A gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger

Abstract

A gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger. In the present invention, a shunt pipe (21) is arranged on the inner edge surface of the tube-side inlet (11), and then a plurality of shunt holes (22) are arranged at the lower part of the shunt pipe, so that the liquid water injected in front of the heat exchanger can be evenly distributed to the inlets of all heat exchange tube bundles, enabling each heat exchange tube bundle to be flushed with liquid water, effectively avoiding the risk of accidents such as the accumulation of crystalline ammonium salts at the inlet position of the heat exchange tube bundles, causing blockage or under-deposit corrosion leakage, and fully achieving the function of water injection. The present invention has the advantages of simple structure and good use effect, and is suitable for wide promotion and application.

Description

Technical Field

[0001] The present invention relates to a gas-liquid distribution device, and more particularly to a gas-liquid distribution device for preventing salt deposition corrosion in a heat exchanger. Background Art

[0002] It is known that during the production process of a hydrogenation unit, since the raw material to be processed contains elements such as sulfur, hydrogen, chlorine, and nitrogen, they will be converted into ammonium salts during the processing, namely ammonium chloride, ammonium sulfide, and ammonium bisulfide. After the generated ammonium salts enter the heat exchanger along with the gas-phase reaction products, i.e., high-temperature gases, due to heat exchange, the temperature of the high-temperature gases decreases, and the solubility of the ammonium salts in the gas-phase medium decreases, and then ammonium salts will precipitate to form crystals.

[0003] As Figure 1 、 2 shown, for a hydrogenation unit, since the reaction products, i.e., high-temperature gas 02, after entering the heat exchange tubes 16, i.e., the tube side of the heat exchanger, exchange heat with the cold medium in the shell side, and then the temperature decreases to form low-temperature gas 03. During this process, due to the decrease in the temperature of the reaction products, i.e., high-temperature gas 02, the solubility of the ammonium salts in the high-temperature gas 02 decreases, and then precipitated crystals are formed. In actual production, the precipitated crystalline ammonium salts 13 are mainly concentrated at the inlet position of the heat exchange tubes 16 of the heat exchanger. The crystalline ammonium salts 13 continuously deposit at the inlet of the heat exchange tubes 16, forming a fouling surface on the surface of the tube sheet 15 of the heat exchanger, which not only affects the heat exchange efficiency, increases the system energy consumption, but also seriously blocks the heat exchange tubes, causing process interruption and unit shutdown. At the same time, the ammonium salts themselves do not cause much corrosion, only causing blockage problems, but the ammonium salts are extremely hygroscopic and deliquescent. Under the condition of the presence of liquid water 01, a highly concentrated strong acidic corrosion environment is formed under the crystalline scale, causing extremely serious corrosion to the metal substrate, and even causing a malignant safety accident of perforation and leakage.

[0004] To avoid this phenomenon, most current hydrogenation units inject liquid water 01 before the heat exchanger, hoping to use the injected liquid water 01 to dissolve and wash the already formed crystalline ammonium salts 13 to avoid the accumulation of crystalline ammonium salts 13. However, the currently commonly used water injection method is to inject liquid water 01 into the pipeline in front of the inlet of the tube side of the heat exchanger, as Figure 1 shown.

[0005] However, since the hydrogenation unit operates under high-pressure reaction conditions, the heat exchangers are mostly floating head heat exchangers or U-tube heat exchangers. Heat exchangers of this structural type have a high working pressure and can be used in high-pressure environments such as hydrogenation units. However, since the tube side of such heat exchangers is provided with a partition plate 12 that divides the tube side into a tube side inlet 11 and a tube side outlet 14, this structure causes the gas-liquid mixture 04 to enter from the tube side inlet 11. Due to inertia, the liquid phase will directly impact the partition plate 12. The liquid water 01 will splash after hitting the partition plate 12 and then be distributed near the upper part of the partition plate 12. The gas phase will be distributed to each heat exchange tube along with the pipeline and head structure. That is to say, gas-liquid separation occurs. Most of the injected liquid water 01 only flows into the heat exchange tube bundle 16 located at the lower part, and the heat exchange tube bundle 16 in the upper part cannot be fully flushed, resulting in the accumulation of crystalline ammonium salts 13 at the inlets of the heat exchange tube bundles 16 in the upper part and surrounding areas, causing problems such as blockage and corrosion leakage, as Figure 2 shown, and the function of water injection cannot be fully achieved.

