WO2018182033A1

WO2018182033A1 - Water production method and water production device

Info

Publication number: WO2018182033A1
Application number: PCT/JP2018/014007
Authority: WO
Inventors: 川島　義之; 谷口　雅英; 寛生高畠
Original assignee: 東レ株式会社
Priority date: 2017-03-31
Filing date: 2018-03-30
Publication date: 2018-10-04
Also published as: JPWO2018182033A1

Abstract

A water production method that freely switches between the following: a first operation method for extracting all filtered water, which is a combination of upstream filtered water obtained from an upstream semipermeable membrane module or an upstream semipermeable element, and downstream filtered water obtained from a downstream semipermeable membrane module or a downstream semipermeable element; and a second operation method for separating the upstream filtered water and the downstream filtered water, and extracting only the upstream filtered water.

Description

Fresh water generation method and fresh water generation apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fresh water generation method and a fresh water generation device that allows raw water to permeate through a semipermeable membrane to obtain the permeated water, and more particularly to a fresh water generation method and a fresh water generation device that suppress deterioration of water quality due to operating conditions and operating conditions.

There are various water purification technologies for high-concentration solutions, and membrane separation methods using semipermeable membranes are used as an example of energy-saving and resource-saving processes. According to the reverse osmosis method, which is an example of a membrane separation method, a solution containing a solute such as salt is allowed to permeate through a reverse osmosis membrane at a pressure equal to or higher than the osmotic pressure of the solution, thereby reducing the liquid ( Permeated water) and concentrated water. This technology can obtain drinking water level water from, for example, seawater, brine, and water containing harmful substances, and it can also be used for industrial ultrapure water production, wastewater treatment, recovery of valuable materials, etc. It is used.

In the semipermeable membrane separation method, usually a plurality of semipermeable membrane elements are connected in series to one pressure vessel by connecting water collecting pipes located inside each semipermeable membrane element (this is called a module). ). The raw water supplied to the semipermeable membrane element on the module inlet side (upstream side) is supplied to the semipermeable membrane surface through a gap in the semipermeable membrane element, and is separated into permeated water and concentrated water. The separated permeated water is collected in a water collecting pipe and taken out from a permeated water outlet provided at the end of the module and connected to the water collecting pipe. At this time, the raw water is not uniformly supplied to the entire module, but the permeated water is separated in order from the upstream element, so the amount of raw water supplied decreases as it approaches the module outlet side (downstream side), The salt concentration increases. Along with this, the amount of permeated water also decreases, the concentration increases, that is, the permeated water quality deteriorates.

Such a phenomenon appears more prominently when the water temperature rises due to seasonal fluctuations. When the temperature rises, the semipermeable membrane expands to increase the pore diameter, and the viscosity decreases to increase the amount of permeated water and the salt permeability per unit area. The amount of raw water supplied to the downstream semipermeable membrane element decreases as the amount of water passing through the upstream semipermeable membrane element increases, and the downstream semipermeable membrane element obtains a small amount of permeated water with relatively poor water quality. It will be. At this time, in order to prevent deterioration of permeated water quality, the number of semipermeable membrane elements is reduced in advance, and when the water temperature is low, the operation pressure is increased to obtain a desired amount of permeated water. In addition, when the annual water temperature fluctuation increases, the operating pressure at the time of low water temperature may exceed the allowable pressure of the semipermeable membrane module, for example, 8.0 to 9.0 MPa. For example, the raw water concentration (concentration = TDS here) : Total Dissolved Solids) was 45000 mg / L, the operable temperature range was sometimes limited to about 40 ° C.

Factors that lower the permeated water quality include fouling (film surface contamination) and film deterioration. Fouling is caused by the growth of microorganisms, salt precipitation, and the like. The film deterioration is caused by the film surface being scratched by an insoluble material or the film being destroyed by an oxide such as hypochlorous acid. When these occur, the performance is restored by cleaning with chemicals, but irreversible changes accumulate, and the performance gradually deteriorates and the water quality deteriorates. At this time, if the number of semipermeable membrane elements is reduced, it becomes possible to obtain a desired water quality. However, in order to implement this, it takes a lot of time and labor, such as once stopping the operation. Replace with a new semi-permeable membrane element when the performance drops.

As a device and a method for operating stably by uniformizing the flow rate of raw water supplied to a semipermeable membrane element, Patent Document 1 discloses a reverse osmosis separation device for changing the cross-sectional area of a raw water flow path of a reverse osmosis membrane element in a module and its According to Patent Document 2, a reverse osmosis membrane treatment apparatus and a structure in which a shutter mechanism for blocking a water collecting pipe forming a flow path of permeated water and a valve mechanism for adjusting the flow rate of permeated water on the supply side (upstream side) are provided. In Patent Document 3, the water method includes a resistor that separates permeate water into a supply side (upstream side) and a discharge side (downstream side), and further includes a valve that adjusts the flow rate of permeate water on the supply side (upstream side). A provided reverse osmosis treatment apparatus is disclosed. However, in either case, the water quality deterioration due to temperature change or the like was not suppressed, and the operating range was not expanded or the replacement frequency of the semipermeable membrane element was not reduced.

Japanese Unexamined Patent Publication No. 2000-288356 Japanese Patent Laid-Open No. 2001-137672 Japanese Unexamined Patent Publication No. 2012-130838

In the conventional technology, in order to reduce the quality of the permeated water in this way, the number of semipermeable membrane elements is designed to be small in advance and operated at a high operating pressure in order to obtain a desired amount of permeated water, or the semipermeable membrane element It was dealt with by exchange. For this reason, there is a problem that the required power of the pump is increased and the power cost is increased, the replacement cost of the semipermeable membrane element is increased, and the designable temperature range is limited.

The present invention suppresses permeate quality degradation even when permeate quality declines, lowers operating pressure and replacement frequency of the semipermeable membrane element, lowers the operating cost of the fresh water generator, and can be designed at the same time. An object of the present invention is to provide a wide water production method and water production apparatus.

