An out-of-tube evaporation wound tube type steam generator

Abstract

The utility model relates to the field of steam generator, in order to solve the problem of the existing steam generator's land area is larger, the problem of high manufacturing cost and when the steam body and liquid density difference is small, difficult to effectively realize the problem of gas-liquid separation, provide a kind of pipe outside evaporation winding pipe type steam generator, it include: first shell layer, heat source pipe, vapor-liquid separator, second shell layer, annular sealing plate, liquid level measuring cylinder;Heat source pipe is located inside first shell layer;Vapor-liquid separator is communicated with the inner chamber of first shell layer;Annular flow channel is formed between second shell layer and first shell layer, and the liquid outlet of vapor-liquid separator is communicated with annular flow channel;Annular sealing plate is located at the bottom end of annular flow channel;One end of the liquid level measuring cylinder is communicated with the annular flow channel. The utility model can effectively realize the direct current evaporation of liquid, and realize the convenience of operation control, and the change of liquid level in monitoring liquid level measuring cylinder is directly judged to intuitively judge the heat supply condition of heating medium, and provides operation guidance for system regulation and control.

Description

Technical Field

[0001] This utility model relates to the field of steam generators, and more specifically, to an external evaporation wound tube type steam generator. Background Technology

[0002] Spiral wound tube heat exchangers are a new type of high-efficiency heat exchanger developed in the last two decades. They are widely used in heating or cooling processes in industries such as coal chemical, petrochemical, large-scale fertilizer, natural gas processing, and comprehensive energy utilization. The main advantages of this type of heat exchanger are: 1) compact structure; 2) high heat transfer efficiency, enabling heat transfer with large temperature rise and small temperature difference; 3) low temperature stress between the heat exchange tubes and the tube sheet; and 4) ability to achieve simultaneous heat exchange by multiple streams (≥2 streams). Using spiral wound tube heat exchangers for liquid direct-flow evaporation can reduce equipment size and weight, facilitate site layout, and save equipment costs.

[0003] Existing liquid evaporation structures are mainly based on non-DC evaporation and DC evaporation.

[0004] For non-direct-flow evaporation, the evaporation structure is a circulating evaporation structure, such as the common shell-and-tube waste heat boiler. This system consists of a heat exchanger, a steam drum (vapor-liquid separator), risers, and downcomers, forming the steam generation system. The heat exchanger heats the liquid for incomplete evaporation, producing a two-phase vapor-liquid fluid that enters the steam drum through the risers for vapor-liquid separation. The separated saturated liquid, along with makeup liquid, enters the heat exchanger through the downcomers for circulating heating and evaporation. During the heat exchange process, the convective heat exchange between the medium to be evaporated and the heating medium improves the heat exchange efficiency. Its disadvantages are: it is difficult to achieve liquid evaporation with a single device; it requires a large footprint and has high investment costs; and when the density difference between the gas and liquid is small, such as in the evaporation of high-pressure liquid carbon dioxide, gas-liquid separation is difficult to achieve.

[0005] For direct-flow evaporation structures, such as the common autoclave evaporator, liquid evaporation is carried out in a large-volume pool. Although a single device can complete the process, external evaporation requires a large liquid surface space and volume, which in turn requires a large shell volume. When the operating pressure of the evaporating liquid is high, the pressure-bearing shell wall is thicker, resulting in a large size, heavy weight, large space occupation, and high equipment cost. When the density difference between gas and liquid is small, it is also difficult to achieve gas-liquid separation. Utility Model Content

[0006] The purpose of this invention is to provide an external evaporation wound tube steam generator, which solves the problems of large footprint and high manufacturing cost of existing steam generators, as well as the difficulty in effectively achieving gas-liquid separation when the density difference between gas and liquid is small.

[0007] The embodiments of this utility model are achieved through the following technical solutions:

[0008] An external evaporation wound tube type steam generator includes: a first shell, a heat source tube, a vapor-liquid separator, a second shell, an annular sealing plate, and a liquid level measuring cylinder; the first shell has an outlet and an inlet for the medium to be evaporated; the heat source tube is located inside the first shell, and a flow channel for the medium to be evaporated is formed between the outer wall of the heat source tube and the inner wall of the first shell; the vapor-liquid separator is connected to the inner cavity of the first shell; the first shell is located inside the second shell, and an annular flow channel is formed between the second shell and the first shell, with the liquid outlet of the vapor-liquid separator connected to the annular flow channel; the annular sealing plate is located at the bottom end of the annular flow channel, with the inner annular wall of the annular sealing plate connected to the outer wall of the first shell, and the outer annular wall of the annular sealing plate connected to the inner wall of the second shell; one end of the liquid level measuring cylinder is connected to the annular flow channel.

