Heat pump rectification system and method
By converting low-grade heat energy into high-grade heat energy through a heat pump distillation system, the problems of high energy consumption and environmental pollution of traditional distillation systems are solved, achieving efficient energy recycling and significant cost reduction.
Patent Information
- Application Number
- CN202511542910.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-27
- Publication Date
- 2026-01-02
AI Technical Summary
Traditional distillation systems rely on external steam as a heat source, resulting in high energy consumption and high operating costs. Furthermore, the low-temperature heat at the top of the column is not effectively utilized, leading to energy waste and environmental pollution.
The heat pump distillation system, consisting of a storage and transportation module, an evaporation module, a heat boosting module, and a reboiling module, forms a closed-loop circulation system that converts low-grade heat energy into high-grade heat energy, reducing dependence on external heat sources and achieving efficient recycling of heat.
It significantly reduces energy consumption and operating costs, improves the system's energy self-sufficiency and operational stability, and reduces carbon emissions, thus providing energy-saving, economic, and environmental benefits.
Smart Images
Figure CN121243801A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of rectification, in particular to a heat pump rectification system and method. BACKGROUND
[0002] Rectification is a separation process that separates each component in a mixture according to the different volatility of each component. As the core separation unit of petroleum and chemical production process, the energy consumption of rectification process is mainly concentrated in the heating of tower kettle material and the cooling of tower top material. The traditional rectification system usually uses external steam as the heat source of tower kettle, and needs to remove the low-temperature heat of tower top from the system through cooling medium such as circulating water. The system always relies on the continuous supply of external steam, resulting in high energy consumption and operation cost.
[0003] Therefore, there is an urgent need for a heat pump rectification system and method that can reduce the dependence on external energy. SUMMARY
[0004] The present application provides a heat pump rectification system and method to reduce the dependence on external energy and save operation cost.
[0005] In order to achieve the above purpose, according to the first aspect of the present application, a heat pump rectification system is provided, comprising: a rectification module; a storage and delivery module for storing and delivering working medium; an evaporation module, the inlet of which is connected with the outlet of the storage and delivery module; a thermal lifting module, the inlet of which is connected with the outlet of the evaporation module; a reboiling module for providing heat source for the rectification module, the reboiling module comprising a working medium reboiler; the inlet of the working medium reboiler is connected with the outlet of the thermal lifting module, and the outlet of the working medium reboiler is connected with the inlet of the storage and delivery module.
[0006] In some embodiments, the reboiling module further comprises a steam reboiler, the inlet of which is connected with an external steam storage device.
[0007] In some embodiments, the rectification module comprises rectification columns arranged in parallel, and each rectification column is in heat exchange connection with at least one steam reboiler and at least one working medium reboiler.
[0008] In some embodiments, the evaporation module comprises evaporators arranged in parallel, and at least part of the evaporators are in heat exchange connection with the rectification module.
[0009] In some embodiments, the rectification column is provided with a raw material inlet, a tower top steam outlet and a reflux port. A reflux tank is arranged on a pipeline between the overhead vapor outlet and the reflux inlet; The evaporator is arranged between the overhead vapor outlet and the reflux tank and is in heat exchange connection with the rectifying column.
[0010] In some embodiments, the storage and delivery module comprises a storage device and a delivery pump; an inlet of the storage device is connected with an outlet of the reboiling module, and the storage device is provided with a cooling mechanism; an inlet of the delivery pump is connected with the storage device, and an outlet of the delivery pump is connected with the evaporation module.
[0011] In some embodiments, the thermal lifting module comprises a heat pump arranged in parallel, and a compressor of the heat pump comprises one of a screw compressor, a centrifugal compressor, a Roots compressor and a reciprocating compressor.
