TW201901084A - Boiler water treatment apparatus and treatment method - Google Patents

Abstract

Industrial water is supplied via a pretreatment device 1 and a pure water tank 3 to a boiler of an electric power generating apparatus 6. Boiler blowdown water is demineralized by a condensate demineralizing apparatus 10 and returned to the pure water tank 3. A portion of the pure water in the pure water tank 3 is supplied to an RO device 18 and the RO permeate is returned to the pure water tank 3. The RO concentrate is conveyed via piping 20 to a first heat exchanger 8B.

Description

Boiler water treatment device and treatment method

The present invention relates to an apparatus and method for treating boiler water of a power generation facility such as a company using a fire power, an IPP power generation facility, or an industrial thermal power generation facility.

In the industrial complex, the implementation of IPP power generation (independent power generation business) is widely expanded. In power generation equipment such as IPP, pure water is produced by pretreatment (coagulation solid-liquid separation and dechlorination treatment, etc.) from industrial water, etc., and pure water is used to generate steam by a high-pressure boiler. Power generation. In the power generation facility, the boiler overflow water is recovered, and after the dechlorination treatment, it is reused as pure water for power generation (Patent Documents 1 to 3).

In the power generation facility, the water quality of the boiler water is managed. In particular, in order to prevent corrosion, the electrical conductivity of the boiler water treated by the ion exchange resin is managed. When the original water is included in the raw water (for example, the TOC is 200 ppb or more), or when the organic substance is excessively dissolved from the ion exchange resin in the pretreatment pure water production, the electric conduction of the boiler water The degree will exceed the management value.

[Patent Document 1] Japanese Laid-Open Patent Publication No. JP-A-2010-216913 (Patent Document 3)

[Non-Patent Document 1] Heisei 14th Edition Boiler Yearbook, "Section 9: Raw water in supplementary boilers, the quality of supplementary water and its influence on boiler water quality and its countermeasures"

An object of the present invention is to provide a boiler water treatment apparatus and a treatment method capable of stably supplying high-quality pure water to a boiler even when the TOC of the raw water or the pre-treated water is at a high concentration.

The boiler water treatment device according to the present invention includes: a pretreatment device that processes raw water to produce pure water; and a pure water supply line that supplies pure water from the pretreatment device to the boiler In the boiler water treatment device, the TOC removal line is provided, and one part of the pure water is taken out from the take-out portion from the pure water supply line, and the TOC removal process is performed by the TOC removal means. And returning the treated water to the take-out portion or the pure water supply line on the more upstream side.

In one aspect of the invention, the take-up portion is disposed at a pure water tank of the pure water supply line.

In one aspect of the invention, the TOC removal means includes an RO device or a UV oxidation device and an ion exchange device.

A boiler water treatment device according to one aspect of the present invention is characterized by: a method for measuring a TOC concentration of pure water in a pure water take-out portion or a pure water supply line on an upstream side thereof; and When the measured value is equal to or greater than a specific value, the removal of the TOC by the TOC removing means or the pure water supply amount controlling means for increasing the amount of pure water supplied to the TOC removing means is started.

A boiler water treatment apparatus according to one aspect of the present invention is provided with a recirculating water dechlorination means for dechlorinating a boiler overflow water which condenses exhaust gas from the boiler and is discharged from the boiler; And introducing the boiler overflow water from the boiler into the boiler overflow water introduction line in the double-flow water dechlorination means; and removing the chlorine-removing water from the re-flowing water which is subjected to the dechlorination treatment by the re-flowing water dechlorination means The recirculating water dechlorination water return line to the aforementioned take-out portion or the pure water supply line at the upstream side thereof.

A boiler water treatment device according to one aspect of the present invention includes an RO device as the TOC removal means, and the boiler overflow water introduction line is provided with RO concentrated water and boiler overflow water of the RO device. Heat exchanger for heat exchange.

In the boiler water treatment method of the present invention, the raw water is treated by a front device to produce pure water, and the pure water from the pretreatment device is supplied to the boiler via a pure water supply line. The boiler water treatment method is characterized in that a part of pure water is taken out from the take-out portion from the pure water supply line, and TOC removal processing is performed by TOC removal means, and the treated water is returned to the take-out portion or It is at this pure water supply line on the upstream side.

