WO2017064962A1

WO2017064962A1 - Water treatment device for boiler feed water and method for operating boiler

Info

Publication number: WO2017064962A1
Application number: PCT/JP2016/076824
Authority: WO
Inventors: 邦洋早川; 和義内田
Original assignee: 栗田工業株式会社
Priority date: 2015-10-14
Filing date: 2016-09-12
Publication date: 2017-04-20
Also published as: JP2017074550A; JP6631147B2; KR20180067529A; KR102613600B1

Abstract

Provided is a water treatment device for boiler feed water that can efficiently eliminate hard components and other impurities in raw water while suppressing energy consumption and increase boiler concentration rate. An RO membrane device 1 and water softener 2 are disposed in parallel and treated water is obtained by treating raw water with the RO membrane device 1 and/or the water softener 2; the treated water obtained is used as a boiler feed water. Thus, by the RO membrane 1 and water softener 2 being disposed in parallel, each performing processing, and the treated water from each being mixed, it is possible to obtain treated water that is cleaner than conventional treatment by water softener alone, thereby increasing the concentration rate of the boiler. By performing processing in parallel, it is possible to make each device smaller, thereby suppressing the energy consumed and the amount of waste water to a low level.

Description

Boiler feed water treatment apparatus and boiler operation method

The present invention relates to a water treatment apparatus and a water treatment method for treating water supplied to a boiler. The present invention also relates to a boiler operating method using the water treatment apparatus.

In the boiler system, impurities such as hardness components are removed from raw water such as city water, groundwater, and industrial water by water treatment equipment to produce boiler feed water. After the boiler treatment agent such as the agent is injected, it is supplied to the boiler.

As a water treatment device that removes impurities from raw water, using a softener that softens raw water (removal of hardness components) to make soft water, a filtration membrane such as a nanofiltration membrane or a reverse osmosis (RO) membrane, There are demineralizers that demineralize raw water and soft water, and deoxygenators that deoxygenate soft water and demineralized water.

Patent Document 1 describes that after softening treated water is desalted with a nanofiltration membrane, the desalted water is degassed to remove dissolved oxygen. Patent Document 2 describes that the raw water is desalted with an RO membrane and then deoxygenated.

JP 2005-288219 A Japanese Patent No. 3593723

The water softener cannot remove impurities other than the hardness component in the raw water, and cannot sufficiently reduce the conductivity and chloride ion concentration of boiler feed water. When the quality of the boiler feed water is poor, it is necessary to operate the boiler at a low concentration rate, which increases heat loss.

RO membrane equipment can remove not only hardness components but also other impurities such as corrosive components such as chloride ions and bicarbonate ions and dissolved organic matter, but it must be operated at high pressure and consumes a large amount of energy. .

When the raw water is treated with the water softener and then treated with the RO membrane device, the amount of water to be treated with the water softener is larger by the amount of concentrated water of the RO membrane device that is not used as boiler feed water. The frequency of playing is high.

The present invention provides a water treatment apparatus for boiler feed water and a treatment method capable of efficiently removing hardness components and other impurities in raw water while reducing energy consumption, thereby increasing the concentration rate of the boiler. For the purpose. Another object of the present invention is to provide a boiler operating method using this water treatment apparatus.

The present inventor has obtained the following knowledge.
RO membrane devices and water softeners are arranged in parallel to treat raw water, and by mixing the respective treated waters, cleaner treated water can be obtained compared to conventional water softener-only treatment, and boiler concentration The magnification can be increased.
By performing the treatment in parallel with the RO membrane device and the water softener, each device can be downsized, and the energy consumption and the amount of drainage can be kept small.
By adding a scale dispersant to the mixed treated water, it is possible to increase the concentration factor and to perform efficient operation while preventing troubles of scale and corrosion in the boiler can.
That is, the gist of the present invention is as follows.

[1] A water treatment device for boiler feed water that produces raw water by treating raw water with a reverse osmosis membrane device and / or a water softener, the reverse osmosis membrane device and the water softener arranged in parallel, and the reverse osmosis membrane device And the raw water supply pipe and the treated water discharge pipe connected to each of the water softeners, the treated water from the treated water discharge pipe of the reverse osmosis membrane device and the treated water from the treated water discharge pipe of the water softener As a boiler water supply apparatus, a water supply pipe for supplying water to a boiler is provided.

