Air-cooled heat exchange device and method for regulating the same

Abstract

The application belongs to the technical field of heat exchange equipment, and discloses an air-cooled heat exchange device and a regulation and control method thereof. The device comprises a framework, a plurality of pipe bundles horizontally installed on the framework, the pipe bundles being heat exchange parts and having working medium channels inside, a plurality of lower air boxes installed below the pipe bundles, a plurality of air fans corresponding to the inlet ends of the lower air boxes and driving air into the lower air boxes, a plurality of upper air boxes installed above the pipe bundles and corresponding to the lower air boxes, a plurality of air ducts corresponding to the upper air boxes and communicating with the outlet ends of the upper air boxes, wherein the number of the air fans, the lower air boxes, the upper air boxes and the air ducts is equal, and the air fans, the lower air boxes, the upper air boxes and the air ducts are correspondingly communicated to form a plurality of independent ventilation air ducts. The regulation and control method is suitable for the device. The device has small influence from the external environment, high heat transfer coefficient and stable heat transfer, low operation energy consumption, small noise, long service life and wide application range, and has simple and stable structure and high safety.

Description

Technical Field

[0001] This invention belongs to the technical field of heat exchange equipment, specifically relating to an air-cooled heat exchange device and its control method. Background Technology

[0002] An air-cooled heat exchanger is a device that uses air as a cold flow to exchange heat with a working medium, which is a hot flow, to cool the working medium to the required temperature. Examples of applications include cooling industrial circulating water, bottom oil in petrochemical towers, and reflux oil.

[0003] Existing air-cooled heat exchangers are mainly classified into three types based on their ventilation methods: forced draft, induced draft, and natural convection. In forced draft air-cooled heat exchangers, the fan is typically located below the heat exchange tube bundle at the air inlet, blowing air into the tube bundle for heat exchange. In induced draft air-cooled heat exchangers, the fan is typically located above the heat exchange tube bundle at the air outlet, drawing air into the device for heat exchange with the tube bundle before exhausting the heated air. In natural convection air-cooled heat exchangers, a tall duct is typically installed above the heat exchange tube bundle, using the suction force of the duct to draw air into the device for heat exchange with the tube bundle. The three types of air-cooled heat exchangers mentioned above have relatively simple structures and can all use air to exchange heat with the working medium to achieve cooling of the working medium. However, some components (such as fans and tube bundles) are difficult to maintain, are easily affected by external factors and damage, and have poor operational stability. They also have certain limitations on ambient temperature, outlet temperature, and spatial layout, which makes different types of air-cooled heat exchangers have significant limitations in terms of usage environment and heat exchange conditions, and they cannot adapt well to complex and changing environmental conditions. Summary of the Invention

[0004] To address the shortcomings of existing air-cooled heat exchange devices, this invention aims to provide an air-cooled heat exchange device and its control method. This air-cooled heat exchange device is less affected by the external environment, has a high heat transfer coefficient and stable heat transfer, low operating energy consumption, low noise, long service life, few limitations, strong adaptability, and a wide range of applications; it also has a simple and stable structure and high safety.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An air-cooled heat exchange device, comprising:

[0007] Framework;

[0008] Several tube bundles are horizontally installed on the frame. The tube bundles are heat exchange parts and their interiors are working medium channels.

[0009] Several lower air boxes are installed below the tube bundle;

[0010] Several fans are installed at the inlet ends of several of the lower air boxes to drive air into the lower air boxes;

[0011] Several upper air boxes are installed on the tube bundle and are connected to several lower air boxes respectively;

[0012] Several air ducts are installed on several of the aforementioned upper air boxes and are connected to the outlet end of the upper air box;

[0013] The number of the aforementioned fans, lower air box, upper air box, and air duct is equal, and they are connected to form several independent ventilation ducts, through which air exchanges heat with the tube bundle.

[0014] In one embodiment of this application, a plurality of air valves are also included, each of which is installed at the outlet end of one of the air ducts and can adjust the opening amount of the air duct or close the outlet end of the air duct.

[0015] And / or, the outlet end of the ventilation duct is also provided with a protective net.

