Preparation method of large-diameter steel lining four fluorine distillation kettle body

Abstract

A kind of preparation method of large-diameter steel lining four fluorine distillation kettle body, kettle body shell is made, arc reinforcing rib and glue hole are arranged in kettle body shell, four fluorine lining is opened by using the pressure of steam, since arc reinforcing rib supports the position where four fluorine lining and kettle body shell inner wall adhere, larger gap of four fluorine lining is supported by using arc reinforcing rib, the air between adhesive brushed on kettle body shell inner wall and four fluorine lining and kettle body shell is gathered to larger gap, and is discharged from glue hole below arc reinforcing rib, and adhesive is wrapped around arc reinforcing rib, after presetting time of glue removal, airless glue layer is formed between kettle body shell inner wall, four fluorine lining and arc reinforcing rib, four fluorine lining is fixed on kettle body shell inner wall and arc reinforcing rib by using glue layer, finally, four fluorine lining is firmly fixed on the inner wall of kettle body shell, and the service life of large-diameter steel lining four fluorine distillation kettle body is prolonged.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment technology, and in particular to a method for preparing a large-diameter steel-lined PTFE distillation vessel. Technical Background

[0002] Chemical corrosion-resistant equipment is widely used in chemical production and chemical raw material storage. Currently, the production of corrosion-resistant equipment mainly involves covering the inside of the equipment body with anti-corrosion plastic lining to form corrosion protection. The main body of such equipment is mostly made of materials such as carbon steel. In recent years, distillation kettles with PTFE linings have become increasingly popular among chemical manufacturers due to their excellent acid and alkali resistance.

[0003] However, as the demand for chemical production leads to increasingly larger diameter distillation vessels, the expansion coefficient of PTFE differs significantly from that of carbon steel. PTFE's expansion coefficient is approximately 10 times that of carbon steel. This results in the PTFE lining inside the large-diameter vessel shell not adhering firmly, easily causing the PTFE lining to detach from the vessel shell and leading to leakage. The larger the diameter of the distillation vessel, the greater the probability of the PTFE lining detaching from the vessel shell, seriously affecting safe production. Therefore, application number 202111655948.7, entitled "Manufacturing Method of Polytetrafluoroethylene Anti-corrosion Equipment and Polytetrafluoroethylene Anti-corrosion Equipment", discloses a method of welding ribs inside a pre-formed steel anti-corrosion equipment, roughening the inner wall of the anti-corrosion equipment, applying adhesive to the inner wall of the anti-corrosion equipment, roughening the outer wall of the polytetrafluoroethylene liner, heating and softening the polytetrafluoroethylene liner with steam, and simultaneously using the pressure of steam to expand the polytetrafluoroethylene liner, so that the polytetrafluoroethylene liner adheres to the inner wall of the anti-corrosion equipment. While being heated by steam, the adhesive melts and fills the scratches on the roughened surface of the polytetrafluoroethylene outer wall, so that the polytetrafluoroethylene liner is firmly bonded to the inner wall of the anti-corrosion equipment, which greatly improves the bonding strength between the polytetrafluoroethylene liner and the anti-corrosion equipment and extends the service life of the anti-corrosion equipment. However, in this existing technology, the discharge holes are distributed between two ribs, and a large distance is maintained between the discharge holes and the ribs. Although some air between the PTFE liner and the inner wall of the corrosion-resistant equipment can flow along the guide channel to the discharge holes and be discharged during steam pressurization, some air needs to pass through the ribs to reach the discharge holes. Since the pressure is the same at every point during steam pressurization, some air remains between the PTFE liner and the inner wall of the corrosion-resistant equipment near both ends of the cylinder. More air remains around the side of the rib closer to the cylinder. During subsequent use of the corrosion-resistant equipment, the thermal expansion of this residual air will cause the PTFE liner and the inner wall of the corrosion-resistant equipment to gradually separate. Bulges will occur in areas with more residual air than around the ribs, seriously affecting safe production. Summary of the Invention

[0004] In view of this, the present invention provides a method for preparing a large-diameter steel-lined PTFE distillation vessel to solve the problem in the prior art that the PTFE liner and the vessel shell are prone to detachment due to the increased diameter of the distillation vessel.

