Composite absorption tower, gas treatment system and method

Abstract

The application discloses a composite absorption tower, a gas treatment system and a method. The application is arranged with a process intensification unit and a pressure energy recovery unit below a conventional absorption tower, so that the pressure energy of the fluid under pressure is fully utilized, the liquid under pressure impacts a power impeller and drives the impeller to rotate, thereby driving a rotor assembly coaxially installed to rotate, a strong centrifugal field is provided for the process intensification reaction unit, the gas-liquid two-phase mass transfer process is greatly intensified, and the gas absorption effect is promoted. The application can recover the system energy for the intensification of the gas-liquid process, improve the gas absorption and purification effect, reduce the amount of the absorption solvent, thereby reducing the regeneration load and the energy consumption of the circulating system, ensure long-period, safe and stable operation of the device, and realize the gas purification treatment in a high-efficiency and low-cost manner.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of process intensification, and relates to a composite absorption tower, in particular to an energy recovery type composite absorption tower, a gas treatment system and a method. BACKGROUND

[0002] In petrochemical chemical production and natural gas treatment process, there are many gas treatments under medium and high pressure conditions, such as desulfurization and decarburization treatment in natural gas purification, and removal of hydrogen sulfide, carbon dioxide and other acidic components from catalytic / coking dry gas, circulating hydrogen, hydrogenated low-pressure gas and other streams in refining enterprises. At present, the above processes generally use mature alcohol amine absorption process, i.e. amine liquid "absorption-regeneration" complete technology, and the absorbent is mainly alkaline aqueous solution such as DEA, MEA, MDEA and DEPA. The typical absorption and regeneration process is that the raw gas enters from the bottom of the absorption tower, is countercurrently contacted with the solution flowing down from the top of the tower in the packing layer, the acidic gas in the gas phase is absorbed by the absorbent, the tail gas after absorption is discharged from the top of the tower, and the rich liquid after absorbing the acidic gas enters the regeneration tower. The rich liquid is regenerated in the regeneration tower to release the acidic gas, and the rich liquid is regenerated into lean liquid which is recycled back to the absorption tower after cooling.

[0003] At present, the amine liquid absorption and regeneration process generally has the following problems. First, the above absorption process generally uses tower equipment, i.e. it is carried out in a packed tower / plate tower. The traditional absorption tower has the disadvantages of poor mass transfer effect, uneven gas-liquid flow, high resistance, easy plugging of packing and unstable operation. In addition, due to the entrainment of light hydrocarbon droplets and rust scale and other impurities in the gas, the absorption liquid will have a serious foaming phenomenon, which seriously affects the long-period, safe and stable operation of the desulfurization device. At the same time, due to the low desulfurization efficiency of the absorption tower, the content of acidic components in the rich liquid is much lower than the equilibrium value, so in order to ensure the treatment effect, the amount of amine liquid is often large, the regeneration load is large, and the energy consumption is high. Therefore, it is of great significance to develop high-efficiency absorption equipment and treatment process to reduce the amount of solvent, reduce the regeneration load and the energy consumption of the circulating system, and improve the foaming phenomenon of the solvent absorption system, so as to improve the treatment effect and save energy and reduce consumption.

[0004] Patent CN112159695A discloses an energy-saving natural gas MDEA decarburization system and method. The heat grade is improved by increasing the pressure of the resolved gas output from the top of the regeneration tower, and the low-grade heat is reasonably recovered and utilized by heating the rich amine liquid entering the regeneration tower. At the same time, the resolved gas is separated after cooling, and the liquid is returned to the regeneration tower, without the need for additional regeneration tower top cooler, thereby reducing the amount of refrigerant and energy consumption. However, this technology needs to increase the resolved gas compressor equipment, which increases the power consumption, and the traditional tower equipment still has the problems of low mass transfer efficiency, low absorption liquid concentration, large amount of absorption liquid and easy foaming of the absorption liquid.

[0005] As a kind of efficient process intensification equipment, supergravity reactor realizes mass transfer process intensification by centrifugal force, compared with traditional mass transfer mode, mass transfer efficiency can be improved by orders of magnitude, with the advantages of high efficiency, small equipment volume, easy operation and easy equipment maintenance etc.Currently, supergravity technology has been applied in engineering in the fields of selective H2S removal, flue gas desulfurization and dust removal, nano powder preparation, extraction, rectification etc.In addition to having high purification effect, the technology used in amine liquid absorption system can also eliminate amine liquid foaming, and can improve amine liquid concentration to a certain extent, thereby reducing amine liquid circulation amount, greatly reducing amine liquid regeneration load and circulation system energy consumption, but the driving of supergravity reactor bed (rotor) requires motor power, which increases energy consumption.