[0012] According to a second aspect of the present application, a heat pump rectification method is provided, which uses the heat pump rectification system provided in the first aspect of the present application, and the heat pump rectification method comprises: The working medium in the liquid phase is sent to the evaporation module for evaporation to form the first working medium in the gas phase; The first working medium is sent to the thermal lifting module for temperature lifting and pressure lifting to form the second working medium; The second working medium is sent to the working medium reboiler and exchanges heat with the column still liquid in the rectifying module to form the third working medium in the liquid phase; The third working medium is sent to the storage and delivery module; The above steps are repeated until the rectification process is completed.
[0013] In some embodiments, the rectification process comprises an initial stage and a stable operation stage; In the initial stage, external steam is introduced into the steam reboiler, and the steam reboiler and the working medium reboiler jointly provide a heat source for the rectification process; In the stable operation stage, the working medium reboiler independently provides a heat source for the rectification process.
[0014] In some embodiments, the heat pump rectification method satisfies at least one of the following conditions: (a) The outlet pressure of the heat pump is 0.3 MPaG to 1.0 MPaG; (b) The outlet gas temperature of the heat pump is 77°C to 85°C.
[0015] In some embodiments, the evaporation pressure of the working medium in the evaporator is in a positive pressure or negative pressure state; or, The evaporation pressure of the working medium in the evaporator is 0.01 MPaG to 0.05 MPaG.
[0016] In some embodiments, the working medium comprises one of a carbon five component, a refrigerant; The refrigerant comprises at least one of R245fa, R134a, and R143a.
[0017] In some embodiments, the rectification raw material input into the rectification module comprises a carbon five component, and the rectification temperature of the rectification module is 45-80°C.
[0018] The heat pump rectification system provided by the embodiments of the present application comprises a storage and conveying module, an evaporation module, a heat lifting module, and a reboiling module, which together form a closed circulation system. The circulation system can convert low-grade heat energy into high-grade heat energy and recycle it, thereby reducing the dependence on external one-off heat sources in the rectification process, reducing energy consumption and operating costs, and improving the energy self-sufficiency rate and operating stability of the system.
[0019] The heat pump rectification method provided by the embodiments of the present application adopts the heat pump rectification system described above, and therefore has all the beneficial effects of the heat pump rectification system.
[0020] The technical effects of the method of the present application using a heat pump rectification system are not repeated. Other features and advantages of the present application will be described in detail in the subsequent specific embodiments. BRIEF DESCRIPTION OF DRAWINGS
[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0022] In order to more completely understand the present application and its beneficial effects, the following will be described in conjunction with the drawings, wherein the same reference numerals in the following description represent the same parts.
[0023] Figure 1 is a schematic diagram of one embodiment of the heat pump rectification system provided in the exemplary embodiments of the present disclosure; Figure 2 is a schematic diagram of the rectification system used in Comparative Example 1 of the present disclosure.
[0024] Explanation of reference numerals: 10, rectification module; 11, rectification column; 20, storage and conveying module; 21, storage device; 22, conveying pump; 30, evaporation module; 31, evaporator; 40, heat lifting module; 41, heat pump; 50, reboil module; 51, working fluid reboiler; 52, steam reboiler. DETAILED DESCRIPTION
[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative work fall within the scope of protection of the present application.
[0026] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In addition, although the terms first, second, etc. can be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the present application. As used herein, the term "and / or" includes any one and all combinations of the associated listed items.
[0027] In the description of the present application, the meaning of "a plurality of" is two or more, at least one of which can be one, two or more, unless otherwise explicitly specified and limited.
[0028] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.
[0029] Traditional rectification systems usually use external steam as the heat source of the tower kettle, and at the same time, the low-temperature heat at the top of the tower needs to be removed from the system through a cooling medium such as circulating water. This energy utilization mode leads to two outstanding problems: on the one hand, a large amount of low-grade heat energy at the top of the tower is not effectively utilized and is directly discharged, causing energy waste; on the other hand, the system always relies on the continuous supply of external steam, resulting in high energy consumption and operating costs; in addition, the process simultaneously produces a large amount of indirect carbon emissions caused by steam consumption, as well as a large amount of heat pollution caused by the circulating water system, which has a double negative impact on the environment.
