EP4782773A1

EP4782773A1 - Plume-abatement cooling tower and plume-abatement packing unit thereof

Info

Publication number: EP4782773A1
Application number: EP24881624.1A
Authority: EP
Inventors: Yong Li; Ping Jin; Changjian LIAO; Chenguang Li
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Priority date: 2023-10-23
Filing date: 2024-10-23
Publication date: 2026-07-29
Also published as: WO2025087259A1; CN119879589A

Abstract

The present disclosure relates to the field of cooling towers. Disclosed are a plume-abatement cooling tower and a plume-abatement packing unit thereof. The plume-abatement packing unit comprises a plurality of heat exchange sheets which are stacked, and dry cold airflow channels and wet hot airflow channels which are alternately distributed along a stacking direction and capable of realizing inter-wall heat exchange by means of the heat exchange sheets. The lower part of each heat exchange sheet is formed as an inverted trapezoidal structure, and adjacent heat exchange sheets are alternately sealed and connected at inclined edges on two sides of the inverted trapezoidal structure, so that dry cold airflow inlets in communication with the dry cold airflow channels and wet hot airflow inlets in communication with the wet hot airflow channels are alternatively formed on two opposite sides, and liquid collection outlets in communication with the wet hot airflow channels are formed at bottom short edges. Water collection and guide structures capable of guiding at least part of water carried in an airflow entering from the wet hot airflow inlets and/or generated by condensation of the airflow to the liquid collection outlets are formed on the sides of the heat exchange sheets facing the wet hot airflow channels. The plume-abatement packing unit can effectively improve the plume abatement effect.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefits of Chinese Patent Application No. 202311380107.9 filed on Oct. 23, 2023 , the content of which is incorporated herein by reference.

FIELD

The present disclosure relates to the field of cooling towers, in particular to a plume-abatement packing unit. On that basis, the present disclosure further relates to a plume-abatement cooling tower comprising the plume-abatement packing unit.

BACKGROUND

In petroleum, chemical and other industries, circulating water cooling systems are widely built. An existing open-type cooling tower utilizes a water-sprayed packing material to cool the circulating water. Circulating hot water from a process unit is introduced into a cooling tower spraying system, and forms sprayed circulating hot water through a water spraying head; the sprayed circulating hot water enters the water-sprayed packing material from top to bottom, and the packing material is usually made of PVC sheets; the water entering the packing material forms water films along the PVC sheets, and external dry cold air enters the packing material from bottom to top, and exchanges heat with the water films; the water films are evaporated for cooling, and the air is heated and humidified to form wet hot air; fans are mounted at the top of the cooling tower to discharge the wet hot air out of the tower; thus, the circulating hot water is cooled and becomes circulating cold water. The wet hot air flowing out of the upper part of the water-sprayed packing material is discharged out of the tower through an air duct of the cooling tower. Owing to the fact that the wet hot air discharged out of the tower has high humidity and high temperature, the wet hot air discharged out of the tower is mixed with the cold air and the mixture forms plumes containing clusters of tiny liquid droplets when the ambient temperature is low.
The water contained in the plumes containing clusters of tiny liquid droplets is the water evaporated from the water-sprayed packing material of the cooling tower, and the water contains little or no salt. Besides, chemical plants, iron and steel plants and other enterprises equipped with a large number of cooling towers are generally equipped with desalted water production devices, which utilize special technical means for removing the salt in industrial water at high cost and high energy consumption to produce desalted water. The cooling of the circulating water by the cooling tower depends on the evaporation of the circulating water on the water-sprayed packing material, the steam gas evaporated on the upper part of the water-sprayed packing material is free of salt, the plume abatement unit of an ordinary plume-abatement cooling tower recovers some of the gas evaporated on the water-sprayed packing material, and the sprayed droplets that contain salt and carried by wet hot air are also collected and mixed, and then returned to the tower. The waste of low-salt or salt-free evaporated water in the cooling tower is in sharp contrast with the high production cost and high energy consumption of desalted water in a plant.
Typically, an existing plume-abatement environmental protection device may comprise a tower body, wherein a packing material, a water spraying device, a water collector and a heat exchange device are sequentially arranged in the tower body from bottom to top, an air outlet is arranged at the top of the tower body, a fan is installed in the air outlet, and a transition section air chamber is arranged in the tower body between the heat exchange device and the air outlet. During the operation, the hot circulating cooling water sprayed by the water spraying device is cooled in the packing material by the cold air introduced from the air inlet at the bottom of the cooling tower, thereby the temperature of the circulating cooling water drops; the temperature of the cold air in the packing material rises, and the moisture content in the cold air increases, thereby wet hot air in an essentially saturated state is formed; the wet hot air enters a hot air channel after passing through the water collector, and then enters the heat exchange device to exchange heat with the dry cold air introduced into the heat exchange device through a cold air channel; after passing through the heat exchange device, the wet hot air is mixed with the dry cold air in the transition section air chamber, and then the air is exhausted to the atmosphere by the fan.
The above-mentioned prior art mainly has the following drawbacks: 1. The heat exchange device in the plume-abatement environmental protection device is the main plume abatement facility, and is equipped with a rhombic plume-abatement packing material assembly, in which the cold air and the hot air run at a high speed equal to 1.414 times the average air speed on the cross section of the cooling tower, and have high running resistance; thus, the overall performance of the cooling tower is affected. 2. The heat exchange device in the plume-abatement environmental protection device has limited heat exchange area, a low heat exchange efficiency and a poor water collection effect under a specific pressure drop requirement. 3. In the plume-abatement heat exchange device, the bottom of the plume-abatement packing material assembly is supported in a triangular form, which has low strength; in addition, air channeling between cold air and hot air exists at the two sides, and the heat exchange device may be installed in a fully encapsulated form, therefore the encapsulation and installation costs are high. 4. In the plume-abatement heat exchange device, the plume-abatement packing material assembly is composed of heat exchange sheets which are of thin film structures, and the plume-abatement packing material assembly is large in size and has low structural strength, and it is difficult to install large-size plume-abatement packing material. 5. An air damper is arranged above the water collector of the plume-abatement environmental protection device, and clearance equal to at least one time the radius of rotation of the air damper is reserved between the air damper and the water collector; consequently, the inverted tower body has high height and a high cost. 6. The condensed water that contains little salt can't be distinguished and recovered effectively.
In another plume-abatement device and a cooling tower provided in the prior art, the plume-abatement device comprises: a first flow path and a second flow path that are stacked for heat exchange between a first airflow and a second airflow that flow from bottom to top; a first outflow port for discharging the first airflow flowing out of the first flow path to a position above the plume-abatement device; and a second outflow port for discharging the second airflow flowing out of the second flow path to a position above the plume-abatement device; the first outflow port and the second outflow port are stacked alternatively, and the plume-abatement device can achieve an effect of water saving and plume abatement. The cooling tower comprises the plume-abatement device described above.
The above-mentioned prior art mainly has the following drawbacks: 1. A water collector is required for the plume-abatement tower when the plume-abatement tower is in use, consequently the cost of the plume-abatement tower is increased. 2. The sprayed droplets carried by the wet hot air are mixed with the condensed water recovered by the plume-abatement device, there is no separation between them, and the salt-free (or low-salt) condensed water is not recovered separately. 3. The bottom of the packing material has a two-section structure, the condensed water recovered by the plume-abatement device flows back to the tower through the air inlet of the plume-abatement device under gravity, and the air inlet also serves as a water discharge port; therefore, a counterflow condition is created, and air and liquid entrainment may occur easily in the process, the condensed water recovered by the plume-abatement device may be re-entrained into the plume-abatement device or left from the plume-abatement device, resulting in a compromised plume abatement effect.