[0006] Patent CN105385479A discloses a supergravity type desulfurization and decarbonization device integrating hydrate method and membrane method, by combining hydrate method and membrane separation method, and introducing supergravity technology on this basis, deep desulfurization and deacidification of natural gas can be realized, and the removal rate of H2S and CO2 and other acid gases in natural gas can be greatly improved.The upper half of the device is a supergravity type membrane separation unit, and the lower half of the device is a stirring type hydrate reactor, the overall structure is complex, and the rotating parts of the supergravity type steering mechanism and the magnetic stirring of the stirring type hydrate reactor all need motor drive, which increases power consumption.CN104826468A, CN104826469A, CN104826463A, CN104826466A, CN104826465A, CN104826560A and other patents use rotating bed reactor as gas-liquid reactor to treat acid gas and produce NaHS product, which can realize the dual goals of acid gas purification and pollutant resourceization, but the energy consumption of motor during operation of the rotating bed reactor is not considered. SUMMARY

[0007] The present application provides a composite absorption tower, a gas treatment system and a method. The composite absorption tower uses energy recovery system for gas-liquid process intensification, improves gas absorption purification effect, reduces absorption solvent consumption, thereby reduces regeneration load and circulation system energy consumption, ensures long-term, safe and stable operation of the device, and realizes efficient and low-cost gas purification treatment.

[0008] To achieve the above object, the first aspect of the present application provides a composite absorption tower.

[0009] The composite absorption tower comprises a tower body, a first partition, a second partition, a tower absorption unit, a process intensification unit and an energy recovery unit; the first partition and the second partition are arranged inside the tower body, and the tower body is divided into three parts from top to bottom, which are the tower absorption unit, the process intensification unit and the energy recovery unit;

[0010] The tower absorption unit comprises an air outlet, a demister, a first liquid inlet, a liquid distributor, an absorption tower section, a liquid collection tray and a liquid collection pan;

[0011] The process intensification unit comprises an air inlet, a first liquid outlet, a liquid re-distributor, a rotor assembly and a drive shaft;

[0012] The pressure energy recovery unit comprises a second liquid inlet, a second liquid outlet, a power impeller and a rotating shaft.

[0013] Further, in the composite absorption tower, the drive shaft of the process intensification unit is coaxially connected with the rotating shaft of the pressure energy recovery unit through the second partition plate.

[0014] Further, in the composite absorption tower, the first liquid outlet and the second liquid inlet are communicated through a pipeline.

[0015] Further, in the composite absorption tower, the air outlet of the tower absorption unit is arranged at the top of the tower body, the demister is arranged below the air outlet, the first liquid inlet and the liquid distributor are arranged below the demister, the inlet of the liquid distributor is connected with the first liquid inlet, the absorption tower section is arranged below the liquid distributor, and the liquid collection tray and the liquid collection pan are arranged below the absorption tower section.

[0016] Further, in the composite absorption tower, the absorption tower section is in the form of a conventional packing or tray.

[0017] Further, in the composite absorption tower, the liquid collection tray is a tray with gas lifting holes, the form of the gas lifting holes is not limited and can be in the form of a bubble cap, a float valve or other forms, to ensure that the gas can smoothly pass through, the center of the liquid collection tray is a hollow structure, the overflow weir is arranged at the edge of the hollow structure, and the lower edge of the hollow structure in the middle of the liquid collection tray is connected with the upper edge of the liquid collection pan.

[0018] Further, in the composite absorption tower, the air inlet of the process intensification unit is arranged at the middle position of the tower body of the unit, the center of the inlet is horizontally radially arranged with the rotor assembly, the first liquid outlet is arranged at the lower position of the tower body of the unit, the rotor assembly is arranged in the middle of the tower body of the unit, the liquid re-distributor is vertically arranged at the center position of the rotor assembly, and the upper end of the liquid re-distributor is connected with the lower end of the liquid collection pan.

[0019] Further, in the composite absorption tower, the liquid collection pan is connected with the upper end of the liquid re-distributor through the first partition plate, and an air phase passage is left between the liquid collection pan and the first partition plate.

