RU2506512C2 - Sectional ejection cooling tower - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention can be used for cooling of recirculating water. A sectional ejection cooling tower (CT) has a single housing separated into sections with curved partitions and through air-duct tunnels. A supporting frame and a water storage basin are located in lower part of the housing. An exhaust channel with a drop catcher installed inside is arranged in CT upper part above each section. All CT enclosures are made of two layers of shaped polymer sheets. Water drains - from above, wind partition walls - on sides and a lower deck - from below are enclosing surfaces of each tunnel. Curtains are mounted above tunnel inlets. Its internal volume is divided into two tiers with a process platform, the flooring of which in the middle part is of grating type. Each section has two water drains with an inclination towards each other. Headers of a water distributing system are located under water drains. In each ejector a provision is made for a hydraulic lock between an atomiser flame and an ejection channel wall. The hydraulic lock in a zone of not more than 150 mm wide from an upper edge of the channel is provided by selection of diameter and height of the ejection channel and an opening angle of the atomiser flame. During winter period, curtains fall down to the level of the process platform, thus preventing formation of icicles and formation of frost on CT structures.

EFFECT: improving CT cooling capacity, reducing energy consumption of the process, preventing formation of frost on structures during winter period.

3 cl, 4 dwg

Description

The invention relates to a power system and can be used as a circulating water cooler at medium and large industrial facilities, including power plants such as TPPs, state district power stations and nuclear power plants, and is an alternative to sectional cooling towers.

The closest in technical solutions is the ejection cooling tower (see patent RU No. 68667, F28C 1/00, 12/20/2006) - prototype. The cooling tower contains a rectangular housing, divided by a partition into equal sections. In the lower part of the casing in one of the longitudinal sides there are made air inlet windows with visors directed inward. Opposite are the air outlet windows, equipped with an additional droplet eliminator. The main droplet eliminator, covering 2/3 of the cross-sectional area, is installed in the upper part of the tower body. A water distribution manifold with ejection nozzles directed towards the air outlet windows is mounted in the openings of the air inlet windows. A drain pan is located under the tower body.

This cooling tower has the following disadvantages. As studies show, the magnitude of the ejection coefficient is very dependent on the presence or absence of a water trap between the dispersed liquid torch and the solid walls of the ejection channel. The absence of such a hydraulic lock reduces the ejection coefficient, ceteris paribus, 1.6-1.8 times. There is no water seal in this cooling tower, since it cannot be ensured with the simultaneous operation of a large number of nozzles into a single ejection channel of rectangular cross section, since star-shaped voids form at the joints of each four adjacent round flares. Through these voids there is a reverse current of a significant amount of previously ejected air from the volume of the tower, with the removal of droplet moisture, which requires a significant increase in pressure to provide the necessary value of the ejection coefficient.

The velocity of the fluid at the outlet of the nozzles in the range of working pressures of ejection coolers ranges from 10-15 m / s. When nozzles are oriented at a small angle to the horizon, the flow travels a distance of the order of 6-7 m. Thus, moving at the indicated speed, the flight period of the droplets of the dispersed liquid does not exceed one second. Since the heat and mass transfer process is very energetic, it is impossible to ensure effective cooling of water in such a short contact time of the phases. In addition, due to the presence of free space above the torch, part of the ejected air immediately rises upward towards the main drop eliminator immediately after the inclined visor, which further reduces the cooling capacity of the tower.

Devices of this design, inevitably, have a significant drop of water, because the torches of the dispersed liquid are directed towards the air outlet window.

The cooling tower has a very low density of irrigation and cannot be used at enterprises in the water cycle of which the flow rate is estimated at thousands of cubic meters per hour. In this case, with an average productivity of ejection nozzles of 4-6 m ³ / h and a distance between them of about 0.5 m, the dimensions of the cooling tower in the plan will reach several hundred meters or more.

The objectives of this invention are: increasing the cooling ability of the tower, reducing the energy consumption of the process, preventing freezing of structures in the winter, as well as improving the conditions of maintenance of the unit.

