Freon natural circulation cooling system for turbine

Abstract

The utility model discloses a freon natural circulation cooling system for turbine, including evaporimeter, condenser, evaporimeter is linked with condenser, and evaporimeter is located below condenser, and evaporimeter is used for converting freon from liquid state into gaseous state, the condenser be used for converting freon gaseous state into liquid state, and the shell of condenser is equipped with first heat transfer structure, and the shell of evaporimeter is equipped with second heat transfer structure.

Description

Technical Field

[0001] This invention relates to a Freon natural circulation cooling system for turbines. Background Technology

[0002] With the widespread application of high-performance turbomachinery in industrial settings such as chemical and energy sectors, key components (such as bearings, sealing systems, and lubrication systems) generate a large amount of heat during operation, necessitating efficient and reliable cooling systems to maintain stable operation. Currently, water-cooled cooling systems are commonly used in the industry, with a typical structure being a shell-and-tube cooler that uses circulating water as the cooling medium to remove waste heat generated during equipment operation through heat exchange.

[0003] Although water-cooled systems have a relatively mature structure and low initial investment, they have revealed numerous technical bottlenecks during long-term operation. First, cooling efficiency is easily affected by fluctuations in circulating water volume and temperature, especially under high load or high ambient temperature conditions, where cooling capacity decreases significantly, impacting turbine operational stability. Second, because shell-and-tube heat exchangers are in constant contact with the water medium, scaling and corrosion are highly likely, particularly in chlorine-containing conditions. Corrosion and perforation of the tubes not only lead to cooling failure but can also cause chlorine leakage, posing serious safety and environmental hazards. Furthermore, to ensure service life, traditional water-cooled heat exchangers typically need to be replaced every 1-2 years, resulting in high maintenance costs and long downtime, severely restricting the continuous and stable operation of the equipment.

[0004] In terms of system energy consumption, traditional water cooling systems require a large cooling water flow rate and usually rely on high-power water pumps to maintain circulation, resulting in high overall energy consumption and increased operating costs in the cooling process. Furthermore, their application is limited in some factory environments where water resources are scarce or where water treatment capabilities are not available.

[0005] In summary, existing water-cooling technologies are inadequate in terms of efficiency, stability, safety, and maintainability. There is an urgent need for an alternative technology that requires no external power, has a more compact structure, higher cooling efficiency, and good environmental performance, in order to meet the increasingly stringent requirements of modern turbine equipment for thermal management systems. Utility Model Content:

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a Freon natural circulation cooling system for turbines.

[0007] A Freon natural circulation cooling system for a turbine includes an evaporator and a condenser, the evaporator being connected to the condenser and located below the condenser. The evaporator is used to convert Freon from a liquid state to a gaseous state, and the condenser is used to convert Freon from a gaseous state to a liquid state. The condenser shell is provided with a first heat exchange structure, and the evaporator shell is provided with a second heat exchange structure.

[0008] Furthermore, both the first and second heat exchange structures exchange heat with Freon through a partition wall heat exchange method.

[0009] Furthermore, the first heat exchange structure includes a tube side, in which circulating cooling water flows, and Freon flows in the shell side between the tube side and the condenser shell.

[0010] Furthermore, the second heat exchange structure includes chlorine gas, a main heat exchange module, a secondary cooler, and a freezer. The main heat exchange module, the cooler, and the freezer are connected in series via pipelines, with chlorine gas flowing through them. Freon exchanges heat with chlorine gas in the main heat exchange module, and circulating cooling water is installed in the secondary cooler.

[0011] Furthermore, the pipeline is equipped with several control valves.

[0012] Furthermore, the Freon is tetrafluoroethane (R134a).

[0013] Furthermore, the condenser and the first heat exchange structure are made of Q345R.

[0014] Furthermore, the evaporator and the second heat exchange structure are made of corrosion-resistant carbon steel.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0016] First, the system employs a compressor- and pump-free natural thermosiphon circulation method, avoiding the high energy consumption and maintenance burden associated with traditional compressor refrigeration. The entire cooling process relies entirely on the heat absorption of Freon's vaporization in the evaporator and the heat release and condensation in the condenser, as well as natural reflux driven by density difference. This significantly reduces energy consumption and noise during system operation and minimizes the risk of downtime due to mechanical failure.