[2] In [1], the reverse osmosis membrane device is controlled by controlling the operating conditions of the reverse osmosis membrane device so that the ratio of the treated water amount of the reverse osmosis membrane device and the treated water amount of the water softener falls within a predetermined range. A boiler feed water treatment apparatus comprising operation control means for controlling the amount of treated water in a membrane device within a predetermined range.

[3] In [1], when the required water supply amount of the boiler is smaller than the treated water amount of the reverse osmosis membrane device, the raw water is supplied only to the reverse osmosis membrane device, and the required water supply amount of the boiler is the reverse osmosis amount A boiler water supply water treatment device, comprising raw water flow path switching means for supplying raw water to both the reverse osmosis membrane device and the water softener when the amount of treated water of the membrane device is exceeded.

[4] In any one of [1] to [3], the treated water amount of the reverse osmosis membrane device is equal to or less than the maximum required water supply amount of the boiler.

[5] In any one of [1] to [4], the boiler feed water has a scale dispersant addition means for adding a scale dispersant, and the scale dispersant contains acrylic acid as a polymerization or copolymerization component, A boiler comprising a polymer or copolymer containing at least one of methacrylic acid and maleic acid or a salt of the polymer or copolymer, the weight average molecular weight of which is 1,000 to 200,000 Water treatment equipment for water supply.

[6] In any one of [1] to [5], chemical addition means for adding boiler chemicals to the boiler feed water, conductivity measurement means for measuring the conductivity of the boiler feed water, and the conductivity measurement means A boiler feed water treatment apparatus, comprising: a chemical injection control means for controlling a chemical addition amount of the chemical addition means based on the electrical conductivity measured in (1).

[7] In any one of [1] to [5], a chemical addition unit for adding boiler chemicals to the boiler feed water, and a treated water amount measuring unit for measuring the respective treated water amounts of the reverse osmosis membrane device and the water softener And a chemical injection control means for controlling the chemical addition amount of the chemical addition means based on the ratio of the treated water quantity of the reverse osmosis membrane device measured by the treated water quantity measurement means and the treated water quantity of the water softener. A boiler water treatment apparatus characterized by the above.

[8] In any one of [1] to [7], a scale dispersant addition unit that adds a scale dispersant to the boiler feed water, a hardness measurement unit that measures the hardness of the boiler feed water, and the hardness measurement unit A boiler feed water treatment apparatus comprising: a chemical injection control unit that controls a scale dispersant addition amount of the scale dispersant addition unit based on the measured hardness.

[9] A boiler feed water treatment method for producing boiler feed water by treating raw water with a reverse osmosis membrane device and / or a water softener, wherein a part of the raw water is treated with a reverse osmosis membrane device and the remainder is treated with a water softener A water treatment method for boiler feed water, characterized in that the treated water of the reverse osmosis membrane device and the treated water of the water softener are fed to the boiler as boiler feed water.

[10] In [9], the reverse osmosis membrane device is controlled by controlling the operating conditions of the reverse osmosis membrane device so that the ratio of the treated water amount of the reverse osmosis membrane device and the treated water amount of the water softener falls within a predetermined range. A water treatment method for boiler feed water, wherein the amount of treated water in the membrane device is within a predetermined range.

[11] A boiler water treatment method for producing boiler feedwater by treating raw water with a reverse osmosis membrane device and / or a water softener, where the required water supply amount of the boiler is less than the treated water amount of the reverse osmosis membrane device If the raw water is treated only with the reverse osmosis membrane device and the treated water of the reverse osmosis membrane device is used as boiler feed water, and the required water supply amount of the boiler exceeds the treated water amount of the reverse osmosis membrane device, The boiler is treated with the reverse osmosis membrane device and the remainder is treated with the water softener, and the mixed water of the treated water of the reverse osmosis membrane device and the treated water of the water softener is used as boiler feed water. Water treatment method for water supply.

[12] The water treatment method for boiler feed water according to any one of [9] to [11], wherein the amount of treated water of the reverse osmosis membrane device is equal to or less than a maximum required water supply amount of the boiler.

