Receiving station cold energy recovery system
By designing a reboiler and heater interconnected structure in the cold energy recovery system of the receiving station, the problem of chilled water freezing during heat exchange between low-temperature liquefied hydrocarbons or low-temperature liquid ammonia and circulating water or chilled water is solved, realizing flexible control of medium flow and safe and stable cold energy recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA NAT AIR SEPARATION ENG CO LTD
- Filing Date
- 2025-08-06
- Publication Date
- 2026-07-21
AI Technical Summary
In the existing technology, during the heat exchange process between cryogenic liquefied hydrocarbons or cryogenic liquid ammonia and circulating water or chilled water, the chilled water is prone to freezing, which can lead to blockage of the heat exchange tubes, posing a safety hazard and lacking operational flexibility.
The receiving station cold energy recovery system, consisting of a reboiler and a heater, utilizes the cold energy of cryogenic liquefied hydrocarbons or cryogenic liquid ammonia to cool circulating water or chilled water through the interconnected design of the reboiler shell side and the heater tube side. It also utilizes the heat energy of the circulating water or chilled water to reheat the liquefied hydrocarbons or ammonia, thus avoiding the freezing of chilled water and enhancing operational flexibility.
It effectively eliminates the freezing phenomenon of chilled water, enhances the working flexibility of the medium flow rate from zero to the maximum rated value, is easy to operate and maintain, and avoids the occurrence of safety accidents.
Smart Images
Figure CN224534860U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a receiving station cold energy recovery system, which is mainly used in the petrochemical, energy, storage and transportation, and green ammonia fields. It is used for heat exchange and gasification of cryogenic liquid hydrocarbons such as ethylene, ethane, propylene, and propane, as well as cryogenic liquid ammonia, with circulating water or chilled water. Background Technology
[0002] Currently, in the petrochemical, energy, storage and transportation, and green ammonia sectors, some companies are equipped with cryogenic liquefied hydrocarbon storage tanks for ethylene, ethane, propylene, propane, and other cryogenic liquefied hydrocarbons, or cryogenic liquid ammonia storage tanks. On one hand, cryogenic liquefied hydrocarbons or cryogenic liquid ammonia, after being pressurized by pumps and transported externally, generally require reheating with steam or hot water or vaporization to room temperature. On the other hand, shared circulating water needs to be cooled by cooling towers before circulation, and shared chilled water needs to be cooled by refrigeration units before circulation.
[0003] Taking the vaporization of liquid cryogenic ethylene through heat exchange with chilled water as an example, the heat exchange process data are as follows: the chilled water is a 50% ethylene glycol aqueous solution (antifreeze temperature -35℃), with an inlet temperature of 0℃ and an outlet temperature of -15℃; the liquid cryogenic ethylene has an inlet temperature of -99℃, and vaporization occurs through heat exchange. A commonly used shell-and-tube heat exchanger is selected, with the cryogenic ethylene flowing through the shell side and the chilled water flowing through the tube side.
[0004] Its disadvantages are as follows: When the chilled water flow rate deviates from the set value and gradually decreases, although the flow rate of liquid cryogenic ethylene is adjusted accordingly, the chilled water outlet temperature and the average temperature of the water in the heat exchange tubes will gradually decrease; when the chilled water flow rate is below a certain point, the chilled water in the end section of the heat exchange tubes will cool to -35°C or below and frost or ice will form on the inner surface of the heat exchange tubes. At this time, the ice inside the heat exchange tubes will block the water flow, and the area of chilled water freezing inside the heat exchange tubes will expand along the tubes; severe freezing may even cause the heat exchange tubes to burst. Therefore, a single shell-and-tube heat exchanger has insufficient operational flexibility, and the chilled water flow rate must have a safe lower limit; improper operation may lead to safety accidents.