[0016] In one embodiment of this application, the air valve is a blade air valve with multiple adjustable blades inside;

[0017] And / or, the diameter of the air valve is 500~10000mm and the height is 120~1200mm.

[0018] In one embodiment of this application, the upper and lower air boxes have the same structure, both being conical transition structures with one end being round and the other end being square. The round end is connected to the air duct or the fan, and the square end is connected to the upper or lower side of the tube bundle.

[0019] In one embodiment of this application, the conical transition structure of the upper and lower air boxes includes a side plate, an end plate, a triangular connecting plate, and a top plate; one side of the side plate and the end plate after being spliced ​​together forms a square end; the other side of the triangular connecting plate and the side plate and the end plate after being spliced ​​together is adapted to be connected to the outer side of the top plate; the inner side of the top plate is a circular through hole, and the circular through hole is adapted to be connected to the inlet end of the air duct.

[0020] In one embodiment of this application, the side plate, end plate, triangular connecting plate and top plate are provided with folded edges at the connection points, and are connected by bolts during splicing.

[0021] In one embodiment of this application, the duct includes a plurality of duct sections connected in sequence.

[0022] In one embodiment of this application, the two ends of the duct section are provided with outward folded edges, and are connected by bolts during connection;

[0023] And / or, the outer side of the duct section has reinforcing ribs;

[0024] And / or, the diameter of the duct section is 500~10000mm, the height is 600~3000mm, and the overall height of the duct is 2000~15000mm.

[0025] In one embodiment of this application, the fan is driven by a variable frequency motor; it also includes a controller and several temperature detectors, the temperature detectors and the variable frequency motor being electrically connected to the controller and associated with each other.

[0026] A method for controlling an air-cooled heat exchanger as described above includes the following steps:

[0027] S100: Detect the ambient temperature T and the outlet temperature T1 of the working medium, and compare the ambient temperature T with the set temperatures t1 and t2; when T≥t1, proceed to step S200; when t2≤T<t1, proceed to step S300 or step S400; when T<t2, proceed to step S500.

[0028] S200. Turn on all the variable frequency motors of the aforementioned fans and run them at full speed, while simultaneously adjusting the flow rate V of the working medium flowing through the tube bundle. real-time The flow velocity V real-time ≤ The full-load flow rate value V set by the system operation max In order to control the outlet temperature T1 of the medium within the process set temperature range;

[0029] S300, Control the flow rate V real-time Approximately equal to the full-load flow rate value V max Adjust the frequency of the variable frequency motor driving the fan and reduce its speed to control the medium outlet temperature T1 within the process set temperature range;

[0030] S400, Control the flow rate V real-time Approximately equal to the full-load flow rate value V max Turn off the variable frequency motors of some of the fans, and turn on and run the variable frequency motors of the other fans at full speed to control the medium outlet temperature T1 within the process set temperature range.

[0031] S500, Control the flow rate V real-time Approximately equal to the full-load flow rate value V max All the variable frequency motors are turned off, and natural convection heat transfer is used to control the medium outlet temperature T1 within the process set temperature range.

[0032] If the medium outlet temperature T1 is lower than the minimum value of the process set temperature range, then the air valve on the air duct is controlled to reduce its opening amount until it is closed.

[0033] If the medium outlet temperature T1 is higher than the highest value of the process set temperature range, then proceed to step S300 or step S400.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. The air-cooled heat exchange device of this application has an upper air box and a lower air box on the upper and lower sides of the tube bundle, respectively. The tube bundle is not in direct contact with the outside, which can effectively block the influence of wind, sand, willow catkins, hail, rain, snow, and sunlight on the tube bundle, reduce the thermal resistance of dirt on the outside of the tube bundle, improve the heat transfer coefficient of the tube bundle, extend its service life, and make the heat exchange more stable. The fan is located at the air inlet and operates at atmospheric temperature, which is convenient for installation and maintenance, stable in operation, low in energy consumption, and long in service life. The air duct is provided, which has a suction effect and can maintain about 30% of the cooling load when the fan is stopped, achieving energy saving and heat reduction. The air-cooled heat exchange device of this application has a simple structure and compact design. It combines the advantages of existing blower-type, induced draft-type and natural convection-type air-cooled heat exchange devices and improves their respective disadvantages. It is easy to install and maintain, has a long service life, low energy consumption and low operating noise, small application limitations, strong adaptability and wide applicability. In addition, it forms several independent ventilation ducts that can work together to adapt to different heat exchange conditions and reduce energy consumption and noise.

