cooling tower

Abstract

A cooling tower is disclosed comprising a chamber defined by a peripheral wall and a top wall, wherein the top wall defines an outlet of the cooling tower; a gas inlet formed in the peripheral wall for introducing a gas into the chamber; one or more nozzles configured to spray a liquid to be cooled into the chamber; a fluid outlet for allowing cooled liquid to exit the chamber; and one or more mist eliminators arranged within the chamber. The mist eliminators are arranged such that fluid moving from within the chamber to the outlet passes substantially radially inwardly through the one or more mist eliminators towards a centreline of the cooling tower before reaching the outlet. A method of cooling a liquid in a cooling tower and a method of cleaning a cooling tower are also disclosed.

Description

Technical Field

[0001] This disclosure relates to a cooling tower, a method of using the cooling tower to cool liquid, and a method of cleaning the cooling tower. Background Technology

[0002] Cooling towers are widely used in industry to cool fluids. Some cooling towers are essentially passive, in which airflow from the surrounding atmosphere draws in air near the base of the tower and then heats it inside. The heated air rises through the tower and exits from the top. There are "wet" cooling towers, where the air comes into direct contact with the fluid to be cooled. There are "dry" cooling towers, where air passes through a heat exchanger through which the liquid to be cooled flows.

[0003] In the field of hydrometallurgy, electrolytes or acidic solutions containing slurries or metals require cooling. For example, the separation of zinc from an electrolyte containing zinc ions and sulfuric acid is known. During the separation process, the temperature of the electrolyte typically rises, and then cooling is necessary.

[0004] WO 2007 / 096457 A2 discloses a cooling tower in which cooling air is introduced into the tower via a fan near the base. The cooling air typically enters the tower horizontally and circulates within it. Nozzles are positioned near the top of the tower, which spray the liquid to be cooled into the tower, causing the droplets to mix with the air and cool through evaporation.

[0005] Eight demisters are arranged near the top of the cooling tower, in a manner that allows fluid passing through them to exit horizontally from the top of the tower. The demisters remove water droplets suspended in the air, as well as any impurities contained within those droplets. Therefore, the demisters essentially purify the fluid passing through them, thereby limiting the overall emission of impurities (which may be toxic in some cases) from the cooling tower.

[0006] During operation, impurities in the liquid accumulate on the chamber walls and in the demister. This necessitates relatively frequent cleaning and is often the primary limiting factor in determining maintenance cycles. In other words, these are the parts of the cooling tower that require the most frequent maintenance, such as monthly. To perform this maintenance cleaning, the demister must be sprayed with a pressure hose to wash away the accumulated impurities. The chamber walls and floor must also be sprayed with a pressure hose, which typically requires removing the demister to allow maintenance personnel access to the interior of the chamber. Summary of the Invention

[0007] According to a first aspect, a cooling tower is provided, comprising: a chamber defined by a peripheral wall and a top wall, wherein the top wall defines an outlet of the cooling tower; a gas inlet formed in the peripheral wall for introducing gas into the chamber; one or more nozzles configured to spray liquid to be cooled into the chamber; a fluid outlet for allowing cooled liquid to exit the chamber; and one or more demisters arranged within the chamber such that fluid moving from the chamber to the outlet passes substantially radially inward through the one or more demisters toward the centerline of the cooling tower before reaching the outlet.

[0008] The liquid is cooled by gas from the gas inlet. The liquid is cooled primarily through evaporation. Therefore, the gas and liquid mix to form a fluid mixture, which then passes through a demister. The demister removes the cooled liquid from the fluid mixture, ensuring that the gas exiting the cooling tower through the outlet is essentially liquid-free. This liquid may be toxic or environmentally unfriendly.

[0009] The platform can be located within a chamber, wherein at least one of one or more demisters is arranged such that a first end of the demister is connected to the platform, and a second end of the demister is connected to the top wall. Therefore, the platform provides a convenient installation location for the demisters. The platform also provides a standing area for maintenance personnel when servicing the cooling tower.