In order to solve the above-mentioned problems, the present invention provides a fresh water generation method for separating raw water with a semipermeable membrane and discharging concentrated water to take out the permeated water. The raw water supply port, the concentrated water discharge port, the semipermeable membrane, A semipermeable membrane element comprising a water flow channel, a permeated water flow channel, and a water collecting pipe for collecting and taking out the permeated water, so that the concentrated water discharged from the former semipermeable membrane element is supplied as raw water to the latter semipermeable membrane element. An upstream semipermeable membrane module located on the upstream side, in which the m semipermeable membrane elements (m is an integer of 2 or more) are communicated, including a semipermeable membrane module communicated via a water collecting pipe; A downstream semipermeable membrane module located on the downstream side, in which p semipermeable membrane elements (p is a natural number satisfying p <m) are connected, and a first raw water supply connected to the upstream semipermeable membrane module Pathway, discharged from the upstream semipermeable membrane module Concentrated water connection path connected so that upstream concentrated water is supplied as raw water to the downstream semipermeable membrane module, upstream permeated water obtained from the upstream semipermeable membrane module, and the downstream semipermeable membrane module A permeate connection path connected to join the downstream permeate obtained from the first semiconducting water discharge path connected to the downstream semipermeable membrane module, the concentrated water connection path, and the permeate A first water generator including a configuration in which the upstream semipermeable membrane module and the downstream semipermeable membrane module are connected via a water connection path, or n semipermeable membrane elements (n is 3) The above integer) is connected, and resistance to the permeated water is reduced in the water collecting pipe located between the downstream semipermeable membrane element less than n / 2 counted from the downstream side and the remaining upstream semipermeable membrane element. Giving drain separator or also A semipermeable membrane module provided with a water collecting pipe valve, a second raw water supply path, a second concentrated water discharge path, and a downstream permeate extraction path for extracting downstream permeate obtained from the downstream semipermeable membrane element , Using either the upstream permeated water obtained from the upstream semipermeable membrane element or the second fresh water generator including a total permeated water take-out path, or the upstream semipermeable membrane module or the A first operation method of taking out the total permeated water obtained by combining the upstream permeated water obtained from the upstream semipermeable membrane element and the downstream permeated water obtained from the downstream semipermeable membrane module or the downstream semipermeable membrane element. And a fresh water generation method characterized in that the upstream operation water and the downstream operation water are divided and the second operation method for extracting only the upstream operation water is arbitrarily switched.
The present invention also relates to a fresh water generator that separates raw water with a semipermeable membrane and discharges concentrated water to take out permeated water. The raw water supply port, the concentrated water discharge port, the semipermeable membrane, the raw water channel, and the permeated water channel Concentrated water discharged from the former semipermeable membrane element is supplied to the latter semipermeable membrane element as raw water for m semipermeable membrane elements (m is an integer of 2 or more) equipped with a water collecting pipe for collecting and taking out the permeated water. As described above, the upstream semipermeable membrane module communicated through the water collecting pipe and the p semipermeable membrane elements (p is a natural number satisfying p <m) are discharged from the preceding semipermeable membrane element. A first raw water connected to the upstream semipermeable membrane module, including a downstream semipermeable membrane module communicating with a collecting pipe so that the concentrated water is supplied as raw water to the latter semipermeable membrane element; Supply path, discharged from the upstream semipermeable membrane module Concentrated water connection path connected so that upstream concentrated water is supplied as raw water to the downstream semipermeable membrane module, upstream permeated water obtained from the upstream semipermeable membrane module, and the downstream semipermeable membrane module Permeate connection path connected to join downstream permeate obtained from the above, a first concentrated water discharge path connected to the downstream semipermeable membrane module, and permeate connection path switching capable of switching the flow path And a downstream permeated water discharge path connected to the permeated water connection path switching section.
The present invention also relates to a fresh water generator that separates raw water with a semipermeable membrane and discharges the concentrated water to take out the permeated water. The raw water supply port, the concentrated water discharge port, the semipermeable membrane, the raw water flow path, the permeated water flow Concentrated water discharged from the former semipermeable membrane element is used as raw water for the semipermeable membrane element in the latter stage. The upstream semipermeable membrane module communicated through the water collecting pipe and p semipermeable membrane elements (p is a natural number satisfying p <m) are discharged from the preceding semipermeable membrane element so as to be supplied. A first semi-permeable membrane module connected to the upstream semi-permeable membrane module, including a downstream semi-permeable membrane module communicating with a water collecting pipe so that the concentrated water is supplied as raw water to the latter semi-permeable membrane element. Discharge from raw water supply channel, upstream semipermeable membrane module The concentrated water connection path connected so that the upstream concentrated water is supplied as raw water to the downstream semipermeable membrane module, the upstream permeated water obtained from the upstream semipermeable membrane module, and the downstream semipermeable membrane module The permeated water connection path connected to join the downstream permeate obtained from the first semi-concentrated water discharge path connected to the downstream semipermeable membrane module, provided at a location different from the permeate connection path. Upstream permeate or upstream permeate combined with upstream permeate and downstream permeate, or permeate connection path that can be switched between opening and closing provided in the permeate connection path. Provided is a fresh water generator characterized by comprising a water connection path valve.
The present invention is also a water making apparatus comprising a high-pressure pump for boosting raw water, separating the raw water with a semipermeable membrane, discharging concentrated water and taking out the permeated water, the raw water supply port, the concentrated water discharge port, the semipermeable membrane Concentrated water discharged from the former semipermeable membrane element is the latter stage of n semipermeable membrane elements (n is an integer of 3 or more) having a membrane, raw water flow channel, permeated water flow channel, and a water collecting pipe for collecting and taking out permeated water. A semipermeable membrane module communicating with a semi-permeable membrane element so as to be supplied as raw water to the semipermeable membrane element, wherein the semipermeable membrane module includes a second raw water supply path and a second concentrated water discharge path. , A downstream permeated water extraction path for extracting downstream permeated water obtained from less than n / 2 semipermeable membrane elements counted from the downstream side in the semipermeable membrane module, and an upstream obtained from the remaining semipermeable membrane elements Upstream permeate to remove side permeate or A water collecting pipe partitioning section provided with a water collecting pipe on the upstream side of the semipermeable membrane element at a position of less than n / 2 counting from the downstream side, provided with a permeated water extraction path, and the downstream A flow rate or flow path control unit for controlling the flow rate or flow path provided in the side permeate extraction path, or the upstream side of the semipermeable membrane element at a position of less than n / 2 counting from the downstream side In addition to the water collecting pipe valve provided in the water collecting pipe and capable of switching between opening and closing, it is provided with at least one of a water stop part or a flow rate or a flow path control part provided in the downstream permeate water extraction path. A water freshening device is provided.