[0030] According to a first aspect of the present application, referring to Figure 1 , a heat pump rectification system is provided, comprising a rectification module 10, a storage and delivery module 20, an evaporation module 30, a thermal lifting module 40 and a reboiling module 50.
[0031] The rectification module 10 is used for rectification treatment of the tower kettle liquid; the storage and delivery module 20 is used for storing and delivering the working medium; the evaporation module 30 is used for evaporating the working medium, and the inlet of the evaporation module 30 is connected with the outlet of the storage and delivery module 20; the thermal lifting module 40 is used for temperature lifting and pressure boosting of the working medium, and the inlet of the thermal lifting module 40 is connected with the outlet of the evaporation module 30; the reboiling module 50 is used for providing a heat source for the rectification module 10, and the reboiling module 50 comprises a working medium reboiler 51; the working medium reboiler 51 is in heat exchange connection with the rectification module 10, so that the working medium exchanges heat with the tower kettle liquid in the rectification module 10; the inlet of the working medium reboiler 51 is connected with the outlet of the thermal lifting module 40, and the outlet of the working medium reboiler 51 is connected with the inlet of the storage and delivery module 20.
[0032] The working medium is output from the storage and delivery module 20, sequentially flows through the evaporation module 30 and the thermal lifting module 40 for treatment, and then enters the reboiling module 50 in a high-temperature and high-pressure gaseous phase as a heat source to exchange heat with the tower kettle liquid in the rectification module 10. After heat exchange, the working medium condenses into a liquid phase and flows back to the storage and delivery module 20, thereby providing the required heat for the rectification process through the phase change cycle of the working medium.
[0033] It can be understood that the structures of the heat pump rectification system are connected through pipelines, and control valves can be selectively arranged on the pipelines to adjust the on-off and / or working medium flow of the pipelines. The heat exchange connection refers to a connection mode for realizing energy transfer through heat exchange. Exemplarily, the heat exchange connection mode in the present embodiment adopts a partition wall type heat exchanger.
[0034] The storage delivery module 20, the evaporation module 30, the thermal lifting module 40 and the reboiling module 50 jointly constitute a closed-loop circulation system, which can convert low-grade heat energy into high-grade heat energy and recycle it, thereby reducing the dependence of the rectification process on external one-off heat sources (such as steam), reducing energy consumption and operating costs, and improving the energy self-sufficiency rate and operating stability of the system.
[0035] In some embodiments, the rectification module 10 comprises a rectification tower 11 provided with a raw material inlet, a tower top vapor outlet and a reflux inlet; the rectification raw material enters the rectification tower 11 through the raw material inlet, the tower kettle liquid is derived from the rectification raw material entering the rectification tower 11, and the vapor generated in the rectification process is discharged through the tower top vapor outlet. For the sake of description, the vapor generated in the rectification process discharged from the tower top vapor outlet is defined as the tower top vapor.
[0036] In some embodiments, the evaporation module 30 comprises an evaporator 31, which is in heat exchange connection with the rectification tower 11 to realize heat exchange between the working medium and the tower top vapor. The tower top vapor is condensed and releases heat in the heat exchange process with the evaporator 31, forming a condensate, and the heat released by the condensate is used to evaporate the liquid-phase working medium flowing through the evaporator 31, forming a gas-phase working medium, thereby realizing the recovery of the tower top waste heat.
[0037] In this embodiment, the evaporator 31 recovers the tower top waste heat of the rectification tower 11 and uses it to heat the rectification tower 11 after improving its quality, realizing efficient recycling of heat within the system, greatly reducing the dependence on external steam and circulating water consumption, significantly reducing energy consumption and operating costs, while effectively reducing carbon emissions, having significant energy-saving, economic and environmental benefits.
[0038] A reflux tank is arranged on the pipeline between the tower top vapor outlet and the reflux inlet, and the evaporator 31 is located between the reflux tank and the tower top vapor outlet. The inlet of the reflux tank is in communication with the tower top vapor outlet, and the outlet of the reflux tank is in communication with the reflux inlet of the rectification tower 11. At least part of the condensate formed by the heat exchange and condensation of the tower top vapor and the evaporator 31 flows to the rectification tower 11 through the reflux inlet.