[0009] Preferably, the second shell includes: an upper tube box and a main shell, the upper tube box is provided with a heating medium inlet, the upper tube box is connected to the heat source pipe; the bottom end of the upper tube box is connected to the top end of the main shell, and the main shell is provided with an outlet for the medium to be evaporated and an inlet for the medium to be evaporated.

[0010] Preferably, the outer casing further includes: a lower tube box, the lower tube box having a heating medium outlet, the top end of the lower tube box being connected to the bottom end of the main casing; the lower tube box being connected to the heat source pipe.

[0011] Preferably, the upper side wall of the liquid level measuring cylinder is in communication with the annular flow channel.

[0012] Preferably, the sidewall of the annular flow channel is provided with a liquid return port, which is located near the bottom end of the annular flow channel.

[0013] Preferably, the steam generator further includes a central tube disposed within the first shell layer, and the heat source tube spirally wound around the periphery of the central tube.

[0014] Preferably, there are multiple heat source pipes, which are arranged in an alternating parallel spiral around the periphery of the central pipe.

[0015] Preferably, the steam generator includes an upper tube sheet and a lower tube sheet, wherein the upper tube sheet is disposed on the side of the upper tube box near the main housing; the lower tube sheet is disposed on the side of the lower tube box near the main housing; and the central tube is disposed between the upper tube sheet and the lower tube sheet.

[0016] This utility model has at least the following beneficial effects:

[0017] This invention effectively achieves direct-flow evaporation of liquids and facilitates convenient operation control. When the heating medium provides insufficient heat, and the gas produced during evaporation carries liquid, vapor-liquid separation can be achieved. The separated liquid is led out to an external liquid level measuring cylinder through an annular flow channel between the first and second shells. When the heating medium provides excessive heat, the liquid completely evaporates, and the liquid level in the measuring cylinder remains unchanged. When the heating medium provides insufficient heat, the liquid partially evaporates, and the liquid level in the measuring cylinder rises. By monitoring the changes in the liquid level in the measuring cylinder, the heat supply of the heating medium can be intuitively judged, providing operational guidance for system control. Because the structure of this invention effectively achieves direct-flow evaporation of liquids, a large-volume liquid tank is not required, reducing the equipment size. Furthermore, the direct-flow evaporation method combined with the control of the heating medium ensures complete evaporation of the liquid, reducing the load on the vapor-liquid separator. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the first structure of an externally evaporating wound tube steam generator;

[0020] Figure 2 This is a schematic diagram of the heat transfer structure;

[0021] Figure 3 This is a schematic diagram of the second structure of an externally evaporating wound tube steam generator.

[0022] Icons: 1-First shell, 101-Outlet of medium to be evaporated, 102-Inlet of medium to be evaporated, 2-Heat source pipe, 3-Vacuum-liquid separator, 4-Second shell, 401-Upper tube box, 4011-Heating medium inlet, 402-Main shell, 403-Lower tube box, 4031-Heating medium outlet, 5-Annular flow channel, 501-Liquid reflux port, 6-Annular sealing plate, 7-Liquid level measuring cylinder, 8-Central tube, 9-Upper tube sheet, 10-Lower tube sheet. Detailed Implementation

[0023] To make the objectives, methods, and advantages of the embodiments of this utility model clearer, the methods in the embodiments of this utility model will be clearly and completely described. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0024] Example 1: As Figure 1-3As shown, an external evaporation wound tube type steam generator includes: a first shell layer 1, a heat source tube 2, a vapor-liquid separator 3, a second shell layer 4, an annular sealing plate 6, and a liquid level measuring cylinder 7; the first shell layer 1 is provided with an outlet 101 and an inlet 102 for the medium to be evaporated; the heat source tube 2 is disposed inside the first shell layer 1, and a flow channel for the medium to be evaporated is formed between the outer wall of the heat source tube 2 and the inner wall of the first shell layer 1; the vapor-liquid separator 3 is connected to the inner cavity of the first shell layer 1; the first shell layer 1 is located inside the second shell layer 4, and an annular flow channel 5 is formed between the second shell layer 4 and the first shell layer 1, and the liquid outlet of the vapor-liquid separator 3 is connected to the annular flow channel 5; the annular sealing plate 6 is disposed at the bottom end of the annular flow channel 5, the inner annular wall of the annular sealing plate 6 is connected to the outer wall of the first shell layer 1, and the outer annular wall of the annular sealing plate 6 is connected to the inner wall of the second shell layer 4; one end of the liquid level measuring cylinder 7 is connected to the annular flow channel 5.

