A vapor-liquid tube plate heat exchanger

Abstract

The application discloses a steam-liquid tube-plate heat exchanger, which adopts an integrated function partition structure, and sequentially sets a steam diffusion distribution A area, a tube heat exchange B area, a plate heat exchange C area and a supercooling heat exchange D area along the steam side heat side medium flow direction; steam sequentially flows through the A, B, C and D areas, and carries out wall heat exchange with the flowing liquid of the steam-liquid heat exchange through the tube wall or the plate wall; the A, B, C and D areas are integrally connected through the internal passage of the tube-plate heat exchanger shell on the steam flow side, sequentially flow and heat exchange, the steam side finally releases heat to form condensate and carry out condensate sensible heat exchange, and finally the condensate flows to the next process. The steam-water heat exchanger of the application realizes the collaborative optimization of multiple performance indexes through structural innovation, breaks through the bottleneck of the prior art, and realizes efficient heat exchange, simple cleaning and quick replacement and maintenance.

Description

Technical Field

[0001] This invention relates to the field of heat exchange equipment technology, specifically to a vapor-liquid tube sheet heat exchanger, which is particularly suitable for industrial fields such as power, refining, metallurgy, pharmaceuticals, food processing and centralized heating, where efficient vapor-water heat exchange, low steam loss and long-term stable operation are required. It falls under the category of high-efficiency and energy-saving heat exchange equipment technology. Background Technology

[0002] In industrial sectors such as power generation, refining, metallurgy, pharmaceuticals, food processing, and district heating, steam-liquid (water) heat exchangers are core equipment for energy transfer and recovery. Their performance directly determines the energy efficiency, operational stability, maintenance costs, and safety levels of the production system. As industrial production upgrades towards higher efficiency, energy conservation, and long-term sustainability, the market is placing increasingly stringent demands on the heat exchange efficiency, fatigue resistance, service life, and steam utilization rate of steam-water heat exchangers.

[0003] Currently, widely used in-situ steam-water heat exchangers in industry are mainly divided into two categories: tube heat exchangers and plate heat exchangers. Both types of equipment have their advantages, but both also have insurmountable technical shortcomings, failing to simultaneously meet the comprehensive requirements of high-efficiency heat exchange, low loss, and long service life. Among them, tube heat exchangers, with their robust structure, excellent high-pressure and high-temperature resistance, and long service life, are widely used in harsh operating conditions. However, limited by traditional co-current or counter-current heat exchange structures, they suffer from low medium flow velocity and heat exchange efficiency, weak subcooling capacity, and significant additional steam consumption. Furthermore, due to their low heat exchange efficiency, tube heat exchangers are large in size and require significant space, limiting their application to users.

[0004] Plate heat exchangers, relying on their compact structural design and large heat exchange area per unit volume, possess advantages such as high heat exchange efficiency and rapid heating. However, their core shortcomings lie in poor fatigue resistance and limited service life. In traditional plate heat exchangers, the plates and sealing components directly bear the impact force, thermal stress, and differential pressure stress caused by high temperature and high pressure differentials. Due to limitations such as flow channel interfaces, stress tends to concentrate locally on the plates, leading to plate deformation and cracking, and accelerated failure and leakage of sealing components. These problems are particularly pronounced under high temperature and high pressure steam-water heat exchange conditions, requiring frequent shutdowns for maintenance and replacement of plates and sealing components. This significantly increases equipment maintenance costs and the risk of production interruption, limiting their application in industrial scenarios with stringent requirements for operational stability and long-term effectiveness.

[0005] Furthermore, traditional heat exchangers generally suffer from the problem of difficult cleaning and maintenance. Impurities and scale remaining in the flow channels are difficult to completely remove, and long-term accumulation will further reduce heat exchange efficiency, accelerate component corrosion and aging, and shorten equipment lifespan. In summary, existing steam-water heat exchangers generally face technical pain points such as low heat exchange efficiency, liquid residue in the flow channels, easy aging and damage of plates and sealing components, large steam loss, short service life, and high maintenance costs. They cannot meet the needs of modern industry for efficient, energy-saving, and long-term stable heat exchange equipment. There is an urgent need for a steam-water heat exchanger that integrates the advantages of tubular and plate heat exchangers and achieves synergistic optimization of multiple performance indicators through structural innovation, in order to break through the existing technical bottlenecks and achieve efficient heat exchange, simple cleaning, and quick replacement and maintenance. Summary of the Invention

[0006] The purpose of this invention is to provide a steam-water heat exchanger that achieves synergistic optimization of multiple performance indicators through structural innovation, thereby breaking through the bottlenecks of existing technologies and achieving efficient heat exchange, simple cleaning, and quick replacement and maintenance.

[0007] The technical solution of this invention is: A vapor-liquid tubesheet heat exchanger is characterized by: an integrated functional zoning structure, wherein a vapor diffusion distribution zone A, a tube heat exchange zone B, a plate heat exchange zone C, and a subcooling heat exchange zone D are sequentially arranged along the flow direction of the vapor-side hot-side medium; the vapor flows sequentially through zones A, B, C, and D, and undergoes indirect heat exchange with the subcooled liquid on the vapor-liquid side through the tube wall or plate wall; the zones A, B, C, and D are interconnected on the vapor flow side through an integrated channel inside the tubesheet heat exchanger shell, and flow and exchange heat in the order of A, B, C, and D, with the vapor side ultimately releasing heat to form condensate and undergoing sensible heat exchange, and finally the condensate flows to the next process.

[0008] The steam diffusion distribution zone A adopts a diffusion box structure, which can be a box of various shapes including circular, arc, or square. The side of the box along the steam flow direction is connected to the steam pipeline as the steam inlet. After the steam enters the box, it is diffused and evenly distributed, and then flows to the outlet direction of the box. The outlet direction is connected to the inlet of the tubular heat exchange zone B or exists as a whole.

[0009] When space is limited or other requirements exist, the steam diffusion distribution zone A can be combined with the tubular heat exchange zone B, using the shell of the tubular heat exchanger as the steam diffusion distribution zone, which simultaneously acts on zones B and C.

