An evaporator

Abstract

The application discloses an evaporator, which comprises a boiling chamber, a heating chamber and a liquid discharge chamber arranged in sequence from top to bottom, wherein an upper tube plate structure is arranged between the boiling chamber and the heating chamber, and a lower tube plate structure is arranged between the heating chamber and the liquid discharge chamber; a plurality of silicon carbide tubes are arranged in the heating chamber and each extends in the up-down direction; the upper end of each silicon carbide tube is sealed through the upper tube plate structure and communicates with the boiling chamber; the lower end of each silicon carbide tube is sealed through the lower tube plate structure and communicates with the liquid discharge chamber; a heat exchange space is formed in the space outside the silicon carbide tubes in the heating chamber, the side of the heating chamber is provided with a heat transfer medium inlet and a heat transfer medium outlet which communicate with the heat exchange space; and the volume of the boiling chamber is greater than the total volume of the silicon carbide tubes in the heating chamber. The application comprehensively applies the characteristics of silicon carbide, and through the arrangement of the boiling chamber, the evaporated liquid of the silicon carbide tubes is lifted to the boiling chamber, and then the boiling state is realized after the pressure reduction, thereby realizing integrated high-efficiency evaporation.

Description

Technical Field

[0001] This invention relates to the field of evaporation equipment technology, and more specifically to an evaporator. Background Technology

[0002] With the expansion of applications in the semiconductor industry, corrosion-resistant, high-temperature-resistant, and high-efficiency evaporators have become a demand in new fields. On May 31, 2022, the applicant filed a utility model patent for a silicon carbide falling film evaporator, which uses silicon carbide tubes made of silicon carbide material to improve the corrosion resistance of the evaporator.

[0003] Silicon carbide has a thermal conductivity almost equivalent to that of commonly used graphite tubes, and is far superior to that of other materials. It has twice the thermal conductivity of tantalum and five times that of stainless steel, resulting in higher heat exchange efficiency in heat exchangers. Furthermore, silicon carbide is currently the hardest high-performance material available for heat exchange tubes, exhibiting exceptional wear resistance and complete impermeability even under extreme temperatures and pressures, allowing for high-speed media flow with high thermal efficiency.

[0004] Therefore, based on the properties of silicon carbide, the applicant has further developed and proposed an evaporator with high pressure resistance, high temperature resistance, and strong corrosion resistance. Summary of the Invention

[0005] The purpose of this invention is to provide an evaporator with high pressure resistance, high temperature resistance, and strong corrosion resistance, achieving efficient integrated evaporation.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An evaporator includes a boiling chamber, a heating chamber, and a draining chamber arranged sequentially from top to bottom. An upper tube sheet structure is provided between the boiling chamber and the heating chamber, and a lower tube sheet structure is provided between the heating chamber and the draining chamber. Multiple silicon carbide tubes are arranged in the heating chamber, each extending vertically; the upper end of the silicon carbide tube passes through the upper tube sheet structure and is connected to the boiling chamber; the lower end of the silicon carbide tube passes through the lower tube sheet structure and is connected to the drain chamber. The space outside the silicon carbide tube is formed in the heating chamber, and the side of the heating chamber is provided with a heat transfer medium inlet and a heat transfer medium outlet that are connected to the heat transfer space. The volume of the boiling chamber is greater than the total volume of the silicon carbide tubes in the heating chamber. The boiling chamber is equipped with a liquid inlet and an exhaust outlet.

[0007] Furthermore, the volume of the boiling chamber is 2-3 times the total volume of the silicon carbide tubes in the heating chamber.

[0008] Furthermore, the liquid inlet is located on the side of the boiling chamber, and the exhaust port is located on the top of the boiling chamber. The space between the liquid inlet and the exhaust port is more than 1 / 3 of the volume of the boiling chamber.

[0009] Furthermore, the upper tube sheet structure includes a first upper tube sheet, a reinforcing plate, and a second upper tube sheet arranged sequentially from top to bottom. The first upper tube sheet, the reinforcing plate, and the second upper tube sheet are clamped and fixed between the boiling chamber and the heating chamber, and the first upper tube sheet, the reinforcing plate, and the second upper tube sheet are respectively provided with sealing devices between each other. The first upper tube sheet is provided with first upper distribution holes corresponding to the silicon carbide tubes, and the second upper tube sheet is provided with first lower distribution holes corresponding to the silicon carbide tubes. The upper end of the silicon carbide tube passes through the first lower distribution hole and the first upper distribution hole, and a first lower sealing structure is provided between the silicon carbide tube and the first lower distribution hole, and a first upper sealing structure is provided between the silicon carbide tube and the first upper distribution hole, thereby forming a double-layer sealing structure.

