MX2008010508A - Arrangement and method for cooling a solution - Google Patents

Abstract

The invention relates to a cooling equipment for cooling liquid, comprising:a cooling tower that is mainly cylindrical in the vertical direction, in which case the cooling air feed equipment and the exhaust air discharge equipment are arranged, with respect to the cooling tower, so that both the cooling air flowing direction from the inlet aperture to the cooling space and the exhaust air flowing direction from the discharge equipment is horizontal and parallel to the tangent of the outer surface of the cooling tower. The invention also relates to a method for cooling liquid.

Description

EQUIPMENT AND METHOD FOR COOLING A SOLUTION Field of the Invention The present invention relates to a device and a method, defined in the independent claims, for the cooling of a solution in a cooling tower.

BACKGROUND OF THE INVENTION When zinc is separated from an electrolytic solution containing zinc ions and sulfuric acid, the temperature of the electrolyte generally rises. Typically, for cooling solutions such as electrolyte, or an acidic solution containing slurries or metals, cooling towers are used where the cooling process is based on the evaporation of liquid droplets in the air flowing upwards from the drops of liquid that are going to be cooled. In general, the air flow is colder than the liquid flow, in which case the liquid that flows downwards is cooled due to the transfer of heat. Consequently, convection occurs in the cooling process, and droplets that move against the air flow are evaporated. Heat is emitted as the liquid is cooled in the cooling tower. In the cross section, the cooling towers are typically either hexagonal or quadrangular cylinders. The solution to be cooled is conducted to the tower in a known manner through the upper part thereof, and the cooling air is fed through the side of the cooling tower. During the cooling process, droplets containing particulate material are separated from the solution. Said droplets are separated from the gas contained in the hazardous particulate material in droplet separating devices prior to letting the gas out. The separated liquid is taken back to the cooling tower. During the cooling process, impurities are accumulated in the walls of the tower and on the floor as well as in the elements of the droplet separator, which creates the need for frequent maintenance procedures. When the cooling air is fed to the cooling towers horizontally at a point provided on the wall of the tower, problems result mainly due to a non-uniform distribution of the gas. When the gas is conducted horizontally to the tower, it must rotate 90 degrees to move in the vertical direction in the cooling tower. Both this fact and the large size of the fan that feeds the air with respect to the dimensions of the tower can result in an uneven distribution of the gas in the cooling space of the cooling tower. In addition, another problem has been how to ensure efficient recovery of the drops. Conventionally, drops are collected separated by separation devices that are placed horizontally against the flow. In said devices, the drops are captured on the surface of the strip-like structures, and the liquid circulated by gravity is directed against the gas flow back to the cooling tower. The higher the gas velocity, the more effectively the drops are separated. However, a disadvantage of the devices placed horizontally for the collection and separation of the drops is that the speed of the gas must be restricted, which reduces the efficiency of the cooling tower. In the planning of cooling towers, attention must be paid to the emissions discharged from them, because cooling towers are often significant sources of emissions in a process, for example in zinc plants. Similarly, when assessing the functionality of the cooling towers, attention should be paid to the maintenance procedures of these towers. Often the towers require several maintenance operations within a short period of time, therefore it is important that maintenance is carried out easily and quickly. The efficiency of a cooling tower can be improved by optimizing a uniform distribution of the cooling air. Conventionally, an attempt has been made to improve the distribution of the cooling air in the cooling towers by placing an obstacle in front of the opening of the cooling air supply in the vertical direction, in which case the direction of the air flow can be diverted further upwards. The publication of patent document CA 2271424 Al discloses a cooling tower for cooling liquid. In the equipment according to said publication, a multi-layered wall arrangement for a cooling tower is described, wherein the The wall consists of an external wall and a flexible internal wall permeable to air, in which case part of the air is injected through the pores arranged in the internal wall towards the cooling space, where it meets the liquid to be cooled. The objective of this arrangement is to eliminate accumulated deposits on the internal wall. However, an optimal cooling solution is not achieved by this equipment, due to the loss of pressure produced by the internal wall.

