Phase change heat exchanger

Abstract

The invention discloses a phase change heat exchanger which comprises a shell, an inlet flow dividing partition plate, a cooling pipe, a convex lower partition plate set and a cooling pipe middle partition plate. The inlet flow dividing partition plate is transversely arranged at the inlet and is constructed to divide an inflow medium into two parts, the upper half part of the inflow medium serves as a condensed fluid path, and the lower half part of the inflow medium serves as a hot fluid mass transfer path; the front cooling pipe group and the rear cooling pipe group are forked by the front convex lower partition plate and the rear convex lower partition plate respectively to be dense and sparse from top to bottom, and each group of cooling pipes is also divided into an upper part and a lower part; the cooling pipe middle partition plate is located below the convex lower partition plate set and arranged in the mode of being orthogonal to the convex lower partition plate set. The bottom of the shell comprises a liquid collecting tank and an outlet; the liquid collecting tank is configured to collect condensed liquid from the cooling pipe; the outlet is used for discharging condensed liquid. The phase change heat exchanger is low in energy consumption and efficient in heat exchange, the condensation heat transfer coefficient is increased, and condensate can be cleaned in time.

Description

Technical Field

[0001] This application relates to the field of high-efficiency heat exchange technology, and in particular to a phase change heat exchanger. Background Technology

[0002] Fluoroplastic heat exchangers, with their advantages of corrosion resistance, high temperature resistance, high heat transfer coefficient, light weight, long service life, and low operating and maintenance costs, have been widely used in petroleum, chemical, pharmaceutical, textile, printing and dyeing, transportation, power, and military industries. The main problems with traditional fluoroplastic heat exchangers include: 1) Due to the orderly arrangement of multiple sets of cooling tubes inside the heat exchanger, the flow resistance is very high; 2) As the hot fluid is cooled, water vapor, soluble particles, gaseous condensable particles, soluble salts, etc., in the hot fluid will condense into liquid and adhere to the cooling pipes. Then, under the influence of gravity, they will fall to the bottom of the heat exchanger and be discharged. However, because the cooling pipes are arranged closely, the condensed liquid is prone to accumulate, which will seriously affect the heat exchange efficiency. 3) There will always be gaps between the cooling pipes and the walls of the cooler, especially at the bends of the cooling pipes. This will lead to uneven flow of heat fluid and further reduce heat exchange efficiency. Summary of the Invention

[0003] The purpose of this application is to provide a low-energy-consumption, high-efficiency phase change heat exchanger that can improve heating uniformity, reduce flow resistance, increase condensation heat transfer coefficient, and promptly remove condensate.

[0004] This application discloses a phase change heat exchanger, including: a shell, an inlet flow divider, cooling pipes, a convex lower baffle assembly, and a cooling pipe intermediate baffle; wherein, the convex lower baffle assembly includes a front convex lower baffle near the inlet and a rear convex lower baffle away from the inlet; along the flow direction of the inflow medium, the cooling pipes include a front cooling pipe assembly with a sparser flow pattern followed by a denser flow pattern and a rear cooling pipe assembly. The inlet diversion baffle is horizontally arranged at the inlet and is configured to divide the inflow medium into two parts: the upper part of the inflow medium serves as the condensate fluid path, and the lower part of the inflow medium serves as the heat fluid mass transfer path. The forward-convex lower partition and the rear-convex lower partition respectively separate the front cooling pipe group and the rear cooling pipe group, forming a denser to sparser structure from top to bottom, and also divide each cooling pipe group into upper and lower parts; The intermediate partition of the cooling pipe is located below the convex lower partition group and is arranged orthogonally to the convex lower partition group; The bottom of the housing includes a liquid collection tank and an outlet; the liquid collection tank is configured to collect condensed liquid from the cooling pipes; the outlet is used to discharge the condensed liquid.

[0005] In a preferred embodiment, the condensate fluid path is configured to flow through the cooling pipe section above the convex lower baffle; the heat transfer fluid path is configured to purge the surface of the convex lower baffle and flow through the cooling pipe section below the convex lower baffle.

[0006] In a preferred embodiment, the partition in the cooling tube is configured to form a serpentine flow field for the inflow medium of the heat transfer path.

[0007] In a preferred embodiment, the inlet diversion baffle has a chamfered angle.

[0008] In a preferred embodiment, the inlet diversion baffle has a diversion ratio for the inflow medium ranging from 7:3 to 8:2.