[0005] A method for preparing a large-diameter steel-lined PTFE distillation vessel includes the following steps: S1. Making the outer shell of the vessel: The outer shell of the vessel is made by rolling steel plate into a cylindrical vessel shell with openings at the top and bottom. The two free ends of the cylindrical vessel shell are welded to obtain a cylinder with openings at the top and bottom. Annular flanges are welded to both ends of the cylinder to obtain the outer shell of the vessel. S2. Set arc-shaped reinforcing ribs and glue drain holes on the outer shell of the vessel: Fix the arc-shaped reinforcing ribs to the inner wall of the vessel shell by spot welding, and there is a gap between the arc-shaped reinforcing ribs and the inner wall of the vessel shell; open glue drain holes on the outer shell of the vessel, and the glue drain holes are directly opposite the arc-shaped reinforcing ribs. S3. Grinding and rust removal of the outer shell of the vessel body with arc-shaped reinforcing ribs and glue drain holes: Grinding and rust removal of the outer shell of the vessel body with arc-shaped reinforcing ribs and glue drain holes through sandblasting. S4. Fabrication of PTFE lining: Select polytetrafluoroethylene (PTFE) sheets and fabricate a PTFE lining that matches the shape and size of the vessel shell. S5. The prepared PTFE liner is subjected to sodium treatment. After the sodium treatment is completed, the PTFE liner is cleaned and dried. S6. Assembly of PTFE liner and vessel shell: Apply adhesive evenly to the inner wall of the vessel shell, ensuring that the adhesive is applied evenly and to a consistent thickness; place the sodium-treated PTFE liner inside the vessel shell and use supports to hold the PTFE liner open, so that the PTFE liner fits snugly against the inner wall of the vessel shell; perform flanging treatment on the fitted PTFE liner, and after the flanging treatment is completed, remove all supports; S7. Use a sealing device to seal both ends of the vessel shell with the PTFE liner. S8. Bonding and fixing of PTFE liner to vessel shell: Steam at 2.5-3.5 MPa is introduced into the vessel shell assembled with PTFE liner through the steam inlet pipe of the sealing device, and the temperature is maintained at 110-130℃ for 1-3 hours. The PTFE liner is uniformly squeezed towards the inner wall of the vessel shell by the steam pressure. During the process of the PTFE liner moving towards the inner wall of the vessel shell, the adhesive applied to the inner wall of the vessel shell is squeezed. The larger gap of the PTFE liner is supported by the arc-shaped reinforcing ribs, so that the adhesive applied to the inner wall of the vessel shell and the air between the PTFE liner and the vessel shell are gathered into the larger gap and discharged from the glue discharge hole below the arc-shaped reinforcing ribs. The adhesive wraps around the arc-shaped reinforcing ribs. After the glue discharge is carried out for a preset time, an air-free adhesive layer is formed between the inner wall of the vessel shell, the PTFE liner and the arc-shaped reinforcing ribs. The adhesive layer is used to fix the PTFE liner to the inner wall of the vessel shell and the arc-shaped reinforcing ribs. After the S9 PTFE liner is bonded and fixed to the outer shell of the vessel, the glue drain hole is sealed from the outside of the vessel shell to finally obtain a large-diameter steel-lined PTFE distillation vessel.

[0006] Preferably, the large-diameter steel-lined PTFE distillation vessel includes a steel-lined PTFE distillation vessel body, comprising a vessel shell and a PTFE liner. An arc-shaped reinforcing rib is provided on the inner wall of the vessel shell. Multiple adhesive drainage holes are provided on the vessel shell, directly opposite the arc-shaped reinforcing ribs. An inwardly protruding covering layer is provided on the PTFE liner, the height of which is adapted to the arc-shaped reinforcing ribs. The covering layer surrounds and covers the arc-shaped reinforcing ribs. A gel layer exists between the vessel shell and the PTFE liner. One side of the gel layer is bonded to the inside of the vessel shell and extends into the adhesive drainage hole. The other side of the gel layer is bonded to the outer wall of the PTFE liner. The arc-shaped reinforcing ribs are fixedly connected to the inner wall of the vessel shell by equally spaced weld joints. A gap exists between the arc-shaped reinforcing ribs and the inner wall of the vessel shell. The gel layer passes through the gap between the arc-shaped reinforcing ribs and the inner wall of the vessel shell and covers the arc-shaped reinforcing ribs, thereby using the gel layer and the arc-shaped reinforcing ribs to stably fix the vessel shell and the PTFE liner.

[0007] Preferably, a cylindrical plug fills one end of the glue discharge hole, and a plug is provided at the other end of the glue discharge hole. The cylindrical plug is close to the inner wall of the vessel shell, and the plug is close to the outer wall of the vessel shell. The plug and the glue discharge hole are welded and sealed together.

[0008] Preferably, the outer wall of the coating layer forms a groove, the cross-section of the groove matches the cross-section of the arc-shaped reinforcing rib, and the thickness of the coating layer is the same as the thickness of the PTFE liner near both ends of the vessel shell.

[0009] Preferably, the inner wall of the vessel shell is provided with at least one arc-shaped reinforcing rib, and the number of covering layers is consistent with the number of arc-shaped reinforcing ribs.

[0010] Preferably, a first flange and a second flange are respectively provided at both ends of the vessel shell. The first flange is provided with a plurality of first fixing holes, and the second flange is provided with a plurality of second fixing holes. The two ends of the PTFE liner are provided with a first flange and a second flange. The first flange covers the upper side of the first flange, and the outer edge of the first flange is close to the first fixing hole. The second flange covers the lower side of the second flange, and the outer edge of the second flange is close to the second fixing hole. A plurality of first reinforcing ribs are provided between the outer wall of the vessel shell and the first flange. The plurality of first reinforcing ribs are arranged around the outer wall of the vessel shell. A second reinforcing rib is provided between the outer wall of the vessel shell and the second flange. The second reinforcing rib is arranged around the outer wall of the vessel shell.