According to the fresh water generation method of the present invention, when the permeated water quality is lowered, it is possible to suppress the degradation of the permeated water quality by taking out only the upstream permeated water, and when the permeated water quality is good, the upstream permeated water and the downstream The required power of the pump can be suppressed by taking out the total permeated water combined with the side permeated water. Therefore, the temperature range in which operation can be performed is widened, and economical operation is possible by reducing the replacement frequency of the semipermeable membrane element and reducing the electricity cost.

FIG. 1 is an example of a fresh water generator according to an embodiment of the present invention. FIG. 2 is an example of a fresh water generator having a permeate connection path valve and no downstream permeate discharge path according to another embodiment of the present invention. FIG. 3 is an example of a desalinator according to another embodiment of the present invention in which the downstream permeate discharge path is connected to the first raw water supply path. FIG. 4 is an example of a fresh water generator including a semipermeable membrane module provided with a water collecting pipe partitioning section or a water collecting pipe valve according to another embodiment of the present invention. FIG. 5 is an example of a water producing device according to another embodiment of the present invention in which the downstream permeate take-out path is connected to the upstream permeate extract or the total permeate take-out path. FIG. 6 is an example of a desalinator according to another embodiment of the present invention, in which the downstream permeate take-out path is connected to the upstream permeate or total permeate take-out path and the second raw water supply path. FIG. 7 is an example of a water producing device according to another embodiment of the present invention, in which the downstream permeate take-out path is connected to the upstream permeate or total permeate take-out path and the downstream permeate discharge path. FIG. 8 is an example of a water producing device according to another embodiment of the present invention, in which semipermeable membrane modules including a semipermeable membrane module provided with a water collecting pipe partitioning section or a water collecting pipe valve are arranged in multiple stages. FIG. 9 is a schematic view of a spiral type reverse osmosis membrane element according to an embodiment of the present invention.

Hereinafter, embodiments of the invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram of a desalination apparatus suitable for a desalination method according to a preferred embodiment of the present invention. This apparatus includes a high-pressure pump 29, a first raw water supply path (raw water supply path) 1, an upstream side semi-permeable. Membrane module 22, downstream semipermeable membrane module 23, first concentrated water discharge path (concentrated water discharge path) 2, upstream permeated water or total permeated water extraction path 3, concentrated water connection path 8, permeate connection path 9 The downstream permeated water discharge path 10 is composed of an upstream semipermeable membrane module 22 and a downstream semipermeable membrane module 23 connected by a concentrated water connecting path 8 and a permeated water connecting path 9. Further, the permeate connection path 9 is provided with a permeate connection path switching unit or a permeate connection path valve 28, and the permeate connection path switching unit or the permeate connection path valve 28 is connected to the downstream permeate discharge path 4. It is connected.

The upstream side semipermeable membrane module 22 has m semipermeable membrane elements (m is a muffler element) including a raw water supply port, a concentrated water discharge port, a semipermeable membrane, a raw water flow channel, a permeate flow channel, and a water collecting pipe for collecting and taking out permeate. 2 or more) is loaded through the water collecting pipe so that the concentrated water discharged from the former semipermeable membrane element is supplied as raw water to the latter semipermeable membrane element. The membrane module 23 is loaded with p semipermeable membrane elements (p is a natural number satisfying p <m) in the same manner as the upstream membrane membrane 22.

The raw water pressurized by the high-pressure pump 29 is introduced into the upstream semipermeable membrane module 22 through the first raw water supply path 1. The introduced raw water is subjected to a semipermeable membrane treatment by a semipermeable membrane element, and the permeated water is collected in a water collecting pipe by a gap provided by a permeated water flow path material, and is connected to the water collecting pipe through the water collecting pipe. Or it is led to the total permeate extraction path 3 or permeate connection path 9. The concentrated water that has not permeated through the semipermeable membrane element is introduced as raw water into the semipermeable membrane element arranged on the downstream side, and the permeated water is taken out from the upstream side permeated water or the total permeated water connected to the water collecting pipe as described above. It is guided to the path 3 or the permeate connection path 9. In the semipermeable membrane element located on the most downstream side of the upstream semipermeable membrane module, the permeated water is the upstream permeated water or total permeated water extraction path 3 connected to the water collecting pipe as described above, or the permeated water connecting path 9. The concentrated water is introduced as raw water into the downstream semipermeable membrane module 23 disposed on the downstream side via the concentrated water connection path 8.

The concentrated water discharged from the downstream semipermeable membrane module 23 is discharged to the outside of the downstream semipermeable membrane module 23 through the first concentrated water discharge path 2, and the permeated water is connected to the water collecting pipe through the water collecting pipe. Guided to connection path 9.

Here, the permeate connection path switching unit or the permeate connection path valve 28 is a three-way valve, one through the permeate connection path 9 to the upstream semipermeable membrane module 22 and the other through the permeate connection path 9. The downstream semipermeable membrane module 23 is connected to the downstream permeate discharge path 10.

Therefore, if the direction of the upstream semipermeable membrane module 22 and the downstream semipermeable membrane module 23 is opened and the direction of the downstream permeated water discharge path 10 is closed, the permeated water obtained from the upstream semipermeable membrane module 22 is obtained. All the permeated water (total permeated water) including the permeated water (downstream permeated water) obtained from the (upstream permeated water) and the downstream semipermeable membrane module 23 is taken from the upstream permeated water or the total permeated water extraction path 3. It is taken out. Alternatively, if all the directions of the upstream semipermeable membrane module 22, the downstream semipermeable membrane module 23, and the downstream permeated water discharge path 10 are opened, the upstream permeated water or the total permeated water extraction path 3 or the downstream permeated water. Total permeated water can be taken out from both of the discharge paths 10. The operation method for taking out the total permeated water in this way is referred to as a first operation method.

