JPS625100A - Water cooling tower - Google Patents

Abstract

PURPOSE:To restrain generation of mist due to discharging air by a method wherein a dry type cooling section and a wet type cooling section are provided respectively with dampers capable of changing the opening degrees thereof freely while the opening degrees of respective dampers are controlled by detected outlet water temperature of the cooling tower. CONSTITUTION:A multitude of finned tubes is provided in the dry type cooling section 2 and water 7 flows through the tubes while air 8 flows into the cooling section 2 orthogonally to the tubes. In the wet type cooling section 3, air 8 contacts with fillers, dampened by water 7 dropping from the upper side thereof, from the side thereof to cool the water. The amount of airflow in respective cooling sections is controlled by the dampers 5, 6. The outlet temperature T2 of water 7 is detected and is compared with the lower limit value TL and the upper limit value TH of water temperature while the opening degree Z1 of the damper 5 and the opening degree Z2 of the damper 6 are controlled in accordance with the result of the comparisons whereby the mixing ratio of dry air to wet air, in which the mist is not generated by the discharging air 9, may be obtained. Thus, the improvement of circumstance may be effected.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in cooling water towers.

[Conventional technology]

Figure 3 shows the cooling tower in use. In the figure, (1) is a cooling tower, (2) is a dry cooling section, (3) is a wet cooling section, and (4) is a dry cooling section.
) is the fan, (51, (81 is the damper, (7) is the water, (
8) is the air flowing into the cooling tower, +9) +1 is the air released from the cooling tower.

In the figure, inside the dry cooling section (2), a large number of finned tubes are arranged vertically in parallel, water (7) flows inside the tubes, and air flows outside the tubes at right angles to the flow of water (7).゛(8) is configured so that it passes through. In addition, the wet cooling section (3) is a packed tower filled with packing material, and air (8) sent from the side comes into contact with the packing material whose surface is wetted by water (7) falling from the top. It is configured to cool the water using the latent heat of vaporization. Further, (5) lE5) is a louver damper, and by opening and closing the louver damper, the amount of air passing through the dry cooling section (3) and the wet cooling section can be controlled.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned cooling tower, when the outside temperature is low in winter,
When the humidity is high, the water vapor in the air discharged from the top of the cooling tower condenses and forms a white smoke-like mist, which in severe cases causes visual pollution and poses an environmental purification problem.

The present invention was made to solve the above problems, and
The purpose of this invention is to provide a control method for suppressing excessive mist generation from a cooling tower.

[Means for solving problems]

In general, in the cooling tower, the discharge air of the cooling tower (1) (
9) is the so-called floating air containing the same amount of water vapor as the outside air that has passed through the dry cooling section (2), and the wet cooling section (3).
Since the cooling water is evaporated in the air and is a mixture with humid air containing water vapor with a relative humidity of nearly 100%, the released air (9) is released into the outside air and its temperature decreases as it diffuses into the atmosphere. Depending on the weather conditions such as the temperature and relative humidity of the outside air, the water vapor in the emitted air condenses and generates mist. Generally, if the outside air is hot and dry, it is difficult to generate mist, and if the outside air is cold and humid, it is easy to generate mist. Therefore, if the amount of water vapor in the released air (9) can be detected and the amount of water vapor can be controlled according to the outside air conditions at that time, the generation of mist can be suppressed to a considerable extent. There are many difficult aspects. In addition, considering the function of the cooling tower, it is undesirable for the temperature at the outlet of the water to fluctuate due to this.

Based on the above knowledge, the inventor conducted various experiments and as a result of intensive study, in the present invention, the temperature at the outlet side of the water of the cooling tower is set to a predetermined temperature, and this temperature is detected to constantly maintain the temperature at the outlet side of the water. We have developed a control method that changes the mixing ratio of dry air and humid air in the emitted air so as to maintain it within the predetermined degree.

In other words, if the temperature on the outlet side of water exceeds a predetermined temperature, the damper (5) is closed and damper (6) is opened to increase the amount of humid air in the discharged air, and conversely, if the temperature on the outlet side of water falls, the damper ( 5
) is opened and (6) is closed to reduce the amount of humid air.

[Function] In the present invention, the amount of air passing through the dry cooling section of the cooling tower and the amount of air passing through the wet cooling section are controlled to change the mixing ratio of dry air and humid air in the discharged air. As a result, the amount of water vapor in the discharged air can be controlled, so the generation of mist due to the discharged air from the cooling tower has been significantly reduced compared to the conventional method.

[Embodiment of the Invention] Fig. 1 is a block diagram of a cooling water tower showing an embodiment of the present invention.
The figure is a damper opening control flowchart, with (1) to (
9) are the same parts as the conventional device, T, , T are the temperatures on the water inlet and outlet sides, Zl, Z2 are the Lux dampers f5), f6
1, TL indicates the lower limit of the water temperature, and TH indicates the upper limit of the water temperature.

In the figure, T1 is 40℃, T2 is 27℃, and TL is 25℃.
, TH is set at 29° C., and the mixing ratio of dry air and humid air that does not generate mist by the released air (9), that is, the opening degree (%) of the looper dampers (5) and (6), is determined by experiment. The flowchart shown in the figure shows an example of the control obtained in this way.The above series of controls that detect the temperature T2 of the water outlet side of the cooling water tower and change the opening degree of the damper are automatically performed. It will be held in

In the above embodiment, the object to be controlled by T2 detection is the damper (5L (61), but the above purpose can be achieved by controlling the rotation speed of the fan (4) and the pitch angle of the fan.

Further, the opening degree of the damper can be set arbitrarily.

〔Effect of the invention〕

According to the present invention, it is possible to maintain the water outlet temperature of the cooling tower within a predetermined temperature range and control the amount of water vapor in the discharged air, thereby suppressing the generation of mist in the discharged air, which is highly effective in improving the environment. is expected.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a cooling water tower showing one embodiment of the present invention;
The figure is a flowchart of damper opening degree control, and FIG. 3 is a block diagram of a conventional cooling water tower. In the figure, (1) is a cooling tower, (2) is a dry cooling section, (3) is a wet cooling section, (4) is a fan, (5) and (6) are dampers,
(7) is water, (8) is air flowing into the cooling water tower, (9) is discharged air, T1 is temperature at the water inlet of the water tower, T2 is temperature at the outlet side, TL
is the lower limit of the water outlet temperature, TH is the upper limit of the same temperature, 2. ．． 22 is the damper opening degree.

Claims (1)

[Claims] A cooling water tower comprising a dry cooling section that brings water and air into direct contact and cools the water using the temperature difference therebetween, and a wet cooling section that brings water and air into direct contact and cools the water using the latent heat of vaporization of the water, The dry cooling section and the wet cooling section are each equipped with a damper whose opening degree can be freely changed, and the opening degree of each of the dampers can be controlled based on the detected temperature on the water outlet side of the cooling water tower. A cold water tower.