CN219423762U - Tray and stripping tower - Google Patents

Abstract

The utility model belongs to the technical field of polyvinyl chloride production. In view of the problem that PVC particles are stuck to the bottom of a tray to influence the quality of a finished product in the existing stripping tower, the utility model discloses the tray and the stripping tower, wherein the sieve holes of the tray structure comprise a first section and a second section which are communicated with each other; wherein the second section is conical; the second segment has a terminal cross-sectional area that is greater than a beginning cross-sectional area of the first segment. The utility model also discloses a stripping tower which is provided with a plurality of layers of trays disclosed by the utility model, so that the problem that PVC particles are stuck to the bottom of the trays in the stripping tower, thereby influencing the quality of a finished product is solved.

Description

Tray and stripping tower

Technical Field

The utility model belongs to the technical field of polyvinyl chloride production, and particularly relates to a tray and a stripping tower.

Background

The most commonly used production method of polyvinyl chloride (hereinafter referred to as PVC) is water-phase suspension method, namely, deionized water and vinyl chloride monomer are added, auxiliary agent and initiator are added, polyvinyl chloride is produced by reaction at specific temperature and pressure in a polymerization kettle, and the produced polyvinyl chloride is in water-phase suspension state. The gaps of the PVC particles contain vinyl chloride monomer (VCM for short), and the PVC particles are possibly still contained with VCM after being dried, so that the use of PVC in some fields is affected due to the fact that the VCM monomer has great toxicity. Thus, the stripper is one of the most critical equipment in the PVC production process for removing VCM from the PVC slurry, reducing the VCM content to 5 μg/g.

At present, a stripping tower adopted by the company is a sieve-plate type stripping tower, PVC slurry with higher VCM content enters from the top of the stripping tower, and the slurry flows from the top to the bottom along the first layer of tower plates; steam enters from the bottom of the stripping tower, rises from the holes of the tower plates from bottom to top, completes heat and mass transfer with the descending slurry on each layer of tower plates, and desorbs VCM remained on the surface and inside of the resin particles, and the steam and the desorbed VCM are discharged from the top of the stripping tower; the discharged VCM and steam enter a recovery system after passing through a tower top condenser, and the slurry with the VCM removed is conveyed from the bottom of the stripping tower to be dried.

However, the sieve holes of the trays of the existing stripping tower are straight-through, and when PVC slurry vertically flows down to the bottoms of the holes along the sieve holes, part of PVC particles are stuck to the bottoms of the trays; the PVC particles can be heated for a long time by high-temperature steam Huang Fahei, and can fall down and be mixed into clean PVC slurry when being impacted in the process of greatly lifting load, so that black and yellow spots are formed on the PVC finished product, and the quality of the PVC finished product is affected.

Disclosure of Invention

In view of the problem that the quality of a finished product is affected due to the fact that PVC particles adhere to the bottom of a tray in the existing stripping tower, the utility model aims to provide the tray which can prevent the PVC particles from adhering to the bottom of the tray and is beneficial to improving the quality of PVC products.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

a tray provided with a sieve pore, wherein the sieve pore comprises a first section and a second section which are communicated with each other; wherein the second section is conical.

In one of the technical solutions disclosed in the present utility model, the axial center line of the first section and the axial center line of the second section coincide.

In one of the technical schemes disclosed by the utility model, the second section is formed by taking the tail end of the first section as a substrate and extending the tail end downwards in a gradually expanding manner.

In one of the technical solutions disclosed in the present utility model, the first section is tapered.

In one of the technical schemes disclosed by the utility model, the first section is straight-through; the second segment has a terminal cross-sectional area that is greater than a beginning cross-sectional area of the first segment.

In one of the technical solutions disclosed in the present utility model, the length of the first section is equal to the length of the second section.

In one of the technical solutions disclosed in the present utility model, the end diameter of the second section is 8±1mm.

In one of the technical schemes disclosed by the utility model, the diameter of the initial end of the first section is 5+/-1 mm.

In one of the technical schemes disclosed by the utility model, the cross section of the sieve holes is circular.

The utility model also discloses a stripping tower which comprises a plurality of layers of trays according to any one of the technical schemes.

From the above description, the beneficial effects of the utility model are as follows:

because the second section can be regarded as the reducing pipe, the resistance loss is great, and the resistance loss is unrecoverable, thereby lead to the static pressure energy at the exit to be reduced in the whole, thereby reducible PVC thick liquids lateral diffusion in exit, simultaneously, the exit pressure of second section is higher than the entry pressure of second section, make things convenient for PVC thick liquids to flow out the second section, this two cooperation, avoid appearing PVC thick liquids lateral flow and lead to PVC granule to glue the bottom of gluing at the tray, thereby influence the problem of finished product quality.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the technical descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a prior art tray.

Fig. 2 is a tray of the present utility model.

Reference numerals: 1-original tray; 11-opening holes; 2-new tray; 3-sieve pores; 31-a first section; 32-second stage.