[0005] In summary, when chilled water / circulating water and ethylene are directly exchanged using conventional shell-and-tube heat exchangers, the chilled water / circulating water inside the heat exchange tubes is highly susceptible to freezing and tube expansion due to cold. Therefore, using conventional shell-and-tube heat exchangers is not a feasible solution. Utility Model Content
[0006] The purpose of this invention is to overcome the above-mentioned deficiencies in the existing technology and provide a receiving station cold energy recovery system with a reasonable structural design. Without adding a third medium, it can exchange heat between low-temperature liquefied hydrocarbons or low-temperature liquid ammonia and circulating water or chilled water to recover cold energy, thereby achieving the purpose of reducing consumption and saving energy.
[0007] The technical solution adopted by this utility model to solve the above problems is: a receiving station cold energy recovery system, including a reboiler, a heater, and a cold source system; the reboiler includes a reboiler shell, a reboiler tube box, and a reboiler tube bundle; the reboiler tube bundle is fixedly installed inside the reboiler shell; the reboiler tube box is fixedly installed at one end of the reboiler shell, and the reboiler tube box is connected to the reboiler tube bundle; the heater includes a heater shell, a heater tube box, and a heater tube bundle; the heater tube bundle is fixedly installed inside the heater shell; the heater tube box is fixedly installed at one end of the heater shell, and the heater tube box is connected to the heater tube bundle; a liquid phase cold source medium inlet and a liquid phase cold source medium outlet are provided on the heater tube box; the heater is located above the reboiler, and the heater shell side and the reboiler shell side are connected; the cold source system is connected to the liquid phase cold source medium inlet through a pipeline; a liquid phase cold source medium inlet is provided on the reboiler shell, and the liquid phase cold source medium inlet is connected to the liquid phase cold source medium outlet through a pipeline, so that the reboiler shell side and the liquid phase cold source medium outlet are connected.
[0008] This invention features a heat source medium inlet and a heat source medium outlet on the reboiler tube box.
[0009] This invention features a heater tube outlet temperature gauge installed on the pipeline connecting the liquid phase cold source medium inlet and outlet, and a shut-off valve installed on the pipeline connecting the cold source system and the liquid phase cold source medium inlet. The heater tube outlet temperature gauge and the shut-off valve are interlocked.
[0010] This invention features a shell-side liquid level gauge on the reboiler shell and a heater inlet regulating valve on the pipeline connecting the cold source system to the inlet of the liquid phase cold source medium. The shell-side liquid level gauge and the heater inlet regulating valve are interlocked.
[0011] This invention provides a cold source medium reheating outlet on the heater housing, and a heater outlet valve on the cold source medium reheating outlet; a heater shell-side pressure gauge is provided on the heater housing, and the heater shell-side pressure gauge and the heater outlet valve are interlocked.
[0012] The cold source system of this utility model includes a cryogenic storage tank and a submersible pump. The submersible pump is installed inside the cryogenic storage tank and is connected to the inlet of the liquid phase cold source medium through a pipeline.
[0013] Compared with the prior art, this utility model utilizes the cold energy of low-temperature liquefied hydrocarbons or low-temperature liquid ammonia to cool circulating water or chilled water, and utilizes the heat energy of circulating water or chilled water to reheat liquefied hydrocarbons or ammonia. It has the following advantages and effects: 1. It eliminates the phenomenon of water freezing and its formation conditions; 2. It has high working flexibility, with the medium flow rate ranging from zero to the maximum rated value; 3. It is convenient to operate and maintain, and can be started and stopped quickly. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of an embodiment of the present utility model. Detailed Implementation
[0015] The present invention will be further described in detail below with reference to the accompanying drawings and through embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.
[0016] This utility model embodiment includes a reboiler 1, a heater 2, and a cold source system.
[0017] The reboiler 1 includes a reboiler shell 11, a reboiler tube box 12, and a reboiler tube bundle 13. The reboiler tube bundle 13 is fixedly installed inside the reboiler shell 11; the reboiler tube box 12 is fixedly installed at one end of the reboiler shell 11 and is connected to the reboiler tube bundle 13. A heat source medium inlet 15 and a heat source medium outlet 16 are provided on the reboiler tube box 12. A liquid phase cold source medium inlet 17 is provided at the lower or upper part of the reboiler shell 11. A reboiler shell-side level gauge 31 is provided on the reboiler shell 11. The tube side of the reboiler 1 is the heat source medium, and the shell side is the liquid phase cold source medium.
