An oxygen production adsorption tower with a composite adsorption bed

Abstract

The present invention relates to an oxygen production adsorption tower with a composite adsorption bed. The composite adsorption bed comprises, from top to bottom, an exhaust port, a composite adsorption bed, a support plate and an air inlet. The outer side of the composite adsorption bed is an air inlet channel, the inner side is an air outlet channel, the top of the air outlet channel is connected to the exhaust port, and the bottom of the air inlet channel is connected to the air inlet. The composite adsorption bed is filled with adsorption material, and the adsorption material comprises Li-LSX molecular sieve and Ca-LSX molecular sieve. A portion of the composite adsorption bed close to the air inlet channel is completely filled with Li-LSX molecular sieve, and a portion close to the air outlet channel is completely filled with Ca-LSX molecular sieve. The volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the remaining portion of the composite adsorption bed is 1:(1-5.7).

Description

Technical Field

[0001] The invention belongs to the technical field of pressure swing adsorption oxygen production, and in particular relates to an oxygen production adsorption tower with a composite adsorption bed. Background Art

[0002] The industrial application of pressure swing adsorption (PSA) oxygen production technology originated in the 1970s. The oxygen purity of its product gas ranges from 50% to 93%, meeting the oxygen needs of industries such as steel, metallurgy, chemicals, furnaces, glass, and papermaking. The adsorbent is the foundation of PSA oxygen production, and its performance determines the adsorption and separation efficiency and the economic viability of equipment investment. Initially, zeolite molecular sieves, such as 5A and 13X molecular sieves, were commonly used, but these materials exhibited limited nitrogen adsorption capacity and low nitrogen-oxygen separation coefficients.

[0003] Currently, lithium molecular sieves, such as Li-LSX, Li-Ag-LSX, and Li-Ca-LSX, are primarily used, offering excellent adsorption performance. However, the high cost of lithium salts also leads to higher costs for lithium molecular sieves. Another adsorbent, Ca-LSX, exhibits a higher static nitrogen adsorption capacity than Li-LSX. Improving adsorption tower performance depends on increasing the dynamic nitrogen adsorption capacity (the difference between the static adsorption capacity during adsorption and the static adsorption capacity during desorption) of the adsorbent. The nitrogen adsorption capacity of Ca-LSX is higher during adsorption and desorption, so its dynamic adsorption capacity may not be greater than that of Li-LSX. Furthermore, the oxygen adsorption capacity of Ca-LSX is also higher than that of Li-LSX. Consequently, when using Ca-LSX, oxygen loss is higher even with the same air intake. How to scientifically and rationally use Li-LSX and Ca-LSX adsorbents to efficiently and cost-effectively improve the adsorption oxygen production effect of the adsorption tower is a problem faced by those skilled in the art. Summary of the Invention

[0004] To address the above problems, the present invention provides an oxygen production adsorption tower with a composite adsorption bed, which comprises, from top to bottom, an exhaust port, a composite adsorption bed, a support plate, and an air inlet. The outer side of the composite adsorption bed is an air inlet channel, and the inner side is an air outlet channel. The top of the air outlet channel is connected to the exhaust port, and the bottom of the air inlet channel is connected to the air inlet.

[0005] The composite adsorption bed is filled with adsorption materials, which include Li-LSX molecular sieve and Ca-LSX molecular sieve. The part of the composite adsorption bed close to the air inlet channel is completely filled with Li-LSX molecular sieve, and the part close to the air outlet channel is completely filled with Ca-LSX molecular sieve. The volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the remaining part of the composite adsorption bed is 1:(1-5.7).

[0006] The adsorption bed of the adsorption tower of the present invention utilizes Li-LSX and Ca-LSX molecular sieves to form a composite adsorption bed, leveraging the advantages of each to improve oxygen yield. The Ca-LSX molecular sieve on the inner side of the adsorption bed has a higher dynamic adsorption capacity for nitrogen than the Li-LSX molecular sieve, allowing the adsorption bed to process more air and produce more product oxygen, thereby improving yield and reducing the power consumption of standard pure oxygen. The Ca-LSX molecular sieve is relatively low in cost, which can reduce the overall cost of oxygen production.

