JPS61175480A - White smoke preventing method for cooling tower - Google Patents

Abstract

PURPOSE:T prevent generation of the white smoke even in case of contacting with open air by a method wherein the dry air current which cooled hot-water through heat exchange member is contacted with the wet air current which cooled the hot-water by connecting and contacting of the air under condition diverted for at least one side thereof. CONSTITUTION:The hot-water dropped from hot-water pipes 1d drops from the holes of the hot-water drip tray 1e on the dry type heat exchange member 2. Further, rebounding drops of water drops down on the dry type heat exchange member 2 of the lower part thereof sequentially, the water cooled enough at last returns from the drip tray 1h in its place to circulate. On the other hand, the open air passes through the inside portion of the dry type heat exchange member 2 to cool the hot-water and becomes dry air 2a, in other wards, it passes through the wet type heat exchange member 3 to become wet air 3a and it contacts each other at the inside portion of the case 1c due to the operation of the fan 1b. In this case, the dry air 2a is flactionalized with the dry type heat exchange member 2 and the dry air 2a is mixed enough with the wet air 3a uniformly. In case the mixing air 4 thereof is discharged to the open air, the white smoke will never be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is used in the technical field of cooling, and particularly relates to a method for preventing white smoke when cooling water with air.

(Prior Art) A method of cooling hot water with air in a cooling tower is well known. Conventionally, there have been two methods: the so-called dry cooling method, in which hot water flows down a heat exchange pipe and the heat exchange pipe is cooled with air, and the so-called wet cooling method, in which hot water droplets falling in the atmosphere are cooled by direct air flow. Many methods are used in combination. In this case, as shown in the enthalpy diagram of Fig. 10, with respect to the saturation curve S of saturated air that has cooled hot water by a wet method, range II (in the figure) surrounded by the cooling characteristic A of this saturated air in the atmosphere The water vapor in the supersaturated region (hatched area) liquefies and becomes visible vapor, causing white smoke to rise. This white smoke causes the metal around it to rust and causes discomfort to those who see it. Although the generation of white smoke can be completely prevented if the hot water is cooled with air using only the dry method, there is a drawback that the cooling efficiency decreases.

Therefore, there has been a desire for a white smoke prevention method that does not reduce cooling efficiency in cooling towers. In response to such a request, there is a method proposed in Japanese Patent Application Laid-open No. 47-15737, but this method simply combines the dry air produced by the dry method and the moist air produced by the wet method. There is no consideration given to sufficient mixing, and the result is that the humid air is released into the atmosphere as it is, producing white smoke.

(Problems to be Solved by the Invention) In this invention, in a cooling tower that cools water with air, the conventional white smoke prevention method reduces the cooling efficiency, or even if it is not reduced, the white smoke cannot be prevented. This is an attempt to solve the problem of insufficiency.

(Means for Solving the Problems) To explain the means taken to solve the above-mentioned problems in this invention, in a counter-current type or cross-flow type cooling tower that cools water with air, A state in which a dry air flow that cools hot water without direct contact with air and a moist air flow that cools hot water through direct contact with air are separated from each other via a replacement member. The contact point is as follows.

(Function) According to the above-mentioned method of the present invention, the dry air flow and the moist air flow are brought into contact with each other in a state where at least one of them is separated, so that the two airs are sufficiently mixed, and the cooling characteristics of this mixed air are improved. is as shown in FIG. 10B, and since this cooling characteristic B does not intersect with the saturation curve S, the mixed air does not generate white smoke even when it comes into contact with the atmosphere.

(Example) A first example of the method of this invention will be described with reference to FIGS. 1 and 2.

The cooling tower 1 has a fan cylinder 1a erected at the top thereof, and a fan 1b is provided within the fan cylinder 1a.

Hot water pipes 1d are provided at the left and right upper portions of the case 1c of the cooling tower 1, and the hot water pipes 1d are arranged so that hot water drips from holes formed in the hot water pipes 1d into the hot water tray 1e at the bottom thereof. Further, a dry heat exchange member 2 and a wet heat exchange member 3 are disposed below the hot water tray 1e, and hot water is dripped onto these heat exchange members from holes drilled in the bottom of the hot water tray 1e. These dry heat exchange members 2 and wet heat exchange members 3
A looper 1f is provided on the outside (upwind side of the cooling air), a drift eliminator 1g is provided on the inside (downwind side of the cooling air), and a saucer 1h is provided below these.

As shown in FIG. 2, the dry heat exchange member 2 is provided with cylinders lined up in a staggered manner, and the gaps between the cylinders are formed as wet exchange members 3.

The hot water dripped from the hot water pipe 1d drips onto the dry heat exchange member 2 from the hole in the hot water saucer la as shown by the dashed line in FIG. The splashed water droplets are then sequentially dropped onto the dry heat exchange member 2 located below.

Finally, the sufficiently cooled water returns from the saucer 1h and circulates. On the other hand, due to the operation of fan lb, air passes through the inside of the dry heat exchange member 2 as shown by the solid line and cools the hot water to become dry air 2a, or passes through the wet heat exchange member 3 as shown by the two-dot chain line. The moist air 3a comes into contact with each other inside the case 1c. In this case, the dry air 2a is subdivided by the dry heat exchange member 2, and the dry air 2a is mixed sufficiently uniformly into the moist air 3a, and this mixed air 4 is released into the atmosphere. In this embodiment, the drift eliminator 1g, which does not generate white smoke due to cooling, prevents droplets from being entrained in the air and released into the atmosphere, thereby suppressing the humidity of the mixed air 4 and producing white smoke. further prevent the occurrence of Further, both ends of the cylinder serving as the dry heat exchange member 2 are provided with diagonally upward flanges that protrude outward.

If provided, it is possible to further prevent the above-mentioned entrainment of droplets and also prevent water droplets from scattering around the cooling tower 1. The looper If also has the function of preventing water droplets from scattering around the cooling tower 1. In addition, in the case of this embodiment, if the dry heat exchange member 2 is arranged so that the dry air 2a flowing into the upper part lc of the tower from the left and right is different from each other, the mixing of both dry and wet air can be made more uniform. Become.

Next, other embodiments will be described, and the differences from the first embodiment described above will be mainly described.

FIG. 3 shows a dry heat exchange member 2 according to a second embodiment, using a rectangular tube.

FIG. 4 shows a dry heat exchange member 2 and a wet heat exchange member 3 of the third embodiment, where the dry heat exchange member 2 is a flat cylinder that is long in the vertical direction and has an uneven surface.
In this example, horizontally flat baffle plates are arranged between dry heat exchange members 2 in a staggered manner. The irregularities on the surface of the dry heat exchange member 2 in this embodiment have the advantage of slowing down the falling speed of water droplets, prolonging the contact time with air, and improving cooling efficiency.

FIG. 5 shows the dry heat exchange member 2 and the wet heat exchange member 3 of the fourth embodiment. The dry heat exchange member 2 has a cylindrical shape with a hexagonal cross section, and only these are arranged in parallel at the top stage, and at the middle stage. A wet heat exchange member 3 is formed by spacing the dry heat exchange members 2 and arranging concavo-convex plates in parallel between them, and only the wet heat exchange members 3 are arranged in parallel at the lowest stage. In this embodiment, a rotary damper 1m is provided between the top dry heat exchange member 2 and the corresponding looper 1f as shown in FIG. 6, and if this is closed in summer,
Compared to the case where it is not closed, the air flow is concentrated in the wet heat exchange part, the amount of air passing through the wet heat exchange member 3 increases, and the rate at which hot water is cooled by the wet heat exchange member 3 increases. The cooling effect is improved, and since the outside temperature is high in the summer, no white smoke is generated.Furthermore, the unevenness of the dry heat exchange member 3 in this embodiment also slows down the falling speed of water droplets, making it easier to interact with the air. This increases the contact time and improves cooling efficiency.

7, 8 and 9 show a fifth embodiment. 7th
The heat exchange member on the left in the figure is one in which a large number of cylinders with external fins are installed as dry heat exchange members 2, and hot water rises from the lower end of each dry heat exchange member 2. The wet heat exchange member 3 is not provided, and the first deflector 11 and the second deflector 1j are provided inside the dry heat exchange member 2 (on the leeward side). The first deflector 11 is formed to vertically subdivide the dry air 2a heat exchanged with the dry heat exchange member 2, and the second deflector 1j is formed to further subdivide it horizontally. On the other hand, the heat exchange member on the right side of the figure is provided with only a known wet type heat exchange member 3, and water that passes through the dry type heat exchange member 2 and is sent via a pipe 1d drips from a saucer 1e. Further inside (downwind side) of the drift eliminator 1g, a third deflector 1h is provided. The third deflector 1h is designed to subdivide the moist air 3a that has been heat exchanged with the wet heat exchange member 3 vertically and horizontally, and this subdivision is arranged so that the subdivision position is similar to that of the dry heat exchange member 2. It is formed by arranging many rectangular funnels in a staggered manner.

Therefore, according to this embodiment, the finely divided dry air 2
A and the divided moist air 3a are embedded in each other inside the case 1c as shown in FIG. 8, and are sufficiently mixed and released into the atmosphere, similar to the above embodiment. The generation of white smoke is prevented.

In addition, in the above-mentioned embodiment, when dividing dry air and moist air, there are cases in which the air is subdivided only vertically and cases in which it is subdivided only horizontally, and these can be selected as necessary. .

A sixth embodiment is shown in FIGS. 11 to 13.

In this embodiment, a dry heat exchange member 2 is arranged on the upper side, and a wet heat exchange member 3 is arranged on the lower side.
A dry deflector 5 for guiding dry air in a substantially horizontal direction is provided inside the wet heat exchange member 3, while a wet deflector 6 for guiding moist air upward is provided substantially horizontally inside the wet heat exchange member 3. The dry heat exchange member 2 is formed by providing fins on the outer periphery of a cylinder having a turning point at the upper end and guiding hot water from the bottom to the top and then to the bottom. The dry deflector 5 has a plurality of sets of flat plates combined in a V-shape as shown in the cross section in FIG. As shown in the vertical section in the figure, multiple sets of flat plates combined in a V-shape are installed to subdivide the moist air into left and right parts.The dotted line in Figure 12 shows the concentrated position P of the moist air. The dry type and wet type deflectors 5.6 are arranged so that the air subdivision positions are alternated.

The wet heat exchange sections in the above embodiments are all cross-flow type in which the direction of hot water movement and the direction of air flow are orthogonal to each other. A seventh embodiment of the countercurrent type will be described with reference to FIG. 14. That is, in this embodiment, a wet heat exchange member 3 is installed inside the cooling tower below the dry heat exchange member 2 disposed on the upper side.
A looper 1f is provided on the peripheral wall of the cooling tower below the wet heat exchange member 3 to guide outside air to the lower part of the tower.

The dry heat exchange member 2 is composed of a tube that guides hot water downward and is provided with fins, and its water outlet pipe 7 is provided horizontally above the wet heat exchange member 3, and has a number of nozzles that spray water downward. It has holes. A drift eliminator 1g is provided above the water outflow pipe 7, and dry and wet deflectors 5, 6 similar to the embodiment shown in FIG. 11 are provided above the drift eliminator Ig.

(Effects of the Invention) The method of cooling water in a cooling tower according to the present invention uses dry air that has cooled water and moist air.

Since at least one of the two is subdivided and brought into contact with each other, the mutual contact area of dry air and humid air is large, unlike when dry air and wet air are simply brought together as in the prior art described above. The mixture is thoroughly mixed before being released into the atmosphere, and its relative humidity is reduced. Not only does it not generate white smoke even when released into the atmosphere, but its cooling efficiency is also lower than that of the conventional combined dry and wet type. It has the advantage of not decreasing compared to .

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, with FIG. 1 being a longitudinal sectional front view and FIG. 2 being a perspective view of a heat exchange member. Fig. 3 is a perspective view of a heat exchange member showing a second embodiment of the present invention, Fig. 4 is a perspective view of a heat exchange member showing a third embodiment of the invention, and Fig. 5 @ shows a fourth embodiment of the invention. FIG. 6 is a perspective view of a heat exchange member showing an example, and FIG. 6 is a partially vertical front view of the fourth embodiment. 7, 8, and 9 show a fifth embodiment of the present invention, in which FIG. 7 is a longitudinal sectional front view, FIG. 8 is a sectional view taken along the line ■-■ in FIG. 7, and FIG. The figure is a view in the direction of the ■ arrow in FIG. Figure 1O is an enthalpy/humidity characteristic diagram, Figures 11 to 13 relate to the sixth embodiment, Figure 11 is a vertical sectional view of the cooling tower, Figure 12@ is a sectional view taken along the xn-xn line in Figure 11, 1st
3 is a cross-sectional view taken along the line xm-x■, and FIG. 14 is a longitudinal cross-sectional view of the cooling tower of the seventh embodiment. 1...Cooling tower, 2a...Dry air,
3a...Group/Moist air.

Claims (1)

[Claims] (1) In a white smoke prevention method in a cooling tower that cools water with air, a moist air stream cools the water through direct contact with the air, and a dry air stream cools the water through a dry heat exchange member. 1. A method for preventing white smoke in a cooling tower, characterized by bringing the two streams into contact with each other in a state where at least one of the streams is separated.