[0010] Furthermore, the first upper tube sheet is made of PTFE, and the second upper tube sheet is made of carbon steel.

[0011] Furthermore, the silicon carbide tube is fitted with a PTFE gasket, a perfluoroether O-ring, a PTFE gasket, a perfluoroether O-ring, and a perfluoroether O-ring in sequence from top to bottom at the first upper distribution hole position, forming a first upper sealing structure; The silicon carbide tube is fitted with a PTFE gasket, a perfluoroether O-ring, a PTFE gasket, a perfluoroether O-ring, and a perfluoroether O-ring in sequence from top to bottom at the first lower distribution hole position, forming a first lower sealing structure.

[0012] Furthermore, a support ring is provided between the reinforcing plate and the second upper tube plate, and a leakage port is provided on the support ring.

[0013] Furthermore, the lower tube sheet structure and the upper tube sheet structure are arranged symmetrically.

[0014] Furthermore, the bottom of the drain chamber is provided with a drain port; the side of the boiling chamber is also provided with a circulating liquid port.

[0015] Furthermore, the heat transfer medium inlet is connected to a steam source.

[0016] The beneficial effects of this invention are: This invention takes high-efficiency evaporation as a breakthrough point and comprehensively applies the characteristics of silicon carbide. By setting up a boiling chamber, the evaporating liquid in the silicon carbide tube rises to the boiling chamber and reaches a boiling state after the pressure decreases, thus realizing integrated high-efficiency evaporation.

[0017] In this invention, a "liquid downwards, gas upwards" configuration is formed inside the silicon carbide tube. Under the upward force of the gas, the precipitate is suspended in the tube and then held by the liquid flow into the drain chamber. This avoids the formation of crystals or dirt inside the heating tube, facilitates the maintenance and cleaning of the equipment, ensures continuous and effective heat exchange, and extends the service life. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is an enlarged view of the heating chamber portion in this invention; Figure 3 This is a schematic diagram of the double-layer sealing structure in this invention.

[0019] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Example 1:

[0021] like Figures 1 to 3 As shown, this embodiment provides an evaporator, including a boiling chamber 1, a heating chamber 2 and a draining chamber 3 arranged sequentially from top to bottom. An upper tube sheet structure 4 is provided between the boiling chamber 1 and the heating chamber 2, and a lower tube sheet structure 5 is provided between the heating chamber 2 and the draining chamber 3.

[0022] Multiple silicon carbide tubes 20 are arranged inside the heating chamber 2, and each silicon carbide tube 20 extends in the vertical direction. The upper end of the silicon carbide tube 20 passes through the upper tube sheet structure and is connected to the boiling chamber 1. The lower end of the silicon carbide tube 20 passes through the lower tube sheet structure and is connected to the drain chamber 3.

[0023] The heating chamber 2 forms a heat exchange space outside the silicon carbide tube 20. The side of the heating chamber 2 is provided with a heat transfer medium inlet 21 and a heat transfer medium outlet 22 that communicate with the heat exchange space for introducing high-temperature steam. In this embodiment, the heat transfer medium inlet 21 is located at the upper part of one side of the heating chamber 2, and the heat transfer medium outlet 22 is located at the lower part of the other side of the heating chamber 2.

[0024] The boiling chamber 1 is located at the top of the heating chamber 2 and is made of a high-temperature resistant alloy material (resistant to high temperature and strong corrosion, etc.). Composite materials can also be used to reduce costs. The volume of the boiling chamber 1 is 2-3 times the total volume of the silicon carbide tubes 20 in the heating chamber 2.

[0025] The boiling chamber 1 has a liquid inlet 11 on one side and a circulating liquid inlet 13 on the other side. The top of the boiling chamber 1 has an exhaust port 12, and the space between the exhaust port 22 and the liquid inlet 21 is 1 / 3 of the volume of the boiling chamber.

[0026] The top of the boiling chamber 1 is also equipped with a level gauge port 14 and a pressure gauge / thermometer / sight glass port 15.

[0027] The drain chamber 3 is located at the bottom of the heating chamber 2, and a drain port 31 is provided at the bottom of the drain chamber 3 for draining liquid. The drain chamber 3 is made of alloy material and can withstand high temperature, high pressure corrosion, and strong acids and alkalis.