[0007] Optionally, the composite adsorption bed includes a calcium type region, a mixed region and a lithium type region from the inside to the outside, the calcium type region is filled entirely with Ca-LSX type molecular sieves, the lithium type region is filled entirely with Li-LSX type molecular sieves, and the mixed region is filled with Li-LSX type molecular sieves and Ca-LSX type molecular sieves;

[0008] The volume ratio of the calcium type region, the mixed region and the lithium type region is 1:(5-8):(0.7-1.2).

[0009] Optionally, the volume ratio of the Ca-LSX molecular sieve to the Li-LSX molecular sieve in the mixing zone is 1:(1.5-4).

[0010] Optionally, the composite adsorption bed is provided with a plurality of adsorption discs from top to bottom, the adsorption discs are annular, and the adsorption discs include a plurality of adsorption rings from the outside to the inside, and all the adsorption rings are concentrically arranged;

[0011] The adsorption ring is composed of several adsorption blocks spliced ​​horizontally left and right. The adsorption blocks are fan-shaped and hollow inside for filling adsorption materials.

[0012] Optionally, a positioning cylinder is provided between the composite adsorption bed and the gas outlet channel, for defining the position of the adsorption block of the innermost shell ring of the adsorption disk; the positioning cylinder is a frame structure;

[0013] A rotating motor is provided above the adsorption tower. The rotating shaft connected to the rotating motor penetrates into the adsorption tower and is connected to the inner side of the top of the positioning cylinder through several connecting rods, which can drive the positioning cylinder to rotate.

[0014] Further optionally, a plurality of connecting cables are connected to the corresponding positioning cylinder above each adsorption plate, and the number of connecting cables corresponding to one adsorption plate is the same as the number of its adsorption blocks, and the connecting cables pass above the center line of the corresponding adsorption block, that is, the center line of the adsorption block corresponding to the connecting cable;

[0015] A connecting ring is provided at the center of the upper surface of the adsorption block, so that the corresponding connecting rope passes through the connecting ring. A driving device is provided on the connecting ring for driving the adsorption block to slide along the corresponding connecting rope.

[0016] Optionally, a movable frame is provided in the air inlet channel, the movable frame is cylindrical and is arranged close to the inner wall of the adsorption tower and has a certain distance from the inner wall; the movable frame includes a plurality of vertical rods and a plurality of rotating rings, and the vertical rods are evenly arranged along the circumference of the inner wall of the adsorption tower to provide support for the rotating rings;

[0017] The rotating ring is arranged on the vertical rod from top to bottom, and the rotating ring corresponds to the adsorption plate one by one; the rotating ring includes an outer shell ring and an inner shell ring. The outer side of the outer shell ring is fixedly connected to a plurality of vertical rods, and the inner side is provided with a guide rail. The inner shell ring is slidably connected to the guide rail so that the inner shell ring can rotate horizontally along the guide rail.

[0018] The end points of the plurality of connecting cables are connected to corresponding positions on the inner side surface of the inner shell ring, so that the adsorption blocks of the same adsorption disk are arranged in sequence along the corresponding inner shell ring without overlapping.

[0019] Optionally, the top of the movable rack is connected to a lifting device, which is provided on the inner wall of the adsorption tower and is used to control the vertical height of the movable rack.

[0020] Since the adsorption disk is composed of several adsorption circles, the outer circle of the same adsorption disk belongs to the lithium type area, the inner circle belongs to the calcium type area, and the adsorption circle in the middle belongs to the mixed area.

[0021] Further optionally, the volume ratio of Ca-LSX and Li-LSX type molecular sieves in the adsorption circle on the innermost side of the mixing zone (i.e., closest to the calcium type zone) is 1:1.5, and the volume ratio of Ca-LSX and Li-LSX type molecular sieves in the adsorption circle on the outermost side (i.e., closest to the lithium type zone) is 1:4. The volume ratio of Ca-LSX and Li-LSX type molecular sieves in the adsorption circle between the outermost and innermost sides gradually decreases linearly from the inside to the outside.

[0022] The volume ratio of the Ca-LSX to the Li-LSX molecular sieves in each adsorption block of the same adsorption circle is equal to the volume ratio of the Ca-LSX to the Li-LSX molecular sieves in the entire adsorption circle.

