JP3080753B2 - Scale cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for cleaning scale adhered to an inner surface of a circulation line.

[0002]

2. Description of the Related Art Conventionally, when scale adheres to an inner surface of a cleaning object such as a heat exchanger or a pipe in a circulation line,
Select the type and concentration of acidic chemicals according to the material and condition of the object to be cleaned, supply a predetermined amount, and perform a circulating operation with a circulating pump to reduce the scale containing metal oxides adhering to the inner surface. Dissolve. After the scale is dissolved, the acidic cleaning liquid is discharged, the inner surface is neutralized using an alkaline liquid such as ammonia, and finally, sufficient water cleaning is performed.

[0003]

In the conventional method for cleaning a scale as described above, there is a danger because chemicals such as an acidic solution and an alkaline solution are used. In addition, it requires a PH treatment or the like of the cleaning waste liquid. Further, it is necessary to stop the operation of the circulation line including the object to be cleaned during the cleaning.

[0004]

SUMMARY OF THE INVENTION A cleaning apparatus according to the present invention has an object to solve the above-mentioned problems. The cleaning apparatus is provided so as to be bypassable in a circulation line in which an object to be cleaned, a makeup water tank, and a circulation pump are connected by piping. A configuration including a cation exchange resin tower that generates an acid as a washing liquid from a neutral salt of make- up water, and a mixed bed tower of a cation exchange resin and an anion exchange resin that is installed in the circulation line so as to be bypassable. It is characterized by.

[0005]

That is, in the scale cleaning apparatus according to the present invention, the neutralized salt in the makeup water is bypassed to a circulation line in which the body to be cleaned, the makeup water tank, and the circulation pump are connected by piping. A cation exchange resin tower that generates acid as a washing liquid is installed, and a mixed bed tower of a cation exchange resin and an anion exchange resin is installed so as to be bypassable,
When the scale attached to the inner surface of the circulation line is removed by the present cleaning device, the makeup water supplied to the makeup water tank is sent to the cation exchange resin tower by the circulation pump. NaCl contained in makeup water in this cation exchange resin tower
Neutral salts such as HCl exchange only H ⁺
Is generated and sent to the circulation line as a cleaning liquid.
The scale attached to the inner surface of the circulation line is the circulation line
Is removed by dissolving with an acid such as HCl in the cleaning solution circulated . Cleaning liquid dissolution of the scale has been completed is sent by a bypass switch to the mixed bed column is removed by ion-exchange in both cations and anions, 循the circulation line
After the ring operation , pure water is returned at the exit of the mixed bed tower, and returns to the makeup water tank again. In this way, the scale attached to the inner surface of the circulation line is removed by the cation exchange resin tower and the mixed bed tower.

[0006]

FIG. 1 is an explanatory view of a scale cleaning apparatus according to one embodiment of the present invention. In the figure, a scale cleaning apparatus according to the present embodiment is provided on an inner surface of a circulation line constituted by a makeup water tank 1, a circulation pump 2, a body 3 to be cleaned such as a heat exchanger, and a pipe 4 connecting these. A strongly acidic cation exchange resin tower 5 is provided on a pipe 4 on the upstream side of the object 3 to be cleaned, and a pipe 4 on the downstream side of the body 3 to be cleaned. The mixed bed tower 6 is installed so as to be bypassable by valves 5a and 6a, respectively. The mixed bed column 6 is filled with a mixture of a strongly acidic cation exchange resin and a strongly basic anion exchange resin.

When cleaning the scale adhered to the inner surface of the circulation line, makeup water supplied to the makeup water tank 1 through the makeup water line 7 is sent to the strongly acidic cation exchange resin tower 5 by the circulation pump 2. In the cation exchange resin tower 5, neutral salts such as NaCl contained in makeup water are exchanged with H ⁺ only for cations to generate acids such as HCl and sent to the body 3 to be cleaned as a cleaning liquid. Water containing a considerable amount of salt such as general tap water or industrial water is used as make-up water (for example, 30 taps for general tap water and industrial water).
pm), or by adding NaCl. The scale containing metal oxides such as iron oxides adhered to the inner surface of the circulation line is formed by an acid such as HCl in the cleaning solution, for example, Fe ₂ O ₃ → FeCl.
_3. Dissolved and removed like CaCO ₂ → CaCl ₂ . After the removal, by switching the valves 5a and 6a, the cleaning solution in which the scale has been dissolved is sent to the mixed bed tower 6, where both cations and anions are removed by ion exchange. At the outlet of the mixed bed tower 6, pure water is formed again. Return to makeup water tank 1. When the washing is to be continued further, blow is continuously performed from a blow line (not shown) on the downstream side of the mixed-bed tower 6, and make-up water is supplied to the make-up water tank 1 or an appropriate amount of NaCl is supplied while performing circulation operation. And the like are continuously charged into the makeup water tank 1.

