Radial flow adsorption tower for optimizing variable mass flow distribution

Abstract

The invention belongs to the field of pressure swing adsorption oxygen production equipment, and particularly relates to a radial flow adsorption tower for optimizing variable mass flow distribution. The adsorption tower comprises a tower body (1) composed of an upper seal head (11), a cylinder (12) and a lower seal head (13), and an outer gas channel pipe (2-2) and an inner gas channel pipe (2-1) are arranged at the bottom of the tower body (1) and serve as channels for gas to enter and exit from the tower body; a supporting flat plate (3) is arranged at the bottom of the cylinder body (12), a flow guide sealing head (4) is welded below the supporting flat plate (3), the gap space is occupied, and the airflow direction in a lower sealing head (13) is changed; an outer-layer porous barrel (5) and an inner-layer porous barrel (6) are fixedly connected to the middle part of the inner cavity of the tower body (1), and the bottom of the outer-layer porous barrel (5) and the bottom of the inner-layer porous barrel (6) are welded with the upper part of the supporting flat plate (3). According to the invention, the radial pressure and flow velocity distribution of the adsorbent bed layer between the outer-layer porous cylinder and the inner-layer porous cylinder in the height direction is optimized, the internal gap space is reduced, and the adsorbent efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the field of oxygen production equipment using pressure swing adsorption technology, and in particular is a radial flow adsorption tower for optimizing variable mass flow distribution. Background Art

[0002] Pressure swing adsorption technology uses the principle of pressurized adsorption and desorption of adsorbents to separate nitrogen from the air and obtain the required enriched oxygen. Compared with traditional axial flow adsorbers, radial flow adsorption towers have lower bed pressure drop, smaller footprint and operating energy consumption, and are more suitable for large-scale pressure swing adsorption oxygen production systems. In the pressure swing adsorption oxygen production process, the gas flow direction within the cross-section of the adsorbent bed of the radial flow adsorption tower is bidirectional, i.e. centripetal adsorption and centrifugal desorption and cleaning. In the adsorption stage, the gas passing through the bed is reduced due to the adsorption of nitrogen. In the desorption and cleaning stage, the gas passing through the bed is increased due to the desorption of nitrogen. This is a case of bidirectional variable mass flow.

[0003] The existing research and design of radial flow adsorption tower distribution structure focuses on the airflow distribution at the height of the adsorbent bed during the adsorption stage, but does not conduct a detailed study of the adsorption tower in combination with each stage of the process steps to obtain a distribution structure suitable for the overall airflow distribution. The "π-type flow channel" can improve the pressure gradient difference in the airflow direction at the bed height to a certain extent, so it is widely used in radial flow adsorption towers. However, for large radial flow adsorption towers with a bed height of more than 5m, the pressure gradient difference in the airflow direction at the bed height is greater, and a more uneven radial component velocity is distributed in the bed.

[0004] The patent with the authorization announcement number CN203678219U provides a "Z-type flow channel" design, which improves the bias flow in the height direction of the adsorbent bed by setting conical inner and outer distributors in the inner and outer flow channels. This design simply explains the principle of improving bias flow by the corresponding matching relationship between gas volume and spatial volume, and does not consider the influence of many other factors. In addition, it does not involve the variable quality of adsorption and desorption cleaning of gas in the adsorption tower. Summary of the invention

[0005] The purpose of the present invention is to provide a radial flow adsorption tower with optimized variable mass flow distribution, so as to solve the problem of low adsorbent utilization rate caused by uneven flow distribution of adsorbent bed height in the radial flow adsorption tower with a height of more than 5m during the centripetal adsorption and centrifugal desorption cleaning variable mass process in the prior art.

[0006] In order to achieve the purpose of the present invention, the specific technical scheme of the present invention is as follows:

[0007] A radial flow adsorption tower for optimizing variable mass flow distribution comprises a tower body consisting of an upper head, a cylinder and a lower head. An outer airway pipe and an inner airway pipe are arranged at the bottom of the tower body as channels for gas to enter and exit the tower body; the bottom of the cylinder is a supporting plate, and a guide head is welded below the supporting plate to occupy the gap space and change the direction of the airflow in the lower head; an outer porous cylinder and an inner porous cylinder are fixedly connected in the middle of the inner cavity of the tower body, and the bottoms thereof are welded to the top of the supporting plate; the top of the outer porous cylinder is welded to the tower body through a sealing plate, forming an outer airway with a top closed and transformed from axial to radial with the tower body; a closing plate is welded to the top of the inner porous cylinder; a guide cone is arranged in the middle of the cylinder, and the large end of the guide cone is fixedly connected to the bottom of the closing plate and is upside down suspended at the center of the inner porous cylinder, forming an inner airway with a top closed and transformed from radial to axial; a ring-shaped airbag is arranged in the upper head, and after being inflated, the ring-shaped airbag is filled in the upper head and abuts against the top of the adsorbent between the outer porous cylinder and the inner porous cylinder to close the top and compact the adsorbent.