Further, if the direction of the upstream semipermeable membrane module 22 is closed and the direction of the downstream semipermeable membrane module 23 and the downstream permeated water discharge path 10 is opened, the upstream permeated water can be the upstream permeated water or the total permeated water. The water is extracted from the water extraction path 3 and the downstream permeate is discharged from the downstream permeate discharge path 10. The operation method in which the upstream permeate water and the downstream permeate water are divided in this way to extract only the upstream permeate water is referred to as a second operation method.

When the amount of permeated water obtained from the upstream semipermeable membrane element increases due to an increase in the temperature of the supplied water due to seasonal fluctuations, the downstream semipermeable membrane module obtains a small amount of permeated water having relatively poor water quality. At this time, by switching from the first operation method to the second operation method, the downstream permeate having a small amount of water and poor water quality is removed, and as a result, the amount of permeate (upstream permeate only) obtained from the water generator. The deterioration of water quality is suppressed while maintaining

As a standard for performing the above-described operation, any method can be used as long as it is possible to directly or indirectly determine the deterioration of the quality of the total permeated water. Raw water, concentrated water, upstream permeated water, downstream permeated water, total permeated water Any one or more of these can be used as a judgment material, such as water temperature, amount of water, and water quality (salt concentration). For example, if any of the water temperatures exceeds 35 ° C., the quality of the upstream permeated water (salt concentration) exceeds 800 mg / l, the quality of the downstream permeated water exceeds 2000 mg / l, the upstream side When the ratio of the amount of downstream permeated water to the permeated water is less than 10%, when the quality of the total permeated water exceeds 900 mg / l, the first operating method may be switched to the second operating method.

Alternatively, when the above water quality deterioration occurs, salt concentration hardly occurs in the downstream semipermeable membrane module, so the ratio of the downstream concentrated water quality (salt concentration) to the upstream concentrated water quality is 105%. What is necessary is just to switch from the 1st driving | running method to the 2nd driving | running method, when it falls below.

In addition, the reference | standard which switches an operation method is not limited to the above, You may change suitably according to the water quality and water quantity calculated | required according to a project.

In addition, since the above-described operation can be performed regardless of whether the fresh water generator is operating or stopped, the above-described operation may be performed at an arbitrary timing.

Here, in order to secure the amount of permeated water in the first operation method, the number of semipermeable membrane elements loaded in the upstream semipermeable membrane module 22 is m (m is an integer of 2 or more), and the downstream semipermeable membrane. When the number of semipermeable membrane elements loaded in the element is p (p is a natural number), it is necessary to satisfy p <m.

As a form of the semipermeable membrane element, there are a method in which a flat membrane is incorporated in a spiral, tubular or plate-and-frame element, and a hollow fiber is bundled and used in the element. Although it does not depend on these forms in the present invention, it is preferable that the flat membrane spiral type has a large amount of permeated water to be taken out, and the raw water and the downstream semipermeable membrane supplied to the upstream semipermeable membrane module. Since the difference in the amount and concentration of raw water supplied to the module increases, it is preferable for obtaining the effects of the present invention.

FIG. 9 is a conceptual diagram of a spiral-type semipermeable membrane element, in which a semipermeable membrane 40, a raw water channel material 41 located on the raw water side of the semipermeable membrane, and a permeated water channel material 42 located on the permeate side of the semipermeable membrane. The water collecting pipe 24 collects the permeated water 32. The raw water 30 flows into the spiral semipermeable membrane element, and the concentrated water 31 is discharged.

The semipermeable membrane module connects a plurality of semipermeable membrane elements via a collecting pipe so that the concentrated water obtained from the former semipermeable membrane element is supplied to the latter semipermeable membrane element as raw water, and is connected in series to a pressure vessel. Is in the box. There is no particular limitation on the number of elements, but 4 to 8 elements are preferably incorporated. Moreover, what arrange | positioned this semipermeable membrane module in parallel is called a semipermeable membrane module unit, The combination, the number, and arrangement | sequence can be arbitrarily performed according to the objective.

The water to be treated in the fresh water generator of the present invention is not particularly limited in view of the gist of the present invention, but may be seawater, brackish water, high-concentrated brackish water having a solute concentration in the solution of 0.5% by weight or more. For example, the difference in the amount and concentration of the raw water supplied to the upstream semipermeable membrane element and the raw water supplied to the downstream semipermeable membrane element is increased, which is preferable because the effects of the present invention are sufficiently exhibited. More preferably, the raw water concentration is 30000 mg / L or more seawater or high-concentration brine.

The operating conditions of the fresh water generator of the present invention are not particularly limited in view of the gist of the present invention, but the recovery rate representing the amount of permeated water recovered relative to the amount of raw water is 30% or more. If it exists, the raw | natural water density | concentration supplied to a semi-permeable membrane element of a latter stage will become high, and the effect of this invention is fully exhibited, and is preferable.

FIG. 2 is a conceptual diagram of a fresh water generator according to another embodiment suitable for the fresh water generation method of the present invention. The permeate connection path switching unit or the permeate connection path valve 28 is a valve that can be switched between open and closed. There is no permeate extraction path. Here, if the permeate connection path switching part or the permeate connection path valve 28 is opened, the first operation method is taken, and if the permeate connection path switching part or the permeate connection path valve 28 is closed, the second operation method is taken. You can take a driving method.

The water collecting pipe of the downstream semipermeable membrane module, the downstream permeated water connecting route 9 located between the downstream semipermeable membrane module 23 and the permeated water connecting route switching unit or the permeated water connecting route valve 28, and the permeated water. The connection path switching unit or the permeate connection path valve 28 is preferably pressure-resistant since pressure is applied when the downstream permeate is stopped, and more preferably can be assumed as the operating pressure on the raw water side. It is preferable to have pressure resistance that can withstand 0.0 MPa.

The permeated water connection path switching unit or the permeated water connection path valve 28 may be connected to the first raw water supply path 1 via the raw water confluence path 6 as shown in FIG. Here, if the permeate connection path switching unit or the permeate connection path valve 28 is opened in the direction of the upstream semipermeable membrane module 22 and the downstream semipermeable membrane module 23 and the direction of the raw water merging path 6 is closed, The first driving method is taken. Moreover, if the direction of the upstream semipermeable membrane module 22 is closed and the direction of the downstream semipermeable membrane module 23 and the raw water merge path 6 is closed, the second operation method is taken.

