Porous medium spiral microchannel carbon dioxide adsorbent carrier

Abstract

The invention relates to the technical field of carbon dioxide capture, in particular to a porous medium spiral microchannel carbon dioxide adsorbent carrier. Comprising a carrier body; the carrier body is of a honeycomb structure, a plurality of airflow micro-channels spirally extending in the axial direction are formed in the carrier body, the screw pitch of each airflow micro-channel is 5-7 cm, and the aperture of each airflow micro-channel is 5-10 mm; a carbon dioxide adsorbent is loaded in the carrier body. The porous characteristic of the carbon dioxide adsorbent carrier can increase the contact area of the adsorbent and gas, and the carbon dioxide adsorption efficiency is improved. And the spiral structure can prolong the gas flow path and strengthen the rotational flow effect, so that the adsorbent is more fully contacted with the gas, and meanwhile, the design of the spiral channel is beneficial to uniform transfer of heat and improvement of the desorption efficiency.

Description

A porous media spiral microchannel carbon dioxide adsorbent carrier Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and more particularly to a porous media spiral microchannel carbon dioxide adsorbent carrier. Background Technology

[0002] In recent years, with the continuous advancement of the "dual carbon" strategy and the iterative upgrading of the CCUS technology system, the field of direct carbon capture (DAC) of industrial flue gas and air is developing towards higher efficiency, lower energy consumption, and integration. For example, cyclone-enhanced adsorption technology is an advanced gas-solid mass transfer enhancement technology. Relying on the cyclone flow field, it achieves efficient contact between the airflow and the adsorbent, providing a feasible path to break through the efficiency bottleneck of traditional carbon capture technology and reduce operating energy consumption.

[0003] In the swirling enhanced carbon capture system, CO2-containing flue gas forms an ordered swirling field through the air inlet device. Under the combined action of centrifugal force and axial thrust, the airflow fully contacts the adsorbent carrier to complete adsorption and mass transfer. Compared with traditional physical fixed adsorption devices, this technology can significantly increase the gas-solid contact area and shorten the adsorption response time within the same equipment volume.

[0004] However, the application of swirling flow fields also brings technical challenges such as poor adaptability of adsorbent carriers and low adsorption rates. Firstly, conventional adsorbent carriers cannot match the flow trajectory of swirling flow, causing CO2 molecules to remain in the carrier for shorter periods as the gas flow rate increases. Preliminary calculations show that when the gas velocity increases from 0.3 m / min to 1.5 m / min, the CO2 adsorption capacity decreases by 24%, making efficient carbon capture difficult. Secondly, traditional carriers are mostly in a particle-packed or solid block state, resulting in blocked mass transfer channels. Under the centrifugal force of swirling flow, localized accumulation and airflow blockage are easily caused, and even adsorbent wear and decreased cycle stability may occur.

[0005] Faced with the demands for enhanced mass transfer in swirling flow fields characterized by high turbulence, large flow rates, and compact equipment space, conventional particulate adsorption carriers are clearly insufficient to meet the requirements for efficient and low-consumption carbon capture. Currently, the main adsorption carriers suitable for swirling flow fields include honeycomb block carriers, fiber composite carriers, and random porous particulate carriers. Among these, honeycomb block porous microchannel structures, due to their large specific surface area, ordered mass transfer channels, strong airflow guidance, and good mechanical stability, can precisely match the airflow characteristics of swirling flow fields and are considered an effective solution for swirling-enhanced carbon capture in CCUS systems.

[0006] However, existing porous microchannel carriers, due to their disordered channel arrangement and structural design, are still unable to adapt well to the three-dimensional airflow trajectory of the swirling flow field. The diffusion resistance of CO2 molecules is large, and some microchannels are prone to incomplete desorption after adsorption saturation.

[0007] Therefore, in order to address the core shortcomings of existing adsorbents, such as poor carrier compatibility, low mass transfer efficiency, and insufficient cycle stability. Summary of the Invention

[0008] The purpose of this invention is to provide a porous medium spiral microchannel carbon dioxide adsorbent carrier, which solves the technical problems of poor adaptability, low mass transfer efficiency and insufficient cycle stability of existing adsorbent carriers in swirling flow fields.