In the boiler water treatment method according to one aspect of the present invention, the TOC removal means includes an RO device or a UV oxidation device and an ion exchange device.

In a boiler water treatment method according to an aspect of the present invention, the TOC concentration of the pure water of the pure water supply line of the take-out portion or the upstream side thereof is measured, and when the measured value is a specific value or more At the time, the removal of the TOC by the TOC removal means or the increase of the supply amount of the pure water for the TOC removal means is started.

In a boiler water treatment method of one aspect of the present invention, a boiler overflow water which condenses exhaust gas from the boiler and is discharged from the boiler is dechlorinated by means of a reflow dechlorination means. And the dechlorination water of the dechlorination treatment by the dechlorination means is returned to the above-mentioned take-out portion or to the pure water supply line on the upstream side thereof.

In a boiler water treatment method according to one aspect of the present invention, the TOC removal means is provided with an RO device for causing the RO concentrated water of the RO device to be supplied to the boiler overflow water supplied to the reflowing water dechlorination means. Heat exchange and cool the boiler overflow water. [Effects of the Invention]

In the present invention, the TOC removing means is not provided in the pure water supply line (main line) for supplying the pure water from the pretreatment apparatus to the boiler, but is different from the pure water supply line. The TOC removal means is set at the TOC removal line (offline). Therefore, it is possible to control the TOC removal means independently of the pure water supply control at the pure water supply line (main line).

For example, in the present invention, when the TOC load of the raw water is low, the TOC removal operation can be temporarily interrupted. Moreover, even when the pure water supply line is performing the pure water supply operation, the maintenance of the TOC removal means can be performed.

In one aspect of the invention, it is possible to suppress the influence of the resin elution caused by the chlorine removal means of the boiler overflow water.

In one aspect of the invention, the RO concentrated water system of the TOC removal line is used as cooling water for the boiler overflow water.

Hereinafter, the embodiment will be described with reference to the drawings.

Fig. 1 is a flow chart showing a boiler water treatment apparatus according to a first embodiment. The raw water (industrial water) is pretreated by the pretreatment apparatus 1 and becomes pure water, and is introduced into the pure water tank 3 (corresponding to the take-out portion) via the pipe 2. The pure water in the pure water tank 3 is supplied to a boiler of the power generating device 6 such as an IPP power generation device via a pipe 5 having a pump 4 .

In this embodiment, the pure water supply line includes a pipe 2, a pure water tank 3, a pump 4, and a pipe 5. The boiler overflow water generated in the boiler of the power generation device 6 is introduced into the double-flow water removal device 10 via the introduction line including the piping 7, the first heat exchanger 8B, the cooling means 8A, and the piping 9. It is subjected to dechlorination treatment.

In this embodiment, the double-flow water removal device 10 is provided with reverse osmosis membrane separation devices (RO devices) 11, 12 arranged in series (in this embodiment, two stages). And an electrical chlorine removal device 13. The boiler overflow water is dechlorinated by RO treatment and electrical dechlorination treatment, and becomes pure water, and is sent back and forth to the pure water tank 3 via the pipe 14.

In order to take out a part of the pure water in the pure water tank 3 and perform TOC removal treatment and dechlorination treatment, a TOC removal line is provided. The pure water in the pure water tank 3 is supplied to the RO unit 18 via the piping 15, the second heat exchanger 16, and the pump 17, and the RO dialyzing water is returned to the pure water tank 3 via the piping 19. The RO concentrated water is sent to the first heat exchanger 8B via the pipe 20, exchanges heat with the boiler overflow water, and is then returned to the pretreatment apparatus 1 or the upstream side via the piping 21. Raw water piping or raw water tank, or discharged to the outside.

The second heat exchanger 16 heats the pure water supplied from the pure water tank 3 to the RO unit 18.

The first heat exchanger 8B cools and cools the boiler overflow water which is sent to the reflow water removal device 10 at the water. At the low temperature fluid side of the first heat exchanger 8B, the water is supplied with concentrated water from the RO unit 18.

