A flat-plate membrane internal for an absorption tower and the absorption tower itself.

Abstract

This invention discloses a flat-plate membrane internal for an absorption tower and an absorption tower. The flat-plate membrane internal includes several vertically arranged flat plates and a support assembly for supporting and fixing the plates; a flow channel is formed between adjacent plates; the flat-plate membrane internal includes the following three structures: (I) the surface of the plate is provided with continuous raised or continuous groove patterns; the support assembly is an external frame; (II) the surface of the plate is provided with discontinuous raised patterns; the support assembly is an external frame; (III) the support assembly is several connecting columns, and adjacent plates are supported and fixed by staggered connecting columns. The fixed flow channel in the structure of this flat-plate membrane internal restricts the lateral movement of gas molecules, achieving uniform gas-liquid countercurrent contact. At the same time, by optimizing the surface geometry and arrangement of the plates, as well as the form of the support assembly, the gas-liquid contact area is further increased and the gas-liquid contact time is extended, thereby improving the gas-liquid mass transfer efficiency in the tower, reducing the pressure drop in the tower, and reducing system energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation and mass transfer equipment technology, specifically relating to a flat-plate membrane internal for an absorption tower and an absorption tower. Background Technology

[0002] In many chemical industrial processes, absorption towers are the core equipment for separating and purifying gas mixtures. Traditional absorption towers, such as packed towers or plate towers, are widely used in industrial applications, but they generally suffer from the following defects: uneven distribution of absorbent, resulting in insufficient gas-liquid contact and low mass transfer efficiency; high flow resistance between the gas and liquid phases, high system pressure drop, and significant energy consumption; and easy clogging of packing or trays, leading to high maintenance costs.

[0003] Existing technologies have already provided some solutions to the above problems:

[0004] CN222738845U discloses a desulfurization device using a rotary jet assembly. This device effectively solves the clogging problem of traditional packing layers by preventing reaction products from remaining in the tower, thus improving the stability of long-term operation. However, although the rotary jet assembly in this solution solves the clogging problem, the contact time between the gas and liquid phases is relatively short, and the liquid film morphology is difficult to control, resulting in limited potential for improving mass transfer efficiency and making it difficult to meet increasingly stringent requirements for deep purification. Summary of the Invention

[0005] Addressing the technical bottlenecks of existing absorber internals, such as uneven gas-liquid distribution, insufficient effective mass transfer area, and excessive system pressure drop, this invention provides a novel flat-plate membrane internal and absorber tower. The aim is to achieve efficient gas-liquid mass transfer while reducing system energy consumption through optimized absorber internals, thus meeting the application requirements for deep gas purification.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A first aspect of the present invention is to provide a flat plate membrane internal for an absorption tower, the flat plate membrane internal comprising a plurality of vertically arranged flat plates and a support assembly for supporting and fixing the flat plates; a flow channel is formed between adjacent flat plates;

[0008] The flat membrane internals include the following three structures:

[0009] (I) The surface of the plate is provided with continuous raised or continuous groove patterns, including sawtooth raised patterns, teardrop raised patterns, horizontal grooves and vertical grooves; the support component is an external frame;

[0010] (II) The surface of the flat plate is provided with discontinuous raised textures, including staggered hemispherical protrusions and aligned hemispherical protrusions; the support component is an external frame;

[0011] (III) The support component consists of several connecting columns, and adjacent plates are supported and fixed by staggered connecting columns.

[0012] In some embodiments, the thickness of a single plate is 1 / 120 to 1 / 60 of the inner diameter of the absorption tower, and the ratio of the thickness of a single plate to the distance between two adjacent plates is 1 / 4 to 1; the overall height of the plate membrane internals accounts for 1 / 4 to 1 / 2 of the height of the absorption tower.

[0013] In some embodiments, the plate is made of a hydrophilic and corrosion-resistant material; the hydrophilic and corrosion-resistant material is selected from one or more of stainless steel 304, stainless steel 316L, duplex stainless steel, polypropylene, polyvinyl chloride and alumina ceramic.