[13] In any one of [9] to [12], a polymer or copolymer containing at least one of acrylic acid, methacrylic acid, and maleic acid as a scale dispersant or a polymerization or copolymerization component in the boiler feed water. A water treatment method for boiler feed water, comprising adding a polymer or a salt of the polymer or copolymer having a weight average molecular weight of 1,000 to 200,000.

[14] In any one of [9] to [13], the method for adding boiler chemicals to the boiler feedwater according to any one of claims 9 to 13, wherein the conductivity of the boiler feedwater is measured. Then, the boiler water supply method is characterized in that the amount of boiler chemical added is controlled based on the measured conductivity.

[15] The method according to any one of [9] to [13], wherein a boiler chemical is added to the boiler feed water, based on a ratio of a treated water amount of the reverse osmosis membrane device and a treated water amount of the water softener. A method for treating water for boiler feed water, comprising: controlling the amount of boiler chemical added.

[16] The method according to any one of [9] to [15], wherein a scale dispersant is added to the boiler feed water, the hardness of the boiler feed water is measured, and the scale dispersion is based on the measured hardness A water treatment method for boiler feed water, wherein the amount of the additive added is controlled.

[17] A boiler operating method, wherein the boiler feed water is manufactured by the boiler feed water treatment apparatus according to any one of [1] to [8], and the obtained boiler feed water is supplied to the boiler.

[18] A method for operating a boiler according to [17], wherein the electrical conductivity of water in the boiler can is measured, and the amount of blow water is controlled based on the measurement result.

According to the present invention, the following effects (i) to (iii) can be obtained.
(i) RO membrane device and water softener are arranged in parallel, raw water is treated with RO membrane device and / or water softener, and the treated water obtained is mixed into boiler feed water, so that only conventional water softeners are used. Thus, it is possible to obtain treated water that is cleaner than the above-described treatment, and to increase the boiler concentration rate.
(ii) By performing the treatment in parallel with the RO membrane device and the water softener, each device can be miniaturized, and the energy consumption and the amount of drainage can be kept small.
(iii) Since the RO membrane device and the water softener are arranged side by side, when one is stopped for regeneration, cleaning, maintenance, etc., it is possible to produce boiler feed water by processing on the other, so Water can be supplied.

It is a systematic diagram which shows an example of embodiment of the water treatment apparatus for boiler feed water of this invention. It is a graph which shows the time-dependent change of the required water supply amount of the boiler in Example 1.

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system diagram showing an example of an embodiment of a boiler feed water treatment apparatus according to the present invention. The RO membrane device 1 and the water softener 2 are installed in parallel. Raw water from the pipe 11 is supplied to the RO membrane device 1 and the water softener 2 through the

pipes

11A and 11B, respectively. The treated water of the RO membrane device 1 and the treated water of the water softener 2 are introduced into the water supply tank 3 via the

pipes

12A and 12B, respectively.

Treated water in the water supply tank 3 is supplied to the boiler 5 through a pipe 13 by the pump P ₁ as boiler feedwater. The pipe 13, chemicals chemical tank 4 by chemical feed pump P _2, is injected via a pipe 14. Reference numeral 15 denotes a blow pipe having a blow valve 15a.

* Steam condensate from the boiler 5 may be returned to the water supply tank 3.

On-off

valves

11a and 11b are provided on a pipe 11A for supplying raw water to the RO membrane device 1 and a pipe 11B for supplying raw water to the water softener 2, respectively. The treated water discharge pipe 12A from the RO membrane device 1 and the treated water discharge pipe 12B from the water softener 2 are provided with flow meters F _a and F _b , respectively. The measured values of the flow meters F _a and F _b are input to the control device 10. The pipe 12A, the conductivity meter _{C 1} is provided. Measurements of the conductivity meter C ₁ is input to the control unit 10.

The water supply pipe 13 from the water supply tank 3 to the boiler 5 durometer C ₂ and the flowmeter F _c is provided. Measurement of hardness tester C ₂ and the flowmeter F _c is inputted to the control unit 10.

The boiler 5 is provided with a conductivity meter (not shown) for measuring the conductivity of water in the boiler can. A measured value of the conductivity meter is input to a control device (not shown), and an open / close signal of the blow valve 15a is output from the control device based on the measured value.