[0010] The tubular steam heat exchanger in zone B uses a tubular heat exchanger for heat exchange. Steam flows along the shell direction of the tubular steam heat exchanger in zone B, which is connected to the outlet of the steam diffusion and distribution zone A. The heat exchange tube bundle is placed in the shell, and the tube bundle is parallel to or at a certain angle to the steam flow direction. The steam flows through the inside or outside of the tube bundle and exchanges heat with the cold liquid on the outside or inside of the tube on the other side of the tube through the tube wall. Then, it continues to flow along the shell direction of the tubular heat exchanger in zone B towards the inlet direction of the plate heat exchanger in zone C, and provides steam diffusion and distribution for the steam flowing into zone C. The plate steam heat exchanger C zone uses a plate heat exchanger for heat exchange. Steam flows along the inlet direction of the plate steam heat exchanger C zone, which is connected to the outlet of the tubular heat exchanger B zone, and enters between different plates to exchange heat with the cold liquid on the other side of the plates, which is isolated from the steam. Because the plates adopt corrugated or uneven structures or other plate heat exchanger structures that increase turbulent heat exchange, the heat exchange efficiency is improved. The steam begins to condense along the flow direction and releases heat to the cold liquid on the other side of the plates. Along the steam flow direction, the steam condenses into condensate or a vapor-liquid mixture and flows to the subcooled heat exchanger D zone. The subcooled heat exchange zone D employs plate heat exchangers, tube heat exchangers, or a combination of plate and tube heat exchangers. The condensed liquid or steam-water mixture formed after steam condensation flows out from the outlet of the plate heat exchange zone C and enters the subcooled heat exchange zone D. When the subcooled heat exchange zone D uses a plate heat exchanger, the plate heat exchange component is an extension of the core of the plate heat exchange zone C, achieving subcooling of the condensate through wall heat exchange. When using a plate heat exchanger, the subcooled heat exchange zone D may also be a separate new plate heat exchanger or core that receives the condensate or its steam-liquid mixture from the outlet of the plate heat exchange zone C. Through the plate wall, the condensate or vapor-liquid mixture on one side exchanges heat with the cold liquid on the other side to further absorb the heat enthalpy value in the condensate; or the subcooling heat exchange zone D uses a tubular heat exchanger for heat exchange, that is, the condensate or vapor-liquid mixture at the outlet of the plate heat exchange zone C enters the subcooling heat exchange zone D, and its condensate or vapor-liquid mixture enters the tube bundle or outside the tube bundle, and exchanges heat with the cold liquid through the tube bundle wall; or the subcooling heat exchange zone D, depending on the operating conditions and the design and layout of the heat exchanger, adopts one or more sections of plate heat exchange and another or more sections of tubular heat exchange.

[0011] A deep subcooling heat exchange zone E is further provided after the subcooling heat exchange zone D; the deep subcooling heat exchange zone E adopts a plate heat exchanger, a tube heat exchanger, or a combination of plate and tube heat exchangers; the condensed steam, or the steam-water mixture contained therein, flows out of the outlet of the subcooling heat exchange zone D and into the deep subcooling heat exchange zone E; when the deep subcooling heat exchange zone E uses a plate heat exchanger, the plate heat exchange component is an extension of the core of the deep subcooling heat exchange zone E, achieving further cooling of the steam-water mixture in zone E through wall heat exchange, turning it into condensate and then passing it through the condensate; when the deep subcooling heat exchange zone E uses a plate heat exchanger, it may be... In the D zone of the plate subcooling heat exchanger, the condensate at the outlet is separated into a new plate heat exchanger or core package. Through the plate walls, the condensate on one side exchanges heat with the cold liquid on the other side to further absorb the heat enthalpy value in the condensate. Alternatively, in the E zone of the deep subcooling heat exchanger, a tubular heat exchanger is used for heat exchange. That is, the condensate at the outlet of the subcooling heat exchanger D enters the deep subcooling heat exchanger E, and its condensate or steam-water mixture enters the tube bundle or outside the tube bundle, where it exchanges heat with the cold liquid through the tube bundle walls. Alternatively, depending on the operating conditions and the design and arrangement of the heat exchangers, one or more sections of the deep subcooling heat exchanger E may use plate heat exchangers, while another or more sections may use tubular heat exchangers.

[0012] Further, a condensate discharge zone F is set after the deep subcooling heat exchange zone E; the condensate discharge zone F has a condensate collection box, which is a separate box or part of the subcooling heat exchange zone D or the deep subcooling heat exchange zone E; a condensate discharge port is provided at the bottom of the box to facilitate the discharge of condensate out of the heat exchanger after the heat is released.

[0013] In vapor-liquid heat exchange, the vapor is the hot-side medium, typically superheated or high-temperature, high-pressure steam; in some cases, it may be steam with a pressure lower than atmospheric pressure. During its flow, it continuously releases and changes heat. It may also mix with steam, steam-water mixtures, or condensate from other sections, exchanging heat with the cold-side liquid.

[0014] In vapor-liquid heat exchange, the liquid refers to the cold-side medium. This is typically water, but other liquid working fluids can also be used. This cold medium can be a single working fluid that flows through the BCDE zones to exchange heat with the vapor-side working fluid. The flow sequence of the liquid can be determined based on actual operating conditions and design requirements; it is not necessarily required by the EDCB sequence or any other order, and there are no strict sequence restrictions. Multiple liquids can also serve as the cold medium, exchanging heat with the vapor-side hot medium in the BCDE zones according to their own needs, temperature gradients, or other design requirements. Liquids can communicate between the BCDE zones via cold-liquid interconnection channels.

[0015] Between the steam inlet and outlet (including the steam inlet and outlet) of the tubular heat exchanger in zone B, a steam distribution plate is further arranged. The steam distribution plate is arranged in the cross section in the direction of steam flow. The steam distribution plate has a porous structure, and the steam is redistributed through the pores to achieve a more uniform steam distribution after the steam distribution plate.

