleanup blow piping 31 are also branched and connected to each other. Further, a boiler cleanup pipe 32 is branched and connected to the boiler cleanup circulation pipe 27 as well. Further, a generator 33 is connected to the low pressure turbine 6,
Further, a make-up water pipe 34 and a condenser blow pipe 35 are connected to the condenser 1, respectively.

According to the above configuration, first, during normal operation of the plant, the condensate demineralizer 10 removes ionic components (Fe) contained in the condensate.
3+, Na", CQ-, etc.). At the same time, insoluble solids such as corrosion products are also partially removed to purify condensate.

On the other hand, during startup, there is a large amount of corrosion products in the pipes, and the water quality is considerably worse than during normal operation.

In particular, in the demineralizer 10, if the water quality on the inlet side is poor, the water quality on the outlet side will also deteriorate, so the water quality on the inlet side is controlled by a blow operation to a certain level (for example, the iron concentration is 300 ppb or less).
The following cleanup operations have been performed: This cleanup operation will be explained in detail below. First, fill condenser 1 with water. Next, the water is blown through the condenser blow piping 35 until the water quality at one end of the blower becomes 300 ppb or less. Next, a recirculation operation is performed using the demineralizer 10, the bypass flow path of the grand steam condenser 11 (each device is equipped with a bypass flow path), the condensate pump 8, and the condensate recirculation piping 13. During this recirculation operation, blowing is simultaneously performed from the blow piping 29, and continues until the water quality at one end of the blower drops below a certain level. Next, the pre-filter 9 and the demineralization tower 10 are placed in the collection state, and the condensate is circulated to perform cleanup until the water reaches a predetermined quality.

Next, perform a low pressure cleanup. In this case as well, first blowing is performed via the low-pressure cleanup blow piping 30, and after confirming that the water quality at one end of the blower has become 300 pPb or less, circulation operation is performed via the low-pressure cleanup circulation piping 18. Then, once the water quality is good, we move on to high-pressure cleanup.

In the case of high-pressure cleanup, blowing is first performed via the high-pressure cleanup blow piping 31 as well.

After confirming that the water quality at one end of the blower is 300 ppb or less, circulation operation via the high-pressure blow circulation piping 23 is performed. Next, for boiler cold cleanup, blowing is first performed via the boiler cold cleanup blow piping 32. After confirming that the water quality at one end of the blower is 300 PPb or less, circulation operation via the boiler cleanup circulation piping 27 is performed. Next, perform boiler hot cleanup operation. When the water quality on the secondary side of the condensate pump 8 exceeds 300 PPb, it is blown from the condensate pump outlet blow piping 29, and the water quality at one end of the blower is aoo.
This will continue until it is below ppb.

As described above, the lean-up operation was performed to remove corrosion products generated while the plant was stopped, and then the plant was started up.

The above configuration has the following problems.

(1) First, since the desalination device 10 described above is located after the condenser 1, it can only remove corrosion products generated from the low-pressure turbine 6, condenser 1, and condensate pump 8 during normal operation. Corrosion products generated from the feed water heaters 14, 15, 16, 20, 21° 22, condensate boost pump 12, boiler feed water pump 19, deaerator 17, etc. enter the economizer 24 and furnace 25, and are scaled. It gradually adheres as Therefore, there was a problem in that the plant thermal efficiency was reduced.

■Next, a large amount of pure water is consumed as blow water by performing a blow operation in the clean-up operation at the time of plant start-up. The amount is enormous, and approximately several thousand M of pure water is consumed each time the plant is started, especially if the water quality of the plant is poor. Pure water is replenished into the condenser 1 from a pure water tank (not shown) via the make-up water piping 34, but it is also expected that the pure water tank will become empty and, as a result, the start-up of the plant will be delayed.

■ In addition, the clean-up operation described above is performed every time the plant is started, and the operation is extremely complicated, not only because of the amount of pure water consumed, but also because it takes a long time to start the plant. There was a problem in improving the operating rate.

