JPH07290092A - Method for monitoring contamination of circulating water pipeline and device therefor - Google Patents

Abstract

PURPOSE:To grasp the contamination of a circulating water pipeline more quickly and directly, grasp or predict the contamination by a simple structure and provide an index by which an accurate measure is taken. CONSTITUTION:A tube 1 for monitoring contamination consists of a PVC tube 2 having 16mm inner diameter and 200mm length and a net 3 contaminant depositing means fixed to the wall face of the tube 2 at its central part. The net 3 is made of stainless steel and has 16 mesh. The tube 1 is connected to a part of a circulating water pipeline, and the contaminant of the circulating water depositing on the net 3 is monitored from outside the tube 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for monitoring the state of pollution in circulating water system pipes, and more particularly to corrosion, scale and slime in industrial water pipes such as open circulation type or closed circulation type cooling water systems. The present invention relates to a method and an apparatus for monitoring the status of contamination by the like There are various circulating water system pipes to which the present invention can be applied, such as pipes for steelmaking, chemical and petrochemical and other process cooling, and pipes for building air conditioning.

[0002]

2. Description of the Related Art A large amount of cooling water is used for cooling various processes such as steel making, chemicals, or for building air conditioning. With the increasing use of cooling water, to save cooling water,
Advanced cooling water is being used by changing from a single cooling water system to a circulating cooling water system or implementing highly concentrated operation. When such advanced use of cooling water is carried out, the water quality of the circulating cooling water deteriorates due to the concentration of dissolved salts, etc., and the retention time increases, causing "contamination of corrosion products, scale exudates, slime, etc." The amount of substances increases, which causes obstacles such as blockage and flow rate reduction.

Further, when "contaminants" adhere to the metal surface of heat exchangers and pipes and the lower part becomes an anaerobic atmosphere, sulfate reducing bacteria grow and hydrogen sulfide is produced to corrode. The reaction may be accelerated. Corrosion under the adhesion of such "pollutants" also occurs in corrosion resistant materials such as copper, copper alloys and stainless steel. For this reason, various proposals have been made to constantly detect the state of pollution in the circulating water system pipes so that the pollution can be detected early and appropriate measures such as adding water treatment chemicals can be taken.

[0004]

As a means for grasping contamination in the cooling water system, a stainless pipe is connected to a bypass pipe or a branch pipe provided in the circulating water pipe, and after a certain period of time, contaminants adhere to the pipe. It is common practice to observe the situation. However, a long test period of one month or more was required to accurately grasp the adhesion status, and it was not possible to quickly know the adhesion status in the system. Therefore,
(1) The amount of suspended solids of cooling water and the concentration multiple of cooling water are measured (JP-A-3-288586), (2) The number of bacteria and the amount of slime are measured (Uchida Otsukaku Shinsha "Industrial water treatment""Published July 5, 1968, see pages 182-198) and the like have been proposed. Since all of these are indirect means of grasping, they cannot be said to faithfully reflect the pollution situation in the pipe.

(4) A small heat exchanger is installed to measure the temperature change of the cooling water (Japanese Patent Laid-Open No. 61-246590).
(5) Measuring the change in the heated pipe surface temperature (Japanese Patent Laid-Open No. 2-96644), but the whole grasping means including the sensor is complicated and the device becomes large-scale. It is disadvantageous in terms of workability and economy.

An object of the present invention is to provide an index which enables quicker and more direct grasp of pollution in circulating water system piping and grasping or predicting contamination in circulating water system piping with a simple structure to take appropriate measures. Another object of the present invention is to provide a method and apparatus for monitoring the state of pollution in circulating water system piping.

[0007]

The method for monitoring the state of contamination in a circulating water system pipe according to the present invention is transparent, comprising a contact member capable of adhering pollutants in the circulating water inside a part of the circulating water system pipe. This is a method in which a pipe is installed and the state of contamination inside the pipe is detected by an external monitor.