[0023] Further preferably, a dehydration zone is set between the lithium type zone and the air inlet channel, the volume ratio of the lithium type zone to the dehydration zone is 1: (0.05-0.1), and the adsorption circle corresponding to the dehydration zone is fully filled with 13X type oxygen-making molecular sieve for dehydrating the raw gas input into the air inlet channel.

[0024] The Li-LSX molecular sieve, Ca-LSX molecular sieve and 13X oxygen-generating molecular sieve used in the present invention are all conventional products on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the oxygen production adsorption tower with a composite adsorption bed of Example 1;

[0026] Figure 2 Schematic diagram of the structure of the oxygen production adsorption tower with a composite adsorption bed of Example 7;

[0027] Figure 3 for Figure 2 A partial top view of

[0028] Figure 4 for Figure 2 Partial three-dimensional schematic diagram.

[0029] In the accompanying drawings, 1-exhaust port, 2-composite adsorption bed, 3-support plate, 4-air inlet, 5-air inlet channel, 6-air outlet channel, 7-calcium type zone, 8-mixing zone, 9-lithium type zone, 10-adsorption disk, 11-adsorption block, 12-movable frame, 13-connecting rope, 14-positioning cylinder, 15-rotating motor, 16-connecting rod, 17-adsorption ring, 18-connecting ring, 19-vertical rod, 20-rotating ring, 21-outer shell ring, 22-inner shell ring. DETAILED DESCRIPTION

[0030] Example 1

[0031] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, such as Figure 1 As shown, from top to bottom, it includes an exhaust port 1, a composite adsorption bed 2, a support plate 3 and an air inlet 4. The outer side of the composite adsorption bed 2 is an air inlet channel 5, and the inner side is an air outlet channel 6. The top of the air outlet channel 6 is connected to the exhaust port 15, and the bottom of the air inlet channel is connected to the air inlet 4.

[0032] The composite adsorption bed 2 is filled with adsorption materials, including Li-LSX molecular sieve and Ca-LSX molecular sieve. The part of the composite adsorption bed close to the air inlet channel is filled with Li-LSX molecular sieve, and the part close to the air outlet channel is filled with Ca-LSX molecular sieve. The volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the remaining part of the composite adsorption bed is 1:1.

[0033] The composite adsorption bed includes a calcium type region 7, a mixed region 8 and a lithium type region 9 from the inside to the outside. The calcium type region 7 is filled entirely with Ca-LSX type molecular sieves, the lithium type region 9 is filled entirely with Li-LSX type molecular sieves, and the mixed region 8 is filled with Li-LSX type molecular sieves and Ca-LSX type molecular sieves.

[0034] The volume ratio of the calcium type region, the mixed region and the lithium type region is 1:5:0.7.

[0035] The calcium type area, the mixed area and the lithium type area are all provided with a mesh cage-type support to provide support and space for loading the adsorbent. The support plate is used to support the composite adsorption bed.

[0036] Example 2

[0037] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as that of Example 1, except that the volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the mixing zone of the composite adsorption bed is 1:5.7.

[0038] Example 3

[0039] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as that of Example 1, except that the volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the mixing zone of the composite adsorption bed is 1:1.5.

[0040] Example 4

[0041] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as that of Example 1, except that the volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the mixing zone of the composite adsorption bed is 1:4.

[0042] Comparative Example 1

[0043] This comparative example provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as Example 1, except that the volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the mixing zone of the composite adsorption bed is 1:0.9.

[0044] Comparative Example 2

[0045] This comparative example provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as Example 1, except that only Li-LSX molecular sieve is contained in the adsorption bed, and no Ca-LSX molecular sieve is loaded.

[0046] Example 5

[0047] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as that of Example 3, except that the volume ratio of the calcium type zone, the mixed zone and the lithium type zone is 1:8:1.2.

[0048] Example 6

[0049] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as that of Example 3, except that the volume ratio of the calcium type zone, the mixed zone and the lithium type zone is 1:8:0.6.