At this time, in the second operation method, it is possible to lower the raw water concentration and lower the required power of the high pressure pump.

The permeated water connection path switching unit or the permeated water connection path valve 28 may be a gate valve, a globe valve, a two-way ball valve, a three-way ball valve, a butterfly valve, a Λ port valve, or the like. A gate valve or a globe valve excellent in performance is preferable, and a three-way ball valve is preferable when used for switching the flow path.

FIG. 4 is a conceptual diagram of a fresh water generator according to another embodiment suitable for the fresh water generation method of the present invention. The fresh water generator includes a semipermeable membrane module 21, a second raw water supply path (raw water supply path) 1, a first 2 from the concentrated water discharge path (concentrated water discharge path) 2, the upstream permeate or total permeate take-out path 3, the downstream permeate take-out path 4, the high-pressure pump 29, the water stop portion or the flow rate or the flow path control section 25. Thus, the semipermeable membrane module 21 is loaded with a plurality of semipermeable membrane elements 20 connected through a water collecting pipe. Further, the water collecting pipe 24 positioned between the

semipermeable membrane elements

20b and 20c is provided with a water collecting pipe separating section 26 or a water collecting pipe valve 27 having a function of giving resistance to the permeated water.

Here, if the water collecting pipe delimiter 26 or the water collecting pipe valve 27 is open, the first operation method is adopted, and the permeated water that has passed through the

semipermeable membrane elements

20a, 20b, and 20c is not separated, and the upstream side It is taken out from at least one of the permeated water or total permeated water take-out path 3 or the downstream permeate take-out path 4.

If the water collecting pipe delimiter 26 or the water collecting pipe valve 27 is closed, the second operation method is adopted, and the permeated water that has permeated the

semipermeable membrane elements

20a and 20b passes through the upstream permeated water or the total permeated water extraction path 3. The permeated water taken out and permeated through the semipermeable membrane element 20 c is taken out through the downstream permeated water take-out path 4. Further, the permeated water that has permeated the semipermeable membrane element 20 c passes through the downstream permeated water extraction path 4, and is downstream permeated by the water stop portion or the flow rate or the flow path control unit 25 provided in the downstream permeated water extraction path 4. It can be switched between taking out the water with the upstream permeate water, stopping the water, returning it to the raw water, discharging it with the concentrated water, or taking it out for another use.

In order to secure the amount of permeated water in the first operation method, the water collecting pipe delimiter 26 or the water collecting pipe valve 27 sets the number of semipermeable membrane elements loaded in the semipermeable membrane module 21 (n is an integer of 3 or more). ), It is necessary to install it on the upstream side of the semipermeable membrane element at a position of less than n / 2 counting from the downstream side.

In particular, the more the semipermeable membrane element is located on the downstream side, the lower the amount of raw water supplied to the semipermeable membrane element, and the quality of the permeated water deteriorates. More preferably, it is installed on the upstream side of the semipermeable membrane element located on the downstream side.

The water collecting pipe separator 26 or the water collecting pipe valve 27 described above only needs to give resistance to permeated water, and plugs, caps, flanges, orifices, gate valves, globe valves, ball valves, and the like can be used. The material is iron, stainless steel, aluminum, aluminum alloy, nickel, nickel alloy, copper, copper alloy, silver, silver alloy, gold, gold alloy, platinum, platinum alloy, titanium, titanium nickel alloy, indium alloy, alumina, Aluminum oxide, silicon carbide, silicon nitride, zirconia, aluminum nitride, natural rubber, butyl rubber, urethane rubber, silicone rubber, fluororubber, polybutylene terephthalate, polyethylene terephthalate, polyethylene sulfide, low density polyethylene, high density polyethylene, polyvinyl chloride, Polypropylene, polystyrene, polyacetal, polyamide, polyamideimide, polyetheretherketone, polyphenylene sulfide, polytetrafluoroethylene, polyacetal, polycarbonate, polyphenylene ox De, polyurethane, polylactic acid, methacrylic resin, AS resin, ABS resin, phenol resin, urea resin, epoxy resin, melamine resin, unsaturated polyester resin, Noryl resin, or the like may be used FRP. In the present invention, any material is effective, but it is more preferable to use stainless steel, noryl resin, FRP, or polyethylene terephthalate that is less leached into permeated water and has excellent corrosion resistance, chemical resistance, and pressure resistance.

Although the operation method of the water collection pipe valve 27 of this embodiment is effective in any case, since it can be operated without opening the semipermeable membrane module 21, it can be operated from the outside of the semipermeable membrane module 21. The thing which can be operated by non-contact using infrared rays etc. from the exterior of the semipermeable membrane module 21 is more preferable.

Instead of the above-described water collecting pipe delimiter 26 or the water collecting pipe valve 27, a porous body that allows a part of the permeated water to pass therethrough may be used, and a shape memory alloy that changes the degree of opening and closing according to the water temperature may be used.

The water stop or flow rate or flow path control unit 25 provided in the downstream permeate take-out path 4 uses a gate valve, a globe valve, a two-way ball valve, a three-way ball valve, a butterfly valve, a Λ port valve, or the like. When stopping water, a gate valve or a globe valve having excellent pressure resistance is preferable, and when controlling the flow path, a three-way ball valve is preferable.

The above-described water collecting pipe separator 26 or water collecting pipe valve 27, the downstream permeated water extraction path 4 located between the semi-permeable membrane module 21 and the water stop part or flow rate or flow path control part 25, and the water stop part or flow rate. Since the pressure is applied when the downstream permeate is stopped or the flow rate is controlled, the flow path control unit 25 preferably has pressure resistance, and more preferably can be assumed as the operating pressure on the raw water side. It is preferable to have pressure resistance that can withstand 0 MPa.