In the boiler water treatment apparatus, the water of the pure water in the pure water tank 3 can be maintained by operating the pump 17 as necessary and performing the RO treatment by the pure water in the pure water tank 3 via the RO unit 18. Within a certain range.

By heating the pure water supplied to the RO unit 18 by the second heat exchanger 16, the RO treatment efficiency can be improved. By flowing the RO dialysis water having a high temperature into the pure water tank 3, the water temperature in the pure water tank 3 becomes high.

In Fig. 1, the pipe 15 is connected to the pure water tank 3 as a take-out portion. However, the pipe 15 may be connected to the pipe 5 on the downstream side of the pure water tank 3. In this case, the divergence point is the take-out portion.

In FIG. 1, the first heat exchanger 8B may be omitted, and the boiler overflow water may be cooled to a specific temperature only by the cooling means 8A without preliminary cooling.

Fig. 2 is a flow chart showing a boiler water treatment apparatus according to a second embodiment. The TOC removal device for maintaining the water quality of the pure water in the pure water tank 3 is provided with a UV (ultraviolet) oxidation device 25 and an ion exchange device 26 instead of the RO device 18 in Fig. 1 .

As the ion exchange resin, an anion exchange resin or a mixed bed resin is preferred. In a UV oxidizing device (for example, a low-pressure UV oxidizing device) 25, UV is irradiated to the water to be treated (pure water from the pure water tank 3) and the organic matter is decomposed into an organic acid and further decomposed into CO ₂ . The organic acid, CO ₂ or the like resulting from the decomposition is removed by the ion exchange device 26 in the subsequent stage. The pure water having a low organic matter concentration after passing through the ion exchange unit 26 is returned from the pipe 19 to the pure water tank 3.

In this embodiment, since the RO device 18 is not provided, the pipes 20 and 21 for supplying the RO concentrated water to the first heat exchanger 8B are not provided. At the low-temperature fluid side of the first heat exchanger 8B, there is a cooling water introduced from the outside of the water.

The boiler overflow water from the boiler of the power generation device 6 is sent to the double-flow water removal device 10 via the introduction line including the pipe 7, the first heat exchanger 8B, the cooling means 8A, and the pipe 9. The other components are the same as in FIG. 1, and the same component symbols represent the same parts.

In FIG. 2, the first heat exchanger 8B may be omitted, and the boiler overflow water may be cooled to a specific temperature only by the cooling means 8A without preliminary cooling.

1 and 2 are examples of the present invention, and the present invention may be other than the drawings.

Hereinafter, suitable examples, functions, and the like of the constituent devices of the boiler water treatment apparatus of Figs. 1 and 2 will be described.

1) Pre-treatment unit 1 The pre-processing unit 1 is, for example, condensing treatment or solid-liquid separation (precipitation separation or pressurized floating separation, etc.) for raw water such as industrial water (urban water, groundwater, etc.). , double-layer filtration, followed by dechlorination treatment (process by cation exchange resin column, decarbonation column, anion exchange resin column, mixed bed resin column, electric dechlorination device, etc.), thereby manufacturing Pure water.

2) Pure water tank 3 In the pure water tank 3, the pure water produced by the pretreatment is stored, and the water quality and the water quantity are adjusted.

3) TOC removal means When the concentration of TOC contained in raw water such as industrial water is high, there is a possibility that it is difficult to reduce the TOC concentration to a specific value (for example, less than 100 ppb) by pretreatment. Case. If the TOC concentration is 100 ppb or more, the burden on the boiler will increase, and there will be a failure in the future. Further, depending on the season or climate, the water temperature may vary (for example, 5 to 35 ° C). When the water temperature is 15° C. or less, the burden on the boiler for power generation is increased, and the amount of fuel used is increased.

Therefore, the pure water which is separated from the pure water tank 3 constituting the pure water supply line is maintained so that the TOC of the pure water in the pure water tank 3 is constantly maintained at a specific value or less (for example, 100 ppb or less). The TOC removal process is performed by the RO device 18 or the TOC removal means constituted by the UV oxidation device 25 and the ion exchange device 26.

