CN102784543B - A Fractal Microchannel Reactor System and Method for Enhancing CO2 Absorption - Google Patents

Abstract

The present invention provides a fractal microchannel reactor system and method for enhanced _CO2 absorption. The method adopts a fractal microchannel reactor system, so that the CO2 _- containing gas material and the absorption liquid are uniformly distributed through the fractal microchannel distribution plate respectively, and then are placed on the fractal microchannel collector plate at 0.1~8.0MPa, 10~100℃ , Rapid mixing and absorption in 0.001~100 seconds. The system is composed of an upper cover plate, a lower cover plate, and a mixed absorption unit and a heat exchange unit stacked between the upper cover plate and the lower cover plate. The mixed absorption unit and the heat exchange unit are alternately stacked and matched. The invention can perform in-situ heat exchange and absorption within milliseconds to microseconds, is a micro-reaction technology that can realize rapid amplification, and provides an efficient absorption technology for separation and decarbonization in coal chemical, natural gas, petrochemical and other fields.

Description

A Fractal Microchannel Reactor System and Method for Enhancing CO2 Absorption

technical field

The invention relates to a fractal microchannel reactor system capable of realizing _CO2 high-efficiency absorption, in particular to a microchannel reactor technology capable of strengthening _CO2 absorption. The invention provides a high-efficiency absorbing microchannel reactor technology for decarbonization and carbon capture in the fields of flue gas, synthetic ammonia, oilfield associated gas, natural gas, petrochemical industry, natural gas chemical industry, coal chemical industry and the like.

Background technique

At present, the global annual CO ₂ emissions due to the burning of fossil fuels are as high as 20 billion tons, and the total CO ₂ produced by the combustion of fossil energy accounts for about 82% of the total gas. The greenhouse effect caused by the massive emission of CO ₂ has made the earth's climate environment increasingly worse. The convening of the "Copenhagen Climate Conference" indicates that the reduction of CO ₂ emissions has reached an urgent level. At present, the world's main energy is still fossil energy, and no clean energy that can be completely replaced has been found. Therefore, reducing CO ₂ emissions is the main task at this stage. According to statistics, China's total greenhouse gas (mainly CO ₂ ) emission ranks second in the world. With the rapid development of the national economy, it is likely to rank first in the world in more than ten years. Therefore, greenhouse gas capture must be carried out as soon as possible. Collection, storage and resource utilization technologies to reduce greenhouse gas emissions.

_CO2 capture technology mainly consists of: chemical absorption, physical absorption, pressure swing adsorption, membrane separation, etc. Compared with other technologies, the chemical absorption technology with MDEA as the main solvent is currently dominant. _CO2 capture devices generally use packed towers as absorption towers. Although various new packings emerge in endlessly, packed towers are prone to liquid flooding and fog The disadvantages of entrainment, tower corrosion and low processing capacity of tower equipment per unit volume are still difficult to eradicate, and the absorption efficiency is low.

Microchannel reactors generally refer to reactors with a reaction channel width of less than 1 mm. Compared with traditional reactors, microchannel reactors have the advantages of good heat and mass transfer performance, continuous process, and good safety. In the early 1990s, researchers began to try to apply microreactors to chemical reactions. In just a dozen years, this technology has come a long way around the world. Patent CN 101612510A discloses a microchannel absorber for absorbing _CO2 , which replaces the filler on the conventional absorption tower with a regular microchannel similar to honeycomb, which improves the processing capacity of the equipment. US Patent US 20100024645 relates to a method of using ionic liquids as absorbents to separate gases in microchannels, and a way to improve thermal efficiency—using the heat of absorption reaction for the desorption process to reduce additional energy. US 20060073080 discusses multiphase mixing in a microchannel mixer, and the two phases are dispersed in the microchannel through the holes on the microchannel to obtain a higher gas-liquid phase contact area. Patent CN 101116798A discloses a fractal channel mixer based on the principle of impinging flow, so that two or more fluids can be divided and refined through the bifurcated fluid channels on the guide plate, and then sprayed out from the through holes on the isolation plate , forming opposing impinging flows colliding with each other and mixing.

In the microchannel reactors involved in the above-mentioned patents, the regular microchannel absorber uses spray dispersion to realize the mixing of gas-liquid two-phase fluids. Although it is more efficient than conventional tower reactors, it cannot guarantee the gas-liquid flow in each channel. The ratio of the two phases is even and consistent, resulting in a decrease in absorption efficiency. From the disclosed content, this kind of regular microchannel will become the main constraint factor for its large-scale application in terms of material selection and preparation, that is, it is difficult to meet the requirements of large-scale production. Require. Moreover, the layer-by-layer stacking of micro-heat exchangers and micro-absorbers cannot be highly integrated, and it is difficult to achieve in-situ efficient heat exchange in the absorption or desorption process. The patent US 20100024645 emphasizes the energy utilization of the microchannel separation system, and US 20060073080 only strengthens the mixing from the size of the hole or the length of the hole extension, and also involves the heat exchange with the microchannel heat sink, but for this kind of pore distribution and microchannel The study of structural synergistically enhanced mass transfer has not involved, or at least has not disclosed, the geometrical characteristics of microreactors for synergistically enhanced mass transfer. For a mixing unit, the mixing effect of the fractal channel mixer disclosed in the patent CN 101116798A is better, but for the multi-chip superimposed parallel amplification process, there will be disadvantages such as uneven fluid distribution and heat exchangers that cannot be stacked and integrated. It is difficult to realize multi-chip stacking and parallel amplification.