[0017] Secondly, through the latent heat transfer mechanism of phase change, Freon can efficiently transfer cooling capacity within a unit volume, enabling the cooling system to improve overall heat treatment capacity without increasing equipment volume, resulting in a more compact and efficient system structure. Simultaneously, Freon's low boiling point and strong thermal stability allow it to naturally undergo phase change within the turbine's operating temperature range, effectively reducing temperature fluctuations in key components and ensuring long-term stable equipment operation.

[0018] Furthermore, the system is designed as a closed-loop system, with Freon flowing entirely within a sealed environment and without contact with the outside, greatly reducing the risk of refrigerant leakage and environmental pollution, and possessing excellent environmental protection characteristics and operational safety. In terms of heat exchanger materials, fluorine-resistant and chlorine-corrosion-resistant materials are used, further enhancing equipment lifespan and system stability.

[0019] Finally, this utility model system has a simple structure, operates quietly, and is easy to maintain, making it particularly suitable for industrial scenarios that are sensitive to noise or require long-term continuous operation. Overall, this technical solution significantly reduces system energy consumption, failure rate, and maintenance costs while improving cooling efficiency, demonstrating broad application prospects and good industrialization value. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a Freon natural circulation cooling system used in turbines;

[0021] Figure 2 This is the schematic diagram of the second heat exchanger;

[0022] In the diagram, 1 is the condenser, 2 is the evaporator, 3 is the main heat exchange module, 4 is the secondary cooler, and 5 is the freezer. Detailed Implementation

[0023] To enhance understanding of this utility model, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. These embodiments are only used to explain the present utility model and do not constitute a limitation on the scope of protection of the present utility model.

[0024] A Freon natural circulation cooling system for a turbine includes an evaporator 2 and a condenser 1. The evaporator 2 is connected to the condenser 1 and is located below the condenser 1. The evaporator 2 is used to convert Freon from a liquid state to a gaseous state, and the condenser 1 is used to convert Freon from a gaseous state to a liquid state. The shell of the condenser 1 is provided with a first heat exchange structure, and the shell of the evaporator 2 is provided with a second heat exchange structure.

[0025] This cooling system utilizes the principle of natural recirculation of Freon, that is, the Freon is automatically circulated within the system by density and gravity differences within a closed loop. When Freon absorbs heat and evaporates in evaporator 2, due to its lower vapor density, it rises into condenser 1 above it. In condenser 1, it releases heat and liquefies. The liquid Freon, due to its higher density, naturally falls back into evaporator 2 below, thus achieving a cooling medium circulation without mechanical drive. The first heat exchange structure is arranged inside the condenser 1 shell, exchanging heat with the incoming cooling water or other cooling medium to rapidly liquefy the high-temperature Freon. The second heat exchange structure is located inside the evaporator 2 shell, exchanging heat with the heat source to be cooled (such as key turbine components), thereby transferring heat to the Freon to promote its vaporization.

[0026] This system utilizes gravity and density difference to achieve natural circulation, avoiding the use of mechanical pumps and other power equipment, thus improving system reliability and reducing maintenance costs. The spatial arrangement of evaporator 2 and condenser 1 employs a height difference design, resulting in higher circulation efficiency, efficient refrigerant flow within the system, and a continuous and stable cooling process. The arrangement of the first and second heat exchange structures enhances heat exchange efficiency, achieving more effective energy conversion and improving turbine operational stability and overall cooling system performance. Furthermore, the natural circulation design offers lower energy consumption and better environmental adaptability, making it particularly suitable for applications in energy-sensitive or complex environments.

[0027] In one possible implementation, both the first heat exchange structure and the second heat exchange structure exchange heat with Freon through a partition wall heat exchange method.

[0028] Indirect heat exchange is a method of transferring heat from one fluid to another through a wall made of metal or other highly thermally conductive material. In this system, the first heat exchange structure is located inside the condenser shell 1, using a partition wall to separate the Freon from the cooling water and other media, condensing the gaseous Freon into a liquid state through heat transfer via the wall. The second heat exchange structure is located inside the evaporator 2, also employing an indirect heat exchange structure, allowing the high-temperature working fluid (such as chlorine) to transfer heat to the Freon through the heat exchange wall, causing it to vaporize. The entire heat exchange process is efficient and safe, avoiding direct contact between different media and improving the stability and reliability of system operation.