■ Furthermore, when using pure water, it is necessary to inject certain chemicals (chemicals such as ammonia and hydrazine), so from the perspective of cost reduction, consuming large amounts of pure water is problematic. there were.

The above is the conventional technology for thermal power plants.

Next, referring to FIG. 9, the configuration of a nuclear power plant will be explained using a boiling water type (BWR) as an example. Nuclear power plants have almost the same configuration as thermal power plants, but they differ in the following points.

ω There is no economizer 24, furnace 25, heaters 26a, b,
Instead, there is a nuclear reactor 100 as a heat source.

■ The reheater 28, its return line piping 4, and the intermediate pressure turbine do not exist, and the steam leaving the nuclear reactor 100 rotates the high pressure turbine 103, then the moisture is removed by the moisture separator 136, and the steam is sent to the low pressure turbine. Turn 106.

(3) There is no deaerator 17.

0) Water supply and condensate cleanup blow piping 29°30
．． 31, 32.35 does not exist.

■ In recent plants, there is a condensate filtration device 109.

According to the above configuration, during normal operation, insoluble solids and ionic components are removed by the condensate filter 9' and the demineralizer 110.

On the other hand, at startup, unlike thermal power plants, it is a radioactive fluid and cannot be cleaned up by blowing. Therefore, follow the steps below. First, the water in the condenser is circulated using the piping 113, and purified by the condensate filter 109 and the demineralizer 110.

Next, use the pipes 118 and 123 in sequence to heat the water supply 11.
Purify the inside of 4-122.

The above configuration has the following problems.

■ Similar to the thermal power plant I-, during normal operation, corrosion products generated from the feedwater adders 1]4 to [22], the feedwater pump]19, etc. are not removed and accumulate in the reactor 100. Scale adheres. When this corrosion product is irradiated with neutrons, some induced radioactivity is generated due to the following nuclear reactions, which can lead to increased radiation exposure for workers during periodic inspections, etc.

(Example) “Go(n+”I)”Co, (half-life 5
．． 26) ■ Clean-up operation requires extremely long circulation operation because blowing is not performed.

Currently, approximately one to two weeks are spent on purification operations, which is a factor in lowering the operating rate.

(Problems to be Solved by the Invention) In this conventional configuration, during normal operation, corrosion occurs in the boiler of a thermal power plant and in the reactor of an atomic power plant. There was a problem that products accumulated, leading to deterioration of water quality, a decrease in thermal efficiency for Plan 1, and an increase in radiation exposure for atomic couplants.

Furthermore, upon start-up, the cleanup time of the plant becomes long, leading to a decrease in the operating rate. Especially in the case of nuclear couplers, the output per plant is 70
Since it is a large amount of 1,300,000 to 1,300,000 KIN, the benefits of improving the labor rate are significant.

Furthermore, in the case of a thermal power plant, in order to operate the atomic power converter 1 at a constant output (base load), it is necessary to follow changes in the electric power load and promptly control the output. Therefore, the so-called DSS (Dail, yStart & 5t) operates only during the day and stops at night.
OP) operation, and shortening the cleanup time is an extremely important issue from the perspective of stable power supply.

The present invention was developed based on the above points, and its purpose is to make it possible to remove corrosion products in water supply, thereby improving plant thermal efficiency or reducing radiation exposure, as well as improving cleanup. The purpose of the present invention is to provide a water supply purification device that shortens the time and improves the plan and operating rate.

[Structure of the invention]

(Means for solving the problem) That is, the feed water purification device according to the present invention condenses and
The liquefied condensate is purified by a condensate desalination device, heated through multiple feed water heat exchangers or deaerators, and then transferred to a heat source device, which generates steam and supplies it to a turbine device. In a feed water purification device for a power generation plant, the steam that has done work in the turbine device is collected in the condenser and condensed and liquefied again. This water purification device is characterized in that it has a ceramic filtration device installed between the two, and this ceramic filtration device has a large number of filters made of permeable ceramic arranged inside.

