Quenched water heat exchange system and method
By introducing a combination of flash valves, compressors, and multiple heat exchangers into the quench water system, and utilizing the heat exchange between butene and quench water, the problem of low-grade heat energy being difficult to recover is solved, achieving efficient energy utilization and cooling water conservation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-04-07
AI Technical Summary
Low-grade heat energy is difficult to utilize effectively when recovering waste heat from quench water, resulting in high cooling water consumption.
A heat exchange circuit consisting of a flash valve, a compressor, and multiple heat exchangers is used to exchange heat between butene and quench water. Low-grade heat energy is recovered and utilized through the compression and cooling of butene.
It achieves effective recovery of low-grade heat energy, reduces the amount of cooling water used, and improves energy utilization efficiency.
Smart Images
Figure CN121803879A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of quench water technology, and in particular, to a quench water heat exchange system and method. Background Technology
[0002] When recovering waste heat from quench water, high-grade heat energy can be recovered relatively well, while low-grade heat energy is directly discharged after being cooled by a large amount of cooling water. On the one hand, a lot of cooling water is consumed, and on the other hand, low-grade heat energy is difficult to be effectively recovered and utilized. Summary of the Invention
[0003] The embodiments of this application provide a quench water heat exchange system and method to solve the technical problem that low-grade heat energy is difficult to effectively recover and utilize when recovering waste heat from quench water.
[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.
[0005] According to a first aspect of this application, a quench water heat exchange system is provided, comprising a flash valve, a compressor, and a first recovery device, a second recovery device, and a third recovery device connected in sequence for circulating quench water. The first recovery device includes a first heat exchanger and a second heat exchanger arranged in parallel. The second recovery device includes at least one heat-using device that uses quench water as a heat source. The third recovery device includes a third heat exchanger. The first heat exchanger, the second heat exchanger, the third heat exchanger, the flash valve, and the compressor are connected in sequence to form a heat exchange loop for circulating butene. The butene is used to heat the quench water flowing through the first heat exchanger and the second heat exchanger and to cool the quench water flowing through the third heater.
[0006] In some embodiments of this application, based on the foregoing scheme, the system further includes a cooler, which is connected in parallel with the first heat exchanger.
[0007] In some embodiments of this application, based on the foregoing scheme, the first recovery device further includes at least two fourth heat exchangers, each of the third heat exchangers being connected in parallel with the first heat exchanger or the second heat exchanger, and the quench water of each of the fourth heat exchangers being heated by quench oil.
[0008] In some embodiments of this application, based on the foregoing scheme, at least one of the heat-using devices includes an air preheater, a propylene tower reboiler, and a light hydrocarbon feed heater.
[0009] In some embodiments of this application, based on the foregoing scheme, a superheater is provided between the compressor and the third heat exchanger.
[0010] According to a second aspect of this application, a quench water heat exchange method is provided, applied to a quench water heat exchange system described in any embodiment of the first aspect of this application, wherein the quench water flows sequentially through a first recovery device, a second recovery device, and a third recovery device, and the method includes: The quench water enters the first heat exchanger and the second heat exchanger, and is heated by butene, raising the temperature of the quench water from the first temperature to the second temperature. Cooling water enters at least one of the heat-using devices and is used as a heat source for at least one of the heat-using devices, the temperature of the cooling water dropping from the second temperature to the third temperature; The quench water enters the third heat exchanger and is cooled by butene, causing the temperature of the quench water to drop from the third temperature to the fourth temperature.
[0011] In some embodiments of this application, based on the foregoing scheme, the step of heating quench water with butene includes: butene being pressurized by the compressor, with its temperature rising from a fifth temperature to a sixth temperature and its pressure rising from a first pressure to a second pressure, wherein the sixth temperature is greater than the first temperature; butene entering the first heat exchanger from the compressor to heat the quench water, with its temperature decreasing from the sixth temperature to a seventh temperature, wherein the seventh temperature is greater than the first temperature; butene entering the second heat exchanger from the first heat exchanger to heat the quench water, with its temperature decreasing from the seventh temperature to an eighth temperature; the step of cooling quench water with butene includes: butene entering a flash valve from the second heat exchanger, becoming a gas-liquid mixture and its temperature decreasing from the eighth temperature to a ninth temperature; butene entering a third heat exchanger from the flash valve to cool the quench water, changing from a gas-liquid mixture to a gas and its pressure decreasing from the third pressure to a fourth pressure, wherein the ninth temperature is less than the third temperature.