FIG. 5 is a conceptual diagram of a fresh water generator in which a flow path is added to the fresh water generator of FIG. 4, and the water stop or flow rate or flow path controller 25 provided in the downstream permeate take-out path 4 is a permeate merge. The upstream permeated water or the total permeated water extraction path 3 is connected via the path 5. Here, the water collecting pipe delimiter 26 or the water collecting pipe valve 27 is opened and the flow path control section 25 is opened or closed, or the water collecting pipe delimiter 26 or the water collection pipe valve 27 is closed and the water stop section or the flow rate or flow path control section. If 25 is open, the first operation method is used, and if the water collecting pipe separator 26 or the water collecting pipe valve 27 and the water stop or flow rate or flow path control unit 25 are both closed, the second operation method is used. Can do.

As shown in FIG. 6, the water stop or flow rate or flow path control unit 25 is connected to the upstream permeate or total permeate take-out path 3 via the permeate merge path 5, and in addition, the second stop via the raw water merge path 6. The raw water supply path 1 may be connected. At this time, the water stop portion or the flow rate or the flow path control section 25 is a flow path control section, and a water collection pipe partition section 26 or a water collection pipe valve 27 is installed in the water collection pipe. Here, if the water collecting pipe delimiter 26 or the water collecting pipe valve 27 is opened or closed and the flow path control unit 25 is directed to the permeate merging path 5, the first operation method is adopted, and the water collecting pipe delimiter 26 or the water collecting pipe is used. If the valve 27 is closed and the flow path control unit 25 is directed to the raw water merge path 6, the second operation method is taken. Here, when the 2nd driving | running method is taken, raw power density | concentration can be lowered | hung and the required motive power of a high pressure pump can be lowered | hung.

Further, the water stop portion or the flow rate or the flow path control portion 25 may be connected to the upstream permeate water or the total permeate take-out route 3 via the permeate merge passage 5 as shown in FIG. In addition, it may be connected to the second concentrated water discharge path 2 via the downstream permeate discharge path 10. At this time, the water stop portion or the flow rate or the flow path control section 25 is a flow path control section, and a water collection pipe partition section 26 or a water collection pipe valve 27 is installed in the water collection pipe. Here, if the flow path control unit 25 is for the permeate merge path 5, the first operation method is used, and if the flow path control unit 25 is switched for the downstream side permeate discharge path 10, the second operation method is used. .

FIG. 8 is a conceptual diagram of a desalination apparatus in which semipermeable membrane modules are arranged in multiple stages and the concentrated water obtained from the former semipermeable membrane module 21a is supplied as raw water to the latter semipermeable membrane module 21b. The semipermeable membrane module 21b is similar to the semipermeable membrane module shown in FIG. 4 in that the water collecting pipe separator 26 or the water collecting pipe valve 27, the upstream permeate or total permeate takeout path 3, the downstream permeate takeout path 4, The water stop or flow rate or flow path control unit 25 is connected to the upstream permeate or total permeate take-out path 3 via the permeate merge path 5, It is connected to the second raw water supply path 1 via the raw water merge path 6.

At this time, the permeated water extraction method can be switched in the downstream semi-permeable membrane element having the lowest permeated water quality and the least permeated water amount in the apparatus, which is effective in suppressing deterioration of the permeated water quality.

The above-mentioned desalination apparatus has the above-described configuration such as the path connected to the semi-permeable membrane module 21b and the semi-permeable membrane module 21b in the subsequent stage, but is connected to the semi-permeable membrane module 21a and the semi-permeable membrane module 21a in the preceding stage. The route may be in the form described above, and both the preceding stage and the subsequent stage may be in the form described above.

Thus, according to the fresh water generation method and apparatus of the present invention described above, when there is a concern about deterioration of the quality of the total permeated water, only the upstream permeated water is taken out, thereby suppressing the deterioration of the quality of the permeated water obtained from the apparatus. can do.

Hereinafter, the present invention will be described with specific examples. In the examples, only the case where a spiral type reverse osmosis membrane element is used will be described. However, the present invention is not limited to these examples.

<Example 1>
As in the embodiment shown in FIG. 1, the high-pressure pump, the first raw water supply path, the upstream reverse osmosis membrane module, the upstream permeate or total permeate take-out path, the concentrated water connection path, the permeate connection path, and the downstream side A fresh water generator comprising a three-way valve provided in the reverse osmosis membrane module, the first concentrated water discharge path, the downstream permeate discharge path, and the downstream permeate connection path and connected to the downstream permeate discharge path was used. Here, the upstream reverse osmosis membrane module has an effective membrane area of 37 m ² , a salt removal rate of 99.75%, a permeated water amount of 24.6 m ³ / d, and a spiral reverse type having a maximum operating pressure of 8.3 MPa. Five osmotic membrane elements were loaded, and one downstream osmosis membrane element was loaded on the downstream reverse osmosis membrane module.

Operating conditions, assuming the matter to obtain industrial water from seawater in the Middle East, the raw water pH 7, the raw water TDS 45000mg / l, the raw water flow rate 200 meters ³ / d, the amount of the permeated water ^{80 m} 3 / d (recovery rate: 40%), and the upper limit of the permeate salt concentration was set to 900 mg / l.

First, the raw water temperature was set to 15 ° C., and the operation was continuously performed for 3 hours by the first operation method. At this time, the module inlet pressure was 7.65 MPa on average and the permeated water salt concentration was 206 mg / l on average.

Next, the raw water temperature was set to 45 ° C., and the operation was continuously performed for 3 hours by the second operation method. At this time, the module inlet pressure was 6.87 MPa on average and the permeated water salt concentration was 824 mg / l on average.

<Comparative Example 1>
The fresh water generator similar to Example 1 was used, and it was always operated by the first operation method regardless of changes in the operation conditions.

When the raw water temperature was 15 ° C. and the continuous operation was performed for 3 hours, the module inlet pressure was 7.62 MPa on average and the permeated water salt concentration was 213 mg / l on average, which was the same as Example 1.

Next, when the raw water temperature was 45 ° C. and the continuous operation was performed for 3 hours, the module inlet pressure averaged 6.53 MPa and the permeate salt concentration averaged 964 mg / l, which exceeded the upper limit of the permeate salt concentration. .

<Comparative example 2>
The fresh water generator similar to Example 1 was used, and it always drive | operated with the 2nd driving | running method irrespective of the change of the driving | running condition.

When the raw water temperature was 15 ° C. and continuous operation was performed for 3 hours, the module inlet pressure was 8.49 MPa on average and the permeated water salt concentration was 185 mg / l, which exceeded the maximum operating pressure of the reverse osmosis membrane element.