[0050] Example 7

[0051] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as that of embodiment 3, except that Figure 2-Figure 4As shown, the composite adsorption bed is provided with a plurality of adsorption discs 10 from top to bottom. The adsorption disc 10 is annular and includes a plurality of adsorption rings 17 from the outside to the inside. All the adsorption rings 17 are concentrically arranged and surround the adsorption disc 10 in layers. The diameter of the adsorption ring 17 gradually decreases from the outside to the inside.

[0052] The adsorption ring 17 is composed of several adsorption blocks 11 spliced ​​horizontally from left to right. The adsorption block 11 is fan-shaped and hollow inside for filling adsorption material. The adsorption block 11 is a mesh cage with mesh holes evenly distributed on the surface to facilitate the entry of raw gas into the adsorption block 11.

[0053] The adsorption blocks of the two adjacent adsorption rings 17 are staggered in the horizontal direction to prevent the center lines of the two adsorption blocks corresponding to the inner shell ring 22 and the outer shell ring 21 from being on the same radial line.

[0054] A positioning cylinder 14 is provided between the composite adsorption bed 2 and the gas outlet channel 6 for defining the position of the adsorption block 11 in the innermost circle of the adsorption disk 10; the positioning cylinder 14 is a frame structure;

[0055] A rotating motor 15 is provided above the adsorption tower. The rotating shaft connected to the rotating motor 15 penetrates into the adsorption tower and is connected to the inner side of the top of the positioning cylinder 14 through a plurality of connecting rods 16, which can drive the positioning cylinder 14 to rotate.

[0056] As a specific embodiment, the adsorption tower is cylindrical, the composite adsorption bed 2 and the air inlet channel 5 are both annular and sequentially surround the outside of the air outlet channel 6, and the positioning cylinder 14 is cylindrical.

[0057] The support plate 3 is circular and is located above the air inlet 4. The diameter of the support plate 3 is not less than the outer diameter of the adsorption disk 10. It is used to block the raw gas input from the air inlet 4, so that the raw gas flows radially along the bottom of the adsorption tower to the bottom of the air inlet channel 5, and then flows upward along the air inlet channel 5 to the composite adsorption bed 2.

[0058] The inner side of the innermost adsorption ring 17 of the adsorption disk 10 is in close contact with the outer side of the positioning cylinder 14 to prevent the adsorption disk 10 from entering the air outlet channel 6;

[0059] A plurality of connecting cables 13 are connected to the corresponding positioning cylinder 14 above each adsorption plate 10. The number of connecting cables 13 corresponding to one adsorption plate 10 is the same as the number of its adsorption blocks 11. The connecting cables 13 pass above the center line of the corresponding adsorption block 11, that is, the connecting cables 13 correspond to the center line of the corresponding adsorption block 11.

[0060] A connecting ring 18 is provided at the center of the upper surface of the adsorption block 11 , so that the corresponding connecting rope 13 passes through the connecting ring 18 . A driving device is provided on the connecting ring 18 for driving the adsorption block 11 to slide along the corresponding connecting rope 13 .

[0061] A movable frame 12 is provided in the air inlet passage 5. The movable frame 12 is cylindrical and is arranged close to the inner wall of the adsorption tower at a certain distance from the inner wall. The movable frame 12 includes a plurality of vertical rods 19 and a plurality of rotating rings 20. The vertical rods 19 are evenly arranged along the circumference of the inner wall of the adsorption tower to provide support for the rotating rings 20.

[0062] The rotating ring 20 is arranged on the vertical rod 19 from top to bottom, and the rotating ring 20 corresponds to the suction plate 10 one by one. The rotating ring 20 includes an outer ring 21 and an inner ring 22. The outer side of the outer ring 21 is fixedly connected to a plurality of vertical rods 19, and the inner side is provided with a guide rail. The inner ring 22 is slidably connected to the guide rail so that the inner ring 22 can rotate horizontally along the guide rail.

[0063] The end points of the plurality of connecting cables 13 are connected to corresponding positions on the inner side surface of the inner shell ring 22 , so that the adsorption blocks 11 of the same adsorption disk 10 are arranged in sequence along the corresponding inner shell ring 22 without overlapping.