[0012] In some embodiments of this application, based on the foregoing scheme, the first temperature is 82-83°C, the second temperature is 84-85°C, the first pressure is 3-4 bar, the second pressure is 17-18 bar, the third temperature is 61-62°C, the fourth temperature is 54-55°C, the fifth temperature is 49-50°C, the sixth temperature is 108-109°C, the seventh temperature is 98-99°C, the eighth temperature is 85-86°C, the ninth temperature is 44-45°C, the third pressure is 17-18 bar, and the fourth pressure is 5-6 bar.
[0013] In some embodiments of this application, based on the foregoing scheme, the system further includes a cooler, which is connected in parallel with the first heat exchanger, and the method further includes: If the compressor is in the start-up phase, the butene is cooled by the cooler instead of the first heat exchanger.
[0014] In some embodiments of this application, based on the foregoing scheme, a superheater is provided between the compressor and the third heat exchanger, and the method further includes: Butene enters the superheater from the third heat exchanger, and its temperature rises from the ninth temperature to the fifth temperature.
[0015] The beneficial effects of this application are as follows: Butene is cooled by quench water in the third heat exchanger. The butene absorbs the waste heat of the quench water and is vaporized, realizing the recovery of low-grade heat energy of the quench water. The butene carrying the waste heat of the quench water is pressurized by the compressor and then liquefied to heat the quench water in the first and second heat exchangers. Using butene as the heat exchange medium, the quench water in the first and second heat exchangers is heated by the quench water in the third heat exchanger. The heated quench water is then used in heat-using equipment, thus realizing the effective utilization of the low-grade heat energy of the quench water.
[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings: Figure 1 A simplified schematic diagram of a quench water heat exchange system according to an embodiment of this application is shown; Figure 2 A detailed schematic diagram of a quench water heat exchange system according to an embodiment of this application is shown; Figure 3 A schematic flowchart of a quench water heat exchange method according to an embodiment of this application is shown. Detailed Implementation
[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application.
[0019] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.
[0020] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.
[0021] The flowcharts shown in the accompanying drawings are merely illustrative and do not represent all required content, operations, or steps, nor do they necessarily need to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.
[0022] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.
[0023] Figure 1 A simplified schematic diagram of a quench water heat exchange system according to an embodiment of this application is shown. Figure 2 A detailed schematic diagram of a quench water heat exchange system according to an embodiment of this application is shown. Figure 1 In the diagram, butterfly symbols represent valves, circular symbols represent heat exchangers, square symbols represent preheaters, dashed box A corresponds to the first recovery unit, dashed box B corresponds to the second recovery unit, dashed box C corresponds to the third recovery unit, 1 is the first heat exchanger, 2 is the second heat exchanger, 3 is the propylene tower reboiler, 4 is the air preheater, 5 is the light hydrocarbon feed heater, 6 is the third heat exchanger, and 7 is the fourth heat exchanger. Figure 2 In the diagram, E-2055 is the first heat exchanger, E-2056 is the second heat exchanger, E-6004A is the propylene tower reboiler, the cracking furnace air preheater is an air preheater, E-1002 is the light hydrocarbon feed heater, E-2051 is the third heat exchanger, and E-2014 and E-2022 are the fourth heat exchangers. (See also...) Figure 1This application provides a quench water heat exchange system, including a flash valve, a compressor, and a first recovery device, a second recovery device, and a third recovery device connected in sequence for circulating quench water. The first recovery device includes a first heat exchanger and a second heat exchanger arranged in parallel. The second recovery device includes at least one heat-using device using quench water as a heat source. The third recovery device includes a third heat exchanger. The first heat exchanger, the second heat exchanger, the third heat exchanger, the flash valve, and the compressor are connected in sequence to form a heat exchange loop for circulating butene. The butene is used to heat the quench water flowing through the first and second heat exchangers and to cool the quench water flowing through the third heater. The butene can be butene-1.