By using a physicochemical means as a TOC removing means, it is possible to suppress the case where impurities remain in the treated water. By setting the TOC removal means at the TOC removal line branched from the pure water supply line, it is possible to carry out the pure water supply line, for example, without being affected by the stoppage of water caused by the backwashing of the membrane. Different control or repair. The TOC removal means can be easily installed at the boiler water supply unit that has been set up by additional work.

It is also possible to provide a pure water take-out portion (pure water tank 3 in FIGS. 1 and 2) or a pure water supply line on the upstream side of the TOC removal treatment by the TOC removal means (in FIG. 1). In the second, the TOC concentration measuring means of the TOC concentration of the pure water of the pipe 2) is used, and when the measured value of the TOC concentration measuring means is a specific value or more, the TOC removal process by the TOC removing means is started.

In this case, for example, the TOC concentration measuring means and the pump 17 may be interlocked with each other. When the measured value of the TOC concentration measuring means is equal to or greater than a specific value, the pump 17 is operated and supplied to the TOC removing means. The TOC removal treatment is performed with water. In addition, an opening/closing valve may be provided in the piping 15, and the opening and closing valve and the TOC concentration measuring means may be interlocked with each other. When the measured value of the TOC concentration measuring means is equal to or greater than a specific value, the opening and closing valve is opened, and The TOC removal means supplies pure water to perform TOC removal processing. When the measured value of the TOC concentration measuring means is lower than a specific value, the pump 17 is stopped, or the opening and closing valve is closed, and the supply of pure water to the TOC removing means is stopped.

In addition to controlling the supply of pure water to the TOC removal means based on the measured value of the TOC concentration measuring means, the supply amount of pure water to the TOC removing means can be controlled. For example, the TOC concentration measuring means may be interlocked with the pump 17, and if the measured value of the TOC concentration measuring means is equal to or greater than a specific value, the number of rotations of the pump 17 is increased, and the TOC removal means is pure. The amount of water supplied increases, and the amount of pure water subjected to the TOC removal treatment increases. Further, a flow rate adjustment valve may be provided in the piping 15, and the flow rate adjustment valve and the TOC concentration measuring means may be interlocked with each other. If the measured value of the TOC concentration measuring means is equal to or greater than a specific value, the opening of the flow rate adjusting valve is increased. The amount of pure water supplied to the TOC removal means is increased, and the amount of pure water subjected to the TOC removal treatment is increased. When the measured value of the TOC concentration measuring means becomes lower than a specific value, the number of rotations of the pump 17 is lowered, or the opening degree of the flow regulating valve is reduced, and the pure water for the TOC removing means is used. The supply is reduced.

By controlling the presence or absence of the supply of pure water to the TOC removal means or the amount of supply based on the measured value of the TOC concentration measuring means, it is possible to reduce the amount of pure water by the TOC removal means, thereby reducing the correlation. The cost of the TOC removal process in pure water.

The presence or absence of the supply of pure water by the TOC removal means or the control of the increase or decrease of the supply amount can be outputted to the pump or valve based on the measured value of the TOC concentration to which the TOC concentration measuring means is input and based on the measured value. The control device of the control signal is controlled by automatic control.

4) As the power generation device 6, there are various devices such as an IPP power generation device including a high-pressure boiler.

5) Boiler overflow water discharge line - double-flow water dechlorination means - double-flow water return line Boiler vapor condensate, generally high temperature (for example, 70 ~ 97 ° C), after being discharged from the boiler as boiler overflow water After cooling to 20 to 40 ° C by the cooling means 8A (sealed cooling tower, heat exchanger, etc.), it is supplied to the double-flow water removal apparatus 10.

In FIGS. 1 and 2, the reflowing water removal apparatus 10 is exemplified by two-stage RO treatment in series → electrical dechlorination, but as long as it is a physicochemical means capable of performing dechlorination treatment, Special limitation.

6) When the RO unit 18 is used as the TOC removal means, the first heat exchanger 8B is generally RO-concentrated water at a normal temperature (5 to 35 ° C). This RO concentrated water is passed to the first heat exchanger 8B provided in the front stage of the cooling means 8A, and exchanges heat with the boiler overflow water, and the boiler overflow water is previously cooled to about 50 to 70 °C. Thereby, the burden of the cooling means 8A provided in the preceding stage of the double-flow water removing apparatus 10 is alleviated.