[0014] In some embodiments, the flat sheet membrane internals are installed entirely inside the absorption tower, and the overall outer diameter of the flat sheet membrane internals is slightly smaller than the inner diameter of the absorption tower, which facilitates later maintenance, cleaning, and component replacement.

[0015] In some embodiments, in structure (I), the ratio of the horizontal width of the serrated protrusion or teardrop protrusion to the thickness of the plate is 1 / 4-1, and the ratio of its vertical height to the thickness of the plate is 1 / 4-1.

[0016] In some embodiments, in structure (I), the ratio of the depth of the horizontal groove and the vertical groove to the thickness of the plate is 1 / 4-1 / 2; the ratio of the width of the horizontal groove or the vertical groove to the thickness of the plate is 1 / 2-3 / 2; and the ratio of the spacing between adjacent grooves to the thickness of the plate is 1 / 2-3 / 2.

[0017] In some embodiments, in structure (II), the ratio of the radius of the hemispherical protrusion to the thickness of the plate is 1 / 4-1; when staggered, the ratio of the distance between adjacent hemispherical protrusions to the thickness of the plate is 1 / 3-3 / 2; when aligned, the ratio of the distance between adjacent hemispherical protrusions to the thickness of the plate is 1 / 3-3 / 2.

[0018] In some embodiments, in structure (Ⅲ), the ratio of the length of the connecting post to the thickness of the plate is 1.2-2; the ratio of the diameter of the connecting post to the thickness of the plate is 1 / 2-4; and the spacing between adjacent connecting posts is 1-8 times the thickness of the plate.

[0019] In some embodiments, the outer frame is provided with a slot adapted to the size of the plate, and the plate is inserted into the slot of the outer frame for fixing; the frame structure is a single-layer or multi-layer frame combination, and when a multi-layer frame is used, adjacent frames are supported and fixed by fixing columns.

[0020] The ratio of the overall height of the external frame to the height of a single plate is 1 / 3-1.

[0021] A second aspect of the present invention is to provide an absorption tower employing the above-described flat membrane internals, the absorption tower comprising a tower body, a liquid distributor and a flat membrane internals arranged sequentially inside the tower body in a vertical position, wherein the upper part of the tower body is provided with an absorbent inlet and a gas phase outlet, and the lower part is provided with an absorbent outlet and a gas phase inlet.

[0022] The liquid distributor is either a gravity distributor or a pressure distributor.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The flat plate membrane internal structure of the present invention forms a fixed flow channel through several vertically arranged flat plates, which restricts the lateral movement of gas molecules and achieves uniform gas-liquid countercurrent contact. At the same time, by optimizing the surface geometry and arrangement of the flat plates, as well as the form of the support components, the gas-liquid contact area and the gas-liquid contact time can be further increased, thereby improving the gas-liquid mass transfer efficiency in the tower, reducing the pressure drop in the tower, and reducing the system energy consumption.

[0025] (2) Compared with the traditional absorption tower structure, the absorption tower using the flat sheet membrane internals of the present invention has an open flow channel that is less prone to clogging and is suitable for a wider range of working conditions. The flat sheet membrane internals are modular and detachable, which facilitates subsequent cleaning, maintenance and replacement. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an absorption tower that uses flat-sheet membrane internals.

[0027] Figure 2 a and Figure 2 Figures b and c are respectively a schematic diagram and a top view of the internal components of the flat sheet membrane.

[0028] Figure 3 a and Figure 3 b are the front view and side view of a flat plate with serrated protrusions on its surface, respectively.

[0029] Figure 4 a and Figure 4 b are the front view and side view of a flat plate with teardrop-shaped protrusions on its surface, respectively.

[0030] Figure 5 a and Figure 5 The figures b are the side view and the front view of a flat plate with horizontal grooves on its surface, respectively.