[0024] In some embodiments, the system further includes a cooler connected in parallel with the first heat exchanger. The cooling medium of the cooler can be cooling water, and it can also be referred to as a start-up cooler. The parallel connection of the cooler with the first heat exchanger can be understood as one end of the cooler being connected to the compressor and the other end being connected to the second heat exchanger.
[0025] In some embodiments, the first recovery device further includes at least two fourth heat exchangers, each of the third heat exchangers being connected in parallel with the first heat exchanger or the second heat exchanger, and the quench water in each of the fourth heat exchangers being heated by quench oil.
[0026] In some embodiments, at least one of the heat-using devices includes an air preheater, a propylene tower reboiler, and a light hydrocarbon feed heater.
[0027] In some embodiments, a superheater is provided between the compressor and the third heat exchanger.
[0028] In some embodiments, an intake tank is provided between the superheater and the third heat exchanger, through which butene enters the intake tank from the third heat exchanger and then from the intake tank into the superheater.
[0029] It should be noted that if butene is in a saturated state before entering the compressor, the entire compression process is basically close to the medium dew point curve. There is a high probability that condensate will be generated in the pressure change areas such as the volute and flow channel inside the compressor, which poses a risk to the long-term operation of the unit. The superheater will heat the butene before it enters the compressor, which can effectively avoid the generation of condensate and improve the safety and reliability of the unit operation.
[0030] In some embodiments, a buffer tank is provided between the first heat exchanger and the second heat exchanger, through which butene enters the buffer tank from the first heat exchanger and then from the buffer tank into the second heat exchanger.
[0031] Thus, the compressor, the first heat exchanger, the buffer tank, the second heat exchanger, the flash valve, the third heat exchanger, the suction tank, and the superheater form a heat exchange loop for butene flow. Butene enters the first heat exchanger, the buffer tank, the second heat exchanger, the flash valve, the third heat exchanger, the suction tank, and the superheater sequentially from the compressor outlet, and then enters the compressor inlet.
[0032] In some embodiments, the first recovery device, the second recovery device, and the third recovery device all include bypass valves. When system fluctuations occur, supplementary adjustments are made via the bypass valves to ensure stable system operation.
[0033] In some embodiments, both the second and third recovery devices include at least one target heat exchanger, each of which is equipped with a backup steam heat source. This ensures system stability and effectively improves system stability during abnormal shutdowns of the heat exchange circuit, such as compressor shutdowns.
[0034] For example, the target heat exchanger is Figure 2 The series E3005, E-1001, E-1002, E-1003A, E-1005, E-1006, and E-1007 are listed.
[0035] In this application, butene is cooled by the quench water in the third heat exchanger to recover the low-grade heat energy of the quench water. The butene carrying the waste heat of the quench water is pressurized by the compressor and then used to heat the quench water in the first and second heat exchangers. Using butene as the heat exchange medium, the quench water in the first and second heat exchangers is heated by the quench water in the third heat exchanger. The heated quench water is then used in the heat-using equipment, thereby realizing the effective utilization of the low-grade heat energy of the quench water.
[0036] Figure 3 A schematic flowchart of a quench water heat exchange method according to an embodiment of this application is shown. See also: Figure 3 According to a second aspect of this application, a quench water heat exchange method is provided, applied to a quench water heat exchange system described in any embodiment of the first aspect of this application. The quench water flows sequentially through a first recovery device, a second recovery device, and a third recovery device. The method includes at least steps S1 to S3, detailed below: In step S1, quench water enters the first heat exchanger and the second heat exchanger, and is heated by butene, raising the temperature of the quench water from the first temperature to the second temperature.