[0036] 2. An air valve is installed at the outlet end of the air duct, which can regulate the air volume when the fan is stopped; the air valve is closed under low temperature conditions to keep warm and prevent freezing, thus preventing the working medium inside the tube bundle from freezing or becoming too cold; and it also blocks the influence of wind, sand, willow catkins, hail, rain, snow, and sunlight on the tube bundle, thus playing a protective role, ensuring safe operation, and further expanding the application range of the air-cooled heat exchange device.

[0037] 3. The upper and lower air boxes adopt a conical transition and are spliced ​​from plates. They are connected by folding and bolts. The structure has low ventilation resistance, uniform airflow distribution, high structural strength, and strong vibration resistance. The structure is simple and easy to mass-produce. Each component can be formed by sheet metal folding and bolted together, eliminating the need for welding, reducing labor intensity. In addition, the parts are highly interchangeable, making installation and transportation convenient.

[0038] 4. The air duct is composed of connected sections. The number of sections can be selected according to the design requirements of the air-cooled heat exchanger and the limitations of the installation site. It is highly adaptable and the sections are simple to form and can be mass-produced. The structure is strong and easy to install without welding, thanks to the folding and bolt connection.

[0039] 5. The control method of this application, when applied to the above-mentioned air-cooled heat exchange device, can give full play to the advantages of the air-cooled heat exchange device, adapt to different environmental conditions, and achieve low energy consumption and low noise operation. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a front view structural schematic diagram of the air-cooled heat exchange device of the present invention.

[0042] Figure 2 This is a side view of the air-cooled heat exchange device of the present invention.

[0043] Figure 3 This is a top view of the air-cooled heat exchange device of the present invention.

[0044] Figure 4 This is a three-dimensional structural diagram of the upper air box in this invention.

[0045] Figure label:

[0046] 100. Framework;

[0047] 200. Tubes;

[0048] 300. Lower air box; 310. Side plate; 320. End plate; 330. Triangular connecting plate; 340. Top plate;

[0049] 400. Fan; 410. Variable frequency motor;

[0050] 500. Top bellows;

[0051] 600. Air duct; 610. Protective net; 620. Air valve; 630. Air duct section. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0056] like Figures 1 to 3 As shown, an embodiment of the present invention provides an air-cooled heat exchange device, which includes a frame 100 that provides support and load-bearing function, a tube bundle 200 installed on the frame 100, an upper air box 500 and a lower air box 300 installed on the upper and lower sides of the tube bundle 200, a fan 400 installed under the lower air box 300, and a wind duct 600 installed on the upper air box 500, etc.

[0057] The tube bundle 200 comprises several units, which can be one or more, and the tube bundles 200 are horizontally laid and installed on the frame 100. Each tube bundle 200 has a medium inlet and a medium outlet, and its interior serves as a channel for the flow of the working medium; that is, the tube bundle 200 is the heat exchange component of the air-cooled heat exchange device. Fins may be installed on the outside of the tube bundle 200 to increase the heat exchange area.

[0058] The downwind box 300 includes several units, which can be one or more. The downwind box 300 is installed below the pipe bundle 200 and is connected and fixed to the pipe bundle 200 or to the frame 100.

[0059] There may be one or more fans 400. Each fan 400 is installed at the inlet end of the lower air box 300 and communicates with it; that is, the fan 400 is located at or below the lower air box 300. When there are multiple lower air boxes 300 and multiple fans 400, each fan 400 is installed in a one-to-one correspondence with a lower air box 300. The fans 400 are used to drive air to introduce outside air into the lower air box 300.