[0016] In the deep subcooling heat exchange zone E, along the steam flow direction, at the rear end of zone E, an inverted baffle is installed; the inverted baffle maintains a certain flow height with the bottom surface, so that the liquid or gas can gather upwards and stay for more time to be further condensed and subcooled.

[0017] Level gauges should be installed in the condensate discharge zone F, the subcooled heat exchange zone D, or the deep subcooled heat exchange zone E, especially in zone F, to facilitate the monitoring and control of the time, flow rate, temperature, etc. of the discharged condensate.

[0018] In zones A, B, C, D, E, and F, regardless of whether the housing is used for cold or hot testing, a removable structure with bolted covers can be adopted for easy inspection and cleaning. Each zone (A, B, C, D, E, F) can be modularly designed to facilitate replacement of damaged parts or timely repair, maintenance, and cleaning.

[0019] In zones A, B, C, D, E, F, and other pipelines and areas of the heat exchanger, temperature, pressure, and other instruments or components can be installed as needed to facilitate monitoring and control of the heat exchanger operation.

[0020] This invention is not simply a splicing of tubular and plate modules, but a systematic multi-region collaborative design. It addresses the following issues: First, uneven steam distribution easily leads to excessively high local heat exchange intensity, exacerbating stress concentration and component wear; second, unreasonable flow channel layout still results in dead zones and liquid residue, limiting the improvement in heat exchange efficiency; third, the lack of an efficient steam-water separation and drainage control mechanism fails to fundamentally solve the problems of steam loss and steam carried over in the drainage; and fourth, the absence of stress optimization design results in significant fatigue damage to plates, sealing components, and the shell, hindering long-term stable operation of the equipment.

[0021] In industrial production and energy utilization, vapor-liquid (water) heat exchange is one of the core technological processes. As a critical piece of equipment, the heat exchanger's heat exchange efficiency, operational stability, fatigue resistance, and service life directly impact the energy consumption, operating costs, and safe production of the entire production system. Addressing the technical pain points of traditional vapor-liquid (water) heat exchangers, such as low heat exchange efficiency, easy aging and damage of plates, limited sensible heat recovery from condensate, high steam consumption, and short service life, this invention integrates the advantages of tubular and plate heat exchangers. Through an innovative multi-zone collaborative design, it achieves integrated functions of high-efficiency heat exchange, stress optimization, and condensate separation. Simultaneously, it maximizes the recovery of sensible enthalpy from the condensate. This saves steam consumption, effectively reduces heat exchanger costs, and improves heat exchanger safety and reliability. It can be widely applied in various industrial scenarios requiring high-temperature and high-pressure vapor-liquid heat exchange, and is particularly suitable for operating conditions with stringent requirements for equipment fatigue resistance, operational stability, and energy-saving effects, providing technical support for the energy efficiency upgrade and long-term operation of industrial heat exchange systems. Simultaneously, it is also suitable for applications where plate heat exchangers cannot be used directly for the entire heat exchange process, such as under conditions of thermal stress or impact. Tube heat exchange technology is used to compensate for the shortcomings of plate heat exchangers. This heat exchanger can also be used under some low-pressure conditions. For vapor-liquid heat exchange processes requiring subcooling, boiling, or large liquid storage, this heat exchanger can also be used, such as the reboiling section of a reboiler or a large-capacity condensate storage section. A tube-plate combination is used to compensate for the limited volume of plate heat exchangers, while tube heat exchangers are used to increase the volume.

[0022] The vapor-liquid tube sheet heat exchanger of the present invention has the following advantages compared with the prior art: 1. This invention provides a vapor-liquid tube-plate heat exchanger, employing a tube-plate combination. The tube portion effectively resists the impact of high-temperature, high-pressure steam, leveraging the robust and durable characteristics of tube heat exchangers. Due to the larger tube diameter or gaps between tubes in the tube heat exchanger, it can withstand harsh liquid and impurity impacts, providing a certain degree of protection for the plate heat exchanger. Its steam diffusion distribution area also effectively adapts to steam impacts.

[0023] 2. This invention provides a vapor-liquid tube-plate heat exchanger. Initially, the tube-type heat exchanger effectively resists steam impact and de-cools the steam. After the steam is de-cooled, the plate heat exchanger technology ensures reliable and safe operation while leveraging the advantages of its small size and high heat exchange efficiency. It efficiently and rapidly cools the steam and heats the liquid. In some cases, the heat exchanger materials can even be different. For example, the tube-type heat exchange area under harsh conditions can use high-temperature impact-resistant and thickened materials, while the plate-type area can use ordinary materials and processes.

[0024] 3. This invention provides a vapor-liquid tube-plate heat exchanger. Structurally, after the plate heat exchanger, a subcooling heat exchange zone D and a deep subcooling heat exchange zone F are incorporated, which are not well-suited for tube heat exchangers. This not only utilizes the latent heat of steam but also effectively utilizes the sensible heat in the condensate. This allows for further heat exchange between the condensate and the heated liquid, effectively reducing steam consumption and achieving greater energy savings and emission reductions. Simultaneously, the saved high-quality steam can be used for power generation and other purposes, achieving energy cascade utilization, which aligns with national policies and dual-carbon goals.

[0025] 4. This invention provides a vapor-liquid tube sheet heat exchanger, which is also more conducive to condensate recovery, thus achieving water conservation and emission reduction. It solves the mechanical problems of heat exchange equipment vibration, fatigue, and excessive condensate configuration caused by high-parameter steam. 5. The present invention provides a vapor-liquid tube sheet heat exchanger in which zones A, B, C, D, E, and F can be modularly designed and individually replaced, especially zone B, which is a tube heat exchanger. Furthermore, each zone can employ a detachable threaded connection structure, facilitating easy access for observation, cleaning, maintenance, and replacement of the heat exchange components of the tube heat exchanger.

[0026] The advantages mentioned above are also evident in applications where the liquid being heated is heated to produce steam, such as reboilers or evaporators. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of a vertical embodiment of the present invention.