[0037] In step S2, quench water enters at least one of the heating devices and is used as a heat source for at least one of the heating devices, and the temperature of the quench water drops from the second temperature to the third temperature.
[0038] In step S3, quench water enters the third heat exchanger and is cooled by butene, causing the temperature of the quench water to drop from the third temperature to the fourth temperature.
[0039] In some embodiments, the heating of quench water by butene includes: butene being pressurized by the compressor, with its temperature rising from a fifth temperature to a sixth temperature and its pressure rising from a first pressure to a second pressure, wherein the sixth temperature is greater than the first temperature; butene entering the first heat exchanger from the compressor to heat the quench water, with its temperature decreasing from the sixth temperature to a seventh temperature, wherein the seventh temperature is greater than the first temperature; and butene entering the second heat exchanger from the first heat exchanger to heat the quench water, with its temperature decreasing from the seventh temperature to an eighth temperature. The cooling of quench water by butene includes: butene entering a flash valve from the second heat exchanger, becoming a gas-liquid mixture and its temperature decreasing from the eighth temperature to a ninth temperature; and butene entering a third heat exchanger from the flash valve to cool the quench water, changing it from a gas-liquid mixture to a gas and its pressure decreasing from a third pressure to a fourth pressure, wherein the ninth temperature is less than the third temperature.
[0040] In some embodiments, the first temperature is 82-83°C, the second temperature is 84-85°C, the first pressure is 3-4 bar, the second pressure is 17-18 bar, the third temperature is 61-62°C, the fourth temperature is 54-55°C, the fifth temperature is 49-50°C, the sixth temperature is 108-109°C, the seventh temperature is 98-99°C, the eighth temperature is 85-86°C, the ninth temperature is 44-45°C, the third pressure is 17-18 bar, and the fourth pressure is 5-6 bar. In some embodiments, the first temperature is 82.2°C, the second temperature is 84.3°C, the first pressure is 3.8 bar, the second pressure is 17.6 bar, the third temperature is 61.8°C, the fourth temperature is 54°C, the fifth temperature is 49°C, the sixth temperature is 108°C, the seventh temperature is 98°C, the eighth temperature is 85°C, the ninth temperature is 44°C, the third pressure is 17.4 bar, and the fourth pressure is 5.2 bar.
[0041] In some embodiments, the system further includes a cooler connected in parallel with the first heat exchanger, and the method further includes: if the compressor is in the start-up phase, cooling the butene by replacing the first heat exchanger with the cooler.
[0042] In some embodiments, a superheater is provided between the compressor and the third heat exchanger, and the method further includes: butene entering the superheater from the third heat exchanger, with the temperature rising from the ninth temperature to the fifth temperature.
[0043] In this way, after being pressurized by the compressor, butene enters the first heat exchanger, changing from a gas to a liquid. This heats the quench water in the first heat exchanger, causing the temperature of the quench water to rise and the butene's own temperature to drop for the first time. After passing through the buffer tank, it enters the second heat exchanger, where it heats the quench water, causing the temperature of the quench water in the second heat exchanger to rise and the butene's own temperature to drop for the second time. After passing through the flash valve to reduce pressure, it becomes a gas-liquid mixture and then enters the third heat exchanger, where it cools the quench water and becomes a gas. It then enters the suction tank, passes through the superheater, and re-enters the compressor, thus completing the butene cycle. During the butene cycle, the low-temperature quench water is recovered to heat the high-temperature quench water, achieving the purpose of energy-efficient utilization and reducing cooling water consumption.
[0044] It should be noted that the quench water flowing through the first and second heat exchangers is high-temperature cooling water, while the quench water flowing through the third heat exchanger is low-temperature quench water.
[0045] In actual use, this application can save 10 kg of standard oil and 16,000 tons of cooling water per year.