SUMMARY

In order to solve the problem that the condensed water recovered by the plume-abatement packing unit may be easily entrained into the plume abatement unit or left the plume abatement unit and results in a compromised plume abatement effect in the prior art, the present disclosure provides a plume-abatement packing unit, which can effectively improve the plume abatement effect.
In order to achieve the above object, in a first aspect, the present disclosure provides a plume-abatement packing unit, which comprises a plurality of heat exchange sheets that are stacked, wherein side edges of adjacent heat exchange sheets are hermetically connected with each other to form dry cold airflow channels and wet hot airflow channels which are alternately distributed along a stacking direction and capable of realizing inter-wall heat exchange by means of the heat exchange sheets. The lower part of each heat exchange sheet is formed as an inverted trapezoidal structure, and adjacent heat exchange sheets are alternately sealed and connected at inclined edges on two sides of the inverted trapezoidal structure, so that dry cold airflow inlets in communication with the dry cold airflow channels and wet hot airflow inlets in communication with the wet hot airflow channels are alternatively formed on two opposite sides, and liquid collection outlets in communication with the wet hot airflow channels are formed at bottom short edges. Water collection and guide structures capable of guiding at least part of the water carried in an airflow introduced from the wet hot airflow inlets and/or generated by condensation of the airflow to the liquid collection outlets are formed on the sides of the heat exchange sheets facing the wet hot airflow channels. The bottom short edges of the inverted trapezoidal structures of the heat exchange sheets may be horizontal.
Preferably, the water collection and guide structure comprises guide protrusions protruding from the heat exchange sheets into the wet hot airflow channels, and each guide protrusion comprises an oblique guide protrusion that extends obliquely upward and intermittently in the inverted trapezoidal structure in the direction of the airflow from the wet hot airflow inlets to the wet hot airflow channels; condensed water generated by the condensation of the airflow introduced from the wet hot airflow inlets can be guided by the oblique guide protrusions and fall to the liquid collection outlets through gaps between adjacent oblique guide protrusions. The protrusion height of the guide protrusion may be one quarter to three quarters of the thickness of the wet hot airflow channel, preferably half of the thickness of the wet hot airflow channel.
Preferably, the water collection and guide structure further comprises a vertical guide protrusion that extends vertically upward from a top end of the oblique guide protrusion, and the guide protrusion abuts against another adjacent heat exchange sheet in the wet hot airflow channel.
Optionally, the water collection and guide structure comprises a parallel folded sheet structure formed on a main body part of the heat exchange sheet above the inverted trapezoidal structure, and adjacent heat exchange sheets are formed with upper folded sheet areas extending in parallel with each other at the main body part, so that the airflow introduced from the wet hot airflow inlets is deflected repeatedly when it flows through the upper folded sheet areas.
Preferably, the water collection and guide structure comprises a water baffle and collection structure that is formed at a position on the heat exchange sheets near the wet hot airflow inlets and extends in a direction parallel to the inclined edge of the inverted trapezoidal structure on the side of the wet hot airflow inlets, and the water baffle and collection structure is formed in a way that the flow direction of the airflow introduced from the wet hot airflow inlets is changed in the wet hot airflow channels, and the spray water carried in the airflow is directed to the liquid collection outlets. The height of the water baffle and collection structure may be approximately equal to or greater than the thickness of the wet hot airflow channel, preferably is 0.7-2 times the thickness of the wet hot airflow channel, more preferably is 0.9-1.1 times the thickness of the wet hot airflow channel. Preferably, the plume-abatement packing unit further comprises a water collection channel that is arranged at the lower side of the heat exchange sheets and opposite to the bottom short edges of the inverted trapezoidal structures. The water collection channel may have a condensed water accumulation and collection area for collecting the condensed water generated by the condensation of the airflow introduced from the wet hot airflow inlets and a spray droplet accumulation and collection area for collecting the spray water carried in the airflow introduced through the wet hot airflow inlets, and the spray droplet accumulation and collection area is spaced apart from the condensed water accumulation and collection area.
Preferably, adjacent heat exchange sheets form liquid seal ports that are in communication with the dry cold airflow channels at the bottom short edges and alternatively distributed with the liquid collection outlets in the stacking direction of the heat exchange sheets, and water collection and guide structures that are the same as those in the wet hot airflow channels are formed on the sides of the heat exchange sheets facing the dry cold airflow channels, and the water collection and guide structures are arranged in a way that at least part of the water carried in the airflow introduced from the dry cold airflow inlets and/or generated by the condensation of the airflow is guided to the liquid seal ports. The water baffle and collection structure is arranged along the wet hot airflow inlet and is obliquely directed downwards to the liquid collection outlets of the heat exchange sheets that are arranged at intervals, or the water baffle and collection structure is arranged along the wet hot airflow inlet and the dry cold airflow inlet and is obliquely directed downwards the liquid collection outlets and the liquid seal ports of the heat exchange sheets that are arranged at intervals. That is to say, the water baffle and collection structure is arranged in the wet hot airflow channel for guiding and collecting condensed water, while the dry cold airflow channel may be provided with or without the water baffle and collection structure since it doesn't produce condensed water essentially. During the operation, the water level in the water collection channel is higher than the bottom short edges of the inverted trapezoidal structures, thus isolation between hot air flow and cold air flow is realized.
In the above preferred scheme, all the liquid collection outlets and the liquid seal ports are open structures, which is to say, the liquid collection outlets connected with the hot channel and the liquid seal ports connected with the cold channel may be opened within the range of the entire length of the bottom short edges of the inverted trapezoidal structures to form fully open structures or semi-open structures.
Preferably, the top edges of the heat exchange sheets are formed as horizontal straight edges or downwardly recessed multi-segment edges, and adjacent heat exchange sheets form cold channel outlets that are alternately distributed in the stacking direction and in communication with the dry cold airflow channels and hot channel outlets that are in communication with the wet hot airflow channels across the length of the top edges.
Preferably, the top edges of the heat exchange sheets extend along a wavy line respectively, and adjacent heat exchange sheets are connected with each other at peaks/valleys, so as to form cold channel outlets that are alternately distributed in the stacking direction and in communication with the dry cold airflow channels and hot channel outlets that are in communication with the wet hot airflow channels across the length of the top edges; and the cold channel outlets and the hot channel outlets form cellular top outlets.
Preferably, the heat exchange sheets are formed with columnar supports that extend in the dry cold airflow channels and/or the wet hot airflow channels and abut against adjacent heat exchange sheets.
In the present disclosure, the material of the heat exchange sheets may be selected from one of PVC, PP or similar film composite materials, preferably PVC heat-conductive plastics.
In a second aspect, the present disclosure provides a plume-abatement cooling tower, which comprises a tower body, and a plume-abatement packing layer, a spraying unit and a water-sprayed packing layer that are arranged in the tower body from top to bottom, wherein the plume-abatement packing layer comprises a plurality of plume-abatement packing units of any of claims 1 to 9, which are connected with each other on their sides; the tower body is formed with a cooling tower air inlet located at a lower side of the water-sprayed packing layer and a plurality of dry cold air channels that are located between the plume-abatement packing layer and the spraying unit and in communication with the dry cold airflow inlets respectively; and wet hot air channels that enable a spray liquid evaporated by the water-sprayed packing layer to flow to the wet hot airflow inlets are provided between adjacent dry cold air channels.
With the above technical scheme, at least part of the water carried in the airflow introduced from the wet hot airflow inlet and/or generated by the condensation of the airflow can be guided to the liquid collection outlets formed at the bottom short edges of the inverted trapezoidal structures of corresponding heat exchange sheets by the water collection and guide structure, thereby preventing the condensed water recovered in the plume-abatement packing unit from being carried into the plume-abatement unit through counterflow against the wet hot airflow at the wet hot airflow inlet, which is to say, the wet hot airflow to be treated and the condensed water are introduced into and discharged from the plume-abatement packing unit through different parts of the plume-abatement packing unit (the inclined edges and bottom short edges of the inverted trapezoidal structures) respectively; thus, the plume abatement effect is improved significantly.
In addition, compared with the prior art, the plume-abatement packing unit and the plume-abatement cooling tower in preferred embodiments of the present disclosure have the following beneficial effects:

1. The plume-abatement packing unit in the present disclosure may be provided with water baffle and collection structures on the two sides of the inverted trapezoidal structures at the lower part of the heat exchange sheets; thus, on one hand, the overall structural strength of the plume-abatement packing material can be greatly improved; on the other hand, when the wet hot air passes through the water baffle and collection protrusion structure, the tiny water droplets carried by the wet hot air strike the outer side of the water baffle and collection structure, and the tiny water droplets are captured by baffling under the action of inertia force, and collected under the action of gravity; especially, the tiny water droplets and the condensed water can be recovered separately, thus the value of utilization of the low-salt condensed water is improved. The plume-abatement packing unit in the present disclosure has a better water collection and plume-abatement function, and the water collector layer used in an existing cooling tower can be canceled in a water collection and plume-abatement tower that contains the plume-abatement packing unit disclosed in the present disclosure. Besides, a vertical guide channel is provided in the plume-abatement packing unit in the present disclosure, and can be used to capture the water droplets carried in the wet hot air by means of the difference in inertia in the inverted structure owing to the difference in density between gas and liquid, and the captured water droplets can be guided through the oblique guide channel to the water collection channel at the lower part, so as to reduce the water droplets carried in the wet hot airflow and enhance the water collection and plume-abatement ability.
With the unique two-stage serial entrained droplet capturing structure, 95% or more entrained liquid can be removed, and the removal ratio of entrained droplets in diameter greater than or equal to 20µm can be approximately 100%.
2. The plume-abatement packing unit in the present disclosure can be open at the bottom short edges of the inverted trapezoidal structures at the lower part of the heat exchange sheets, the bottom short edges are horizontal and configured into open or semi-open structures, so as to separate the air inlet from the liquid discharge port, reduce the entrainment caused by gas-liquid counterflow, and enhance the effect of separation between the salt-containing water and the low-salt water and improve the recovery efficiency of the low-salt water. The open or semi-open structures abut against the water collection channel in the regions, thereby the weight of the entire water collection and plume-abatement packing material can be supported well to prevent deformation; the bottom short edges of the inverted trapezoidal structures at the lower part of the heat exchange sheets are open structures, forming liquid collection outlets and liquid seal ports; the water baffle and collection structure, the vertical guide channel and the oblique guide channel arranged in the water collection and plume-abatement packing unit can recover the salt-containing spray droplets carried in the wet hot air and the salt-free condensed water separated from the hot wet air in different regions respectively, and guide them to the spray droplet accumulation and collection area and the condensed water accumulation and collection area in the water collection channel in the regions.
With the unique structure that separates the air inlet and the liquid discharge port and the regional water collection mechanism, the salt content in the entrained spray water recovered by the water collector in the region is different from the salt content in the recovered condensed water by about 100 times; the salt content in the desalted water is 1-15 ppm, which essentially meets the requirement for low-grade desalted water. Thus, the plume-abatement device also has a function of producing high-value desalted water, the economic value of the plume-abatement device is greatly improved, the desalted water production device in the enterprise can be canceled or the scale of the desalted water production device can be reduced, and the overall economic benefit of the enterprise can be improved.
3. In the water collection and plume-abatement cooling tower in the present disclosure, owing to the fact that the plume-abatement packing material has a remarkable water collection function, the water collector used in an existing cooling tower can be canceled, the air damper has a sufficient rotation space, the overall height of the tower can be reduced by 1-2 meters compared with a tower in the prior art, and the equipment cost can be reduced greatly.
4. The water collection and plume-abatement packing material in the present disclosure and the heat exchange sheets are polygonal, the upper part of the two vertical edges of each heat exchange sheet forms a three-segment top polyline structure that is recessed downwards in the middle; thus, the structure corresponds well to the inverted trapezoidal structure at the lower part of the heat exchange sheet. When the heat exchange sheets are produced from the water collection packing material by edge folding, the bottom structure of each heat exchange sheet conforms to the top structure of the heat exchange sheet in shape, thereby the waste material can be greatly reduced, and the ratio of waste material can be approximately zero, thus, the cost is reduced.
5. In the water collection and plume-abatement cooling tower in the present disclosure, the wet hot air and the cold air are introduced into the plume-abatement packing unit through the air inlets on the two sides of the inverted trapezoidal structures at the lower part of the plume-abatement packing material respectively. When the air is introduced into the plume-abatement packing material initially, the actual inlet area on each side of the inverted trapezoidal structures at the lower part of the plume-abatement packing unit is reduced by half because the hot channel and the cold channel are spaced apart from each other, and the initial flow rate of the air introduced into the packing material is equivalent to 1.4 times the air flow rate on the cross section of the tower; when the air enters the upper part of the inverted trapezoidal structure of the plume-abatement packing material through the cold channel and the hot channel, the air flow rate is reduced to be equal to the air flow rate on the cross section of the tower, and the pressure drop across the plume-abatement packing unit and the plume-abatement packing layer is only about 50% of the pressure drop in the prior art.
6. In the water collection and plume-abatement cooling tower in the present disclosure, after the air is introduced into the plume-abatement packing material, the air leaves from the top outlets of the heat exchange sheets finally. Since the hot channel and the cold channel at the top polyline outlets are arranged at intervals, the air can be uniform mixed quickly after it leaves the plume-abatement packing material from the hot channel and the cold channel at the two outlets, no additional mixing space is required at the top part of the water collection and plume-abatement tower, thereby the height of the tower body can be further reduced.
7. In the water collection and plume-abatement cooling tower in the present disclosure, the plume-abatement packing layer is formed by a plurality of plume-abatement packing units with sides abutting against each other. The installation cost of the plume-abatement packing layer is low, and the manufacturing cost of the entire tower is low.
8. A rotary baffle of the air damper is arranged in the plume-abatement channel; in summer, the rotary baffle of the air damper is in a vertical position and the louver is closed, and the wet hot air is discharged out of the cooling tower through the cold channel and the hot channel of the plume-abatement packing material at the same time; in winter, the rotary baffle of the air damper is in a horizontal position, the louver is opened, the dry cold air enters the cold channel of the plume-abatement packing material through the cold air channel, while the wet hot air enters the hot channel of the plume-abatement packing material through the wet hot air channel. The plume-abatement cooling tower in the present disclosure includes two operation modes, i.e., a water collection and plume-abatement operation mode and a thermal operation mode, which are suitable for different seasons. Therefore, the plume-abatement cooling tower has flexibility in operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the plume-abatement packing unit according to a first embodiment of the present disclosure;
Fig. 2 is a schematic diagram of the assembled structure of the plume-abatement packing unit according to the first embodiment of the present disclosure;
Fig. 3 is a schematic structural diagram of the sealing edge structures on the two sides of the inverted trapezoidal structure of the heat exchange sheet;
Fig. 4 is a schematic structural diagram of the structure at the bottom short edge of the inverted trapezoidal structure of the heat exchange sheet;
Fig. 5a is a schematic structural diagram of installation of the water collection channel;
Fig. 5b is a schematic diagram of the joint of the water collection channel;
Fig. 6 is a schematic structural diagram of the vertical guide protrusion;
Fig. 7 is a schematic structural diagram of the oblique guide protrusion;
Fig. 8 is a schematic diagram of the plume-abatement cooling tower in a second embodiment of the present disclosure in a plume-abatement operation mode;
Fig. 9 is a schematic diagram of the plume-abatement cooling tower in a non-plume-abatement operation mode;
Fig. 10 is a schematic diagram of the plume-abatement cooling tower according to a third embodiment of the present disclosure;
Fig. 11 is an isometric view of the plume-abatement packing unit used in the plume-abatement cooling tower in Fig. 10;
Fig. 12 is a schematic diagram of the water collection channel at the bottom of the plume-abatement packing unit used in the plume-abatement cooling tower in Fig. 10;
Fig. 13 is a schematic diagram of the plume-abatement packing unit according to a fourth embodiment of the present disclosure;
Fig. 14 is a schematic diagram of the plume-abatement packing unit according to a fifth embodiment of the present disclosure;
Fig. 15 is a partially enlarged view of the plume-abatement packing unit in Fig. 14;
Fig. 16 is a partially enlarged view of the plume-abatement packing unit in Fig. 14;
Fig. 17 is a schematic diagram of the plume-abatement packing unit according to a sixth embodiment of the present disclosure;
Fig. 18 is a partially enlarged view of the plume-abatement packing unit in Fig. 17;
Fig. 19 is a partially enlarged view of the plume-abatement packing unit in Fig. 17.

Reference Numerals

1001 - heat exchange sheet; 1002 - vertical guide protrusion; 1003 - water baffle and collection structure; 1004 - oblique guide protrusion; 1005 - water collection channel; 1006 - top polyline; 1007 - included angle of top polyline; 1008 - inclined sealing edge surface; 1009 - inclined edge-sealing surface; 1010 - included angle of sealing surface; 1011 - bottom short edge; 1012 - inclined edge; 1013 - wet hot air; 1014 - dry cold air; 1015 - spray droplet collection and discharge outlet; 1016 - condensed water collection and discharge outlet; 1017 - condensed water accumulation and collection area; 1018 - spray droplet accumulation and collection area; 1019 - cold channel outlet; 1020 - hot channel outlet; 1021 - vertical sealing edge surface; 1022 - wet hot airflow inlet; 1023 - liquid collection outlet; 1024 - liquid seal port; 1025 - dry cold airflow inlet; 1026 - inverted trapezoidal structure; 1027 - plume-abatement packing unit; 1028 - side edge; 1029 - condensed water droplet; 1030 - gap; 1031 - windward side of water baffle and collection structure;
2001 - air inlet of cooling tower; 2002 - water-sprayed packing layer; 2003 - spraying unit; 2004 - air damper; 2005 - dry cold air channel; 2006 - wet hot air channel; 2007 - air duct; 2008 - air outlet of cooling tower; 2009 - louver; 2010 - partition; 2011 - tower body; 2012 - blower fan; 2013 - plume-abatement packing layer;
3001 - plume-abatement packing unit; 3002 - top outlet; 3003 - water collection channel;
4001 - plume-abatement packing unit; 4002 - top outlet;
5001 - wet hot airflow inlet; 5002 - liquid collection outlet; 5003 - liquid seal port; 5004 - support strengthening area; 5005 - dry cold airflow inlet; 5006 - plume-abatement packing unit; 5007 - inverted trapezoidal structure; 5008 - upper folded sheet area; 5009 - columnar support;
6001 - heat exchange sheet; 6002 - liquid collection outlet; 6003 - liquid seal port; 6004 - vertical guide protrusion; 6005 - upper spoiler; 6006 - plume-abatement packing unit; 6007 - inverted trapezoidal structure; 6008 - oblique guide protrusion; 6009 - spoiler of inverted trapezoidal structure; 6010 - water baffle and collection structure.