[0029] Figure 2 This is a structural schematic diagram of another horizontal product of the present invention.

[0030] In the diagram: 1. Steam inlet; 2. Steam diffusion distribution zone A; 3. Steam distribution orifice plate; 4. Tubular heat exchanger zone B; 5. Plate heat exchanger zone C; 6. Subcooling heat exchanger zone D; 7. Deep subcooling heat exchanger zone E; 8. Condensate discharge zone F; 9. Inverted baffle; 10. Level gauge; 11. Condensate outlet; 12. Heated water inlet; 13. Heated water outlet; 14. Cold liquid connection channel; 15. Lifting lug; 16. Support. Detailed Implementation

[0031] A vapor-liquid tubesheet heat exchanger adopts an integrated functional zoning structure, with a vapor diffusion distribution zone A, a tube heat exchange zone B, a plate heat exchange zone C, and a subcooling heat exchange zone D arranged sequentially along the flow direction of the medium on the vapor and hot sides. Steam flows through zones A, B, C, and D in sequence, and exchanges heat with the subcooled liquid on the vapor-liquid side through the tube wall or plate wall. Zones A, B, C, and D are interconnected on the vapor flow side through an integrated channel inside the tubesheet heat exchanger shell, and flow and exchange heat in the order of A, B, C, and D. The vapor side eventually releases heat to form condensate and undergoes sensible heat exchange with the condensate. Finally, the condensate flows to the next process.

[0032] The steam diffusion distribution zone A adopts a diffusion box structure, which can be a box of various shapes including circular, arc, or square. The side of the box along the steam flow direction is connected to the steam pipeline as the steam inlet. After the steam enters the box, it is diffused and evenly distributed, and then flows to the outlet direction of the box. The outlet direction is connected to the inlet of the tubular heat exchange zone B or exists as a whole.

[0033] When space is limited or other requirements exist, the steam diffusion distribution zone A can be combined with the tubular heat exchange zone B, using the shell of the tubular heat exchanger as the steam diffusion distribution zone, which simultaneously acts on zones B and C.

[0034] The tubular steam heat exchanger in zone B uses a tubular heat exchanger for heat exchange. Steam flows along the shell direction of the tubular steam heat exchanger in zone B, which is connected to the outlet of the steam diffusion and distribution zone A. The heat exchange tube bundle is placed in the shell, and the tube bundle is parallel to or at a certain angle to the steam flow direction. The steam flows through the inside or outside of the tube bundle and exchanges heat with the cold liquid on the outside or inside of the tube on the other side of the tube through the tube wall. Then, it continues to flow along the shell direction of the tubular heat exchanger in zone B towards the inlet direction of the plate heat exchanger in zone C, and provides steam diffusion and distribution for the steam flowing into zone C. The plate steam heat exchanger C zone uses a plate heat exchanger for heat exchange. Steam flows along the inlet direction of the plate steam heat exchanger C zone, which is connected to the outlet of the tubular heat exchanger B zone, and enters between different plates to exchange heat with the cold liquid on the other side of the plates, which is isolated from the steam. Because the plates adopt corrugated or uneven structures or other plate heat exchanger structures that increase turbulent heat exchange, the heat exchange efficiency is improved. The steam begins to condense along the flow direction and releases heat to the cold liquid on the other side of the plates. Along the steam flow direction, the steam condenses into condensate or a vapor-liquid mixture and flows to the subcooled heat exchanger D zone. The subcooled heat exchange zone D employs plate heat exchangers, tube heat exchangers, or a combination of plate and tube heat exchangers. The condensed liquid or steam-water mixture formed after steam condensation flows out from the outlet of the plate heat exchange zone C and enters the subcooled heat exchange zone D. When the subcooled heat exchange zone D uses a plate heat exchanger, the plate heat exchange component is an extension of the core of the plate heat exchange zone C, achieving subcooling of the condensate through wall heat exchange. When using a plate heat exchanger, the subcooled heat exchange zone D may also be a separate new plate heat exchanger or core that receives the condensate or its steam-liquid mixture from the outlet of the plate heat exchange zone C. Through the plate wall, the condensate or vapor-liquid mixture on one side exchanges heat with the cold liquid on the other side to further absorb the heat enthalpy value in the condensate; or the subcooling heat exchange zone D uses a tubular heat exchanger for heat exchange, that is, the condensate or vapor-liquid mixture at the outlet of the plate heat exchange zone C enters the subcooling heat exchange zone D, and its condensate or vapor-liquid mixture enters the tube bundle or outside the tube bundle, and exchanges heat with the cold liquid through the tube bundle wall; or the subcooling heat exchange zone D, depending on the operating conditions and the design and layout of the heat exchanger, adopts one or more sections of plate heat exchange and another or more sections of tubular heat exchange.

[0035] A deep subcooling heat exchange zone E is further provided after the subcooling heat exchange zone D; the deep subcooling heat exchange zone E adopts a plate heat exchanger, a tube heat exchanger, or a combination of plate and tube heat exchangers; the condensed steam, or the steam-water mixture contained therein, flows out of the outlet of the subcooling heat exchange zone D and into the deep subcooling heat exchange zone E; when the deep subcooling heat exchange zone E uses a plate heat exchanger, the plate heat exchange component is an extension of the core of the deep subcooling heat exchange zone E, achieving further cooling of the steam-water mixture in zone E through wall heat exchange, turning it into condensate and then passing it through the condensate; when the deep subcooling heat exchange zone E uses a plate heat exchanger, it may be... In the D zone of the plate subcooling heat exchanger, the condensate at the outlet is separated into a new plate heat exchanger or core package. Through the plate walls, the condensate on one side exchanges heat with the cold liquid on the other side to further absorb the heat enthalpy value in the condensate. Alternatively, in the E zone of the deep subcooling heat exchanger, a tubular heat exchanger is used for heat exchange. That is, the condensate at the outlet of the subcooling heat exchanger D enters the deep subcooling heat exchanger E, and its condensate or steam-water mixture enters the tube bundle or outside the tube bundle, where it exchanges heat with the cold liquid through the tube bundle walls. Alternatively, depending on the operating conditions and the design and arrangement of the heat exchangers, one or more sections of the deep subcooling heat exchanger E may use plate heat exchangers, while another or more sections may use tubular heat exchangers.