[0028] In this embodiment, the upper tube sheet structure 4 includes a first upper tube sheet 41, a reinforcing plate 42, a support ring 43, and a second upper tube sheet 44 arranged sequentially from top to bottom. The first upper tube sheet 41 is made of PTFE, and the second upper tube sheet 44 is made of carbon steel.

[0029] The outer periphery of the first upper tube sheet 41, the reinforcing plate 42, and the second upper tube sheet 44 is provided as flange rings. Bolts pass through the bottom flange of the boiling chamber 1, the first upper tube sheet 41, the reinforcing plate 42, the second upper tube sheet 43, and the top flange of the heating chamber 2 to clamp and fix the upper tube sheet structure 4. Furthermore, sealing rings are provided between the bottom flange of the boiling chamber 1, the first upper tube sheet 41, the reinforcing plate 42, the support ring 43, the second upper tube sheet 44, and the top flange of the heating chamber 2 to ensure the sealing of the component connections.

[0030] The first upper tube plate 41 is provided with first upper distribution holes 411 corresponding to the silicon carbide tubes 20, and the second upper tube plate 44 is provided with first lower distribution holes 441 corresponding to the silicon carbide tubes 20. The upper end of the silicon carbide tube 20 passes through the first lower distribution hole 441 and the first upper distribution hole 411, and a first lower sealing structure is provided between the silicon carbide tube 20 and the first lower distribution hole 441, and a first upper sealing structure is provided between the silicon carbide tube 20 and the first upper distribution hole 411, thereby forming a double-layer sealing structure.

[0031] In this embodiment, the silicon carbide tube 20 is fitted with a PTFE gasket, a perfluoroether O-ring, another PTFE gasket, another perfluoroether O-ring, and another perfluoroether O-ring sequentially from top to bottom at the first upper distribution hole 411 position, forming a first upper sealing structure. Furthermore, a first lower pressure ring is provided at the upper end of the uppermost gasket to limit the gasket's position.

[0032] In this embodiment, the silicon carbide tube 20 is fitted with a PTFE gasket, a perfluoroether O-ring, another PTFE gasket, another perfluoroether O-ring, and another perfluoroether O-ring sequentially from top to bottom at the first lower distribution hole 441, forming a first lower sealing structure. Furthermore, a first upper pressure ring is provided at the upper end of the uppermost gasket to limit its position.

[0033] To facilitate the arrangement of the sealing gasket, the first lower distribution hole 441 can also be in the form of a stepped hole.

[0034] The silicon carbide tube 20 is made of a different material than the first upper tube sheet 41 / second upper tube sheet 44, resulting in different deformation and allowance after heating. Therefore, a double-layer structure is required for sealing. The sealing effect of the double-layer sealing structure mainly relies on the perfluoroether O-ring, while the PTFE gasket provides support for the sealing combination. The perfluoroether O-ring can withstand temperatures up to 300 degrees Celsius, and overheated steam will not damage it.

[0035] The support ring 43 is equipped with a leakage port, which is connected to a leakage alarm device. If the seal between the silicon carbide tube 20 and the first upper tube sheet 41 is damaged, the leaked liquid will enter the space where the support ring 43 is located, and the leakage alarm device will issue an alarm signal to remind the staff to handle the situation.

[0036] In this embodiment, the lower tube sheet structure 5 and the upper tube sheet structure 4 are arranged symmetrically.

[0037] The working principle of this invention is as follows: The heat transfer medium inlet 21 is filled with hot steam, and the liquid (fluorine-containing liquid, which can be ammonium fluoride or ammonium bifluoride solution) in the boiling chamber 1 enters from the upper end of the silicon carbide tube 20. The operating temperature inside the silicon carbide tube 20 is 80-120℃, and the operating pressure is 0.15 MPa. The operating temperature of the heating chamber 2 is 100~200℃, and the operating pressure is 0.35 MPa.

[0038] When the liquid passes through the tube side of heater 2, it is rapidly vaporized by the hot steam. This process is a process of removing impurities (the feed concentration in the tube side is 30%, and the discharge concentration is 70%). The liquid that is not vaporized remains in the drain chamber 3 and is connected to the external slag discharge tank through the drain port 31 for further utilization and treatment.

[0039] The vaporized (fluorine-containing liquid) flows upward through the silicon carbide tube 20, colliding with the downward-flowing liquid. The amount of vaporization is greater than the surface area of ​​the liquid, and it enters the boiling chamber 1 to form a bubble state (since the volume of the boiling chamber 1 is 2-3 times the total volume of the silicon carbide tube 20 in the heating chamber 2, the pressure on the evaporating liquid decreases after entering the boiling chamber 1, thus achieving a boiling state). This process is also a preheating state for the liquid that has just entered the boiling chamber.