The apparatus for monitoring the state of pollution in the circulating water system pipe of the present invention is a transparent pipe installed in a part of the circulating water system pipe and capable of monitoring the inside of the pipe from the outside, and circulating water installed in the transparent pipe. It is a device for detecting the state of contamination in a pipe provided with a net to which contaminants can adhere. The circulating water system piping according to the present invention refers to industrial water piping such as an open circulation type or closed circulation type cooling water system.

From the viewpoint of workability, the transparent pipe is preferably connected to a bypass pipe or a branch pipe provided in the circulating water system pipe. It is desirable that the contact member is a mesh-like contaminant adhering means because the contaminant can be quickly confirmed. It is desirable that the contaminant adhering means is a net made of metal or synthetic resin in order to prolong the service life.

The mesh opening is 5 to 30 mesh,
It is preferably 10 to 20 mesh because it is possible to quickly confirm the attachment of contaminants. If less than 5 mesh or more than 30 mesh,
The deposition rate of pollutants decreases, and the prediction of pollutant generation is delayed.

The flow velocity of the circulating water passing through the transparent tube is 0.1.
To 1.0 m / sec, preferably 0.3 to 1.0 m / sec
Seconds is desirable in that the adherence of contaminants can be quickly confirmed. If the flow velocity is less than 0.1 m / sec or more than 1.0 m / sec, the adherence speed of the pollutant becomes low, and the prediction of the pollutant generation is delayed.

[0012]

In the method and apparatus for monitoring the state of contamination in the circulating water system according to the present invention, contaminants in the circulating water adhere to the contact members inside the transparent pipe arranged in a part of the circulating water system pipe.
If this is monitored from the outside, the state of contamination inside the pipe can be directly understood. This monitor also serves as an indicator for appropriate drug injection or other pollution prevention measures.

Further, by connecting the transparent pipe to a bypass pipe or a branch pipe provided in the circulating water system pipe, the contamination state in the pipe can be easily grasped, and the contact member in the transparent pipe can be easily taken out and used for analysis. You can Further, when the contact member is composed of the mesh-like contaminant adhering means, the contaminants in the circulating water can be adhered to the surface at a higher adhering rate, so that the contamination in the circulating water system pipe can be predicted quickly. . The material of the net is preferably made of metal or synthetic resin, and the metal net is preferably made of stainless steel having corrosion resistance.

Further, when the mesh size of the mesh is 10 to 20 mesh, the pollutants of the circulating water can be adhered to the surface at a high adhering speed, and the pollutants generated in the circulating water system pipe can be predicted early. . Further, if the circulating water system pipe or the transparent pipe is set so that the flow velocity of the circulating water passing through the transparent pipe is 0.3 to 1.0 m / sec, the pollutant of the circulating water is attached to the surface at a high attachment rate. This enables early prediction of pollutants.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in the drawings. The present invention is not limited to this. 1 and 2 show a transparent tube (hereinafter referred to as a monitor tube) provided with a contact member capable of adhering pollutants of circulating water to the inside thereof used in the method and apparatus for monitoring the pollution situation of the present invention. The monitor tube 1 is composed of a transparent tube 2 and a mesh 3 which is a contact member and serves as a contaminant attachment means. Transparent tube 2 has an inner diameter of 16 m
m, outer diameter 22 mm, length 200 mm made of vinyl chloride resin. The inner diameter of the transparent tube 2 is preferably 10 to 25 mm from the viewpoint of equipment construction and handling, and the length is 20 for the same reason.
0 to 300 mm is desirable. The material of the transparent tube 2 may be glass or acrylic resin as well as vinyl chloride resin.

The mesh 3 is inserted into the transparent tube 2 in a state of being wound so as to cover the inner wall of the transparent tube 2, and the elastic force thereof causes the transparent tube 2 to be inserted.
It is fixed to the wall in the center of the. The mesh 3 is made of stainless steel (SUS-304) and has an opening of 16 mesh. The monitor pipe 1 can be connected to the pipe by a socket (not shown).