[0036] Further, a condensate discharge zone F is set after the deep subcooling heat exchange zone E; the condensate discharge zone F has a condensate collection box, which is a separate box or part of the subcooling heat exchange zone D or the deep subcooling heat exchange zone E; a condensate discharge port is provided at the bottom of the box to facilitate the discharge of condensate out of the heat exchanger after the heat is released.

[0037] In vapor-liquid heat exchange, the vapor is the hot-side medium, typically superheated or high-temperature, high-pressure steam; in some cases, it may be steam with a pressure lower than atmospheric pressure. During its flow, it continuously releases and changes heat. It may also mix with steam, steam-water mixtures, or condensate from other sections, exchanging heat with the cold-side liquid.

[0038] In vapor-liquid heat exchange, the liquid refers to the cold-side medium. This is typically water, but other liquid working fluids can also be used. This cold medium can be a single working fluid that flows through the BCDE zones to exchange heat with the vapor-side working fluid. The flow sequence of the liquid can be determined based on actual operating conditions and design requirements; it is not necessarily required by the EDCB sequence or any other order, and there are no strict sequence restrictions. Multiple liquids can also serve as the cold medium, exchanging heat with the vapor-side hot medium in the BCDE zones according to their own needs, temperature gradients, or other design requirements. Liquids can communicate between the BCDE zones via cold-liquid interconnection channels.

[0039] Between the steam inlet and outlet (including the steam inlet and outlet) of the tubular heat exchanger in zone B, a steam distribution plate is further arranged. The steam distribution plate is arranged in the cross section in the direction of steam flow. The steam distribution plate has a porous structure, and the steam is redistributed through the pores to achieve a more uniform steam distribution after the steam distribution plate.

[0040] In the deep subcooling heat exchange zone E, along the steam flow direction, at the rear end of zone E, an inverted baffle is installed; the inverted baffle maintains a certain flow height with the bottom surface, so that the liquid or gas can gather upwards and stay for more time to be further condensed and subcooled.

[0041] Level gauges should be installed in the condensate discharge zone F, the subcooled heat exchange zone D, or the deep subcooled heat exchange zone E, especially in zone F, to facilitate the monitoring and control of the time, flow rate, temperature, etc. of the discharged condensate.

[0042] In zones A, B, C, D, E, and F, regardless of whether the housing is used for cold or hot testing, a removable structure with bolted covers can be adopted for easy inspection and cleaning. Each zone (A, B, C, D, E, F) can be modularly designed to facilitate replacement of damaged parts or timely repair, maintenance, and cleaning.

[0043] In zones A, B, C, D, E, F, and other pipelines and areas of the heat exchanger, temperature, pressure, and other instruments or components can be installed as needed to facilitate monitoring and control of the heat exchanger operation.

[0044] During operation, steam enters zone A (steam inlet 1) and then (steam diffusion and distribution zone 2). Optionally, steam passes through the steam distribution orifice plate (steam distribution plate 3) and enters zone B (tubular heat exchanger 4). In this zone, steam located outside or inside the tubes exchanges heat with liquid located inside or outside the tubes. Optionally, the steam distribution orifice plate (steam distribution plate 3) can be positioned at the steam inlet or outlet, or between the inlet and outlet, in zone B. After heat exchange in zone B, the steam's temperature decreases, its impact is reduced, and its flow velocity decreases relative to the velocity entering the heat exchanger through the pipe, resulting in high distribution uniformity. Then, it enters zone C (plate heat exchanger 5). In zone C, steam and liquid are separated on opposite sides of the plates, undergoing indirect surface heat exchange without mixing. Here, the plate heat exchanger leverages its small size and high heat exchange efficiency, achieving highly efficient heat exchange.

[0045] Selectively, after heat exchange in zone C of the plate heat exchanger, steam and water become a steam-water mixture, which then further exchanges heat in zone D (subcooling heat exchanger). In zone D, the steam-water mixture exchanges heat with the cold liquid, becoming entirely or mostly condensate, and undergoes a certain degree of subcooling heat exchange. The condensate then exchanges heat with the water on the cold side, transferring the sensible heat from the condensate to the water. The heat exchanger in zone D can be either a tube or a plate heat exchanger, depending on the requirements. For example, a tube heat exchanger is chosen when a larger volume is needed. A plate heat exchanger is chosen when the volume requirement is small but the heat exchange efficiency requirement is high.

[0046] Selectively, in the subcooling heat exchange zone D, the condensate, having undergone heat exchange, retains a certain temperature and sometimes even a small amount of steam-water mixture, thus still possessing a certain enthalpy. At this point, the condensate can enter zone 7, the deep subcooling heat exchange zone E. In zone E, the condensate further exchanges heat with the cold-side water; the smaller the temperature difference (the difference between the condensate outlet temperature and the cold-side inlet water temperature), the more complete the heat exchange (recovery). The condensate then enters zone 8, the condensate discharge zone F. Optionally, a baffle plate can be installed in zone F. The baffle plate can be installed at the condensate outlet in zone E or between the inlet and outlet to control the condensate discharge flow rate, further controlling the liquid level and condensate residence time in zone F to ensure sufficient heat exchange. The condensate then proceeds to the next process.

[0047] Optionally, a level gauge can be installed in zone 8 (condensate discharge area F) to monitor the condensate level and link with external controls. The condensate is then discharged through zone 11 (condensate outlet). The condensate then proceeds to the next process. The medium on the cold side is typically water, but other liquids are also possible. Two of the four zones (B, C, D, E) are equipped with zones 12 (heated water inlet) and 13 (heated water outlet). In areas without inlets or outlets, a zone 14 (cold liquid connection channel) is provided to ensure cold liquid flow and heat exchange in different zones. The cold liquid connection channel can be an external pipe or an internal channel, depending on the design and specific circumstances.