[0025] In practical implementation, the typical application scenario of the steam generator provided in this embodiment is the evaporation of liquid carbon dioxide in a novel carbon dioxide energy storage system. For example, carbon dioxide power generation and storage technology, officially known as supercritical carbon dioxide (S-CO2) energy storage and power generation technology. This technology cleverly utilizes the highly efficient energy conversion performance of carbon dioxide in a supercritical state (temperature above 31.1℃, pressure above 7.38MPa, possessing both gas and liquid characteristics) to achieve bidirectional storage and release of electrical energy and thermal / pressure energy, making it a highly innovative new energy storage technology. Its core lies in organically combining the compression and expansion processes of carbon dioxide with thermodynamic cycles through a closed-loop system to achieve efficient energy storage and power generation, and is considered one of the revolutionary technologies in the next generation of high-efficiency energy storage and power generation.

[0026] Energy storage stage: Carbon dioxide (or recovered industrial CO2) at ambient temperature and pressure is pressurized to a supercritical state (e.g., pressure reaches 20-30 MPa, temperature approximately 100-300℃) by a compressor. During this process, the heat generated by compression is collected by a heat exchanger and stored in a high-temperature thermal storage device (such as molten salt or solid thermal storage materials). The compressed supercritical CO2 enters a cryogenic storage tank (temperature approximately 50-100℃, under high pressure), while the heat of compression is stored in a high-temperature thermal storage system, thus achieving dual storage of "thermal energy + pressure energy".

[0027] Energy release stage: Low-temperature, high-pressure CO2 flows out of the storage tank and first absorbs high-temperature heat (temperature can be raised to 500-700℃) from the heat exchanger, transforming into high-temperature supercritical CO2. The high-temperature, high-pressure CO2 drives the turbine generator to expand and do work, driving the impeller to generate electricity. Afterwards, the CO2 is cooled and depressurized to return to its initial state, entering the next cycle.

[0028] As can be seen from the above, CO2 is always under high pressure during the energy release phase. If a circulating evaporation structure is used, the pressure resistance requirements of various parts of the equipment are high. Therefore, using direct current evaporation can not only reduce the size of the equipment, but also reduce the pressure resistance requirements of certain parts of the equipment.

[0029] To ensure effective direct current evaporation, this embodiment includes an annular flow channel 5 and a liquid level measuring cylinder 7. When the heating medium provides insufficient heat, and the gas produced during evaporation carries liquid, vapor-liquid separation can be achieved. The separated liquid is led out through the annular flow channel 5 between the first shell layer 1 and the second shell layer 4 to the external liquid level measuring cylinder 7. When the heating medium provides excessive heat, the liquid completely evaporates, and the liquid level in the liquid level measuring cylinder 7 does not rise. When the heating medium provides insufficient heat, the liquid will partially evaporate, and the liquid level in the liquid level measuring cylinder 7 will rise. Thus, by monitoring the changes in the liquid level in the liquid level measuring cylinder 7, the heat supply of the heating medium can be intuitively judged, providing operational guidance for system control.

[0030] As an example, a level gauge can be installed in the level measuring cylinder 7. The heating medium is delivered via a variable frequency pump, and the delivery parameters of the heating medium are regulated through an existing DCS control system. As an example, after the level gauge transmits the detected level data to the DCS control system, the analysis module analyzes and judges the data, and then controls the speed of the variable frequency pump. As an example, DC evaporation can also be regulated by adjusting the temperature of the heating medium.

[0031] During the heat exchange process, the heating medium enters the heat source pipe 2 through the heating medium inlet 4011, then flows downwards and exits through the heating medium outlet 4031. The medium to be evaporated, such as liquid CO2, enters the space between the inner wall of the first shell 1 and the outer wall of the heat source pipe 2 from below the first shell 1, flows upwards and absorbs heat from the heating medium in the heat source pipe 2. After undergoing preheating, saturation, and a gradual superheating process where the cross-sectional vapor content rises from 0 to 100%, the liquid enters the vapor-liquid separator 3. When incomplete evaporation occurs, the liquid separated by the vapor-liquid separator 3 falls back into the annular flow channel 5 between the first shell 1 and the second shell 4, and is introduced into the liquid measuring cylinder through the annular flow channel 5. The liquid level can be visually reflected by the level gauge installed on the liquid level measuring port of the liquid level measuring cylinder 7.