[0060] The upper wind box 500 may consist of one or more units. The upper wind box 500 is mounted on the pipe bundle 200 and is connected and fixed to the upper side of the pipe bundle 200 or to the frame 100. The upper wind box 500 and the lower wind box 300 are correspondingly connected; that is, when there are multiple upper wind boxes 500 and lower wind boxes 300, each upper wind box 500 and lower wind box 300 is connected in a one-to-one correspondence.

[0061] The ventilation duct 600 comprises several units, which can be one or more. The ventilation duct 600 is installed on top of the upper air box 500 and connected to the outlet end of the upper air box 500; when there are multiple ventilation ducts 600 and upper air boxes 500, each ventilation duct 600 is connected to an upper air box 500 in a one-to-one correspondence. The upper part of the ventilation duct 600 is the outlet end, which is equipped with a protective net 610 to effectively prevent debris from entering the ventilation duct 600 and ensure the normal operation of the ventilation duct 600 and its subordinate pipe bundle 200, fan 400, etc.

[0062] In an air-cooled heat exchanger, the number of fans 400, lower air box 300, upper air box 500, and air duct 600 are equal and connected sequentially from bottom to top. When there are multiple fans 400, lower air box 300, upper air box 500, and air duct 600, they are connected one-to-one to form multiple relatively independent ventilation ducts. Air passes through the ventilation ducts and exchanges heat with the working medium inside the tube bundle 200. For example, when the working medium is circulating water, the circulating water enters the tube bundle 200 through the medium inlet and exchanges heat with the air flowing through the ventilation duct through the side wall of the tube bundle 200, thereby cooling the circulating water. The cooled circulating water is then discharged from the medium outlet, completing the cooling process.

[0063] The air-cooled heat exchange device may include one ventilation channel or multiple independent ventilation channels; when there are multiple independent ventilation channels, the multiple ventilation channels are arranged neatly.

[0064] In one embodiment, the air-cooled heat exchange device further includes a plurality of air valves 620, the number of which is equal to the number of air ducts 600, and are installed at the outlet end of the upper part of the air ducts 600 to adjust the opening amount of the air ducts 600 or to close the outlet end of the air ducts 600.

[0065] Specifically, the damper 620 can be a vane damper, which has multiple adjustable vanes inside. By controlling the rotation of the vanes, the opening amount of the air duct 600 channel can be controlled or the outlet of the air duct 600 can be closed. The damper 620 can be controlled manually, pneumatically, or electrically.

[0066] The material of the damper 620 can be steel, aluminum, or non-metallic composite materials, preferably with a height of 120~1200mm and a diameter of 500~10000mm. Its diameter and height dimensions should be compatible with the dimensions of the air duct 600. The damper 620, when fully open, provides the same ventilation function as the air duct 600, increasing the heat exchange efficiency of the heat exchange device. Adjusting the opening degree of the damper 620 changes the ventilation effect, thus regulating the heat exchange efficiency. When the damper 620 is fully closed, the air intake at the bottom cannot be discharged through it, providing insulation and antifreeze protection, especially during low-temperature operation in winter. It also effectively blocks the effects of wind, sand, hail, rain, snow, sunlight, and flying pollen on the tube bundle 200, providing protection and ensuring safe operation.

[0067] like Figures 1 to 4 As shown, the upper air box 500 and the lower air box 300 have basically the same structure, both being conical transition structures. The upper air box 500 and the lower air box 300 are respectively positioned opposite each other on the upper and lower sides of the tube bundle 200. One end of their conical transition structure is circular, and the other end is square (rectangular or square). The circular end of the upper air box 500 is the outlet end, connected and communicating with the lower end of the air duct 600; the circular end of the lower air box 300 is the inlet end, connected and communicating with the fan 400; the square end of the upper air box 500 is connected to the upper side of the tube bundle 200, and the square end of the lower air box 300 is connected to the lower side of the tube bundle 200. That is, the tube bundle 200 is installed between the upper air box 500 and the lower air box 300, and the upper air box 500 and the lower air box 300 are connected in a one-to-one correspondence, allowing air to exchange heat with the working medium inside the tube bundle 200 within the space they form. The connection end with the tube bundle 200 is square, which allows for better assembly and installation, and better adapts to the structure of the tube bundle 200.