DETAILED DESCRIPTION

Specific embodiments of the present disclosure will be detailed below with reference to the accompanying drawings. It may be understood that the embodiments described herein are only provided to describe and explain the present disclosure, but are not intended to constitute any limitation on the present disclosure.
In the present disclosure, unless otherwise specified, the terms that denote the orientations are used as follows, for example, "top", "bottom", "left" and "right" usually refer to "top", "bottom", "left" and "right" as shown in the accompanying drawings; "inside" and "outside" refer to inside and outside in relation to the outlines of the components.
Figs. 1 to 19 provide a plume-abatement packing unit in different embodiments. The plume-abatement packing unit comprises a plurality of heat exchange sheets arranged in a stacked manner, with side edges of adjacent heat exchange sheets hermetically connected with each other to form dry cold airflow channels and wet hot airflow channels that are alternately distributed in the stacking direction and can exchange heat through the walls of the heat exchange sheets. The lower part of each heat exchange sheet is formed into an inverted trapezoidal structure, and adjacent heat exchange sheets are alternately sealed and connected at inclined edges on two sides of the inverted trapezoidal structure, so that dry cold airflow inlets in communication with the dry cold airflow channels and wet hot airflow inlets in communication with the wet hot airflow channels are alternatively formed on two opposite sides, and liquid collection outlets in communication with the wet hot airflow channels are formed at bottom short edges, and water collection and guide structures capable of guiding at least part of the water carried in an airflow introduced from the wet hot airflow inlets and/or generated by condensation of the airflow to the liquid collection outlet to the liquid collection outlets are formed on the sides of the heat exchange sheets facing the wet hot airflow channels.
At least part of the water carried in the airflow introduced from the wet hot airflow inlet and/or generated by the condensation of the airflow can be guided to the liquid collection outlets formed at the bottom short edges of the inverted trapezoidal structures of corresponding heat exchange sheets by the water collection and guide structure, thereby preventing the condensed water recovered in the plume-abatement packing unit from being carried into the plume-abatement unit through counterflow against the wet hot airflow at the wet hot airflow inlet, which is to say, the wet hot airflow to be treated and the condensed water are introduced into and discharged from the plume-abatement packing unit through different parts of the plume-abatement packing unit (the inclined edges and bottom short edges of the inverted trapezoidal structures) respectively; thus, the plume abatement effect is improved significantly.
As described later in different embodiments, the water collection and guide structure may comprise guide protrusions and/or water baffle and collection structures. The guide protrusions can guide the salt-free condensed water separated from the wet hot air flow to liquid collection outlets, and the water baffle and collection structures can guide the salt-containing spray droplets carried in the wet hot air to liquid collection outlets. Corresponding guide protrusions formed on adjacent heat exchange sheets face each other or abut against each other in the wet hot airflow channel to separate the wet hot airflow channel into a plurality of through-flow areas; to that end, the height of the guide protrusion on each heat exchange sheet may be half of the thickness of the wet hot airflow channel. Alternatively, the protrusion height of the guide protrusion may be equal to the thickness of the wet hot airflow channel, so that it can abut against another adjacent heat exchange sheet.
It may be understood that although the lower part of the heat exchange sheet is described as an "inverted trapezoidal structure", the lower part of the heat exchange sheet is not limited to a strict trapezoidal shape, for example, its "bottom short edge" may extend in the horizontal direction, or have a proper inclination angle with respect to the horizontal direction or extend along a wavy line based on the horizontal direction. Similarly, the inclined edge of the inverted trapezoidal structure may be in other shapes than a straight shape. Therefore, the term "inverted trapezoidal structure" used in the present disclosure is only for the convenience of clarity and conciseness of expression, and the structure is within the scope of the concept of the present disclosure as long as the lower parts of the heat exchange sheets are hermetically connected to form liquid collection outlets, and dry cold airflow inlets and wet hot air channels on the two sides, and the side of the heat exchange sheets facing the wet hot airflow channels is formed with a water collection and guide structure capable of guiding at least part of the water carried in the airflow introduced from the wet hot airflow inlet and/or condensed from the airflow to the liquid collection outlets. The term "inverted" mainly means that the length of the bottom short edge of the trapezoidal structure at the lower part of the heat exchange sheet is smaller than the length of the trapezoidal structure at a position where the trapezoidal structure meets the main body of the heat exchange sheet at the upper part. For example, typically, as shown in Fig. 1, the inverted trapezoidal structure of the heat exchange sheet can be an isosceles trapezoid including a top long edge and a bottom short edge 1011, and inclined edges 1012 on the two sides are equal to each other in length.
The plume-abatement packing unit may further comprise a water collection channel arranged at the lower side of the heat exchange sheets and opposite to the bottom short edge of the inverted trapezoidal structure, and the water collection channel has a condensed water accumulation and collection area for collecting condensed water and a spray droplet accumulation and collection area for collecting spray water. Thus, the salt-free condensed water separated from the wet hot airflow and the salt-containing spray droplets carried by the wet hot airflow are guided to different areas of the water collection channel, so as to realize zoned recovery, and meet the requirement for low-grade desalted water, thereby the plume-abatement device has the function of producing high-value desalted water at the same time, the economic value of the plume-abatement device is greatly improved, the desalted water production device in the enterprise can be canceled, or the scale of the desalted water production device can be reduced, and the overall economic benefit of the enterprise can be improved.
In order to save the production cost, the heat exchange sheets may have the same structure. Thus, after the plume-abatement packing unit is assembled and formed, a water collection and guide structure is also formed on the side of the heat exchange sheets facing the dry cold airflow channel, and the water collection and guide structure is the same as the water collection and guide structure in the wet hot airflow channel. Correspondingly, a liquid seal port in communication with the dry cold airflow channel is further formed at a position corresponding to the bottom short edge of the inverted trapezoidal structure, and at least part of the water carried in the airflow introduced into the dry cold airflow channel from the dry cold airflow inlet and/or generated by the condensation of the airflow can be guided to the liquid seal port. However, the water baffle and collection structure may be provided or canceled, since essentially no condensed water is produced in the dry cold airflow channel in a normal water collection and plume-abatement mode.
Different embodiments of the present disclosure will be described below with reference to the accompanying drawings. It may be understood that these embodiments are only illustrative, and the technical features in different embodiments can be interchanged to form more other embodiments within the scope of the present disclosure, without violating the technical principle of the present disclosure.