[0032] Since the steam generator provided in this embodiment can effectively achieve direct-flow evaporation of liquid, a large-volume liquid tank is not required, and the equipment size can be reduced. In addition, the direct-flow evaporation method combined with the regulation of the heating medium can ensure complete evaporation of liquid and reduce the load on the vapor-liquid separator 3.

[0033] The heating medium can be high-temperature molten salt, or high-temperature gaseous medium, such as high-temperature air, flue gas, chemical waste heat gas and other media.

[0034] In this embodiment, each interface or pipe opening can be connected by flange, welding, or other suitable connection methods. Components can be equipped with safety accessories such as temperature measurement, pressure measurement, and safety relief devices, as well as welding accessories such as supports and lifting lugs, as needed.

[0035] Example 2: As Figure 1-2 As shown, in this embodiment, the second shell layer 4 includes: an upper tube box 401 and a main shell 402. The upper tube box 401 is provided with a heating medium inlet 4011 and is connected to the heat source pipe 2. The bottom end of the upper tube box 401 is connected to the top end of the main shell 402, and the main shell 402 is provided with an outlet 101 and an inlet 102 for the medium to be evaporated. The outer shell also includes: a lower tube box 403. The lower tube box 403 is provided with a heating medium outlet 4031 and the top end of the lower tube box 403 is connected to the bottom end of the main shell 402. The lower tube box 403 is connected to the heat source pipe 2.

[0036] In practice, both the upper tube box 401 and the lower tube box 403 can be pressure-bearing shells. The upper and lower ends of the heat source pipe 2 are connected to the upper tube box 401 and the lower tube box 403, respectively. The heating medium enters the upper tube box 401 from the heating medium 1 at the top of the equipment, then flows downward into the heat source pipe 2, gradually releasing heat and being cooled before entering the lower tube box 403, and finally flowing out through the heating medium outlet 4031.

[0037] Example 3: As Figure 1 As shown, in this embodiment, the upper sidewall of the liquid level measuring cylinder 7 is connected to the annular flow channel 5.

[0038] In the specific implementation process, the end of the liquid level measuring cylinder 7 near the bottom wall is connected to the side wall of the second shell layer 4 near the annular flow channel 5, and the end of the liquid level measuring cylinder 7 away from the bottom wall is also connected to the annular flow channel 5. This can balance the pressure inside the liquid level measuring cylinder 7 and the annular flow channel 5, ensuring that the liquid level height inside the liquid level measuring cylinder 7 is consistent with the liquid level height inside the annular flow channel 5.

[0039] Example 4: Figure 1 As shown, in this embodiment, the side wall of the annular flow channel 5 is provided with a liquid return port 501, which is located near the bottom end of the annular flow channel 5.

[0040] In the specific implementation process, a valve can be installed after the outer pipe body of the liquid return port 501 of the annular flow channel 5. The liquid that has not been completely evaporated can be returned to the inlet 102 of the medium to be evaporated or the first shell layer 1 through the liquid return port 501 for secondary evaporation.

[0041] Example 5: Figure 1-2As shown, in this embodiment, the steam generator further includes a central tube 8, which is disposed within the first shell layer 1, and the heat source tube 2 is spirally wound around the periphery of the central tube 8.

[0042] In the specific implementation process Figure 1-2 The structure of the heat source tube 2 is not shown; it can be made of the same material as heat exchange tubes in existing technologies. To increase the heat transfer between the medium to be evaporated and the heating medium, in this embodiment, the heat source tube 2 can be spirally wound around the outer periphery of the central tube 8, similar to a spring. A gap may exist between the heat source tube 2 and the central tube 8 to increase the heat transfer area between the medium to be evaporated and the heat source tube 2. Through the spirally wound heat source tube 2, efficient heat transfer is achieved, enabling not only direct-flow evaporation of liquids but also saving more than 50% of space and more than 40% of equipment costs.

[0043] Example 6: As Figure 3 As shown, in this embodiment, there are multiple heat source pipes 2, and the multiple heat source pipes 2 are spirally wound around the periphery of the central pipe 8 in an alternating and parallel manner.

[0044] In practice, multiple heat source pipes 2 can be used. Multiple heat source pipes can flow through each other, allowing for simultaneous heating of the shell-side liquid using multiple heat source pipes for direct-flow evaporation. Each heat source pipe 2 can be supplied with the same heating medium or different heating media.

[0045] As an example, each heat source pipe 2 can recover heat from multiple waste gases by passing through different waste gases.

[0046] As an example, since the temperature of the heating medium in each heat source pipe 2 is not necessarily the same, if each heat source pipe 2 is arranged in a ring around the central pipe 8, the heat exchange effect at each circumferential position will be different. Therefore, in order to ensure heat exchange uniformity, each heat source pipe 2 can be arranged in an alternating manner around the central pipe 8.