[0018] Heater 2 includes a heater housing 21, a heater tube box 22, and a heater tube bundle 23. The heater tube bundle 23 is fixedly disposed within the heater housing 21; the heater tube box 22 is fixedly disposed at one end of the heater housing 21 and connected to the heater tube bundle 23. A liquid-phase cold source medium inlet 25 and a liquid-phase cold source medium outlet 26 are provided on the heater tube box 22. The liquid-phase cold source medium inlet 17 is connected to the liquid-phase cold source medium outlet 26 via a pipeline, thus connecting the reboiler shell side to the liquid-phase cold source medium outlet 26. A heater tube side outlet temperature gauge 33 is provided on this pipeline. A cold source medium reheat outlet 27 is provided on the heater housing 21, and a heater outlet valve 36 is provided on the cold source medium reheat outlet 27. A heater shell side pressure gauge 32 is provided on the heater housing 21, and the heater shell side pressure gauge 32 is interlocked with the heater outlet valve 36. The heater outlet valve 36 is controlled according to the heater shell side pressure gauge 32 to maintain the system pressure-temperature balance. Heater 2 is located above reboiler 1. The shell side of the heater and the shell side of the reboiler are connected by connecting pipe 5. The refrigerant circulates between reboiling and condensation within the connected shell side of the reboiler and the shell side. The tube side of heater 2 is the liquid-phase cold source medium, and the shell side is the gas-phase cold source medium. The liquid-phase cold source medium in the shell side of the reboiler is led out through the tube side of heater 2 and then connected to the shell side of heater.
[0019] The cold source system is connected to the liquid cold source medium inlet 25 via a pipeline, on which a heater inlet regulating valve 34 and a shut-off valve 35 are installed. Further, the cold source system includes a cryogenic storage tank 3 and a submersible pump 4. The submersible pump 4 is located inside the cryogenic storage tank 3 and is connected to the liquid cold source medium inlet 25 via a pipeline. The heater tube-side outlet temperature gauge 33 is interlocked with the shut-off valve 35, and the reboiler shell-side level gauge 31 is interlocked with the heater inlet regulating valve 34. The opening of the heater inlet regulating valve 34 is controlled by the reboiler shell-side level gauge 31 to ensure that the liquid in the reboiler shell side is always maintained between submerging all reboiler tube bundles 13 and the full scale of the reboiler shell side, thus guaranteeing heat exchange efficiency. The shut-off valve 35 is controlled by the heater tube-side outlet temperature gauge 33 to cut off the cold flow when the temperature approaches the freezing point of the heat source, preventing freezing and blockage of the reboiler heat exchange tubes.
[0020] The heat source medium of this utility model includes circulating water, chilled water, etc. The chilled water is mainly ethylene glycol aqueous solution and chilled brine; the cold source medium includes liquefied hydrocarbons such as ethylene, ethane, propylene, propane, butene, and butane and their mixtures, as well as ammonia. The cold source medium is stored in the low temperature storage tank 3 of the cold source system and is pressurized by the submersible pump 4 and sent to the heater 2.
[0021] The working process of this utility model is as follows:
[0022] Taking the vaporization of liquid cryogenic ethylene through heat exchange with chilled water as an example, during operation, the cryogenic ethylene medium (~-102℃, 5~20 kPag) in the cryogenic storage tank 3 is pressurized to 2.5 MPag by the submersible pump 4 and then sent to the tube side of the heater 2 through pipeline. After heat exchange in the heater 2 (~-10℃, 2.45 MPa), it enters the shell side of the reboiler 1 through the liquid phase cryogenic medium outlet 26 and the liquid phase cryogenic medium inlet 17. The heater inlet regulating valve 34 is controlled according to the reboiler shell side level gauge 31. The interconnected space formed by the upper space of the reboiler shell side and the heater shell side space is filled with the evaporated gas of the cryogenic medium (-5℃, 24.5 barg). The heat source chilled water (~5℃, 0.5 MPa) flows through the reboiler tube side, and the liquid cryogenic ethylene flows through the heater tube side.