To solve these problems, a sectional ejection cooling tower has been proposed, having a single casing, divided into sections by curved walls and through air ducts. The complete localization of the active zone of the tower prevents the transfer of droplet moisture and the moistening of the air entering the ejector. The use of autonomous ejection units, in each of which the flow of a dispersed water nozzle has a guaranteed water seal in the ejection channel. In addition, the smooth forms of the flowing part, providing minimal aerodynamic drag, as well as the original movement and interaction of the coolants determine the high efficiency of the cooling process while reducing its energy consumption. The use of curtains that prevent direct ejection of cold air from the atmosphere by ejectors eliminates the freezing of structures in winter. The presence of the technological platform, ladders, stairs and the location of the water distribution system in easily accessible places outside the active zone of the cooling tower provide ease of maintenance of the unit.

A schematic diagram of a cooling tower is shown in figures 1-4. Figure 1 - General view of the cooling tower. Figure 2 is a top view of the tower. Figure 3 is a section according to figure 1. Figure 4 is a section according to figure 2.

According to the scheme, the cooling tower has a single rectangular housing 1, based on supports 2, divided into sections by curved walls 3 and through air ducts. In the lower part of the hull there is a supporting frame 4, on which a catchment basin 5 is installed. An exhaust channel 6 is arranged in the upper part of the tower above each section. The entire space between the exhaust channels is closed by a continuous metal deck forming the upper deck 7. In one of the channel end walls door 8. Inside the exhaust channel along its axis there is an internal ladder 9, on both sides of which a drip catcher 10 is installed. On the long sides of the hull at the deck level of the upper tower there are external ladders 11.

All fencing of the cooling tower 12, including the walls of the exhaust channels, are formed of profile polymer sheets in two layers.

The enclosing surfaces of each tunnel are the weirs 13 at the top, wind partitions 14 at the sides, and the continuous decking of the lower 15 deck at the bottom. Curtains 16 are mounted on both sides of the tunnel curtains in the form of a roller shutter.

The volume of each air tunnel is divided by the technological platform 17 into two tiers. The layout of the site is presented in figure 3. The flooring of the technological site consists of three parts - solid at the edges, lattice in the middle part, in the area of which an opening is made and a ladder 18 is mounted.

Each section has two weirs with a slope towards each other. On the weirs, staggered mounted in water-air ejectors 19. Directly below them are elements of the water distribution system 20.

The design of the ejection unit is presented in figure 4.

In the weir planes, circular holes are made, arranged in rows symmetrically along the collectors 21 of the water distribution system. An annulus 22 is welded from above along the edge of each hole, forming an air intake window of the ejector. The ejection channel 23 is mounted concentrically with a water ring, and a drainage gap is formed below it and the surface of the spillway. The diameter of the channel is larger than the water ring. On the collectors of the water distribution system along the axes of each ejection channel, ejection jet-vortex nozzles 24 are mounted upward.

The cooling tower works as follows.

Heated water from the consumer enters through the water distribution system 20 and is pushed out by nozzles 24 into the volume of ejection channels 23, where the required amount of air is sucked. In the summer, air enters the ejectors throughout the cross section of the airway tunnel. The diameter and height of the ejection channel, as well as the opening angle of the nozzle plume, are selected so that in the zone with a width of not more than 150 mm from the upper edge of the channel, a reliable water seal is created to prevent the backflow of ejected air from the cooling tower volume. In addition, the presence of such a water seal reduces the required pressure by 1.6-1.8 times to the level of 0.2-0.25 MPa. After the ejectors, the flows of dispersed liquid together with the ejected air move upward along curved paths. In the upper part of the section volume, a two-sided head-on collision of opposite flows occurs, accompanied by repeated crushing and droplet dropping in the process of chaotic movement. In this case, the flows seem to freeze in volume for some time. After the collision, the cooled water drops down in the form of rain. At the same time, part of the air saturated with steam, enveloping the smooth contours of the flowing part, with minimal aerodynamic drag goes into the atmosphere. Another part of the air carried away by the rain moves down. At the surface of the liquid in the catchment basin 5, the air turns and, being distributed throughout the volume, also rushes into the exhaust channel 6 of the tower, "sifting" between drops of freely falling rain.