[0047] Example 7: As Figure 1-2 As shown, in this embodiment, the steam generator includes: an upper tube sheet 9 and a lower tube sheet 10. The upper tube sheet 9 is provided on the side of the upper tube box 401 near the main housing 402; the lower tube sheet 10 is provided on the side of the lower tube box 403 near the main housing 402; and the central tube 8 is located between the upper tube sheet 9 and the lower tube sheet 10.

[0048] In the specific implementation process, after the second shell layer 4 is equipped with tubes corresponding to the outlet 101 and inlet 102 of the medium to be evaporated, the end of the tube away from the second shell layer 4 passes through the second shell layer 4, thereby realizing the medium to be evaporated being sent into the second shell layer 4 from the outside and being output from the second shell layer 4 to the outside of the equipment. The outlet 101 of the medium to be evaporated is located below the upper tube sheet 9, and the inlet 102 of the medium to be evaporated is located below the lower tube sheet 10. The central tube 8 and the heat source tube 2 can be installed by connecting to the upper tube sheet 9 and the lower tube sheet 10. After the upper tube sheet 9 and the lower tube sheet 10 are provided with through holes, the heat source tube 2 can be connected to the two tube boxes. The upper tube sheet 9 and the lower tube sheet 10 can separate the two tube boxes from the flow channel of the medium to be evaporated, preventing the medium to be evaporated from escaping from the upper tube box 401 after absorbing heat.

[0049] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A type of steam generator with external evaporation and winding tubes, characterized in that, include: The first shell layer (1) is provided with an outlet (101) for the medium to be evaporated and an inlet (102) for the medium to be evaporated; Heat source pipe (2), the heat source pipe (2) is disposed inside the first shell layer (1), and the outer wall of the heat source pipe (2) and the inner wall of the first shell layer (1) form a flow channel for the medium to be evaporated; A vapor-liquid separator (3) is connected to the inner cavity of the first shell layer (1); The second shell (4) is located inside the first shell (1), and an annular flow channel (5) is formed between the second shell (4) and the first shell (1). The liquid outlet of the vapor-liquid separator (3) is connected to the annular flow channel (5). An annular sealing plate (6) is provided at the bottom end of the annular flow channel (5). The inner ring wall of the annular sealing plate (6) is connected to the outer wall of the first shell layer (1), and the outer ring wall of the annular sealing plate (6) is connected to the inner wall of the second shell layer (4). A liquid level measuring cylinder (7) is provided, one end of which is connected to the annular flow channel (5).

2. The external evaporation wound tube steam generator according to claim 1, characterized in that, The second shell (4) includes: Upper pipe box (401), the upper pipe box (401) is provided with a heating medium inlet (4011), the upper pipe box (401) is connected to the heat source pipe (2); The main housing (402) has the bottom end of the upper pipe box (401) connected to the top end of the main housing (402), and the main housing (402) is provided with the outlet (101) of the medium to be evaporated and the inlet (102) of the medium to be evaporated.

3. The external evaporation wound tube steam generator according to claim 1, characterized in that, The casing also includes: The lower tube box (403) is provided with a heating medium outlet (4031). The top of the lower tube box (403) is connected to the bottom of the main shell (402). The lower tube box (403) is connected to the heat source pipe (2).

4. The external evaporation wound tube steam generator according to claim 1, characterized in that, The upper side wall of the liquid level measuring cylinder (7) is connected to the annular flow channel (5).

5. The external evaporation wound tube steam generator according to claim 1, characterized in that, The annular flow channel (5) has a liquid return port (501) on its side wall, and the liquid return port (501) is located near the bottom end of the annular flow channel (5).

6. The external evaporation wound tube steam generator according to any one of claims 1-5, characterized in that, include: The central tube (8) is located inside the first shell (1), and the heat source tube (2) is spirally wound around the periphery of the central tube (8).

7. The external evaporation wound tube steam generator according to claim 6, characterized in that, The heat source pipe (2) is provided in multiple ways, and the multiple heat source pipes (2) are spirally wound around the periphery of the central pipe (8) in an alternating parallel manner.

8. The external evaporation wound tube steam generator according to claim 7, characterized in that, include: The upper tube sheet (9) is provided on the side of the upper tube box (401) near the main housing (402); The lower tube sheet (10) is provided on the side of the lower tube box (403) near the main housing (402); The central tube (8) is located between the upper tube sheet (9) and the lower tube sheet (10).

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