Embodiment 1:

In this embodiment, a preferred structure of the water collection and plume-abatement unit is provided.
As shown in Figs. 1- 7, the plume-abatement packing unit 1027 in the present disclosure is composed of a plurality of heat exchange sheets 1001 that are vertically arranged and stacked (or laminated); the two sides of the heat exchange sheet 1001 have vertically extending side edges 1028, and the lower part connected with the side edges is an inverted trapezoidal structure 1026; the opposite side edge 1028 of the heat exchange sheet 1001 is provided with a vertical sealing edge surface 1021, forming a wet hot airflow channel and a dry cold airflow channel that are opposite to and spaced apart from each other; the opposite sides of the inverted trapezoidal structures 1026 of adjacent heat exchange sheets 1001 are alternatively surrounded by inclined sealing edge surfaces 1008, forming a wet hot airflow inlet 1022 and a dry cold airflow inlet 1025 that are arranged at an interval.
The wet hot airflow inlet 1022 and the dry cold airflow inlet 1025 (i.e., openings formed by the opposite sides of the inverted trapezoidal structure 1026 at the lower part of adjacent heat exchange sheets 1001 that alternately surrounded by the inclined sealing edge surfaces 1008) are arranged at an interval, and the other side of the inverted trapezoidal structure 1026 opposite to the wet hot airflow inlet 1022 and the dry cold airflow inlet 1025 is closed by the inclined sealing edge surfaces 1008. There is no air channeling between the wet hot airflow channel and the dry cold airflow channel that are opposite to and spaced apart from each other.
The bottom short edges 1011 of the inverted trapezoidal structures 1026 of adjacent heat exchange sheets 1001 form a downward opening structure, and adjacent opening structures are respectively connected to the wet hot airflow channel and the dry cold airflow channel, forming liquid collection outlets 1023 and liquid seal ports 1024 that are arranged at an interval.
As shown in Figs. 1 and 2, the lower part of the heat exchange sheet 1001 is an inverted trapezoidal structure 1026, which has a short bottom edge 1011 and inclined edges 1012 on two sides, and the top of the heat exchange sheet 1001 is a top polyline 1006, and the top polylines 1006 of adjacent heat exchange sheets 1001 form cold channel outlets 1019 and hot channel outlets 1020. Water baffle and collection structures 1003 are respectively arranged in the wet hot airflow channel near the inclined edge 1012 of the inverted trapezoidal structure and in the dry cold airflow channel near the inclined edge 1012 of the inverted trapezoidal structure, and guide protrusions are arranged in the heat exchange sheets 1001. The upper part of the inverted trapezoidal structure 1026 of the heat exchange sheet 1001 is provided with vertical guide protrusions 1002 extending in the vertical direction, and the convex or concave shapes of adjacent vertical guide protrusions 1002 on the heat exchange sheet 1001 are opposite in direction. The inverted trapezoidal part 1026 of the heat exchange sheet is provided with inclined and intermittent oblique guide protrusions 1004, which extend obliquely upward and intermittently in the inverted trapezoidal structure 1026 in the direction in which the airflow is introduced from the wet hot air inlet 1022 or the dry cold airflow inlet 1025 to the wet hot air channel or the dry cold air channel, and the convex or concave shapes of the oblique guide protrusions in different directions of inclination.
As shown in Figs. 2 and 4, wet hot air 1013 is introduced into the wet hot airflow channel from the wet hot airflow inlet 1022, and dry cold air 1014 is introduced into the dry cold airflow channel from the dry cold airflow inlet 1025; the air flowing out of the wet hot airflow channel leaves the plume-abatement packing unit through the hot channel outlet 1020; the air flowing out of the dry cold airflow channel leaves the plume-abatement packing unit through the cold channel outlet 1019; the air flowing out of the hot channel outlet 1020 and the air flowing out of the cold channel outlet 1019 are mixed in the upper part of the plume-abatement packing unit, and the mixture is further discharged out of the cooling tower.
As shown in Fig. 3, the inclined sealing edge surface 1008 is perpendicular to the base surface of the heat exchange sheet 1001, forming an included angle 1010 of the sealing surface. The side of the inclined sealing edge surface 1008 that is not connected with the heat exchange sheet 1001 extends out of the inclined edge-sealing surface 1009, which is perpendicular to the inclined sealing edge surface 1008. The heat exchange sheets 1001 may be bent in the same direction near the wet hot airflow inlet 1022 to form a water baffle and collection structure 1003, and the bending height may be approximately equal to or greater than the thickness of the wet hot airflow channel, preferably 0.7-2 times the thickness of the wet hot airflow channel, more preferably 0.9-1.1 times the thickness of the wet hot airflow channel. Besides, the water baffle and collection structure 1003 extends in a direction parallel to the inclined edge 1012 of the inverted trapezoidal structure 1026 at the side of the wet hot airflow inlet 1022. Thus, the water baffle and collection structure 1003 can change the flow direction of the airflow introduced from the wet hot airflow inlet 1022 in the wet hot airflow channel, and the spray droplets carried in the airflow hit the windward side 1031 of the water baffle and collection structure and are captured. Then, under the action of gravity, these spray droplets are guided to the liquid collection outlets in the extension direction of the water baffle and collection structure 1003.
As shown in Figs. 5a and 5b, the water collection channel 1005 closely abuts against the bottom short edge 1011 of the inverted trapezoidal structure at the lower part of the heat exchange sheet 1001; the two sides of the water collection channel 1005 are spray droplet accumulation and collection areas 1018, and the middle part of the water collection channel 1005 is a condensed water accumulation and collection area 1017. A spray droplet accumulation and discharge outlet 1015 is in communication with the spray droplet accumulation and collection area 1018, and a condensed water accumulation and discharge outlet 1016 is in communication with the condensed water accumulation and collection area 1017.
As shown in Figs. 6 and 7, the wet hot air 1013 entering the wet hot airflow channel of the plume-abatement packing unit 1027 and the dry cold air 1014 entering the dry cold airflow channel from the dry cold airflow inlet 1025 exchange heat through the heat exchange sheets 1001, and the wet hot air is condensed. Owing to the heat exchange with the dry cold air, the temperature of the wet hot air 1013 drops, condensed water precipitates from the saturated wet hot air 1013 as the temperature drops, and the condensed water adheres to the heat exchange sheets and is carried by the wet hot air. The wet hot air 1013 carrying the condensed water is guided by the oblique guide protrusions 1004 into the upper part of the inverted trapezoidal structure 1026, and changes its flow direction in the process. Owing to the inertia difference resulted from the density difference, the condensed water carried by the wet hot air 1013 hits the vertical guide protrusions 1002 due to inertia, and the condensed water droplets 1029 carried in the wet hot air are captured by the vertical guide protrusions 1002.
Under the action of gravity, the condensed water droplets adhering to and captured by the heat exchange sheets in the wet hot airflow channel flow along the vertical guide protrusions 1002 and the oblique guide protrusions 1004, and flow to the lower part through the gaps 1030 between the oblique guide protrusions, and further enter the condensed water accumulation and collection area 1017 of the water collection channel 1005.
A part of the wet hot air 1013 carrying spray droplets from the water-sprayed packing material directly enters the plume-abatement packing unit 1027 through the wet hot airflow inlet 1022. The remaining part of the wet hot air 1013 flows to the inclined sealing edge surface 1008, is baffled by the inclined sealing edge surface 1008, and then enters the plume-abatement packing unit 1027 through the hot channel air inlet 1022. The spray droplets carried in the wet hot air 1013 baffled by the inclined sealing edge surface 1008 are blocked and captured by the inclined sealing edge surface 1008, and flow to the spray droplet accumulation and collection area 1018 of the water collection channel 1005 along the inclined edge-sealing surface 1009.
After entering the plume-abatement packing unit 1027, the wet hot air 1013 carrying spray droplets passes through the water baffle and collection structure 1003 first, and the wet hot air 1013 carrying spray droplets is baffled by the water baffle and collection structure 1003. In the wet hot air baffling process, owing to the fact that the density of the spray droplets carried in the wet hot air is much higher than that of the wet hot air, the spray droplets have higher inertia; the spray droplets hit the windward side 1031 of the water baffle and collection structure, the spray droplets carried in the wet hot air are captured and removed by the water baffle and collection structure, and flow into the spray droplet accumulation and collection area 1018 of the water collection channel 1005 along the windward side 1031 of the water baffle and collection structure under the action of gravity.
The liquid seal port 1024 is sealed by the liquid in the water collection channel 1005 to prevent air channeling between the cold air and the hot air.
In this embodiment, as shown in Fig. 1, the top edge of the heat exchange sheet 1001 is formed as a multi-segment edge that is recessed downward, i.e., a top polyline 1006, which includes three segments that generally correspond to the bottom short edge 1011 and the inclined edges 1012 of the inverted trapezoidal structure 1026, and forms an included angle 1007 of top polyline. Thus, the upper part of the two vertical edges of each heat exchange sheet forms a three-segment top polyline structure that is recessed downwards in the middle, thus, the structure corresponds well to the inverted trapezoidal structure at the lower part of the heat exchange sheet. When the heat exchange sheets are produced from the water collection packing material by edge folding, the bottom structure of each heat exchange sheet conforms to the top structure of the heat exchange sheet in shape, thereby the waste material can be greatly reduced, and the ratio of waste material can be approximately zero, thus, the cost is reduced.