[0039] Specifically, the condensate comprises a first part and a second part, the first part is collected as a rectification product (not shown in the figure), and the second part is refluxed into the rectification tower 11 and collected into the tower kettle liquid.
[0040] In some embodiments, the thermal lifting module 40 comprises a heat pump 41; the inlet of the heat pump 41 is in communication with the outlet of the evaporator 31, and the heat pump 41 is in heat exchange connection with the rectification tower 11.
[0041] In some embodiments, the reboiling module 50 further includes a steam reboiler 52. The inlet of the steam reboiler 52 is connected to an external steam storage device (not shown in the figure). The steam reboiler 52 is heat-exchange connected to the distillation column 11 to realize heat exchange between the working medium and the bottom liquid in the distillation column 11. The steam reboiler 52 provides supplementary heat to the distillation column 11. That is, when the heat provided by the working medium reboiler 51 is less than the heat required for the distillation process, external steam is introduced into the steam reboiler 52 as a supplementary heat source to exchange heat with the bottom liquid in the distillation column 11.
[0042] The steam flow rate of the reboiler 52 can be manually controlled or automatically regulated by a control system.
[0043] For example, the control system includes a temperature sensor installed inside the distillation column 11, a regulating valve installed on the steam pipeline outside the steam reboiler 52, and a temperature controller that is signal-connected to the temperature sensor and the regulating valve respectively. The temperature controller is configured to receive the temperature signal inside the distillation column 11 detected by the temperature sensor, compare it with a preset temperature value, and output a control signal to the regulating valve according to the comparison result to automatically adjust the steam flow rate so that the temperature inside the distillation column 11 is stabilized within a preset range.
[0044] In some embodiments, the storage and delivery module 20 includes a storage device 21 and a delivery pump 22; the inlet of the storage device 21 is connected to the outlet of the reboiling module 50; the storage device 21 is equipped with a cooling mechanism for cooling the high-temperature, high-pressure liquid working medium output from the reboiling module 50 to a temperature suitable for return to the evaporator 31 for re-evaporation. The cooling mechanism achieves the cooling by at least one of pressure-reducing flash evaporation or heat exchange with other low-temperature media.
[0045] For example, the storage device 21 employs a flash tank. The high-temperature, high-pressure liquid working medium output from the reboiling module 50 enters the storage device 21 and undergoes flash evaporation at a lower pressure. Part of the working medium absorbs its own sensible heat and evaporates into a gaseous phase, thereby significantly reducing the temperature of the remaining liquid working medium and achieving efficient cooling. The gaseous working medium generated by flash evaporation is treated by at least one of the following methods: condensation using circulating water, preheating the raw materials, or returning it to the inlet of the heat pump 41 for recompression; preferably, the gaseous working medium generated by flash evaporation is returned to the inlet of the heat pump 41 for recompression.
[0046] The inlet of the transfer pump 22 is connected to the storage device 21, and the outlet of the transfer pump 22 is connected to the evaporation module 30. The transfer pump 22 provides power for the circulation of the entire working medium, ensuring the stable establishment and continuous operation of the circulation.
[0047] The transfer pump 22 includes one of a centrifugal pump, a screw pump, and a canned motor pump. For example, the transfer pump 22 is a centrifugal pump.
[0048] In some embodiments, the distillation column 11 is independently configured with at least one steam reboiler 52, at least one working fluid reboiler 51, and at least one evaporator 31 to form independent and flexibly adjustable heat circulation units. It is understood that the number of evaporators 31 can be greater than or equal to the number of distillation columns 11. When the number of evaporators 31 is greater than the number of distillation columns 11, some evaporators 31 may not exchange heat with the distillation column 11, and external energy may be used to evaporate the working medium.
[0049] The number of distillation column 11, steam reboiler 52, working fluid reboiler 51, evaporator 31 and heat pump 41 can be configured according to process requirements; when multiple distillation columns 11 are set, they are arranged in parallel.