7) When the water temperature of the pure water tank 3 is easily reduced to a specific value or less (for example, 15 ° C or lower), the water supply of the TOC removal means is at the second heat exchanger 16 and is warmed. The water is heat exchanged and heated. Thereby, the TOC removal can be efficiently performed by the TOC removal means. When the water temperature of the pure water tank 3 is maintained at, for example, 20 to 35 ° C, the burden on the high-pressure boiler of the IPP power generation facility can be reduced.

The water temperature in the pure water supply line (pipe 2, pure water tank 3, piping 5, etc.) or TOC removal line (pipes 15, 19, etc.) may be measured, and the measured value may be a specific value or less. At the time of the low temperature, the second heat exchanger 16 is supplied with warm water so that the valve is switched and the temperature rise by the mechanism is performed. The flow rate control may be performed by adjusting the supply flow rate to the second heat exchanger 16 based on the measured value of the water temperature. As a result, the water temperature of the boiler water supply is maintained within a specific range, and the burden on the boiler is maintained within a certain range. [Examples]

[Example 1] Industrial water (TOC concentration: 2 to 3 ppm, water temperature: 10 ° C) in Chiba Prefecture was treated by the boiler water treatment apparatus of Fig. 1 and supplied to the boiler of the IPP power generation unit 6, and the boiler was Recycling of overflow water. In the pretreatment apparatus 1, condensing treatment, pressurized floating separation, two-layer filtration, and two-bed three-column ion exchange (cation exchange, decarbonation, anion exchange) are performed to produce pure water. The main conditions are indicated below and in Table 1. The results are shown in Table 1.

Average supply of industrial water (average flow in piping 2): 35m ³ /hr Pure water tank 3 Volume: 400m ³ Average water supply for IPP power generation boilers (average flow rate in piping 5): 35m ³ /hr Average flow rate of boiler overflow water (pipe average flow rate ^{7): 10 ~ 12m 3 /} hr RO apparatus 18 average water supply quantity (the average flow rate within the tube 15): ³ hr 18 average dialysis water (inner pipe 19 average flow) 34m / RO means: 30m ³ / hr 8B average flow of the first heat exchanger water: 10 ~ 12m ³ hr average flow water cooling means 8A /: 16 average water flow rate 10 ~ 12m ³ / hr of heat exchanger: 34m ³ / hr

[Example 2] The operation was carried out under the same conditions as in Example 1 except that the boiler water treatment apparatus was set to the boiler water treatment apparatus of Fig. 2 . The results are shown in Table 1.

[Embodiment 3] In the first embodiment, the second heat exchanger 16 was omitted, and the preliminary heating of the water supply of the RO device 18 was not performed, and the same conditions as in the first embodiment were carried out. Running. The results are shown in Table 1.

[Embodiment 4] In the first embodiment, the pipes 20, 21 and the first heat exchanger 8B are omitted, and the preliminary cooling of the boiler overflow water by the RO concentrated water is not performed, and The operation was carried out under the same conditions as in Example 1. The results are shown in Table 1.

[Comparative Example 1] In the first embodiment, the piping 15 for removing the TOC, the second heat exchanger 16, the pump 17, the RO device 18, the piping 19, the pipes 20, 21, and the first heat exchanger 8B are omitted. The operation was carried out under the same conditions as in the first embodiment except for the flow of Fig. 3 . The results are shown in Table 1.

As in Table 1, in Examples 1 to 4, the TOC concentration of the boiler water supply was lower than that of Comparative Example 1, and the burden on the boiler was alleviated. Compared with Example 3 in which the preliminary heating of the TOC removal line was not performed, the TOC removal rate in the same RO apparatus of Examples 1 and 4 in which the preliminary heating was performed was high. Examples 1, 2, and 4 with preparatory heating were performed, and the burden on the boiler in the latter stage was reduced. Similarly, in Examples 4 to 3 in which preliminary cooling was performed as compared with Example 4 in which preliminary cooling of boiler overflow water was not performed, the burden on the cooling means in the subsequent stage was lowered.