[0068] In one implementation, such as Figure 4 As shown, the conical transition structure of the upper air box 500 and the lower air box 300 includes side plates 310, end plates 320, triangular connecting plates 330, and top plates 340. These components are assembled together and connected by bolts. Each side plate 310 comprises at least two pieces, and each end plate 320 comprises at least two pieces. The side plates 310 and end plates 320 are joined to form four sides, with the side with the larger diameter forming the square end of the conical transition structure. Each triangular connecting plate 330 comprises at least four pieces, located at the junction of the side plates 310 and end plates 320. After being joined with the side plates 310 and end plates 320, the side with the smaller diameter of the triangular connecting plate 330 is fitted and connected to the outer side of the top plate 340. The outer side of the top plate 340 is preferably a regular octagonal structure, with concentric circular through holes on the inner side. These circular through holes are fitted and connected to the lower end of the air duct 600.

[0069] The edges of the side plate 310, end plate 320, triangular connecting plate 330, and top plate 340 are the connection points, each with a folded edge. During assembly, screw holes are made on the folded edges, and bolts are passed through these holes for connection and fixation. The side plate 310, end plate 320, triangular connecting plate 330, and top plate 340 are all equipped with reinforcing ribs, which can be formed by stamped convex strips, welded or bolted angle steel or channel steel, etc. The transitional conical structure of the upper air box 500 and lower air box 300 is simple in structure, with low ventilation resistance, uniform airflow distribution, high structural strength, and strong vibration resistance. The side plate 310, end plate 320, triangular connecting plate 330, and top plate 340 can all be formed by sheet metal folding, making manufacturing simple and suitable for modular mass production. The parts are highly interchangeable. Bolted connection installation eliminates the need for welding, simplifying installation.

[0070] like Figure 1 and Figure 2 As shown, in one embodiment, the ventilation duct 600 includes multiple ventilation duct sections 630, which are spliced ​​together. The diameter of a single ventilation duct section 630 is 500~10000mm, and the height is 600~3000mm. The overall height of the ventilation duct 600 is controlled within the range of 2000~15000mm.

[0071] Furthermore, the two ends of the duct section 630 are connection points, with outward-facing flanges at these points. During connection, the flanges are used in conjunction with bolts. The connection to the upper air box 500 also utilizes flanges and bolts, simplifying installation, eliminating the need for welding, and ensuring a robust structure. Reinforcing ribs are also provided on the outer side of the duct section, further enhancing its structural strength. The duct section 630 can be made of steel, aluminum, or non-metallic composite materials, and can be formed by rolling sheet material or spiral welding strip material, simplifying the forming process and facilitating mass production.

[0072] The 600-section air duct effectively eliminates the impact of hot air circulation at the outlet on the tube bundle heat exchange; it creates a significant pressure difference between the inlet and outlet, providing a certain suction effect and reducing operating energy consumption. Especially in low-temperature weather, it can maintain a certain cooling load, even up to about 30%, even when the unit is shut down. When assembled using 630-section air ducts, the number of sections can be selected according to the design requirements of the air-cooled heat exchanger or the limitations of the installation site. It has strong adaptability and applicability, and the air duct sections are simple to form and can be mass-produced. Through folding and bolt connection, the structure has high strength, requires no welding, and is easy to install.

[0073] The fan 400 is installed below the circular end of the lower air box 300 and is driven by the variable frequency motor 410. This air-cooled heat exchange device also includes a controller and several temperature detectors. These detectors are installed at the medium inlet and outlet of the tube bundle 200, outside the fan 400, and at the outlet end of the air duct 600, respectively, to detect the temperature of the working medium flowing in and out, the ambient temperature, and the air temperature at the outlet of the air duct 600. A regulating valve and a flow meter are also installed at the medium inlet and / or outlet of the tube bundle 200. The temperature detectors, variable frequency motor 410, air valve 620, regulating valve, and flow meter are all electrically connected to the controller, and the temperature detectors are associated with the variable frequency motor 410 and the air valve 620. This controller can be a PLC controller, which can intelligently control the operation of the variable frequency motor 410, air valve 620, regulating valve, etc., according to changes in ambient temperature, medium temperature, etc., further achieving low-energy consumption and low-noise operation.