The following (1) and (2) operating methods are mentioned as a method for producing boiler feedwater using such a boiler feedwater treatment apparatus.

(1) A part of the raw water is treated with the RO membrane device 1, the remaining part is treated with the water softener 2, and the mixed water of these treated water is used as boiler feed water.
According to this method, the following effects can be obtained.
In the water softener 2, although Ca hardness can be made substantially zero, corrosive components such as chloride ions and bicarbonate ions cannot be removed. The RO membrane device 1 can remove other impurities such as corrosive components such as chloride ions and bicarbonate ions and dissolved organic matter, but a slight amount of Ca hardness leaks. By always using the water softener 2 and the RO membrane device 1 at all times, corrosion components such as Ca hardness, chloride ions, bicarbonate ions, and the like in the boiler feed water can be reduced or adjusted in a balanced manner. As a result, the required amount of boiler chemicals can be reduced.

(2) When the operational status (load) of the boiler is low and the required amount of water supply is small, only the RO membrane device 1 is treated and the treated water of the RO membrane device 1 is used as boiler feedwater, and the boiler operational status (load) is When the required water supply amount is higher than the amount of treated water (processing capacity) of the RO membrane device, the water softener 2 is used together, and the amount of treated water that cannot be supplied by the RO membrane device 1 is covered by the treated water of the water softener 2. .
According to this method, the following effects can be obtained.
While operating with only the RO membrane device 1, when the boiler required water supply amount exceeds the treated water amount of the RO membrane device 1, the average water quality of the boiler water supply can be obtained by using the water softener 2 as an auxiliary. It is possible to increase the concentration rate of the boiler as good and to reduce the amount of blow water.
Since the water softener 2 is used auxiliary, the amount of ion exchange resin in the water softener 2 can be reduced, and the regeneration frequency can also be reduced.

In both cases (1) and (2), it is not necessary to use an RO membrane device corresponding to the maximum required water supply amount of the boiler, and the RO membrane device can be downsized.

In both cases (1) and (2), the RO membrane device has a maximum required water supply amount of the boiler to be supplied (the water supply amount required at the maximum load of the boiler), for example, the maximum required water supply amount of the boiler. A treated water amount of about 10 to 90% is used, and a water softener having a treated water amount of 10 to 90% of the required water supply amount of the boiler can be used so that the shortage can be replenished. By doing in this way, each of a RO membrane apparatus and a water softener can be reduced in size.

The operation method of (1) is specifically as follows.
Both the on-off

valves

11a and 11b are opened, and raw water is supplied to the RO membrane device 1 and the water softener 2 through the

pipes

11, 11A and 11B, respectively. The treated water of the RO membrane device 1 and the water softener 2 is supplied to the water supply tank 3 through the

pipes

12A and 12B, and the mixed water of the treated water of the RO membrane device 1 and the treated water of the water softener 2 in the water supply tank 3 is pumped P ₁ is fed to the boiler 5 via the pipe 13. The pipe 13 scale dispersant described below from chemical tank 4 is added via alkaline modifier, a pipe 14 from the pump P ₂ chemicals for boilers, such as condensate treatment agent.

In this operation method, the mixing ratio of the treated water of the RO membrane device 1 and the treated water of the water softener 2 is not particularly limited, but by making the mixing ratio constant, the quality of the boiler feed water is substantially constant, The amount of chemicals added can be made constant. However, in the RO membrane device 1, by continuing the operation, the amount of treated water may decrease due to membrane blockage, and the mixing ratio may vary. For this reason, the control device 10 outputs a control signal for the operating conditions of the RO membrane device 1, controls the water supply pressure of the RO membrane device 1, etc., and maintains the amount of treated water in the RO membrane device 1 to keep the mixing ratio constant. You may make it.