Next, when the raw water temperature was 45 ° C. and continuous operation was performed for 3 hours, the module inlet pressure was 6.91 MPa on average and the permeated water salt concentration was 830 mg / l on average, which was the same as in Example 1.
The results of Examples and Comparative Examples are shown in Table 1.

This application is based on Japanese Patent Application No. 2017-070197 filed on Mar. 31, 2017, the contents of which are incorporated herein by reference.

1: Raw water supply route (first raw water supply route, second raw water supply route)
2: Concentrated water discharge path (first concentrated water discharge path, second concentrated water discharge path)
3: Upstream permeate water or total permeate water extraction path 4: Downstream permeate water extraction path 5: Permeate water merge path 6: Raw water merge path (reflux path)
8: Concentrated water connection path 9: Permeate connection path 10: Downstream

permeate discharge paths

20a, 20b, 20c: Semipermeable membrane element 21: Semipermeable membrane module 22: Upstream semipermeable membrane module 23: Downstream semipermeable membrane Membrane module 24: Water collecting pipe 25: Water stop part or flow rate or flow path control part 26: Water collecting pipe separating part 27: Water collecting pipe valve 28: Permeate connection path switching part or permeate connection path valve 29: High pressure pump 30: Raw water 31: Concentrated water 32: Permeated water 40: Semipermeable membrane 41: Raw water channel material 42: Permeated water channel material