Objectives of the Invention The objective of the present invention is to eliminate some of the disadvantages of the prior art and obtain a new form for the cooling of liquids. A particular object of the invention is to introduce a new cooling equipment and method, in which case the cooling efficiency is increased both by the supply of cooling air to the cooling space and by the conduction of the air flowing out of the cooling space. the cooling tower both horizontally and tangentially with respect to the cooling tower. The essential novel features of the invention are apparent from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in greater detail with reference to the accompanying drawings, in which: Figure 1 illustrates a cooling equipment according to the invention. Figure 2 shows a cooling equipment according to the invention, seen in a cross-section of the configuration illustrated in Figure 1. Figure 3 illustrates a cooling equipment according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The invention has notable associated advantages. The invention relates to cooling equipment for cooling liquids, comprising: a cooling tower that is mainly cylindrical in the vertical direction, said cooling tower includes an external surface, an upper part of the cooling tower and a cooling tower. lower part which together define the cooling space; the air supply equipment of cooling comprises at least one entry opening in the external surface of the cooling tower; means for feeding the cooling air to the inlet opening and further to the cooling space of the cooling tower; the equipment for feeding the liquid comprises means, such as nozzles for liquids, for feeding the liquid to be cooled to the cooling space, discharge equipment for the air outlet, as well as means for removing the cooled liquid, in which case the cooling air supply equipment and the exhaust air discharge equipment are positioned, with respect to the cooling tower, so that both the cooling air flow direction from the inlet opening to the space of cooling, as the direction of flow of the exhaust air outside the discharge equipment, be horizontal and parallel with the tangent of the external surface of the cooling tower. By means of a cooling device according to the invention, an even distribution of the cooling air in the cooling zone is advantageously achieved, and the cooling process is improved. Feeding cooling air to the cooling space horizontally, preferably in the vicinity of the lower part of the cooling tower, and in parallel with the tangent of the external surface of the cooling tower, the component of the horizontal rotation speed of the air flow is simultaneously elevated. Thus, the residence time of the cooling air in the cooling space is increased, and consequently the cooling efficiency of the droplets of liquid flowing in the tower is improved. According to the invention, the outlet air discharge equipment comprises a housing element that includes at least four, preferably eight, outlet openings arranged vertically with respect to the horizontal cross section of the cooling tower. According to one embodiment of the invention, the outlet openings are positioned equidistantly in the housing element, in which case each plane parallel to the surface of the exit opening forms an equally large angle with the tangent of the external surface of the cooling tower. According to one embodiment of the invention, at each outlet opening, at least one droplet separator element is installed vertically for the separation of the liquid droplets from the outlet air. According to one embodiment of the invention, the droplet separating element is formed of at least two vertical plates with a corrugated profile, permeable to air and positioned adjacently. When air is also conducted out through the upper part of the cooling tower both horizontally and tangentially, it is possible to use separating devices installed vertically to separate the air and the drops contained therein, in which devices the return circulation The liquid flows perpendicular to the outlet air flow, which increases the gas velocity and improves the cooling efficiency. The droplet separating devices that are placed vertically with respect to the cooling tower are more effective than the separating devices placed horizontally. Using a cooling equipment according to the invention, the size of the cooling tower is markedly reduced, while the cooling efficiency is, however, increased. This brings advantageous savings in the expense of cooling tower materials. In addition, the cooling arrangement according to the invention makes the maintenance operations of the liquid feeding equipment and the exhaust air discharge equipment easier due to the practical positions of these. According to an advantageous embodiment of the invention, the ratio of the height of the outlet opening to the height of the cooling tower in the vertical direction is 1: 5, in which case optimal cooling efficiency is achieved . Figure 1 illustrates a cooling equipment 1, according to the invention for cooling liquids, such as electrolyte. Figure 2 shows a cross section of the embodiment of Figure 1, seen according to direction A. Figure 3 illustrates a cooling equipment according to the invention, seen in three-dimensional form. The cooling equipment 1 comprises a cooling tower 2 with an essentially cylindrical cross section in the vertical direction, provided with an external surface, i.e. the wall 3, an upper part 4 and a lower part 5 of the cooling tower, which together define the cooling space 6. The shape of the cooling tower 2 is advantageously a cylinder in the vertical direction, but may also have a shape in which the cross section becomes wider in the part upper 4, in which case a wider acceleration area is achieved for the air flow before it leaves from the cooling tower. The upper part and the lower part are closed while cooling is in operation. The external surface 3 of the cooling tower is typically made of glass fiber or a corresponding material. He cooling air 7 is fed to the cooling space 6 of the cooling tower 2 horizontally with respect to the cooling tower, and in parallel with the tangent 15 of the external surface of the cooling tower, by means of the cooling equipment. cooling air feed 8, comprising at least one inlet opening 9 disposed on the external surface 3 of the cooling tower, and means such as a fan for feeding cooling air additional to the cooling space 6 of the tower Cooling. There may also be several entrance openings arranged at different points on the external surface 3. The liquid 10 to be cooled is fed by means of the liquid feeding equipment 1 1, which comprises means such as for example liquid nozzles 24 for injection of the liquid 10 to be cooled inside the cooling space 6. Droplets of liquid to be cooled, such as electrolyte droplets, are moved in the cooling tower against the air flow 20 advancing upwards vertically, in which case the water is evaporated from these. In the cooling space of the cooling tower, the air flow becomes turbulent, and its speed in the horizontal direction increases. The smaller droplets are separated from the cooled droplets that flow downwards, droplets which are led to the outlet air discharge equipment 12, which is in communication with the cooling space 6. In the air discharge equipment of the outlet 12, the liquid drops are separated from the air and can be recirculated to be cooled in the cooling tower 2. The cooled liquid is removed for example through an outlet 13 provided in the lower part 5 of the cooling tower. cooling, or through an overflow opening 25, and sent to further processing. The outlet air discharge device 12 according to the invention comprises a housing element 19 at least partially hollow, provided according to the example with eight outlet openings 16 positioned vertically with respect to the horizontal cross section of the cooling tower 2. When the outlet openings are positioned in the vertical direction relative to the outlet air flow 14, the outlet air flow 14 is allowed to be discharged horizontally and in parallel with the tangent 15 of the external surface 3 of the cooling tower. The outlet openings 16 are positioned equidistantly in the housing element 19, in which case each plane 17 parallel to the surface of the outlet opening forms an angle B likewise. large with the tangent 15 of the external surface of the cooling tower 2. The ratio of the vertical height 22 of the outlet opening 16 with respect to the vertical height 23 of the cooling tower is preferably 1: 5. Naturally the number, height, position, and angle B of the outlet openings 16 can vary depending on the amount of the liquid to be cooled and the cooling air being fed, as well as the cooling demand. Each outlet opening 16 is provided with a droplet separating element 18 placed vertically in parallel with the surface of the outlet opening, separating element 18 which separates the liquid droplets from the exhaust air 14, and the droplets can be recirculated back to the cooling tower. According to an example, the droplet separating element 18 is formed of at least two vertical plates with a corrugated profile, permeable to air and arranged in an adjacent manner. A maintenance level 21 can be installed to surround the cooling tower 2, in the vicinity of the upper part 4 thereof, maintenance level 21 from which the maintenance of the cooling equipment can be easily carried out. For a person skilled in the art, it is obvious that the various different embodiments of the invention are not restricted to the examples described above, but may vary within the scope of the appended claims.