As long as the mixing ratio is constant, the amount of boiler chemical added may be a constant amount. When the mixing ratio varies, when the quality of boiler feed water varies due to drain recovery, or when the quality of treated water in the RO membrane device 1 varies, it is preferable to control the chemical injection amount according to the variation. In that case, it is preferable to control the blow amount together. This control is preferably performed based on measured values such as the conductivity and pH of boiler feed water, boiler feed water hardness, boiler feed water flow rate, and the like. In Figure 1, the measured value of the hardness tester C ₂ and the flowmeter F _c of the conductivity meter C ₁ and flowmeter F _a and pipe 13 of the pipe 12A is input to the control unit 10, based on the measurement value, chemical feeding, chemical dosing and controls the operation of the pump P _2, it is possible to control the chemical amount. Specifically, a method of proportionally controlling the amount of chemical added according to the measured value of conductivity, and a method of controlling the amount of added scale dispersant according to the measured value of hardness when adding a scale dispersant. . Install a hardness tester C ₂ to the discharge pipe 12A of RO treated water, with respect to the value of the flow meter F _a, it is also possible to add a scale dispersant required.

When the mixing ratio of the treated water of the RO membrane device 1 and the treated water of the water softener 2 varies, the mixing ratio can be obtained and the chemical addition amount can be controlled by calculation. In the boiler feed water treatment apparatus of FIG. 1, the measured values of the flow meters F _a and F _b provided in the treated water discharge pipe 12A of the RO membrane device 1 and the treated water discharge pipe 12B of the water softener 2 are transferred to the control device 10, respectively. is inputted, it calculates the mixing ratio on the basis of this value, so that the drug amount in accordance with the mixing ratio, it is also possible to control the chemical feed pump P _2.

The operation method of (2) is specifically as follows.
The required water supply amount of the boiler 5 is input to the control device 10 from the operation status of the boiler 5. When the required water supply amount is equal to or less than the treated water amount (processing capacity) of the RO membrane device 1, only the on-off valve 11a is opened, the on-off valve 11b is closed, and raw water is supplied to the RO membrane device 1 through the pipes 11 and 11A. the treated water of the RO membrane apparatus 1 feeds sent to the water supply tank 3 from the pipe 12A, which delivers the water in the water supply tank 3 to the boiler 5 through a pipe 13 by the pump P _1.

When the required water supply amount of the boiler 5 exceeds the treated water amount (treatment capacity) of the RO membrane device, the signal from the control device 10 is used to turn on / off

valves

11a and 11b in the same manner as in the operation method (1). Both are opened, and raw water is supplied to the RO membrane device 1 and the water softener 2 through the

pipes

11, 11A, and 11B, respectively. and it is fed to the boiler 5 through a pipe 13 to the mixing water of the RO membrane treated water apparatus 1 and the water softener 2 of treated water in the water supply tank 3 by a pump P _1. In this case, the water softener 2 controls the opening degree of the on-off valve 11b with a signal from the control device 10 so as to supply the amount of treated water that cannot be supplied by the RO membrane device 1.

Instead of the on-off valve, a flow path can be switched by providing a three-way valve at the branch portion of the pipe 11 and the

pipes

11A and 11B.

In the case of the operation method (2), during the period when only the treated water of the RO membrane device 1 is used as boiler feed, impurities such as corrosive components such as chloride ions and bicarbonate ions are removed. Treated water containing hardness will be supplied as boiler feed water. For this reason, in a boiler, although there is almost no problem of corrosion, a problem of scale generation may occur. When the mixed water of the treated water of the RO membrane device 1 and the water softener 2 is boiler feed water, the Ca hardness of the boiler feed water is reduced, but the corrosion component is slightly increased.

Even in the case of (1), depending on the mixing ratio of the treated water of the RO membrane device 1 and the treated water of the water softener 2, the scale tends to be a problem when the treated water of the RO membrane device 1 is large. When the amount of treated water in the vessel 2 is large, corrosion tends to be a problem.

By controlling the amount of boiler chemicals such as scale dispersants and anticorrosives according to the operating status of RO membrane device 1 and water softener 2 (the ratio of treated water, operating time, etc.) It becomes possible to continue operation stably. When the scale dispersant or the anticorrosive is a single agent, it is desirable to control the blending ratio in the control device 10. The boiler chemicals such as the scale dispersant will be described later.

Examples of raw water to be treated in the present invention include city water, ground water, industrial water and the like. The raw water is preferably supplied to the RO membrane device 1 or the water softener 2 after being turbidized by a microfiltration membrane or the like. The boiler feed water treatment device of the present invention may have a turbidity removal device on the upstream side of the pipe 11.

