Combined tower plate structure for ethylene glycol rectifying tower

Abstract

The utility model provides a combined tower plate structure for an ethylene glycol rectifying tower, which is arranged below a filler of the rectifying tower and comprises a liquid collector and a plurality of layered tower plate bodies, the tower plate bodies are detachably connected with the inner wall of the rectifying tower, manholes are arranged above the tower plate bodies of the rectifying tower, and the manholes are communicated with the liquid collector. The tower plate body can be taken out from the rectifying tower through the manhole; the tower plate body comprises a sieve plate tower plate and a tongue-shaped tower plate; the sieve-plate tower plate is arranged in the middle of a tower plate arranged on the rectifying tower, the tongue-shaped tower plates are arranged on two sides of the sieve-plate tower plate, an overflow weir is formed on the left side or the right side of a tower plate body, and a stabilizing area is arranged between the overflow weir and the tower plate body; a plurality of sieve pores are formed in the tower plate body. According to the utility model, cokes on the tower plate can be cleaned more easily, and the difficulty of cleaning blocked substances is effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the field of distillation towers, in particular to a combined tower plate structure for an ethylene glycol distillation tower. Background Art

[0002] The chemical method for recycling waste PET is to use PET as raw material, depolymerize and react with ethylene glycol under the action of a catalyst to generate an intermediate product BHET (diethylene glycol terephthalate), and BHET further undergoes an ester exchange reaction with methanol to generate DMT (dimethyl terephthalate) and ethylene glycol. The ethylene glycol liquid produced in this process contains the intermediate product BHET, the reaction product DMT, the by-product HMT (ethylene glycol terephthalate) and impurities that cannot be removed from the reaction raw materials. Therefore, refining ethylene glycol to improve the purity of ethylene glycol is beneficial to the depolymerization reaction in the process, thereby improving the efficiency of recycling waste PET;

[0003] The purity of unrefined ethylene glycol in the process of recycling waste PET is low and is accompanied by many impurities. This is mainly because the raw material PET comes from waste beverage bottles, waste cloth, waste textiles, etc. In order to ensure the recovery rate of the reaction product DMT, the raw material will be pretreated before the reaction, and a filtration section will be set up in the process to remove solid impurities such as cotton and linen. However, it is still inevitable that there will be residual dyes, oligomers, by-products in the reaction process such as HMT and elements in the raw materials that cannot be removed by physical means such as DMI (dimethyl isophthalate). These impurities will remain in the ethylene glycol-containing liquid. The use of conventional distillation towers will cause a certain degree of blockage and coking at the bottom of the tower, affecting the distillation process. Utility Model Content

[0004] In view of this, the utility model aims to propose a combined tower plate structure for an ethylene glycol distillation tower, which can effectively reduce the difficulty of cleaning blocked materials.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A combined tray structure for an ethylene glycol distillation tower, arranged at the lower part of a stripping section of the distillation tower, comprising a plurality of tray bodies arranged in layers, wherein the tray bodies are detachably connected to the inner wall of the distillation tower, and a manhole is provided on the distillation tower, through which the tray bodies can be taken out of the distillation tower;

[0007] The tower plate body comprises a sieve plate and a tongue-shaped tower plate; the sieve plate is arranged in the middle part of the tower plate body of the distillation tower, and the tongue-shaped tower plate is arranged on both sides of the sieve plate.

[0008] An overflow weir is formed on the left or right side of the tower plate body, and a stable zone is arranged between the overflow weir and the tower plate body; and a plurality of sieve holes are arranged on the tower plate body.

[0009] Furthermore, the number of the tower plate body is 3 layers, the first layer of the tower plate body, the overflow weir is arranged on the left side of the sieve plate tower plate, the second layer of the tower plate body, the overflow weir is arranged on the right side of the sieve plate tower plate, and the third layer of the tower plate body, the overflow weir is arranged on the left side of the sieve plate tower plate.

[0010] Furthermore, the thickness of the tray body is 2-3 mm; the middle sieve tray is rectangular and can be divided into three areas, and the tongue-shaped trays on both sides are divided into two areas;

[0011] The widths of the three regions of the sieve plate are 500mm, 500mm and 340mm respectively; the width of the tongue-shaped plate is 430mm.

[0012] Furthermore, the length of the overflow weir is Lw=1735-1780mm, and the width is Wd=350mm; the width of the stable zone is Ws=125-150mm; an invalid zone is provided at the edge of the tower plate body, and the width of the invalid zone is Wc=50-70mm.

[0013] Further, the sieve hole of the sieve plate is a No. 1 sieve hole, which is circular and has a diameter of d0 = 25-28 mm, and the hole center distance t1 of the No. 1 sieve hole is 2 times the hole diameter;

[0014] The sieve holes of the tongue-shaped tower plate are used as No. 2 sieve holes, which are tongue-shaped, with a hole spacing t3=72-76mm, a spacing t2=62-66mm between each row of tongue holes, t4=35-40mm at the opening, t5=20-25mm, a radius R1=17.5-20mm at the tongue-shaped arc, and the number of openings n=77-105 on each tongue-shaped tower plate.