[0011] Preferably, the sealing device described in step S7 includes a first sealing head, a second sealing head, and a connecting rod. The middle position of the first sealing head is fixedly connected to the first end of the connecting rod, and the middle position of the second sealing head is detachably connected to the second end of the connecting rod. The edge of the first sealing head is provided with multiple first through holes, and the edge of the second sealing head is provided with multiple second through holes. A steam inlet pipe is provided on either the first or second sealing head.

[0012] Preferably, a pressure gauge is provided on the first or second sealing head, and a third through hole is provided at the middle position of the second sealing head. The first end of the connecting rod is fixedly connected to the first sealing head. The connecting rod is provided with an external thread of a predetermined length, and the external thread of the predetermined length is close to the second end of the connecting rod. The second end of the connecting rod passes through the third through hole of the second sealing head, and the external thread of the predetermined length is close to the third through hole of the second sealing head. The external thread of the predetermined length is located between the second sealing head and the second end of the connecting rod. The second end, which passes out of the third through hole of the second sealing head, passes through the sealing sleeve connecting rod in sequence to install a sealing sleeve and a fastening nut. The outer diameter of the sealing sleeve is adapted to the diameter of the third through hole, and the inner diameter of the sealing sleeve is adapted to the diameter of the connecting rod. The fastening nut pushes the sealing sleeve closer to the third through hole of the second sealing head by cooperating with the external thread of the connecting rod, so that the sealing sleeve is inserted into the annular gap between the third through hole of the second sealing head and the connecting rod. The outer side of the sealing sleeve is in sealing contact with the third through hole of the second sealing head, and the inner side of the sealing sleeve is in sealing contact with the connecting rod.

[0013] Preferably, a fourth through hole is provided at the middle position of the first sealing head, and one end of the connecting rod passes through the fourth through hole and is sealed and welded to the first sealing head. Multiple reinforcing ribs are provided between the first sealing head and the connecting rod, and the reinforcing ribs are distributed on either side of the first sealing head. The multiple reinforcing ribs are distributed around the connecting rod.

[0014] Preferably, the sealing sleeve is a conical sealing sleeve, that is, the thickness of the outer wall of the sealing sleeve gradually decreases at one end and gradually increases at the other end.

[0015] In the aforementioned method for preparing a large-diameter steel-lined PTFE distillation vessel, arc-shaped reinforcing ribs are welded to the inner wall of the vessel shell. Multiple adhesive drainage holes are opened on the outer wall of the vessel shell at corresponding locations of the arc-shaped reinforcing ribs. Steam pressure is used to expand the PTFE liner. Because the arc-shaped reinforcing ribs support the PTFE liner, the contact point between the PTFE liner and the arc-shaped reinforcing ribs is slightly higher than the contact point between the PTFE liner and the inner wall of the vessel shell. This results in a slightly larger distance between the PTFE liner near the arc-shaped reinforcing ribs and the inner wall of the vessel shell compared to the distance further away from the arc-shaped reinforcing ribs. During steam pressurization, the pressure on the molten colloid between the PTFE liner far from the arc-shaped reinforcing ribs and the inner wall of the vessel shell is greater than that near the arc-shaped reinforcing ribs. The pressure exerted on the molten colloid between the PTFE liner at the rib and the inner wall of the vessel shell facilitates the flow of the molten colloid between the PTFE liner away from the arc-shaped reinforcing rib and the inner wall of the vessel shell towards the arc-shaped reinforcing rib. Furthermore, the gap between the arc-shaped reinforcing rib and the inner wall of the vessel shell allows residual air between the inner wall of the vessel shell and the PTFE liner to flow out through the discharge hole directly opposite the arc-shaped reinforcing rib along with the molten colloid. After a preset discharge period, an air-free colloid layer is formed between the inner wall of the vessel shell and the PTFE liner, reducing the difference in deformation caused by thermal expansion and contraction between the PTFE liner and the vessel shell. Ultimately, this firmly fixes the PTFE liner to the inner wall of the vessel shell, extending the service life of the large-diameter steel-lined PTFE distillation vessel. Attached Figure Description

[0016] Figure 1 This is a front view schematic diagram of the vessel shell manufactured using the present invention.

[0017] Figure 2 yes Figure 1 Cross-sectional view of section AA.

[0018] Figure 3 This is a cross-sectional view of the large-diameter steel-lined PTFE distillation vessel prepared using the present invention.

[0019] Figure 4 yes Figure 3 Enlarged view of point B in the middle.

[0020] Figure 5 This is a structural diagram of the sealing device used in the manufacture of a large-diameter steel-lined PTFE distillation vessel using the present invention.

[0021] Figure 6 This is a 3D view of the first sealing head.

[0022] Figure 7 This is a 3D view of the second sealing head.

[0023] Figure 8 This is a cross-sectional view of the sealing device.

[0024] Figure 9yes Figure 8 A magnified view of point C in the middle.