[0048] The steam diffusion and distribution zone A can be considered as an arc-shaped cavity or a cavity of other shapes, serving the function of steam diffusion and distribution. Steam in zone A can change its flow direction, such as by deflecting at 90 degrees, or it can remain in its original flow direction. It itself serves the function of steam diffusion and distribution and can be used in conjunction with zone B. That is, it diffuses and distributes in zone B, while also providing pre-distribution diffusion for zone C.

[0049] Steam distribution orifice plates are porous metal plates with holes of equal or unequal diameters. They can also be square or other shapes. Based on calculations and actual operating conditions, the orifice plates are evenly or discretely distributed across the metal plate, serving to distribute and equalize the steam flow. They can be positioned at the steam inlet or outlet, or between the inlet and outlet, in zone B of a tubular heat exchanger.

[0050] In zone B of the tubular heat exchanger, the hot and cold fluids can be located on opposite sides of the tube wall. Typically, steam flows along the outside of the tube, which is horizontally positioned within the steam flow path to improve the steam scouring coefficient, further enhancing the tube's heat transfer coefficient and efficiency. Other arrangements can be used as needed, with steam flowing inside the tube and coolant outside. In this case, the steam distribution orifice plate can be selectively omitted, depending on the specific circumstances. Furthermore, the tubes can be of various types, including plain tubes, corrugated tubes, finned tubes, and even the latest three-ribbed finned tubes, to suit different operating conditions and heat exchange needs.

[0051] The plate heat exchanger in zone C adopts the plate heat exchange principle and can use various heat exchanger plate types such as pressed corrugated plates and bubble heat exchanger plates. It uses gaskets, welding seals, or other sealing forms and combinations of sealing forms to perform heat exchange as a plate heat exchanger.

[0052] The subcooling heat exchange zone D can employ plate or tubular heat exchange technology. Using tubular heat exchange technology works similarly to zone B, while using plate heat exchange technology works similarly to zone C. When the cooling effect is good on the hot side, it consists entirely of condensate. Under certain operating conditions, it consists of a mixture of condensate and some steam.

[0053] The deep subcooling heat exchange zone E can employ plate or tubular heat exchange technology. Using tubular heat exchange technology operates on a similar principle to zone B, while using plate heat exchange technology operates on a similar principle to zone C. When the cooling effect is good, the hot side of this zone contains only condensate. Under certain operating conditions, it contains a mixture of condensate and some steam-water mixture. Regardless of the specific composition, this zone further cools the working fluid flowing from the hot side of subcooling heat exchange zone D into deep subcooling heat exchange zone E, and subcools the condensate, converting the steam-water mixture back into condensate.

[0054] The inverted baffle, from top to bottom, seals the outlet of the deep subcooling heat exchange zone E. By throttling, it limits the flow rate of condensate out of zone E and adjusts (extends) the time that condensate stays in zone E, making zone E more conducive to deep subcooling and exchanging heat (sensible heat) from the condensate.

[0055] The aforementioned condensate discharge zone F is a cavity for storing condensate. When no heat exchanger is installed, it is simply zone F; when a heat exchanger is installed, it becomes integrated with zone E (or even zone D). Its function is to store condensate and then discharge it. Sometimes, certain processes require a separate space to store condensate. When zone F is not specified, the condensate outlet can be directly located in zone E.

[0056] This equipment can also be used in reboilers, where the heated liquid vaporizes in the plate or tube section. Considering the impact resistance of plate heat exchangers, it is mostly used in the tube section. In this case, the heating medium can flow inside the tubes, while the saturated liquid flows outside, utilizing a larger space to generate steam. This avoids the disadvantage of a small plate heat exchanger volume, which is not conducive to evaporation and phase change. Of course, using saturated liquid inside the tubes and the heating medium outside is also acceptable. Due to the subcooling of the condensate, the reboiling steam consumption is reduced.

[0057] At this point, the steam from zone A is not necessarily superheated steam. After entering zone B, a reboiler is formed on the cold liquid side of zone B (the cold liquid can be located inside or outside the tubes), effectively avoiding the space limitations, thermal stress fatigue, and other damage problems of plate reboilers. This heat exchanger can be used for vapor (including synthesis vapor or gas) to liquid (including liquid vapor in the reboiler) heat exchange in various industries. Similar to the uses of reboilers, this equipment can also be used for evaporators operating under negative pressure.

[0058] Taking the raw water heater in a thermal power plant as an example, the extraction steam temperature from the turbine is approximately 320°C, 8 bar (A). Figure 1For example, when the steam enters the steam diffusion distribution zone B through the steam inlet 1, it gains a relatively large diffusion space. Then, under the action of the steam distribution plate 3, it enters the tube heat exchanger zone B more evenly. In zone B, the tube bundle is placed horizontally in the steam along the steam flow direction and is laterally flushed by the steam. The steam transfers heat to the raw water inside the tubes, reducing its own temperature. According to the design conditions, the steam temperature can be reduced to approximately 171℃ (saturation temperature is 170.4℃), close to the saturation temperature. It then enters the plate heat exchanger zone C, where the high-efficiency heat exchange characteristics of the plate heat exchanger are utilized. After sufficient heat exchange, the steam-water mixture enters the subcooled zone D. In this zone, the steam-water mixture is further condensed into condensate by the cold-side raw water, thus releasing heat fully. That is, the raw water fully absorbs heat, the steam fully releases heat, and all latent heat is released. A portion of the sensible heat of the condensate is also released. Along the flow direction, the condensate enters the deep subcooled zone E. At this point, the heat from the condensate can be further exchanged with the raw water. Since the raw water itself only requires a heating temperature of 20-30℃, the heat from the condensate can still be fully absorbed in zone E, which avoids additional steam consumption. During the heating process, the raw water can be heated in the required order in zones B, C, D, E, and F to gradually increase the temperature. For example, it can be heated first in zone B, so that when it enters zone C, its water temperature has already risen, avoiding excessive temperature difference between the two ends of the plate heat exchanger wall, thus preventing thermal stress.