Embodiment 2:

This embodiment provides a plume-abatement cooling tower structure utilizing the plume-abatement packing unit 1027 in Embodiment 1.
As shown in Figs. 8 and 9, the plume-abatement cooling tower in the present disclosure comprises a tower body 2011, the lower part of the tower body 2011 is provided with a cooling tower air inlet 2001, and the upper end of the tower body 2011 is provided with a cooling tower air outlet 2008, which is configured to guide the airflow by means of an air duct 2007, and a blower fan 2012 is arranged in the air duct 2007; a water-sprayed packing layer 2002 is provided at the upper part of the cooling tower air inlet 2001, and a spraying unit 2003 for spraying hot water is provided above the water-sprayed packing layer 2002; an air damper 2004 is provided above the spraying unit 2003, a water collection channel 1005 is provided at the upper part of the air damper 2004, a plume-abatement packing layer 2013 composed of a plurality of plume-abatement packing units 1027 is provided above the water collection channel 1005, and the sides of the plurality of plume-abatement packing units described in Embodiment 1 abut against each other to form the plume-abatement packing layer 2013.
As shown in Fig. 8, the plume-abatement channel comprises partitions 2010 and air dampers 2004. The partitions and the air dampers divide the plume-abatement channel system into a dry cold air channel 2005 and a wet hot air channel 2006. The dry cold air channel 2005 is in communication with a louver 2009 on a side of the tower body 2011. The louver 2009 is arranged on the side wall of the cooling tower, and also serves as a cold air inlet during the operation of the cooling tower in a plume-abatement mode.
There is no air channeling between the wet hot air channel 2006 and the dry cold air channel 2005. The upper ends of the partitions 2010 are connected to the bottom of the water collection channel 1005, the top surface of the water collection channel 1005 abuts against the liquid collection outlet 1023 and the liquid seal port 1024 at the lower part of the inverted trapezoidal structure of the plume-abatement packing unit 1027, the air dampers 2004 are arranged at an interval at the lower ends of adjacent partitions 2010, and the lower ends of the partitions 2010 are connected with the side edges of the air dampers 2004. A dry cold airflow channel 2005 is formed between the partitions, the air dampers and the plume-abatement packing layer 2013 (the air dampers 2004 are closed, i.e., in a horizontal position), and the wet hot air in the cooling tower can't enter the dry cold air channel 2005. In this state, air can be introduced into the dry cold air channel 2005 only through the shutter 2009 arranged on the side wall of the cooling tower.
The air damper 2004 can rotate along its central axis of rotation, and can be in a horizontal position (a plume-abatement mode) or a vertical position (a non-plume-abatement mode).
The operating process of the water-saving and plume-abatement cooling tower in the present disclosure in the plume-abatement mode is as follows:
As shown in Fig. 8, circulating hot water is uniformly sprayed on the water-sprayed packing material 2002 through the spraying unit 2003, external dry cold air 1014 is driven by the blower fan 2012 and flows into the cooling tower from the cooling tower air inlet 2002 at the lower part of the tower, flows upward through the water-sprayed packing layer 2002, and contacts with the circulating hot water sprayed downward from above the water-sprayed packing layer 2002 in a counter-current manner, and transfers heat and mass on the surface of the water-sprayed packing layer 2002, so that the circulating hot water is cooled, leaves the water-sprayed packing layer 2002, and falls into the water collection tank below the cooling tower air inlet 2001; the external dry cold air passes through the water-sprayed packing layer 2002 and is heated into saturated wet hot air 1013, the saturated wet hot air 1013 leaves the water-sprayed packing material, enters the wet hot air channel 2006, and then enters the wet hot air channel of the plume-abatement packing unit 1027 through the wet hot air channel 2006. The air dampers 2004 are closed, and the louver 2009 is opened. The partitions 2010 and the air dampers 2004 form the dry cold air channel 2005. Under a sucking effect of the blower fan 2012, the external dry cold air is introduced through the louver 2009 into the dry cold air channel 2005, and then enters the dry cold airflow channel of the plume-abatement packing unit 1027. In the plume-abatement packing unit, the captured spray droplets are accumulated, and the condensed water produced by cooling is accumulated; the spray droplets and the condensed water are discharged through the liquid collection outlets 1023 at the lower part of the plume-abatement packing unit 1027 to the spray droplet accumulation and collection area 1018 and the condensed water accumulation and collection area 1017 of the water collection channel 1005 respectively; the water baffle and collection structure 1003 attains an effect of isolating and diverting the accumulated spray droplets and the accumulated condensed water. The condensed water collected in the condensed water accumulation and collection area 1017 contains little salt, and can be directly used a low-grade desalted water; thus, the production cost of desalted water is greatly reduced.
Fig. 9 depicts the operating process of the water-saving and plume-abatement cooling tower in summer (i.e., a thermal operation mode): circulating hot water is uniformly sprayed on the water-sprayed packing layer 2002 through the spraying unit 2003, and external dry cold air is driven by the blower fan 2012 and flows into the lower part of the tower body, flows upward through the water-sprayed packing layer 2002, and contacts with the circulating hot water sprayed downward from above the water-sprayed packing layer 2002 in a counter-current manner, and transfers heat and mass on the surface of the water-sprayed packing layer 2002, so that the circulating hot water is cooled, leaves the water-sprayed packing layer 2002, and falls into the water collection tank at the lower part of the cooling tower air inlet 2001; the external dry cold air passes through the water-sprayed packing layer 2002 and is heated into saturated wet hot air, which leaves the water-sprayed packing layer 2002 and enters the plume-abatement channel. The air dampers 2004 rotate to a vertical state (open) around its axis of rotation, while the louver 2009 connected to the dry cold air channel 2005 is in a closed state; thus, the wet hot air from the water-sprayed packing layer 2002 enters the plume-abatement packing unit 1027 through the dry cold air channel 2005 and the wet hot air channel 2006 of the plume-abatement channel, and the dry cold airflow channel and the wet hot airflow channel of the plume-abatement packing unit 1027 are fully used as a wet hot air channel. The wet hot air carries a lot of liquid water droplets. The water droplets are captured by the inclined sealing edge surface 1008, the water baffle and collection structure 1003, and the vertical guide protrusions 1002 sequentially as they flow in the dry cold airflow channel and the wet hot airflow channel in the plume-abatement packing unit 1027, and are guided and accumulated; the accumulated water in the dry cold airflow channel and the wet hot airflow channel flows through the liquid collection outlet 1023 and the liquid seal port 1024 of the plume-abatement packing unit 1027 into the water collection channel 1005, and is further recovered.

Embodiment 3:

This embodiment provides a variant of the plume-abatement packing unit and a plume-abatement cooling tower.
As shown in Figs. 10 and 11, the plume-abatement cooling tower in this embodiment has essentially the same composition and operating principle as the plume-abatement cooling tower described in Embodiment 2, except that the top outlet 3002 of the plume-abatement packing unit 3001 used in this embodiment is in a horizontal state, which is to say, the top edges of the heat exchange sheets are formed as horizontal straight edges, so that cold channel outlets in communication with the dry cold airflow channel and hot channel outlets in communication with the wet hot airflow channel are alternatively distributed in the stacking direction across the length of the top edges.
In addition, as shown in Fig. 12, the bottom short edges of the heat exchange sheets in the plume-abatement packing unit 3001 abut against the water collection channel 3003, which is not partitioned. As a result, the collected spray water and condensed water are mixed.

Embodiment 4:

This embodiment provides a second variant of the plume-abatement packing unit.
As shown in Fig. 13, the top outlet 4002 of the plume-abatement packing unit 4001 is in a cellular shape. Specifically, the top edges of the heat exchange sheets of the plume-abatement packing unit 4001 extend along a wavy line respectively, and adjacent heat exchange sheets are connected with each other at peaks/valleys, so as to form cold channel outlets that are alternately distributed in the stacking direction and in communication with the dry cold airflow channels and hot channel outlets that are in communication with the wet hot airflow channels across the length of the top edges; and the cold channel outlets and the hot channel outlets form cellular top outlets 4002.