[0025] Figure 10 This diagram shows the state after the two ends of a large-diameter steel-lined PTFE distillation vessel are sealed with a sealing device and steam is introduced to tighten the lining.

[0026] In the figure: outer shell of the vessel 10, arc-shaped reinforcing rib 11, glue drain hole 12, first flange 13, first fixing hole 131, second flange 14, second fixing hole 141, first reinforcing rib plate 15, second reinforcing rib plate 16, PTFE liner 20, coating layer 21, groove 211, first flange 22, second flange 23, adhesive layer 30, cylindrical plug 31, plug 40, sealing device 50, first sealing plug 51, first through hole 511, fourth through hole 512, second sealing plug 52, second through hole 521, third through hole 522, connecting rod 53, sealing sleeve 531, fastening nut 532, steam inlet pipe 54, pressure gauge 55, limit block 56. Detailed Implementation

[0027] The technical solutions and effects of specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Please see Figures 1 to 10 The present invention will be further described in detail below.

[0029] This invention provides a method for preparing a large-diameter steel-lined PTFE distillation vessel, which specifically includes the following steps: A method for preparing a large-diameter steel-lined PTFE distillation vessel includes the following steps: S1. Making the outer shell 10 of the vessel: The outer shell 10 of the vessel is made by rolling steel plate into a cylindrical vessel shell 10 with openings at the top and bottom. The two free ends of the cylindrical vessel shell 10 are welded to obtain a cylindrical body with openings at the top and bottom. Annular flanges are welded to both ends of the cylindrical body to obtain the outer shell 10 of the vessel. S2. An arc-shaped reinforcing rib 11 and a glue drain hole 12 are provided on the outer shell 10 of the vessel body: The arc-shaped reinforcing rib 11 is fixed to the inner wall of the outer shell 10 of the vessel body by spot welding, and there is a gap between the arc-shaped reinforcing rib 11 and the inner wall of the outer shell 10 of the vessel body; a glue drain hole 12 is opened on the outer shell 10 of the vessel body, and the glue drain hole 12 is directly opposite the arc-shaped reinforcing rib 11. S3. Grinding and rust removal of the outer shell 10 of the vessel body with arc-shaped reinforcing ribs 11 and glue drain holes 12: Grinding and rust removal of the outer shell 10 of the vessel body with arc-shaped reinforcing ribs 11 and glue drain holes 12 by sandblasting. S4. Fabrication of PTFE liner 20: Select polytetrafluoroethylene sheet and fabricate PTFE liner 20 that matches the shape and size of the outer shell 10 of the vessel body. S5. The prepared PTFE liner 20 is subjected to sodium treatment. After the sodium treatment is completed, the PTFE liner 20 is cleaned and dried. S6. Assembly of PTFE liner 20 and vessel shell 10: Apply adhesive evenly to the inner wall of vessel shell 10, ensuring that the adhesive is applied evenly and to a uniform thickness; place the sodium-treated PTFE liner 20 inside the vessel shell 10 and use a bracket to open the PTFE liner 20 so that it fits against the inner wall of the vessel shell 10; perform flanging treatment on the fitted PTFE liner 20; after the flanging treatment is completed, remove all brackets. S7. Use sealing device 50 to seal both ends of the vessel shell 10 with PTFE liner 20 assembled. S8. Bonding and fixing of the PTFE liner 20 to the vessel shell 10: Steam at 2.5-3.5 MPa is introduced into the vessel shell 10, which is fitted with the PTFE liner 20, through the steam inlet pipe 54 of the sealing device 50. The temperature is maintained at 110-130℃ for 1-3 hours. The steam pressure is used to evenly compress the PTFE liner 20 towards the inner wall of the vessel shell 10. During this process, the PTFE liner 20 compresses the adhesive applied to the inner wall of the vessel shell 10. The bonding is achieved using the 11 arc-shaped reinforcing ribs. The larger gap of the PTFE liner 20 allows the adhesive applied to the inner wall of the vessel shell 10 and the air between the PTFE liner 20 and the vessel shell 10 to gather into the larger gap and be discharged from the adhesive discharge hole 12 below the arc-shaped reinforcing rib 11. The adhesive then wraps around the arc-shaped reinforcing rib 11. After a preset time of adhesive discharge, an air-free adhesive layer 30 is formed between the inner wall of the vessel shell 10, the PTFE liner 20, and the arc-shaped reinforcing rib 11. The adhesive layer 30 is used to fix the PTFE liner 20 to the inner wall of the vessel shell 10 and the arc-shaped reinforcing rib 11. After S9 and the PTFE liner 20 are bonded and fixed to the outer shell 10, the glue drain hole 12 is sealed from the outside of the outer shell 10 to finally obtain a large-diameter steel-lined PTFE distillation vessel.