[0009] To solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a porous medium spiral microchannel carbon dioxide adsorbent carrier, including a carrier body; the carrier body has a honeycomb structure, and multiple airflow microchannels extending spirally along the axial direction are arranged inside it. The pitch of the airflow microchannels is 5-7 cm, and the pore size is 5-10 mm, preferably 10 mm; the carrier body carries carbon dioxide adsorbent.

[0010] In this embodiment, the carrier body is made of mesoporous silica with a specific surface area of ​​not less than 1000 m². 2 / g, porosity not less than 80%.

[0011] In a further embodiment, the outer wall of the carrier body is a metal foam outer wall.

[0012] In a further embodiment, the material of the outer wall of the metal foam is nickel foam with a porosity of 0.85 to 0.95; preferably 0.9.

[0013] In this embodiment, the number of airflow microchannels is 3 to 8, with 5 being the preferred number.

[0014] In this embodiment, the diameter of the carrier body is 60-100 mm.

[0015] In a further embodiment, the carrier body is formed by 3D printing using mesoporous silica as raw material, according to a preset spiral microchannel structure, and then dried and sintered.

[0016] Furthermore, this embodiment is applied in a carbon dioxide capture device, which includes a shell and a swirl plate disposed at the inlet of the shell; the swirl plate is used to form a tangential swirl of CO2-containing gas; and the carrier body is disposed downstream of the swirl plate.

[0017] Furthermore, in this embodiment, the blade angle of the swirl plate is 30° to 60°, with 45° being the preferred angle.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1) The mass transfer efficiency is significantly improved: by setting an axial spiral microchannel, the airflow flows along the spiral path, accurately matching the three-dimensional airflow trajectory of the swirling flow field, which prolongs the contact path and residence time between CO2 molecules and adsorbent. In the range of gas flow rate of 0.3 to 1.5 m / min, the CO2 adsorption capacity is increased by 28% to 38% compared with the traditional disordered porous carrier, and the pressure drop is reduced by more than 15%.

[0019] 2) Enhanced cycle stability: The porous metal foam outer wall ensures structural strength and provides a uniform gas distribution channel, avoiding the wear and pulverization problems common to particle accumulation carriers. After 100 adsorption-desorption cycles, the adsorption capacity decay rate is less than 5%.

[0020] 3) Strong adaptability: The synergistic design of the spiral microchannel and the tangential air inlet of the swirl plate enables the carrier to efficiently adapt to the swirling flow field, making it suitable for various carbon capture scenarios such as industrial flue gas treatment and DAC, and meeting the high-efficiency and low-consumption operation requirements of the CCUS technology system. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings. Figure 1 is a schematic diagram of the structure of a porous media spiral microchannel carbon dioxide adsorbent carrier; Figure 2 is a schematic diagram of the structure of a carbon dioxide capture device.

[0022] In the figure: 1-Airflow microchannel; 2-Outer wall of metal foam; 3-Swirl plate; 4-Carrier body. Detailed Implementation

[0023] Example 1 This example provides a porous media spiral microchannel carbon dioxide adsorbent carrier, the structure of which is shown in Figure 1.

[0024] The carrier body 4 is a cylindrical honeycomb structure, formed using mesoporous silica (SBA-15) as the raw material through 3D printing technology. The specific preparation process is as follows: mesoporous silica powder is mixed with photosensitive resin and dispersant to prepare a ceramic slurry with a solid content of 45wt%. This slurry is then printed using a digital light processing (DLP) 3D printer according to a pre-set spiral microchannel structure, with a layer thickness of 50 μm. After debinding (heating to 600℃ at 1℃ / min and holding for 2 h) and sintering (heating to 800℃ at 5℃ / min and holding for 3 h), the carrier body is obtained.

[0025] The specific surface area of ​​the carrier body was tested to be 1200 m². 2 / g, with a porosity of 85% and a pore size distribution concentrated in 4-6nm. The carrier body has 5 airflow microchannels (1) with a diameter of 10 mm and a pitch of 50 mm. The microchannels extend in a spiral shape along the carrier axis, with a circular cross-section and a right-hand spiral direction.