The material and shape of the RO membrane of the RO membrane device are not particularly limited, but an RO membrane made of aromatic polyamide is preferably used. Examples of the shape include a flat membrane, a spiral, a hollow fiber, and a tubular, and a spiral RO membrane is preferably used.

In the RO membrane apparatus, when there is a risk of scale deposition, it is preferable to operate while preventing scale deposition by applying a known scale dispersant or adjusting pH. There is no restriction | limiting in particular in the scale dispersing agent for RO membranes, A well-known agent can be used. In the RO membrane device, when there is a risk of slime breeding, stabilization can be achieved by using a slime control agent, a bactericidal agent, a bacteriostatic agent and the like. There is no restriction | limiting in particular also in the chemical | medical agent in this case, A well-known agent can be used.

A water softener generally refers to a Na-type cation exchange resin tower.

The scale dispersant added to the boiler feed water is a polymer (homopolymer) or copolymer (copolymer) containing at least one of acrylic acid, methacrylic acid and maleic acid as a polymerization or copolymerization component, or the polymer or copolymer. It is preferred to use a polymer salt.

Specifically, examples of the homopolymer include polyacrylic acid, polymethacrylic acid, and polymaleic acid.

Examples of the copolymer include one or more of acrylic acid, methacrylic acid and maleic acid, conjugated diene sulfonic acid such as 2-methyl-1,3-butadiene-1-sulfonic acid, and 3-allyloxy-2-hydroxypropane. Unsaturated (meth) allyl ether monomers having a sulfo group such as sulfonic acid, 3-methallyloxy-2-hydroxypropanesulfonic acid, (meth) acrylamide-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamide Propanesulfonic acid, styrenesulfonic acid, methallylsulfonic acid, vinylsulfonic acid, allylsulfonic acid, isoamylenesulfonic acid, compounds having a sulfo group such as salts thereof, isobutylene, amylene, acrylamide, N-vinylformaldehyde, etc. The non-ionic compound of Kuroto Acid, isocrotonic acid, vinyl acetate, atropic acid, fumaric acid, itaconic acid, a copolymer of one or more selected from a compound having a carboxyl group, such as hydroxyethyl acrylate or salts thereof.

Examples of salts of these homopolymers and copolymers include sodium salts, potassium salts, and ammonium salts.

The weight average molecular weight (according to the GPC method (SEC method)) of these polymers, copolymers, or salts thereof is 1,000 to 200,000, particularly 10,000 to 100,000, especially 20,000 to 70,000. preferable. If the weight average molecular weight is less than 1,000, a sufficient scale preventing effect may not be obtained. When the weight average molecular weight exceeds 200,000, the scale prevention effect decreases.

Only one type of scale dispersant may be added, or two or more types may be added in combination. The scale dispersant may be used in combination with other scale dispersants. Other scale dispersants include, for example, various phosphates, polymers or copolymers having a low weight average molecular weight that do not satisfy the above-mentioned conditions among the above-described scale dispersants, and water-soluble polymer compounds such as sodium salts thereof. Phosphonates, chelating agents and the like.

The amount of the scale dispersant comprising these polymers, copolymers, or salts thereof is preferably such that the concentration in the boiler water is 10 to 500 mg / L, and the concentration in the boiler water is 20 to It is more preferably 400 mg / L, further preferably 30 to 300 mg / L, particularly preferably 50 to 250 mg / L. By setting the concentration in the boiler water to 10 mg / L or more, a sufficient scale dispersion effect is easily exhibited. By making the density | concentration in boiler water 500 mg / L or less, the cost effectiveness can be made favorable, preventing the complexity of the waste water treatment by the raise of COD.

The scale dispersant is preferably added to makeup water or water supply. When a boiler is a circulation type, you may add to condensate.

In the present invention, as long as the purpose of the present invention is not impaired, various additive components such as oxygen scavengers and anticorrosives are used for boilers at any point in the boiler equipment as necessary. Chemicals may be added.

The boiler feed water treatment apparatus of the present invention may further include a deoxygenation apparatus downstream of these apparatuses in addition to the RO membrane apparatus and water softener shown in FIG. It is also possible to operate the RO membrane device as an aid to the water softener.