[0031] Figure 6 a and Figure 6 The top and front views of the flat plate with vertical grooves on its surface are shown in Figures b and c, respectively.

[0032] Figure 7This is a magnified view of a flat plate with teardrop-shaped protrusions on its surface.

[0033] Figure 8 a and Figure 8 The figures b are the front view and side view of a flat plate with staggered hemispherical protrusions on its surface.

[0034] Figure 9 a and Figure 9 The figures b are the front view and side view of a flat plate with aligned hemispherical protrusions on its surface.

[0035] Figure 10 a and Figure 10 The figures b are the front view and side view of the flat membrane internal component, which is supported and fixed by the connecting column.

[0036] In the picture:

[0037] 10-Tower body; 11-Absorbent inlet; 12-Gas inlet; 13-Absorbent outlet; 14-Gas outlet;

[0038] 20 - Liquid distributor;

[0039] 30-Sheet membrane inner component; 31-Sheet; 32-Serrated protrusion; 33-Teardrop-shaped protrusion; 34-Horizontal groove; 35-Vertical groove; 36-Outer frame; 37-Fixing column; 38-Hemispherical protrusion; 39-Connecting column. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0041] like Figure 1 As shown, the absorption tower of the present invention includes a tower body 10, a liquid distributor 20 and a flat membrane internal component 30 arranged in a vertical position inside the tower body 10. The upper part of the tower body 10 is provided with an absorbent inlet 11 and a gas phase outlet 14, and the lower part is provided with a gas phase inlet 12 and an absorbent outlet 13.

[0042] The liquid distributor 20 is either a gravity distributor or a pressure distributor. The absorbent, after being evenly distributed by the liquid distributor 20, falls into the flat membrane inner part 30.

[0043] Combination Figure 2 a and Figure 2As shown in Figure b, the flat membrane internals 30 include a plurality of vertically arranged flat plates 31 and a support assembly for supporting and fixing the flat plates 31; a flow channel is formed between adjacent flat plates 31; the gas to be treated enters the flow channel from bottom to top and comes into countercurrent contact with the absorbent from the liquid distributor 20 to perform efficient gas-liquid mass transfer.

[0044] The above-mentioned absorption tower is suitable for industrial gas purification, such as the deep removal of acidic gases from industrial gases such as natural gas, fuel gas, and refinery dry gas.

[0045] Furthermore, the thickness of a single plate 31 is 1 / 120 to 1 / 60 of the inner diameter of the absorption tower, and the ratio of the thickness of a single plate 31 to the distance between two adjacent plates 31 (i.e., the plate spacing) is 1 / 4 to 1; the overall height of the plate membrane inner element 30 accounts for 1 / 4 to 1 / 2 of the height of the absorption tower.

[0046] Under different liquid flow rates, the absorbent can overflow onto the surface of the plate 31 at different speeds, and form a continuous, uniform liquid film with adjustable thickness according to different plate thicknesses and plate spacing.

[0047] Furthermore, the plate 31 is preferably made of a hydrophilic and corrosion-resistant material, which facilitates the formation of a liquid film on the surface of the absorbent, increases the gas-liquid contact area, and improves the gas-liquid mass transfer efficiency. The hydrophilic and corrosion-resistant material can be selected from stainless steel materials such as 304 stainless steel, 316L stainless steel, and duplex stainless steel, or materials such as polypropylene (PP), polyvinyl chloride (PVC), and alumina ceramics.

[0048] Taking the desulfurization tower as an example, when the hydrogen sulfide concentration in the gas to be treated is <3000ppm, the flat sheet membrane internals 30 can be made of polypropylene (PP) or polyvinyl chloride (PVC); when the hydrogen sulfide concentration in the gas to be treated is ≥3000ppm, the flat sheet membrane internals 30 can be made of stainless steel or alumina ceramic, which have better hydrophilicity.