[0008] Furthermore, in the radial flow adsorption tower for optimizing variable mass flow distribution, the cylinder is a cylindrical rotating shell, and the lower head and the upper head are respectively welded at both ends of the cylinder; there is a conical head in the middle of the lower head, the outer airway pipe is connected to the smaller end of the conical head, and the inner airway pipe passes through the side of the conical head.

[0009] Furthermore, in the radial flow adsorption tower for optimizing variable mass flow distribution, the guide head and the lower head have similar shapes to make the flow channel continuous; the concave side space is closed to reduce the void space of the external air channel.

[0010] Furthermore, in the radial flow adsorption tower for optimizing variable mass flow distribution, the central axes of the outer porous cylinder and the inner porous cylinder coincide with the central axis of the cylinder, so that the inner air channel and the outer air channel are both concentric annular channels.

[0011] Furthermore, in the radial flow adsorption tower for optimizing the variable mass flow distribution, the opening areas on the outer porous cylinder and the inner porous cylinder are arranged in sections along the bed height direction, and gradually increase in equal proportion within the range of 13%-45%, so as to evenly distribute the gas through the bed during the adsorption stage, thereby improving the effect of the centripetal radial variable mass flow.

[0012] Furthermore, in the radial flow adsorption tower with optimized variable mass flow distribution, the opening area of ​​the inner porous cylinder in the 150mm-500mm height region near the bottom is 30%-80% of the opening area of ​​the outer porous cylinder at the same height, so as to limit the speed of gas passing through this section of the bed during the desorption and cleaning stage, thereby improving the effect of centrifugal radial desorption and cleaning.

[0013] Furthermore, in the radial flow adsorption tower with optimized variable mass flow distribution, the length of the guide cone is 50%-80% of the length of the inner porous cylinder, so that there is airflow buffer space in the lower area of ​​the inner airway.

[0014] Furthermore, in the radial flow adsorption tower with optimized variable mass flow distribution, the ring-shaped airbag is inflated with air, and the internal pressure thereof is higher than the maximum working pressure of the tower body.

[0015] Furthermore, in the radial flow adsorption tower with optimized variable mass flow distribution, the lower part of the ring-shaped airbag covers and abuts against the top of the adsorbent bed between the outer porous cylinder and the inner porous cylinder, and transmits continuous elastic positive pressure through appropriate contact parts to seal the top and compact the adsorbent.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention arranges the opening areas of the outer porous cylinder and the inner porous cylinder in sections along the bed height direction in a traditional "π-type flow channel" adsorption tower, and gradually increases them in equal proportion, thereby improving the uniformity of flow distribution at the adsorbent bed height of a radial flow adsorption tower with a height exceeding 5m; at the same time, the opening area of ​​a certain height area at the bottom of the inner porous cylinder is adjusted, thereby improving the problem of low adsorbent utilization rate caused by uneven flow distribution in this area during the centrifugal desorption and cleaning process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a radial flow adsorption tower for optimizing variable mass flow distribution according to the present invention;

[0019] Among them, 1 is the tower body, 2-1 is the inner airway pipe, 2-2 is the outer airway pipe, 3 is the supporting plate, 4 is the flow guide head, 5 is the outer porous cylinder, 6 is the inner porous cylinder, 7-1 is the closing plate, 7-2 is the closing plate, 8 is the flow guide cone, 9 is the ring-shaped air bag, 10 is the conical head, 11 is the upper head, 12 is the cylinder, and 13 is the lower head.

[0020] Figure 2 A cross-sectional view of a radial flow adsorption tower with optimized variable mass flow distribution according to the present invention;

[0021] In the figure: the solid arrows are the airflow direction during the adsorption process, and the hollow arrows are the airflow direction during the cleaning process.