Contents of the invention

The purpose of the present invention is to address the deficiencies of the prior art, by improving the structure of the fractal microchannel to make the gas-liquid two-phase material evenly distributed, to strengthen the mixing effect and heat transfer performance of the gas-liquid two-phase material in the fractal microchannel, and to provide an enhanced CO _2. A method and system for high-efficiency absorption to improve absorption efficiency and reduce system energy consumption.

To achieve the above object, the technical solution adopted in the present invention is:

A fractal microchannel reactor system for strengthening _CO2 absorption, said fractal microchannel reactor system consists of an upper cover plate, a lower cover plate, and one or more than two mixed absorption channels between the upper cover plate and the lower cover plate Unit, one or more than two heat exchange units stacked layer by layer, mixed absorption unit and heat exchange unit stacked alternately, matching combination; each mixed absorption unit includes a gas material fractal microchannel distribution plate containing CO ₂ stacked in sequence or A fractal microchannel distribution plate for absorption liquid, a fractal microchannel distribution plate for absorption liquid or a fractal microchannel distribution plate for gas material containing CO ₂ , and a fractal microchannel collector plate; each heat exchange unit is composed of at least one parallel The multi-channel micro-heat exchange plate consists of micro-channels.

The fractal microchannel on the gas material fractal microchannel distribution plate containing _CO refers to that one side surface of the distribution plate is provided with a fractal microchannel, and the fractal microchannel refers to the channel number from the material inlet to the material outlet by 2 ⁿ The power increases step by step in a geometric progression, n≥1 is a positive integer, and each channel has two identical fractal branch channels distributed in the next level. There is a "T"-shaped structure between the two channels of the first level; the fractal structure of the last level is: the end of the branch channel of the penultimate level extends to the side perpendicular to the axial direction of the branch channel, and there is a penetrating channel at the end of the extension channel. The end hole of the distribution plate body is provided with a through hole penetrating through the distribution plate body on the side corresponding to the axis of the branch channel.

The fractal microchannel on the fractal microchannel distribution plate of the absorbing liquid means that one side of the distribution plate is provided with a fractal microchannel, and the fractal microchannel means that the number of channels from the material inlet to the material outlet is geometrically arranged to the power of ²ⁿ . The number of series increases step by step, and n≥1 is a positive integer. Each channel has two identical fractal branch channels distributed in the next level. Except for the last level channel, one channel of the upper level and two The channel has a "T"-shaped structure; the final fractal structure is: the end of the penultimate branch channel extends to the side perpendicular to the axial direction of the branch channel, and a penetrating distribution plate is provided at the end of the extension channel The end hole at the end of the extension channel is provided with a through hole through the body of the distribution plate on the side corresponding to the axis of the branch channel;

This extension channel is opposite to the direction of the extension channel of the corresponding last-level fractal structure on the gas material fractal microchannel distribution plate containing CO ₂ , and _is a left-right symmetrical structure with the penultimate branch channel; Corresponding to the through-hole of the last-order fractal structure on the material fractal micro-channel distribution plate; this through-hole corresponds to the end hole of the extended channel of the last-level fractal structure corresponding to the _CO2- containing gas material fractal micro-channel distribution plate correspond.

The fractal microchannel on the collector plate of the fractal microchannel refers to that one side surface of the distribution plate is provided with a fractal microchannel, and the fractal microchannel refers to that the number of passages from the material outlet to the material inlet is geometrically graded according to the power of 2 ⁿ The number increases step by step, n≥1 is a positive integer, each channel has two identical fractal branch channels distributed in the next level, and there is a "T"-shaped structure between one channel of the upper level and the two channels of the lower level ;

The end of the last branch channel corresponds to the end holes and through holes of the last fractal structure on the gas material fractal microchannel distribution plate containing _CO2 or the absorption liquid fractal microchannel distribution plate.

Except for the final channel, the fractal microchannel structure on the fractal microchannel distribution plate and the fractal microchannel collector plate is the same, and the positions correspond to each other when superimposed;

The fractal microchannel distribution plate, the fractal microchannel collector plate and the microchannel heat exchanger plate are all provided with two through-holes for the material inlet and two through-holes for the inlet and outlet of the heat exchange medium through the plate body, A material outlet through hole that runs through the plate body, and the positions of the through holes correspond to each other when superimposed.

The size of the fractal microchannel distribution plate and the collector plate is expressed as follows: the equivalent diameter of the through hole and the end hole of the last stage is 500~5000 μm; the width of the last stage microchannel is 50~1000 μm, and the depth 50~1000 μm, length 1000~5000 μm; the bifurcation angle between two branch channels of the same level is 0~180 ^o ; the ratio of the length of each fractal microchannel to the length of the next fractal microchannel is 1.0~1.5 ; The depth of each level of fractal microchannel is equal to the depth of the next level of fractal microchannel; the ratio of the width of each level of fractal microchannel to the width of the next level of fractal microchannel is 1.0-2.5.