[0015] Furthermore, the plate spacing between the three tower plate bodies is 500 mm, the overflow weir height hw is set to 50 mm, and the bottom gap height of the downcomer h0=40 mm.

[0016] Furthermore, a tongue piece is provided above each No. 2 sieve hole, and the tongue piece has an inclination angle α=15°-23°.

[0017] Compared with the prior art, the combined tray structure for an ethylene glycol distillation tower described in the utility model has the following advantages:

[0018] (1) The utility model provides a combined tray structure for an ethylene glycol distillation tower, which can more easily clean the coke on the tray and effectively reduce the difficulty of cleaning the clogging material.

[0019] (2) The utility model discloses a combined tower plate structure for an ethylene glycol distillation tower. The optimized tower blockage period is extended by about 90 days compared with the original tower, and the cleaning time of the tower can be shortened by 115-120 minutes, which effectively reduces the difficulty of cleaning coke and improves the distillation efficiency of the distillation tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of a combined tray structure for an ethylene glycol distillation tower according to an embodiment of the utility model;

[0022] Figure 2 This is a schematic diagram of the tower plate layout described in an embodiment of the utility model;

[0023] Figure 3 This is a schematic diagram of the opening of the tower plate according to the embodiment of the utility model;

[0024] Figure 4 It is a partial enlarged schematic diagram of the opening of the tower plate described in the embodiment of the utility model;

[0025] Figure 5 This is a schematic diagram of the angle of the sieve hole tongue piece according to the embodiment of the utility model;

[0026] Figure 6 This is a schematic diagram of the distillation process of ethylene glycol using a distillation tower described in an embodiment of the utility model.

[0027] Description of reference numerals:

[0028] 1. Tower plate body; 11. Sieve plate tower plate; 12. Tongue-shaped tower plate; 13-17. Sieve hole area; 18. Liquid receiving area; 2. Overflow weir; 3. Stable area. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the 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, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0033] A combined tray structure for an ethylene glycol distillation tower, arranged at the lower part of a stripping section of the distillation tower, comprises a plurality of tray bodies 1 arranged in layers, the tray bodies 1 are detachably connected to the inner wall of the distillation tower, a manhole is arranged above the tray of the distillation tower, and the tray body 1 can be taken out of the distillation tower through the manhole;

[0034] The tray body 1 comprises a sieve tray 11 and a tongue-shaped tray 12; the sieve tray 11 is arranged in the middle part of the tray body of the distillation tower, and the tongue-shaped tray 12 is arranged on both sides of the sieve tray 11.

[0035] An overflow weir 2 is formed on the left or right side of the tray body 1, and a stable zone 3 is provided between the overflow weir 2 and the tray body 1; a plurality of sieve holes are provided on the tray body 1, and a plurality of sieve holes are provided on the tray body 1. Figure 3 The middle numbers 13-17 are the sieve hole areas, and 18 is the liquid receiving area.

[0036] The main function of the tower plate is to reduce the coke residue in the tower kettle, so a sieve plate tower plate 11 with a small pressure drop is used. In order to reduce the entrainment of rising gas mist, the two tower plates on the edge are tongue-shaped tower plates 12, which can play a role in guiding the gas.

[0037] Preferably, the number of the tower plate body 1 is 3 layers, the first layer of the tower plate body 1, the overflow weir 2 is arranged on the left side of the sieve plate tower plate 11, the second layer of the tower plate body 1, the overflow weir 2 is arranged on the right side of the sieve plate tower plate 11, and the third layer of the tower plate body 1, the overflow weir 2 is arranged on the left side of the sieve plate tower plate 11.

[0038] Preferably, the thickness of the tray body 1 is 2-3 mm; the middle sieve tray 11 is rectangular and can be divided into three areas, and the tongue-shaped trays 12 on both sides are divided into two areas;

[0039] The widths of the three regions of the sieve plate tray 11 are 500 mm, 500 mm and 340 mm respectively; the width of the tongue-shaped tray 12 is 430 mm.

[0040] Preferably, the length of the overflow weir 2 is Lw=1735-1780mm, and the width is Wd=350mm; the width of the stable zone 3 is Ws=125-150mm; an invalid zone is provided at the edge of the tower plate body 1, and the width of the invalid zone is Wc=50-70mm; such a size design can prevent the gas phase from leaking into the upper tower plate from the downcomer.