[0074] In summary, the air-cooled heat exchange device of this application has an upper air box 500 and a lower air box 300 on the upper and lower sides of the tube bundle 200, respectively. The tube bundle 200 is not in direct contact with the outside, which can effectively block the influence of wind, sand, willow catkins, hail, rain, snow, and sunlight on the tube bundle 200, reduce the thermal resistance of dirt on the outside of the tube bundle 200, improve the heat transfer coefficient of the tube bundle 200, extend its service life, and make the heat exchange more stable. The fan 400 is located at the air inlet and operates at atmospheric temperature. It is easy to install and maintain, operates stably, has low energy consumption, and has a long service life. The air duct 600 is provided, which has a suction function and can be used when the fan 400 is stopped. The cooling load is maintained at approximately 30% during operation, achieving energy saving and noise reduction. The air duct 600 effectively eliminates the impact of hot air circulation at the outlet on the heat exchange effect of the tube bundle 200. The air valve 620 regulates airflow when the fan 400 is stopped. Closing the air valve 620 under low-temperature conditions provides insulation and antifreeze protection, preventing the working medium inside the tube bundle from freezing or becoming too cold. It also protects the tube bundle 200 from the effects of wind, sand, willow catkins, hail, rain, snow, and sunlight, ensuring safe operation and further expanding the applicability of the air-cooled heat exchange device. The air-cooled heat exchange device of this application has a simple and compact structure, combining the advantages of existing forced draft, induced draft, and natural convection air-cooled heat exchange devices while improving upon their respective disadvantages. It is easy to install and maintain, has a long service life, low energy consumption and low operating noise, minimal application limitations, and a wide range of applications. Furthermore, it forms several independent ventilation ducts that can work together to adapt to different working conditions, reducing energy consumption and noise.

[0075] This application also provides a method for controlling an air-cooled heat exchange device. This method is implemented based on the above-mentioned air-cooled heat exchange device and specifically includes the following steps:

[0076] Step S100: Detect the ambient temperature T and the working medium outlet temperature T1; the working medium is heat flow. Taking circulating water as an example, detecting the outlet temperature T1 means detecting the temperature of the circulating water discharged from the tube bundle outlet after heat exchange with air; compare the detected ambient temperature T with the preset temperatures t1 and t2 in the controller; where t1 is greater than t2, t1 is the boundary value of high ambient temperature, and t2 is the boundary value of low ambient temperature. The settings of t1 and t2 are calculated based on the design parameters and operating parameters of the air-cooled heat exchanger.

[0077] When T≥t1, perform step S200;

[0078] When t2≤T<t1, perform step S300 or step S400.

[0079] When T < t2, then proceed with step S500.

[0080] Step S200: Turn on all the fans 600 and control the variable frequency motor 410 driving the fans to run at full speed. At the same time, drive the air valve 620 to fully open so that the air-cooled heat exchange device runs at full load. Detect the medium outlet temperature T1 and control the medium outlet temperature T1 within the process set temperature range. The process set temperature range is the temperature range that the working medium needs to reach after heat exchange.

[0081] If the medium outlet temperature T1 is within the process set temperature range, then maintain the flow rate V of the working medium through the tube bundle 200. real-time Stabilize at the current value, or adjust to the full-load flow rate value V set by the system operation. max The flow rate V should be controlled. real-time ≤ Full load flow rate V max Normally, during system operation, the flow rate V of the working medium... real-time Roughly equal to the full-load flow rate V max ;

[0082] If the medium outlet temperature T1 is greater than the highest value of the process set temperature range, then adjust the flow rate V of the working medium flowing through the tube bundle 200. real-time Reduce flow velocity V real-time To control the medium outlet temperature T1 within the process set temperature range, and the working medium flow rate V real-time The adjustment range is 0~V max During this period, it is essential to ensure the safe and stable operation of the system, and the operating flow rate must not exceed the safe limit; of course, the system also has a preset minimum operating flow rate V. low When the flow velocity V real-time Below the flow rate V low If this occurs, the controller will issue an alarm and the machine will need to be stopped.