[0023] Chilled water enters the reboiler tube side through the heat source medium inlet 15. The reboiler tube bundle 13 heats the liquid ethylene (-5℃, 24.5 barg) in the reboiler shell side, thereby cooling the chilled water to (~0℃, 0.45 MPa). The chilled water absorbs the cold energy of the ethylene and cools down. The cooled chilled water flows out of the reboiler tube side through the heat source medium outlet 16. Inside the reboiler shell side, the liquid ethylene is heated and vaporized, reboiling into ethylene gas (-5℃, 24.5 barg), which rises to the heater shell side. The rising ethylene gas exchanges heat with the low-temperature liquid ethylene in the heater tube bundle 22. The heater outlet valve 36 is controlled by the heater shell side pressure gauge 32 to control the ethylene gas flow out of the heater 2.
[0024] Furthermore, it should be noted that the specific embodiments described in this specification may differ in the shape and name of their components. The above description is merely illustrative of the structure of this utility model. All equivalent or simple variations made based on the structure, features, and principles described in this utility model patent concept are included within the protection scope of this utility model patent.
Claims
1. A receiving station cold energy recovery system, comprising a reboiler, a heater, and a cold source system; the reboiler includes a reboiler shell, a reboiler tube box, and a reboiler tube bundle; the reboiler tube bundle is fixedly installed inside the reboiler shell; the reboiler tube box is fixedly installed at one end of the reboiler shell, and the reboiler tube box is connected to the reboiler tube bundle; the heater includes a heater shell, a heater tube box, and a heater tube bundle; the heater tube bundle is fixedly installed inside the heater shell; the heater tube box is fixedly installed at one end of the heater shell, and the heater tube box is connected to the heater tube bundle; a liquid phase cold source medium inlet and a liquid phase cold source medium outlet are provided on the heater tube box; the heater is located above the reboiler, and the heater shell side and the reboiler shell side are connected; characterized in that: The cold source system is connected to the liquid cold source medium inlet through a pipeline; a liquid cold source medium inlet is provided on the reboiler shell, and the liquid cold source medium inlet is connected to the liquid cold source medium outlet through a pipeline, so that the reboiler shell side is connected to the liquid cold source medium outlet.
2. The receiving station cold energy recovery system according to claim 1, characterized in that: The reboiler tube box is equipped with a heat source medium inlet and a heat source medium outlet.
3. The receiving station cold energy recovery system according to claim 1, characterized in that: A heater tube outlet temperature gauge is installed on the pipeline connecting the liquid phase cold source medium inlet and the liquid phase cold source medium outlet. A shut-off valve is installed on the pipeline connecting the cold source system and the liquid phase cold source medium inlet. The heater tube outlet temperature gauge and the shut-off valve are interlocked.
4. The receiving station cold energy recovery system according to claim 1, characterized in that: A reboiler shell-side level gauge is installed on the reboiler shell, and a heater inlet regulating valve is installed on the pipeline connecting the cold source system and the liquid phase cold source medium inlet. The reboiler shell-side level gauge and the heater inlet regulating valve are interlocked.
5. The receiving station cold energy recovery system according to claim 1, characterized in that: A reheat outlet for the cold source medium is provided on the heater shell, and a heater outlet valve is provided on the cold source medium reheat outlet; a heater shell-side pressure gauge is provided on the heater shell, and the heater shell-side pressure gauge is interlocked with the heater outlet valve.
6. The receiving station cold energy recovery system according to claim 1, characterized in that: The aforementioned cold source system includes a cryogenic storage tank and a submersible pump. The submersible pump is installed inside the cryogenic storage tank and is connected to the inlet of the liquid phase cold source medium through a pipeline.