[0026] The outer wall of the carrier body 4 is a metal foam outer wall 2, prepared by electrochemical deposition: the above-mentioned mesoporous silica carrier is immersed in a nickel electroplating solution at 1.5 A / dm 2 The current density was deposited for 30 min, followed by heat treatment at 450 °C for 1 h in a hydrogen atmosphere to obtain a nickel foam outer wall with a porosity of 0.90 and a wall thickness D of 2 mm. The entire carrier has a diameter of 80 mm and a length of 100 mm.

[0027] The above-mentioned carrier was immersed in an ethanol solution of polyethyleneimine (PEI, molecular weight 800) at a solid-liquid ratio of 1:4 for 24 h. After immersion, it was removed and vacuum dried at 80 °C for 12 h to obtain a composite carrier loaded with carbon dioxide adsorbent. Thermogravimetric analysis showed that the PEI loading was 56 wt%.

[0028] In this embodiment, the high specific surface area (>1000 m²) of mesoporous silica 2 The spiral microchannel structure provides ample loading space for the adsorbent, and a porosity of no less than 80% ensures unobstructed gas diffusion channels. The spiral microchannel structure extends the airflow path, creating a swirling effect within the channel for more thorough contact with the adsorbent. Simultaneously, the spiral structure facilitates uniform heat transfer in both the axial and radial directions, improving desorption and regeneration efficiency. The high thermal conductivity of the metal foam outer wall further enhances the overall thermal conductivity of the carrier, reducing desorption energy consumption; its high porosity (0.85-0.95) also ensures gas exchange capacity between the carrier and the external environment.

[0029] Example 2: This example provides a porous media spiral microchannel carbon dioxide adsorbent carrier, which differs from Example 1 in that the diameter of the airflow microchannel 1 is 5 mm, the pitch is 50 mm, and the number of channels is 5. The remaining structure, materials, and preparation process are the same as in Example 1.

[0030] Example 3: This example provides a porous media spiral microchannel carbon dioxide adsorbent carrier. The difference from Example 1 is that the pitch of the airflow microchannel 1 is 70 mm, the diameter is 10 mm, and the number of channels is 5. The remaining structure, materials, and preparation process are the same as in Example 1.

[0031] Example 4: This example provides a porous media spiral microchannel carbon dioxide adsorbent carrier, which differs from Example 1 in that the diameter of the airflow microchannel 1 is 7 mm, the pitch is 60 mm, and the number of channels is 5. The remaining structure, materials, and preparation process are the same as in Example 1.

[0032] Example 5 This example provides a carbon dioxide capture device, the structure of which is shown in Figure 2.

[0033] A swirl plate 3 is installed at the inlet of the device housing. The blade angle of the swirl plate is 45°, which is used to form a tangential swirl of CO2-containing gas. Downstream of the swirl plate 3, the carrier body 4 described in Example 1 is disposed.

[0034] CO2-containing gas enters the device through the inlet, forms a tangential swirl after passing through the swirl plate 3, and then enters the carrier body 4 along the swirl flow field lines. The gas flows along a spiral path in the airflow microchannel 1, making full contact with the adsorbent on the carrier surface, achieving efficient adsorption and capture of CO2. The swirl plate and the spiral microchannel create a dual swirl effect, further enhancing gas-solid contact mass transfer.

[0035] Comparative Example 1: This comparative example provides a carbon dioxide adsorbent carrier with a conventional structure for performance comparison with the examples.

[0036] The carrier body is a cylindrical solid mesoporous silica block (material is the same as in Example 1, SBA-15), with a diameter of 80 mm and a length of 100 mm. It contains five straight-through microchannels extending axially, each with a pore size of 10 mm, and the channels are parallel to each other. There is no metal foam outer wall structure. PEI is loaded using the exact same impregnation process as in Example 1, with a loading amount of 55 wt%.