[0010] The fluid outlet can be located at the base of the cooling tower. The base can be integrally formed with the rest of the cooling tower. That is, the base can be attached to or integrally formed with the peripheral wall. Alternatively, the peripheral wall of the cooling tower can be installed on a pre-existing base on site. For example, the peripheral wall can be installed on a concrete platform.

[0011] Alternatively, the fluid outlet can be an overflow fluid outlet located in the tower's peripheral wall. In the latter case, during operation, a coolant pool exists at the bottom of the tower, and as additional liquid is injected into the chamber and cooled, overflow flows into this overflow fluid outlet.

[0012] Cooling towers may include fans, compressors, blowers, and / or compressed gas sources connected to a gas inlet for pressurizing gas (preferably air) into a chamber. This increases the cooling capacity of the tower by increasing the airflow entering the cooling tower, rather than relying on, for example, natural airflow and / or convection.

[0013] For at least one or each of the demisters, the demister may be located radially inside the peripheral wall, such that a gap exists in the radial direction between the radially outer edge of the demister and the peripheral wall. In use, the fluid velocity in the chamber may be greater in the horizontal direction than in the vertical direction. Therefore, the fluid in the gap can pass through the demister in the horizontal direction, thus utilizing the larger horizontal component of the flow velocity. Optionally, several or even all of one or more demisters may be positioned in this manner.

[0014] The arrangement of the demister can take advantage of the larger horizontal velocity component of the fluid in the chamber and ensure that more / faster fluid flows through the demister, thereby increasing the capacity of the cooling tower.

[0015] For each demister in a demister, or for each demister in general, a demister may include a plurality of spaced-apart corrugated sheets of material.

[0016] The corrugated material plates force the fluid through the demister between the plates, creating a tortuous or serpentine path. This change in direction within the path causes a decrease in flow velocity, allowing entrained droplets to drip from the fluid flow, either directly from the demister or adhering to the plates and then flowing out of the demister. In this way, the demister removes liquid from the fluid flowing through it. This liquid can then be returned to the chamber.

[0017] At least one or each of the demisters can define a predetermined flow direction for fluid to flow through the demister. One or more corrugated plates may also include one or more hooks, wherein each hook extends in a direction opposite to the predetermined flow direction, such that a dead end is formed in the flow direction in which the hook connects to the plate.

[0018] One or more hooks can increase the demisting effect of a demister by forcing a portion of the fluid flowing through the demister to stop completely at or near the dead zone.

[0019] At least one or each of the demisters may be arranged parallel to the centerline of the cooling tower, which extends from the base to the top wall. When the cooling tower is installed such that the top wall is vertical to the perimeter wall, the centerline will be the vertical centerline of the cooling tower.

[0020] This allows the fluid flowing through the demister to flow entirely or almost entirely in a horizontal direction. Therefore, this orientation can take advantage of the higher horizontal flow velocity of the fluid in the chamber.

[0021] Alternatively, for at least one of the one or more demisters, the demister may be arranged at an angle to the centerline of the cooling tower extending from the base to the top wall, such that the base end of the demister near the base of the cooling tower is closer to the centerline than the opposite top end of the demister near the top wall. Optionally, several or even all of the one or more demisters may be arranged in this manner.

[0022] This angle can be greater than zero degrees and less than 20 degrees, preferably less than 15 degrees. That is, at least one or each of the demisters can be tilted outwards relative to the centerline of the tower. This arrangement makes it easier to insert and remove the demisters from the tower, for example, during maintenance. For instance, when a demister is removed by a crane extending through the outlet, removal of (one or more) demisters may be easier if the demisters are tilted upwards to a certain extent. Therefore, (one or more) demisters can also be held in place relative to the platform by gravity.

