JPS5987090A - Filtering desalinator - Google Patents

Abstract

PURPOSE:To improve the filtering life and the filtering desalination power of the titled desalinator, by supplying water to a space between the group of filter elements from the upper and lower end bounds of the filter elements vertically provided, and precoating the filter elements with an assistant along a vertical direction. CONSTITUTION:The upper end of a filter element is provided at a ceiling plate 22 forming a filtering desalination chamber, while its lower end is equipped with a pipe part for withdrawal of a desalinated filtrate in a manner such that said pipe part extends through a bottom plate 21 to seal introduced water and the desalinated filtrate from each other. Guide plates 23, 24 for introducing streams of water to a space between the group of the elements from the lower position of the elements are provided at a water supply pipe 15 in correspondense to the elements. In precoating the elements with a filtering assistant, slurry of predetermined concentration is introduced in a predetermined flow rate through the pipe 15. A part of the introduced slurry is diffused along a horizontal direction by the guide plates 23, 24. The slurry from the guide plate 23 is spread to a far area while that from the guide plate 24 is spread to near area. Both of them rise through the space between the group of the elements.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a zero-go filtration desalination device that precoats a filter aid, and particularly relates to a multi-tube filtration desalination device used for purifying condensate in nuclear power plants. Regarding salt equipment.

[Prior art]

Figure 1 shows the water treatment systems of the nuclear power plant (condensate saponification system and reactor water purification system at the BWE port. In the figure, the steam generated in reactor 1 (286°C, 170 kg/cm") is passed through steam pipe 2. The water then rotates the turbine 3 to generate electricity, and then flows into the condenser 4 where it is condensed and condensed into water.Condenser 4
The water is led by a condensate purification system piping 15 and sent to a p-super desalination device 6 by a pump 5. In the p over-demineralizer 6,
Crud generated in the condensate purification system (Crud is a general term for fine suspended matter that is mainly composed of corrosion products in the condensate purification system and does not pass through the 0.45μ!n Silibore filter, and the main component is Fe. , 03 + peso, etc.) and nuclide ions are pre-coated on the outer diameter surface of the cylindrical element with resin prepared by mixing cation and anion powder ion exchange resin in a specific ratio to a thickness of several sections. Water is purified by filtration and desalination through the resin layer. The water purified by the filtration demineralizer 6 is then sent to the demineralizer 7, and is removed by the filtration demineralizer 6 by stacking anion and cation granular ion exchange resins in the demineralizer. Residual cladding and nuclide ions that were not removed are supplementally desalted. The purified water that has passed through the demineralizer 7 is heated by a low-pressure feedwater heater 1 (heater 8), sent to a high-pressure feedwater heater IO by a pump 9, heated again at high pressure, and returned to the reactor 1. In this way, the steam generated in the nuclear reactor drives the turbine, then is purified as condensate and returned to the reactor, so it is constantly circulated through the condensate purification system.

On the other hand, some of the reactor water is returned to the reactor by the pump 11 through the reactor water purification system piping 16, and the rest is sent to the cooler 12. The reactor water cooled by the cooler 12 is sent to the reactor water purifier 14 by the pump 13, and after being purified, it is returned to the reactor. The structure of the reactor water purifier 14 is the same as that of a condensate salter, and is designed to circulate reactor water, filter it, desalt it, and purify it.

FIG. 2 is an elevational cross-sectional view showing the general outline of the internal structure of the driven filtration demineralizer. The inside of the filtration demineralizer has an outer diameter of 50φ and a total length of 1.
It is a multi-tube filtration device in which more than 200 cylindrical filtration elements 30 of about 5 m are installed at intervals of about 80 gardens. The upper end of the filtration element is attached to the ceiling plate 22 by a hanging fitting, and the lower end is installed with a filtration water extraction pipe passing through the bottom plate 21, and the filtration demineralized water 18 from each filtration element is installed.
will gather in room 25. General theory Umbrella-shaped guide plates 23 and 24 are provided at the outlet of the water supply pipe 15 into the salt chamber, so that the introduced water flows evenly between the element groups.