Claims

A fresh water generation method in which raw water is separated by a semipermeable membrane, concentrated water is discharged and permeate is taken out,
Concentrated water discharged from the preceding semipermeable membrane element is a semipermeable membrane element having a raw water supply port, a concentrated water discharge port, a semipermeable membrane, a raw water flow channel, a permeated water flow channel, and a water collecting pipe for collecting and taking out the permeated water. Including a semipermeable membrane module that is communicated via a water collecting pipe so as to be supplied as raw water to the latter semipermeable membrane element;
An upstream side semipermeable membrane module located on the upstream side in which m pieces of the semipermeable membrane elements (m is an integer of 2 or more) are connected, and p pieces of the semipermeable membrane elements (p is a natural number satisfying p <m). Downstream semipermeable membrane module that is connected to the downstream semipermeable membrane module, the first raw water supply path connected to the upstream semipermeable membrane module, and the upstream side concentration discharged from the upstream side semipermeable membrane module Concentrated water connection path connected to supply water as raw water to the downstream semipermeable membrane module, upstream permeated water obtained from the upstream semipermeable membrane module, and downstream obtained from the downstream semipermeable membrane module A permeate connection path connected to join the side permeate, a first concentrated water discharge path connected to the downstream semipermeable membrane module,
A first fresh water generator comprising a configuration in which the upstream semipermeable membrane module and the downstream semipermeable membrane module are connected via the concentrated water connecting route and the permeated water connecting route, or
The n semipermeable membrane elements (n is an integer of 3 or more) communicated, and between the downstream semipermeable membrane element less than n / 2 counted from the downstream side and the remaining upstream semipermeable membrane elements. A semipermeable membrane module provided with a water collecting pipe partitioning section or a water collecting pipe valve that provides resistance to the permeated water to the water collecting pipe located in the second water supply path, a second raw water supply path, a second concentrated water discharge path, and the downstream side semipermeable film A second structure including a downstream permeate extraction path for extracting the downstream permeate obtained from the membrane element, an upstream permeate or a total permeate extraction path for extracting the upstream permeate obtained from the upstream semipermeable membrane element; Use one of the water devices,
The total of the upstream permeable water obtained from the upstream semipermeable membrane module or the upstream semipermeable membrane element and the downstream permeable water obtained from the downstream semipermeable membrane module or the downstream semipermeable membrane element. A first operation method for extracting permeate and a second operation method for separating only the upstream permeate and dividing the upstream permeate to separate only the upstream permeate are arbitrarily switched. Water way.
A fresh water generation method using the first fresh water generator,
Using a fresh water generating device provided in the permeate connection path and having a permeate connection path switching unit capable of switching a flow path, and a downstream permeate discharge path connected to the permeate connection path switching unit,
The fresh water generation method according to claim 1, wherein the first operation method and the second operation method are arbitrarily switched by the permeate connection path switching unit.
A fresh water generation method using the first fresh water generator,
Using a fresh water generator provided with a permeate connection path valve provided in the permeate connection path and capable of switching between opening and closing,
The fresh water generation method according to claim 1, wherein the first operation method and the second operation method are arbitrarily switched by the permeate connection path valve.
A fresh water generation method using the second fresh water generator,
A fresh water generator comprising a flow rate or a flow path control unit for controlling a flow rate or a flow path provided in the downstream permeate take-out path in addition to the water collecting pipe partitioning part;
Or
In addition to the water collecting pipe valve, a fresh water generator comprising at least one of a water stop part provided in the downstream permeate water extraction path, or a flow rate or a flow path control part,
The fresh water generation method according to claim 1, wherein the first operation method and the second operation method are arbitrarily switched by the flow rate or the flow path control unit or the water collecting pipe valve.
In the fresh water generation method, about at least one selected from the group consisting of raw water, upstream concentrated water, concentrated water, upstream permeated water, downstream permeated water, total permeated water,
Measure at least one selected from the group consisting of water quality, water temperature, water volume, water pressure,
When the measured value is within a predetermined range, the first operation method is taken,
The fresh water generation method according to any one of claims 1 to 4, wherein the second operation method is taken when the measured value deviates from a predetermined range.
In the fresh water generation method,
If the ratio of the electrical conductivity of the downstream concentrated water to the electrical conductivity of the upstream concentrated water exceeds a predetermined value,
If the water quality of the downstream permeate or total permeate deteriorates beyond a predetermined value,
If the water temperature of raw water, upstream concentrated water, concentrated water, upstream permeated water, downstream permeated water, or total permeated water exceeds a predetermined value,
When the downstream permeate flow rate falls below a predetermined value,
Among the cases where the ratio of the downstream permeate flow rate to the upstream permeate flow rate falls below a predetermined value,
When at least one condition is met, the second driving method is taken,
The fresh water generation method according to any one of claims 1 to 5, wherein the first operation method is adopted when none of the conditions is satisfied.
The fresh water generation method according to any one of claims 1 to 6, wherein the raw water salt concentration is 30000 mg / L or more and the recovery rate is 30% or more.
A fresh water generator that separates raw water with a semipermeable membrane, discharges concentrated water, and extracts permeated water,
The semi-permeable membrane element (m is an integer of 2 or more) having a raw water supply port, a concentrated water discharge port, a semipermeable membrane, a raw water flow channel, a permeated water flow channel, and a collecting pipe for collecting and taking out permeated water An upstream semipermeable membrane module that is communicated via a water collection pipe so that the concentrated water discharged from the permeable membrane element is supplied as raw water to the subsequent semipermeable membrane element;
The p semipermeable membrane elements (p is a natural number satisfying p <m) are passed through a water collecting pipe so that the concentrated water discharged from the former semipermeable membrane element is supplied as raw water to the latter semipermeable membrane element. Including a downstream semipermeable membrane module in communication with each other,
A first raw water supply path connected to the upstream semipermeable membrane module is connected so that upstream concentrated water discharged from the upstream semipermeable membrane module is supplied as raw water to the downstream semipermeable membrane module. The concentrated water connection path, the permeate connection path connected to join the upstream permeate obtained from the upstream semipermeable membrane module and the downstream permeate obtained from the downstream semipermeable membrane module, the downstream side A first concentrated water discharge path connected to the semipermeable membrane module; a permeate connection path switching unit capable of switching the flow path; and a downstream permeate discharge path connected to the permeate connection path switching unit. A fresh water generator.
A fresh water generator that separates raw water with a semipermeable membrane, discharges concentrated water, and extracts permeated water,
The semi-permeable membrane element (m is an integer of 2 or more) having a raw water supply port, a concentrated water discharge port, a semipermeable membrane, a raw water flow channel, a permeated water flow channel, and a collecting pipe for collecting and taking out permeated water An upstream semipermeable membrane module that is communicated via a water collection pipe so that the concentrated water discharged from the permeable membrane element is supplied as raw water to the subsequent semipermeable membrane element;
The p semipermeable membrane elements (p is a natural number satisfying p <m) are passed through a water collecting pipe so that the concentrated water discharged from the former semipermeable membrane element is supplied as raw water to the latter semipermeable membrane element. Including a downstream semipermeable membrane module in communication with each other,
A first raw water supply path connected to the upstream semipermeable membrane module is connected so that upstream concentrated water discharged from the upstream semipermeable membrane module is supplied as raw water to the downstream semipermeable membrane module. The concentrated water connection path, the permeate connection path connected to join the upstream permeate obtained from the upstream semipermeable membrane module and the downstream permeate obtained from the downstream semipermeable membrane module, the downstream side The first concentrated water discharge path connected to the semipermeable membrane module, the total permeated water that is provided in a place different from the permeated water connection path or the upstream permeated water or the upstream permeated water and the downstream permeated water. An apparatus for producing fresh water, comprising: an upstream permeate or total permeate take-out path to be taken out; and a permeate connection path valve provided in the permeate connection path and capable of switching between opening and closing.
The concentrated water connection path;
The permeate connection path;
The permeate connection path valve;
Among the permeate connection paths, a path located between the downstream semipermeable membrane module and the permeate connection path valve,
The fresh water generator according to claim 9, which has pressure resistance capable of withstanding the operating pressure on the raw water side.
The fresh water generator according to any one of claims 8 to 10, wherein the number of the semipermeable membrane elements accommodated in the downstream semipermeable membrane module is one.
The fresh water generator according to claim 8, wherein the downstream permeated water discharge path and the first raw water supply path are connected via a raw water confluence path (reflux path).
A fresh water generator that has a high-pressure pump for boosting raw water, separates the raw water with a semipermeable membrane and discharges the concentrated water to take out the permeated water. The raw water supply port, the concentrated water discharge port, the semipermeable membrane, the raw water flow path, Concentrated water discharged from the semipermeable membrane element in the former stage is used as the semipermeable membrane element in the latter stage for n semipermeable membrane elements (n is an integer of 3 or more) having a permeate flow path and a water collecting pipe for collecting and taking out the permeated water. A semipermeable membrane module that is communicated via a water collecting pipe so as to be supplied as raw water, and the semipermeable membrane module includes a second raw water supply route, a second concentrated water discharge route, and the semipermeable membrane module. A downstream permeate extraction path for extracting downstream permeate obtained from less than n / 2 semipermeable membrane elements counting from the downstream side, and an upstream for extracting upstream permeate obtained from the remaining semipermeable membrane elements Side permeate or total permeate takeout With the road,
Provided in the water collection pipe delimiter for providing resistance to the permeate, provided in the water collection pipe on the upstream side of the semipermeable membrane element located at a position of less than n / 2 from the downstream side, and provided in the downstream permeate take-out path A flow rate or flow path control unit that controls the flow rate or flow path that is provided,
Or
In addition to the water collection pipe valve provided on the upstream side of the semipermeable membrane element at the position of less than n / 2 counting from the downstream side and capable of switching between opening and closing, it is provided in the downstream permeate extraction path. A fresh water generating device comprising at least one of a water stop portion or a flow rate or a flow path control portion.
The water collecting pipe separator or the water collecting valve,
Of the downstream permeated water extraction path, a path located between the semipermeable membrane module and the water stop or flow rate or flow path control unit,
The water stop part or flow rate or flow path control part is
14. The fresh water generator according to claim 13, which has pressure resistance capable of withstanding the operating pressure on the raw water side.
Of the n semipermeable membrane elements housed in the semipermeable membrane module, the water collecting tube partitioning portion or the water collecting tube valve is installed on the upstream side of the water collecting tube of the semipermeable membrane element located on the most downstream side. The fresh water generator according to claim 13 or 14, wherein the fresh water generator is provided.
The downstream permeated water extraction path and the second raw water supply path are connected to each other outside the semipermeable membrane module via the flow rate or flow path control unit and the raw water merging path (reflux path). The fresh water generator according to any one of claims 13 to 15, characterized in that: