JPH0366592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improved structure of a wet/dry cooling tower that prevents air discharged from the cooling tower from becoming white smoke-like.

(Prior technology) Saturated humid air discharged from a wet cooling tower is cooled by outside air conditions and becomes a visible plume (fog), so-called white smoke, which is one of the causes of pollution, so a dry cooling section is also used. Various dry/wet cooling towers have been proposed that mix the dry air from the dry air to prevent white smoke. Figure 1 shows a conventional dry/wet cooling tower, which can be divided into three types depending on the arrangement of the wet cooling section W and dry cooling section D and the direction of the air flow drawn into the tower through them. Separated.

(1) Cross-flow type with W and D orthogonal arrangement (Figure 1 A) (2) Counter-flow type with W and D opposite arrangement (Figure 1 B) (3) W and D alternating arrangement or vertical arrangement Flow type (Fig. 1 c, d) (Problem to be solved by the invention) In these conventional types, the two types of air are not sufficiently mixed in the column space in front of the suction fan, that is, the plenum room, resulting in a dry air flow and a dry air flow. Since the moist air flow is discharged in a layered manner, a visible plume (fog) layer is generated above the fan cylinder that is distinctly separated from the invisible air flow layer, so white smoke is not generated as expected. is not prevented. That is, even if the dry and wet air temperature and ratio that do not generate a visible plume can be calculated according to the moist psychrometric diagram, in reality, only an unsatisfactory result is obtained because the mixing of both air is insufficient.

Furthermore, the cooling effect of dry cooling using indirect heat transfer using finned tubes is theoretically smaller than that of wet cooling using the latent heat of vaporization due to direct contact with air and water in the filling material. In combined cooling towers, the dry cooling section is installed vertically on the side, so
Due to various restrictions in terms of the arrangement and structure in relation to the wet cooling section, it is necessary to select a tower that is several steps larger in size than a wet cooling tower of the same capacity, which is unavoidable in terms of cost.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned difficulties of conventional dry cooling towers. The hot water flowing down through the stationary packing material section into the lower cold water tank and the air flow sucked into the column internal space from outside the packing material section by a suction fan are brought into direct cross-flow contact at the packing material section. Wet and dry type cooling incorporates an air heater that indirectly heats the air drawn into the tower space into the wet cross-flow cooling tower section that cools hot water to prevent the air discharged from the tower space from turning into white smoke. In the tower, by reducing the width of the cold water tank to a width that can receive the flowing water from the filling material section and installing it on a foundation that allows ventilation, an opening that can suck air is created at the bottom of the tower. The air heater is installed in the opening, and the air heater is installed above the air heater to deflect the flow of high-temperature dry air sucked into the column internal space toward the packing material part, and to receive falling water droplets from the column internal space. The damper is characterized in that a plurality of damper blades each having a water receiving gutter formed at the lower edge for stopping and discharging water are arranged in a row and tilted in the direction of the filling material part.

(Function) According to the present invention, the saturated humid air sucked from the cross-flow type wet cooling section and the dry air sucked upward from the dry cooling section roughly cross-flow in the tower interior space (plenum room) and are tightly cooled. The prevention of visible plumes is ensured since the mixing effect is enhanced, especially by deflecting the upstream dry air towards the non-uniform distribution of the humid air flow. In this case, since the falling water droplets from the inner space of the tower are caught and discharged by the damper blades, the amount of moisture in the dry air is minimized.

Structurally, in order to install a dry cooling section, the width of the cold water tank for the wet cooling section should be reduced to the minimum necessary, and the foundation should be structured to allow ventilation, with air suction openings on the bottom of the tower to prevent the suction of dry air. Therefore, the cooling function can be made similar to conventional wet cooling towers in terms of superstructure, size and rated capacity of the wet cooling section, since only the fan capacity needs to be increased, which does not particularly increase costs or increase the installation area. I don't invite anyone. If the weather conditions do not produce white smoke, it is possible to close the dry cooling section and utilize the advantageous cooling function of the wet cooling section.

(Example) Hereinafter, the present invention will be explained specifically and in detail with reference to the examples shown in FIGS. 2 to 4. 2nd and 3rd
The figure shows an embodiment in which the wet cooling section is constructed as a double-flow cross-flow type cooling tower, and FIG. 4 shows an embodiment in which the wet cooling section is also a single-flow type.

In Figures 2 and 3, the wet cross-flow cooling tower part is not directly on the ground, but has a concrete foundation 1 erected on the ground at intervals, and shaped steel frames 2, etc. installed in a row at intervals on top of the concrete foundation 1. It is installed on a pedestal that allows ventilation and constitutes the upper wet cooling section. The ventilation frame can also be placed underground or semi-underground.

A filling material section 4 is provided on both sides of the pedestal with a plenum chamber 3 in the middle, and a suction ventilation device consisting of a fan 5, a speed reducer 6, a motor 7, and a fan cylinder 8 is provided on the upper deck of the tower. is sucked into the plenum chamber 3 through the filler part 4 and discharged upward from the fan cylinder 8. A looper 9 is provided on the air intake surface of the filler portion 4, and an eliminator 10 is provided on the air outlet surface.

The hot water to be cooled is supplied to the hot water distribution tank 11 above each filling material section 4 via hot water pipes 12 and water sprinkler box 13, disperses the filling material section 4, is cooled by direct contact with air, and flows into the cold water tank 14 below. It flows down towards the direction.

In the present invention, the hot water pipe 12 that controls the amount of flowing water
A flow control valve 15 is provided at the outlet of the cold water tank 1.
4 is not formed on the entire bottom surface as in the past, but is limited to the lower part of each filling material section 4 and is divided into two parts, reducing the effective width to enough to receive all the adjusted amount of cooling water that falls from the filling material section. An air suction opening 16 at the bottom of the column is opened below the plenum chamber 3 in the gap between the two cold water tanks 14 created. Each cold water tank 14 with a reduced plane area is given enough depth to prevent cold water from overflowing, and the cold water is quickly taken out from a cold water outlet 17 via a sump 26.

An air heater 18 consisting of a group of finned tubes is installed in the tower bottom air opening 16, and hot water associated with the hot water pipe 12 or high temperature water from another water source flows through the inlet pipe 19 thereof. Do it like this. 25 indicates the air heater outlet piping. A damper 21 consisting of a row of damper blades 21 having a roughly J-shaped cross section is provided above the air heater 18. Give a slope of 20. In this way, the air drawn in from the outside by the fan 5 from the ventilation-permeable foundations 1 and 2 in a parallel flow relationship with the air passing through the filling material section is heated through the air heater 18 and passed through the damper 21 into the plenum chamber 3. As shown by the dotted arrow d, the filling material portion 4
The flow is biased toward the inner surface of the air, and approximately crossflows with the air shown by the solid arrow w that has passed through the filler portion 4 and the eliminator 10.

The plurality of damper blades 20 are designed to have vertical overlap between adjacent blades so as to receive all the falling water droplets that are generated by the coalescence of the passing water droplets in the moist air w that has passed through the eliminator 10, and also have J-shaped cross-section blades. The lower edge is formed into a water receiving gutter 22 for the sewage flowing from the wing surface, and the water collected in the water receiving gutter 22 flows to the end and damper 2.
Air heater 1
Minimize as much as possible the dry air from 8 being moistened.

The flow rate of air passing through the filling material part 4 is usually 2 to 4
m/sec, but the flow of humid air w passing through the eliminator 10 is by no means uniform and varies significantly depending on the location. As shown in FIG. 5A, the filler part 4 and the eliminator 10 are horizontally divided into a number of spans by support columns 24, and the flow velocity distribution diagram shown in FIG. As shown, there is almost no flow of humid air. Therefore, between the humid air w and the dry air d that roughly cross-flow, the dry air d that is deflected toward the eliminator 10 enters the area where there is almost no flow of humid air, and thus the flow of both air flows is reduced. Since the mutual contact diffusion area is increased, a better air mixing effect within the tower can be obtained compared to the conventional type cooling tower that combines dry and wet cooling towers.

FIG. 4 shows another embodiment of the present invention, in which the wet cooling tower is of a single-flow type with a packing material section 4 on only one side.
It has been established. Parts that are equivalent to the embodiments in FIGS. 2 and 3 are indicated by the same reference numerals in the figures, and
Omit duplicate explanations.

(Effects of the Invention) The structural functions of the wet and dry cooling tower of the present invention are as described above, and the present invention provides the following effects.

The wetting of the saturated moist air and the dry air within the column is thus very intimate, so that the formation of visible plumes from the exhaust air is effectively prevented. There is no need to provide a special mixing chamber to facilitate mixing. Since the bottom of the tower, which cannot be used in a normal cooling tower, is used as a place to install an air heater for supplying dry air, effective use of floor space can be achieved. In addition, in conventional wet/dry cooling towers, the dry section is a vertical side device, so there are various restrictions in terms of layout and structure, so we selected a tower type with several stages higher capacity than a normal wet cooling tower. This inevitably led to an increase in costs. In contrast, in the present invention, restrictions on the installation location of the dry section are alleviated, and the need for class-up of the tower type is minimized.
The only solution is to increase the capacity of the fan to suck in dry air, which is advantageous in terms of cost.

In addition, with conventional dry/wet cooling towers, there are restrictions on air intake when arranging them in a row to create a multi-cell structure. In the present invention, air heaters with a capacity commensurate with the amount of heat of each cell are arranged at the bottom of the tower, so it is easy to form a multi-cell structure without interfering with the arrangement in rows. There will be no problem with air intake as long as consideration is taken to ensure that the steel frame and concrete foundation do not impede air inflow.

[Brief explanation of drawings]

Figure 1 shows the layout of each part of a conventional combined dry/wet type cooling tower.
FIG. 1B is a plan layout of a counter-current type, FIG. 1C is a plan layout of an example of a parallel flow type, and FIG. FIG. 2 is a longitudinal cross-sectional side view of a wet and dry cooling tower according to one embodiment of the present invention, and FIG.
FIG. 4 is a vertical cross-sectional side view of a wet/dry cooling tower according to another embodiment of the present invention; FIG. FIG. 5B shows the corresponding flow situation, and shows a moist air flow velocity distribution curve, with the horizontal axis representing the location of the support and the vertical axis representing the flow velocity in the downward direction. 1...Concrete foundation, 2...Shaped steel frame, 3
... Plenum chamber, 4 ... Filler section, 5 ... Fan, 6 ... Reduction gear, 7 ... Motor, 8 ... Fan cylinder, 9 ... Looper, 10 ... Eliminator, 11 ... Hot water distribution tank , 12...Hot water pipe, 13
... Watering box, 14 ... Cold water tank, 15 ... Flow rate control valve, 16 ... Tower bottom air intake suction opening, 17 ...
Cold water outlet, 18... Air heater, 19... Inlet piping, 20... Damper blade, 21... Damper,
22...Water receiving gutter, 23...Water collection gutter, 24...Strut, 25...Outlet piping, 26...Sump, W...
Wet cooling section, D...Dry cooling section, w...Moist air flow, d...Dry air flow.

Claims (1)

[Claims] 1 The hot water flowing from the upper hot water distribution tank through the stationary filling part to the lower cold water tank and the air flow sucked into the column internal space from outside the packing part by a suction fan are combined into the filling material. In contrast to the wet cross-flow cooling tower section, which cools hot water by direct contact with cross-flow at the
In a wet/dry cooling tower that incorporates an air heater that indirectly heats the air drawn into the tower interior space to prevent the air discharged from the tower interior space from becoming white smoke, the cold water tank is connected to the water flowing from the filling material section. By reducing the width to an acceptable width and installing it on a foundation that allows ventilation, an opening is created at the bottom of the tower through which air can be sucked.The air heater is built into this opening at the bottom of the tower, and an air heater is installed above it. A plurality of water-receiving gutters are formed at the lower edge to deflect the flow of high-temperature dry air sucked into the tower interior space through the container toward the packing material part, and to catch and discharge falling water droplets from the tower interior space. What is claimed is: 1. A cooling tower for both dry and wet use, characterized by having air volume adjusting dampers arranged in rows with damper blades tilted in the direction of the filling material section.