[0023] The outlet in the top wall can be vertically oriented, allowing the gas exiting the tower to flow vertically. This provides a simple method, for example, by providing an outlet in the top wall to allow gas to exit the cooling tower. Allowing the gas to exit the cooling tower vertically avoids the recirculation pattern where warm air exiting the cooling tower flows downwards towards the inlet. This recirculation undesirably reduces the cooling efficiency of the tower by increasing the temperature of the medium (i.e., the gas) used in the cooling tower.

[0024] The platform can be connected to the top wall via one or more supports and / or beams. The one or more supports and / or beams can be configured to receive a demister or each demister for mounting the demister or each demister in the cooling tower.

[0025] In other words, the struts and / or beams can together provide one or more frames to receive one or more demisters.

[0026] Alternatively or additionally, the platform may be connected to the perimeter wall by one or more supports and / or beams. A support is a component configured to resist longitudinal compression and, in some cases, longitudinal extension (tension). A beam is a component configured primarily to resist loads transversely across the beam's axis. In some cases, depending on its intended use, the same object may be used as either a beam or a support.

[0027] Cooling towers can be configured for hydrometallurgical applications. For example, components can be made of suitable materials to avoid corrosion and / or thermal damage from the liquid being cooled within the tower. The selection of suitable materials will depend on the specific application of the given tower, such as whether the liquid being cooled is highly alkaline, highly acidic, or particularly hot upon entering the tower.

[0028] According to a second aspect, a method for cooling a liquid in a cooling tower according to a first aspect is provided. The method includes: introducing a gas (optionally air) into a chamber through a gas inlet; spraying the liquid to be cooled into the chamber from one or more nozzles; causing the gas from the gas inlet to cool the liquid and mix with the liquid to form a mixed fluid; and passing the mixed fluid through one or more demisters to reduce or eliminate the liquid in the mixed fluid.

[0029] The gas cools the liquid, and then a demister removes the liquid entrained in the gas. The removed liquid can be recirculated back into the chamber for further cooling. Demister removal may be particularly important in cases where the liquid is toxic or environmentally unfriendly.

[0030] According to a third aspect, a method for cleaning a cooling tower according to a first aspect is provided. The method includes: spraying one or more demisters with a high-pressure liquid jet; and / or removing one or more of the one or more demisters to allow access to a chamber and spraying the walls of the chamber with a high-pressure liquid jet. Optionally, the liquid is water. Optionally, the liquid jet includes a cleaning agent. The wall cleaned in this manner can be a peripheral wall, a top wall, or both a peripheral wall and a top wall.

[0031] The platform provides maintenance personnel with a convenient standing position relative to one or more demisters. That is, workers can stand directly in front of the demister, for example, and spray it with a pressure hose. Similarly, when the demister is moved away from its position between the platform and the top wall, workers on the platform can directly see the chamber and spray it from the platform to remove any residue. Attached Figure Description

[0032] Figure 1 A three-dimensional view of a known cooling tower is shown; Figure 2 It shows Figure 1 A sectional perspective view of a known cooling tower; Figure 3 A schematic diagram of a cross-section of the cooling tower is shown; Figure 4 A sectional perspective view of the cooling tower is shown; Figure 5 A sectional perspective view of the demister is shown; Figure 6 The top of the cooling tower is shown. Detailed Implementation

[0033] Figure 1 and Figure 2A known design of a cooling tower 10 is shown. The cooling tower 10 includes a wall 12 defining a chamber 13. The wall 12 generally defines a generally cylindrical chamber 13. A gas inlet 14 is located near the base of the cooling tower 10, and a fan 15 is used to draw gas (typically air) from the atmosphere surrounding the cooling tower 10 into the chamber 13. The upper portion 16 of the cooling tower 10 has a plurality of demisters 18a, 18b, which are arranged such that fluid, after passing through the demisters 18a, 18b arranged circumferentially around the cooling tower 10, is discharged radially outward from the centerline Y of the cooling tower 10 in a generally horizontal direction. A conduit 20 is provided to deliver liquid to be cooled to the upper portion 16 of the cooling tower, and thereby to a plurality of nozzles 24 located within the chamber 13. The nozzles 24 are located at a vertical level below the demisters 18a and are generally oriented downward at an angle, such that the liquid is widely sprayed towards the center of the chamber 13.