[0050] In some examples, the distillation module 10 includes a distillation column 11, and the distillation column 11 is configured with a steam reboiler 52, a working fluid reboiler 51, and an evaporator 31.
[0051] In some examples, see Figure 1 The distillation module 10 includes four distillation columns 11 connected in parallel, each of which is equipped with a steam reboiler 52 and a working fluid reboiler 51. The evaporation module 30 includes five evaporators 31 connected in parallel, four of which are connected to the four distillation columns 11 to recover waste heat from the top of the columns, and the fifth evaporator 31 is configured to evaporate the working medium through an external heat source (not shown in the figure). The heat boosting module 40 includes three heat pumps 41 connected in parallel. The gaseous working medium generated by all the evaporators 31 is collected and distributed to the three heat pumps 41 for compression. The compressed high-temperature and high-pressure gaseous working medium is then distributed to the four working fluid reboilers 51 to provide a heat source for each distillation column 11.
[0052] In some embodiments, the evaporator 31 includes one of a shell-and-tube heat exchanger and a plate heat exchanger. Exemplarily, the evaporator 31 employs a kettle-type heat exchanger within the shell-and-tube heat exchanger category.
[0053] In some embodiments, the compressor of heat pump 41 includes one of a screw compressor, a centrifugal compressor, a Roots compressor, and a reciprocating compressor. For example, the compressor of heat pump 41 is a twin-screw compressor.
[0054] In some embodiments, the working fluid reboiler 51 includes a shell-and-tube heat exchanger and a plate heat exchanger. Exemplarily, the working fluid reboiler 51 employs a thermosiphon heat exchanger within a shell-and-tube heat exchanger.
[0055] In some embodiments, the flash tank includes a horizontal flash tank and a vertical flash tank. Exemplarily, the flash tank is a vertical flash tank.
[0056] In a second aspect, embodiments of this application provide a heat pump distillation method, employing the heat pump distillation system provided in the first aspect of this application. The heat pump distillation method includes: The working medium in the liquid phase is sent to the evaporation module 30 for evaporation to form the first working medium in the gas phase. The first working medium is sent to the heat boosting module 40 for temperature and pressure increase to form the second working medium; The second working medium is sent to the working medium reboiler 51 and exchanges heat with the bottom liquid in the distillation module 10 to form a third working medium in the liquid phase. The third working medium is sent to the storage and delivery module 20; Repeat the above steps until the distillation process is complete.
[0057] In some embodiments, the distillation process includes an initial phase and a stable operation phase; In the initial stage, external steam is introduced into the steam reboiler 52, and the steam reboiler 52 and the working medium reboiler 51 together provide a heat source for the distillation process. During the stable operation phase, the working fluid reboiler 51 independently provides a heat source for the distillation process.
[0058] Understandably, in the initial stage, external steam is introduced into the steam reboiler 52. At this time, the heating capacity of the working fluid reboiler 51 has not yet been fully established, and the steam reboiler 52 and the working fluid reboiler 51 jointly provide the heat source for the distillation process. As the system operates, the heating capacity of the working fluid reboiler 51 gradually increases, and the external steam supply to the steam reboiler 52 is reduced accordingly. In the stable operation stage, the working fluid reboiler 51 achieves stable heating, and the introduction of external steam into the steam reboiler 52 is completely stopped. The working fluid reboiler 51 independently provides the required heat source for the distillation process.
[0059] In some embodiments, the working medium comprises one of the C5 fraction and a refrigerant. The C5 fraction is a byproduct of the ethylene production process from petroleum cracking, and consists of a mixture of hydrocarbons containing five carbon atoms, mainly including isoprene, cyclopentadiene, and isoprene.
[0060] Specifically, the refrigerant includes at least one of R245fa, R134a, and R143a.
[0061] In some embodiments, the mass flow rate of the working medium is 220~250 t / h.