(Function) In other words, a ceramic filtration device is used as a water supply purification device. By adjusting the pore size of the surface micropores of the ceramic filter, this ceramic filter removes insoluble solids with a predetermined particle size or more, regardless of the quality of the water on the primary side.
0% removal and prevents corrosion products from accumulating in boiler or reactor water.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 6. Incidentally, the same parts as in the prior art are denoted by the same reference numerals, and the explanation thereof will be omitted. First, in this embodiment, a ceramic filter 5 using a ceramic filter as a feed water filtration device is installed between the energy saver 24 and the feed water heater 22 of the thermal power plant.
0 is set. The configuration of this ceramic filter 50 will be explained with reference to FIG. Figure 2 shows ceramic filter 5.
0'' is shown. The ceramic filter 50 is composed of a sealed container that can be opened and closed with a flange, and this container has a water supply inlet 51, a purified water supply outlet 52, and a concentrated liquid outlet 53. Three nozzles are provided.

There is also a partition plate 56 that divides the inside of the closed container into a filtration chamber 54 and a processing chamber 55, and a ceramic filter 57 is disposed on this partition plate 56 in a removable and liquid-tight manner.

The concentrate outlet 53 is connected to the circulation pump 62 and further connected to the water supply inlet 51 on the outlet side of the circulation pump 56 . Further, a concentrate extraction line 63 branches from the outlet of the circulation pump 56, passes through a heat exchanger 58 and a filter 59, and is connected to return the filtrate to the condenser 1. Filter 5
As for No. 9, it is preferable to use a hollow membrane filter of a total filtration type because it is excellent in terms of filtration water quality, differential pressure increase characteristics, and backflow regeneration. A backwash pure water supply line 6o is provided at the water supply outlet 52. Further, when the bypass line 61 is connected, the water supply inlet 51 and the water supply outlet 52 are short-circuited.

As a ceramic filter material, alumina An20.
A porous material made of In addition to this, filter characteristics,
In other words, ceramics that are good for treated water quality and differential pressure increase characteristics are zr02.5in2°Bed, The
2. 'Ca' (1, MgO, Y2O3 oxide single-phase ceramics, AQ203-ZrOhaAQ
A binary ceramic called 203-3in2 can be used.

The shape of the ceramic filter 57 may be a hollow tube as shown in FIG. 3, or a cylindrical or polygonal cylindrical porous ceramic base material as shown in FIG. 4 with multiple holes penetrating through the end surface. can be used. It is known that most of the insoluble solids such as corrosion products in the water supply have a diameter of several microseconds, and in order to remove such small particles, It has rabbit-like micropores. Specifically, the fifth
As shown in the figure, the inner surface of the through hole has an asymmetric multilayer structure with a micropore diameter, and only the surface is formed with micropores. In this way, since the micropores are smaller than the insoluble solids, solids will not enter the micropores and cause clogging, and the fluid will flow smoothly in the porous layer. Since it can be used in a variety of ways, there is less pressure loss. The micropores can also be formed on the outer surface to filter from the outer surface to the inner surface.

The operation will be explained based on the above configuration.

The high temperature (approximately 200 to 30°C (1°C)) feed water that exits the feed water heater 22 is filtered to remove undissolved solids by a ceramic filter 50, and is supplied to the furnace 25, which is a heat source. It is possible to remove 100% of insoluble solids with a particle size of a certain size or more regardless of the quality of the water on the side.Since the ionic components are removed in the desalination tower 10, the combination of these two The water quality within the plant can always be maintained below the limit value.In particular, the ability to remove the above-mentioned insoluble solids is several tens of times higher than that of conventional pre-coated filters or electromagnetic filters.

Let's explain the flow of fluid in a little more detail.

In FIG. 2, the supplied water passes through the filtration chamber 54 from the water supply inlet 51, and is filtered and concentrated while passing through the through hole of the ceramic filter 57.