[0034] In operation, the liquid to be cooled is pumped to nozzle 24 through liquid pipe 20. The liquid is injected into chamber 13, moves generally downward, and mixes with the rising airflow (which may be air from the atmosphere) from gas inlet 14. As the liquid and gas mix, turbulence is generated as the gas cools the liquid. Some liquid evaporates into the airflow, while some liquid remains suspended in the airflow as droplets, forming a mixed fluid. The mixed fluid flows through demisters 18a and 18b, moving in a generally horizontal direction, which is radially outward from the vertical centerline Y of the cooling tower 10.

[0035] Demisters 18a and 18b typically comprise multiple spaced-apart corrugated plates, with the corrugations on adjacent plates aligned with each other. This forces the fluid through the demister to follow a serpentine path, significantly reducing the fluid velocity. This velocity reduction causes suspended droplets to separate from the fluid flow and form on the plates. The droplets can then flow out of the demister.

[0036] Figure 3A novel design for a cooling tower 100 is depicted. The cooling tower 100 includes a peripheral wall 112 defining a chamber 113 of the cooling tower. The peripheral wall 112 may define a cylindrical chamber 113, but other shapes are also contemplated, such as chambers having a square, rectangular, hexagonal, or elliptical cross-sectional shape. A top wall 122 of the chamber 113 defines the top of the chamber 113. An outlet 123 is provided on the top wall 122 for allowing fluid to flow out of the chamber 113. The outlet 123 can be of any shape, including, for example, circular, hexagonal, or square. A base 125 of the chamber 113 defines the bottom of the chamber 113. The base 125 of the chamber 125 includes a liquid outlet 126 for allowing liquid to flow out of the chamber 113. The base 125 may be part of the cooling tower 100. Alternatively, the peripheral wall 112 and top wall 122 of the cooling tower can be constructed on existing space on site (e.g., a concrete platform), thus enclosing the bottom of the cooling tower and serving as the base of the cooling tower 100 after construction. During assembly, the cooling tower 100 is arranged vertically such that the centerline X of the cooling tower extending from the base 125 to the top wall 122 is vertical, i.e., vertical relative to gravity.

[0037] The peripheral wall 112 can be made of any suitable material. The top wall 122 can be made of any suitable material. Some suitable materials include fiberglass, aluminum, (stainless) steel, and combinations thereof. The base 125 can be a separate material, for example, it can be concrete for mounting the peripheral wall 112 of the cooling tower 100. Alternatively, the base 125 can be made of the same material as the peripheral wall 112.

[0038] Gas inlet 114 is positioned near the base 125 of cooling tower 100, passing through the peripheral wall 112, and fan 115 is used to draw gas (typically air) into chamber 113. As described below, the air is used to cool the liquid to be cooled. Although only one gas inlet 114 is shown, multiple gas inlets may be provided near the base of cooling tower 100.

[0039] Platform 119 is disposed within chamber 113, facing the upper end of chamber 113. That is, platform 119 is located vertically within chamber 113 between base 125 and top wall 122, and is generally closer to top wall 122 than base 125. In other words, platform is located in the upper part of cooling tower 100.

[0040] Platform 119 is spaced apart from peripheral wall 112, but may be connected to peripheral wall 112, for example, via supports and / or beams. Alternatively or additionally, platform 119 may be connected to top wall 122, for example, via supports and / or beams. One or more demisters 118 are arranged around platform 119, typically extending between platform 119 and top wall 122. In one example, eight demisters 118 are arranged circumferentially around platform 119. In other examples, two to ten demisters 118 are provided. These exemplary demisters 118 essentially extend the entire distance between platform 119 and top wall 122. If supports are present connecting platform 118 to top wall 122, these supports may also provide mounting points for demisters 118. That is, supports / beams may typically define a frame for each demister to be installed. Platform 119 is solid, so fluid cannot pass through platform 119 itself.