[0040] This invention takes high-efficiency evaporation as a breakthrough point and comprehensively applies the characteristics of silicon carbide (high heat transfer coefficient, resistance to acid and alkali corrosion, etc.) to achieve high-efficiency heat exchange and realize integrated evaporation.

[0041] In this invention, a "liquid downwards, gas upwards" configuration is formed inside the silicon carbide tube 20. Under the upward action of the gas, the precipitate is suspended in the tube and then held by the liquid flow into the drain chamber 3. This avoids the formation of crystals or dirt inside the heating tube, facilitates the maintenance and cleaning of the equipment in the later stages, ensures the continuous and effective heat exchange effect, and has a long service life. Example 2:

[0042] In this embodiment, the lower tube sheet structure 5 can be a common single-layer tube sheet structure.

[0043] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

[0044] If the terms "first" or "second" are used in this document to define components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing the invention and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. An evaporator, characterized in that: It includes a boiling chamber, a heating chamber and a draining chamber arranged from top to bottom. An upper tube sheet structure is provided between the boiling chamber and the heating chamber, and a lower tube sheet structure is provided between the heating chamber and the draining chamber. Multiple silicon carbide tubes are arranged in the heating chamber, each extending vertically; the upper end of the silicon carbide tube passes through the upper tube sheet structure and is connected to the boiling chamber; the lower end of the silicon carbide tube passes through the lower tube sheet structure and is connected to the drain chamber. The space outside the silicon carbide tube is formed in the heating chamber, and the side of the heating chamber is provided with a heat transfer medium inlet and a heat transfer medium outlet that are connected to the heat transfer space. The volume of the boiling chamber is greater than the total volume of the silicon carbide tubes in the heating chamber. The boiling chamber is equipped with a liquid inlet and an exhaust outlet.

2. The evaporator according to claim 1, characterized in that: The volume of the boiling chamber is 2-3 times the total volume of the silicon carbide tubes in the heating chamber.

3. The evaporator according to claim 1 or 2, characterized in that: The liquid inlet is located on the side of the boiling chamber, and the exhaust port is located on the top of the boiling chamber. The space between the liquid inlet and the exhaust port is more than 1 / 3 of the volume of the boiling chamber.

4. The evaporator according to claim 3, characterized in that: The upper tube sheet structure includes a first upper tube sheet, a reinforcing plate, and a second upper tube sheet arranged sequentially from top to bottom. The first upper tube sheet, the reinforcing plate, and the second upper tube sheet are clamped and fixed between the boiling chamber and the heating chamber, and the first upper tube sheet, the reinforcing plate, and the second upper tube sheet are respectively provided with sealing devices between each other. The first upper tube sheet is provided with first upper distribution holes corresponding to the silicon carbide tubes, and the second upper tube sheet is provided with first lower distribution holes corresponding to the silicon carbide tubes. The upper end of the silicon carbide tube passes through the first lower distribution hole and the first upper distribution hole, and a first lower sealing structure is provided between the silicon carbide tube and the first lower distribution hole, and a first upper sealing structure is provided between the silicon carbide tube and the first upper distribution hole, thereby forming a double-layer sealing structure.

5. The evaporator according to claim 4, characterized in that: The first upper tube sheet is made of PTFE, and the second upper tube sheet is made of carbon steel.

6. The evaporator according to claim 5, characterized in that: The silicon carbide tube is fitted with a PTFE gasket, a perfluoroether O-ring, a PTFE gasket, a perfluoroether O-ring, and a perfluoroether O-ring in sequence from top to bottom at the first upper distribution hole position, forming a first upper sealing structure; The silicon carbide tube is fitted with a PTFE gasket, a perfluoroether O-ring, a PTFE gasket, a perfluoroether O-ring, and a perfluoroether O-ring in sequence from top to bottom at the first lower distribution hole position, forming a first lower sealing structure.

7. The evaporator according to claim 4, characterized in that: A support ring is provided between the reinforcing plate and the second upper tube sheet, and a leakage port is provided on the support ring.

8. The evaporator according to any one of claims 4-7, characterized in that: The lower tube sheet structure and the upper tube sheet structure are arranged symmetrically.

9. The evaporator according to claim 1, characterized in that: The bottom of the drain chamber is provided with a drain port; the side of the boiling chamber is also provided with a circulating liquid port.

10. The evaporator according to claim 1, characterized in that: The heat transfer medium inlet is connected to the steam source.

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