Claims (8)

1. Claims 1. A cooling equipment for cooling liquids, which comprises: - a cooling tower that is mainly cylindrical in the vertical direction, having an external surface, an upper part and a lower part of the cooling tower, which define the space of cooling, - a cooling air supply equipment, comprising at least one inlet opening disposed on the external surface of the cooling tower, means for feeding the cooling air to the inlet opening and further to the space of cooling of the cooling tower, - equipment for feeding the liquid, comprising means for feeding the liquid to be cooled to the cooling space, - equipment for the discharge of the exhaust air, - as well as means for removing the cooled liquid, characterized in that the equipment for the supply of cooling air and the equipment for the discharge of the The outlet air is positioned, with respect to the cooling tower, so that both the direction of the cooling air flow from the inlet opening to the cooling space, and the direction of flow of the outlet air from the discharge equipment are horizontal and parallel to the tangent of the external surface of the cooling tower, and in which the outlet air discharge equipment includes a housing element, provided with at least four outlet openings positioned vertically with respect to the horizontal cross-section of the cooling tower
2. 2. A cooling equipment, according to claim 1, characterized in that the housing element of the exhaust air discharge equipment is provided with eight outlet openings, arranged equidistantly in the housing element, so that each plane parallel to the surface of the exit opening forms an equally large angle with the surface tangent and external cooling tower.
3. 3. A cooling device, according to claim 1 or 2, characterized in that at each outlet opening there is installed in the vertical direction at least one droplet separating element for separating the drops of liquid from the outlet air.
4. 4. A cooling equipment, according to claim 3, characterized in that the droplet separating element is formed by at least two vertical plates with a corrugated profile, permeable to air and installed in an adjacent manner.
5. 5. A cooling equipment, according to any of the preceding claims, characterized in that the outlet air discharge equipment is placed in the upper part of the cooling tower, and the cooling air supply equipment is placed in the neighborhood of the bottom.
6. 6. A cooling device, according to claim 1 or 2, characterized in that the proportion of the height of the outlet opening with respect to the height of the cooling tower in the vertical direction is advantageously 1: 5.
7. 7. A cooling equipment according to claim 1, characterized in that the liquid feeding equipment comprises at least one nozzle for liquids, installed in the upper part of the cooling tower, below the air discharge equipment. of exit.
8. 8. A method for cooling liquids in a cooling equipment, which comprises: a cooling tower that is mainly cylindrical in the vertical direction, having an external surface, an upper part and a lower part of the tower cooling, which define the cooling space, - a cooling air supply equipment, comprising at least one inlet opening placed on the external surface of the cooling tower, - means for feeding the cooling air to the inlet opening and then to the cooling space of the cooling tower, - a device for feeding the liquid, comprising means for feeding the liquid, to be cooled to the cooling space, - a device for discharge of the exhaust air, - as well as means (13) for removing the cooled liquid , characterized in that the cooling air is fed horizontally and in parallel with the tangent of the external surface of the cooling tower to the cooling space, where the cooling air meets the liquid fed in. against the current, air which flows out of the cooling space, so that the direction of flow is horizontal and parallel to the tangent of the external surface of the cooling tower and the exhaust air is led to the discharge equipment , where it is taken to the discharge through at least four exit openings equipped with a droplet separator element placed in the vertical direction, in which case the air separates the liquid, which is then recirculated back to the tower Cooling.