Embodiment 5:

This embodiment provides a third variant of the plume-abatement packing unit.
As shown in Figs. 14 to 16, the lower part of each heat exchange sheet used in the plume-abatement packing unit 5006 is formed into an inverted trapezoidal structure 5007, and the upper part of the heat exchange sheet is formed as an upper folded sheet area 5008; the upper folded sheet areas 5008 of adjacent heat exchange sheets are supported and separated by columnar supports 5009, forming a dry cold airflow channel and a wet hot airflow channel.
As shown in Fig. 15, wet hot air is introduced into the plume-abatement packing unit from the wet hot air inlet 5001, and the accumulated liquid produced or captured by the plume-abatement packing unit flows out of the liquid collection outlet 5002 into the water collection channel. Cold air is introduced into the plume-abatement packing material from the dry cold airflow inlet 5005, and the liquid seal port 5003 at the lower part of the plume-abatement packing material is sealed by the liquid in the water collection channel to prevent air channeling between the cold air and the hot air. In this embodiment, the bottom short edges of the inverted trapezoidal structure 5007 of adjacent heat exchange sheets are connected with each other at the part away from the corresponding wet hot air inlet 5001 or dry cold airflow inlet 5005 to form a liquid collection outlet 5002 and a liquid seal port 5003 that are in a semi-open structure respectively. The part of the heat exchange sheet near the short bottom edge may be strengthened to form a support strengthened area 5004.
As shown in Fig. 16, the upper folded sheet area 5008 is a parallel folded sheet structure, and the heat exchange sheets are supported and separated from each other by columnar supports 5009. When the wet hot air passes through the upper folded sheet area of the plume-abatement packing unit, it is repeatedly baffled by the folded sheet area, and the droplets carried in the airflow are captured.

Embodiment 6:

This embodiment provides a fourth variant of the plume-abatement packing unit.
As shown in Figs. 17 to 19, the plume-abatement packing unit 6006 is formed by heat exchange sheets 6001 stacked repeatedly, the bottom part of the plume-abatement packing unit is an inverted trapezoidal structure 6007, and adjacent heat exchange sheets are supported and separated from each other by vertical guide protrusions 6004 at the upper part, forming a dry cold airflow channel and a wet hot airflow channel.
The two sides of the inverted trapezoidal structure 6007 are inclined edges, and a water baffle and collection structure 6010 is arranged near the inclined edge of one side in the wet hot airflow channel, vertical guide protrusions 6004 are arranged on the upper part of the heat exchange sheet 6001, and the convex or concave shapes of adjacent vertical guide protrusions 6004 on the heat exchange sheet 6001 are opposite to each other in direction. The heat exchange sheet 6001 is provided with inclined and intermittent oblique guide protrusions 6008 at the inverted trapezoidal structure 6007, the direction of inclination of the oblique guide protrusions 6008 is the same as that of the inclined edges on the two sides of the inverted trapezoidal structure 6007, and the convex or concave shapes of the oblique guide protrusions in different directions of inclination are opposite to each other in direction.
Wet hot air is introduced into the plume-abatement packing unit 6006 from the wet hot air inlet 6002, and the accumulated liquid produced or captured by the plume-abatement packing unit 6006 flows out of the liquid collection outlet 6002 into the water collection channel. Cold air is introduced into the plume-abatement packing unit from the dry cold airflow inlet, and the liquid seal port 6003 at the lower part of the plume-abatement packing material is sealed by the liquid in the water collection channel to prevent air channeling between the cold air and the hot air.
The upper part and lower part of the heat exchange sheets 6001 of the plume-abatement packing unit 6006 are provided with upper spoilers 6005 and spoilers of inverted trapezoidal structures 6009 to enhance the heat exchange effect, besides the above-mentioned structures.
In the water collection and plume-abatement tower in the present disclosure, cold air in the atmospheric environment in a cold season enters the dry cold airflow channel through the louver, and flows into the water collection and plume-abatement packing material unit through the dry cold airflow inlet; the wet hot air carrying spray droplets from the water-sprayed packing layer enters the hot air channel, flows to the wet hot airflow inlet through the hot air channel, and enters the water collection and plume-abatement packing material. After entering the water collection and plume-abatement packing material, the wet hot air carrying spray droplets passes through the water baffle and collection structure first, and the wet hot air carrying spray droplets is baffled by the water baffle and collection structure. In the wet hot air baffling process, owing to the fact that the density of the spray droplets carried in the wet hot air is much higher than that of the wet hot air, the spray droplets have higher inertia; the spray droplets hit the windward side of the water baffle and collection structure, the spray droplets carried in the wet hot air are captured and removed by the water baffle and collection structure, and flow into the spray droplet accumulation and collection area of the water collection channel along the windward side of the water baffle and collection structure under the action of gravity.
After the spray droplets are removed, the wet hot air further flows into the hot channel of the water collection and plume-abatement packing material from the water baffle and collection structure, and exchanges heat with the cold air entering the cold channel through the air inlet of the cold channel via the heat exchange sheets, and the wet hot air is condensed. Owing to the heat exchange with the cold air, the temperature of the wet hot air drops, condensed water precipitates from the saturated wet hot air as the temperature drops, and the condensed water adheres to the heat exchange sheets and is carried by the wet hot air. The wet hot air carrying the condensed water is guided by the oblique guide channel into the upper part of the inverted trapezoidal structure of the water collection and plume-abatement packing material, and changes its flow direction in the process. Owing to the inertia difference resulted from the density difference, the condensed water carried by the wet hot air hits the vertical guide channel due to inertia, and the condensed water droplets carried in the wet hot air are captured by the vertical guide channel. The condensed water droplets adhering to and captured by the heat exchange sheets in the hot channel flow along the vertical guide channel and the oblique guide channel under the action of gravity, flow to the upper part through the gaps of the oblique guide channel, and enter the condensed water accumulation and collection area of the water collection channel.
After the heat exchange between the cold airflow and the hot airflow in the water collection and plume-abatement module, the external dry cold air is heated up and its temperature rises, while the temperature of the wet hot air drops; finally, the cooled wet hot air and the heated dry cold air leave the water collection and plume-abatement packing material and are mixed into unsaturated air, which is discharged out of the tower by the blower fan. Thus, a purpose of water collection and plume abatement is achieved.
The operation mode of the water collection and plume-abatement cooling tower in the present disclosure may be a water collection and plume-abatement operation mode or a thermal operation mode, depending on the operation season and load of the water collection and plume-abatement cooling tower. In the water collection and plume-abatement mode, a part of external cold air is directly introduced into the water collection and plume-abatement packing material in the tower to realize water collection and plume-abatement in the cooling tower. In the thermal operation mode, all the external cold air passes through the water-sprayed packing material, and the cooling tower has maximum circulating water cooling capacity.
In the water collection and plume-abatement operation mode, the circulating hot water is uniformly sprayed on the water-sprayed packing material through a circulating hot water spray header, and the external dry cold air is driven by the blower fan and flows into the tower through the air inlet of water-sprayed packing material at the lower part of the tower body, flows upward through the water-sprayed packing material, and contacts with the circulating hot water sprayed downward from above the water-sprayed packing material in a counter-current manner, and transfers heat and mass on the surface of the water-sprayed packing material; thus, the circulating hot water is cooled, and flows into the water collection tank below the water-sprayed packing material; the external dry cold air passing through the water-sprayed packing material is heated up into saturated wet hot air and leaves the water-sprayed packing material, flows into the wet hot air channel, and then flows into the hot channel of the plume-abatement packing material through the wet hot air channel. The partitions and the air dampers form a cold air channel; under a sucking effect of the blower fan, the external dry cold air is introduced through the louver into the cold air channel, and then flows into the cold channel of the plume-abatement packing material. In the plume-abatement packing material, the airflow passes through the water baffle and collection structure first, and the spray droplets carried in the airflow are collected under the action of inertia force, and flow to the spray droplet accumulation and collection area of the water collection channel under the action of gravity, and then return to the tower; the airflow further flows into the heat exchange sheets; the cold channel and the hot channel are arranged at an interval in the plume-abatement packing material, and inter-wall heat transfer happens via the heat exchange sheets; thus, the wet hot air is cooled, while the temperature of the dry cold air rises. The water droplets condensed from the wet hot air are captured by the vertical guide channel and the heat exchange sheets, and guided through the oblique guide channel into the condensed water accumulation and collection area of the partitioned water collection channel; the condensed water collected in the condensed water accumulation and collection area contains little salt and can be used as a feed for the desalted water device or directly used as desalted water if it meets the requirement; alternatively, this part of condensed water may be returned to the tower. The heated dry cold air and the condensed wet hot air leave the plume-abatement packing material and are mixed together into unsaturated air, which is discharged from the cooling tower by the blower fan.
In the thermal operation mode, plume abatement is not required in the cooling tower in summer; in addition, the cooling tower may have maximum cooling capacity in summer in view of the high load. The cooling tower operates as follows in the thermal operation mode: the circulating hot water is uniformly sprayed on the water-sprayed packing material through a circulating hot water spray header, and the external dry cold air is driven by the blower fan and flows into the tower at the lower part of the tower body, flows upward through the water-sprayed packing material, and contacts with the circulating hot water sprayed downward from above the water-sprayed packing material in a counter-current manner, and transfers heat and mass on the surface of the water-sprayed packing material; thus, the circulating hot water is cooled, and flows into the water collection tank below the water-sprayed packing material; the external dry cold air passing through the water-sprayed packing material is heated up into saturated wet hot air and leaves the water-sprayed packing material, then flows into the plume-abatement channel. In the plume-abatement channel, the air dampers rotate around their axis of rotation to a vertical state, while the louver connected to the cold air channel is in a closed state; the wet hot air from the water-sprayed packing material flows through the cold air channel and the wet hot air channel of the plume-abatement channel into the plume-abatement packing material, and both the cold channel and the hot channel of the plume-abatement packing material are used for the wet hot air. The wet hot air carries a lot of liquid water droplets; the water droplets flow in the cold channel and the hot channel of the plume-abatement packing material and are collected by the water baffle and collection structure, and the wet hot air leaving the plume-abatement packing material is discharged from the cooling tower by the blower fan.
While some preferred embodiments of the present disclosure are described above in detail with reference to the accompanying drawings, the present disclosure is not limited to those embodiments. Various simple variations may be made to the technical scheme of the present disclosure, including combinations of the specific technical features in any appropriate form, within the scope of the technical ideal of the present disclosure. To avoid unnecessary repetitions, various possible combinations are not described specifically in the present disclosure. However, such simple variations and combinations shall also be deemed as having been disclosed herein and falling in the scope of protection of the present disclosure.