[0041] One or more demisters 118 are located radially inside the peripheral wall 112 of the cooling tower 100. The one or more demisters 118 are arranged such that fluid discharged from the outlet 123 must first pass through one or more demisters 118. That is, each demister is arranged in a chamber such that fluid moving from the chamber 113 to the outlet 123 passes through the demister substantially radially inward toward the centerline X of the cooling tower before reaching the outlet 123.

[0042] One or more nozzles 124 are disposed within chamber 113. These are typically arranged at or below the level of platform 119, but may be located at a higher position, provided that their spray does not directly impinge on one or more demisters 118. The nozzles 124 are configured to spray liquid to be cooled into chamber 113. There are no particular limitations on the liquid to be cooled; it can be any liquid, including, for example, water, acid, acidic solutions, electrolytes, or neutral solutions. The liquid can be supplied at any temperature. Typically, cooling tower 100 can be used to cool liquids with temperatures between 25°C and 95°C. The temperature of the cooling liquid discharged through liquid outlet 123 can be between 15°C and 75°C. The temperature of the gas entering gas inlet 114 can be ambient atmospheric temperature, and therefore typically between -35°C and 45°C. The temperature of the gas discharged from outlet 123 may be between 0°C and 65°C.

[0043] In use, airflow A1 is drawn into chamber 113 via inlet 114 near base 125 of chamber 113. This airflow is typically drawn from the atmosphere surrounding cooling tower 100, but in principle it can be any gas, including, for example, gas from a compression source such as a compressed air tank or compressor.

[0044] When airflow A1 enters chamber 113, it is typically horizontal. Gas inlet 114 can be arranged such that the centerline of its horizontal extension does not intersect the vertical centerline X of the tower. That is, the inlet may not point directly to the centerline of the cooling tower 100. In this way, gas inlet 114 injects gas into chamber 113, causing the gas to move circumferentially within chamber 113. Liquid flow B1 to be cooled is sprayed into chamber 113 from nozzle 124. The downward-falling liquid flow B1 mixes with airflow A1, creating turbulence of mixed fluid A2 within chamber 113. As the mixed fluid flow becomes turbulent, its velocity in the horizontal direction (i.e., in the plane perpendicular to the centerline X) increases.

[0045] In turbulent flow A2, the liquid to be cooled is primarily cooled by evaporation, but can also be cooled by the gas through conduction and convection. The strong airflow and turbulence help break down the water droplets ejected from nozzle 124 into smaller droplets, further improving the tower's cooling efficiency. The cooled liquid eventually drips from the base 125 of the cooling tower 100, and the cooling liquid flow B2 is discharged from the cooling tower 100 via liquid outlet 126. Figure 3 In the diagram, liquid outlet 126 is shown as a vertically oriented outlet formed in the base 125 of chamber 113. In an alternative design, liquid outlet 126 may be generally horizontally oriented and formed in the peripheral wall 112 of cooling tower 100, near the base 125 of cooling tower 100, i.e., arranged as an overflow outlet.

[0046] If necessary, the liquid discharged from outlet 126 can be recirculated through cooling tower 100. That is, this portion of liquid can be recirculated through the tower by being fed directly into one of the nozzles 12, or the liquid can be mixed with the stream of (hotter) liquid to be cooled that is normally supplied to nozzle 124.

[0047] Turbulent flow A2 rises toward one or more demisters 118. As previously described, the turbulent flow results in an increase in velocity in the horizontal direction. The fluid is a mixture of gas (e.g., air), evaporating liquid, and droplets, forming a fluid flow A3 that passes through the demisters in a generally horizontal direction along the centerline X of the cooling tower 100. Therefore, the specific orientation of the demisters 118 allows them to utilize the high horizontal velocity of the turbulent flow as it moves out of the cooling tower 100.