[0009] In a preferred embodiment, the convex lower baffle assembly forms a gap with the housing wall, the gap allowing condensate to flow to the bottom of the housing.

[0010] In a preferred embodiment, the inlet and outlet of the condenser tube are located at the top of the heat exchanger.

[0011] In a preferred embodiment, the forward-convex lower partition and the rearward-convex lower partition are each slightly conical with a pointed central apex.

[0012] This application has at least the following beneficial effects: 1. Cooling tubes arranged in a gradient of sparser front and denser back can reduce the resistance in the first half of the heat exchanger and increase the heat exchange capacity in the second half. 2. A lower baffle is installed on the lower section of the cooling pipe. On the one hand, this increases the spacing between the cooling pipes at the lower end, which is conducive to the flow of condensing fluid down. On the other hand, the convex lower baffle facilitates the flow of fluid from the cooling pipes to the liquid collection tank at the bottom of the baffle for discharge. 3. The lower baffle divides the cooling pipe into two parts to prevent all the condensate from flowing into the lower half of the cooling pipe, which would hinder the discharge of condensate and reduce the heat exchange area.

[0013] 4. The inlet diversion baffle separates heat and mass transfer. The upper gas flows through the upper half of the cooling pipe for sufficient heat exchange, while the lower gas blows directly onto the two lower baffles, which facilitates the flow of condensate on the lower baffles into the liquid collection tank for discharge.

[0014] 5. The partition plate in the middle of the cooling tube can create a serpentine flow field in the lower half of the cooling tube, lengthen the heat exchange path, make full use of the lower half of the cooling tube, and improve the heat exchange capacity. Attached Figure Description

[0015] The specification of this application contains numerous technical features distributed across various technical solutions. Listing all possible combinations of these technical features (i.e., technical solutions) would make the specification excessively lengthy. To avoid this problem, the various technical features disclosed in the above-described invention, the various technical features disclosed in the following embodiments and examples, and the various technical features disclosed in the accompanying drawings can be freely combined to form various new technical solutions (all of which should be considered as described in this specification), unless such a combination of technical features is technically infeasible. For example, one example discloses feature A+B+C, and another example discloses feature A+B+D+E. Features C and D are equivalent technical means that serve the same function, and technically only one needs to be used; they cannot be used simultaneously. Feature E can technically be combined with feature C. Therefore, the solution A+B+C+D should not be considered as described because it is technically infeasible, while the solution A+B+C+E should be considered as described.

[0016] Figure 1 This is a schematic diagram of a phase change heat exchanger according to this application, showing the heat exchanger portion without assembled cooling tubes; Figure 2 This is a schematic diagram of the front cooling pipe assembly according to this application; Figure 3 This is a schematic diagram of the aftercooler pipe assembly according to this application; Figure 4 This is a complete assembly schematic diagram of the phase change heat exchanger according to this application; Figure 5 This is a schematic diagram illustrating the flow field and heat transfer of the phase change heat exchanger according to this application; Explanation of reference numerals in the attached figures: 1-Export; 2-Liquid collection tank; 3-Inlet diversion baffle; 4-Forward convex lower baffle; 5-Rear convex lower baffle; 6-Cooling pipe intermediate baffle; 8 - Front cooling pipe assembly; 9 - Rear cooling pipe assembly. Detailed Implementation

[0017] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0018] the term As used in this article, "phase change heat exchanger" and "heat exchanger" can be used interchangeably, both referring to Shen's low-energy-consumption and high-efficiency phase change heat exchanger.

[0019] The following is a brief summary of some of the innovative aspects of the embodiments of this application: The phase change heat exchanger of this application, such as Figure 1 As shown, it includes: a housing, an inlet diversion baffle 3, cooling pipes, a convex lower baffle assembly, and a cooling pipe intermediate baffle 6. The convex lower baffle assembly includes a front convex lower baffle 4 near the inlet and a rear convex lower baffle 5 away from the inlet. The cooling pipes include a front cooling pipe assembly 8 and a rear cooling pipe assembly 9, which are respectively installed and adapted to the front convex lower baffle 4 and the rear convex lower baffle 5.