[0062] Specifically, the mass flow rate of the working medium is any one or any two of the following values: 220 t / h, 225 t / h, 230 t / h, 235 t / h, 240 t / h, 245 t / h, and 250 t / h.
[0063] In some embodiments, the operating pressure of the flash tank is set to 0.01 MPaG to 0.05 MPaG.
[0064] Specifically, the working pressure of the flash tank is set to a range of any one or any two of 0.01 MPaG, 0.02 MPaG, 0.03 MPaG, 0.04 MPaG, and 0.05 MPaG.
[0065] In some embodiments, the operating pressure of the transfer pump 22 is 0.3 MPaG ~ 0.4 MPaG, providing circulating power for the working medium.
[0066] Specifically, the operating pressure of the delivery pump 22 is any one or any two of the following: 0.30 MPaG, 0.31 MPaG, 0.32 MPaG, 0.33 MPaG, 0.34 MPaG, 0.35 MPaG, 0.36 MPaG, 0.37 MPaG, 0.38 MPaG, 0.39 MPaG, and 0.40 MPaG.
[0067] In some embodiments, the evaporation pressure of the working medium inside the evaporator 31 is either positive or negative.
[0068] Optionally, the evaporation pressure of the working medium in the evaporator 31 is 0.01 MPaG~0.05 MPaG.
[0069] Specifically, the evaporation pressure of the working medium in the evaporator 31 is within the range of any one or any two of 0.01 MPaG, 0.02 MPaG, 0.03 MPaG, 0.04 MPaG, and 0.05 MPaG.
[0070] When the evaporation pressure of the working medium in the evaporator 31 is 0.01 MPaG~0.05 MPaG, the working medium can boil and evaporate at a lower temperature, thereby efficiently recovering and utilizing the low-temperature waste heat of the top steam of the distillation column 11, and thus improving the utilization efficiency of the top steam.
[0071] In some embodiments, the outlet pressure of the heat pump 41 is 0.3 MPaG to 1.0 MPaG.
[0072] Specifically, the outlet pressure of heat pump 41 is within the range of any one or any two of 0.3 MPaG, 0.4 MPaG, 0.5 MPaG, 0.6 MPaG, 0.7 MPaG, 0.8 MPaG, 0.9 MPaG, and 1.0 MPaG.
[0073] For example, the outlet pressure of heat pump 41 is 0.4 MPaG to 0.6 MPaG.
[0074] When the outlet pressure of heat pump 41 is 0.3 MPaG to 1.0 MPaG, the temperature of the compressed working medium can effectively cover the heating temperature range required by the bottom of the tower, ensuring that there is a sufficient and reasonable heat transfer temperature difference between the working medium reboiler 51 and the bottom liquid, thus meeting the optimal balance between the system's heating demand and operating energy consumption.
[0075] In some embodiments, the outlet gas temperature of the heat pump 41 is 77°C to 85°C. This outlet gas temperature range ensures a sufficient heat transfer temperature difference between the heat pump 41 and the liquid in the bottom of the distillation column 11, thereby meeting the heat exchange requirements of the reboiler.
[0076] Specifically, the outlet gas temperature of heat pump 41 is any one or any two of the following values: 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, and 85°C.
[0077] In some embodiments, the distillation feedstock introduced into the distillation module 10 contains C5 components, and the distillation temperature of the distillation module 10 is 45~80°C.
[0078] In some embodiments, the heat pump 41 is equipped with a sealing system for isolating the compressed working medium from the external environment. The sealing system employs a series dry gas seal, using the high-temperature, high-pressure gaseous working medium at the outlet of the heat pump 41 as the pre-sealing gas and nitrogen as the main sealing gas; the leaked mixture of the pre-sealing gas and the main sealing gas discharged from the sealing system is condensed and recovered by a cooler, and the working medium contained therein is recovered.