The method of the microchannel reactor system for enhanced _CO2 absorption:

After the gas material containing _CO2 and the absorption liquid are evenly distributed through the fractal microchannel distribution plate, they are quickly mixed on the fractal microchannel collector plate under the conditions of 0.1~8.0 MPa, 10~100°C, and 0.001-100 seconds to complete absorb;

The mixed absorption process refers to that the gas material containing _CO2 is distributed uniformly on the gas material fractal microchannel distribution plate containing _CO2 or the absorption liquid is evenly distributed in the fractal microchannel on the absorption liquid fractal microchannel distribution plate. The outflow from the hole at the end of the extended channel of the fractional structure passes through the through hole of the last fractal structure on the corresponding absorbing liquid fractal microchannel distribution plate or the _CO2- containing gas material fractal microchannel distribution plate, and respectively enters the The end of the last branch channel on the corresponding fractal microchannel collector plate completes the first mixing and absorption process in the penultimate branch channel on the fractal microchannel collector plate, and then the mixed material is in the fractal microchannel The second mixing and absorption process is completed in the penultimate third-level branch channel on the collector plate, and so on, all the raw materials from the _fractal microchannel distribution plate of gas After n-1 times of mixing and absorption are completed on the flow plate, they are collected at the outlet through hole on the fractal microchannel collector plate, and finally pass through each fractal microchannel distribution plate, each fractal microchannel collector plate, and each micro heat exchange plate. The fractal microchannel reactor system flows out of the lower cover plate or the upper cover plate after the through hole.

In the enhanced _CO2 absorption system and method provided by the present invention, the heat exchange unit refers to a multi-channel heat exchange unit that can remove the released heat in time during the mixed absorption process of the _CO2 -containing gas material and the absorption liquid Plate (Figure 6 or its derivative structure shown in Figure 6), which is adjacently matched with the fractal microchannel collector plate.

In the enhanced _CO2 absorption system and method provided by the present invention, in the fractal microchannel reactor system, except for the absorption unit and the heat exchange unit at both ends, one or more absorption units are all between the two heat exchange units Between, or, one or more than two heat exchange units are interposed between two absorption units.

In the enhanced _CO2 absorption system and method provided by the present invention, the residence time of the _CO2 -containing gas material to be absorbed and the absorption liquid in the fractal microchannel microreactor system is 0.001-100 seconds, preferably 0.01-100 seconds 1.5 seconds, the pressure of the absorption system is 0.1-8.0 MPa, preferably 1.0-6.0 MPa, and the temperature of the absorption system is 10-100°C, preferably 20-60°C.

_In the enhanced CO ₂ absorption system and method provided by the present invention, the gas material containing CO ₂ may contain CH ₄ , CO, N ₂ , HCl, H ₂ , O ₂ , H ₂ S, NO _x , SO _x , low-carbon alkanes and low-carbon olefins and other gases; the absorption liquid is organic amines or their composite components or organic amines with activators added, or ionic liquid absorbents and their composite components, It is also a composite component of organic amine and ionic liquid, or alkaline absorption liquid such as ammonia solution. The absorption liquid is a technology well known to those skilled in the art, and it is under continuous development and perfection. The purpose of the present invention is to provide a fractal microchannel reactor system and method for strengthening _CO2 absorption. The absorption process in the system can be further strengthened by the method of the present invention.

The _CO2 -containing gas material and absorbing liquid to be absorbed by the present invention are respectively uniformly distributed through the fractal microchannel distribution plate, and then rapidly mixed and absorbed on the fractal microchannel collector plate under optimized pressure, temperature and residence time. The released heat of the process is removed by the multi-channel micro heat exchange unit (Figure 6 or its derivative structure shown).

In view of the above features of the present invention, compared with the prior art, it has the following technical effects:

(1) The reaction rate can be greatly improved, and the absorption time is shortened from tens of minutes to milliseconds while maintaining the same absorption rate.

(2) The volume of the system is reduced by 1 to 2 orders of magnitude, the process is simple, the operation flexibility is large, and it is easy to control. The instantaneous holding amount of the reaction material in the reaction system is small, and the process safety is high, especially for _CO2 absorption under high pressure. Operation The process is safer and more reliable.

(3) In view of the close connection between the heat exchange unit and the absorption unit, the in-situ removal of the absorption heat can be realized, which is conducive to the improvement of the absorption rate, and it is easy to realize the layer-by-layer stacking and high integration of the micro-heat exchanger and the micro-absorber.

(4) The microchannel reactor system has a fractal structure, which can ensure that the gas-liquid two-phase material distribution in each channel is uniform and consistent, and it is easy to realize parallel amplification.

The present invention can strengthen the chemical absorption of _CO2 . For the decarburization process of alkanolamine chemical absorption, the removal rate of high-concentration _CO2 is higher than 90% under the condition that the residence time is only 0.05-0.5 seconds and the reaction pressure is _5MPa . The concentration can be reduced from 32.3% of the inlet to less than 5% of the outlet.