Although the present invention has been described in detail with reference to the specific embodiments thereof, it is obvious to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. The present application is based on Japanese Patent Application No. Hei. No. Hei. No. Hei. No. Hei.

1‧‧‧Pre-processing device

3‧‧‧Pure sink

6‧‧‧Power generation unit

8A‧‧‧Cooling means

8B‧‧‧1st heat exchanger

10‧‧‧Reflow water removal device

16‧‧‧2nd heat exchanger

11, 12, 18‧‧‧ RO devices

13‧‧‧Electrical dechlorination device

25‧‧‧UV oxidation unit

26‧‧‧Ion exchange device

Fig. 1 is a flow chart showing a boiler water treatment apparatus according to an embodiment of the present invention. Fig. 2 is a flow chart showing a boiler water treatment apparatus according to another embodiment. Fig. 3 is a flow chart showing a boiler water treatment apparatus of a comparative example.

Claims (10)

A boiler water treatment device comprising: a pre-treatment device that processes raw water to produce pure water; and a pure water supply line that supplies pure water from the pre-treatment device to the boiler, The boiler water treatment device is characterized in that: a TOC removal line is provided, and one part of pure water is taken out from the take-out portion from the pure water supply line, and TOC removal processing is performed by TOC removal means, and This treated water is returned to the take-out portion or to the pure water supply line on the upstream side. The boiler water treatment device according to the first aspect of the invention, wherein the TOC removal means includes an RO device or a UV oxidation device and an ion exchange device. The boiler water treatment device according to the first or second aspect of the invention, wherein the extraction unit or the measuring means for measuring the TOC concentration of the pure water in the pure water supply line on the upstream side is provided; When the measured value of the measuring means is equal to or greater than a specific value, the removal of the TOC by the TOC removing means or the pure water supply amount controlling means for increasing the amount of pure water supplied to the TOC removing means is started. The boiler water treatment device according to any one of the first to third aspects of the present invention, comprising: boiler overflow water for condensing exhaust steam from the boiler and discharging the boiler steam a dechlorination means for performing dechlorination treatment; and introducing the boiler overflow water from the boiler into the boiler overflow water introduction line in the recirculation water dechlorination means; and performing the dechlorination means by the reflow water The chlorine-removed double-flow dechlorinated water is returned to the aforementioned take-out portion or to the re-flowing water-removing water return line at the pure water supply line on the upstream side. The boiler water treatment device according to the fourth aspect of the invention, wherein the TOC removal means includes an RO device, and the boiler overflow water introduction line is provided with a RO concentrated water and a boiler for the RO device. A heat exchanger that exchanges water for heat exchange. A boiler water treatment method for treating raw water by a pretreatment device to produce pure water, and supplying pure water from the pretreatment device to a boiler via a pure water supply line, the boiler The water treatment method is characterized in that: one part of the pure water is taken out from the take-out portion from the pure water supply line, and the TOC removal process is performed by the TOC removal means, and the treated water is returned to the take-out portion or The pure water supply line at the upstream side is more than this. The boiler water treatment method according to claim 6, wherein the TOC removal means includes an RO device or a UV oxidation device and an ion exchange device. The boiler water treatment method according to the sixth or seventh aspect of the invention, wherein the TOC concentration of the pure water of the pure water supply line of the take-out portion or the upstream side thereof is measured, and When the measured value is equal to or greater than a specific value, the removal of the TOC by the TOC removing means is started, or the amount of pure water supplied to the TOC removing means is increased. The boiler water treatment method according to any one of claims 6 to 8, wherein the boiler overflow water for condensing exhaust gas from the boiler and discharging the boiler is discharged from the boiler The dechlorination treatment is carried out by a running water dechlorination method, and the dechlorination water subjected to the dechlorination treatment by the dechlorination means is returned to the above-mentioned take-out portion or the pure water supply line at the upstream side thereof. . The boiler water treatment method according to claim 9, wherein the TOC removal means includes an RO device, and the RO concentrated water of the RO device and the boiler overflow supplied to the reflowing water removal means The running water is heat exchanged and the boiler overflow water is cooled.