[0079] Example 1 System settings: The distillation module contains four distillation columns (T1-T4) connected in parallel. The process design parameters of each column are shown in Table 1. The process design parameters are the target operating parameters that the distillation module needs to achieve. The design of the subsequent heat pump distillation system is based on these parameters. Table 1. Process design parameters for distillation columns
[0080] The storage device of the storage and conveying module is a condensate flash tank, and the conveying pump is a condensate pump; The evaporation module includes four evaporators connected in parallel, with each evaporator corresponding to a distillation column. The heat enhancement module includes three heat pump compressors connected in parallel; The reboiling module includes four sets of working fluid reboilers and steam reboilers. Each distillation column is equipped with one working fluid reboiler and one steam reboiler. During the initial stage, the mass flow rate of the working medium is set to 220~250t / h. After the condensate pump is pressurized, it is delivered to each evaporator. The working pressure of the condensate pump is set to 0.3~0.4MPaG. The evaporation pressure of the working medium in evaporator 31 is set to 0.01~0.05MPaG. The working medium absorbs the residual heat at the top of the tower and evaporates in the evaporator to form the first working medium. The outlet operating pressure of the heat pump is set to 0.4~0.6MPaG, and the corresponding outlet temperature of the working medium is 77~85℃. After the first working medium is pressurized and heated to 0.4~0.6MPaG and 77~85℃ by the heat pump, it becomes the second working medium. The second working medium is fed into each working medium reboiler and condenses to release heat, providing a reboiling heat source for the distillation column. After condensation, it forms the third working medium. The third working medium enters the flash tank, and the working pressure of the flash tank is set to 0.01~0.05MPaG. The gas phase generated by flashing returns to the heat pump inlet, and the liquid working medium is transported to the evaporator by the condensate pump to complete the cycle. Meanwhile, external steam is introduced into the reboiler tower. The external steam condenses and releases heat to provide a supplementary reboiler heat source for the distillation tower. The temperature of the external steam is 165~175℃, and the flow rate is automatically controlled between 0~25.3t / h. During the stable operation phase, the external steam supply is stopped, and the reboiler provides all the heat for distillation.
[0081] With C5 components as the distillation feedstock and an annual processing capacity of 300,000 tons, the consumption of the system in Example 1 from the stable operation phase to the end of operation is shown in Table 2.
[0082] Comparative Example 1 like Figure 2As shown, compared with Example 1, the distillation system used in Comparative Example 1 did not have a storage and transportation module, an evaporation module, or a heat boosting module. All four distillation columns were provided with heat by a steam reboiler, and the process design parameters of the four distillation columns were the same as those in Example 1. External steam was used to heat the distillation columns through the steam reboiler. The mass flow rate of the steam was set to 25.3 t / h, the temperature was 165~175℃, and the pressure was 0.5~0.6 MPaG. Distillation was carried out using C5 components as raw materials. When the annual processing capacity was 300,000 tons, the system operated for 8,000 hours. From the time Example 1 entered the stable operation stage, the consumption of Comparative Example 1 within the same operating cycle was recorded simultaneously. The consumption of each component is shown in Table 2.
[0083] Table 2. Operating Consumption from the Start of Stable Operation to the End of Operation
[0084] In Example 1, each distillation column achieved self-circulating heat operation during the stable operation phase, eliminating the need for external steam supply and significantly reducing circulating water consumption. Compared to Comparative Example 1, steam consumption was reduced by nearly 100%, circulating water consumption by approximately 93%, with only an increase in power consumption of 3690kW. Based on actual operating data, the system can generate approximately 31.1 million yuan in economic benefits annually and achieve a reduction of approximately 26,100 tons of carbon dioxide emissions, demonstrating significant energy-saving and consumption-reducing effects. Therefore, the system in this example possesses advantages such as stable operation, significant energy-saving effects, outstanding economic benefits, and environmental friendliness, and has broad prospects for industrial application.