[0022] Figure 3 It is a schematic diagram of the segmented arrangement of the opening areas of the outer porous cylinder and the inner porous cylinder in the bed height direction of the present invention;

[0023] Figure 4It is the radial pressure difference curve of the adsorbent bed along the height direction when the adsorption and cleaning of the process cycle of the present invention are respectively completed. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that, in order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0029] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the present invention should be pointed out that, in the present invention, unless the specific structure, connection relationship, positional relationship, power source relationship, etc. are specifically written out, the structure, connection relationship, positional relationship, power source relationship, etc. involved in the present invention are all known by those skilled in the art on the basis of the prior art without creative work.

[0032] Embodiment 1:

[0033] A radial flow adsorption tower with optimized variable mass flow distribution, the schematic diagram of which is shown in Figure 1 The adsorption tower includes a tower body, an outer airway tube, a flow guide head, an outer porous cylinder, an inner porous cylinder, a flow guide cone, an inner airway tube and a ring-shaped airbag. The outer airway tube and the inner airway tube are arranged at the bottom of the tower body, and the flow guide head is welded under the support plate; the outer porous cylinder and the inner porous cylinder are both fixedly connected to the middle of the inner cavity of the tower body, and the bottom is welded to the top of the support plate; the top of the outer porous cylinder is welded to the tower body through a sealing plate, and a closing plate is welded to the top of the inner porous cylinder. The large end of the flow guide cone is fixedly connected to the bottom of the closing plate and is invertedly suspended in the center of the inner porous cylinder; after the ring-shaped airbag is inflated, it is filled in the upper head and abuts against the top of the adsorbent between the outer porous cylinder and the inner porous cylinder to seal the top and compact the adsorbent.

[0034] Combination Figure 1 and Figure 2 The tower body includes a cylinder, a lower head, and an upper head, forming a closed container. The cylinder is a cylindrical rotary shell, and the lower head and the upper head are welded to the upper and lower ends of the cylinder respectively. There is a conical head in the middle of the lower head, and the outer airway pipe is connected to the small end of the conical head as the inlet and outlet channel of air or desorbed nitrogen. The inner airway pipe turns from the center of the tower body and passes through the side of the conical head as the inlet and outlet channel of enriched oxygen.

[0035] Combination Figure 2The inner side of the guide head is closed, occupying the gap space between the support plate and the lower head. The guide head has a similar shape to the lower head to make the flow channel continuous and reduce the gap space between the inner and outer gas channels of the tower body.

[0036] Combination Figure 2 The central axis of the outer porous cylinder and the inner porous cylinder coincides with the central axis of the tower cylinder so that the outer airway and the inner airway are both concentric annular channels, the outer airway communicates with the outer airway pipe, and the inner airway communicates with the inner airway pipe. The outer porous cylinder and the inner porous cylinder have holes in their walls and are both covered with wire mesh.

[0037] Combination Figure 3 , Figure 4 , the opening areas of the outer porous cylinder and the inner porous cylinder are arranged in sections along the bed height direction, and gradually increase in proportion, and a value is selected within the range of 13%-45%. More preferably, the section arrangement in the bed height direction is divided into at least 3 sections, with the opening area of ​​the lower section being about 13%-22%, the opening area of ​​the middle section being about 22%-33%, and the opening area of ​​the upper section being about 33%-45%. Since the airflow path near the bottom of the bed is shorter, the radial pressure difference of the adsorbent bed in this area is greater, and the airflow will flow preferentially, causing bias flow. Although the "π-type flow channel" can suppress this trend, as the bed height of a large adsorption tower exceeds 5m, this suppression ability will become limited. By arranging the opening areas of the outer porous cylinder and the inner porous cylinder in sections along the bed height direction, the gas in the inner and outer gas channels is diverted more to the upper part, so as to evenly distribute the gas through the bed during the adsorption stage, so as to achieve the effect of optimizing the variable mass flow distribution.

[0038] Combination Figure 3 , Figure 4 The opening area of ​​the inner porous cylinder near the bottom of the 150mm-500mm height area is 30%-80% of the opening area of ​​the outer porous cylinder at the same height. According to the numerical simulation calculation of variable mass flow, the centrifugal radial velocity of the airflow near the bottom of the bed during the cleaning process is greater than that of the upper bed, and the rapid passage makes the cleaning effect of this area poor. This section of opening setting can reduce the centrifugal radial velocity of the gas passing through this section of the bed, thereby improving the effect of radial desorption cleaning of centrifugal cleaning.