Claims

A plume-abatement packing unit, comprising a plurality of heat exchange sheets (1001, 6001) that are stacked, with side edges (1028) of adjacent heat exchange sheets (1001, 6001) hermetically connected with each other, so as to form dry cold airflow channels and wet hot airflow channels which are alternately distributed along a stacking direction and capable of realizing inter-wall heat exchange by means of the heat exchange sheets (1001, 6001), wherein the lower part of each heat exchange sheet (1001, 6001) is formed into an inverted trapezoidal structure (1026, 5007, 6007), and adjacent heat exchange sheets (1001, 6001) are alternately sealed and connected at inclined edges (1012) on two sides of the inverted trapezoidal structure (1026, 5007, 6007), so that dry cold airflow inlets (1025, 5005) in communication with the dry cold airflow channels and wet hot airflow inlets (1022, 5001) in communication with the wet hot airflow channels are alternatively formed on two opposite sides, and liquid collection outlets (1023, 5002, 6002) in communication with the wet hot airflow channels are formed at bottom short edges (1011), and water collection and guide structures capable of guiding at least part of the water carried in an airflow introduced from the wet hot airflow inlets (1022, 5001) and/or generated by condensation of the airflow to the liquid collection outlets (1023, 5002, 6002) are formed on the sides of the heat exchange sheets (1001, 6001) facing the wet hot airflow channels.
The plume-abatement packing unit of claim 1, wherein the water collection and guide structure comprises guide protrusions protruding from the heat exchange sheets (1001, 6001) into the wet hot airflow channels, and each guide protrusion comprises an oblique guide protrusion (1004, 6008) that extends obliquely upward and intermittently in the inverted trapezoidal structure (1026, 5007, 6007) in the direction of the airflow from the wet hot airflow inlets (1022, 5001) to the wet hot airflow channels; condensed water generated by the condensation of the airflow introduced from the wet hot airflow inlets (1022, 5001) is guided by the oblique guide protrusions (1004, 6008) and falls to the liquid collection outlets (1023, 5002, 6002) through gaps (1030) between adjacent oblique guide protrusions (1004, 6008).
The plume-abatement packing unit of claim 2, wherein the guide protrusion further comprises a vertical guide protrusion (1002, 6004) that extends vertically upward from a top end of the oblique guide protrusion (1004, 6008), and the guide protrusion abuts against another adjacent heat exchange sheet (1001, 6001) in the wet hot airflow channel.
The plume-abatement packing unit of claim 2, wherein the water collection and guide structure comprises a parallel folded sheet structure formed on a main body part of the heat exchange sheet (1001, 6001) above the inverted trapezoidal structure (1026, 5007, 6007), and adjacent heat exchange sheets (1001, 6001) are formed with upper folded sheet areas (5008) extending in parallel with each other at the main body part, so that the airflow introduced from the wet hot airflow inlets (1022, 5001) is deflected repeatedly when it flows through the upper folded sheet areas (5008).
The plume-abatement packing unit of any of claims 1 to 4, wherein the water collection and guide structure comprises a water baffle and collection structure (1003, 6010) that is formed at a position on the heat exchange sheets (1001, 6001) near the wet hot airflow inlets (1022, 5001) and extends in a direction parallel to the inclined edge (1012) of the inverted trapezoidal structure (1026, 5007, 6007) on the side of the wet hot airflow inlets (1022, 5001), and the water baffle and collection structure (1003, 6010) is formed in a way that the flow direction of the airflow introduced from the wet hot airflow inlets (1022, 5001) is changed in the wet hot airflow channels, and the spray water carried in the airflow is directed to the liquid collection outlets (1023, 5002, 6002).
The plume-abatement packing unit of any of claims 1 to 5, further comprising a water collection channel (1005, 3003) that is arranged at the lower side of the heat exchange sheets (1001, 6001) and opposite to the bottom short edges (1011) of the inverted trapezoidal structures (1026, 5007, 6007).
The plume-abatement packing unit of claim 6, wherein the water collection channel (1005, 3003) has a condensed water accumulation and collection area (1017) for collecting the condensed water generated by the condensation of the airflow introduced from the wet hot airflow inlets (1022, 5001) and a spray droplet accumulation and collection area (1018) for collecting the spray water carried in the airflow introduced through the wet hot airflow inlets (1022, 5001), and the spray droplet accumulation and collection area (1018) is spaced apart from the condensed water accumulation and collection area (1017).
The plume-abatement packing unit of any of claims 1 to 7, wherein adjacent heat exchange sheets (1001, 6001) form liquid seal ports (1024, 5003, 6003) that are in communication with the dry cold airflow channels at the bottom short edges (1011) and alternatively distributed with the liquid collection outlets (1023, 5002, 6002) in the stacking direction of the heat exchange sheets (1001, 6001), and water collection and guide structures that are the same as those in the wet hot airflow channels are formed on the sides of the heat exchange sheets (1001, 6001) facing the dry cold airflow channels, and the water collection and guide structures are arranged in a way that at least part of the water carried in the airflow introduced from the dry cold airflow inlets (1025, 5005) and/or generated by the condensation of the airflow is guided to the liquid seal ports (1024, 5003, 6003).
The plume-abatement packing unit of any of claims 1 to 8, wherein top edges of the heat exchange sheets (1001, 6001) are formed as horizontal straight edges or downwardly recessed multi-segment edges, and adjacent heat exchange sheets (1001, 6001) form cold channel outlets (1019) that are alternately distributed in the stacking direction and in communication with the dry cold airflow channels and hot channel outlets (1020) that are in communication with the wet hot airflow channels across the length of the top edges.
The plume-abatement packing unit of any of claims 1 to 9, wherein the top edges of the heat exchange sheets (1001, 6001) extend along a wavy line respectively, and adjacent heat exchange sheets (1001, 6001) are connected with each other at peaks/valleys, so as to form cold channel outlets (1019) that are alternately distributed in the stacking direction and in communication with the dry cold airflow channels and hot channel outlets (1020) that are in communication with the wet hot airflow channels across the length of the top edges; and the cold channel outlets (1019) and the hot channel outlets (1020) form cellular top outlets (3002, 4002).
The plume-abatement packing unit of any of claims 1 to 10, wherein the heat exchange sheets (1001, 6001) are formed with columnar supports (5009) that extend in the dry cold airflow channels and/or the wet hot airflow channels and abut against adjacent heat exchange sheets (1001, 6001).
A plume-abatement cooling tower, comprising a tower body (2011), and a plume-abatement packing layer (2013), a spraying unit (2003) and a water-sprayed packing layer (2002) that are arranged in the tower body (2011) from top to bottom, wherein the plume-abatement packing layer (2013) comprises a plurality of plume-abatement packing units (1027, 3001, 4001, 5006, 6006) of any of claims 1 to 11, which are connected with each other on their sides; the tower body (2011) is formed with a cooling tower air inlet (2001) located at a lower side of the water-sprayed packing layer (2002) and a plurality of dry cold air channels (2005) that are located between the plume-abatement packing layer (2013) and the spraying unit (2003) and in communication with the dry cold airflow inlets (1025, 5005) respectively; and wet hot air channels (2006) that enable a spray liquid evaporated by the water-sprayed packing layer (2002) to flow to the wet hot airflow inlets (1022, 5001) are provided between adjacent dry cold air channels (2005).