[0020] Further, in the composite absorption tower, the rotor structure of the rotor assembly can be in the form of packing, disc, spiral, baffle or composite, and the rotor assembly is installed on the drive shaft.

[0021] Further, in the composite absorption tower, the second liquid inlet of the pressure energy recovery unit is arranged on the side of the unit tower body, the inlet center is horizontally radial to the power impeller assembly, and the second liquid outlet is located at the lower part or the bottom of the tower body.

[0022] Further, in the composite absorption tower, the power impeller of the pressure energy recovery unit can be a single-stage or multi-stage impeller, and the power impeller is uniformly arranged and installed on the rotating shaft along the circumference.

[0023] Further, in the composite absorption tower, the rotor assembly rotates following the driving shaft, the driving shaft rotates following the rotating shaft, the rotating shaft is driven by the power impeller, and the strong centrifugal force field generated by the rotation of the rotor is used to realize the intensification of the gas-liquid mass transfer process.

[0024] Further, in the composite absorption tower, sealing members are arranged between the rotor assembly and the reactor shell, and between the rotating shaft and the partition plate, so as to ensure that there is no leakage between the mutual areas.

[0025] The second aspect of the present application provides a gas treatment system, which comprises the composite absorption tower as described above.

[0026] A gas treatment system, which comprises a composite absorption tower, a flash tank, a lean- rich liquid heat exchanger, a regeneration tower, a lean liquid pump, a lean liquid cooler and a filtration system, wherein,

[0027] The gas inlet of the composite absorption tower is connected with a raw material gas pipeline, the gas outlet of the composite absorption tower is connected with an exhaust gas pipeline, the first liquid inlet of the composite absorption tower is connected with the outlet of the filter, and the second liquid outlet of the composite absorption tower is connected with the liquid inlet of the flash tank;

[0028] The liquid outlet of the flash tank is connected with the liquid inlet of the regeneration tower through the lean- rich liquid heat exchanger;

[0029] The gas phase outlet of the regeneration tower is connected with a regeneration gas pipeline, the liquid phase outlet of the regeneration tower is connected with the inlet of the lean liquid cooler through the lean liquid pump and the lean- rich liquid heat exchanger in sequence;

[0030] The outlet of the lean liquid cooler is connected with the inlet of the filtration system.

[0031] Further, the lean- rich liquid heat exchanger is a liquid- liquid heat exchanger, and the form of the heat exchanger is not limited.

[0032] Further, the regeneration tower is provided with a condenser at the top and a reboiler at the bottom.

[0033] Further, the first liquid outlet of the process intensification unit of the composite absorption tower is connected with the second liquid inlet of the pressure energy recovery unit.

[0034] According to a third aspect of the present application, the present application provides a gas treatment method, wherein the above-mentioned gas treatment system is applied.

[0035] Specifically, the gas treatment method comprises the following steps:

[0036] (1) The gas to be treated firstly enters the process intensification unit of the composite absorption tower, the gas contacts with the lean absorption liquid from the liquid redistributor in the rotor assembly area, the gas-liquid two-phase mass transfer is intensified and the preliminary absorption of the gas is completed, the treated gas rises to the liquid collection tray through the gas phase channel between the liquid collection tray and the first baffle, then the gas rises from bottom to top through the gas rising holes of the liquid collection tray and is discharged from the absorption unit of the composite tower, in this area, the gas is further absorbed by the lean amine absorption liquid, the lean absorption liquid enters from the liquid inlet, passes through the liquid distributor, the absorption tower section, the liquid collection tray, the liquid redistributor and the rotor assembly from top to bottom, and becomes the rich absorption liquid after absorbing the components to be treated, which is discharged from the first liquid outlet of the process intensification unit;

[0037] (2) The rich absorption liquid discharged in step (1) enters the pressure energy recovery unit of the composite absorption tower, the pressure energy of the rich absorption liquid is converted into kinetic energy, the liquid under pressure impacts the power impeller and drives the impeller to rotate, thereby driving the coaxially installed rotor assembly to rotate, and the fluid after pressure relief enters the flash tank from the second liquid outlet of the pressure energy recovery unit;

[0038] (3) The rich absorption liquid entering the flash tank in step (2) is flashed to dissolve hydrocarbons, then is heated by the lean-rich liquid heat exchanger and enters the regeneration tower, in the regeneration tower, the rich absorption liquid is heated and decomposed to release the absorbed components to become lean absorption liquid, the absorption liquid regeneration is completed, the high-concentration component gas released by the regeneration is treated subsequently, and the lean absorption liquid after regeneration is treated by the lean liquid pump, the lean-rich liquid heat exchanger, the lean liquid cooler and the filtration system, and then is returned to the composite absorption tower for recycling.