[0039] Combination Figure 2 The change in the shape of the guide cone along the height direction causes the cross-sectional area of ​​the inner airway to change along the height direction, effectively matching the change in the airflow in the height direction. The length of the guide cone is 50%-80% of the length of the inner porous cylinder, so that there is airflow buffer space in the lower area of ​​the inner airway, and the airflow can be gathered and distributed more smoothly in the inner airway.

[0040] Combination Figure 2After the ring-shaped airbag is inflated, it fills up the upper head space above the adsorbent bed. The internal pressure is higher than the maximum working pressure in the tower body. The lower part covers and abuts against the top of the adsorbent bed between the outer porous cylinder and the inner porous cylinder. Continuous elastic positive pressure is transmitted through appropriate contact parts to seal the top and compact the adsorbent at any time to prevent the adsorbent from pulverizing and losing after long-term use, resulting in bed gaps.

[0041] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0042] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A radial flow adsorption tower for optimizing variable mass flow distribution, comprising a tower body (1) consisting of an upper head (11), a cylinder (12) and a lower head (13), characterized in that: An outer airway pipe (2-2) and an inner airway pipe (2-1) are arranged at the bottom of the tower body (1) to serve as passages for gas to enter and exit the tower body; The bottom of the cylinder (12) is a support plate (3), and a flow guide head (4) is welded below the support plate (3), occupying the gap space and changing the airflow direction in the lower head (13); an outer porous cylinder (5) and an inner porous cylinder (6) are fixedly connected in the middle of the inner cavity of the tower body (1), and the bottom of the outer porous cylinder (5) is welded to the top of the support plate (3); the top of the outer porous cylinder (5) is welded to the tower body (1) through a sealing plate (7-2), and forms an external air passage with a top closed and transformed from axial to radial direction with the tower body (1). A closing plate (7-1) is welded to the top of the inner porous cylinder (6); a guide cone (8) is arranged in the middle of the cylinder (12); the large end of the guide cone (8) is fixedly connected to the bottom of the closing plate (7-1) and is suspended upside down at the center of the inner porous cylinder (6), forming an inner air passage with a closed top that changes from radial to axial direction; a ring-shaped airbag (9) is arranged in the upper head (11); after being inflated, the ring-shaped airbag (9) fills the upper head (11) and abuts between the outer porous cylinder (5) and the inner porous cylinder (6).

2. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 1, characterized in that: The cylinder (12) is a cylindrical rotating shell, and the lower head (13) and the upper head (12) are respectively welded to the two ends of the cylinder (12); a conical head (10) is provided in the middle of the lower head (13), the outer airway pipe (2-1) is connected to the small end of the conical head, and the inner airway pipe (2-2) passes through the side of the conical head.

3. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 1 or 2, characterized in that: The flow guide head (4) and the lower head (13) have similar shapes to make the flow channel continuous; the concave side space is closed to reduce the void space of the external air channel.

4. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 3, characterized in that: The central axes of the outer porous cylinder (5) and the inner porous cylinder (6) coincide with the central axis of the cylinder (12), so that the inner air passage and the outer air passage are both concentric annular channels.

5. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 1 or 4, characterized in that: The opening areas on the outer porous cylinder (5) and the inner porous cylinder (6) are arranged in sections along the bed height direction and gradually increase in equal proportion within a range of 13% to 45%.

6. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 5, characterized in that: The opening area of ​​the 150 mm to 500 mm region near the bottom of the inner porous cylinder (6) is 30% to 80% of the opening area of ​​the outer porous cylinder (5) at the same height, so as to improve the effect of centrifugal radial flow.

7. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 1, 2, 4 or 6, characterized in that: The length of the guide cone (8) is 50%-80% of the length of the inner porous cylinder (6), so that there is space for airflow buffering in the lower area of ​​the inner airway.

8. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 7, characterized in that: The ring-shaped air bag (9) is inflated with air, and the internal pressure thereof is higher than the maximum working pressure of the tower body (1).

9. A radial flow adsorption tower with optimized variable mass flow distribution according to claim 1 or 8, characterized in that: The lower part of the ring-shaped air bag (9) covers and abuts against the top of the adsorbent bed layer between the outer porous cylinder (5) and the inner porous cylinder (6) to seal the top and compact the adsorbent.

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