[0048] In the case of multiple demisters 118, fluid in any given section will typically pass through only one of the demisters 118 before exiting the cooling tower 100, but the arrangement of the demisters 118 makes it necessary for all or substantially all fluid in the discharge chamber 113 to pass through at least one demister 118.

[0049] The demister 118 comprises a plurality of spaced-apart corrugated plates, wherein the corrugations on adjacent plates are aligned with each other. This shape forces the fluid passing through the demister to take a serpentine path, which significantly reduces the fluid velocity. This velocity reduction causes suspended droplets to separate from the fluid flow and form on the plates. The droplets can then flow out of the demister 118.

[0050] Each demister 118 is arranged such that the fluid flowing through it flows approximately horizontally. When droplets fall from the airflow in a demister oriented in this manner, they typically fall perpendicular to the flow direction under gravity. This helps prevent the droplets from slowing down the flow of subsequent fluid entering the demister. In contrast, in a vertically oriented demister, the fluid typically flows vertically upwards through the demister, and droplets falling from the airflow fall in the opposite direction to the airflow under gravity. This undesirably reduces the flow velocity of fluid entering after the droplets and also increases the chance of the droplets being re-entrained in the airflow. The efficiency of a horizontally oriented demister can be twice that of an equivalent vertically oriented demister. That is, it can demist twice the amount of mixed fluid per unit time compared to a vertically oriented demister.

[0051] After passing through one or more demisters 118, the fluid flow A4 changes direction and moves vertically upward, exiting the cooling tower 100 through outlet 123. During this stage, the fluid, after passing through one or more demisters 118, is almost entirely or entirely a gas heated in contact with the liquid to be cooled. This gas is then discharged into the atmosphere.

[0052] exist Figure 1 and Figure 2 In the known cooling tower 10 shown, the demister 18 is positioned more radially outward compared to the wall 12 of the cooling tower 10. This means that the effective floor area of ​​the cooling tower 10 is larger than the floor area measured on the ground around the wall 12. Furthermore, the fluid is discharged from the cooling tower 10 in a generally horizontal direction. Figure 3 and Figure 4 In the cooling tower 100, the fluid is discharged from the cooling tower 100 in a generally vertical direction, but still passes through the demister 118 in a generally horizontal direction. Therefore, this structure maintains the aforementioned higher efficiency of the horizontal demister compared to the vertical demister.

[0053] In comparison, Figure 3 and Figure 4 The cooling tower 100 shown can have an effective footprint entirely defined by the wall 12 (plus a small footprint for accommodating the gas inlet 114). Therefore, multiple cooling towers 100 can be placed closer together than known cooling towers 10.

[0054] For example, according to Figure 1 and Figure 2The original design involved arranging four cooling towers 10 in a square configuration, each with a cylindrical chamber 13 6m in diameter. This required a 22m x 22m floor space at the installation site to accommodate the larger upper sections 16 of two of the cooling towers 10 and provide sufficient spacing between them. In contrast, if the newly designed four cooling towers 100 were arranged in a square configuration, each also with a 6m diameter chamber, only a 12m x 12m floor space would be needed at the installation site. Therefore, the new design saves significant space for a given cooling capacity, whether for a single cooling tower or multiple tower installations.

[0055] The smaller overall size of the newly designed cooling tower 100 (due to the absence of the larger upper part 16 mentioned above) not only achieves equivalent cooling capacity but also reduces material costs and simplifies the structure.

[0056] Further investigation revealed that the warm gas flowing out of the cooling tower 10 at approximately the same horizontal level causes air circulation outside the cooling tower 10, resulting in the air drawn in at inlet 14 being hotter than under other conditions. This reduces the cooling efficiency of the tower 10.

[0057] when Figure 3 and Figure 4 When the fluid flow A4 from the cooling tower 100 is sprayed vertically, the aforementioned undesirable air circulation outside the tower can be significantly reduced. Therefore, in this new design of the cooling tower 100, the temperature rise of the gas (air) entering the inlet 114 is also significantly reduced.