[0029] The use of a partitioned heat exchanger improves the system's sealing and safety, preventing contamination from the mixing of the cooling medium and Freon, while also facilitating control of heat exchange rate and efficiency. Furthermore, the partitioned structure facilitates maintenance, replacement, and cleaning, extending the system's service life and ease of maintenance. This heat exchange method offers advantages such as simple structure, low energy consumption, and strong adaptability, making it particularly suitable for applications requiring high heat transfer efficiency and high equipment pressure resistance.

[0030] In one possible implementation, the first heat exchange structure includes a tube side with circulating cooling water flowing inside, and Freon flowing in the shell side between the tube side and the condenser 1 shell.

[0031] In this embodiment, condenser 1 adopts a shell-side-tube-side structure. Cooling water flows in the tube side, exchanging heat with the Freon vapor in the shell side through the tube walls, causing the Freon to release heat and condense into liquid. Since the medium in the tube side is low-temperature circulating cooling water, its continuous flow can promptly remove heat and maintain the temperature difference, thereby enhancing condensation efficiency. The flow path of the Freon in the shell side and the geometry of the shell are optimized to ensure uniform heat exchange without dead zones.

[0032] This structure facilitates efficient phase change heat transfer, improves condensation efficiency, ensures stable refluxing of Freon to evaporator 2, and provides strong controllability of the cooling water circuit, allowing for precise temperature control by adjusting the flow rate. Furthermore, the shell-and-tube structure is mature and reliable, suitable for medium and large-scale cooling systems, facilitating maintenance and repair, and extending equipment lifespan.

[0033] In one possible implementation, the second heat exchange structure includes chlorine gas, a main heat exchange module 3, a secondary cooler 4, and a freezer 5. The main heat exchange module 3, the cooler, and the freezer 5 are connected in series via pipelines, with chlorine gas flowing through them. Freon exchanges heat with chlorine gas in the main heat exchange module 3, and circulating cooling water is provided in the secondary cooler 4.

[0034] This implementation improves the efficiency of evaporator 2 by constructing a multi-stage heat exchange path. Chlorine gas acts as a heat source, releasing heat to Freon in the main heat exchange module 3, causing Freon to vaporize. The chlorine gas is further cooled by the cooler and refrigerator 5, exchanging heat with Freon or circulating water during the gradual temperature decrease, achieving multi-stage temperature control and step-by-step heat recovery. The secondary cooler 4 is equipped with a cooling water circuit to further cool the chlorine gas, forming a stable chlorine gas circuit. The entire heat exchange process forms a highly efficient energy recovery and utilization system, improving overall thermal efficiency.

[0035] from Figure 2 As can be seen, chlorine (CL2) enters the system from the left side, first entering the main heat exchange unit TPJ E, where it undergoes initial cooling through heat exchange with the Freon medium. Subsequently, the chlorine enters the two-stage TPJ CL2 secondary cooler 4 for further heat exchange and cooling. Cooling water is input from CTW and returned from CTWR, completing the system's cooling capacity transfer, and finally enters the chiller 5.

[0036] This structure enables multi-stage utilization of chlorine heat, greatly improving the heat exchange efficiency of the Freon evaporator 2 and reducing system energy consumption. The main heat exchange module 3 realizes heat exchange in the high-temperature section, the secondary cooler 4 completes the end heat recovery, and the refrigerator 5 controls the chlorine return temperature. The system temperature control is precise and reliable, meeting the requirements of various operating conditions.

[0037] In one possible implementation, the pipeline is equipped with several control valves.

[0038] In one possible implementation, the Freon is tetrafluoroethane.

[0039] Tetrafluoroethane possesses excellent thermophysical properties, including a low boiling point, high latent heat, and superior chemical stability, enabling efficient evaporation and condensation even under low-pressure conditions. It rapidly absorbs heat and vaporizes in evaporator 2, and quickly releases heat and condenses in condenser 1, forming an effective natural circulation.

[0040] Using tetrafluoroethane as the working fluid offers advantages such as environmental friendliness, safety, and stability. It also exhibits low corrosivity to equipment materials, operates at a moderate pressure, and contributes to improving the safety and lifespan of the cooling system. Its high heat exchange efficiency further enhances the overall system energy efficiency ratio.

[0041] In one possible implementation, the condenser 1 and the first heat exchange structure are made of Q345R.

[0042] This material can effectively improve the structural strength and durability of condenser 1, reduce stress concentration caused by thermal expansion and contraction during operation, and enhance the long-term stability and safety of the equipment, making it suitable for continuous industrial operation scenarios.