FIG. 3 shows an open circulation type cooling water system in which the monitor pipe 1 is arranged. In the open-circulation cooling water system 4, the pump 5 sends the cold water to the multi-tube heat exchanger 6 to guide the hot water to the cooling tower 7. A bypass pipe 8 is connected to a pipe on the downstream side of the pump 5, and a plurality of detachable monitor pipes 1 are connected to the bypass pipe 8 in parallel. Before and after the monitor tube 1, valves 9 for arbitrarily setting the flow velocity in the monitor tube 1 are installed. The cooling tower 7 has a tank 10 and a pump 1 for introducing a chemical into the cooling water system 4.
1 is connected.

In such a structure, the contamination state of the net 3 in the monitor tube 1 can be visually checked from the outside or by a television camera to accurately grasp the time when the medicine is introduced or other anti-adhesion measures are taken. You can
The chemicals introduced are anticorrosive agents (phosphate, phosphonate,
Divalent metal salts, carboxylic acid low molecular weight polymers, nitrites, chromates, amines, azoles, etc., scale inhibitors (carboxylic acid low molecular weight polymers, phosphonates), slime inhibitors (chlorine agents, no. Quaternary ammonium salt-based chemicals, bromine-based chemicals, organic nitrogen-sulfur-based chemicals, etc.), slime removers, sludge accumulation inhibitors, etc. Other measures to prevent adhesion include pH adjustment, changes in the operating conditions of the heat exchanger,
There is softening and desalination of makeup water.

[Experimental Example 1] The monitor tube 1 in the above example was connected to an industrial cooling water system as a sample, and the contaminants adhering to the monitor tube 1 were observed and measured. (Test method) As shown in FIG. 4, a branch pipe was introduced from the cooling tower outlet pipe of the cooling water system of the steel mill hot rolling mill, and the adhesion test unit 14 consisting of the monitor pipe 1 and the stainless pipe 12 was connected to this branch pipe. . Stainless tube 12 is monitor tube 1
It has the same inner diameter (16 mm) and length (200 mm). A valve 13, a tank 10 for introducing a drug, and a pump 11 were connected to the branch pipe.

Four types of tests were set for the case where no chemical was added and the case where sodium hypochlorite (effective chlorine 12%) was added, and each test was followed to measure the adhered amount over 30 days. And observations were made. The flow rate of the cooling water flowing through the monitor tube 1 and the stainless tube 12 was set to 0.6 m / sec. The results are shown in Table 1, FIG. 5 and FIG. The photographs (copies) shown in FIG. 5 are photographs of the nets 3 taken out from the monitor tube 1 and expanded. FIG. 6 shows changes in the adhered amount over time (day). Table 2 shows the analysis results of the composition of the deposit.

[0021]

[Table 1]

[0022]

[Table 2]

As is clear from the test results, the state of contamination of the net 3 in the monitor tube 1 according to the embodiment of the present invention has a correlation with the amount of the stainless tube adhered, and the adherence of dirt can be confirmed quickly. I understand. It can be seen that the amount of adhesion of the stainless steel pipe can be reduced by adding a water treatment chemical (sodium hypochlorite) after confirming the stain on the monitor pipe 1 (see Test No.).

[Experimental Example 2] As in Experimental Example 1, the monitor tube 1 was attached to an industrial cooling water system as a sample, and the contaminants adhering to the piping were observed and measured. (Test Method) As shown in FIG. 7, the adhesion test unit 14 similar to that of Experimental Example 1 was installed in the cooling tower outlet pipe of the cooling water system of the steel plant continuous casting factory.

Two types of tests were set, that is, no drug was added and sodium hypochlorite (effective chlorine 12%) was added, and in each test, the daily change in the adhered amount over 30 days was observed and measured. The flow rate of the cooling water flowing through the adhesion test unit 14 was set to 0.6 m / sec. The results are shown in Table 3 and Table 4.
Shown in.

[0026]

[Table 3]

[0027]

[Table 4]

As is apparent from the test results, the state of contamination of the net 3 in the monitor tube 1 according to the embodiment of the present invention has a correlation with the amount of the stainless tube attached, and the attachment of dirt can be confirmed quickly. I understand.