[0058] Figure 5 A perspective view of a demister 118 that can be used in a cooling tower 100 is shown. The demister 18 includes a plurality of spaced-apart plates 40, 42, typically arranged in a frame that holds the plates in a proper spaced relationship with each other. Figure 5 The image shows two plates 40, 42, but typically a single demister will comprise ten to fifty (10-50) such plates. Each demister 118 is formed of multiple plates and generally has a roughly rectangular shape that can be defined by a frame. Each plate 40, 42 has a corrugated profile and is generally arranged parallel to each other, such that the plates 40, 42 define multiple serpentine flow paths through the demister 118. A slit is defined between each pair of adjacent plates. Figure 5 In the example shown, when the demister 18 is installed in the cooling tower 100, the slit extends vertically. In another example, not shown, the plate can be arranged such that when the demister 18 is installed in the cooling tower 100, the slit extends horizontally. In both cases, the airflow through the demister is primarily in the horizontal plane. In the latter case, the fluid in the vertical plane will be slightly deflected due to the corrugation of the plate. However, the overall direction of the fluid flow from one side of the demister to the other is horizontal.

[0059] The demister 118 can preferably be arranged such that the slit extends vertically when the demister is installed, allowing droplets to fall freely to the bottom of the demister under gravity. Fluid flow A3 as... Figure 5 As shown by the arrow in the image.

[0060] The fluid entering the demister 118 contains gas from chamber 113, evaporated liquid, and suspended droplets. As the fluid flows between the corrugated plates 40, 42, it is forced to change direction and reduce velocity. This causes droplets to impact the plates 40, 42 and adhere to them through surface tension. This also causes the suspended droplets to fall from the airflow toward the base of the demister 118. The droplets then drip and / or flow down along the plates 40, 42 and, depending on the arrangement of the demister 118, can be collected and recycled back to chamber 113, or they can fall directly back into chamber 118, i.e., the droplets fall from the bottom of each plate 40, 42.

[0061] Each demister plate 40, 42 may have one or more hooks 40a, 40b, 42a, 42b facing the fluid flow A3. Each hook may be part of a wall facing the fluid flow A3, such that the fluid flowing into the hook reaches a dead zone. Droplets may preferentially accumulate in the hooks 40a, 40b, 42a, 42b.

[0062] Figure 3 and Figure 4 The demister 118 shown is arranged vertically in the cooling tower such that the top of the given demister 118 (which is connected to the top wall 122) is directly and vertically above the base of the demister 118 (which is connected to the platform 119).

[0063] Figure 6 Another design for the cooling tower 100 is shown, in which the demisters 118 are arranged at an angle to the vertical. In this design, the demisters 118 cumulatively define a truncated conical shape, with the narrower end of the truncated cone closer to the base 125 and the wider end closer to (or directly adjacent to) the top wall 122. In other words, each demister 118 can be said to be “tilted outward” from the platform 119. The fluid flow A3 can still flow through these demisters substantially in a horizontal plane. Therefore, this design also takes advantage of the higher horizontal velocity of the fluid flow in the chamber 113.

[0064] To maintain the cooling tower 100, a worker can climb down from the top wall 122 to platform 119, where they are essentially surrounded by demisters 118. From this position, the worker can use a pressure hose to spray the demisters 118 for cleaning. From this position, the worker can remove one or more demisters 118 (optionally with the assistance of a crane) to expose the chamber 113. The worker can then use a pressure hose to spray the walls of chamber 113 for cleaning. Accessing the demisters from platform 119 in this manner is much easier and safer than accessing them from above (i.e., from the platform above the demisters) as described in WO 2007 / 096457 A2.

[0065] The curtain (not shown) can be installed on the radially inner surface of the peripheral wall 112, or suspended radially inward from the wall, so that the liquid does not directly contact the wall but contacts the curtain. The curtain can be replaceable. The curtain can be non-load-bearing. Compared to the wall material, the curtain can be made of a material more resistant to liquid corrosion. The appropriate material for the curtain can be selected based on the intended use of the cooling tower 100 (i.e., what liquid the cooling tower will cool).

