JP2011196613A - Boiler feedwater purification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce usage of fuel in a boiler by reducing an amount of blow discharged from the boiler.SOLUTION: This boiler feedwater purification device purifies boiler feedwater fed to the boiler 6, and includes a water purifying device 1 for purifying the treated water to obtain the pure water, and a polisher device 2 through which the treated water purified by passing through the water purifying device 1 to be the pure water, passes. In the polisher device 2, an anion exchange resin 21 and a cation exchange resin 22 are arranged in series.

Description

  The present invention relates to a boiler feed water purifier for purifying (reforming) boiler feed water supplied to a boiler.

  In order to suppress the blow of boiler water, for example, as described in Patent Document 1, water supplied to the boiler is prepared. In the above-mentioned conventional technology, it is disclosed that the make-up water is softened by treating it with a water softening device containing a sodium-type cation exchange resin and a cross-flow type filtration device, thereby suppressing the amount of blow in the boiler. Has been.

JP 2008-180492 A

For the purpose of reducing the ionic components in the feed water supplied to the boiler by the inventors, pure water produced by passing raw water as make-up water through the following pure water device is supplied to the boiler. I saw it as water.
Here, the pure water apparatus is an apparatus for producing pure water by adsorbing ion components containing impurities to the ion exchange resins of the H tower and the OH tower, and extracting H ⁺ and OH ⁻ instead.

However, in the boiler supplied with the pure water, Na and silica that could not be removed by the pure water apparatus were supplied to the boiler. When these impurities are concentrated in the boiler drum, the pH concentration of the boiler water becomes excessive, which causes corrosion of the boiler tube due to alkali corrosion and a decrease in thermal efficiency due to scale adhesion.
On the other hand, impurities can be discharged out of the system by changing the amount of chemical injection or increasing the amount of continuous blow in order to reduce the concentration rate of the boiler, thereby solving the problems of alkali corrosion and scale adhesion. .

However, increasing the amount of continuous blow has a problem that the amount of combustion gas (B gas, C gas) used in the boiler increases because the amount of heat held by the boiler is discarded.
The present invention has been made paying attention to the above points, and aims to reduce the amount of fuel used in the boiler by reducing the amount of blow discharged from the boiler.

In order to solve the above problems, the invention described in claim 1 of the present invention is a boiler feed water purifier for purifying boiler feed water to be supplied to a boiler,
It comprises a pure water device for purifying treated water into pure water, and a polisher device for passing treated water that has passed through the pure water device to become pure water. The polisher device includes an anion exchange resin and a cation exchange. The resin is arranged in series.

Next, in the invention described in claim 2, in the configuration described in claim 1, the pure water device includes an H tower containing a cation exchange resin and an OH tower containing an anion exchange resin. It is characterized by being connected in series.
Next, the invention described in claim 3 is that the electrical conductivity of the treated water after passing through the polisher device is 0.56 μS / cm or less with respect to the configuration described in claim 1 or claim 2. It is a feature.

  According to the present invention, the quality of water can be greatly improved by passing the supply water made pure water by the pure water device through the polisher device. As a result, the amount of continuous blow of the boiler can be greatly reduced, and the amount of fuel used in the boiler can be reduced.

It is a schematic block diagram explaining the boiler feed water refiner | purifier which concerns on embodiment based on this invention. It is a figure which shows the relationship between Na ion concentration and electric conductivity in the treated water after processing with a pure water apparatus.

Next, embodiments of the present invention will be described with reference to the drawings.
Drawing 1 is a mimetic diagram explaining the boiler feed water refining device concerning this embodiment.

(Constitution)
As shown in FIG. 1, the boiler feed water purifier according to the present embodiment is configured by arranging a pure water device 1 and a polisher device 2 from the upstream side. Reference numeral 9 denotes a filtration device.
The pure water apparatus 1 of the present embodiment is a two-bed, three-column type pure water apparatus 1, and is arranged in the order of the H tower 3, the decarbonation tower 4, and the OH tower 5 from the upstream side.

  The H tower 3 is filled with a strongly acidic cation exchange resin. The H tower 3 purifies the supplied water into acidic treated water while regenerating the strongly acidic cation exchange resin using a mineral acid such as hydrochloric acid as a regenerant.

The decarboxylation tower 4 sends the treated water after removing the free carbonic acid in the treated water of the H tower 3 to the OH tower 5. This reduces the burden on the OH tower 5.
The OH column 5 is filled with OH type anion exchange resin. The OH tower 5 neutralizes the mineral acid acidic treated water, which is the treated water in the H tower 3, supplied via the decarboxylation tower 4, and purifies it into pure water.