[0064] The end points of the connecting ropes 13 corresponding to the same adsorption disc 10 are connected to different positions at the same horizontal height of the mobile rack 12 (i.e., the same inner shell ring 22), so that the adsorption blocks 11 of the same adsorption disc 10 can be arranged in a circle at the same height along the circumference of the adsorption tower on the mobile rack 12.

[0065] The connecting rope 13 is a steel rope with spiral patterns on the outer surface and has a certain flexibility. The driving device is fixedly connected to the corresponding connecting ring 18. A through hole is provided in the driving device. The internal thread of the inner wall of the through hole is adapted to the external thread of the steel rope. A gear can be connected to the outside of the through hole. As long as the driving gear rotates forward or reverse, the driving device can be driven to move back and forth along the steel rope.

[0066] Since the air inlet channel 5, the composite adsorption bed 2, and the air outlet channel 6 are arranged from the outside to the inside of the adsorption tower, and the inner diameter of the composite adsorption bed 2 is smaller than the air inlet channel 5, the adsorption blocks 11 of a circle of adsorption rings 17 are dispersed after sliding onto the movable frame 12, and will not fill a circle. The adsorption blocks 11 of the same adsorption disk 10 can be slid to different positions at the same height of the movable frame 12 via the connecting ropes 13 to form a circle. Since the adsorption blocks 11 of the two adjacent adsorption rings 17 are staggered in the horizontal direction, the center lines of the adsorption blocks 11 with similar positions in the inner and outer shell rings 21 of the same adsorption disk 10 can be avoided to the greatest extent possible. However, it is also possible that the center lines of the adsorption blocks 11 of two adsorption rings 17 separated by one or two circles are on the same straight line. In this case, if not adjusted, the starting points of the connecting ropes 13 corresponding to the adsorption blocks 11 of the inner shell ring 22 and the connecting ropes 13 corresponding to the adsorption blocks 11 of the outer shell ring 21 on the positioning ring will overlap, which may affect the smooth sliding of the two circles of adsorption blocks 11. In this case, the present invention sets the starting points of the connecting cables 13 corresponding to the adsorption blocks 11 of the outer shell 21 and the inner shell 22 slightly staggered, while the end points of the connecting cables 13 are still at different positions at the same height on the movable frame 12. Since the adsorption blocks 11 of the outer shell 21 are saturated with adsorption first, and the adsorption blocks 11 of the inner shell 22 are saturated with adsorption later, the adsorption blocks 11 of the outer shell 21 slide onto the movable frame 12 via the connecting cables 13 first, and the adsorption blocks 11 of the inner shell 22 move later. The spacing between the two adjacent adsorption discs 10 above and below is very small, only accommodating the connecting cables 13 corresponding to the lower adsorption disc 10. Therefore, the packing density of the composite adsorption bed 2 is still very high.

[0067] The end point of each connecting cable 13 is provided with a limiting component at the connection point on the inner shell ring 22. When the corresponding adsorption block 11 slides to the inner shell ring 22, the connecting ring 18 touches the limiting component, and the limiting component clamps the connecting ring 18, thereby positioning it. Since there is a gap between the mobile frame 12 and the inner wall of the adsorption tower, the connecting ring 18 is located in the middle of the adsorption block 11, and part of the adsorption block 11 is located in the space between the mobile frame 12 and the inner wall, keeping the adsorption block 11 stable.

[0068] The limiting component can be an openable and closable lock. When the connecting ring 18 touches the lock, the lock is sensed and closed to lock the connecting ring 18.

[0069] The top of the movable frame 12 is connected to a lifting device, which is provided on the inner wall of the adsorption tower and is used to control the vertical height of the movable frame 12 .

[0070] The bottom of the vertical rod 19 of the mobile frame 12 can be inserted into the bottom plate of the adsorption tower, and three-layer clamping positions are provided in the insertion hole, namely upper, middle and lower layers, so that the mobile frame 12 can be supported after moving up and down; the lifting device also provides support for the mobile frame 12, and the lifting device can be a conventional device with a lifting function, such as a hydraulic device, a lever lifting device, a lifting device composed of a gear and a motor, etc.