Such a scheme for organizing the heat and mass transfer process with the nozzles oriented upward many times — up to 5 seconds or more — increases the interaction time of the heat carriers, ensuring complete saturation of the air with vapors, as well as the transfer of significantly more heat from heated water to conditionally cold air.

In addition, increasing the efficiency of the cooling process is facilitated by sealing the active zone of the tower with two-layer fences, weirs, wind walls and lower decks, which completely prevents humidification of dry atmospheric air supplied to the tower by vapor and drip moisture.

The curtains 16, lowered to the level of the technological platform 17, block the entrances to the upper tier of the air duct tunnel, forming closed spaces heated from the cooling tower volume under the weirs 13, thereby preventing the formation of icicles and freezing of structures in winter. When this air enters the ejectors 19 from the volume of the lower tier through the slots of the grating in the middle part of the technological site.

The design of the tower provides free access for maintenance personnel to almost anywhere in the volume of the tower. The rise to the lower deck 15 is carried out by stairs (not shown in the diagram). For penetration into the internal volume of the section and the bowl of the catchment basin 5, a door is made in the wind partitions 14 (not shown in the diagram). On the upper deck 7, the staff gets on the flight of stairs mounted outside the hull 1 of the tower (not shown in the diagram). A door 8 and an internal ladder 9 provide a passage into the exhaust channel 6 and movement in its volume. A staircase is arranged in each airway tunnel to ascend to the technological platform 18. The elements of the water distribution system 20 and nozzles 24 are provided with free access from the surface of the technological platform even during operation cooling towers, since weirs act as roofs, protecting personnel from falling rain.

The technological scheme of the cooling process and the proposed design of the cooling tower allow to obtain the following technical results.

The time for the interaction of coolants in the regime of intense turbulization is increased several times. The required value of the ejection coefficient is achieved with a significant decrease in the working pressure of water in the system. Dry air was supplied to the tower as a result of the complete localization of its active zones. Smooth contours of the flow part reduce the aerodynamic resistance to the movement of the flows of the vapor-air mixture.

Thus, the developed technical solutions improve the cooling ability of the unit while reducing the energy consumption of the process.

The use of curtains at the entrances of air ducts prevents the structures from freezing in the winter.

The layout scheme, as well as the presence of stairs, ramps and platforms provide convenient access for personnel to any part of the tower for maintenance.

Claims (3)

1. Sectional ejection cooling tower, containing a single rectangular housing, in the lower part of which there is a supporting frame and a catchment basin, has an exhaust channel in the upper part above each section with a drip catcher installed on both sides of the ramp, and outside the space between the exhaust channels is closed by a solid metal flooring, forming the upper deck, while all the fencing of the tower, including the walls of the exhaust channels, are formed of profile polymer sheets in two layers, so that it is guaranteed to include the removal of moisture from the active areas of the tower, characterized in that the entire tower body is divided into sections by curved walls and through air tunnels enclosing the surfaces of each tunnel are spillways on top, wind partitions on the sides, and a continuous deck deck below, above the tunnel entrances on both sides the curtains are mounted in the form of a shutter role, and the volume of the tunnel is divided into two tiers by the technological platform, and each section has two weirs with a slope towards each other, on which water-air ejectors are staggered, and collectors of the water distribution system with nozzles mounted upstream of the axes of the ejection channels are mounted under them, the diameter and height of each ejection channel and the angle of the nozzle opening are selected so that in a zone no more than 150 mm wide from the top channel edge created a reliable water seal. 2. Sectional ejection cooling tower according to claim 1, characterized in that the flooring of the technological platform consists of three parts - along the edges of the solid, in the middle part trellised for the passage of air, in the area of which the opening is made and the staircase is mounted. 3. Sectional ejection cooling tower according to any one of claims 1 and 2, characterized in that the curtains, lowered to the level of the technological platform, block the entrances to the upper tier of the air duct tunnel, forming closed spaces heated by the weirs from the cooling tower volume, thereby preventing the formation of icicles and freezing of structures in the winter.

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