[0043] In one possible implementation, the evaporator 2 and the second heat exchange structure are made of corrosion-resistant carbon steel.

[0044] Corrosion-resistant carbon steel improves the service life and safety factor of equipment, reduces the frequency of maintenance and replacement due to corrosion, and is suitable for stable operation in harsh industrial environments.

[0045] Working Principle: In the turbine cooling system proposed in this invention, Freon serves as the circulating working fluid. Utilizing its gas-liquid phase change characteristics, it forms a closed natural circulation loop between the evaporator 2 and the condenser 1, achieving efficient heat exchange and cooling of chlorine gas. This circulation does not rely on any compressor or mechanical pump; instead, it generates natural power through the density change of the working fluid itself and the height difference of the system, thus constituting an energy-saving, reliable, and environmentally friendly cooling mechanism.

[0046] During system operation, liquid Freon first flows from the outlet of condenser 1 into evaporator 2, located at the bottom of the system. In this evaporator, the liquid Freon absorbs sensible heat from chlorine gas. When the Freon temperature rises to its boiling point, a phase change process occurs, transforming it from liquid to gas. This phase change process is accompanied by the absorption of a large amount of latent heat, and the density of the evaporated Freon gas decreases significantly. Driven by thermosiphon action, it naturally rises to the condenser 1 at the higher level of the system.

[0047] Inside condenser 1, Freon gas undergoes indirect heat exchange with an external cooling medium (such as cooling water or air), releasing the heat absorbed in evaporator 2 and gradually condensing into a liquid state. During condensation, Freon changes from a gaseous state back to a liquid state, releasing latent heat of phase change. After condensation, the liquid Freon flows back to evaporator 2 along the return pipe due to gravity, completing a closed-loop natural cycle.

[0048] To maintain system continuity and efficiency, condenser 1 is positioned at a higher level in the system, while evaporator 2 is located at a lower level. The circulation piping uses a large-diameter design (e.g., DN50 or larger), and the height difference Δh between evaporator 2 and condenser 1 must meet the following conditions to reduce flow resistance and increase the natural circulation rate:

[0049] Δh≥ΔP / ρliquid g,

[0050] Δh is the vertical height difference between condenser 1 and evaporator 2 (unit: m);

[0051] ΔP is the total pressure loss of Freon in the circulation path, including pipeline friction, local resistance, etc. (unit: Pa);

[0052] ρ is the liquid density of Freon (unit: kg / m³). 3 );

[0053] g is the acceleration due to gravity, taken as 9.81 m / s². 2 .

[0054] Through this gas-liquid phase change and natural drive mechanism, Freon achieves a cyclic operation mode without compression, mechanical drive, or leakage, significantly reducing energy consumption and maintenance requirements while ensuring high cooling capacity transfer efficiency of the system.

[0055] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A Freon natural circulation cooling system for a turbine, characterized in that, It includes an evaporator and a condenser, which are connected and the evaporator is located below the condenser. The evaporator is used to convert Freon from a liquid state to a gaseous state, and the condenser is used to convert Freon from a gaseous state to a liquid state. The shell of the condenser is provided with a first heat exchange structure, and the shell of the evaporator is provided with a second heat exchange structure.

2. The circulating cooling system according to claim 1, characterized in that, Both the first and second heat exchange structures exchange heat with Freon through a partition wall heat exchange method.

3. The circulating cooling system according to claim 2, characterized in that, The first heat exchange structure includes a tube side, in which circulating cooling water flows, and Freon flows in the shell side between the tube side and the condenser shell.

4. The circulating cooling system according to claim 2, characterized in that, The second heat exchange structure includes chlorine gas, a main heat exchange module, a secondary cooler, and a freezer. The main heat exchange module, the cooler, and the freezer are connected in series through pipelines. Chlorine gas flows through the pipelines, and Freon exchanges heat with chlorine gas in the main heat exchange module. The secondary cooler is equipped with circulating cooling water.

5. The circulating cooling system according to claim 4, characterized in that, Several control valves are installed on the pipeline.

6. The circulating cooling system according to any one of claims 1-4, characterized in that, The Freon mentioned is tetrafluoroethane.

7. The circulating cooling system according to claim 3, characterized in that, The condenser and the first heat exchange structure are made of Q345R.

8. The circulating cooling system according to claim 4, characterized in that, The evaporator and the second heat exchange structure are made of corrosion-resistant carbon steel.

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