[0037] Performance tests were conducted by loading Examples 1-5 and Comparative Example 1 into a carbon dioxide capture device (the structure described in Example 5). The test conditions were as follows: inlet CO2 concentration: 500 ppm (simulated air); inlet air velocity: 1.5 m / min; adsorption temperature: 25℃; relative humidity: 50%; desorption temperature: 100℃ (nitrogen purging).

[0038] Test results analysis: Adsorption capacity: The CO2 adsorption capacity of Examples 1-5 was 7.5-8.2 g / 100g carrier, which is 28%-38% higher than that of Comparative Example 1 (5.6 g / 100g carrier). Among them, Example 4 ( The maximum adsorption capacity of 8.2 g / 100g was achieved with a pore size of 7 mm and a pitch of 60 mm, indicating that a suitable pore size and pitch can achieve an optimized balance between mass transfer resistance and contact time.

[0039] Pressure drop performance: The pressure drop of Examples 1-5 was 72-88 Pa, which was 25.4%-39.0% lower than that of Comparative Example 1 (118 Pa). The spiral microchannel structure effectively reduced airflow resistance, and the porous nature of the outer wall of the nickel foam also provided additional gas diffusion paths.

[0040] Cyclic stability: After 10 cycles, the capacity retention rates of Examples 1-5 were all ≥95%, and the capacity decay rate after 100 cycles was ≤5%; while in Comparative Example 1, the retention rate dropped to 90% after 10 cycles, and the decay rate after 100 cycles exceeded 10%. This indicates that the composite structure of the spiral microchannel and the outer wall of the metal foam significantly inhibited the loss of adsorbent during desorption and regeneration, while enhancing the structural stability of the carrier.

[0041] Synergistic effect of swirl: The adsorption capacity of Example 5 (complete device including swirl plate) is similar to that of Example 1 (same carrier). However, in actual operation, the swirl plate improves the uniformity of gas distribution in the inlet section. Under higher gas velocity conditions (≥1.0 m / min), the adsorption capacity of Example 5 is about 5% higher than that of Example 1, indicating that the swirl plate and the spiral microchannel have a synergistic effect in enhancing mass transfer.

[0042] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A porous media spiral microchannel carbon dioxide adsorbent carrier, characterized in that: It includes a carrier body (4); the carrier body (4) has a honeycomb structure and is provided with multiple airflow microchannels (1) extending spirally along the axial direction inside. The pitch of the airflow microchannels (1) is 5-7cm and the pore size is 5-10mm; the carrier body (4) carries a carbon dioxide adsorbent.

2. The porous media spiral microchannel carbon dioxide adsorbent carrier according to claim 1, characterized in that: The carrier body (4) is made of mesoporous silica with a specific surface area of ​​not less than 1000 m². 2 / g, porosity not less than 80%.

3. The porous media spiral microchannel carbon dioxide adsorbent carrier according to claim 2, characterized in that: The outer wall of the carrier body (4) is a metal foam outer wall (2).

4. The porous media spiral microchannel carbon dioxide adsorbent carrier according to claim 3, characterized in that: The outer wall (2) of the metal foam is made of nickel foam with a porosity of 0.85 to 0.

95.

5. The porous media spiral microchannel carbon dioxide adsorbent carrier according to claim 1, characterized in that: The number of airflow microchannels (1) is 3 to 8.

6. The porous media spiral microchannel carbon dioxide adsorbent carrier according to claim 1, characterized in that: The diameter of the carrier body (4) is 60-100 mm.

7. The porous media spiral microchannel carbon dioxide adsorbent carrier according to any one of claims 1-6, characterized in that: The carrier body (4) is formed by 3D printing technology using mesoporous silica as raw material, according to a preset spiral microchannel structure, and then dried and sintered.

8. The porous media spiral microchannel carbon dioxide adsorbent carrier according to any one of claims 1-6, characterized in that: It is used in a carbon dioxide capture device, which includes a shell and a swirl plate (3) disposed at the inlet of the shell; the swirl plate (3) is used to make CO2-containing gas form a tangential swirl; the carrier body (4) is disposed downstream of the swirl plate (3).

9. The porous media spiral microchannel carbon dioxide adsorbent carrier according to claim 8, characterized in that: The blade angle of the swirl plate is 30° to 60°.

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