[Experimental Example 3] As in Experimental Example 1, the monitor tube 1 was attached to an industrial cooling water system as a sample, and the contaminants adhering to the piping were observed and measured. (Test Method) As shown in FIG. 8, an adhesion test unit similar to that of Experimental Example 1 was installed in a tuyere outlet pipe of a tuyere indirect cooling water system at a steel mill.

Two types of tests were set up: no chemicals added and sodium hypochlorite (effective chlorine 12%) + scale inhibitor added, and in each test, observation and measurement of the daily change in the adhered amount over 30 days. I went. Adhesion test unit 10
The flow velocity of the cooling water flowing through was set to 0.6 m / sec. The results are shown in Tables 5 and 6.

[0031]

[Table 5]

[0032]

[Table 6]

[Experimental Example 4] A monitor tube 1 in which a mesh having different mesh roughness (opening) is fixed to a transparent tube 2 is prepared, and this monitor tube 1 is attached to a cooling water system as a sample to measure mesh roughness ( The relationship between (opening) and the amount of adhesion was measured. (Test method) A branch pipe was introduced from a cooling tower outlet pipe of a cooling water system of a steel mill cold rolling mill similar to that of Experimental Example 1, and six monitor pipes 1 were connected in parallel to the branch pipe. At the center of the monitor tube 1, a stainless mesh having openings of 5 mesh, 10 mesh, 12 mesh, 16 mesh, 20 mesh and 28 mesh was attached. The flow rate of the cooling water passing through each monitor tube 1 was set to 0.5 m / sec. The amount of adhesion to each of the above nets after passing water for 10 days is shown in FIG. 9 in relation to the opening of the wire net.

From FIG. 9, a large adhesion amount can be obtained when the mesh size is 10 to 20 mesh. It can be seen that when the amount is less than 5 mesh, the adhesion amount is drastically reduced, and when the amount is more than 30 mesh, the adhesion amount is also reduced. The mechanism of attachment to the net is that microorganisms first attach to the surface of the wire, and then an adhesive substance is generated in the surroundings. This sticky substance acts as a binder to attach the inorganic suspended substance. It is considered that this further promotes the adhesion.

[Experimental Example 5] The relationship between the flow velocity in the pipe and the deposition rate was measured. (Test method) A branch pipe was introduced from the cooling tower outlet pipe of the steel mill hot rolling mill shown in FIG. 4, and six monitor pipes 1 used in Experimental Example 1 were arranged in parallel in this branch pipe as shown in FIG. Connected In front of the monitor pipe 1, a valve 13 for arbitrarily setting the cooling water flow velocity in the monitor pipe 1 was connected. The adhesion rate was shown by calculating the weight difference between before and after passing water through the wire net of the monitor tube 1 and converting it into mg / cm ² / month.
The results are shown in Fig. 11.

From FIG. 11, the deposition rate is 0.6 m in the pipe.
It can be seen that a peak is exhibited around / sec, and that the adhesion does not easily proceed in a region of less than 0.1 m / sec or over 1.0 m / sec. It is considered that this is because the amount of foreign matter that adheres is reduced in the region where the flow velocity in the pipe is low, and it becomes difficult to adhere due to the shearing force of the flow in the region where the flow velocity in the pipe is high.

[Other Embodiments] In the above-mentioned embodiment, the net 3 is fixed to the inner wall surface of the monitor tube 1, but as shown in FIG. 12, the small diameter net 15 is fixed in the transparent tube 2 by the fixing member 16. Net 1
The monitor tube 17 may be configured to be capable of externally monitoring the adhered matter adhered to the outer peripheral surface of 5.

[0038]

According to the method and apparatus for monitoring the pollution condition in the circulating water system pipe of the present invention, the pollution condition in the pipe can be directly grasped by monitoring the contaminants in the circulating water adhering to the contact member from the outside of the transparent pipe. can do. Therefore, the contamination state can be grasped with a simple configuration. In addition, it can be used as an index for accurately ascertaining the timing of analysis of pollutants or appropriate measures to prevent adhesion such as chemical injection. Also, by connecting the transparent pipe to the bypass pipe or branch pipe provided in the circulating water system pipe, the contamination state inside the pipe can be more easily grasped and the contact member can be easily taken out from the transparent pipe to analyze the attached pollutants. Or the contact member can be replaced.