[0039] Further, the gas to be treated in step (1) can be natural gas, liquefied gas, dry gas, low-pressure gas or circulating hydrogen for the purpose of removing H2S, CO2 and other acidic components, or natural gas or other gas for the purpose of removing water, and the components to be treated are H2S, CO2 and H2O.

[0040] Further, the operating pressure of the composite absorption tower in step (1) is 0.3-20 MPa, and the operating temperature can be determined according to the specific treatment system.

[0041] Further, the rotating speed of the rotor assembly in step (1) is 50-5000 revolutions per minute (rpm), preferably 200-2000 revolutions per minute (rpm).

[0042] Further, the operation pressure of the regeneration tower in step (3) is 0.1-15 MPa, the operation pressure is lower than that of the process intensification reactor, and the operation pressure difference is 0.2-20 MPa, preferably 0.2-10 MPa; the operation temperature can be determined and adjusted according to the specific treatment system.

[0043] The gas treatment method of the present application can be used in the absorption-regeneration gas treatment field with certain pressure drop conditions, such as amine liquid desulfurization, amine liquid decarburization, MDEA selective desulfurization of hydrogen sulfide, natural gas glycol dehydration and the like.

[0044] Compared with the prior art, the present application has the following beneficial effects:

[0045] 1. The process intensification unit and the pressure energy recovery unit are arranged below the conventional absorption tower, the pressure energy of the fluid under pressure is fully utilized, the liquid under pressure impacts the power impeller and drives the impeller to rotate, thereby driving the rotor assembly coaxially installed to rotate, providing a strong centrifugal field for the process intensification reaction unit, greatly strengthening the gas-liquid two-phase mass transfer process, and promoting the gas absorption effect.

[0046] 2. Compared with the existing tower equipment, the process intensification unit of the composite absorption tower greatly strengthens the gas-liquid mass transfer process, equivalent to adding a pre-absorption section before the conventional absorption tower treatment, increasing a centrifugal field to strengthen the absorption process, reducing the load of the absorption tower, greatly reducing the volume of the absorption tower equipment, and saving the capital construction and equipment investment.

[0047] 3. The present application fully recovers the pressure energy of the liquid under pressure before depressurization and regeneration, and uses it as the energy to drive the rotor assembly, thereby realizing the intensification of the absorption process, having the advantages of supergravity equipment, and solving the motor energy consumption problem of the supergravity reactor by using the system pressure energy, thereby realizing the gas treatment with high efficiency and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 A composite absorption tower according to the present application is shown in the figure.

[0049] In the figure, 1 is a tower body, 2 is a first partition, 3 is a second partition, 4 is a tower absorption unit, 5 is a process intensification unit, 6 is an energy recovery unit, 7 is a gas outlet, 8 is a demister, 9 is a first liquid inlet, 10 is a liquid distributor, 11 is an absorption tower section, 12 is a liquid collection tray, 13 is a liquid collection tray, 14 is a gas inlet, 15 is a first liquid outlet, 16 is a liquid redistribution device, 17 is a rotor assembly, 18 is a driving shaft, 19 is a second liquid inlet, 20 is a second liquid outlet, 21 is a power impeller, 22 is a rotating shaft, 23 is a gas lifting hole, and 24 is an overflow weir.

[0050] Figure 2 A schematic diagram of a gas treatment system according to the present application.