Claims

1. A cooling tower, comprising: The chamber is defined by its peripheral walls and roof wall. The top wall defines the outlet of the cooling tower; A gas inlet, formed in the peripheral wall, is used to introduce gas into the chamber; One or more nozzles configured to spray the liquid to be cooled into the chamber; A fluid outlet for allowing cooled liquid to drain from the chamber; and One or more demisters are arranged in the chamber such that fluid moving from the chamber to the outlet passes substantially radially inward toward the centerline of the cooling tower before reaching the outlet.

2. The cooling tower according to claim 1, comprising a platform located within the chamber, wherein, At least one of the one or more demisters is arranged such that a first end of the demister is connected to the platform, and a opposite second end of the demister is connected to the top wall.

3. The cooling tower according to claim 2, wherein, The platform is connected to the top wall by one or more pillars and / or beams, wherein, optionally, at least some of the one or more pillars and / or beams are configured to receive the demister or each demister for mounting the demister or each demister in the cooling tower.

4. The cooling tower according to claim 2 or 3, wherein, The platform is connected to the perimeter wall by one or more pillars and / or beams.

5. The cooling tower according to any one of the preceding claims, wherein, The fluid outlet is located at the base of the cooling tower; or the fluid outlet is an overflow fluid outlet located in the peripheral wall of the tower.

6. The cooling tower according to any one of the preceding claims, comprising a fan, compressor, blower and / or compressed gas source connected to the gas inlet for pressurizing gas, preferably air, into the chamber.

7. The cooling tower according to any one of the preceding claims, wherein, For at least one or each of the demisters, the demister is located radially inside the peripheral wall such that a radial gap exists between the radially outer edge of the demister and the peripheral wall.

8. The cooling tower according to any one of the preceding claims, wherein, For at least one or each of the demisters, the demister comprises a plurality of spaced-apart corrugated material plates.

9. The cooling tower according to claim 8, wherein, The demister or each demister defines a predetermined flow direction for fluid to flow through the demister, and wherein one or more corrugated plates further include one or more hooks extending in a direction opposite to the predetermined flow direction, such that a dead zone is formed in the flow direction in which each hook connects to the plate.

10. The cooling tower according to any one of the preceding claims, wherein, At least one or each of the demisters is arranged parallel to the centerline of the cooling tower extending from the base to the top wall.

11. The cooling tower according to any one of claims 1-9, wherein, For at least one of the one or more demisters, the demister is arranged at an angle to the centerline of the cooling tower extending from the base to the top wall, such that the base end of the demister closer to the base of the cooling tower is closer to the centerline than the opposite top end of the demister closer to the top wall. Optionally, the angle is greater than 0 degrees and less than 20 degrees, preferably less than 15 degrees.

12. The cooling tower according to any one of the preceding claims, wherein, The outlet in the top wall is oriented such that the gas exiting the tower is discharged in a direction parallel to the centerline of the cooling tower.

13. The cooling tower according to any one of the preceding claims, wherein, The cooling tower is used in hydrometallurgy.

14. A method for cooling a liquid in a cooling tower according to any one of claims 1-13, the method comprising: Gas, optionally air, is introduced into the chamber through the gas inlet. The liquid to be cooled is sprayed from one or more nozzles into the chamber, such that gas from the gas inlet cools the liquid and mixes with it to form a mixed fluid. The mixed fluid is passed through one or more demisters to reduce or eliminate liquid in the mixed fluid.

15. A method for cleaning a cooling tower according to any one of claims 1-13, the method comprising: Spray the liquid stream onto the one or more demisters; and / or Remove one or more of the one or more demisters to allow access to the chamber, and spray the walls of the chamber with a liquid stream. Optionally, the liquid stream may include a cleaning agent, and / or be sprayed at high pressure, and / or the liquid may be water.

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