[0020] A convex lower baffle is laterally positioned at the inlet on the side of the casing and has a certain bevel angle. The function of this baffle is to divide the inlet hot fluid (e.g., flue gas) into two streams, and the bevel angle facilitates purging of part of the split gas. The hot fluid, divided into two parts by the inlet baffle 3, flows through cooling pipes arranged in a gradient of sparser and denser sections. These two parts of the hot fluid follow the following two paths: Heat transfer path: The heat transfer path is mainly the lower portion of the heat flow diverted by the inlet diversion baffle 3, which performs a purging action. This includes purging the condensate on the forward-convex lower baffle 4 and the rearward-convex lower baffle 5, and the front cooling pipe assembly 8 and the rear cooling pipe assembly 9 flowing below the forward-convex lower baffle 4 and the rearward-convex lower baffle 5. This portion of the heat flow bypasses the intermediate baffle 6 of the cooling pipes, flows in a serpentine pattern, and finally flows out from the outlet opposite the inlet.

[0021] Condensation fluid path: The main mass transfer path is the hot fluid diverted by the inlet diverter 3. The fluid condensed on the cooling pipes will flow along the condenser pipes to the surfaces of the forward-convex lower baffle 4 and the rearward-convex lower baffle 5, and then be blown down into the liquid collection tank 2 by the hot fluid in the mass transfer path. In the hot fluid mass transfer path, the hot fluid flowing through the cooling pipes below the forward-convex lower baffle 4 and the rearward-convex lower baffle 5 is cooled, falls along the cooling pipes into the liquid collection tank 2, and finally flows out from the liquid outlet 1.

[0022] The convex lower baffle assembly includes a front convex lower baffle 4 and a rear convex lower baffle 5, which are horizontally arranged inside the shell and located vertically below the inlet diversion baffle at a certain distance. The front convex lower baffle 4 houses the front cooling pipe assembly 8, and the rear convex lower baffle 5 houses the rear cooling pipe assembly 9. The front convex lower baffle 4 and the rear convex lower baffle 5 spread each cooling pipe assembly outwards, forming a denser-to-sparser arrangement from top to bottom. This dense-to-sparse arrangement aims to prevent condensate from sticking together and causing large-area heat exchange pipe failure. Simultaneously, the convex lower baffle assembly divides each cooling pipe assembly into upper and lower sections. The front convex lower baffle 4 and the rear convex lower baffle 5 have gaps with the shell wall to facilitate drainage; both plates are slightly conical with a pointed central apex to allow condensate to drain along the inclined angle, condensate to slide off and be collected, and then swept into a liquid collection tank by hot fluid.

[0023] The intermediate partition 6 of the cooling tubes is located below the convex lower partition assembly and is arranged orthogonally to the convex lower partition assembly. Below the convex lower partition assembly, the hot fluid from the cooling tubes flows through the intermediate partition 6 in a serpentine flow field. The main function of the intermediate partition 6 is to create a flow around the heat exchanger shell, allowing the hot fluid (e.g., flue gas) to stay longer inside the heat exchanger for more efficient heat exchange. The hot fluid in the mass transfer path bypasses the intermediate partition 6 and enters the area of ​​the post-cooling tube assembly 9, forming a serpentine flow pattern to further clean the accumulated liquid in the lower half of the tube section below the intermediate partition 6.

[0024] The cooling pipe assembly includes a front cooling pipe group 8 and a rear cooling pipe group 9, which are respectively fitted to the front convex lower baffle 4 and the rear convex lower baffle 5. The rear cooling pipe group 9 contains more cooling pipes than the front cooling pipe group 8. This arrangement, with a wider front and a denser rear along the flow direction, ensures that the rear cooling pipe group 9 is exposed to the hot fluid (flue gas). The front cooling pipe group 8 and the rear cooling pipe group 9 are not interconnected, facilitating modular production and assembly.

[0025] The two diverted hot fluids eventually merge and flow out at the heat exchanger outlet. Because some condensable gases in the hot fluid condense and flow downwards along the cooling pipes, the liquid adhering to the surface of the cooling pipes above the convex lower baffle assembly eventually collects on the surface of the lower baffle assembly and falls into the liquid collection tank after being purged by the hot fluid. For the cooling pipes below the convex lower baffle assembly, the liquid adhering to the surface falls directly into the liquid collection tank. Both portions of condensate are ultimately discharged from the liquid outlet.

[0026] To better understand the technical solution of this application, a specific example is provided below. The details listed in this example are mainly for ease of understanding and are not intended to limit the scope of protection of this application.