[0046] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A quench water heat exchange system, characterized in that, The device includes a flash valve, a compressor, and a first recovery device, a second recovery device, and a third recovery device connected in sequence for circulating quench water. The first recovery device includes a first heat exchanger and a second heat exchanger arranged in parallel. The second recovery device includes at least one heat-using device that uses quench water as a heat source. The third recovery device includes a third heat exchanger. The first heat exchanger, the second heat exchanger, the third heat exchanger, the flash valve, and the compressor are connected in sequence to form a heat exchange circuit for circulating butene. The butene is used to heat the quench water flowing through the first heat exchanger and the second heat exchanger and to cool the quench water flowing through the third heater.
2. The quench water heat exchange system according to claim 1, characterized in that, The system also includes a cooler, which is connected in parallel with the first heat exchanger.
3. The quench water heat exchange system according to claim 1, characterized in that, The first recovery device further includes at least two fourth heat exchangers, each of the third heat exchangers being connected in parallel with the first heat exchanger or the second heat exchanger, and the quench water in each of the fourth heat exchangers being heated by quench oil.
4. The quench water heat exchange system according to claim 1, characterized in that, At least one of the heat-using devices includes an air preheater, a propylene tower reboiler, and a light hydrocarbon feed heater.
5. A quench water heat exchange system according to claim 1, characterized in that, A superheater is provided between the compressor and the third heat exchanger.
6. A method for quenching water heat exchange, applied to a quenching water heat exchange system according to any one of claims 1-5, wherein the quenching water flows sequentially through a first recovery device, a second recovery device, and a third recovery device, characterized in that, The method includes: The quench water enters the first heat exchanger and the second heat exchanger, and is heated by butene, raising the temperature of the quench water from the first temperature to the second temperature. Cooling water enters at least one of the heat-using devices and is used as a heat source for at least one of the heat-using devices, the temperature of the cooling water dropping from the second temperature to the third temperature; The quench water enters the third heat exchanger and is cooled by butene, causing the temperature of the quench water to drop from the third temperature to the fourth temperature.
7. A method for quenching water heat exchange according to claim 6, characterized in that, The heating of quench water with butene includes: butene being pressurized by the compressor, with its temperature rising from a fifth temperature to a sixth temperature and its pressure rising from a first pressure to a second pressure, wherein the sixth temperature is greater than the first temperature; butene entering the first heat exchanger from the compressor to heat the quench water, with its temperature decreasing from the sixth temperature to a seventh temperature, wherein the seventh temperature is greater than the first temperature; butene entering the second heat exchanger from the first heat exchanger to heat the quench water, with its temperature decreasing from the seventh temperature to an eighth temperature; the cooling of quench water with butene includes: butene entering a flash valve from the second heat exchanger, becoming a gas-liquid mixture and its temperature decreasing from the eighth temperature to a ninth temperature; butene entering a third heat exchanger from the flash valve to cool the quench water, changing it from a gas-liquid mixture to a gas and its pressure decreasing from the third pressure to a fourth pressure, wherein the ninth temperature is less than the third temperature.
8. A method for quenching water heat exchange according to claim 7, characterized in that, The first temperature is 80-84℃, the second temperature is 85-90℃, the first pressure is 3-4 bar, the second pressure is 17-18 bar, the third temperature is 60-65℃, the fourth temperature is 51-55℃, the fifth temperature is 45-50℃, the sixth temperature is 100-110℃, the seventh temperature is 95-99℃, the eighth temperature is 80-86℃, the ninth temperature is 40-45℃, the third pressure is 17-18 bar, and the fourth pressure is 5-6 bar.
9. A method for quenching water heat exchange according to claim 6, characterized in that, The system further includes a cooler connected in parallel with the first heat exchanger, and the method further includes: If the compressor is in the start-up phase, the butene is cooled by the cooler instead of the first heat exchanger.
10. A method for quenching water heat exchange according to claim 7, characterized in that, A superheater is provided between the compressor and the third heat exchanger, and the method further includes: Butene enters the superheater from the third heat exchanger, and its temperature rises from the ninth temperature to the fifth temperature.