Micro-channel equipment for strengthening gas absorption process

Abstract

The invention provides micro-channel equipment for strengthening a gas absorption process, and belongs to the field of gas absorption equipment. The micro-channel equipment comprises an upper cover plate, a reactor plate and a lower cover plate which are hermetically connected in sequence, wherein the reactor plate comprises an absorbent inlet channel, a gas inlet channel, a reaction liquid outlet channel, an absorbent parallel distribution channel, a gas parallel distribution channel, a reaction liquid parallel outlet channel and a fluid mixing channel. The micro-channel equipment is applied to gas absorption and removal, the gas treatment amount can be effectively increased by simply increasing the number of fluid mixing channels or the number of the micro-channel equipment, and compared with traditional equipment such as a float valve tower and a packed tower, the micro-channel equipment is small in size, the mass transfer efficiency can be improved by 10-100 times or above, and the micro-channel equipment has the same scale and can be applied to gas absorption and removal. And the use amount of the absorbent can be saved by about 15%. Meanwhile, the equipment is good in sealing performance, and the problems of flooding, entrainment, liquid leakage and the like can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of absorption devices, and in particular relates to a microchannel device for strengthening a gas absorption process. Background Art

[0002] In the current industrial gas absorption process, the alcoholamine process occupies a dominant position. Its process mainly involves gas-liquid contact between gas and alcoholamine solution. The solvent used is usually MDEA solution, which has the advantages of large absorption load and lower regeneration energy compared with traditional DGA. The aMDEA solution developed by BASF and the Sulfinol process solution of Shell are both of this type. The gas-liquid contact equipment with more applications mainly includes spray towers, wet wall towers, packed towers, bubble towers, plate towers, jet reactors, etc., which have simple structures, easy operation, and can handle large gas flows. However, such equipment has the problems of large footprint, large amount of absorbent required, low mass transfer efficiency, and high regeneration energy consumption. There are also problems such as mist entrainment, liquid flooding, and liquid leakage.

[0003] In recent years, technologies such as ultra-gravity packed beds, new membrane contactors, and micro-mixers have emerged to enhance the interphase mass transfer between amine liquid and gas. Ultra-gravity packed beds use rotating nozzles to produce small droplets, which contact with the gas through countercurrent rotating packing, greatly increasing the gas-liquid two-phase interface. Its liquid mass transfer coefficient is 3 to 7 times that of traditional equipment, but the equipment requires external energy and has high requirements for bearing seals, and the operating and investment costs are high. The membrane contactor uses a membrane as the gas-liquid contact interface, and the gas contacts the liquid through the membrane. Generally, a hollow fiber membrane is used, which has a huge specific surface area, but the membrane contactor has a large mass transfer resistance and is not suitable for high pressure and systems where organic solvents easily swell the membrane material.

[0004] Microchannel technology, as a process intensification technology developed in recent years, has attracted more and more attention. It has various forms and a specific surface area far larger than traditional packed tower equipment. It is also resistant to high pressure and corrosion and has safe performance. At present, some of it has been applied to reaction control, mass transfer enhancement and hazardous chemical synthesis. Foreign chemical companies such as Dupont, IMM, BASF, Bayer, Merck, Shell, UOP and others have made arrangements. It is regarded as one of the most promising chemical process intensification technologies in the future.

[0005] Patents CN108854465A and CN103372370A disclose two processes for carbon dioxide absorption using microchannels, respectively, which can reduce the carbon dioxide concentration to 50ppm and the solvent can be recycled, but they use existing microchannel equipment and do not solve the problems of microchannel amplification and structure. Patent CN101612510A reports a microchannel absorber, which mixes the gas containing carbon dioxide with the absorbent and injects it into the microchannel body through a solid uniform distributor for mass transfer. The structure is relatively complex, and the packaging of the microchannel equipment is difficult to control the seal intact. At the same time, the gas and liquid inlet and outlet devices are difficult to enlarge, and the processing volume cannot be increased simply by increasing the number. Patent CN101612511A discloses a microchannel absorber, which mixes the gas containing hydrogen sulfide with the amine liquid and injects it into the microchannel body through a solid uniform distributor for mass transfer. The structure is relatively complex and the gas and liquid inlet and outlet devices are difficult to enlarge, and the processing volume cannot be increased simply by increasing the number. Summary of the invention

[0006] The purpose of the present invention is to provide a microchannel device for enhancing the gas absorption process, which is simple to manufacture and has good sealing performance. It can effectively improve the mass transfer efficiency between the gas and the absorbent and reduce the amount of absorbent used. At the same time, without affecting the gas absorption effect, the device processing capacity can be quickly increased by increasing the number of units.

[0007] The microchannel device involved in the present invention is suitable for capturing carbon dioxide in boiler flue gas, FCC flue gas, synthesis gas and blast furnace gas to reduce carbon emissions and obtain higher concentration carbon dioxide raw materials. It is also suitable for removing hydrogen sulfide from dry gas, liquefied gas and gas produced by hydrocracking, coking, hydrofining and other devices in refineries to meet environmental emissions and subsequent process requirements.

[0008] In order to achieve the above object, the technical solution adopted by the present invention includes:

[0009] A microchannel device for enhancing a gas absorption process, the microchannel device comprising an upper cover plate 1, a reactor plate 2 and a lower cover plate 3 connected in sequence;

[0010] The upper and lower surfaces of the reactor plate 2 are respectively provided with fluid mixing channels 10;

[0011] The interior of the reactor plate 2 is provided with absorbent parallel distribution channels 7, gas parallel distribution channels 8 and reaction liquid parallel outlet channels 9 in sequence along the flow direction in the fluid mixing channel 10;

[0012] The reactor plate 2 is also provided with an absorbent inlet channel 4, a gas inlet channel 5 and a reaction liquid outlet channel 6;

[0013] Among them, the absorbent inlet channel 4 is connected to the fluid mixing channel 10 via the absorbent parallel distribution channel 7, the gas inlet channel 5 is connected to the fluid mixing channel 10 via the gas parallel distribution channel 8, and the fluid mixing channel 10 is connected to the reaction liquid outlet channel 6 via the reaction liquid parallel outlet channel 9.

[0014] The connection method of the upper cover plate 1, the reactor plate 2 and the lower cover plate 3 of the present invention is not limited, and bolts or other fastening methods can be used.

[0015] Optionally, the fluid mixing channel 10 has a width of 3 to 5 mm, a length of 60 to 300 mm, and a depth of 0.1 to 2 mm.

[0016] Optionally, the width of the fluid mixing channel 10 is 3.5 mm, 4.0 mm, 4.2 mm, 4.5 mm or 4.8 mm, or any value between any two of the above points.

[0017] Optionally, the length of the fluid mixing channel 10 is 70 mm, 80 mm, 90 mm, 100 mm, 120 mm, 150 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 260 mm or 280 mm, or any value between any two of the above points.

[0018] Optionally, the depth of the fluid mixing channel 10 is 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm or 1.8 mm, or any value between any two of the above points.

[0019] Optionally, the distance between the absorbent parallel distribution channel 7 and the gas parallel distribution channel 8 along the flow direction in the fluid mixing channel (10) is 30 to 50 mm.

[0020] Optionally, the distance between the absorbent parallel distribution channel 7 and the gas parallel distribution channel 8 is 32 mm, 34 mm, 35 mm, 36 mm, 38 mm, 40 mm, 42 mm, 45 mm or 48 mm, or any value between any two of the above points.

[0021] Optionally, the number of fluid mixing channels 10 on the upper surface and the lower surface of the reactor plate 2 is independently 2 to 15.

[0022] Optionally, the number of fluid mixing channels 10 on the upper surface and the lower surface of the reactor plate 2 is the same, and is 2 to 15.

[0023] Optionally, the number of the fluid mixing channels 10 is 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14.

[0024] Optionally, on the upper surface and the lower surface of the reactor plate 2 , the interval between two adjacent fluid mixing channels 10 is 3 to 5 mm.

[0025] Optionally, the reactor plate 2 contains 1 to 4 rows, for example 2 to 4 rows, of gas parallel distribution channels 8 arranged along the flow direction in the fluid mixing channel 10 .

[0026] In the present invention, when the reactor plate 2 contains multiple rows of gas parallel distribution channels 8 , the distance between the absorbent parallel distribution channels 7 and the gas parallel distribution channels 8 refers to the distance between the absorbent parallel distribution channels 7 and the adjacent first row of gas parallel distribution channels 8 .

[0027] Optionally, the interval between two adjacent rows of gas parallel distribution channels 8 is 2 to 5 mm.

[0028] Optionally, the diameter of the absorbent parallel distribution channel 7 is 3 to 5 mm.

[0029] Optionally, the diameter of the reaction liquid parallel outlet channel 9 is 3 to 5 mm.

[0030] Optionally, the diameter of the gas parallel distribution channel 8 is 1 to 3 mm.

[0031] Optionally, the absorbent inlet channel 4 and the gas inlet channel 5 are arranged on the same side of the reactor plate 2, and are located on the central axis in the thickness direction, and the reaction liquid outlet channel 6 is arranged on the other side of the reactor plate 2 opposite to the absorbent inlet channel 4, and is located on the central axis in the thickness direction.

[0032] The present invention has the following beneficial effects:

[0033] The microchannel device of the present invention is applied to the absorption and removal of gas. By simply increasing the number of fluid mixing channels or the number of the microchannel device, the gas processing capacity can be effectively expanded, and the traditional floating valve tower, packed tower, etc. can be effectively replaced. Compared with the traditional floating valve tower, packed tower, etc., the device is small in size, and the mass transfer efficiency can be increased by more than 10 to 100 times. At the same scale, the amount of absorbent used can be saved by about 15%, and the energy consumption of absorbent regeneration is further effectively reduced. At the same time, the device has good sealing performance and can effectively solve the problems of liquid flooding, mist entrainment and liquid leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the microchannel device of the present invention;

[0035] Among them, A, B, and C are cross-sectional views of three corresponding positions, 1 is the upper cover plate, 2 is the reactor plate, 3 is the lower cover plate, 4 is the absorbent inlet channel, 5 is the gas inlet channel, 6 is the reaction liquid outlet channel, 7 is the absorbent parallel distribution channel, 8 is the gas parallel distribution channel, 9 is the reaction liquid parallel outlet channel, and 10 is the fluid mixing channel. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0037] A microchannel device, the device is composed of an upper cover plate 1, a reactor plate 2 and a lower cover plate 3 which are tightly connected in sequence, the upper cover plate 1 and the lower cover plate 3 are two smooth flat plates; the upper surface and the lower surface of the reactor plate 2 are symmetrically provided with a plurality of fluid mixing channels 10; the interior of the reactor plate 2 is provided with a plurality of absorbent parallel distribution channels 7, a plurality of gas parallel distribution channels 8 and a plurality of reaction liquid parallel outlet channels 9 in sequence along the flow direction in the fluid mixing channel 10; the reactor plate 2 is also provided with an absorbent inlet channel 4, a gas inlet channel 5 and a reaction liquid outlet channel 6;

[0038] Among them, the absorbent inlet channel 4 is connected with multiple absorbent parallel distribution channels 7, and the absorbent parallel distribution channels 7 are respectively connected with multiple fluid mixing channels 10; the gas inlet channel 5 is connected with multiple gas parallel distribution channels 8, and the gas parallel distribution channels 8 are respectively connected with multiple fluid mixing channels 10; the fluid mixing channels 10 are respectively connected with multiple reaction liquid parallel outlet channels 9, and the multiple reaction liquid parallel outlet channels 9 are connected with the reaction liquid outlet channel 6.

[0039] The operation process of the present invention is as follows:

[0040] First, the upper cover plate, reactor plate and lower cover plate of the microchannel device are connected by bolts, and then the absorbent is connected to the microchannel device through a delivery pipeline, a pump, etc., and the gas to be absorbed is connected to the microchannel device through a delivery pipeline, a valve, a compressor, etc., and the outlet of the microchannel device is connected to a buffer tank through a pipeline to achieve gas-liquid separation. During operation, the absorbent enters the microchannel device through the absorbent inlet channel, and then is divided into multiple strands through the absorbent parallel distribution channel and enters each fluid mixing channel respectively; the gas to be absorbed is injected through the gas inlet channel, and then is divided into multiple strands through the gas parallel distribution channel and enters each fluid mixing channel. The gas to be absorbed will be sheared by the absorbent during the process of entering the fluid mixing channel, thereby forming small bubbles or liquid columns. At the same time, the gas and liquid phases will be dragged by the boundary layer during the movement of the fluid mixing channel, thereby enhancing the mass transfer between the two phases. Then the gas and liquid will merge through the parallel outlet channel of the reaction liquid and discharge from the microchannel device through the absorbent outlet channel. In this process, the interface disturbance between the two phases is enhanced, and the mass transfer process is further enhanced, thereby achieving the use of less absorbent to absorb and separate the corresponding gas.

[0041] Example 1

[0042] In this embodiment, the specifications of the upper cover plate 1 and the lower cover plate 3 are 350 mm long ╳ 120 mm wide ╳ 3 mm thick, the specifications of the reactor plate 2 are 350 mm long ╳ 120 mm wide ╳ 20 mm thick, the number of fluid mixing channels 10 is 8, the width is 3 mm, the length is 150 mm, the depth is 2 mm, the interval between every two fluid mixing channels 10 is 3 mm, the diameters of the absorbent parallel distribution channels 7 and the reaction liquid parallel outlet channels 9 are both 3 mm, the diameter of the gas parallel distribution channels 8 is 2 mm, and in this example, three rows of gas parallel distribution channels 8 are provided, the distance between the absorbent parallel distribution channels 7 and the adjacent gas parallel distribution channels 8 is 30 mm, and the interval between every two rows of gas parallel distribution channels 8 is 2 mm.

[0043] The experiment used power plant flue gas containing 12% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50°C, the pressure was 0.5Mpa, and the gas-liquid volume flow ratio was 50:1, the decarbonization rate was 87.2%.

[0044] Example 2

[0045] The same microchannel device as in Example 1 was used, wherein the length of the fluid mixing channel was 300 mm.

[0046] The experiment used power plant flue gas containing 12% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50°C, the pressure was 0.5Mpa, and the gas-liquid volume flow ratio was 50:1, the decarbonization rate was 89.5%.

[0047] Example 3

[0048] The same microchannel device as in Example 1 was used, wherein the length of the fluid mixing channel was 250 mm.

[0049] The experiment used power plant flue gas containing 12% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50°C, the pressure was 0.5Mpa, and the gas-liquid volume flow ratio was 50:1, the decarbonization rate was 88.3%.

[0050] Example 4

[0051] The same microchannel device as in Example 1 was used, wherein the fluid mixing channel had a length of 300 mm and a depth of 0.1 mm.

[0052] The experiment used power plant flue gas containing 12% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50°C, the pressure was 0.5Mpa, and the gas-liquid volume flow ratio was 50:1, the decarbonization rate was 99.2%.

[0053] Example 5

[0054] The same microchannel device as in Example 1 was used, wherein the fluid mixing channel had a length of 300 mm and a depth of 1 mm.

[0055] The experiment used power plant flue gas containing 12% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50°C, the pressure was 0.5Mpa, and the gas-liquid volume flow ratio was 50:1, the decarbonization rate was 93.4%.

[0056] Example 6

[0057] The same microchannel device as in Example 1 was used, wherein the fluid mixing channel had a length of 300 mm and a width of 5 mm.

[0058] The experiment used power plant flue gas containing 12% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50℃, the pressure was 0.5Mpa, the gas-liquid volume flow ratio was 80:1, and the decarbonization rate was 80.1%.

[0059] Example 7

[0060] The same microchannel equipment as in Example 1 was used.

[0061] The experiment used synthesis gas containing 31% CO2, the absorbent was 25wt.% MDEA aqueous solution, to which 3% piperazine was added, the operating temperature was 50°C, the pressure was 0.5Mpa, and the gas-liquid volume flow ratio was 50:1, the decarbonization rate was 82.4%.

[0062] Example 8

[0063] In this embodiment, the specifications of the upper cover plate 1 and the lower cover plate 3 are 120 mm long ╳ 120 mm wide ╳ 3 mm thick, the specifications of the reactor plate 2 are 120 mm long ╳ 120 mm wide ╳ 20 mm thick, the number of fluid mixing channels 10 is 5, the width is 5 mm, the length is 60 mm, the depth is 2 mm, the interval between every two fluid mixing channels 10 is 5 mm, the diameters of the absorbent parallel distribution channels 7 and the reaction liquid parallel outlet channels 9 are both 3 mm, the diameter of the gas parallel distribution channels 8 is 2 mm, and in this embodiment, three rows of gas parallel distribution channels 8 are provided, the distance between the absorbent parallel distribution channels 7 and the adjacent gas parallel distribution channels 8 is 30 mm, and the interval between every two rows of gas parallel distribution channels 8 is 2 mm.

[0064] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, the gas-liquid volume flow ratio was 600:1, and the desulfurization rate was 80.7%.

[0065] Example 9

[0066] The same microchannel device as in Example 8 was used, wherein the depth of the fluid mixing channel was 0.1 mm.

[0067] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, and the gas-liquid volume flow ratio was 600:1, the desulfurization rate was 90.2%.

[0068] Example 10

[0069] The same microchannel device as in Example 8 was used, wherein the depth of the fluid mixing channel was 1 mm.

[0070] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, and the gas-liquid volume flow ratio was 600:1, the desulfurization rate was 84.5%.

[0071] Embodiment 11

[0072] The same microchannel device as in Example 8 was used, wherein the length of the fluid mixing channel was 100 mm.

[0073] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, and the gas-liquid volume flow ratio was 600:1, the desulfurization rate was 82.3%.

[0074] Example 12

[0075] The same microchannel device as in Example 8 was used, wherein the length of the fluid mixing channel was 80 mm.

[0076] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, and the gas-liquid volume flow ratio was 600:1, the desulfurization rate was 81.2%.

[0077] Embodiment 13

[0078] The same microchannel device as in Example 8 was used, wherein the fluid mixing channel width was 3 mm.

[0079] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, and the gas-liquid volume flow ratio was 600:1, the desulfurization rate was 72.3%.

[0080] Embodiment 14

[0081] The same microchannel device as in Example 8 was used, wherein the depth of the fluid mixing channel was 0.1 mm.

[0082] The experiment used a gas containing 3% H2S, the lean amine liquid was a 40wt.% MDEA aqueous solution, the operating temperature was 50°C, the pressure was 0.3Mpa, and the gas-liquid volume flow ratio was 200:1, the desulfurization rate was 99.5%.

[0083] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. On the basis of the present invention, it is obvious to those skilled in the art that the structural dimensions, shape and number of the fluid mixing channel or the number of gas parallel distribution channels in a single fluid mixing channel are modified and improved. Therefore, the improvements and modifications made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed in the present invention.

Claims

1. A microchannel device for enhancing a gas absorption process, characterized in that: The microchannel device comprises an upper cover plate (1), a reactor plate (2) and a lower cover plate (3) which are connected in sequence; The upper surface and the lower surface of the reactor plate (2) are respectively provided with a plurality of fluid mixing channels (10); The interior of the reactor plate (2) is provided with absorbent parallel distribution channels (7), gas parallel distribution channels (8) and reaction liquid parallel outlet channels (9) in sequence along the flow direction in the fluid mixing channel (10); The reactor plate (2) is also provided with an absorbent inlet channel (4), a gas inlet channel (5) and a reaction liquid outlet channel (6); The absorbent inlet channel (4) is connected to the fluid mixing channel (10) via the absorbent parallel distribution channel (7), the gas inlet channel (5) is connected to the fluid mixing channel (10) via the gas parallel distribution channel (8), and the fluid mixing channel (10) is connected to the reaction liquid outlet channel (6) via the reaction liquid parallel outlet channel (9).

2. The microchannel device according to claim 1, characterized in that The fluid mixing channel (10) has a width of 3 to 5 mm, a length of 60 to 300 mm, and a depth of 0.1 to 2 mm.

3. The microchannel device according to claim 1 or 2, characterized in that: The distance between the absorbent parallel distribution channel (7) and the gas parallel distribution channel (8) along the flow direction in the fluid mixing channel (10) is 30 to 50 mm.

4. The microchannel device according to any one of claims 1 to 3, characterized in that: The number of fluid mixing channels (10) on the upper surface and the lower surface of the reactor plate (2) is independently 2 to 15.

5. The microchannel device according to any one of claims 1 to 4, characterized in that: The number of fluid mixing channels (10) on the upper surface and the lower surface of the reactor plate (2) is the same, and is 2 to 15.

6. The microchannel device according to any one of claims 1 to 5, characterized in that: On the upper surface and the lower surface of the reactor plate (2), the interval between two adjacent fluid mixing channels (10) is 3 to 5 mm.

7. The microchannel device according to any one of claims 1 to 6, characterized in that: The reactor plate (2) comprises 1 to 4 rows, for example 2 to 4 rows, of gas parallel distribution channels (8) arranged along the flow direction in the fluid mixing channel (10).

8. The microchannel device according to claim 7, characterized in that: The interval between two adjacent rows of gas parallel distribution channels (8) is 2 to 5 mm.

9. The microchannel device according to any one of claims 1 to 8, characterized in that: The diameter of the absorbent parallel distribution channel (7) is 3 to 5 mm, and / or the diameter of the reaction liquid parallel outlet channel (9) is 3 to 5 mm, and / or the diameter of the gas parallel distribution channel (8) is 1 to 3 mm.

10. The microchannel device according to any one of claims 1 to 9, characterized in that: The absorbent inlet channel (4) and the gas inlet channel (5) are arranged on the same side of the reactor plate (2) and are located on the central axis in the thickness direction; the reaction liquid outlet channel (6) is arranged on the other side of the reactor plate (2) opposite to the absorbent inlet channel (4) and is located on the central axis in the thickness direction.

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