A refrigerant-free cooling method for a bopet process cooling water system

Abstract

The present application relates to the field of refrigerant-free cooling technology of BOPET process cooling water system, in particular to a refrigerant-free cooling method for BOPET process cooling water system, comprising the following steps: a temperature detector starts to detect the return water temperature of a return water device and the outdoor atmospheric temperature; after the detection is completed, the on-off of the corresponding valve is controlled. The refrigerant-free cooling method for BOPET process cooling water system detects the return water temperature of the return water device and the outdoor atmospheric temperature through a temperature sensor, when the outdoor atmospheric temperature is higher than the set difference of the return water temperature of the return water device, the water chilling unit is started, the associated valve is opened, and the associated valve of the refrigerant-free cooling heat exchanger is closed; when the outdoor atmospheric temperature is lower than the set difference of the return water temperature of the return water device, the water chilling unit is stopped, the associated valve is closed, and the associated valve of the refrigerant-free cooling heat exchanger is opened, the process cooling water is switched to the refrigerant-free system operation mode for continuous operation, and the purpose of energy saving and consumption reduction is achieved.

Description

Technical Field

[0001] This invention relates to the field of refrigerant-free cooling technology for BOPET process cooling water systems, specifically a refrigerant-free cooling method for BOPET process cooling water systems. Background Technology

[0002] BOPET, or biaxially oriented polyester film, is a widely used high-performance film. Its processing flow is as follows: polyester melt casting – cooling – longitudinal stretching – transverse stretching – winding. The cooling process, which works in conjunction with the casting, involves a chiller roller cooling step. The polyester melt, reaching temperatures of over 260 degrees Celsius, is cast onto a chiller roller at a temperature of 19–25 degrees Celsius, forming a thick sheet. The heat carried by the high-temperature melt is conducted through surface heat exchange to the process cooling water within the chiller roller, and then the process cooling water circulation system transfers the heat to the environment. The heat from the chiller roller cooling system is typically cooled by a closed-loop chilled water supply system consisting of a plate heat exchanger, a circulating water pump, and a chiller unit.

[0003] The heat from the heated chilled water is then carried to the atmosphere by the cooling tower of the chiller unit, completing the final heat exchange. Under the traditional quench roller cooling process conditions, the inlet water temperature of the quench roller process is 19-25℃, the outlet water temperature is 22-28℃, the inlet and outlet water temperature difference is maintained at 3℃, the circulation water volume is 200-250t / h, and the heat to be exchanged is 600,000-750,000 kcal, or 700-870 kW. A chiller unit that provides cooling throughout the year is required to provide the cold source, and the heat is transferred through the heat exchanger HEX-1. Based on the chiller unit's net energy efficiency ratio of 5.5, the required power consumption is approximately 130-160 kW / h. Summary of the Invention

[0004] The purpose of this invention is to provide a refrigerant-free cooling method for the cooling water system of the BOPET process, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a refrigerant-free cooling method for a BOPET process cooling water system, comprising the following steps:

[0006] S1: Temperature detection

[0007] The temperature detector starts detecting the return water temperature of the return water unit and the outdoor ambient temperature; after completing the detection, it controls the opening and closing of the corresponding valve.

[0008] S2: Cooling water delivery

[0009] After the corresponding valve is opened, the cooling water inside the cooling water pool will be transported by the pump and delivered to the interior of the chiller or the heat exchanger without a refrigeration unit, where it will be cooled.

[0010] S3: Heat Absorption

[0011] The cooled water, after being cooled, is then pumped to the interior of the quench roll of the casting machine, where it absorbs the heat inside the quench roll.

[0012] S4: Reflux

[0013] When the cooling process absorbs the heat from the cooling rollers of the casting machine, it will heat up. The heated material will then be transported through pipes to the interior of the open cooling tower for further cooling. After cooling is complete, it will be transported to the interior of cooling water tank two.

[0014] Preferably, the temperature detector in S1 detects the return water temperature of the return water unit and the outdoor air temperature. When the outdoor air temperature is higher than the set difference between the return water temperature and the return water temperature, the chiller unit starts, the associated valves open, and the associated valves of the heat exchanger without refrigerant close. When the outdoor air temperature is lower than the set difference between the return water temperature and the return water temperature, the chiller unit stops, the associated valves close, and the associated valves of the heat exchanger without refrigerant open. The process cooling water switches to the refrigerant-free system operation mode and continues to operate, thereby achieving the purpose of energy saving and consumption reduction.