[0051] In the figure, 51 is a raw gas pipeline, 52 is a composite absorption tower, 53 is an exhaust gas pipeline, 54 is a filter, 55 is a flash tank, 56 is a rich absorption liquid pipeline, 57 is a rich-lean liquid heat exchanger, 58 is a regeneration tower, 59 is a regeneration gas pipeline, 60 is a lean liquid pump, 61 is a lean absorption liquid pipeline, 62 is a lean liquid cooler, and 63 is a flash gas pipeline. DETAILED DESCRIPTION

[0052] The composite absorption tower, gas treatment system and method of the present application will be described in detail below with reference to the accompanying drawings and examples, but the present application is not limited thereto. Example 1

[0053] This embodiment describes a composite absorption tower according to the present application in detail. As shown in the figure, the structure of a composite absorption tower according to the present application is as follows: Figure 1

[0054] ​The composite absorption tower comprises a tower body 1, a first partition plate 2, a second partition plate 3, a tower absorption unit 4, a process intensification unit 5 and an energy recovery unit 6. The first partition plate 2 and the second partition plate 3 are arranged inside the tower body 1, and divide the tower body into three parts from top to bottom, namely the tower absorption unit 4, the process intensification unit 5 and the energy recovery unit 6. The tower absorption unit 4 comprises an air outlet 7, a demister 8, a first liquid inlet 9, a liquid distributor 10, an absorption tower section 11, a liquid collecting tower plate 12 and a liquid collecting disc 13. The process intensification unit 5 comprises an air inlet 14, a first liquid outlet 15, a liquid redistribution device 16, a rotor assembly 17 and a driving shaft 18. The energy recovery unit 6 comprises a second liquid inlet 19, a second liquid outlet 20, a power impeller 21 and a rotating shaft 22. The driving shaft 18 of the process intensification unit 5 and the rotating shaft 22 of the energy recovery unit 6 are coaxially connected through the second partition plate 3. The first liquid outlet 15 and the second liquid inlet 19 are communicated through a pipeline. The air outlet 7 of the tower absorption unit 4 is arranged at the top of the tower body 1, the demister 8 is arranged below the air outlet 7, the first liquid inlet 9 and the liquid distributor 10 are arranged below the demister 8, the inlet of the liquid distributor 10 is connected with the first liquid inlet 9, the absorption tower section 11 is arranged below the liquid distributor 10, and the liquid collecting tower plate 12 and the liquid collecting disc 13 are arranged below the absorption tower section 11. The liquid collecting tower plate 12 in the composite absorption tower is a tower plate with gas lifting holes 23, the center of the liquid collecting tower plate 12 is a hollow structure, an overflow weir 24 is arranged at the edge of the hollow structure, and the lower edge of the middle hollow part is connected with the upper edge of the liquid collecting disc 13. The air inlet 14 of the process intensification unit 5 is arranged at the middle position of the tower body of this unit, the center of the inlet is horizontally radial to the rotor assembly 17, the first liquid outlet 15 is arranged at the lower position of the tower body of this unit, the rotor assembly 17 is arranged at the middle position of the tower body of this unit, the liquid redistribution device 16 is vertically arranged at the center position of the rotor assembly 17, and the upper end of the liquid redistribution device 16 is connected with the lower end of the liquid collecting disc 13. The liquid collecting disc 13 is connected with the upper end of the liquid redistribution device 16 through the first partition plate 2, and a gas phase channel is left between the liquid collecting disc 13 and the first partition plate 2. The rotor assembly 17 is installed on the driving shaft 18. The second liquid inlet 19 of the pressure energy recovery unit 5 is arranged at the side of the tower body of this unit, the center of the inlet is horizontally radial to the power impeller 21 assembly, and the second liquid outlet 20 is arranged at the lower part or the bottom of the tower body. The power impeller 21 of the energy recovery unit 6 is uniformly arranged and installed on the rotating shaft 22 along the circumference. When the composite absorption tower works, the rotor assembly 17 rotates with the driving shaft 18, the driving shaft 18 rotates with the rotating shaft 22, and the rotating shaft 22 is driven by the power impeller 21. The gas-liquid mass transfer process is intensified by using the strong centrifugal force field generated by the rotation of the rotor. Example 2

[0055] The embodiment describes a gas treatment system of the present application.

[0056] AsFigure 2 As shown in the figure, the present application provides a gas treatment system, which comprises a composite absorption tower 52, a flash tank 55, a lean- rich liquid heat exchanger 57, a regeneration tower 58, a lean liquid pump 60, a lean liquid cooler 62 and a filter system 54. The gas inlet of the composite absorption tower 52 is connected with a raw gas pipeline 51, the gas outlet of the composite absorption tower 52 is connected with an exhaust gas pipeline 53, the first liquid inlet 9 of the composite absorption tower 52 is connected with the outlet of the filter system 54, the second liquid outlet 20 of the composite absorption tower is connected with the liquid inlet of the flash tank 55. The liquid outlet of the flash tank 55 is connected with the liquid inlet of the regeneration tower 58 through the lean- rich liquid heat exchanger 57. The gas phase outlet of the regeneration tower 58 is connected with a regeneration gas pipeline 59, and the liquid phase outlet of the regeneration tower 58 is connected with the inlet of the lean liquid cooler 62 after passing through the lean liquid pump 60 and the lean- rich liquid heat exchanger 57. The outlet of the lean liquid cooler 62 is connected with the inlet of the filter system 54. The first liquid outlet 15 of the process intensification unit 5 of the composite absorption tower 52 is connected with the second liquid inlet 19 of the pressure energy recovery unit 6. Example 3