Further, when the contact member is composed of a mesh-like contaminant adhering means, the contaminants in the circulating water can be adhered to the surface at a higher adhering speed. For this reason, the contaminants will adhere to the monitor pipe of the present invention before the contaminants adhere to the circulating water system pipe, and it becomes possible to predict the contamination in the pipe. If this contaminant adhering means is composed of a wire net, it is possible to prevent wear and extend the life. Further, if the contaminant adhering means is composed of a net made of synthetic resin, it is possible to extend the service life of the circulating water system piping, which is highly corroded by metal.

If the mesh size of the mesh is 10 to 20 meshes, the adherence rate of contaminants can be increased and the contaminants can be predicted early. Further, if the circulating water system pipe and the transparent pipe are configured so that the flow velocity of the circulating water passing through the transparent pipe is 0.1 to 1.0 m / sec, the adherence speed of the pollutant can be increased, and the pollutant can be quickly removed. Prediction is possible. Based on this prediction, it is possible to prevent contamination of the circulating water storage by taking measures to prevent adhesion such as addition of an appropriate water treatment chemical.

[Brief description of drawings]

FIG. 1 is a perspective view of a monitor tube 1 according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a diagram showing a configuration of an open-circulation type cooling water system in which a monitor pipe 1 is arranged.

FIG. 4 is an explanatory diagram of a cooling water system of a hot rolling mill of a steel mill of Experimental Example 1.

5 is a copy of a photograph showing the adhesion state as a result of Experimental Example 1. FIG.

FIG. 6 is a diagram showing a change with time in an adhesion amount as a result of Experimental Example 1.

FIG. 7 is an explanatory diagram of a cooling water system of a steel plant continuous casting factory of Experimental Example 2.

FIG. 8 is an explanatory view of an indirect cooling water system of a steel pig iron factory tuyere of Experimental Example 3.

FIG. 9 is a diagram showing the relationship between the roughness of the mesh and the adhesion amount as a result of Experimental Example 5.

FIG. 10 is a diagram showing an adhesion test pipe of Experimental Example 5.

FIG. 11 is a diagram showing the relationship between the in-pipe flow velocity and the deposition rate as a result of the deposition test of Experimental Example 5.

FIG. 12 is a monitor tube 1 as another embodiment of the present invention.
3 is a diagram corresponding to FIG.

[Explanation of symbols]

 1,17 Monitor tube (pollution status monitoring device) 2 Transparent tube 3,15 Net (contact member)

Claims (7)

[Claims] 1. A transparent pipe provided with a contact member capable of adhering pollutants of circulating water inside a part of the pipe of the circulating water system, and the contamination state in the pipe is detected by an external monitor. Method of monitoring the status of pollution in circulating water piping. 2. The method for monitoring the pollution status in the circulating water system pipe according to claim 1, wherein the transparent pipe is connected to a bypass pipe or a branch pipe provided in the circulating water system pipe. 3. The method for monitoring the pollution condition in the circulating water system pipe according to claim 1, wherein the contact member is a mesh-like contaminant adhering means. 4. The method for monitoring the state of contamination in a circulating water system pipe according to claim 3, wherein the contaminant adhering means is a net made of metal or synthetic resin. 5. The method for monitoring the state of contamination in the circulating water system piping according to claim 4, wherein the mesh size of the mesh is 10 to 20 mesh. 6. The flow rate of the circulating water passing through the transparent tube is 0.
The method for monitoring the pollution status in the circulating water system pipe according to claim 1, wherein the method is 3 to 1.0 m / sec. 7. A transparent pipe, which is installed in a part of the circulating water system pipe and can monitor the inside of the pipe from the outside, and a net which is installed inside the transparent pipe and to which pollutants of the circulating water can adhere. A circulating water system piping contamination status monitoring device that detects the status of contamination in the piping.