[0015] Preferably, the cooling water inside the cooling water tank in S2 is transported to the interior of the chiller unit for cooling in summer and to the interior of the heat exchanger without a refrigeration unit for heat exchange in winter. After the heat exchange is completed, it is transported to the interior of the quenching roller of the casting machine for cooling treatment.

[0016] Preferably, the S3 cooling water tank is connected to the casting machine's quenching roller via a pipeline, which facilitates the delivery of cooling water from the cooling water tank to the inside of the casting machine's quenching roller, thereby completing the heat exchange and cooling of the casting machine's quenching roller.

[0017] Preferably, in S4, the cooling heat exchanger without a refrigeration unit and the chiller are connected to the open cooling tower through pipes. After the cooling roller of the casting machine is cooled, the cooling water that causes the temperature to rise will enter the interior of the open cooling tower through pipes. The interior of the open cooling tower is equipped with a variable frequency cooling fan.

[0018] Preferably, the open cooling tower in S4 is connected to the second cooling water tank via a pipe. After cooling is completed, the cooling water will flow back into the interior of the second cooling water tank. The second cooling water tank is connected to the heat exchanger without a refrigeration unit and the chiller unit via pipes.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This refrigerant-free cooling method for the BOPET process cooling water system detects the return water temperature of the return water unit and the outdoor air temperature using a temperature sensor. When the outdoor air temperature is higher than the set difference between the return water temperature and the return water temperature, the chiller unit starts, the associated valves open, and the associated valves of the refrigerant-free cooling heat exchanger close. When the outdoor air temperature is lower than the set difference between the return water temperature and the return water temperature, the chiller unit stops, the associated valves close, and the associated valves of the refrigerant-free cooling heat exchanger open, switching the process cooling water to a refrigerant-free system operation mode for continuous operation, thereby achieving the goal of energy saving and consumption reduction.

[0021] 2. The refrigerant-free cooling method for the BOPET process cooling water system involves connecting a refrigerant-free cooling heat exchanger in parallel with the traditional chiller circulation system. When the outdoor temperature is lower than the process set value during winter and spring, the chiller is stopped, and the system circulating water is switched to the refrigerant-free cooling heat exchanger. The heat carried out by the process cooling water is transferred through heat exchange and then directly dissipated to the atmosphere through the cooling tower. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Diagram of the cooling water system for a traditional quench roller process;

[0024] Figure 2 Diagram of a refrigerant-free cooling and heat exchange system.

[0025] In the diagram: 1. Cooling water tank one; 2. Cooling heat exchanger without refrigeration unit; 3. Chiller unit; 4. Open cooling tower; 5. Casting machine quench roller; 6. Water return device; 7. Cooling water tank two. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] like Figure 1-2 As shown, the present invention provides a technical solution: a refrigerant-free cooling method for a BOPET process cooling water system, comprising the following steps:

[0029] S1: Temperature detection

[0030] The temperature detector starts monitoring the return water temperature of the return water unit 6 and the outdoor air temperature. When the outdoor air temperature is higher than the set difference between the return water temperature of the return water unit 6 and the outdoor air temperature, the chiller unit 3 starts, the associated valves open, and the associated valves of the heat exchanger without refrigerant closure close. When the outdoor air temperature is lower than the set difference between the return water temperature of the return water unit 6 and the outdoor air temperature, the chiller unit 3 stops, the associated valves close, and the associated valves of the heat exchanger without refrigerant closure open. The process cooling water switches to the refrigerant-free system operation mode and continues to operate, achieving the purpose of energy saving and consumption reduction.

[0031] S2: Cooling water delivery

[0032] After the corresponding valve is opened, the cooling water inside the cooling water tank 1 will be transported by the pump and delivered to the chiller unit 3 or the cooling heat exchanger 2 without a refrigeration unit. The cooling water inside the cooling water tank 1 will be delivered to the chiller unit 3 for cooling in summer and to the cooling heat exchanger 2 without a refrigeration unit for heat exchange in winter. After heat exchange, the cooling water will be delivered to the quench roller 5 of the casting machine for cooling treatment.

[0033] S3: Heat Absorption

[0034] The cooling water tank 1 is connected to the quench roller 5 of the casting machine through a pipeline, which facilitates the transportation of cooling water from the cooling water tank 1 to the interior of the quench roller 5. The cooled water is then pumped to the interior of the quench roller 5 and absorbs the heat inside the quench roller 5, thereby completing the heat exchange and cooling of the quench roller 5.