[0057] The present embodiment describes the gas treatment method of the present application in detail. In combination with the above description of the composite absorption tower, the working process of the gas treatment system and method provided by the present application is as follows: Figures 1-2

[0058] ​The gas to be treated first enters the process enhancement unit 5 of the composite absorption tower 52 through the inlet pipeline 51. In the rotor assembly 17 area, the gas contacts the lean absorbent from the liquid redistributor 16, undergoing a gas-liquid two-phase mass transfer enhancement process and completing the initial gas absorption. The treated gas rises to the collection tray 12 through the gas phase channel between the collection tray 13 and the first partition plate 2, and then exits from bottom to top through the tower absorption unit 4 of the composite tower via the riser hole 23 of the collection tray 12. In this area, the gas is further absorbed by the lean amine absorbent. The lean absorbent enters from the inlet 9 and passes from top to bottom through the liquid distributor 10, the absorption tower section 11, the collection tray 13, the liquid redistributor 16, and the rotor assembly 17. After absorbing the components to be treated, it becomes a rich absorbent and is discharged from the first drain port 15 of the process enhancement unit 5. The discharged rich absorbent... The collected liquid enters the pressure energy recovery unit 6 of the composite absorption tower 52, where the pressure energy of the rich absorbent is converted into kinetic energy. This kinetic energy is used to drive the impeller 21 through the pressurized liquid, which in turn drives the coaxially mounted rotor assembly 17 to rotate. The depressurized fluid enters the flash tank 55 through the second drain port 20 of the pressure energy recovery unit 6. After the rich absorbent flashes out dissolved hydrocarbons in the flash tank 55, it is heated by the lean-rich liquid heat exchanger 57 and enters the regeneration tower 58. In the regeneration tower 58, the rich absorbent is heated and decomposed to release the absorbed components, becoming lean absorbent, thus completing the regeneration of the absorbent. The high-concentration component gas released during regeneration is then subjected to further treatment. The regenerated lean absorbent is pressurized by the lean liquid pump 60, cooled by the lean-rich liquid heat exchanger 57, cooled by the lean liquid cooler 62, and filtered by the filtration system 54 before being returned to the composite absorption tower 52 for recycling. Example 4

[0059] This embodiment provides a specific application example of a gas processing system according to the present invention.

[0060] use Figure 1 The present invention provides a composite absorption tower, and selects... Figure 2The shown gas treatment system is used for decarburization treatment of natural gas from a gas field. The CO2 concentration in the natural gas is about 8% (V). The mixed amine absorption liquid of MDEA 35% + DEA 10% + H2O 55% (mass concentration) is used for treatment. The absorption pressure is 8 MPa. The absorption temperature is 45℃. The regeneration pressure is 0.8 MPa. The regeneration temperature is 130℃. The carbon-containing natural gas firstly enters the process intensification unit 5 of the composite absorption tower 52. The gas is contacted with the lean amine absorption liquid from the liquid redistributor 16 in the rotor assembly 17 area to complete the CO2 gas preliminary absorption by the gas-liquid two-phase mass transfer intensification process. The treated natural gas rises through the composite tower absorption unit 4 via the liquid collection tower plate 12. The gas is further absorbed and treated by the lean amine absorption liquid in this area. The CO2 concentration in the treated natural gas can be less than 0.5% (V). The lean absorption liquid passes through the liquid distributor 10, the absorption tower section 11, the liquid collection disc 13, the liquid redistributor 16 and the rotor assembly 17 from top to bottom. The CO2 gas absorbed by the lean absorption liquid becomes the rich absorption liquid which is discharged from the first liquid outlet 15 of the process intensification unit 5. Subsequently, the rich absorption liquid enters the pressure energy recovery unit 6 of the composite absorption tower 52. The rich absorption liquid is reduced from 8 MPa to about 1.2 MPa, and the pressure energy possessed by the rich absorption liquid is converted into kinetic energy. The rich absorption liquid impacts the dynamic impeller 21 under pressure and drives the impeller to rotate, thereby driving the coaxially installed rotor assembly 17 to rotate. The rich absorption liquid after pressure relief enters the flash tank 55 to flash out the dissolved hydrocarbon, and then enters the regeneration tower 58 after being warmed by the heat exchanger 57. In the regeneration tower 58, the rich absorption liquid is heated and decomposed to release the absorbed components to become lean absorption liquid. The absorption liquid regeneration is completed. The high-concentration CO2 gas released by the regeneration is treated subsequently. The lean absorption liquid after regeneration is treated by pressurization, heat exchange, cooling and filtration, and then returned to the composite absorption tower 52 for recycling.