[0071] During adsorption, the adsorption blocks 11 of the adsorption disk 10 are put together to form the adsorption disk 10. The height of the adsorption disk 10 is controlled by the corresponding connecting ropes 13. At this time, the adsorption disk 10 and the corresponding rotating circle 20 are at the same horizontal height. The raw gas in the air inlet channel 5 flows toward the composite adsorption bed 2 in the radial direction, and flows through the adsorption disk 10 from the outside to the inside. The adsorption material in the adsorption block 11 of the outermost ring 21 is first adsorbed and saturated, and needs to slide outward to the movable frame 12. The lifting device controls the movable frame 12 to move down a small height as a whole, for example, 5-15 cm, so that the starting point of all connecting ropes 13 is higher than the end point. At the same time, under the action of the driving device of the adsorption block 11 of the outermost ring 21, the adsorption blocks 11 of the outermost ring 21 of all adsorption disks 10 slide along their respective corresponding connecting ropes 13 to the corresponding inner ring 22 of the rotating circle 20, and are fixed in position. At the same time, the adsorption blocks 11 of other rings do not move. The lifting device controls the movable frame 12 to reset, that is, to the same height as the corresponding adsorption disc 10, with the connecting rope 13 horizontal, and adsorption continues. When the adsorption blocks 11 of the secondary outer shell ring 21 are saturated with adsorption, the above operation is repeated, and the adsorption blocks 11 of the secondary outer shell ring 21 are slid to the corresponding positions of the inner shell ring 22 and fixed. As the thickness of the adsorption disc 10 decreases, the resistance of the raw gas passing through the composite adsorption bed 2 also decreases, and the corresponding adsorption material is always unsaturated, resulting in high adsorption efficiency and low energy consumption. The adsorption process is completed until all adsorption blocks 11 are saturated with adsorption and slide to the inner shell ring 22 for positioning.

[0072] At this time, the connecting cable 13 is horizontal, and the inner shell 22 rotates horizontally along the guide rail, driving the adsorption block 11 to rotate. Since the starting point of the connecting cable 13 is connected to the positioning cylinder 14, the positioning cylinder 14 also rotates at the same speed under the action of the rotating motor 15, ensuring that the connecting cable 13 does not twist or become entangled. During adsorption, the raw gas passes through the composite adsorption bed 2 from the outside to the inside, blowing the adsorption material in the adsorption block 11 toward the gas outlet channel 6. When the inner shell 22 drives the adsorption block 11 to rotate, the adsorption material in the adsorption block 11 moves outward under the action of centrifugal force, achieving the purpose of loosening and reorganizing the adsorption material, facilitating sufficient desorption.

[0073] After the inner shell ring 22 and the positioning cylinder 14 stop rotating, the desorption operation can be carried out. At this time, the adsorption blocks 11 are dispersed and arranged. Compared with desorption after being combined into the adsorption disk 10, the desorbed gas does not need to flow inward and pass through the adsorption blocks 11 of the inner shell ring 22, which reduces the gas flow resistance and avoids the desorbed gas from being re-adsorbed in small amounts on the adsorption material of the inner shell ring 22.

[0074] After desorption, the lifting device controls the movable frame 12 to move up a small height, for example, 5-15 cm, so that the starting point of all the connecting ropes 13 is lower than the end point. Then, the limiting components of the adsorption blocks 11 of the innermost shell ring 22 are loosened. Under the action of the driving device, the adsorption blocks 11 of the innermost shell ring 22 slide along their respective corresponding connecting ropes 13 to the positioning cylinder 14. The adsorption blocks 11 of the second inner shell ring 22 then slide back to the outside of the adsorption blocks 11 of the innermost shell ring 22. In this way, the adsorption blocks 11 of all the adsorption rings 17 are reset in turn and re-formed into adsorption disks 10, waiting for the next adsorption. If the adsorption oxygen production step is short, only one or several outer adsorption rings may be completely adsorbed and moved to the movable frame. In this way, when the adsorption tower enters the next adsorption oxygen production step, the remaining adsorption blocks of the adsorption bed will continue to be used.

[0075] Since the adsorption disk is composed of several adsorption circles, the outer circle of the same adsorption disk belongs to the lithium type area, the inner circle belongs to the calcium type area, and the adsorption circle in the middle belongs to the mixed area.

