RU2306513C1 - Combination cooling tower - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: invention relates to heat exchange devices and it can be used in recirculating water supply systems of thermal power stations and industrial enterprises where chimney type and/or mechanical draft towers are used. Proposed combination cooling tower has housing in form of stack with air inlet ports in lower part or housing of fan, water trap, water collecting reservoir arranged under cooling tower, water distributing system with spray nozzles whose outlet holes are pointed upwards and spraying device. Spray nozzles, for instance, involute type ones, are arranged at a distance from top of spraying device equal to 0.1-1.0 h where is height of spraying device. Water head before spray nozzle should be within 0.2 - 1.0 atm. Stack can be made in form of fan housing.

EFFECT: increased active area of cooling tower without increase of aerodynamic resistance.

2 cl, 1 dwg

Description

The invention relates to a power system, in particular to heat exchangers, and can be used in water recycling systems of thermal power plants and industrial enterprises, where tower and / or fan cooling towers are used.

In all types of tower and fan cooling towers there is: a water distribution system designed to evenly distribute water over the useful area of the tower, an irrigation device, which is the active area of heat removal in the cooling towers, and an air distribution space that provides access to the air flow over the entire internal area of the tower, while cooling circulation water, as shown by field tests, in the water and air distribution spaces is minimal.

Known nozzle for a heat exchanger (cooling tower irrigation device) containing vertical mesh sheets made of mutually intersecting non-metallic threads with the formation of cells between them in the form of a parallelogram (RF patent No. 2133938, IPC F 28 F 25/08, publ. 07.27.1999 g .).

The disadvantage of the analogue is that the improvement of the irrigation device of the cooling tower goes along the path of increasing its cooling ability by increasing the free water surface, turbulizing air and water flows, and, as a result, all this due to the increase in aerodynamic resistance of the cooling tower. With the development of the irrigation device in height or an increase in its density (resistance), the air flow passing through the cooling tower is associated. Reduced air consumption leads to a decrease in cooling capacity in general. This gives rise to a natural limitation of the possibility of developing and improving the irrigation system of the cooling tower.

Closest to the proposed invention is a spray tower containing a casing with air inlets in the lower part, a water distribution system with nozzles directed upward by the outlet openings, and located symmetrically to the longitudinal axis of the exhaust tower, a catchment basin located under the cooling tower housing, an exhaust device made in the form fan and located above the housing, a water trap device and a dropping device in the form of a spatial structure (RF patent N 2183005, IPC F28C 1/00, published on May 27, 2002).

The disadvantage of the prototype patent, where water is cooled from the surface of a small fraction droplet stream, is the relatively small range of hydraulic and thermal loads at which this type of cooling tower effectively cools the circulating water flow. A decrease in the thermal and hydraulic loads from the calculated ones is associated with a decrease in the water pressure on the spray device, which leads to enlargement of drops, a decrease in the free water surface from which heat removal occurs, which ultimately reduces the cooling ability of the cooling tower.

The technical result to which the invention is directed is to increase the active region of the tower without increasing aerodynamic drag.

To achieve this technical result, in a combined cooling tower comprising a housing in the form of an exhaust tower with air inlets in the lower part or a fan housing, a water trap, a drainage basin located under the cooling tower housing, a water distribution system with spray nozzles, the outlet openings of which are directed upwards, and an irrigation system device spray nozzles, for example, involute type are located at a distance from the top of the irrigation device at a distance of 0.1-1.0 · h, where h - the height of the irrigation device, while the pressure of the water in front of the spray nozzle should be in the range of 0.2-1.0 atm.

Signs that distinguish the proposed tower from the closest known to it according to the patent of the Russian Federation No. 2183005 (prototype), characterize the presence of spray nozzles located at a distance from the top of the irrigation device at a distance of 0.1-1.0 · h, and the flow of water pressure to nozzles are in the range of 0.2-1.0 atm.

Due to the presence of these signs, a developed droplet stream is created, consisting of fine particles. Its cooling ability in the area of the spray plume is identical to the heat and mass transfer in the irrigation device. The formation of a droplet flow occurs due to spray nozzles of the involute type, oriented by the outlet section up. Due to the ejection effect, the air flow leaving the irrigation device is accelerated. When the vertical velocity of the droplet flow reaches zero, the droplets rush down, where they create aerodynamic resistance to the oncoming air flow of very small values. Hence, the region of the droplet flow is neutral in aerodynamic characteristics and active in heat and mass transfer parameters.

The proposed combined cooling tower is illustrated by a drawing, which shows a longitudinal section of the proposed combined cooling tower.

The combined cooling tower contains an exhaust tower (fan casing) 1, a water trap 2, a water distribution system 3, an irrigation device 4, air inlets 5, a drainage basin 6. The involute-type spray nozzles 7 of the water distribution system 3 are placed at a distance of 0.1-1.0 h from the upper boundary of the irrigation device 4.

Combined cooling tower operates as follows.

An exhaust tower (fan casing) 1 provides air draft that enters the combined cooling tower through the air inlet windows 5. Once in the area occupied by the irrigation device 4, the air flow equalizes its velocity field, and there is active heat removal. Next, the air is directed through a water distribution system 3, equipped with spray nozzles 7, a water trap 2 and is released into the atmosphere. Through the water distribution system 3, hot circulating water is supplied, which is sprayed upward by the directed outlet, spraying nozzles 7 into the stream of air coming from below cooled in the irrigation device 4. Here, the cooling of the hot circulating water takes place, and the more intensively, the greater the pressure of the water on the spray nozzles 7. The pressure of the water cooled before the spray nozzle 7 is in the range of 0.2-1.0 atm.

Hence, the aforementioned limitation of the altitude of the placement of the spray nozzles 7 is to provide as much pressure of the cooled water on them as possible, which creates an active region of the small fraction droplet stream.

The proposed combined cooling tower increases the cooling depth of circulating water by 2-4 ° C in comparison with the cooling level of traditional cooling towers with a film or drip-film irrigation device, which practically brings this cooling tower closer to the cooling towers in terms of cooling efficiency of circulating water. If deeper cooling of water for a particular power plant is not necessary, then by performing the combined heat and mass transfer in the tower, you can increase the unit productivity of tower or fan types by 20-30%. The implementation of the invention is not associated with additional capital investments in the estimate for the construction of a new or reconstruction of an existing cooling tower.

Claims (2)

1. Combined cooling tower, comprising a casing in the form of an exhaust tower with air inlet windows at the bottom, a water trap, a drainage basin located under the casing of the cooling tower, a water distribution system with spray nozzles, the outlet openings pointing upwards, an irrigation device, characterized in that the spray nozzles , for example, the involute type, are located at a distance from the top of the irrigation device at a distance of 0.1-1.0 · h, where h is the height of the irrigation device, and the pressure water in front of the spray nozzle is in the range of 0.2-1.0 atm. 2. The combined cooling tower according to claim 1, characterized in that the exhaust tower is made in the form of a fan casing.