As shown in FIG. 5, undissolved solids are removed from the fluid through the fine pores formed in the ceramic filter, and the processing liquid leaches out onto the outer surface. The processing liquid is collected in the processing liquid chamber 55 and passes through the purified feedwater outlet to the boiler. On the other hand, the concentrated liquid is supplied from the concentrated liquid outlet 53 to the water supply inlet 51 by the circulation pump 62.
Go back and recycle. This prevents undissolved solids from adhering to the fine pores on the inner surface of the ceramic filter 57 and forming a cake by keeping the flow rate flowing through the through holes of the ceramic filter 57 within a turbulent range, thereby reducing the filtration flow rate. This is commonly referred to as cross-flow filtration. The inner flow velocity at this time is 1 m/s to 5 m/s.
It is better to set it as s.

Figure 6 is an example of an experiment to see how the filtration flow rate changes under a constant pressure when the internal flow velocity is changed. , while a constant filtration flow rate is obtained, the internal flow velocity is 0.9 m/
If it is s, the filtration flow rate will decrease significantly and backwashing will be required frequently.

A portion of the concentrate is extracted from the concentrate discharge line 63,
After lowering the temperature to about 40° C. through a heat exchanger 58, it is filtered through a hollow membrane filter 59 to remove solids, and then returned to the condenser 1.

Ceramic filters will cause a slight increase in differential pressure during cross-flow filtration, but will gradually become clogged. Therefore, if the differential pressure exceeds the allowable value, backwashing as described below is performed.

First, in order to disconnect the ceramic filter 50 from the water supply system,
By operating a valve (not shown), the flow path is switched to the bypass line 61 during backwashing. During this time, the ceramic filter 5
Purification by 0 is not performed, but since it is for a short time, there is no problem.

Next, water is supplied from the pure water supply line 60 for backwashing, and is caused to flow back through the ceramic filter 57 to peel off the solid matter attached to the fine pores on the inner surface. Further, the waste water at this time passes through a concentration outlet 53 and a concentrated liquid discharge line 63, and is filtered and reconcentrated by a filter 59.

The ceramic filter 50 is recovered by the above operation.

After completion of recovery, connect the bypass line 61 to the ceramic filter 5
Switch to 0 and run water.

The above is feed water purification during normal operation, but next we will explain cleanup when starting up the plant. In the case of this embodiment, only a very small amount of blowing operation is required for cleanup as in the conventional case. First, the water held in the plant from condenser 1 is purified by blowing using the same procedure as before, but the water quality at this time is at a level where it can be purified to a certain degree (
The amount may be 1 to 10 ppm), and the amount may be approximately enough to discharge the accumulated water in the plant piping. Next, a line from the condenser 1 returns to the condenser 1 through piping 2, demineralization tower 10, feed water heaters 14 to 22, ceramic filtration feed water 50, furnace 25, and piping 27 to perform cold cleanup and hot cleanup. Do an up. Insoluble solids in the system are removed by approximately IQO% in the ceramic filter 50, and only the remaining ionic components need be removed in the demineralization tower 10.
Purification is completed in an extremely short time.

According to this embodiment, the following effects can be achieved.

■ First, water heaters 14 to 22, which could not be removed conventionally.
Corrosion products generated from the deaerator 17, condensate boost pump 12, boiler feed water pump 19, etc. can be removed during normal plant operation, and scale adhesion inside the furnace 25 can be prevented. Therefore, it is possible to prevent a decrease in the thermal efficiency of the plant and maintain high efficiency at all times. Unlike conventional filters using polymeric materials, the ceramic filter 57 can be used even at high temperatures and low temperatures, and is suitable for use in water supply systems. In addition, filters that use magnetic force, such as electromagnetic filters currently being developed as high-temperature filters, can only remove paramagnetic solids, whereas ceramic filters can remove 100% of solids over a certain particle size in water supply. Therefore, extremely good water quality can be obtained.

■Secondly, the amount of blowing operation that was previously required can now be reduced to an extremely small amount. This is due to the use of the ceramic filter 50 in addition to the conventional purification of only the debasing 10. That is, this ceramic filter 50 can remove 100% of insoluble solids as long as they have a certain particle size or more, regardless of the quality of the water on the primary side.