[0083] When T≥t1, the medium outlet temperature T1 will usually not be less than the minimum value of the process set temperature range. If the medium outlet temperature T1 is less than the minimum value of the process set temperature range, the controller will issue an alarm prompt (prompting the administrator to revise the preset parameters) and at the same time change to perform the operation of step S300 or S400.

[0084] Step S300: Control the flow rate V of the working medium through the tube bundle 200. real-time Stabilize at full load flow rate V max That is, controlling the flow rate V real-time Roughly equal to the full-load flow rate V max The operating frequency of the variable frequency motor 410 driving the fan 400 is adjusted so that the variable frequency motor 410 decelerates or stops, thereby controlling the medium outlet temperature T1 within the process set temperature range; during this operation, the air valve 620 is fully open.

[0085] When t2≤T<t1, the variable frequency motor 410 will not usually decelerate to a stop; if the variable frequency motor 410 stops and the medium outlet temperature T1 is still lower than the minimum value of the process set temperature range, the controller will issue an alarm prompt (prompting the management personnel to revise the preset parameters) and proceed to step S500.

[0086] Step S400: Control the flow rate V of the working medium through the tube bundle 200. real-time Stabilize at full load flow rate V max That is, controlling the flow rate V real-time Roughly equal to the full-load flow rate V max The variable frequency motor 410 driving the fan 400 is turned off, and the variable frequency motor driving the other fan 400 is turned on and runs at full speed. The turned-off and turned-on variable frequency motors are spaced apart to control the medium outlet temperature T1 within the process set temperature range. During this operation, the air valve 620 is fully opened.

[0087] Typically, the variable frequency motors are turned on and off in a certain ratio, such as a 1:1 ratio. Half of the variable frequency motors 410 are off, while the other half, spaced apart, run at full speed. This achieves energy saving and noise reduction through a combination of forced ventilation and natural convection, as well as by using forced ventilation to enhance natural convection in adjacent ventilation channels. Alternatively, the variable frequency motors can be turned on and off in ratios of 1:2, 1:3, or 1:4. The on / off ratio must be determined based on the actual operating conditions to control the medium outlet temperature T1 within the process setting temperature range. This step S400 is applicable to air-cooled heat exchangers with two or more ventilation ducts.

[0088] Step S500: Control the flow rate V of the working medium through the tube bundle 200. real-time Stabilize at full load flow rate V max That is, controlling the flow rate V real-time Roughly equal to the full-load flow rate V max Turn off all variable frequency motors 410, open the air valve 620, and use the suction force of the air duct 600 to control the medium outlet temperature T1 within the process set temperature range through natural convection heat exchange.

[0089] If the medium outlet temperature T1 is lower than the minimum value of the process set temperature range, i.e., the ambient temperature T is too low, and the working medium cools down too much due to complete natural air convection, then the control valve 620 will reduce its opening amount to reduce the amount of air flowing through. If the medium outlet temperature T1 is still lower than the minimum value of the process set temperature range, then the opening amount of the valve 620 will be further reduced until the valve 620 is completely closed, so that air no longer flows through the air-cooled heat exchanger. When the valve 620 is completely closed, it can provide insulation and protection for the tube bundle 200 inside the air-cooled heat exchanger to prevent freezing. If the medium outlet temperature T1 is still lower than the minimum value of the process set temperature range after the valve 620 is completely closed, the controller will issue an alarm, and the air-cooled heat exchanger needs to be shut down.

[0090] When T < t2, if the medium outlet temperature T1 is higher than the highest value of the process set temperature range during complete natural convection heat transfer, the controller will issue an alarm (prompting the administrator to revise the preset parameters) and change to perform step S300 or S400.

[0091] In summary, the control method for the air-cooled heat exchanger of this application fully leverages the advantages of the air-cooled heat exchanger to achieve energy saving, reduced consumption, and low-noise operation. By combining multiple control logics, it avoids situations where a single logic control cannot meet the actual process requirements, making the air-cooled heat exchanger less limited, more adaptable, and safer and more reliable in operation.