[0049] Furthermore, the aforementioned flat sheet membrane internal component 30 is installed entirely inside the absorption tower. The overall outer diameter of the flat sheet membrane internal component 30 is slightly smaller than the inner diameter of the absorption tower, which facilitates subsequent maintenance, cleaning, and component replacement.

[0050] In some preferred embodiments, the gas-liquid mass transfer efficiency can be further improved by optimizing the structure of the flat sheet membrane internals 30; for example, the specific structure of the flat sheet membrane internals 30 can be referred to in Embodiments 1 to 3. It should be noted that, in the following embodiments, "continuous" refers to a continuous state in the horizontal and / or vertical directions, and "discontinuous" refers to a discontinuous state in both the horizontal and vertical directions.

[0051] Example 1

[0052] refer to Figures 3 to 6In this embodiment, the surface of the plate 31 in the flat membrane internal 30 is provided with continuous raised or grooved patterns, including serrated raised patterns 32, teardrop-shaped raised patterns 33, horizontal grooves 34, and vertical grooves 35. This type of structure can guide the absorbent to flow downward along a preset path to form a uniform and continuous liquid film. At the same time, some liquid can accumulate in the groove spaces between the patterns, effectively prolonging the total residence time of the liquid phase in the column and increasing the chances of reaction and absorption.

[0053] Taking the surface of the flat plate 31 with teardrop-shaped protrusions 33 as an example, such as Figure 7 As shown, when the absorbent is sprayed from the top of the tower onto the flat plate membrane internals 30, it spreads rapidly on the surface of the plate due to the hydrophilicity of the material. As the absorbent flows downward along the special teardrop-shaped texture, it forms a uniform and continuous liquid film at the very tip of the teardrop-shaped protrusions 33. At the same time, some of the absorbent will briefly stay and accumulate in the groove space between the two textures, thereby prolonging the overall residence time of the absorbent in the tower.

[0054] Meanwhile, the gas to be treated (e.g., natural gas containing H2S) enters from the bottom of the tower and flows upward along the flow channel formed between the plates 31, making full countercurrent contact with the downward flowing absorbent liquid film. As the upward flowing gas passes through the groove space, it generates stronger turbulent disturbances with the liquid accumulated there, thereby greatly improving the mass transfer efficiency and absorption efficiency.

[0055] The ratio of the horizontal width of the serrated protrusion 32 or the teardrop protrusion 33 to the thickness of the plate 31 is 1 / 4-1, and the ratio of its vertical height to the thickness of the plate 31 is 1 / 4-1.

[0056] The ratio of the depth of the horizontal groove 34 or the vertical groove 35 to the thickness of the plate 31 is 1 / 4 to 1 / 2; the ratio of the width of the horizontal groove 34 or the vertical groove 35 to the thickness of the plate 31 is 1 / 2 to 3 / 2; and the ratio of the spacing between adjacent grooves to the thickness of the plate 31 is 1 / 2 to 3 / 2.

[0057] In addition, such as Figure 2 a and Figure 2 As shown in Figure b, in this embodiment, the support component in the flat membrane inner component 30 is an outer frame 36. The outer frame 36 is provided with a slot (not shown in the figure) adapted to the size of the flat plate 31. The flat plate 31 is inserted into the slot of the outer frame 36 for fixation. The outer frame 36 can be a single-layer or multi-layer frame combination. When a multi-layer frame is used, adjacent frames are supported and fixed by fixing posts 37. The ratio of the overall height of the outer frame 36 to the height of a single flat plate 31 is 1 / 3-1.

[0058] Example 2

[0059] refer to Figures 8 to 9In this embodiment, the surface of the plate 31 in the flat film inner component 30 is provided with discontinuous raised texture, including staggered hemispherical protrusions 38 and aligned hemispherical protrusions 38.