[0027] The phase change heat exchanger according to this application condenses the flue gas. The inlet diversion baffle 3 is located at the inlet, which can distribute the inlet flue gas in a 7:3 or 8:2 ratio. The large stream of fluid impacts the heat exchange tubes on the upper part of the baffle, achieving condensation; the small stream of fluid is used to purge the liquid accumulated on the convex lower baffle assembly. The inlet diversion baffle 3 mainly serves as a guide, and it maintains a certain distance from the convex lower baffle assembly in the vertical direction. The purpose is to ensure that both the front convex lower baffle 4 and the rear convex lower baffle 5 are purged, thereby achieving the core invention point of this application: the heat exchange effect of the upper tube bundle is good (the liquid accumulates more and more along the tube wall from top to bottom, and the heat exchange effect becomes worse and worse. By using the front convex lower baffle 4 and the rear convex lower baffle 5, the tube section with good heat exchange effect is placed in the upper part, and the liquid in the lower part is cleaned by the purging flue gas).

[0028] Based on the analysis of flow field and heat transfer, an optimized design is proposed. By setting a half-baffle, the flue gas is changed from flowing horizontally across the dense tube bundle to flowing around the tube bundle arrangement direction, so that the flow resistance is about 70% of the original scheme, thereby achieving the effect of energy saving (reducing the work done by the fan).

[0029] It should be noted that in this patent application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this patent application, if it refers to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0030] This specification includes combinations of various embodiments described herein. Individual references to “one embodiment” or a particular embodiment, etc., do not necessarily refer to the same embodiment; however, these embodiments are not mutually exclusive unless indicated to be mutually exclusive or are readily apparent to those skilled in the art. It should be noted that the word “or” is used in a non-exclusive sense throughout this specification unless the context explicitly indicates or requires it.

[0031] All documents mentioned in this application are considered to be incorporated in their entirety into the disclosure of this application so that they can serve as a basis for modifications if necessary. Furthermore, it should be understood that after reading the foregoing disclosure of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A phase change heat exchanger, characterized in that, include: The system comprises a housing, an inlet diversion baffle, cooling pipes, a convex lower baffle assembly, and a cooling pipe intermediate baffle; wherein the convex lower baffle assembly includes a front convex lower baffle near the inlet and a rear convex lower baffle away from the inlet; along the flow direction of the inflow medium, the cooling pipes include a front cooling pipe assembly that is initially sparse and then becomes dense, and a rear cooling pipe assembly. The inlet diversion baffle is horizontally arranged at the inlet and is configured to divide the inflow medium into two parts: the upper part of the inflow medium serves as the condensate fluid path, and the lower part of the inflow medium serves as the heat fluid mass transfer path. The forward-convex lower partition and the rear-convex lower partition respectively separate the front cooling pipe group and the rear cooling pipe group, forming a denser to sparser structure from top to bottom, and also divide each cooling pipe group into upper and lower parts; The intermediate partition of the cooling pipe is located below the convex lower partition group and is arranged orthogonally to the convex lower partition group; The bottom of the housing includes a liquid collection tank and an outlet; the liquid collection tank is configured to collect condensed liquid from the cooling pipes; the outlet is used to discharge the condensed liquid.

2. The phase change heat exchanger as described in claim 1, characterized in that, The condensate flow path is configured to flow through the cooling pipe section above the convex lower baffle; the heat transfer flow path is configured to purge the surface of the convex lower baffle and flow through the cooling pipe section below the convex lower baffle.

3. The phase change heat exchanger as described in claim 1, characterized in that, The partition plate in the cooling pipe is configured to form a serpentine flow field for the inflow medium of the heat transfer path.

4. The phase change heat exchanger as described in claim 1, characterized in that, The inlet diversion baffle has a beveled angle.

5. The phase change heat exchanger as described in claim 1, characterized in that, The inlet diversion baffle has a diversion ratio for the inflow medium ranging from 7:3 to 8:

2.

6. The phase change heat exchanger as described in claim 1, characterized in that, The convex lower partition plate assembly forms a gap with the shell wall, and the gap allows the condensate fluid to flow to the bottom of the shell.

7. The phase change heat exchanger as described in claim 1, characterized in that, The inlet and outlet of the condenser tube are located at the top of the heat exchanger.

8. The phase change heat exchanger as claimed in claim 1, characterized in that, The forward-convex lower partition and the rear-convex lower partition are both slightly conical with a pointed central apex.

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