[0030] Furthermore, the large-diameter steel-lined PTFE distillation vessel includes an outer shell 10 and a PTFE liner 20. The inner wall of the outer shell 10 is provided with arc-shaped reinforcing ribs 11, and the outer shell 10 has multiple adhesive drainage holes 12, which are directly opposite the arc-shaped reinforcing ribs 11. The PTFE liner 20 has an inwardly protruding covering layer 21, the height of which is adapted to the height of the arc-shaped reinforcing ribs 11. The covering layer 21 covers the arc-shaped reinforcing ribs 11. A gel layer 30 is located between the outer shell 10 and the PTFE liner 20. One side of the gel layer 30 is bonded to the interior of the outer shell 10, and the gel layer 30 extends into… A cylindrical plug 31 is formed in the glue discharge hole 12. The other side of the adhesive layer 30 is bonded to the outer wall of the PTFE liner 20. The arc-shaped reinforcing rib 11 is fixedly connected to the inner wall of the vessel shell 10 by equally spaced weld joints. The interval between the spot welds between the arc-shaped reinforcing rib 11 and the vessel shell 10 is 3cm to 5cm. There is a gap between the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10. The adhesive layer 30 passes through the gap between the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10 and covers the arc-shaped reinforcing rib 11, so as to use the adhesive layer 30 and the arc-shaped reinforcing rib 11 to stably fix the vessel shell 10 and the PTFE liner 20. Because the arc-shaped reinforcing rib 11 supports the PTFE liner 20, the distance between the PTFE liner 20 near the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10 is slightly larger than the distance between the PTFE liner 20 away from the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10. During steam pressurization, the molten colloid between the PTFE liner 20 away from the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10 experiences greater pressure. Because the PTFE liner 20 near the arc-shaped reinforcing rib 11 is supported by the arc-shaped reinforcing rib 11, the molten colloid between the PTFE liner 20 near the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10 experiences less pressure. Simultaneously, because the discharge hole is directly opposite the arc-shaped reinforcing rib 11... On the outer wall of the vessel shell 10 at point 1, the molten colloid is allowed to flow from a location away from the arc-shaped reinforcing rib 11 to the arc-shaped reinforcing rib 11 and then be discharged through the discharge hole 12. After a discharge process of about 3 hours, the colloid gradually cools and forms an air-free colloid layer 30 between the inner wall of the outer shell 10, the PTFE liner 20, and the arc-shaped reinforcing rib 11. The colloid layer 30 is used to fix the PTFE liner 20 to the inner wall of the outer shell 11 and the arc-shaped reinforcing rib 11. The cylindrical plug 31 and the plug 40 together seal the discharge hole 12, so that the colloid layer 30 of the steel-lined PTFE distillation vessel will not bulge due to excessive residual air and thermal expansion during actual use, thus extending the service life of the steel-lined PTFE distillation vessel.

[0031] Furthermore, to enhance the structural strength of the outer wall of the vessel shell 10, a cylindrical plug 31 fills one section of the glue discharge hole 12, and a plug 40 is installed at the other section of the glue discharge hole 12. The cylindrical plug 31 is located near the inner wall of the vessel shell 10, and the plug 40 is located near the outer wall of the vessel shell 10. The plug 40 and the glue discharge hole 12 are welded together in a sealed connection. The plug 40 is made of the same material as the vessel shell 10; both the vessel shell 10 and the plug 40 are made of steel or the same metal alloy.

[0032] Furthermore, a groove 211 is formed on the outer wall of the coating layer 21. The cross-section of the groove 211 matches the cross-section of the arc-shaped reinforcing rib 11, and the thickness of the coating layer 21 is the same as the thickness of the PTFE liner 20 near both ends of the vessel shell 10. Through the interlocking connection between the arc-shaped reinforcing rib 11 and the groove 211, and the filling of the adhesive layer 30 between the arc-shaped reinforcing rib 11 and the groove 211, the bonding strength between the arc-shaped reinforcing rib 11 and the groove 211 is further increased. When the vessel shell 10 and the PTFE liner 20 are heated, the phenomenon of separation due to the different thermal expansion of the two materials can also be overcome.

[0033] Furthermore, at least one arc-shaped reinforcing rib 11 is provided on the inner wall of the vessel shell 10, and the number of covering layers 21 is consistent with the number of arc-shaped reinforcing ribs 11. Multiple arc-shaped reinforcing ribs 11 not only enhance the structural strength of the vessel shell 10, but also allow more covering layers 21 and arc-shaped reinforcing ribs 11 to combine with the PTFE liner 20, thereby improving the adhesion between the PTFE liner 20 and the vessel shell 10.

[0034] Furthermore, a first flange 13 and a second flange 14 are respectively provided at both ends of the vessel shell 10. The first flange 13 has multiple first fixing holes 131, and the second flange 14 has multiple second fixing holes 141. The PTFE liner 20 has a first flange 22 and a second flange 23 at both ends. The first flange 22 covers the upper side of the first flange 13, with its outer edge close to the first fixing hole 131. The second flange 23 covers the lower side of the second flange 14, with its outer edge close to the second fixing hole 141. A plurality of first reinforcing ribs 15 are provided between the outer wall of the vessel shell 10 and the first flange 13. The plurality of first reinforcing ribs 15 are arranged around the outer wall of the vessel shell 10 to increase the structural strength of the first flange 13 and the vessel shell 10. A second reinforcing rib 16 is provided between the outer wall of the vessel shell 10 and the second flange 14. The second reinforcing rib 16 is arranged around the outer wall of the vessel shell 10 to increase the structural strength of the second flange 14 and the vessel shell 10.