  The polisher device 2 is filled with an anion exchange resin 21 and a cation exchange resin 22 in series. The polisher device 2 purifies pure water, which is treated water purified by the pure water device 1, into ultrapure water, and uses the treated water that has become the ultrapure water directly or as a storage tank (not shown). The boiler 6 can be supplied via

  In FIG. 1, a first conductivity meter 7 is interposed in a connection path between the pure water device 1 and the polisher device 2. Further, a second conductivity meter 8 is interposed on the exit side of the polisher device 2. Based on the measurement value of the first conductivity meter 7, the electrical conductivity of the treated water by the pure water device 1 is measured. Moreover, based on the measured value of the 2nd conductivity meter 8, the electrical conductivity of the treated water by the polisher apparatus 2 is measured. Then, a maintenance period such as replacement with an ion exchange resin is determined by the measured electrical conductivity.

(Operation and effect)
The raw water supplied to the boiler feed water purifier is supplied to the pure water device 1 after being filtered by the filtration device 9, and the treated water that has been purified by the processing is supplied to the polisher device 2. Here, examples of the raw water include tap water, industrial water, and groundwater.

In the polisher apparatus 2, the treated water which is the supplied pure water is passed through the anion exchange resin 21 and the cation exchange resin 22, thereby purifying the treated water made of ultrapure water, and the purified treated water is used as the boiler. Supply to boiler 6 as supply water.
Here, the electrical conductivity of the pure water purified by the pure water apparatus 1 has a value of around 3 μS / cm. FIG. 2 shows the relationship between the electrical conductivity in the treated water and the Na concentration for reference.

And the electrical conductivity of the treated water made of ultrapure water treated by the polisher device 2 depends on the anion exchange resin 21 and the cation exchange resin 22 to be filled, but is up to a value of 0.3 μS / cm or less. It is confirmed that it can be made smaller.
Here, the ultrapure water in this specification is defined as water having an electric conductivity of 0.56 μS / cm or less.

As described above, after purification to pure water by the pure water device 1, the water quality is further improved by the polisher device 2, and the electrical conductivity of the water supplied from the boiler 6 is greatly reduced.
Thereby, since impurities contained in pure water can be reduced, the concentration of Na and silica that adversely affects the water quality in the boiler 6 can be reduced. Since the concentration ratio of the boiler 6 is increased according to the ratio of the Na or silica concentration reduction width, the amount of continuous blow for discharging impurities out of the system is reduced by reducing the Na or silica concentration. The amount of heat to be used can be recovered. As a result, the amount of combustion gas used can be reduced.

The test for determining the capability of the polisher apparatus 2 was done using the boiler feed water purification apparatus of the said embodiment. As the anion exchange resin 21 and the cation exchange resin 22 filled in the polisher apparatus 2, the same ion exchange resin as the anion exchange resin 21 and the cation exchange resin 22 filled in the H tower 3 and the OH tower 5, respectively, is adopted. did.
Then, the sample on the outlet side of the OH tower 5 and the sample after passing through the polisher device 2 in the initial sampling period and the final sampling period were obtained, and the Na concentration of each sample was measured. The results are shown in Table 1.

As can be seen from Table 1, it was confirmed that by providing the polisher device 2, the Na concentration can be reduced to 1/10 or less as compared with the case where the polisher device 2 is not provided.
This is synonymous with the fact that the impurities supplied into the boiler 6 can be greatly reduced to 1/10 or less, so that the amount of continuous blow from the boiler 6 can be reduced to 1/10 or less. It is done. In addition, the Na concentration of the sample on the exit side of the polisher apparatus 2 at the end of the sampling period can be understood that the electrical conductivity is 0.3 μS / cm with reference to FIG. That is, it can be seen that the amount of continuous blow from the boiler 6 can be greatly reduced to 1/10 or less by passing through the polisher apparatus 2 and setting the electric conductivity to 0.3 μS / cm or less.

Although not shown, it is confirmed that the impurities supplied into the boiler 6 can be reduced to 1/5 or less by adjusting the polisher device 2 so that the electric conductivity is 0.56 μS / cm or less. did.
From the above, it can be seen that the electrical conductivity after passing through the polisher device 2 is preferably set to 0.56 μS / cm or less, preferably 0.3 μS / cm or less.

DESCRIPTION OF SYMBOLS 1 Pure water apparatus 2 Polisher apparatus 3 H tower 4 Decarbonation tower 5 OH tower 6 Boiler 9 Filtration apparatus 21 Anion exchange resin 22 Cation exchange resin

Claims (3)

A boiler feed water purifier for purifying boiler feed water to be supplied to a boiler,
It comprises a pure water device for purifying treated water into pure water, and a polisher device for passing treated water that has passed through the pure water device to become pure water. The polisher device includes an anion exchange resin and a cation exchange. A boiler feed water refining device, wherein a resin is arranged in series.   2. The boiler feed water according to claim 1, wherein the pure water device is configured by connecting an H tower containing a cation exchange resin and an OH tower containing an anion exchange resin connected in series. Purification equipment.   The boiler feed water purifier according to claim 1 or 2, wherein the electrical conductivity of the treated water after passing through the polisher is 0.56 µS / cm or less.

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