[0059] Similarly, when used to heat another liquid with steam, causing it to boil again (i.e., in a reboiler), the liquid can first fully absorb heat from the condensate in the FED zone, saving steam consumption. When it enters zone C, it is already close to boiling saturation. Upon entering zone B, it begins to boil under the heating of the tube bundle. Because the shell space of the tube bundle heat exchanger is large and the tube bundle is easy to clean (liquids that are reboiled are prone to scaling, such as flash evaporation in zero-discharge wastewater), the advantages of the tube heat exchanger are utilized, while also saving steam, similar to the case of raw water heating.

[0060] Furthermore, the liquid used for vapor-liquid heating can be the same liquid, or different liquids can be used depending on the actual situation to facilitate actual working conditions or energy gradient utilization. This does not affect the protective nature of this patent.

[0061] Furthermore, the "vapor" in the aforementioned vapor-liquid heat exchanger primarily refers to steam, especially superheated steam. In practical applications, it can also be the vaporization product of other substances, such as oil vapor from oil refining.

[0062] Figure 1 The heat exchangers in the design are arranged vertically (generally based on the arrangement of plate heat exchangers), but in practical applications, they can also be... Figure 2The horizontal layout design shown (horizontal layout of plate heat exchangers) operates on the same principle.

[0063] Furthermore, regardless of whether the plate heat exchanger is arranged horizontally or vertically, the inlet of its steam-side flow channel is entirely located in the steam-side flow channel of the tube sheet heat exchanger. Figure 1 The steam-side inlet of the plate heat exchanger perfectly matches the outlet of zone B. Figure 2 In the plate heat exchanger, the plate heat exchange core bundle in zone C lies horizontally. Sometimes, for fixation, the core bundle requires a fixed outer shell, which makes the steam inlet of the core bundle smaller than the outlet of zone B in the tube heat exchanger or the inlet of zone C in the plate heat exchanger. This special type of core bundle is frequently used in practice, resulting in a smaller steam inlet than the outlet of zone B in the tube heat exchanger or the inlet of zone C in the plate heat exchanger, but this does not affect the protective nature of this patent.

[0064] Furthermore, the gaseous working medium transforms into a condensate and is discharged, with the fluid continuously flowing within the casing in each region. The coolant can sometimes flow through these regions via coolant interconnection channels. These channels can be built into the casing and invisible externally, or they can be external pipes outside the casing, with interfaces in each region for coolant transfer.

[0065] Furthermore, the lower surfaces of the subcooled heat exchange zone D, the deep subcooled heat exchange zone E, and the condensate discharge zone F may not be on the same plane. For example, the bottom surface of zone F may be lower than that of zone E, resulting in a lower liquid level and a larger liquid capacity in zone F to meet operational requirements. This is especially important for operational conditions where both volume and time requirements for liquid capacity are specified.

[0066] The level gauge can also be installed in zone D or zone E, depending on the specific operating conditions and design requirements. When used with a regulating valve, a steam trap is no longer needed, simplifying the system, reducing costs, and improving reliability. Furthermore, this tube sheet heat exchanger, based on the plate heat exchanger layout, can be placed horizontally. Figure 2 It can also be placed upright. Figure 1 Regardless of whether it is placed vertically or horizontally, area A and area B are both part of it. When the space is small, areas A and B can be combined into one. That is, the shell space of area B in the tubular heat exchanger also serves as a distribution area. For example, steam flows outside the pipe and water flows inside the pipe. The shell serves as a diffusion and distribution space, which does not affect its protective function.

[0067] Furthermore, the tube sheet heat exchanger can be assembled in modules, with each section assembled separately, or it can be manufactured as a whole, especially the shell, depending on the operating conditions and requirements.

[0068] Furthermore, this tube sheet heat exchanger can be used as a reboiler. Its hot side (heat source side) contains steam, while the cold side (reboiler side) initially contains liquid. Before entering zone C and then zone B, the liquid is heated by the plate heat exchanger and then enters zone B (either inside or outside the tubes) for boiling and steam generation. This avoids reboiling within the plate heat exchanger, thus mitigating problems caused by stress, space limitations, etc., and leveraging the advantages of the tube heat exchanger in zone B. The steam can then flow out through an opening at the top of zone B, or it can collect inside the tube bundle and flow out from the side or other locations.

[0069] Furthermore, neither the vapor-liquid mixture nor its mixture mentioned in this article is subject to pressure restrictions; it can operate at a pressure lower than one atmosphere. In this case, a vacuum (non-condensable gas) port is installed on the heat exchanger.

Claims

1. A vapor-liquid tube sheet heat exchanger, characterized in that: The system adopts an integrated functional zoning structure, with steam diffusion distribution zone A, tubular heat exchange zone B, plate heat exchange zone C, and subcooling heat exchange zone D arranged sequentially along the steam-side and hot-side medium flow direction. Steam flows through zones A, B, C, and D in sequence, and undergoes indirect heat exchange with the subcooled liquid on the steam-liquid side through the tube wall or plate wall. Zones A, B, C, and D are interconnected on the steam flow side through the internal channels of the tube-plate heat exchanger shell, and flow and exchange heat in the order of A, B, C, and D. The steam side ultimately releases heat to form condensate and undergoes sensible heat exchange with the condensate. Finally, the condensate flows to the next process.

2. The vapor-liquid tube sheet heat exchanger according to claim 1, characterized in that: The steam diffusion distribution zone A adopts a diffusion box structure, which can be a box of various shapes including circular, arc, or square. The side of the box along the steam flow direction is connected to the steam pipeline as the steam inlet. After the steam enters the box, it is diffused and evenly distributed, and then flows to the outlet direction of the box. The outlet direction is connected to the inlet of the tubular heat exchange zone B or exists as a whole.

3. A vapor-liquid tube sheet heat exchanger according to claim 2, characterized in that: When space is limited or other requirements exist, the steam diffusion distribution zone A can be combined with the tubular heat exchange zone B, using the shell of the tubular heat exchanger as the steam diffusion distribution zone, which simultaneously acts on zones B and C.