[0076] The adsorption circle of the calcium type zone is completely filled with Ca-LSX type molecular sieve, and the adsorption circle of the lithium type zone is completely filled with Li-LSX type molecular sieve. The volume ratio of the calcium type zone, the mixed zone and the lithium type zone is still 1:5:0.7, and the volume ratio of Ca-LSX and Li-LSX type molecular sieves in the adsorption circle of the mixed zone is both 1:1.5.

[0077] Example 8

[0078] This embodiment provides an oxygen production adsorption tower with a composite adsorption bed, which is the same as Example 7, except that the volume ratio of Ca-LSX and Li-LSX molecular sieves in the adsorption circle on the innermost side of the mixing zone (i.e., closest to the calcium type zone) is 1:1.5, and the volume ratio of Ca-LSX and Li-LSX molecular sieves in the adsorption circle on the outermost side (i.e., closest to the lithium type zone) is 1:4. The volume ratio of Ca-LSX and Li-LSX molecular sieves in the adsorption circle between the outermost and innermost sides gradually decreases linearly from the inside to the outside.

[0079] The volume ratio of the Ca-LSX to the Li-LSX molecular sieves in each adsorption block of the same adsorption circle is equal to the volume ratio of the Ca-LSX to the Li-LSX molecular sieves in the entire adsorption circle.

[0080] A dehydration zone is set between the lithium type zone and the air inlet channel. The volume ratio of the lithium type zone to the dehydration zone is 1:0.05. The adsorption circle corresponding to the dehydration zone is fully filled with 13X oxygen-making molecular sieve for dehydrating the raw gas input into the air inlet channel.

[0081] The process conditions of oxygen production by adsorption in the above embodiments and comparative examples are: adsorption pressure 1.49 bar, desorption pressure 0.4 bar, and the obtained oxygen purity is 94%. One adsorption tower is used. The adsorption tower undergoes seven basic steps: adsorption oxygen production, pressure drop, vacuum desorption, product gas flushing, pressure rise, oxygen return, and pressurization. The raw gas intake volume is 165 Nm 3 min -1 , the temperature is room temperature, the height of the composite adsorption bed is 2m, the diameter of the gas outlet channel is 0.3m, and the total radius of the composite adsorption bed and the gas outlet channel is 2m.

[0082] Table 1 Comparison of oxygen yields of Examples and Comparative Examples

[0083] Oxygen yield (%) Oxygen yield (%) Example 1 38.3 Comparative Example 2 30.1 Example 2 37.8 Example 5 38.6 Example 3 39.8 Example 6 37.4 Example 4 40.7 Example 7 41.7 Comparative Example 1 35.4 Example 8 42.6

[0084] Calculation method of oxygen yield: Oxygen yield = (gas production × oxygen composition in product) / (intake volume × oxygen composition in intake) × 100%.

[0085] As can be seen from the above table, the oxygen production adsorption tower with a composite adsorption bed of the present invention uses calcium-type and lithium-type molecular sieves in combination, which can improve the oxygen yield and thus reduce the cost of the adsorbent; the improvement of the internal structure of the adsorption tower and the ratio of the two molecular sieves in the present invention can further improve the utilization rate of the adsorption material, which is conducive to improving the oxygen yield.

Claims

1. An oxygen production adsorption tower with a composite adsorption bed, characterized in that: From top to bottom, it includes an exhaust port, a composite adsorption bed, a support plate, and an air inlet. The outer side of the composite adsorption bed is an air inlet channel, and the inner side is an air outlet channel. The top of the air outlet channel is connected to the exhaust port, and the bottom of the air inlet channel is connected to the air inlet. The composite adsorption bed is filled with adsorption materials, including Li-LSX molecular sieve and Ca-LSX molecular sieve. The portion of the composite adsorption bed close to the air inlet channel is filled entirely with Li-LSX molecular sieve, and the portion close to the air outlet channel is filled entirely with Ca-LSX molecular sieve. The volume ratio of Ca-LSX molecular sieve to Li-LSX molecular sieve in the remaining portion of the composite adsorption bed is 1:(1-5.7); The composite adsorption bed is provided with a plurality of adsorption discs from top to bottom. The adsorption discs are annular and include a plurality of adsorption rings from the outside to the inside. All the adsorption rings are concentrically arranged. The adsorption ring is composed of several adsorption blocks spliced ​​horizontally from left to right. The adsorption blocks are fan-shaped and hollow inside for filling adsorption materials. The corresponding positioning cylinder above each adsorption plate is connected to a number of connecting cables. The number of connecting cables corresponding to one adsorption plate is the same as the number of its adsorption blocks. The connecting cables pass above the center line of the corresponding adsorption block. A connecting ring is provided at the center of the upper surface of the adsorption block, so that the corresponding connecting rope passes through the connecting ring. A driving device is provided on the connecting ring for driving the adsorption block to slide along the corresponding connecting rope.