[0061] Comparative Example 1

[0062] The same as Example 1, except that the natural gas decarburization equipment uses a traditional tower type equipment. The gas-liquid contact process of the traditional tower is carried out in the normal gravity field. Due to the limitation of the gravity field, the gas-liquid contact flow is slow, the mass transfer coefficient is not high, and the mass transfer rate is low, resulting in that the acid component content in the rich liquid is far lower than the equilibrium value. Compared with Example 1, the tower height of this comparative example increases by 30%, and the amine liquid consumption and regeneration energy consumption increase by about 20% to achieve the same treatment effect.

[0063] Comparative Example 2

[0064] The same as example 1, except that the natural gas decarburization equipment adopts a conventional supergravity equipment, the driving of the traditional supergravity reactor bed (rotor) needs a motor to provide power, under the same operating conditions as example 1, the power consumption of the system is increased by more than 30%, and the process intensification unit and the pressure energy recovery unit are arranged below the conventional absorption tower in example 1, the system pressure energy is used to solve the motor energy consumption problem caused by the centrifugal field provided by the supergravity equipment, and the natural gas purification is realized efficiently and at low cost.

Claims

1. A composite absorption tower, characterized in that, The composite absorption tower includes a tower body, a first baffle, a second baffle, a tower absorption unit, a process enhancement unit, and an energy recovery unit; The first and second partitions are located inside the tower body, dividing the tower body into three parts from top to bottom: the tower absorption unit, the process enhancement unit, and the energy recovery unit. The tower absorption unit includes an air outlet, a demister, a first liquid inlet, a liquid distributor, an absorption tower section, a liquid collection tray, and a liquid collection pan. The process enhancement unit includes an air inlet, a first drain outlet, a liquid redistributor, a rotor assembly, and a drive shaft; The energy recovery unit includes a second liquid inlet, a second liquid outlet, a power impeller, and a rotating shaft; The first drain port and the second inlet port are connected by a pipe; The power impeller is a single-stage or multi-stage impeller, and the power impellers are evenly arranged and installed on the rotating shaft along the circumference.

2. The composite absorption tower according to claim 1, characterized in that, The drive shaft of the process enhancement unit and the rotation shaft of the energy recovery unit are coaxially connected through the second partition.

3. The composite absorption tower according to claim 1, characterized in that, The gas outlet of the tower absorption unit is located at the top of the tower body, the demister is located below the gas outlet, the first liquid inlet and the liquid distributor are located below the demister, the inlet of the liquid distributor is connected to the first liquid inlet, the absorption tower section is located below the liquid distributor, and the liquid collection tray and liquid collection plate are located below the absorption tower section.

4. The composite absorption tower according to claim 1, characterized in that, The liquid collecting tray is a tray with air rising holes. The center of the liquid collecting tray is a hollow structure, and an overflow weir is provided at the hollow edge. The lower edge of the hollow part in the middle of the liquid collecting tray is connected to the upper edge of the liquid collecting pan.

5. The composite absorption tower according to claim 1, characterized in that, The air inlet of the process enhancement unit is located in the middle of the unit tower, with the center of the inlet radially horizontal to the rotor assembly. The first drain outlet is located at the lower part of the unit tower. The rotor assembly is located in the middle of the unit tower. The liquid redistributor is vertically located at the center of the rotor assembly, and the upper end of the liquid redistributor is connected to the lower end of the liquid collection tray.