Conventionally, in an open-type cooling water line having a water quantity of about 10 m ³ and having a steel heat exchanger, scales such as iron oxides and calcium are generated and adhere to the inner surface of the heat exchanger. And the pressure loss of pipes,
The circulating pump and the like have been damaged and the heat exchange rate has been reduced. For this reason, the scale attached to the inner surfaces of the heat exchangers and pipes is physically removed about once every six months. This cleaning device is applied to this cooling water line, and a strongly acidic cation exchange resin tower 5 is provided upstream of the heat exchanger to which the scale adheres.
On the downstream side, the mixed bed tower 6 was provided with bypass lines provided by valves 5a and 6a, respectively. Then, 1 kg of sodium chloride (NaCl) is charged into the makeup water tank 1 and the initial P
After making H approximately 3, the circulation operation is performed for 3 hours while first passing the strongly acidic cation exchange resin tower 5, and then the mixed bed tower 6 is returned to the normal operation after passing the water for about 5 hours. A series of operations was performed once every two weeks. As a result, continuous operation for about one year was possible without breakage of the circulation pump 2 or reduction in the heat exchange rate. As described above, the present cleaning apparatus uses general tap water, industrial water, and the like as makeup water, and is particularly safe because it does not need to use an acidic liquid or an alkaline liquid.
In addition, there is no need to perform a PH treatment of the cleaning waste liquid, and it is possible to perform cleaning while continuing operation of the cooling water line, and the cleaning operation is simple and the cleaning cost is low.

[0009]

The washing apparatus according to the present invention is constructed as described above. In the cation exchange resin tower, neutral salts contained in makeup water are exchanged with H ⁺ only for cations to form acids. It is produced and sent to the circulation line as a cleaning liquid, and the scale adhering to the inner surface of the circulation line circulates through the circulation line.
It is dissolved and removed by the acid in the washing liquid operated in the ring operation ,
The cleaning solution that dissolves the scale is sent to the mixed bed tower by bypass switching and circulated through the circulation line to remove both cations and anions by ion exchange, eliminating the need to use chemicals such as acidic and alkaline liquids. It is safe, does not require the PH treatment of the cleaning waste liquid, and can continue operating the circulation line even during the cleaning.

[Brief description of the drawings]

FIG. 1 is a system diagram of a scale cleaning apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Makeup water tank 2 Circulation pump 3 Object to be washed 4 Piping 5 Cation exchange resin tower 5a valve 6 Mixed bed tower 6a valve 7 Makeup water line

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideharu Makiura 1-1, Akunouracho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (72) Inventor Masato Kawakami 1-1, Akunouracho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd. (72) Inventor Shigenori Fukuoka 5-2-5-2 Nishikujo-cho, Nara City Kyoeisha Oil & Fat Chemical Industry Co., Ltd.Nara Research Laboratory (72) Inventor Hideki Tezuka 5-2-2 Nishikujocho, Nara City 5 Kyoeisha Oil & Fat Chemical Co., Ltd. Nara Research Laboratory (58) Field surveyed (Int. Cl. ⁷ , DB name) C23G 3/04

Claims (1)

(57) [Claims] 1. A cation exchange resin tower that is provided so as to be bypassable in a circulation line in which a body to be cleaned, a makeup water tank, and a circulation pump are connected by piping and that generates an acid as a washing solution from neutral salts in makeup water. A scale washing apparatus comprising: a mixed bed tower of a cation exchange resin and an anion exchange resin which is installed in the circulation line so as to be bypassable.