[0006] Therefore, there is an urgent need to provide a gas-liquid distribution device that can change the uneven gas-liquid distribution phenomenon after water injection in the existing heat exchanger, so as to evenly distribute the liquid water 01 injected before the heat exchanger to the inlets of all heat exchange tube bundles. Summary of the Invention

[0007] To overcome the deficiencies in the background technology, the present invention provides a gas-liquid distribution device for preventing salt formation and corrosion in heat exchangers. The shunt tube in the present invention can evenly distribute the liquid water injected before the heat exchanger to the inlets of all heat exchange tube bundles, enabling each heat exchange tube bundle to be flushed with liquid water, effectively avoiding the accumulation of crystalline ammonium salts at the inlets of the heat exchange tube bundles, preventing accidents such as blockage or corrosion leakage under scale, and fully achieving the function of water injection, etc.

[0008] To achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions:

[0009] A gas-liquid distribution device for preventing salt formation and corrosion in heat exchangers includes a shunt tube and shunt holes. The shunt tube is a tubular structure with openings at both ends. The upper part of the shunt tube is inserted into the inner edge surface of the tube side inlet of the heat exchanger. A plurality of shunt holes are spacedly arranged on the outer edge surface of the middle and lower parts of the shunt tube. Each shunt hole faces the inlet of the heat exchange tube bundle of the heat exchanger. The lower end opening of the shunt tube faces and is close to the partition plate of the heat exchanger to form the gas-liquid distribution device for preventing salt formation and corrosion in the heat exchanger.

[0010] In the gas-liquid distribution device for preventing salt formation and corrosion in the heat exchanger, the shunt hole is any one of a round hole, a conical hole, or a special-shaped hole.

[0011] In the gas-liquid distribution device for preventing salt formation and corrosion in the heat exchanger, when the shunt hole is set as a round hole, the diameter of the round hole is not greater than one-third of the inner diameter of the shunt tube.

[0012] The gas-liquid distribution device for preventing salt deposition corrosion of the heat exchanger, each shunt hole faces the inlet of the heat exchange tube bundle in the upper-middle area of the tube sheet.

[0013] The gas-liquid distribution device for preventing salt deposition corrosion of the heat exchanger, the outer edge surface of the upper part of the shunt pipe is in interference connection with the inner edge surface of the tube side inlet.

[0014] The gas-liquid distribution device for preventing salt deposition corrosion of the heat exchanger, the replacement structure of the shunt pipe is that the shunt pipe includes a pipe body and a connecting flange. A connecting flange is provided at the upper end of the pipe body, and the connecting flange is clamped at the tube side inlet. A plurality of shunt holes are arranged at intervals on the outer edge surface of the middle and lower parts of the shunt pipe.

[0015] Adopting the above technical solution, the present invention has the following advantages:

[0016] By arranging the shunt pipe on the inner edge surface of the tube side inlet and then arranging a plurality of shunt holes at the lower part of the shunt pipe, the present invention can evenly distribute the liquid water injected before the heat exchanger to the inlets of all the heat exchange tube bundles, so that each heat exchange tube bundle can be flushed with liquid water, effectively avoiding the risk of accidents such as the accumulation of crystalline ammonium salt at the inlet position of the heat exchange tube bundle, causing blockage or corrosion leakage under scale, and fully achieving the function of water injection. The present invention has the advantages of simple structure and good use effect, and is suitable for wide promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the overall schematic diagram of the front road water injection of the existing hydrogenation heat exchanger;

[0018] Figure 2 is Figure 1 the partial schematic view in the A direction of;

[0019] Figure 3 is the schematic diagram of the structure and its application of the present invention;