[0035] Furthermore, the sealing device 50 described in step S7 includes a first sealing head 51, a second sealing head 52, and a connecting rod 53. The middle position of the first sealing head 51 is fixedly connected to the first end of the connecting rod 53, and the middle position of the second sealing head 52 is detachably connected to the second end of the connecting rod 53. The edge of the first sealing head 51 is provided with a plurality of first through holes 511, and the edge of the second sealing head 52 is provided with a plurality of second through holes 521. A steam inlet pipe 54 is provided on the first sealing head 51 or the second sealing head 52. The first sealing head 51 is installed in an opening on one end face of the vessel shell 10 that needs to be sealed, and the second sealing head 52 is installed in an opening on the other end face of the vessel shell 10 that needs to be sealed. The two ends of the connecting rod 53 are respectively connected to the first sealing head 51 and the second sealing head 52. A bolt is installed in the first through hole 11 of the first sealing head 51 and tightened to seal one end edge of the vessel shell 10. A bolt is installed in the second through hole 21 of the second sealing head 52 and tightened to seal the other end edge of the vessel shell 10. The sealing device seals the vessel shell with the PTFE liner already installed. After the two ends of 10 are sealed, a sealed cavity is formed. Even if pressurized steam is introduced into the sealed cavity through the steam inlet pipe 54, the two ends of the connecting rod 53 pull the middle position of the first sealing head 51 and the second sealing head 52 respectively, preventing the middle of the first sealing head 51 and the second sealing head 52 from bulging outward. This ensures that the first sealing head 51 and the second sealing head 52 are tightly and flatly attached to the sealing positions of the two ends of the vessel shell 10, and are in a sealed state. Then, after adding steam and pressurizing, the PTFE liner 20 is tightly lined to the inner wall of the vessel shell 10.

[0036] Furthermore, a pressure gauge 55 is installed on the first sealing head 51 or the second sealing head 52. The pressure gauge 55 is used to detect the real-time pressure value after steam is introduced into the sealed cavity. A third through hole 522 is provided at the middle position of the second sealing head 52. The first end of the connecting rod 53 is fixedly connected to the first sealing head 51. The connecting rod 53 is provided with an external thread of a predetermined length, and the external thread of the predetermined length is close to the second end of the connecting rod 53. The second end of the connecting rod 53 passes through the third through hole 522 of the second sealing head 52, and the external thread of the predetermined length is close to the third through hole 522 of the second sealing head 52. The external thread of the predetermined length is located between the second sealing head 52 and the second end of the connecting rod 53. The second end of the connecting rod 53 passes through the third through hole 522 of the second sealing head 52. A sealing sleeve 531 and a fastening nut 532 are installed sequentially on the connecting rod 53. The outer diameter of the sealing sleeve 531 matches the diameter of the third through hole 522, and the inner diameter of the sealing sleeve 531 matches the diameter of the connecting rod 53. The fastening nut 532 pushes the sealing sleeve 531 closer to the third through hole 522 of the second plug head 52 by engaging with the external thread of the connecting rod 53, so that the sealing sleeve 531 is inserted into the annular gap between the third through hole 522 of the second plug head 52 and the connecting rod 53. The outer side of the sealing sleeve 531 is in sealing contact with the third through hole 522 of the second plug head 52, and the inner side of the sealing sleeve 531 is in sealing contact with the connecting rod 53, preventing the pressurized steam from leaking from the gap formed by the connecting rod 53 and the third through hole 522.

[0037] Furthermore, a fourth through hole 512 is provided at the middle position of the first sealing head 51. One end of the connecting rod 53 passes through the fourth through hole 512 and is sealed and welded to the first sealing head 51. Multiple limiting blocks 56 are provided between the first sealing head 51 and the connecting rod 53. The limiting blocks 56 are distributed on either side of the first sealing head 51. The multiple limiting blocks 56 are distributed around the connecting rod 53. Each limiting block 56 is welded and fixed to the first sealing head 51 after being tightly attached.

[0038] Furthermore, the sealing sleeve 531 is a conical sealing sleeve 531, meaning that the thickness of the outer wall of the sealing sleeve 531 gradually decreases at one end and gradually increases at the other end. The conical shape of the sealing sleeve 531 facilitates insertion into the third through hole 522, and the outer wall of the sealing sleeve 531 can fit well with the inner wall of the third through hole 522, thereby increasing the sealing effect.