[0041] Preferably, the sieve hole of the sieve plate 11 is a No. 1 sieve hole, which is circular and has a diameter of d0=25-28 mm; the hole center distance of the conventional sieve plate 11 is 3-4 times the aperture, but due to the vacuum operation in the tower, in order to reduce the pressure drop at the plate, the hole center distance of the No. 1 sieve hole is reduced to t1, which is 2 times the aperture;

[0042] In this way, the opening rate ψ can be increased to 23%-25%, and the total area of ​​the sieve holes on the designed single tray is A0 = 0.345-0.675m 2 The opening rate of the tongue-shaped plate still needs to be maintained at 23%-25%, so the area of ​​the tongue-shaped hole on a single plate is 0.115-0.125m 2 ,

[0043] The diameter of the sieve holes in industry is mostly 3-8 mm, but since the main function of the tower plate installed here is to prevent the tower kettle from being blocked by coking, the sieve hole size is selected to be d0 = 25-28 mm in diameter;

[0044] The sieve hole of the tongue-shaped tray 12 is the second sieve hole, which is tongue-shaped, with a hole spacing t3 = 72-76 mm, a spacing t2 = 62-66 mm between each row of tongue holes, t4 = 35-40 mm at the opening, t5 = 20-25 mm, and a radius R1 = 17.5-20 mm at the tongue arc. Therefore, the area A of each tongue hole is 1.18 × 10 -3 -1.628×10 -3 m 2The number of openings on each tongue-shaped tower plate 12 is n=77-105.

[0045] Preferably, the plate spacing of the three tray bodies 1 is 500 mm. Although a concave liquid receiving tray is often used in a tower with a larger diameter, a flat liquid receiving tray is used in this design to avoid blockage by liquid polymerization; in order to maintain the vacuum degree in the tower while leaving a certain amount of liquid on the tray;

[0046] The height hw of overflow weir 2 is set to 50 mm, and the bottom gap height of downcomer h0 = 40 mm;

[0047] After optimization, the pressure drop of each tower plate is about 230-250Pa, which is 47%-50% lower than that of conventional tower plates. This optimization method can ensure that the pressure drop in the tower is maintained at a low value while making it easier to clean the coking on the tower plates.

[0048] Preferably, a tongue is provided above each No. 2 sieve hole, and the tongue has an inclination angle of α=15°-23°; the tongue opening is as follows: Figure 5 As shown, this can effectively prevent the rising airflow from accelerating the liquid phase on the plate to flow toward the downcomer. Through field tests, it can be determined that when the tongue inclination angle α=15°-23°, the mist entrainment amount can be guaranteed to be at a minimum value.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A combined tray structure for an ethylene glycol distillation tower, arranged at the lower part of the stripping section of the distillation tower, characterized in that: It comprises a plurality of layered tray bodies, the tray bodies are detachably connected to the inner wall of the distillation tower, and a manhole is provided above the tray body of the distillation tower, through which the tray body can be taken out of the distillation tower; The tower plate body includes a sieve plate and a tongue-shaped tower plate; the sieve plate is arranged in the middle part of the tower plate body of the distillation tower, and the tongue-shaped tower plate is arranged on both sides of the sieve plate. An overflow weir is formed on the left or right side of the tower plate body, and a stable zone is arranged between the overflow weir and the tower plate body; and a plurality of sieve holes are arranged on the tower plate body.

2. The combined tray structure for an ethylene glycol distillation tower according to claim 1, characterized in that: The number of the tower plate bodies is 3. For the first tower plate body, the overflow weir is arranged on the left side of the sieve plate tower plate, for the second tower plate body, the overflow weir is arranged on the right side of the sieve plate tower plate, and for the third tower plate body, the overflow weir is arranged on the left side of the sieve plate tower plate.

3. The combined tray structure for an ethylene glycol distillation tower according to claim 2, characterized in that: The thickness of the tray body is 2-3 mm; the sieve tray in the middle is rectangular and can be divided into three areas, and the tongue-shaped trays on both sides are divided into two areas; The widths of the three regions of the sieve plate are 500mm, 500mm and 340mm respectively; the width of the tongue-shaped plate is 430mm.

4. The combined tray structure for an ethylene glycol distillation tower according to claim 2, characterized in that: The length of the overflow weir is Lw=1735-1780mm, and the width is Wd=350mm; the width of the stable zone is Ws=125-150mm; an invalid zone is provided at the edge of the tower plate body, and the width of the invalid zone is Wc=50-70mm.

5. The combined tray structure for an ethylene glycol distillation tower according to claim 1, characterized in that: The sieve hole of the sieve plate tower is the No. 1 sieve hole, which is circular with a diameter of d0 = 25-28 mm, and the hole center distance of the No. 1 sieve hole is 2 times the hole diameter; The sieve holes of the tongue-shaped tower plate are used as No. 2 sieve holes, which are tongue-shaped, with a hole spacing t3=72-76mm, a spacing t2=62-66mm between each row of tongue holes, t4=35-40mm at the opening, t5=20-25mm, a radius R1=17.5-20mm at the tongue-shaped arc, and the number of openings n=77-105 on each tongue-shaped tower plate.

6. The combined tray structure for an ethylene glycol distillation tower according to claim 1, characterized in that: The plate spacing of the three tower plate bodies is 500 mm, the overflow weir height hw is set to 50 mm, and the bottom gap height of the downcomer h0=40 mm.

7. The combined tray structure for an ethylene glycol distillation tower according to claim 5, characterized in that: A tongue is provided above each No. 2 sieve hole, and the tongue has an inclination angle of α=15°-23°.

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