4. A vapor-liquid tube sheet heat exchanger according to claim 1, characterized in that: The tubular steam heat exchanger in zone B uses a tubular heat exchanger for heat exchange. Steam flows along the shell direction of the tubular steam heat exchanger in zone B, which is connected to the outlet of the steam diffusion and distribution zone A. The heat exchange tube bundle is placed in the shell, and the tube bundle is parallel to or at a certain angle to the steam flow direction. The steam flows through the inside or outside of the tube bundle and exchanges heat with the cold liquid on the outside or inside of the tube on the other side of the tube through the tube wall. Then, it continues to flow along the shell direction of the tubular heat exchanger in zone B towards the inlet direction of the plate heat exchanger in zone C, and provides steam diffusion and distribution for the steam flowing into zone C. The plate steam heat exchanger C zone uses a plate heat exchanger for heat exchange. Steam flows along the inlet direction of the plate steam heat exchanger C zone, which is connected to the outlet of the tubular heat exchanger B zone, and enters between different plates to exchange heat with the cold liquid on the other side of the plates, which is isolated from the steam. Because the plates adopt corrugated or uneven structures or other plate heat exchanger structures that increase turbulent heat exchange, the heat exchange efficiency is improved. The steam begins to condense along the flow direction and releases heat to the cold liquid on the other side of the plates. Along the steam flow direction, the steam condenses into condensate or a vapor-liquid mixture and flows to the subcooled heat exchanger D zone. The subcooled heat exchange zone D employs plate heat exchangers, tube heat exchangers, or a combination of plate and tube heat exchangers. The condensed liquid or steam-water mixture formed after steam condensation flows out from the outlet of the plate heat exchange zone C and enters the subcooled heat exchange zone D. When the subcooled heat exchange zone D uses a plate heat exchanger, the plate heat exchange component is an extension of the core of the plate heat exchange zone C, achieving subcooling of the condensate through wall heat exchange. When using a plate heat exchanger, the subcooled heat exchange zone D may also be a separate new plate heat exchanger or core that receives the condensate or its steam-liquid mixture from the outlet of the plate heat exchange zone C. Through the plate wall, the condensate or vapor-liquid mixture on one side exchanges heat with the cold liquid on the other side to further absorb the heat enthalpy value in the condensate; or the subcooling heat exchange zone D uses a tubular heat exchanger for heat exchange, that is, the condensate or vapor-liquid mixture at the outlet of the plate heat exchange zone C enters the subcooling heat exchange zone D, and its condensate or vapor-liquid mixture enters the tube bundle or outside the tube bundle, and exchanges heat with the cold liquid through the tube bundle wall; or the subcooling heat exchange zone D, depending on the operating conditions and the design and layout of the heat exchanger, adopts one or more sections of plate heat exchange and another or more sections of tubular heat exchange.

5. A vapor-liquid tube sheet heat exchanger according to claim 1, 2, 3 or 4, characterized in that: A deep subcooling heat exchange zone E is further provided after the subcooling heat exchange zone D; the deep subcooling heat exchange zone E adopts a plate heat exchanger, a tube heat exchanger, or a combination of plate and tube heat exchangers; the condensed steam, or the steam-water mixture contained therein, flows out of the outlet of the subcooling heat exchange zone D and into the deep subcooling heat exchange zone E; when the deep subcooling heat exchange zone E uses a plate heat exchanger, the plate heat exchange component is an extension of the core of the deep subcooling heat exchange zone E, achieving further cooling of the steam-water mixture in zone E through wall heat exchange, turning it into condensate and then passing it through the condensate; when the deep subcooling heat exchange zone E uses a plate heat exchanger, it may be... In the D zone of the plate subcooling heat exchanger, the condensate at the outlet is separated into a new plate heat exchanger or core package. Through the plate walls, the condensate on one side exchanges heat with the cold liquid on the other side to further absorb the heat enthalpy value in the condensate. Alternatively, in the E zone of the deep subcooling heat exchanger, a tubular heat exchanger is used for heat exchange. That is, the condensate at the outlet of the subcooling heat exchanger D enters the deep subcooling heat exchanger E, and its condensate or steam-water mixture enters the tube bundle or outside the tube bundle, where it exchanges heat with the cold liquid through the tube bundle walls. Alternatively, depending on the operating conditions and the design and arrangement of the heat exchangers, one or more sections of the deep subcooling heat exchanger E may use plate heat exchangers, while another or more sections may use tubular heat exchangers.

6. A vapor-liquid tube sheet heat exchanger according to claim 5, characterized in that: Further, a condensate discharge zone F is set after the deep subcooling heat exchange zone E; the condensate discharge zone F has a condensate collection box, which is a separate box or part of the subcooling heat exchange zone D or the deep subcooling heat exchange zone E; a condensate discharge port is provided at the bottom of the box to facilitate the discharge of condensate out of the heat exchanger after the heat is released.

7. A vapor-liquid tube sheet heat exchanger according to claim 1, 2, 3 or 4, characterized in that: Between the steam inlet and outlet of the tubular heat exchanger in zone B, a steam distribution plate is further arranged. The steam distribution plate is arranged in the cross section in the direction of steam flow. The steam distribution plate has a porous structure, and the steam is redistributed through the pores to achieve a more uniform steam distribution after the steam distribution plate.

8. A vapor-liquid tube sheet heat exchanger according to claim 1, 2, 3 or 4, characterized in that: In the deep subcooling heat exchange zone E, along the steam flow direction, at the rear end of zone E, an inverted baffle is installed; the inverted baffle maintains a certain flow height with the bottom surface, so that the liquid or gas can gather upwards and stay for more time to be further condensed and subcooled.

9. A vapor-liquid tube sheet heat exchanger according to claim 1, 2, 3 or 4, characterized in that: Level gauges should be installed in the condensate discharge zone F, the subcooled heat exchange zone D, or the deep subcooled heat exchange zone E, especially in zone F, to facilitate the monitoring and control of the time, flow rate, temperature, etc. of the discharged condensate.

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