[0039] In the above-described method for preparing a large-diameter steel-lined PTFE distillation vessel, arc-shaped reinforcing ribs 11 are welded to the inner wall of the vessel shell 10. Multiple adhesive discharge holes 12 are opened on the outer wall of the vessel shell 10, corresponding to the arc-shaped reinforcing ribs 11. Steam pressure is used to expand the PTFE liner 20. Because the arc-shaped reinforcing ribs 11 support the PTFE liner 20, the contact point between the PTFE liner 20 and the arc-shaped reinforcing ribs 11 is slightly higher than the contact point between the PTFE liner 20 and the inner wall of the vessel shell 10. This results in a slightly larger distance between the PTFE liner 20 near the arc-shaped reinforcing ribs 11 and the inner wall of the vessel shell 10 compared to the distance further away from the arc-shaped reinforcing ribs 11. During steam pressurization, the pressure on the molten colloid between the PTFE liner 20 and the inner wall of the vessel shell 10 further away from the arc-shaped reinforcing ribs 11 is greater than the pressure on the molten colloid near the arc-shaped reinforcing ribs 11. The pressure exerted on the molten colloid between the PTFE liner 20 at the reinforcing rib 11 and the inner wall of the vessel shell 10 facilitates the flow of the molten colloid between the PTFE liner 20 and the inner wall of the vessel shell 10 away from the arc-shaped reinforcing rib 11 toward the arc-shaped reinforcing rib 11. Furthermore, the gap between the arc-shaped reinforcing rib 11 and the inner wall of the vessel shell 10 allows air remaining between the inner wall of the vessel shell 10 and the PTFE liner 20 to flow out through the discharge hole 12 directly opposite the arc-shaped reinforcing rib 11 along with the flow of the molten colloid. After a preset discharge period, an air-free colloid layer 30 is formed between the inner wall of the vessel shell 10 and the PTFE liner 20, reducing the difference in deformation between the PTFE liner 20 and the vessel shell 10 due to thermal expansion and contraction. Ultimately, this firmly fixes the PTFE liner 20 to the inner wall of the vessel shell 10, extending the service life of the large-diameter steel-lined PTFE distillation vessel.

Claims

1. A method for preparing a large-diameter steel-lined PTFE distillation vessel, characterized in that, Includes the following steps: S1. Making the outer shell of the vessel: The outer shell of the vessel is made by rolling steel plate into a cylindrical vessel shell with openings at the top and bottom. The two free ends of the cylindrical vessel shell are welded to obtain a cylinder with openings at the top and bottom. Annular flanges are welded to both ends of the cylinder to obtain the outer shell of the vessel. S2. Set arc-shaped reinforcing ribs and glue drain holes on the outer shell of the vessel: Fix the arc-shaped reinforcing ribs to the inner wall of the vessel shell by spot welding, and there is a gap between the arc-shaped reinforcing ribs and the inner wall of the vessel shell; open glue drain holes on the outer shell of the vessel, and the glue drain holes are directly opposite the arc-shaped reinforcing ribs. S3. Grinding and rust removal of the outer shell of the vessel body with arc-shaped reinforcing ribs and glue drain holes: Grinding and rust removal of the outer shell of the vessel body with arc-shaped reinforcing ribs and glue drain holes through sandblasting. S4. Fabrication of PTFE lining: Select polytetrafluoroethylene (PTFE) sheets and fabricate a PTFE lining that matches the shape and size of the vessel shell. S5. The prepared PTFE liner is subjected to sodium treatment. After the sodium treatment is completed, the PTFE liner is cleaned and dried. S6. Assembly of PTFE liner and vessel shell: Apply adhesive evenly to the inner wall of the vessel shell, ensuring that the adhesive is applied evenly and to a consistent thickness; place the sodium-treated PTFE liner inside the vessel shell and use supports to hold the PTFE liner open, so that the PTFE liner fits snugly against the inner wall of the vessel shell; perform flanging treatment on the fitted PTFE liner, and after the flanging treatment is completed, remove all supports; S7. Use a sealing device to seal both ends of the vessel shell with the PTFE liner. S8. Bonding and fixing of PTFE liner to vessel shell: Steam at 2.5-3.5 MPa is introduced into the vessel shell assembled with PTFE liner through the steam inlet pipe of the sealing device, and the temperature is maintained at 110-130℃ for 1-3 hours. The PTFE liner is uniformly squeezed towards the inner wall of the vessel shell by the steam pressure. During the process of the PTFE liner moving towards the inner wall of the vessel shell, the adhesive applied to the inner wall of the vessel shell is squeezed. The larger gap of the PTFE liner is supported by the arc-shaped reinforcing ribs, so that the adhesive applied to the inner wall of the vessel shell and the air between the PTFE liner and the vessel shell are gathered into the larger gap and discharged from the glue discharge hole below the arc-shaped reinforcing ribs. The adhesive wraps around the arc-shaped reinforcing ribs. After the glue discharge is carried out for a preset time, an air-free adhesive layer is formed between the inner wall of the vessel shell, the PTFE liner and the arc-shaped reinforcing ribs. The adhesive layer is used to fix the PTFE liner to the inner wall of the vessel shell and the arc-shaped reinforcing ribs. After the S9 PTFE liner is bonded and fixed to the outer shell of the vessel, the glue drain hole is sealed from the outside of the vessel shell to finally obtain a large-diameter steel-lined PTFE distillation vessel.

2. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 1, characterized in that, The large-diameter steel-lined PTFE distillation vessel includes an outer shell and a PTFE liner. An arc-shaped reinforcing rib is provided on the inner wall of the outer shell, and multiple adhesive drain holes are provided on the outer shell, directly opposite the arc-shaped reinforcing ribs. An inwardly protruding covering layer is provided on the PTFE liner, the height of which is adapted to the arc-shaped reinforcing ribs. The covering layer surrounds and covers the arc-shaped reinforcing ribs. A gel layer exists between the outer shell and the PTFE liner. One side of the gel layer is bonded to the inside of the outer shell and extends into the adhesive drain hole, forming a cylindrical plug. The other side of the gel layer is bonded to the outer wall of the PTFE liner. The arc-shaped reinforcing ribs are fixedly connected to the inner wall of the outer shell by equally spaced weld joints. A gap exists between the arc-shaped reinforcing ribs and the inner wall of the outer shell. The gel layer passes through the gap between the arc-shaped reinforcing ribs and the inner wall of the outer shell and covers the arc-shaped reinforcing ribs, thus using the gel layer and the arc-shaped reinforcing ribs to stably fix the outer shell and the PTFE liner.

3. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 2, characterized in that, A cylindrical plug extends into the glue discharge hole and fills one section of the hole. A plug is installed on the other section of the glue discharge hole that is not filled by the cylindrical plug. The cylindrical plug and the plug together seal the glue discharge hole. The cylindrical plug is close to the inner wall of the vessel shell, and the plug is close to the outer wall of the vessel shell. The plug and the glue discharge hole are welded together in a sealed connection.

4. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 2, characterized in that, The outer wall of the coating layer forms a groove, the cross-section of which matches the cross-section of the arc-shaped reinforcing rib, and the thickness of the coating layer is the same as the thickness of the PTFE liner near both ends of the vessel shell.

5. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 2, characterized in that, The inner wall of the vessel body shall be provided with at least one arc-shaped reinforcing rib, and the number of the covering layers shall be consistent with the number of the arc-shaped reinforcing ribs.

6. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 1, characterized in that, The outer shell of the vessel body is provided with a first flange and a second flange at both ends, respectively. The first flange is provided with a plurality of first fixing holes, and the second flange is provided with a plurality of second fixing holes. The two ends of the PTFE liner are provided with a first flange and a second flange. The first flange covers the upper side of the first flange, and the outer edge of the first flange is close to the first fixing hole. The second flange covers the lower side of the second flange, and the outer edge of the second flange is close to the second fixing hole. A plurality of first reinforcing ribs are provided between the outer wall of the vessel body and the first flange, and the plurality of first reinforcing ribs are arranged around the outer wall of the vessel body. A second reinforcing rib is provided between the outer wall of the vessel body and the second flange, and the second reinforcing rib is arranged around the outer wall of the vessel body.

7. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 1, characterized in that, The sealing device described in step S7 includes a first sealing head, a second sealing head, and a connecting rod. The middle position of the first sealing head is fixedly connected to the first end of the connecting rod, and the middle position of the second sealing head is detachably connected to the second end of the connecting rod. The edge of the first sealing head is provided with multiple first through holes, and the edge of the second sealing head is provided with multiple second through holes. A steam inlet pipe is provided on either the first or second sealing head.

8. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 7, characterized in that, A pressure gauge is installed on the first or second sealing head. A third through hole is provided in the middle of the second sealing head. The first end of the connecting rod is fixedly connected to the first sealing head. The connecting rod is provided with an external thread of a predetermined length, and the external thread of the predetermined length is close to the second end of the connecting rod. The second end of the connecting rod passes through the third through hole of the second sealing head, and the external thread of the predetermined length is close to the third through hole of the second sealing head. The external thread of the predetermined length is located between the second sealing head and the second end of the connecting rod. The second end, which passes out of the third through hole of the second sealing head, passes through the sealing sleeve connecting rod in sequence to install a sealing sleeve and a fastening nut. The outer diameter of the sealing sleeve is matched with the diameter of the third through hole, and the inner diameter of the sealing sleeve is matched with the diameter of the connecting rod. The fastening nut pushes the sealing sleeve closer to the third through hole of the second sealing head by engaging with the external thread of the connecting rod, so that the sealing sleeve is inserted into the annular gap between the third through hole of the second sealing head and the connecting rod. The outer side of the sealing sleeve is in sealing contact with the third through hole of the second sealing head, and the inner side of the sealing sleeve is in sealing contact with the connecting rod.

9. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 8, characterized in that, A fourth through hole is provided at the middle position of the first sealing head. One end of the connecting rod passes through the fourth through hole and is sealed and welded to the first sealing head. Multiple reinforcing ribs are provided between the first sealing head and the connecting rod. The reinforcing ribs are distributed on either side of the first sealing head and are distributed around the connecting rod.

10. The method for preparing a large-diameter steel-lined PTFE distillation vessel as described in claim 9, characterized in that, The sealing sleeve is a conical sealing sleeve, meaning that the thickness of the outer wall of the sealing sleeve gradually decreases at one end and gradually increases at the other end.

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