[0020] Figure 4 is Figure 3 the sectional structure schematic view of B-B of;

[0021] Figure 5 is the schematic diagram of the working state of the present invention;

[0022] Figure 6 is Figure 5 the sectional structure schematic view of C-C of;

[0023] Figure 7 is the schematic diagram of another structure and its application of the present invention;

[0024] In the figure: 01, liquid water; 02, high-temperature gas; 03, low-temperature gas; 04, gas-liquid mixture; 11, tube-side inlet; 12, partition plate; 13, crystallized ammonium salt; 14, tube-side outlet; 15, tube sheet; 16, heat exchange tube bundle; 21, shunt tube; 22, shunt hole. Detailed implementation mode

[0025] The present invention can be more detailedly explained through the following embodiments, and the present invention is not limited to the following embodiments;

[0026] First of all, it should be noted that the orientation or positional relationship indicated by "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. adopted by the present invention when describing the structure is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of description and simplification of description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention.

[0027] Combined with the attached Figures 3 to 7 A gas-liquid distribution device for preventing salt deposition and corrosion of a heat exchanger shown in the figure, including a shunt tube 21 and shunt holes 22. The shunt tube 21 is a tubular structure with openings at both ends. The upper part of the shunt tube 21 is inserted into the inner edge surface of the tube-side inlet 11 of the heat exchanger. The outer edge surface of the upper part of the shunt tube 21 is in interference connection with the inner edge surface of the tube-side inlet 11 or the upper part of the shunt tube 21 is directly welded to the inner edge surface of the tube-side inlet 11. A plurality of shunt holes 22 are arranged at intervals on the outer edge surface of the lower part of the shunt tube 21. The shunt holes 22 are any one of round holes, conical holes or special-shaped holes. Each shunt hole 22 faces the inlet of the heat exchange tube bundle of the heat exchanger, that is, each shunt hole 22 faces the inlet of the heat exchange tube bundle in the upper-middle area of the tube sheet 15. The lower end opening of the shunt tube 21 faces and is close to the partition plate 12 of the heat exchanger to form the gas-liquid distribution device for preventing salt deposition and corrosion of the heat exchanger.

[0028] During specific implementation, the hole in the middle of the shunt tube 21 can be a conical hole with a larger upper end and a smaller lower end, that is, the aperture of the upper end of the shunt tube 21 is larger than the aperture of the lower end of the shunt tube 21.

[0029] Combined with the attached Figure 5 and 6, when the present invention is in the working state, liquid water 01 is injected from the opening of the pipeline in front of the inlet 11 of the heat exchanger tube. After mixing with the high-temperature gas 02, a gas-liquid mixture 04 is formed. After the gas-liquid mixture 04 enters the shunt tube 21, due to the guiding effect of the cylindrical structure of the shunt tube 21 and the blockage of the gas phase by the partition plate 12 corresponding to the outlet of the shunt tube 21, the gas phase in the gas-liquid mixture 04 will be pressured, and a certain high pressure will be formed inside the shunt tube 21, and then it will be ejected from the shunt holes 22 on the shunt tube 21. At the same time of ejection, the liquid phase in the gas-liquid mixture 04 will be carried by the ejected gas phase to form the ejection of the gas-liquid mixture 04 together.

[0030] Preferably, the shunt holes 22 are set as round holes, the diameter of the round holes is not greater than one-third of the inner diameter of the shunt tube 21, and the diameter of the round holes is not less than 1 mm. The aperture set within this range will enable the gas-liquid mixture 04 to be ejected from the shunt holes 22 at a speed of 0-5 m / s.