Detailed Description

Hereinafter, only certain exemplary embodiments are briefly described. As will be recognized by those of skill in the pertinent art, the described embodiments may be modified in various different ways without departing from the spirit or scope of the present utility model. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

In the description of the present utility model, 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", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model.

Furthermore, in the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

Embodiments of the present utility model will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the openings 11 of the original tray 1 of the stripping tower are through-type with a constant diameter, when the PVC slurry flows down to the bottom of the holes along the Kong Chui tower, due to the large outlet resistance, part of the slurry flows laterally to cause PVC particles to adhere to the bottom of the tray, and in the long-time working process, the PVC slurry falls into the PVC slurry from which VCM is removed, thereby forming black and yellow dots in the PVC product, and affecting the quality of the product.

In order to solve the above-mentioned problems, an embodiment of the present utility model discloses a new tray 2, the structure of which is shown in fig. 2, wherein a sieve opening 3 is formed on the new tray 2, the sieve opening 3 includes a first section 31 and a second section 32 which are mutually communicated, and the first section 31 and the second section 32 may be disposed on the same central axis or not. When the stripper provided with new trays 2 is in operation, PVC slurry flows from the first section 31 into the new trays 2 and then from the second section 32.

The second section 32 is tapered, i.e. the longitudinal section of the second section 32 is trapezoidal; the cross-sectional area of the end of the second section 32 is greater than the cross-sectional area of the beginning of the first section 31.

According to the flow mechanics, compared with the original tray 1 shown in fig. 1, when the PVC slurry flows to the second section 32 of the new tray 2, the second section 32 converts the kinetic energy of the PVC slurry into static pressure energy, so that the pressure at the outlet is high, the PVC slurry is conveniently discharged, and the problem that the quality of a finished product is affected because PVC particles are adhered to the bottom of the tray 2 is avoided.

More specifically, in some embodiments, the second section 32 is formed by using the end edge of the first section 31 as a base and extending gradually downwards, and the first section 31 and the second section 32 are preferably disposed on the same central axis. The purpose of this is to reduce the loss of resistance between the first segment 31 and the second segment 32.

It is to be understood that in the present embodiment, the shape and structure of the first section 31 are not required, and the first section 31 may be straight, tapered, inverted or the like.

More specifically, the cross-sections of the first and second sections 31, 32 are circular, rectangular, triangular lines, or the like.

Example 1

As a specific implementation of the above embodiment, in this embodiment, the first section 31 is preferably a straight-through type, and the cross sections of the first section 31 and the second section 32 are preferably circular.

Specifically, the thickness of the new tray 2 is 4mm, the diameter of the first section 31 is 5mm, the diameter of the end of the second section 32 is 8mm, and the lengths of the first section 31 and the second section 32 are equal.

Comparative example 1

In the actual production of PVC from this company, the original tray 1 of the stripping column has a thickness of 4mm, the openings 11 are straight-through type with a circular cross section and a diameter of 8 mm.

From the fluid mechanics, the total mechanical energy of the PVC slurry is constant,

total mechanical energy = kinetic energy + hydrostatic energy + potential energy + drag loss.

The potential energy at the outlet is equal compared to that of example 1 and comparative example 1; the first section 31 of example 1 has a small diameter and a large flow rate, and the second section 32 can be regarded as a reducer, which both result in a large resistance loss of example 1, but the resistance loss is not recoverable, so that the static pressure energy at the outlet is reduced compared with that of comparative example 1 as a whole, and the lateral diffusion of the PVC slurry at the outlet can be reduced, and the outlet pressure of the second section 32 is higher than the inlet pressure of the second section 32, so that the PVC slurry flows out of the second section 32, and the two sections cooperate, so that the problem that the PVC particles are stuck to the bottom of the tray and the quality of the finished product is affected is avoided.

The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the utility model, and is not meant to limit the scope of the utility model, but to limit the utility model to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the utility model are intended to be included within the scope of the utility model.

Claims (10)

1. A tray provided with a mesh, wherein the mesh comprises:

a first section and a second section in communication with each other;

wherein the second section is conical.

2. The tray of claim 1 wherein the central axis of the first section and the central axis of the second section coincide.

3. The tray of claim 1 wherein said second section is downwardly divergent from said first section at its end.

4. A tray according to claim 3, wherein the first section is tapered.

5. A tray according to claim 1 or 3, wherein the first section is straight-through; the second segment has a terminal cross-sectional area that is greater than a beginning cross-sectional area of the first segment.

6. The tray of claim 5 wherein the length of said first section and the length of said second section are equal.

7. The tray of claim 6, wherein the second section has a terminal diameter of 8±1mm.

8. The tray of claim 7 wherein the first section has a start diameter of 5±1mm.

9. The tray of claim 1 wherein said mesh is circular in cross-section.

10. A stripper comprising a plurality of layers of trays according to any of claims 1 to 9.