Claims

1. An air-cooled heat exchange device, characterized in that, include: Framework; Several tube bundles are horizontally installed on the frame. The tube bundles are heat exchange parts and their interiors are working medium channels. Several lower air boxes are installed below the tube bundle; Several fans are installed at the inlet ends of several of the lower air boxes to drive air into the lower air boxes; Several upper air boxes are installed on the tube bundle and are connected to several lower air boxes respectively; Several air ducts are installed on several of the aforementioned upper air boxes and are connected to the outlet end of the upper air box; The number of the aforementioned fans, lower air box, upper air box and air duct is equal, and they are connected to form several independent ventilation ducts, through which air exchanges heat with the tube bundle. It also includes several air valves, each of which is installed at the outlet end of an air duct and can adjust the opening amount of the air duct or close the outlet end of the air duct. The fan is driven by a variable frequency motor; it also includes a controller and several temperature detectors, which are respectively installed at the medium inlet and medium outlet of the tube bundle. The temperature detectors and the variable frequency motor are all electrically connected to the controller, and the temperature detectors, the variable frequency motor, and the air valve are associated with each other. The upper and lower air boxes have the same structure, both being conical transition structures with one end being round and the other end being square. The round end is connected to the air duct or fan, and the square end is connected to the upper or lower side of the tube bundle. The conical transition structure of the upper and lower air boxes includes side plates, end plates, triangular connecting plates, and a top plate; one side of the side plates and end plates after splicing forms a square end; the other side of the triangular connecting plate, side plates, and end plates after splicing is adapted to connect with the outer side of the top plate; the inner side of the top plate has a circular through hole, which is adapted to connect with the air duct inlet end; the connection points of the side plates, end plates, triangular connecting plates, and top plate are provided with folded edges, and are connected by bolts during splicing; The ventilation duct comprises multiple ventilation duct sections connected in sequence; the two ends of each ventilation duct section are provided with outward folded edges and are connected by bolts.

2. The air-cooled heat exchange device according to claim 1, characterized in that, The outlet end of the ventilation duct is also equipped with a protective net.

3. The air-cooled heat exchange device according to claim 1, characterized in that, The air valve is a blade air valve with multiple adjustable blades inside; And / or, the diameter of the air valve is 500~10000mm and the height is 120~1200mm.

4. The air-cooled heat exchange device according to claim 1, characterized in that, The outer side of the ventilation duct section has reinforcing ribs; And / or, the diameter of the duct section is 500~10000mm, the height is 600~3000mm, and the overall height of the duct is 2000~15000mm.

5. A method for controlling an air-cooled heat exchange device as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S100: Detect the ambient temperature T and the outlet temperature T1 of the working medium, and compare the ambient temperature T with the set temperatures t1 and t2; when T≥t1, proceed to step S200; when t2≤T<t1, proceed to step S300 or step S400; when T<t2, proceed to step S500. S200. Turn on all the variable frequency motors of the aforementioned fans and run them at full speed, while simultaneously adjusting the flow rate V of the working medium flowing through the tube bundle. real-time The flow velocity V real-time ≤ The full-load flow rate value V set by the system operation max In order to control the outlet temperature T1 of the working medium within the process set temperature range; S300, Control the flow rate V real-time Approximately equal to the full-load flow rate value V max Adjust the frequency of the variable frequency motor driving the fan and reduce its speed to control the outlet temperature T1 of the working medium within the process set temperature range; S400, Control the flow rate V real-time Approximately equal to the full-load flow rate value V max Turn off the variable frequency motors of some of the fans, and turn on and run the variable frequency motors of the other fans at full speed to control the outlet temperature T1 of the working medium within the process set temperature range. S500, Control the flow rate V real-time Approximately equal to the full-load flow rate value V max All the variable frequency motors are turned off, and natural convection heat transfer is used to control the outlet temperature T1 of the working medium within the process set temperature range. If the outlet temperature T1 of the working medium is lower than the minimum value of the process set temperature range, the air valve on the air duct is controlled to reduce its opening amount until it is closed. If the outlet temperature T1 of the working medium is higher than the highest value of the process set temperature range, then proceed to step S300 or step S400.

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