[0060] When the gas and liquid phases flow counter-currently through the flow channel between the plates 31, the continuous liquid film and airflow are continuously segmented and disturbed by these discontinuous hemispherical protrusions 38, effectively disrupting the mass transfer boundary layer and achieving efficient gas-liquid mass transfer. This is because, on the one hand, the hemispherical protrusions 38 enhance interfacial turbulence; on the other hand, the high-speed airflow causes the liquid to splash upon impact with the hemispherical protrusions 38, forming a large number of tiny droplets. These splashed droplets significantly increase the total gas-liquid mass transfer area, thus achieving efficient absorption within a shorter contact path. Therefore, the texture design of this embodiment is more suitable for applications requiring further enhancement of gas-liquid interfacial disturbance or handling large gas volumes.

[0061] The ratio of the radius of the hemispherical protrusion 38 to the thickness of the plate 31 is 1 / 4-1; when staggered, the ratio of the distance between adjacent hemispherical protrusions 38 to the thickness of the plate 31 is 1 / 3-3 / 2; when aligned, the ratio of the distance between adjacent hemispherical protrusions 38 to the thickness of the plate 31 is 1 / 3-3 / 2.

[0062] In addition, such as Figure 2 a and Figure 2 As shown in Figure b, in this embodiment, the support component in the flat membrane inner component 30 is an outer frame 36. The outer frame 36 is provided with a slot (not shown in the figure) adapted to the size of the flat plate 31. The flat plate 31 is inserted into the slot of the outer frame 36 for fixation. The outer frame 36 can be a single-layer or multi-layer frame combination. When a multi-layer frame is used, adjacent frames are supported and fixed by fixing posts 37. The ratio of the overall height of the outer frame 36 to the height of a single flat plate 31 is 1 / 2-1.

[0063] Example 3

[0064] refer to Figure 10 a and Figure 10 In embodiment b, the support components in the flat membrane inner component 30 are a plurality of connecting columns 39. Adjacent flat plates 31 are supported and fixed by staggered connecting columns 39, simplifying the overall structure and eliminating the need for an external frame. Simultaneously, the connecting columns 39 can act as disturbance units, causing the flowing absorbent liquid to splash, thus increasing the probability of gas-liquid contact. The entire flat membrane inner component 30 can be integrally formed using 3D printing technology.

[0065] Furthermore, the ratio of the length of the connecting post 39 to the thickness of the plate 31 is 1.2-2; the ratio of the diameter of the connecting post 39 to the thickness of the plate 31 is 1 / 2-4; and the spacing between adjacent connecting posts 39 is 1-8 times the thickness of the plate 31.

[0066] Application examples

[0067] The following section presents performance tests on an absorption tower using the aforementioned flat-plate membrane internals, with a packed tower used as a comparison.

[0068] 1. Absorption Tower Parameter Settings

[0069] In this embodiment of the invention, the absorption tower has an inner diameter of 800 mm and a total effective height of 6 m; the flat membrane inner component 30 is made of stainless steel 316L, with an overall height of 1.5 m, and is composed of flat plates 31 with a thickness of 10 mm and a spacing of 20 mm.

[0070] The ratio of the horizontal width of the serrated protrusion 32 or the teardrop protrusion 33 to the thickness of the plate 31 is 1 / 2, and the ratio of its vertical height to the thickness of the plate 31 is 1.

[0071] The ratio of the depth of the horizontal groove 34 or the vertical groove 35 to the thickness of the plate 31 is 1 / 3; the ratio of the width of the horizontal groove 34 or the vertical groove 35 to the thickness of the plate 31 is 1; and the ratio of the spacing between adjacent grooves to the thickness of the plate 31 is 1.

[0072] The ratio of the radius of the hemispherical protrusion 38 to the thickness of the plate 31 is 1 / 2; when staggered, the ratio of the distance between adjacent hemispherical protrusions 38 to the thickness of the plate is 1; when aligned, the ratio of the distance between adjacent hemispherical protrusions 38 to the thickness of the plate 31 is 1.

[0073] The outer frame 36 is a three-layer frame combination, and the ratio of the overall height of the outer frame 36 to the height of a single plate 31 is 1.