2. The oxygen production adsorption tower with a composite adsorption bed according to claim 1, characterized in that: The composite adsorption bed comprises a calcium type region, a mixed region and a lithium type region from the inside to the outside, wherein the calcium type region is entirely filled with Ca-LSX type molecular sieves, the lithium type region is entirely filled with Li-LSX type molecular sieves, and the mixed region is filled with Li-LSX type molecular sieves and Ca-LSX type molecular sieves; The volume ratio of the calcium type region, the mixed region and the lithium type region is 1:(5-8):(0.7-1.2).

3. The oxygen production adsorption tower with a composite adsorption bed according to claim 2, characterized in that: The volume ratio of the Ca-LSX molecular sieve to the Li-LSX molecular sieve in the mixing zone is 1:(1.5-4).

4. The oxygen production adsorption tower with a composite adsorption bed according to claim 3, characterized in that: A positioning cylinder is provided between the composite adsorption bed and the gas outlet channel, for defining the position of the adsorption block in the innermost shell of the adsorption disk; the positioning cylinder is a frame structure; A rotating motor is provided above the adsorption tower. The rotating shaft connected to the rotating motor penetrates into the adsorption tower and is connected to the inner side of the top of the positioning cylinder through several connecting rods, which can drive the positioning cylinder to rotate.

5. The oxygen production adsorption tower with a composite adsorption bed according to claim 4, characterized in that: A movable frame is provided in the air inlet channel. The movable frame is cylindrical and is arranged close to the inner wall of the adsorption tower. The movable frame includes a plurality of vertical rods and a plurality of rotating rings. The vertical rods are evenly arranged along the circumference of the inner wall of the adsorption tower to provide support for the rotating rings. The rotating ring is arranged on the vertical rod from top to bottom, and the rotating ring corresponds to the adsorption plate one by one; the rotating ring includes an outer shell ring and an inner shell ring. The outer side of the outer shell ring is fixedly connected to a plurality of vertical rods, and the inner side is provided with a guide rail. The inner shell ring is slidably connected to the guide rail so that the inner shell ring can rotate horizontally along the guide rail. The end points of the plurality of connecting cables are connected to corresponding positions on the inner side surface of the inner shell ring, so that the adsorption blocks of the same adsorption disk are arranged in sequence along the corresponding inner shell ring without overlapping.

6. The oxygen production adsorption tower with a composite adsorption bed according to claim 5, characterized in that: The top of the movable frame is connected to a lifting device, which is arranged on the inner wall of the adsorption tower and is used to control the vertical height of the movable frame.

7. The oxygen production adsorption tower with a composite adsorption bed according to claim 6, characterized in that: The volume ratio of Ca-LSX to Li-LSX molecular sieves in the innermost adsorption circle of the mixing zone is 1:1.5, the volume ratio of Ca-LSX to Li-LSX molecular sieves in the outermost adsorption circle is 1:4, and the volume ratio of Ca-LSX to Li-LSX molecular sieves in the adsorption circles between the outermost and innermost areas gradually decreases linearly from the inside to the outside.

8. The oxygen production adsorption tower with a composite adsorption bed according to claim 7, characterized in that: A dehydration zone is set between the lithium type zone and the air inlet channel. The volume ratio of the lithium type zone to the dehydration zone is 1: (0.05-0.1). The adsorption circle corresponding to the dehydration zone is fully filled with 13X oxygen-making molecular sieve for dehydrating the raw gas input into the air inlet channel.

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