Hereinafter, the present invention will be described more specifically with reference to examples.

In the following, the following were used as the RO membrane device and water softener.

<RO membrane device>
RO membrane: Nitto Denko's 8-inch RO membrane “ES20-D8”
Treated water volume: 4m ³ / h
<Water softener>
Ion exchange resin: Na type anion exchange resin Treated water amount: 4 m ³ / h

[Example 1]
In a boiler system with a required water supply amount of 8 m ³ / h at the maximum load of the boiler, as shown above, the water softener and the RO membrane device having a treatment capacity of 50% of the required water supply amount are arranged in parallel as shown in FIG. (Isui) was processed.

In the fluctuation of the required water supply amount accompanying the boiler load fluctuation as shown in Fig. 2, the RO membrane device is preferentially operated (operation in which raw water is processed only by the RO membrane device), and the processing capability of the RO membrane device is increased. When it exceeded, the operation which obtains the boiler water for that from a water softener was performed.

In FIG. 2, the part with dots is the boiler water supply with the treated water of the RO membrane device, and the part with the hatches is the boiler water supply with the treated water of the water softener.

In the boiler feed water, polyacrylate having a weight average molecular weight of 70,000 was constantly added at 10 mg / L. With this chemical addition, the polyacrylic acid concentration in the boiler water becomes 100 to 150 mg / L.

With this system, the amount of blown water was reduced by 50% compared to a water supply system using only a water softener. Since the water softener was an auxiliary operation, the resin capacity could be reduced by 30% compared to the water supply system only with the water softener, and the regeneration frequency of the water softener could be reduced by 50%.

[Example 2]
In Example 1, the injection amount of boiler chemicals was controlled according to the operation time of the water softener. Specifically, only when the water softener is not operated, the amount of polyacrylate added to the boiler feed water is 10 mg / L. When the water softener is operated, the amount of chemical added according to the amount of water treated by the water softener Was reduced by 2-4 mg / L to 6-8 mg / L. As a result, the necessary amount of polyacrylate was reduced, scale adhesion was prevented even during long-term operation, and stable operation was possible.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2015-203026 filed on Oct. 14, 2015, which is incorporated by reference in its entirety.

DESCRIPTION OF SYMBOLS 1 RO membrane apparatus 2 Water softener 3 Water supply tank 4 Chemical tank 5 Boiler 10 Control apparatus