Figure 3 shows an outline of the filter element structure and the state of the p-salt layer. The filtration element is made by bundling and twisting ultrafine fiber threads and wrapping them around a membrane-hole cylindrical support material 32.
A p-supersupporting layer 31 having a thickness of several 0.0 mm is formed, and by itself can filter and remove particles with a particle size on the order of microns. Table 11+1
is pre-coated with a powdered ion exchange resin with an average particle size of several tens of micrometers, forming an auxiliary vortex layer 33.The introduced water 17 rises along the element and passes through the filter layer. It is filtered and desalinated, and the commonly known salt water is extracted from the inside.

The filter aid is precoated onto the element by introducing it from the same water supply pipe as the p-filter layer of water. Precoating is done by introducing a slurry (resin mixed water with resin concentration of 0.5 to Iwt%) at a linear velocity (L, V) relative to the element surface area, usually 3 to 4 m/h. The formation layer is not averaged over the entire element, and as shown in FIG.
000 or more, it becomes extremely thin. Also LV, 6.5
．． In the case of 10 m/h (7), the precoat formation at the upper position is improved, but because the flow velocity near the 0 position is high, the formation of the filter aid at the lower position is poor and it is easy to peel off.

If p-deviation salt treatment is performed in a state where the layer thickness of the auxiliary agent is uneven, the filtration and desalination rate of the treated water will be low in areas where the layer thickness is thin, and the state of volumetric filtration in the filtration mechanism will be affected. When the precoat layer is formed uniformly, the filtration differential pressure rises rapidly rather than gradually, which shortens the filtration life. 6. When the filtration differential pressure reaches the set pressure or higher, the precoat pressure increases rapidly. Peel off the agent and replace with new auxiliary agent. Therefore, the number of replacements increases, and the amount of used waste resin, that is, radioactive waste increases.

[Summary of the invention]

The present invention is intended to make the thickness of the auxiliary agent precoat layer formed on the filter element uniform throughout. FIG. 5 shows the results of pre-coating the element with the auxiliary agent at L V 4 m/b, collecting the glycolyte auxiliary agent from each position of the element, and measuring the sedimentation rate of the auxiliary agent in still water. Depending on the element position, the sedimentation rate of the adhesion aid is at position 10.
It rapidly decreases from 00 or above. This means that materials with light specific gravity are thinly pre-coated at the upper position, and it is thought that this is caused by the fact that materials with heavy specific gravity cannot reach the upper position. Therefore, FIG. 6 shows the rising speed of water flow between element groups for each LV. ,
At Ly4m/h, when the position is 1000 or more, the rising speed between the element groups becomes less than the sedimentation speed of the resin, 36m/h, so at positions above that, the slurry water reaches slowly, so the arrival time of the resin is The smaller the amount, the thinner the precoat forming layer becomes. Still LV 6, IQ
It was found that when increasing the velocity by m/h, the position of the element on the sedimentation velocity diagram also moved upward, but not completely. Therefore, the thickness of the precoat forming layer is uniform throughout.
In order to achieve this, it is necessary that the rate of rise is greater than the rate of resin sedimentation over the entire area of the element. The present invention has been made in consideration of the above matters.

[Embodiments of the invention]

FIG. 7 is a plan view showing the internal structure of the filtration demineralizer of the present invention. The upper end of the filtration element is attached to the ceiling plate 22 forming the D5 demineralization chamber, and the lower end is provided with a brine extraction pipe passing through the bottom plate 21 to seal the introduced water and the filtered demineralized water.

The water supply pipe 15 has guide plates 23.corresponding to the elements that guide the water flow between the element groups from the lower part of the element.
The guide plate 23 is provided so that the water flow reaches the side wall of the vessel, and the guide plate 24 is provided so that the water flow reaches the side wall of the vessel. A pipe 26 reaching the upper part of the guide plate 24 is provided so that a part of the introduced water rises and flows out from the upper end.
The setting is 7°28. The guide 27 is provided for a group of elements in a nearby area, and the guide plate 28 is provided for a group of elements in an unusual area. The filter membrane has a structure in which salt water is extracted from the lower end. Next, when glycoating the element with the p-superior agent, a slurry of a predetermined concentration is introduced through the pipe 15 at a predetermined flow rate. A portion of the introduced slurry is spread horizontally by the guide plates 23, 24, the slurry from the guide plate 23 spreads far away, the slurry from the guide plate 24 spreads nearby, and rises between the element groups.

On the other hand, some of the slurry rises up the pipe 26, and at the top,
By the guides 27 and 28, it is spread horizontally and the guide plate 2
Unlike B, the slurry diffuses into the vicinity from the guide plate 27, and while the slurry is flowing between the element groups, the P-filtered water is continuously removed from the inside of the P-filtering element, and the slurry is applied to the surface of the filtering element. A p-vortex layer of agent 29 is formed.

The formation of the p-superexciter layer is shown in FIG. The flow rate between the elements changes to form the p-superexciter layer shown in FIG. Flow velocity from the bottom upwards vb1 If the flow velocity from the top downwards is V, the figure is for the case of LV 4 m/h for the element, but ■ is the flow rate divided by the space area between the elements. pupil, the linear velocity LV per unit area is v at position a, = 105.5 m/h
, V4 = l 2m/11. ■ is V, ==9
．． 5m/11. This is the result of precoating the auxiliary agent under the condition of Wb=108.5 m/h. In case (2), the amount of the auxiliary agent reaching the upper position is small, so the precoat forming layer in that area is thin.

In case (2), the precoat layer is formed relatively uniformly, but the sedimentation speed of the resin is accelerated by the downward flow from the upper part, so when the upper LV is large, the precoat layer in the upper part becomes thicker. Also, there is a large amount of resin that settles without being glycated onto the element. ■ is a case where the downward flow LV is the same as the upward flow LV, where the downward flow LV is the resin sedimentation velocity V
The result is the value added to . Water flowing from above and below causes stagnation in the center of the element, but the precoat forming layer is formed uniformly over the entire element.

As described above, when precoating an auxiliary agent onto an element by introducing water to the outer periphery of the element from above and below, a uniform precoat layer can be formed if the sedimentation rate of the auxiliary agent used is taken into consideration. After the completion of pre-coating of the auxiliary agent, salt treatment operation begins, but the l and V relative to the element are gradually increased, and the operation is normally performed at 8 to IQ m/b.

〔Effect of the invention〕

In this method, since water is introduced into the element from two directions, it is possible to prevent the element precoat layer near the introduction port from peeling off due to an increase in flow velocity, which would occur due to an increase in LV compared to conventional methods when water is introduced from one direction. Since a uniform precoat layer is formed, the present invention is highly effective in improving filtration and desalting performance and filtration life.

[Brief explanation of drawings]

Figure 1 is a water purification system diagram at a nuclear power plant (BWR), Figure 2 is a structural diagram of the location of a conventional filtration demineralizer, Figure 3 is a filtration model diagram of a p-filtration element, Fig. 4 is a state diagram of the precoat layer, Fig. 5 is a sedimentation velocity diagram of the resin, Fig. 6 is a flow velocity diagram, and Fig. 7 is a structural diagram of the location of the p-general salt vessel of the present invention.
FIG. 8 is a flow model diagram outside the p-element, and FIG. 9 is a state diagram of the precoat forming layer according to the present invention. 6...p common salt vessel, 21...bottom plate, 22...ceiling plate, 23.24,27. '28... Information board, 26.
... Pipe, 29 ... (ejaculate oil (auxiliary agent), 3o ... P-damage element, 31 ... filtration element fiber layer, 32 ...
- Fiber layer support cylinder, 33... Filter aid precoat forming layer. 3rd Kankan 4 Kuchiryo'7 Kuchi 1st 1st day ■ ■ 4 is town η2 (Go Duff ■ I ¥), (4rLm) -559-

Claims (1)

[Claims] 1. A filtration/desalination device with a number of filter elements pre-coated with a filtration aid on the surface to allow water to permeate through the auxiliary filtration layer and filter layer, and to remove filtrated water from the inside of the filter element for desalination. A filtration and demineralization device 1t02 characterized in that water is supplied between the filter element groups from the upper and lower end regions of the upright filter elements, and the filter elements are precoated with an auxiliary agent from above and below. In item 1, there is also a filtration desalination system characterized by a structure in which a water supply pipe is located in the center of the device, and water flow guides are provided in the water supply pipes at positions corresponding to the lower and upper ends of the filter element.