[0031] Since the shunt holes 22 on the shunt tube 21 are respectively oriented towards different regions in the upper and middle parts of the heat exchange tube bundle inlet, the ejection of the gas-liquid mixture 04 will evenly cover the upper and middle parts of the entire heat exchange tube bundle inlet. At the same time, since the outlet of the shunt tube 21 is not completely connected to the partition plate 12, part of the gas-liquid mixture 04 still flows out from the outlet of the shunt tube 21, forms a sputtering of the gas-liquid mixture 04 after hitting the partition plate 12, and then enters the lower part of the heat exchange tube bundle inlet. The combination of the above two aspects enables the injected liquid water 01 to basically completely cover the heat exchange tube bundle inlet, that is, when the high-temperature gas 02 in the gas phase enters the heat exchange tube 16 for heat exchange, it can also carry the liquid water 01 in the liquid phase to wash the position of the heat exchange tube bundle inlet, thereby avoiding the problems of blockage, corrosion and leakage caused by crystalline ammonium salts.

[0032] Appendix Figure 7 For another embodiment of the present invention, in practical applications, since it is difficult to construct the shunt tube 21 inside the tube inlet 11, and the bonding strength of the two-layer tubular structure will decrease after welding during long-term use, resulting in fatigue failure and the risk of the shunt tube 21 falling off. Therefore, in the actual implementation method, the structure of the shunt tube 21 as shown in Appendix Figure 7 can be adopted, that is, the replacement structure of the shunt tube 21 is that the shunt tube 21 includes a tube body and a connecting flange. A connecting flange is provided at the upper end of the tube body to form an integral structure. The connecting flange is clamped at the tube inlet 11 to form a flange sandwich installation form. A plurality of shunt holes 22 are provided at intervals on the outer edge surface in the middle and lower parts of the shunt tube 21. During the implementation process, the connecting flange can be a sandwich flange cover. After the connecting flange and the tube body are integrally manufactured, they are integrally placed into the tube inlet 11. This technical solution is also within the protection scope of the present invention.

[0033] The present invention is suitable for applications where existing heat exchangers suffer from uneven gas-liquid distribution, resulting in salt deposition at the inlet of the heat exchange tubes, leading to corrosion and leakage. It is also applicable to other similar locations of fouling and corrosion in heat exchangers.

[0034] Parts not detailed in the present invention are prior art.

[0035] Examples selected herein for disclosing the object of the present invention are considered suitable at present. However, it should be understood that the present invention is intended to cover all variations and improvements of all examples falling within the scope of this concept and invention.

Claims

1. A gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger, characterized in that: It includes a flow dividing pipe (21) and flow dividing holes (22). The flow dividing pipe (21) is a tubular structure with openings at both ends. The upper part of the flow dividing pipe (21) is inserted into the inner edge surface of the inlet of the heat exchanger tube pass (11). A plurality of flow dividing holes (22) are spaced on the outer edge surface of the middle and lower parts of the flow dividing pipe (21). Each of the flow dividing holes (22) faces the inlet of the heat exchange tube bundle of the heat exchanger. The lower end opening of the flow dividing pipe (21) faces and is close to the partition plate (12) of the heat exchanger to form the gas-liquid distribution device for preventing the heat exchanger from salt deposition corrosion.

2. The gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger according to claim 1, characterized in that: The flow dividing hole (22) is any one of a round hole, a tapered hole or a special-shaped hole.

3. The gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger according to claim 1, characterized in that: When the flow dividing hole (22) is set as a round hole, the diameter of the round hole is not greater than one-third of the inner diameter of the flow dividing pipe (21).

4. The gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger according to claim 1, characterized in that: Each of the flow dividing holes (22) faces the inlet of the heat exchange tube bundle in the upper-middle area of the tube sheet (15).

5. The gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger according to claim 1, characterized in that: The outer edge surface of the upper part of the flow dividing pipe (21) is in interference connection with the inner edge surface of the tube pass inlet (11).

6. The gas-liquid distribution device for preventing salt deposition corrosion of a heat exchanger according to claim 1, characterized in that: The replacement structure of the flow dividing pipe (21) is that the flow dividing pipe (21) includes a pipe body and a connecting flange. A connecting flange is provided at the upper end of the pipe body. The connecting flange is clamped at the tube pass inlet (11). A plurality of flow dividing holes (22) are spaced on the outer edge surface of the middle and lower parts of the flow dividing pipe (21).

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