[0074] The ratio of the length of the connecting post 39 to the thickness of the plate 31 is 1.5; the ratio of the diameter of the connecting post 39 to the thickness of the plate 31 is 1; and the ratio of the spacing between adjacent connecting posts 39 to the thickness of the plate 31 is 4.

[0075] The packed tower has an inner diameter of 800 mm and a total effective height of 6 m; the packing uses DN25 stainless steel Pall rings, and the packing layer stack height is 3 m.

[0076] 2. Specific process parameter settings

[0077] The specific parameters of the sulfur-containing gas to be treated are: gas flow rates of 1500 Nm³ / h and 3000 Nm³ / h, inlet gas H₂S concentration of 5000 ppm, and operating temperature of 35 ℃.

[0078] The specific parameters of the absorbent used are: 30wt% methyl diethanolamine (MDEA) aqueous solution.

[0079] 3. Performance Comparison

[0080] The desulfurization efficiency and pressure drop inside the absorption tower and packed tower using different types of flat-plate membrane internals are summarized in Table 1 below.

[0081] Table 1

[0082]

[0083] Analysis of Table 1 shows that the overall performance of the absorption tower using the flat-plate membrane internals of this invention is superior to that of traditional packed towers, especially when handling high-flow-rate gases. It achieves higher desulfurization efficiency while significantly reducing pressure drop (i.e., energy consumption) within the tower. By optimizing the surface geometry and arrangement of the flat plates, as well as the form of the support components, although the pressure drop increases to some extent compared to unpatterned flat plates, the desulfurization efficiency is significantly improved, and the improvement is more significant with higher gas flow rates (up to 3.6 percentage points). Among various pattern designs, continuous patterns are more suitable for low gas flow conditions, combining high desulfurization efficiency with low energy consumption; while for high gas flow conditions, discontinuous pattern designs have higher desulfurization efficiency.

[0084] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flat sheet membrane internals for an absorption column, characterized by, The flat plate membrane inner part comprises a plurality of vertically arranged flat plates and a support assembly for supporting and fixing the flat plates; flow channels are formed between adjacent flat plates; the support assembly is a plurality of connecting columns, and adjacent flat plates are supported and fixed by the interlaced connecting columns; the ratio of the length of the connecting column to the thickness of the flat plate is 1.2-2; the ratio of the diameter of the connecting column to the thickness of the flat plate is 1 / 2-4; and the spacing between adjacent connecting columns is 1-8 times the thickness of the flat plate.

2. The flat sheet membrane internals for absorption columns according to claim 1, characterized in that, The thickness of a single flat plate is 1 / 120-1 / 60 of the inner diameter of the absorption tower, and the ratio of the thickness of a single flat plate to the spacing between adjacent flat plates is 1 / 4-1; the overall height of the flat plate membrane inner part accounts for 1 / 4-1 / 2 of the height of the absorption tower.

3. The flat sheet membrane internals for absorption columns of claim 1, wherein, The flat plate is made of a hydrophilic corrosion-resistant material; the hydrophilic corrosion-resistant material is selected from one or more of stainless steel 304, stainless steel 316L, duplex stainless steel, polypropylene, polyvinyl chloride and alumina ceramic.

4. The flat sheet membrane internals for absorption columns of claim 1, wherein, The flat plate membrane inner part is integrally installed in the absorption tower, and the overall outer diameter of the flat plate membrane inner part is slightly smaller than the inner diameter of the absorption tower.

5. An absorption column employing the flat sheet membrane internals of any one of claims 1 to 4, characterised in that, The absorption tower comprises a tower body, a liquid distributor and a flat plate membrane inner part arranged in the tower body in sequence from top to bottom, an absorbent inlet and a gas phase outlet are arranged at the upper part of the tower body, and an absorbent outlet and a gas phase inlet are arranged at the lower part of the tower body. The liquid distributor is a gravity type distributor or a pressure type distributor.

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