Description of drawings

Figure 1 is a schematic diagram of the internal structure of the gas material fractal microchannel distribution plate (1) containing _CO2 ;

Fig. 2 is the internal structure schematic diagram of the gas material fractal microchannel distribution plate ( ₂ ) containing CO2;

Figure 3 is a schematic diagram of the internal structure of the absorption liquid fractal microchannel distribution plate (1);

Figure 4 is a schematic diagram of the internal structure of the absorption liquid fractal microchannel distribution plate (2);

Fig. 5 is the internal structure schematic diagram of fractal microchannel collector plate;

Figure 6 is a schematic diagram of the internal structure of the multi-channel micro-heat exchange plate;

Figure 7 is an assembly diagram of the fractal microchannel system for _CO2 absorption;

7-1 is the inlet of the gas phase material containing _CO2 ; 7-2 is the inlet of the absorption liquid; 7-3 is the inlet of the heat exchange unit; 7-4 is the outlet of the heat exchange unit; 7-5 is the upper cover plate; fractal microchannel distribution plate for gas material containing _CO2 ; 7-7 are fractal microchannel distribution plates for absorption liquid; 7-8 are fractal microchannel collector plates; Mixed absorption + heat exchange unit; 7-11 is the material outlet after mixed absorption; 7-11 is the lower cover.

Fig. 8 is the reaction result of MDEA-PZ absorbing CO ₂ in the fractal microchannel system of the present invention.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention, but not for limiting the protection scope of the present invention. The present invention is relatively familiar to those skilled in the field of microreactor or microchemical industry: what the present invention relates to is a fractal microchannel absorber, and the characteristic size of the channel is in the order of microns to millimeters; in essence, it relates to gas-liquid in the microchannel Two-phase fluid mixing mass transfer process. The difference is that the present invention provides a new type of microchannel structure, which can make the two-phase fluid evenly and finely distributed, so as to strengthen the mass transfer between the gas-liquid two-phase fluid in the microchannel, especially for the absorption of gas-phase materials containing CO ₂ One of the series of technologies.

A fractal microchannel reactor system and method for strengthening _CO2 absorption, the fractal microchannel reactor system consists of an upper cover plate, a lower cover plate, and one or more than two mixing channels between the upper cover plate and the lower cover plate The absorption unit, one or more than two heat exchange units are stacked layer by layer, the mixed absorption unit and the heat exchange unit are alternately stacked, and the absorption unit and the heat exchange unit are matched and combined; each mixed absorption unit includes a CO ₂ containing A gas material fractal microchannel distribution plate or an absorption liquid fractal microchannel distribution plate, an absorption liquid fractal microchannel distribution plate or a gas material fractal microchannel distribution plate containing CO ₂ , and a fractal microchannel collector plate; each The heat exchange unit consists of at least one multi-channel micro-heat exchange plate containing parallel micro-channels (Fig. 6 or its derivatives as shown).

In the enhanced _CO2 absorption system and method provided by the present invention, the fractal microchannel on the fractal microchannel distribution plate (Figure 1 or Figure 2 or its derivative structure shown) of the _CO2 -containing gas material refers to the distribution plate There is a fractal microchannel on the surface of one side. The fractal microchannel means that the number of channels from the material inlet to the material outlet increases step by step in a geometric progression according to the power of 2 ⁿ (n≥1, positive integer), and each channel in the next There are two identical fractal branch channels distributed in each level, and there is a "T" shape structure between one channel of the upper level and the two channels of the lower level (excluding the last level). The last level fractal structure is: the end of the penultimate branch channel (Fig. 1-104 or Fig. 2-204) extends to the side perpendicular to the axial direction of this branch channel, and in the extension channel (Fig. 1-101 or Fig. 1-101 or Fig. 2-201) There is an end hole through the body of the distribution plate (Figure 1-102 or Figure 2-202) at the end, and the corresponding side of the end hole of the extension channel (Figure 1-102 or Figure 2-202) There is a through hole through the body of the distribution plate (Fig. 1-103 or Fig. 2-203).

In the enhanced _CO2 absorption system and method provided by the present invention, the fractal microchannel on the absorption liquid fractal microchannel distribution plate (Figure 3 or Figure 4 or its derivative structure shown) refers to the distribution plate on one side There are fractal microchannels, which means that the number of channels from the material inlet to the material outlet increases step by step in a geometric progression according to the power of 2 ⁿ (n≥1, positive integer), and each channel is distributed in the next level. Two identical fractal branch channels, one channel on the upper level and two channels on the lower level form a "T"-shaped structure (not including the last level). The final fractal structure is: the end of the penultimate branch channel (Fig. 3-304 or Fig. 4-404) extends to the side perpendicular to the axial direction of the branch channel, and the extension channel (Fig. 3-301 or Fig. 3-301 or Fig. 4-401) at the end is provided with an end hole (Fig. 3-303 or Fig. 4-403) that runs through the body of the distribution plate, where the end of the channel (Fig. 3-301 or Fig. 303 or Figure 4-403) is provided with a through hole through the body of the distribution plate (Figure 3-302 or Figure 4-402); this extension channel (Figure 3-301 or Figure 4-401) is connected to the _2. The extension channel of the last fractal structure corresponding to the gas material fractal microchannel distribution plate (Figure 1-101 or Figure 2-201) is in the opposite direction, and the penultimate branch channel (Figure 1-104 or Figure 2- 204 or Fig. 3-304 or Fig. 4-404) has a left-right symmetrical structure; this end hole (Fig. 3-303 or Fig. 4-403) is in contact with the _CO2 -containing gas material fractal microchannel distribution plate (Fig. 1 or Fig. 2 or The through-hole (Fig. 1-103 or Fig. 2-203) of the corresponding final fractal structure on the derivation structure shown therein corresponds to; this through-hole (Fig. 3-302 or Fig. 4-402) corresponds to _the The gas material fractal microchannel distribution plate (Fig. 1 or Fig. 2 or its derivative structure shown in Fig. 1 or Fig. 2 or its derivative structure) corresponds to the extension channel end hole (Fig. 1-102 or Fig. 2-202) corresponding to the last fractal structure.

In the enhanced _CO2 absorption system and method provided by the present invention, the fractal microchannel on the fractal microchannel collector plate (Fig. 5 or its derivative structure shown in FIG. Channel, fractal microchannel means that the number of channels from the material outlet to the material inlet increases geometrically to the power of ²ⁿ (n≥1, positive integer), and each channel has two identical In the fractal branch channel, there is a "T"-shaped structure between one channel on the upper level and two channels on the lower level. The end of the last branch channel (Fig. 5-501) is connected to the gas material fractal microchannel distribution plate containing CO ₂ (Fig. 1 or 2 or its derivative structure) or the absorption liquid fractal microchannel distribution plate (Fig. 3 or Fig. 4 or its derivative structure shown) on the end hole (Fig. 1-102 or Fig. 2-202 or Fig. 3-303 or Fig. Or Figure 2-203 or Figure 3-302 or Figure 4-402) correspond.

In the enhanced _CO2 absorption system and method provided by the present invention, the fractal microchannel distribution plate (Fig. 1 or Fig. 2 or Fig. 3 or Fig. 4 or its derivative structure shown in Fig. The fractal microchannel structures on the fractal microchannel or its shown derivative structure) are the same (not including the final stage), and the positions correspond to each other when superimposed; the fractal microchannel distribution plate (Fig. 1 or Fig. 2 or Fig. 3 or Fig. 4 or The derivative structure shown in it), the fractal microchannel collector plate (Fig. 5 or its derivative structure shown in it) and the microchannel heat exchanger plate (Fig. The material inlet through hole of the plate body (Figure 1-107 and Figure 1-108 or Figure 2-207 and Figure 2-208 or Figure 3-307 and Figure 3-308 or Figure 4-407 and Figure 4-408 or Figure 5 -505 and Figure 5-506 or Figure 6-603 and Figure 6-604), two heat exchange medium inlet and outlet through holes through the plate body (Figure 1-105 and Figure 1-106 or Figure 2-205 and Figure 2 -206 or Figure 3-305 and Figure 3-306 or Figure 4-405 and Figure 4-406 or Figure 5-503 and Figure 5-504 or Figure 6-601 and Figure 6-602), a material that runs through the plate Outlet through holes (Figure 1-109 or Figure 2-209 or Figure 3-309 or Figure 4-409 or Figure 5-507 or Figure 6-605), the positions of the through holes correspond to each other when superimposed (Figure 1-107, Figure 3 -307, Figure 5-505 and Figure 6-603, Figure 1-108, Figure 3-308, Figure 5-506 and Figure 6-604, Figure 1-105, Figure 3-305, Figure 5-504 and Figure 6 -602, Figure 1-106, Figure 3-306, Figure 5-503, and Figure 6-601, Figure 1-109, Figure 3-309, Figure 5-507, and Figure 6-605; or Figure 2-207, Figure 4-407, Figure 5-505 and Figure 6-603, Figure 2-208, Figure 4-408, Figure 5-506 and Figure 6-604, Figure 2-205, Figure 4-405, Figure 5-504 and Figure 6-602, Figure 2-206, Figure 4-406, Figure 5-503, and Figure 6-601, Figure 2-209, Figure 4-409, Figure 5-507, and Figure 6-605).

In the enhanced _CO2 absorption system and method provided by the present invention, the mixed absorption process refers to the _CO2 -containing gas material in the _CO2 -containing gas material fractal microchannel distribution plate (Fig. 1 or Fig. 2 or its derivative shown in Fig. structure) or after the absorption liquid is evenly distributed in the fractal microchannel on the absorption liquid fractal microchannel distribution plate (Fig. 3 or Fig. 4 or its derivative structure shown in Fig. -101 or Figure 2-201 or Figure 3-301 or Figure 4-401) outflow from the end hole (Figure 1-102 or Figure 2-202 or Figure 3-303 or Figure 4-403), through the corresponding Absorption liquid fractal microchannel distribution plate (Figure 3 or Figure 4 or its derivative structure shown) or gas material fractal microchannel distribution plate containing _CO2 (Figure 1 or Figure 2 or its derivative structure shown) The through-holes of the final fractal structure (Fig. 3-302 or Fig. 4-402 or Fig. 1-103 or Fig. 2-203) respectively enter the corresponding fractal microchannel collector plates (Fig. 5 or its derivatives shown in Fig. structure) at the end of the last-level branch channel (Figure 5-502), the first mixing and absorption process is completed in the penultimate second-level branch channel (Figure 5-508) on the fractal microchannel collector plate, and then the mixture The material completes the second mixing and absorption process in the third-to-last branch channel (Fig. 5-509) on the fractal microchannel collector plate, and so on. All the gas materials from the fractal microchannel distribution plate containing _CO2 Figure 2 or its derivative structure shown in Figure 2) and the raw materials of the absorption liquid fractal microchannel distribution plate (Figure 3 or Figure 4 or its derivative structure shown in Figure 3 or Figure 4 or its derivative structure shown in) after n-1 times of mixed absorption on the fractal microchannel collector plate , gather at the outlet through hole (Fig. 5-507) on the fractal microchannel collector plate (Fig. 5 or its derivative structure shown in Fig. 5), and finally pass through each fractal microchannel distribution plate, each fractal microchannel collector plate, The through-holes on each micro-heat exchange plate flow out of the fractal micro-channel reactor system on the lower cover plate or the upper cover plate.

In the enhanced _CO2 absorption system and method provided by the present invention, the size of the fractal microchannel distribution plate and the collector plate is expressed as follows: the equivalent diameter of the through hole and end hole of the last stage is 500 ~ 5000 μm, preferably 500~2000 μm; the width of the final microchannel is 50~1000 μm, preferably 200~800 μm, the depth is 50~1000 μm, preferably 200~500 μm, and the length is 1000~5000 μm, preferably 2000~ 4000 μm; the bifurcation angle between the two branch channels of the same level is 0~ ^180o , preferably 30~ ^180o ; the ratio of the length of each fractal microchannel to the length of the next fractal microchannel is 1.0~1.5, preferably 1.2~1.45; the depth of each level of fractal microchannel is equal to the depth of the next level of fractal microchannel; the ratio of the width of each level of fractal microchannel to the width of the next level of fractal microchannel is 1.0~2.5, preferably 1.5~2.0.

Figure 7 shows an example of the assembly diagram of the fractal microchannel reactor system for enhanced _CO2 absorption, the upper cover plate (Figure 7-705), the lower cover plate (Figure 7-7012), and the upper cover plate and the lower cover plate One or more mixed absorption units (Figure 7-7010) and one or more heat exchange units (Figure 7-709) are stacked between the plates, and the mixed absorption unit (Figure 7-7010) and heat exchange The unit layers (Fig. 7-709) are stacked alternately, and the absorption unit and the heat exchange unit are matched and combined; each mixed absorption unit (Fig. 7-7010) includes a gas material fractal microchannel distribution plate containing CO ₂ stacked in sequence (Fig. 7 -706) or an absorption liquid fractal microchannel distribution plate (Fig. 7-707), an absorption liquid fractal microchannel distribution plate (Fig. 7-707) or a CO ₂ containing gas material fractal microchannel distribution plate (Fig. 7- 706), and a fractal microchannel collector plate (Figure 7-708); each heat exchange unit (Figure 7-709) is composed of at least one multi-channel micro heat exchange plate containing parallel microchannels (Figure 6 or its derived structures shown).

Fig. ₁ and Fig. 2 are containing CO among the present invention two kinds of common patterns of gas material fractal microchannel distribution plate internal structure; Fig. 3 and Fig. 4 are two kinds of common patterns of absorbing liquid fractal microchannel distribution plate internal structure; They are not limited to these two modes in the specific implementation process, and can be changed arbitrarily within the structural parameters described in claims 2 and 3 of the present invention, or other optimization improvements can be made.

Fig. 5 is a common mode of the internal structure of the fractal microchannel collector plate, which is not limited to the mode shown in the specific implementation process, and can be optimized and improved according to any transformation in the structural parameters described in claims 2 and 3 of the present invention; Fig. 6 It is a common mode of the internal structure of the multi-channel micro-heat exchange plate, and the specific implementation process is not limited to the mode shown, and can be optimized and improved according to any transformation within the structural parameters described in claim 1 of the present invention.

The enhanced CO ₂ absorption system and method provided by the present invention are mainly used in: In addition to CO _{2 ,} gas materials may also contain CH ₄ , CO, N ₂ , HCl, H ₂ , O ₂ , H ₂ S, NO _x , SO _x , low-carbon alkanes and low-carbon olefins and other gases; the absorption liquid used can be organic amines or their composite components or organic amines with activators added, or ionic liquid absorbents and their composite components, or organic amines Composite components with ionic liquids, or alkaline absorption liquids such as ammonia solution.

A specific implementation process is as follows: firstly, the gas material containing CO ₂ and the absorption liquid enter the gas material fractal microchannel distribution plate containing CO ₂ (Fig. 1) and the absorption liquid fractal microchannel distribution plate (Fig. 3) respectively in a certain proportion; After the _CO2 gas material is evenly distributed on the gas material fractal microchannel distribution plate (Figure 1) containing _CO2 , it flows out at the end port of the last stage of the extended channel (Figure 1-102), and passes through the absorption liquid fractal microchannel distribution plate (Figure 1). The last-stage through hole (Fig. 3-302) on the channel distribution plate (Fig. 3) enters the end of the last-stage microchannel (Fig. 5-502) of the fractal microchannel collector plate (Fig. 5), and the The liquid fractal microchannel distribution plate (Fig. 3) absorbs the liquid at the end port of the extension channel (Fig. 3-303) in the last stage, and enters the penultimate fractal microchannel (Fig. 5) of the fractal microchannel collector plate (Fig. 5). -508) before contact, and then enter the penultimate fractal microchannel (Figure 5-508) of the fractal microchannel collector plate (Figure 5) to complete the first mixed absorption, before entering the fractal microchannel collector plate (Figure 5 ) of the penultimate fractal microchannel (Figure 5-509) is in contact with another gas-liquid two-phase mixture material that has been mixed and absorbed for the first time, and then enters the penultimate fractal of the fractal microchannel collector plate The microchannel (Fig. 5-509) completes the second mixed absorption, and so on, all the raw materials from the gas material fractal microchannel distribution plate containing _CO2 (Fig. 1) and the absorption liquid fractal microchannel distribution plate (Fig. 3) are in the After being mixed and absorbed on the fractal microchannel collector plate (Figure 5), it finally flows out through the outlet on the fractal microchannel collector plate (Figure 5) (Figure 7-7011).

The mechanism of the enhanced two-phase fluid mass transfer in the present invention can be briefly described as follows: After the gas-liquid two-phase material passes through the fractal microchannel distribution plate, the two-phase material can be evenly divided and refined by using its symmetrical final fractal structure outlet, Through the bending, folding, rearranging, stretching and other functions of the fractal microchannel collector plate, the two-phase materials are finally formed into a mixed form of alternate arrangement, which greatly shortens the mass transfer distance, strengthens the mixing effect, and improves the _{CO2 concentration} . absorption efficiency.

The gas material fractal microchannel distribution plate containing _CO2 adopts the structure shown in Figure 1, the absorption liquid fractal microchannel distribution plate adopts the structure shown in Figure 3, the fractal microchannel collector plate adopts the structure shown in Figure 5, and the multi-channel heat exchange plate Adopt the structure shown in Figure 6, and assemble as shown in Figure 7 to form a fractal microchannel system containing two mixing absorption units and two heat exchange units. Its dimensions are: the width of the last-stage extension channel is 500 μm, the depth is 250 μm, the length is 3000 μm, the bifurcation angle between the two branch channels of the same level is 180 ^o , the ratio of the length of the upper-level channel to the lower-level channel is 1.4, and the width ratio is 2.0. Finally, it is assembled as shown in Figure 7 into a _CO2 absorption fractal microchannel absorber composed of an upper cover plate, an absorption unit, a heat exchange unit and a lower cover plate. The absorbent uses a mixed absorbent of MDEA (N-methyldiethanolamine)-PZ (piperazine) to chemically absorb CO ₂ in the gas mixture, at MDEA/CO ₂ =2.26 (molar ratio), and the residence time is 0.05~ 0.5 seconds, reaction pressure is 5.0 MPa, temperature is under the condition of 25 ℃, test the mass transfer enhanced absorption effect of the present invention, the reaction result is shown in Fig. 8, in the gas raw material involved in the reaction data in the figure _The volume fraction of CO is 32.3%.

Claims (7)

1. a kind of strengthened _CO The fractal microchannel reactor system that absorbs is characterized in that: described fractal microchannel reactor system is by upper cover plate, lower cover plate, and between upper cover plate, lower cover plate Or two or more mixed absorption units, one or more than two heat exchange units stacked layer by layer, mixed absorption units and heat exchange units stacked alternately, matching combination; each mixed absorption unit includes a _CO2- containing gas material stacked in sequence A fractal microchannel distribution plate or an absorption liquid fractal microchannel distribution plate, an absorption liquid fractal microchannel distribution plate or a _CO2- containing gas material fractal microchannel distribution plate, and a fractal microchannel collector plate; each heat exchange The unit consists of at least one multi-channel micro-heat exchange plate containing parallel micro-channels; The fractal microchannel on the gas material fractal microchannel distribution plate containing _CO refers to that one side surface of the distribution plate is provided with a fractal microchannel, and the fractal microchannel refers to the channel number from the material inlet to the material outlet by 2 ⁿ The power increases step by step in a geometric progression, n≥1 is a positive integer, and each channel has two identical fractal branch channels distributed in the next level. There is a "T"-shaped structure between the two channels of the first level; the fractal structure of the last level is: the end of the branch channel of the penultimate level extends to the side perpendicular to the axial direction of the branch channel, and there is a penetrating channel at the end of the extension channel. The end hole of the distribution plate body is provided with a through hole penetrating through the distribution plate body on the end hole of the extension channel and on the side corresponding to the axis of the branch channel; The fractal microchannel on the fractal microchannel distribution plate of the absorbing liquid means that one side of the distribution plate is provided with a fractal microchannel, and the fractal microchannel means that the number of channels from the material inlet to the material outlet is geometrically arranged to the power of ²ⁿ . The number of series increases step by step, and n≥1 is a positive integer. Each channel has two identical fractal branch channels distributed in the next level. Except for the last level channel, one channel of the upper level and two The channel has a "T"-shaped structure; the final fractal structure is: the end of the penultimate branch channel extends to the side perpendicular to the axial direction of the branch channel, and a penetrating distribution plate is provided at the end of the extension channel The end hole at the end of the extension channel is provided with a through hole through the distribution plate body on the side corresponding to the axis of the branch channel; this extension channel corresponds to the gas material fractal microchannel distribution plate containing _CO2 The direction of the extension channel of the final fractal structure is opposite, and the penultimate branch channel is a left-right symmetrical structure; this end hole corresponds to the through hole of the final fractal structure on the gas material fractal microchannel distribution plate containing CO ₂ Corresponding; this through hole is corresponding to the end hole of the extension channel of the corresponding final stage fractal structure on the gas material fractal microchannel distribution plate containing _CO2 ; The fractal microchannel on the collector plate of the fractal microchannel refers to that one side surface of the distribution plate is provided with a fractal microchannel, and the fractal microchannel refers to that the number of passages from the material outlet to the material inlet is geometrically graded according to the power of 2 ⁿ The number increases step by step, n≥1 is a positive integer, each channel has two identical fractal branch channels distributed in the next level, and there is a "T"-shaped structure between one channel of the upper level and the two channels of the lower level The end of the last branch channel corresponds to the end hole and through hole of the last fractal structure on the gas material fractal microchannel distribution plate containing _CO2 or the absorption liquid fractal microchannel distribution plate. 2. according to the described microchannel reactor system of claim 1, it is characterized in that: except last level passage, the fractal microchannel structure on described fractal microchannel distribution plate and fractal microchannel collector plate is identical, and superposition corresponding to each other; The fractal microchannel distribution plate, the fractal microchannel collector plate and the microchannel heat exchanger plate are all provided with two through-holes for the material inlet and two through-holes for the inlet and outlet of the heat exchange medium through the plate body, A material outlet through hole that runs through the plate body, and the positions of the through holes correspond to each other when superimposed. 3. according to the described microchannel reactor system of claim 1, it is characterized in that: the size of described fractal microchannel distribution plate and collector plate, expression is as follows: the through hole of last level and end hole equivalent diameter are 500 ~5000μm; the last level of microchannels has a width of 50～1000μm, a depth of 50～1000μm, and a length of 1000～5000μm; the bifurcation angle between two branch channels of the same level is 0～180°; each level of fractal microchannels The ratio of the length to the length of the next level of fractal microchannel is 1.0 to 1.5; the depth of each level of fractal microchannel is equal to the depth of the next level of fractal microchannel; the ratio of the width of each level of fractal microchannel to the width of the next level of fractal microchannel 1.0 to 2.5. 4. according to the described microchannel reactor system of claim 1, it is characterized in that: described heat exchanging unit refers to in the process of mixing and absorbing gas material containing _CO2 and absorbing liquid, can release the heat in time The removed multi-channel heat exchange plate, which is adjacent to the fractal microchannel collector plate; In the fractal microchannel reactor system, except for the absorption unit and the heat exchange unit at both ends, one or more absorption units are between the two heat exchange units, or, one or more heat exchange units are between two absorption units. 5. a kind of microchannel reactor system described in claim 1 is used for strengthening CO _The method for absorbing, it is characterized in that: After the _CO2 -containing gas material and the absorption liquid are uniformly distributed through the fractal microchannel distribution plate, they are quickly mixed on the fractal microchannel collector plate under the conditions of 0.1-8.0MPa, 10-100°C, and 0.001-100 seconds to complete absorb; The mixed absorption process refers to that the gas material containing _CO2 is distributed uniformly on the gas material fractal microchannel distribution plate containing _CO2 or the absorption liquid is evenly distributed in the fractal microchannel on the absorption liquid fractal microchannel distribution plate. The outflow from the hole at the end of the extended channel of the fractional structure passes through the through hole of the last fractal structure on the corresponding absorbing liquid fractal microchannel distribution plate or the _CO2- containing gas material fractal microchannel distribution plate, and respectively enters the The end of the last branch channel on the corresponding fractal microchannel collector plate completes the first mixing and absorption process in the penultimate branch channel on the fractal microchannel collector plate, and then the mixed material is in the fractal microchannel The second mixing and absorption process is completed in the penultimate third-level branch channel on the collector plate, and so on, all the raw materials from the _fractal microchannel distribution plate of gas After n-1 times of mixing and absorption are completed on the flow plate, they are collected at the outlet through hole on the fractal microchannel collector plate, and finally pass through each fractal microchannel distribution plate, each fractal microchannel collector plate, and each micro heat exchange plate. The fractal microchannel reactor system flows out of the lower cover plate or the upper cover plate after the through hole. 6. according to the described method of claim 5, it is characterized in that: the gaseous material that contains _CO to be absorbed and the residence time of absorption liquid in the fractal microchannel microreactor system are 0.01～1.5 seconds, and the absorption system pressure is 1.0 ～6.0MPa, the temperature of the absorption system is 20～60℃. _7. The method according to claim 5 or 6, characterized in that the gaseous material containing CO ₂ contains CH ₄ , CO, N ₂ , HCl, H ₂ , O ₂ , H One or more of ₂ S, NO _x , SO _x , low-carbon alkanes and low-carbon olefins; the absorption liquid is organic amines or their composite components or organic amines with activators added, or Ionic liquid absorbent and its composite components, or composite components of organic amine and ionic liquid, or ammonia solution.