[0085] The above provides a detailed description of a heat pump distillation system and method provided in the embodiments of this application. Specific examples have been used in this application to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A heat pump distillation system, characterized in that, The heat pump distillation system includes: Distillation module (10); Storage and delivery module (20), the storage and delivery module (20) is used to store and deliver working medium; An evaporation module (30) is provided, the inlet of which is connected to the outlet of the storage and conveying module (20). A heat boosting module (40) is provided, the inlet of which is connected to the outlet of the evaporation module (30); A reboiling module (50) is used to provide a heat source for the distillation module (10). The reboiling module (50) includes a working fluid reboiler (51). The inlet of the working fluid reboiler (51) is connected to the outlet of the heat boosting module (40), and the outlet of the working fluid reboiler (51) is connected to the inlet of the storage and conveying module (20).
2. The heat pump distillation system according to claim 1, characterized in that, The reboiling module (50) also includes a steam reboiler (52), the inlet of which is connected to an external steam storage device.
3. The heat pump distillation system according to claim 2, characterized in that, The distillation module (10) includes distillation columns (11) arranged in parallel, and the distillation columns (11) are respectively heat-exchange connected to at least one steam reboiler (52) and at least one working fluid reboiler (51).
4. The heat pump distillation system according to claim 3, characterized in that, The evaporation module (30) includes evaporators (31) arranged in parallel, and at least part of the evaporators (31) are heat-exchange connected to the distillation module (10).
5. The heat pump distillation system according to claim 4, characterized in that, The distillation column (11) is equipped with a raw material inlet, a top steam outlet, and a reflux port; A reflux tank is installed on the pipeline between the steam outlet at the top of the tower and the reflux port; The evaporator (31) is located between the top steam outlet of the column and the reflux tank, and is heat-exchange connected to the distillation column (11).
6. The heat pump distillation system according to claim 1, characterized in that, The storage and delivery module (20) includes a storage device (21) and a delivery pump (22); the inlet of the storage device (21) is connected to the outlet of the reboiling module (50), and the storage device (21) is equipped with a cooling mechanism; the inlet of the delivery pump (22) is connected to the storage device (21), and the outlet of the delivery pump (22) is connected to the evaporation module (30).
7. The heat pump distillation system according to claim 1, characterized in that, The heat enhancement module (40) includes a heat pump (41) connected in parallel, and the compressor of the heat pump (41) includes one of a screw compressor, a centrifugal compressor, a Roots compressor, and a reciprocating compressor.
8. A heat pump distillation method, characterized in that, Employing the heat pump distillation system as described in any one of claims 1 to 7, the heat pump distillation method comprises: The working medium in the liquid phase is sent to the evaporation module (30) for evaporation to form a first working medium in the gas phase; The first working medium is sent to the heat boosting module (40) for temperature and pressure boosting to form the second working medium; The second working medium is sent to the working medium reboiler (51) and exchanges heat with the bottom liquid in the distillation module (10) to form a third working medium in the liquid phase; The third working medium is sent to the storage and delivery module (20); Repeat the above steps until the distillation process is complete.
9. The heat pump distillation method according to claim 8, characterized in that, The distillation process includes an initial stage and a stable operation stage; In the initial stage, external steam is introduced into the steam reboiler (52), which together with the working fluid reboiler (51) provides a heat source for the distillation process; During the stable operation phase, the working fluid reboiler (51) independently provides a heat source for the distillation process.
10. The heat pump distillation method according to claim 8, characterized in that, The heat pump distillation method satisfies at least one of the following conditions: (a) The outlet pressure of the heat pump (41) is 0.3 MPaG to 1.0 MPaG; (b) The outlet gas temperature of the heat pump (41) is 77°C to 85°C.
11. The heat pump distillation method according to claim 8, characterized in that, The evaporation pressure of the working medium inside the evaporator (31) is either positive or negative; or, The evaporation pressure of the working medium in the evaporator (31) is 0.01 MPaG~0.05 MPaG.
12. The heat pump distillation method according to claim 8, characterized in that, The working medium contains one of the following: C5 components and refrigerant; The refrigerant includes at least one of R245fa, R134a, and R143a.
13. The heat pump distillation method according to claim 8, characterized in that, The distillation feedstock introduced into the distillation module (10) contains C5 components, and the distillation temperature of the distillation module (10) is 45~80℃.