Claims

A boiler water treatment device for producing boiler feed water by treating raw water with a reverse osmosis membrane device and / or a water softener,
A reverse osmosis membrane device and a water softener arranged in parallel;
Raw water supply piping and treated water discharge piping connected to each of the reverse osmosis membrane device and the water softener;
A boiler water treatment apparatus, comprising: treated water from a treated water discharge pipe of the reverse osmosis membrane device; and a feed water pipe for supplying treated water from the treated water discharge pipe of the water softener to a boiler as boiler feed water .
2. The reverse osmosis membrane device according to claim 1, wherein the reverse osmosis membrane device operating conditions are controlled so that the ratio of the treated water amount of the reverse osmosis membrane device and the treated water amount of the water softener is within a predetermined range. A boiler water treatment apparatus having operation control means for controlling the amount of treated water within a predetermined range.
In Claim 1, when the required water supply amount of the boiler is smaller than the treated water amount of the reverse osmosis membrane device, the raw water is supplied only to the reverse osmosis membrane device, and the required water supply amount of the boiler is equal to that of the reverse osmosis membrane device. When the amount of treated water is exceeded, the boiler water supply device is provided with raw water flow path switching means for supplying raw water to both the reverse osmosis membrane device and the water softener.
4. The boiler feed water treatment apparatus according to any one of claims 1 to 3, wherein the amount of treated water of the reverse osmosis membrane device is equal to or less than a maximum required water supply amount of the boiler.
The scale dispersant adding means for adding a scale dispersant to the boiler feed water according to any one of claims 1 to 4, wherein the scale dispersant includes acrylic acid, methacrylic acid and a polymerization or copolymerization component. A water treatment for boiler feed water, which is a polymer or copolymer containing at least one maleic acid or a salt of the polymer or copolymer, the weight average molecular weight of which is 1,000 to 200,000 apparatus.
6. The method according to any one of claims 1 to 5, wherein a chemical addition means for adding boiler chemicals to the boiler feed water, a conductivity measurement means for measuring the conductivity of the boiler feed water, and the conductivity measurement means. And a chemical injection control means for controlling the chemical addition amount of the chemical addition means based on the electrical conductivity.
In any one of Claims 1 thru | or 5, The chemical | medical agent addition means to add the chemical | medical agent for boilers to the said boiler feed water, The treated water amount measuring means to measure each treated water quantity of the said reverse osmosis membrane apparatus and a water softener, It has a chemical injection control means for controlling the chemical addition amount of the chemical addition means based on the ratio of the treated water quantity of the reverse osmosis membrane device measured by the treated water quantity measurement means and the treated water quantity of the water softener. Boiler feed water treatment equipment.
In any 1 item | term of Claim 1 thru | or 7, it measured with the scale dispersing agent addition means which adds a scale dispersing agent to the said boiler feed water, the hardness measurement means which measures the hardness of this boiler feed water, and this hardness measurement means A boiler feed water treatment apparatus comprising: a chemical injection control unit that controls a scale dispersant addition amount of the scale dispersant addition unit based on hardness.
A boiler feed water treatment method for producing boiler feed water by treating raw water with a reverse osmosis membrane device and / or a water softener,
A part of raw water is treated with a reverse osmosis membrane device and the remainder is treated with a water softener, and the mixed water of the treated water of the reverse osmosis membrane device and the treated water of the water softener is supplied to the boiler as boiler feed water. A boiler water supply method characterized by the above.
10. The reverse osmosis membrane device according to claim 9, wherein operating conditions of the reverse osmosis membrane device are controlled so that a ratio of a treated water amount of the reverse osmosis membrane device and a treated water amount of the water softener is within a predetermined range. A water supply method for boiler feed water, characterized in that the amount of treated water is within a predetermined range.
A boiler feed water treatment method for producing boiler feed water by treating raw water with a reverse osmosis membrane device and / or a water softener,
When the required water supply amount of the boiler is smaller than the treated water amount of the reverse osmosis membrane device, the raw water is treated only with the reverse osmosis membrane device and the treated water of the reverse osmosis membrane device is used as boiler feed water,
When the required water supply amount of the boiler exceeds the treated water amount of the reverse osmosis membrane device, a part of the raw water is treated with the reverse osmosis membrane device and the remainder is treated with the water softener, and the treated water of the reverse osmosis membrane device is treated. A water supply method for boiler feed water, wherein mixed water of the water and the treated water of the water softener is used as boiler feed water.
12. The boiler feed water treatment method according to any one of claims 9 to 11, wherein the amount of treated water of the reverse osmosis membrane device is equal to or less than a maximum required water supply amount of the boiler.
The polymer or copolymer according to any one of claims 9 to 12, wherein the boiler feed water contains at least one of acrylic acid, methacrylic acid and maleic acid as a polymerization or copolymerization component as a scale dispersant. A water treatment method for boiler feed water, comprising adding a salt of a polymer or copolymer having a weight average molecular weight of 1,000 to 200,000.
14. The method according to any one of claims 9 to 13, wherein a boiler chemical is added to the boiler feed water, the conductivity of the boiler feed water is measured, and the boiler chemical is measured based on the measured conductivity. The water supply method for boiler feed water characterized by controlling the addition amount.
The method for adding boiler chemicals to the boiler feed water according to any one of claims 9 to 13, wherein the boiler is based on a ratio of a treated water amount of the reverse osmosis membrane device and a treated water amount of a water softener. A method for treating water for boiler feed water, comprising controlling the amount of chemicals added.
The method according to any one of claims 9 to 15, wherein a scale dispersant is added to the boiler feedwater, the hardness of the boiler feedwater is measured, and the scale dispersant is added based on the measured hardness. A water supply method for boiler feed water, wherein the amount is controlled.
9. A boiler operating method, wherein boiler supply water is manufactured by the boiler water supply device according to any one of claims 1 to 8, and the obtained boiler supply water is supplied to the boiler.
18. The method of operating a boiler according to claim 17, wherein the electrical conductivity of water in the boiler can is measured, and the amount of blow water is controlled based on the measurement result.