6. The composite absorption tower according to claim 1, characterized in that, The liquid collection tray passes through the first partition and is connected to the upper end of the liquid redistributor, and a gas phase channel is left between the liquid collection tray and the first partition.

7. The composite absorption tower according to claim 1, characterized in that, The rotor assembly is mounted on the drive shaft.

8. The composite absorption tower according to claim 1, characterized in that, The second liquid inlet of the energy recovery unit is located on the side of the tower body of this unit, with the center of the inlet radially horizontal to the power impeller assembly, and the second liquid outlet is located at the lower part or bottom of the tower body.

9. The composite absorption tower according to claim 1, characterized in that, Sealing components are installed between the rotor assembly and the reactor shell, and between the rotating shaft and the partition plate, to ensure that there is no leakage in the respective areas.

10. A gas processing system, characterized in that, Includes the composite absorption tower according to any one of claims 1-9.

11. The gas handling system according to claim 10, characterized in that, The system includes a composite absorption tower, a flash tank, a lean and rich liquor heat exchanger, a regeneration tower, a lean liquor pump, a lean liquor cooler, and a filtration system; wherein, The gas inlet of the composite absorption tower is connected to the raw material gas pipeline, the gas outlet of the composite absorption tower is connected to the exhaust gas pipeline, the first liquid inlet of the composite absorption tower is connected to the filter outlet, and the second liquid outlet of the composite absorption tower is connected to the liquid inlet of the flash tank. The liquid outlet of the flash tank is connected to the liquid inlet of the regeneration tower via a lean-rich liquid heat exchanger. The gas phase outlet of the regeneration tower is connected to the regeneration gas pipeline, and the liquid phase outlet of the regeneration tower is connected to the inlet of the lean liquid cooler after passing through the lean liquid pump and the lean and rich liquid heat exchanger. The outlet of the lean liquid cooler is connected to the inlet of the filtration system.

12. The gas handling system according to claim 11, characterized in that, The first drain port of the process enhancement unit of the composite absorption tower is connected to the second inlet of the energy recovery unit.

13. A gas treatment method, characterized in that, The gas processing system according to any one of claims 10-12 is applied.

14. The gas treatment method according to claim 13, characterized in that, Includes the following steps: (1) The gas to be treated first enters the process enhancement unit of the composite absorption tower. The gas comes into contact with the lean absorbent from the liquid redistributor in the rotor assembly area, and the gas-liquid two-phase mass transfer enhancement process is carried out and the gas is initially absorbed. The gas to be treated rises to the liquid collection plate through the gas phase channel between the liquid collection plate and the first partition plate, and then is discharged from the tower absorption unit of the composite tower through the gas rise hole of the liquid collection plate from bottom to top. In this area, the gas is further absorbed and treated by the lean amine absorbent. The lean absorbent enters from the inlet and passes through the liquid distributor, absorption tower section, liquid collection plate, liquid redistributor and rotor assembly from top to bottom. After absorbing the components to be treated, it becomes a rich absorbent and is discharged from the first drain port of the process enhancement unit. (2) The rich absorbent discharged in step (1) enters the energy recovery unit of the composite absorption tower. The pressure energy of the rich absorbent is converted into kinetic energy. The pressurized liquid impacts the power impeller and drives the impeller to rotate, thereby driving the coaxially mounted rotor assembly to rotate. The depressurized fluid enters the flash tank through the second drain port of the pressure energy recovery unit. (3) After the dissolved hydrocarbons in the rich absorbent entering the flash tank in step (2) are flashed, the rich absorbent is heated by the rich-lean heat exchanger and enters the regeneration tower. In the regeneration tower, the rich absorbent is heated and decomposed to release the absorbed components and become the lean absorbent, thus completing the regeneration of the absorbent. The high-concentration component gas released by the regeneration is then processed. The regenerated lean absorbent is pressurized by the lean absorbent pump, cooled by the rich-lean heat exchanger, cooled by the lean absorbent cooler, and filtered by the filtration system before being returned to the composite absorbent for recycling.

15. The gas treatment method according to claim 14, characterized in that, The gas to be treated contains one or more of H2S, CO2, and H2O.

16. The gas treatment method according to claim 14, characterized in that, The operating pressure of the composite absorption tower in step (1) is 0.3~20 MPa.

17. The gas treatment method according to claim 14, characterized in that, The operating pressure of the regeneration tower in step (3) is lower than that of the process enhancement reactor, with a pressure difference of 0.2~20 MPa.

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