In this way, the amount of blowing operation has been reduced to an extremely small amount, which eliminates the consumption of pure water for blowing and eliminates the need for wastewater treatment after blowing.Furthermore, the equipment used for blowing has become smaller and has a smaller capacity. Things can be used.

■ In addition to reducing the amount of blowing, the removal rate of undissolved solids has improved, so the cleanup time required for circulation operation after blowing can be reduced. Therefore, the total time required for cleanup at the time of plant start-up is extremely short. (172 to 1/4) (1) Furthermore, conventional cleanup operation is performed every time the plant is stopped and restarted, and in this sense, by shortening the cleanup time, the plant can be started up quickly. This is extremely effective considering that thermal power plants are increasingly used for load fluctuations and are frequently started and stopped.

■ Plant operation rate improves due to shorter cleanup times. This, along with improved plant thermal efficiency, improves plant utilization, making it possible to cover the necessary power demand with fewer plants than before.

(Other examples) Another embodiment of the present invention will be described with reference to FIG.

In this embodiment, a ceramic filter 50 is used to purify the water supply to the reactor 100 of a nuclear couplant, and a ceramic filter 150 is provided between the feed water heater 122 and the reactor 100. The action is similar to that of a thermal power plant.

The above embodiment has the following effects.

■ First, water heaters, pumps, and
Undissolved solids (crud) such as corrosion products generated from plants can be removed during plant operation. Therefore, reactor 1
Accumulation and adhesion of crud inside the 00 can be prevented. the current,
Most of the radiation exposure of workers during periodic plant inspections is due to cobalt-60, etc., which is a corrosion product that is activated in the reactor, and by reducing the amount of crud brought into the reactor, these sources of exposure can be reduced. can be removed.

■ Cleanup operation at plant start-up can be significantly shortened. This is because the ability of the ceramic filter to remove undissolved solids is much better than that of conventional pre-coated filters. Currently, the items needed for 1-2 weeks are approximately 1-
The process can be completed in 3 days, making it possible to improve operating rates.

It should be noted that the present invention is not limited to the above embodiments, and various configurations are possible. For example, the configuration of the ceramic filter may be other than that shown in FIG. 2. It goes without saying that the present invention can be applied not only to boiling water power plants but also to pressurized water nuclear power plants.

〔Effect of the invention〕

As detailed above, according to the feed water purification device according to the present invention, it is possible to remove almost 100% of the undissolved solid content in the feed water, and it is possible to prevent a decrease in thermal efficiency due to scale in a thermal power boiler and to reduce the exposure of an atomic coupler to radiation. It becomes possible. Also,
The cleanup time at plant start-up can be significantly shortened, and the plant operating rate and utilization rate can be improved, among other benefits.

[Brief explanation of the drawing]

FIGS. 1 to 6 are diagrams showing one embodiment of the present invention.
The figure shows the configuration of a thermal power plant, Figure 2 is a detailed diagram of the system configuration of the ceramic filter, Figures 3 and 4 are diagrams showing the shape of the ceramic filter, and Figure 5 is the diagram of the ceramic filter. An enlarged cross-sectional view, Figure 6 is a diagram showing the experimental results of the flow rate and filtration flow rate in the ceramic filter, and Figure 7 is
This figure is a block diagram of a nuclear power plant according to another embodiment, and FIGS. 8 and 9 are diagrams showing the structures of a conventional thermal power plant and a nuclear power plant. 50.150...Ceramic filter 57...Ceramic filter 1.101...Condenser 25...Furnace 100...Reactor agent Patent attorney Noriyuki Chika Ken Yudo Daishimaru Ken

Claims (1)

[Claims] The condensate condensed and liquefied in the condenser is purified by a condensate desalination device, heated through multiple feed water heat exchangers or deaerators, and then transferred to a heat source device, where it is converted into steam. This feed water purification device for a power plant generates steam and supplies it to a turbine device, and the steam that has done work in the turbine device is collected in the condenser and condensed and liquefied again. 1. A water supply purification device comprising a ceramic filtration device installed between a container and a heat source device, the ceramic filtration device having a large number of filters made of permeable ceramic arranged therein.