[0035] S4: Reflux

[0036] When the casting machine's cooling roller 5 absorbs heat during cooling, it will heat up. The heat exchanger 2 without a refrigeration unit and the chiller unit 3 are both connected to the open cooling tower 4 through pipes. After cooling the casting machine's cooling roller 5, the heated cooling water will enter the interior of the open cooling tower 4 through pipes. The open cooling tower 4 is equipped with a variable frequency cooling fan, which will then cool the water. After cooling, the water will be transported to the interior of the second cooling water tank 7. The open cooling tower 4 and the second cooling water tank 7 are connected through pipes. After cooling, the water will flow back into the second cooling water tank 7. The second cooling water tank 7 is connected to the heat exchanger 2 without a refrigeration unit and the chiller unit 3 through pipes.

[0037] The return water temperature of the return water unit 6 and the outdoor air temperature are detected by a temperature sensor. When the outdoor air temperature is higher than the set difference of the return water temperature of the return water unit 6, the chiller unit 3 starts, the associated valves open, and the associated valves of the refrigerant-free cooling heat exchanger 2 close. When the outdoor air temperature is lower than the set difference of the return water temperature of the return water unit 6, the chiller unit 3 stops, the associated valves close, and the associated valves of the refrigerant-free cooling heat exchanger 2 open. The process cooling water switches to the refrigerant-free system operation mode and runs continuously to achieve the purpose of energy saving and consumption reduction. In the traditional chiller unit 3 circulation system, the refrigerant-free cooling heat exchanger 2 is connected in parallel. In winter and spring, when the outdoor air temperature is lower than the process set value, the operation of the chiller unit 3 is stopped, and the system circulation water switches to the refrigerant-free cooling heat exchanger 2. The heat carried out by the process cooling water is transferred through heat exchange and directly dissipated to the atmosphere through the cooling tower.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A refrigerant-free cooling method for a BOPET process cooling water system, characterized in that, Includes the following steps: S1: Temperature detection The temperature detector starts detecting the return water temperature of the return water unit (6) and the outdoor air temperature; after the detection is completed, it controls the opening and closing of the corresponding valve; when the outdoor air temperature is higher than the set difference of the return water temperature of the return water unit (6), the chiller unit (3) starts, the associated valves open, and the associated valves of the heat exchanger without refrigerant (2) close; when the outdoor air temperature is lower than the set difference of the return water temperature of the return water unit (6), the chiller unit (3) stops, the associated valves close, and the associated valves of the heat exchanger without refrigerant (2) open, and the process cooling water switches to the refrigerant-free system operation mode and continues to run. S2: Cooling water delivery After the corresponding valve is opened, the cooling water inside the cooling water pool (1) will be transported by the pump and delivered to the interior of the chiller unit (3) or the heat exchanger without a refrigeration unit (2), and cooled inside the chiller unit (3) or the heat exchanger without a refrigeration unit (2). S3: Heat Absorption The cooling water that has been cooled is then pumped into the interior of the casting machine chiller roller (5) and absorbs the heat inside the casting machine chiller roller (5); S4: Reflux When the cooling water absorbs the heat inside the cooling roller (5) of the casting machine, it will heat up. At this time, the heated cooling water will be transported through the pipeline to the interior of the open cooling tower (4) for cooling. After cooling is completed, it will be transported to the interior of the second cooling water pool (7).

2. The refrigerant-free cooling method for a BOPET process cooling water system according to claim 1, characterized in that: The temperature detector in S1 detects the return water temperature of the return water device (6) and the outdoor atmospheric temperature.

3. The refrigerant-free cooling method for a BOPET process cooling water system according to claim 1, characterized in that: The cooling water inside the cooling water pool (1) in S2 will be transported to the interior of the chiller unit (3) for cooling in the summer.

4. The refrigerant-free cooling method for a BOPET process cooling water system according to claim 1, characterized in that: The cooling water tank (1) in S3 is connected to the quenching roller (5) of the casting machine through a pipeline.

5. A refrigerant-free cooling method for a BOPET process cooling water system according to claim 1, characterized in that: The heat exchanger (2) without a refrigeration unit and the chiller unit (3) in S4 are connected to the open cooling tower (4) through pipes. The open cooling tower (4) is equipped with a variable frequency cooling fan.

6. A refrigerant-free cooling method for a BOPET process cooling water system according to claim 1, characterized in that: The open cooling tower (4) in S4 is connected to the second cooling water tank (7) through a pipe. The second cooling water tank (7) is connected to the heat exchanger without a refrigeration unit (2) and the chiller unit (3) through pipes respectively.

Images