Metal organic framework material mediated industrial waste gas carbon dioxide temperature swing adsorption trapping method

Abstract

The invention discloses a metal organic framework material mediated industrial waste gas carbon dioxide temperature swing adsorption trapping method, and belongs to the technical field of industrial waste gas treatment. In order to solve the problems that an adsorbent is easy to inactivate, the regeneration energy consumption is high and the circulation efficiency is low in the environment that industrial waste gas is high in humidity and contains acidic impurities in the existing carbon capture technology, the method comprises the following steps: adopting a double-layer adsorption bed structure, the lower layer is a hydrophobic metal organic framework adsorbent layer formed by self-assembly of zirconium-based metal clusters and fluorine-containing carboxylic acid ligands; after adsorption is saturated, an industrial waste heat medium with the temperature lower than 60 DEG C is injected, and the temperature of the bed layer is uniformly increased to 110-130 DEG C within 5 minutes for carbon dioxide desorption; and after high-purity gas is collected, cooling to 30-50 DEG C within 3 minutes by using dehumidification pretreatment inert purge gas to finish circulation. The method is mainly applied to efficient capture and resource recovery of carbon dioxide in industrial wet and acid-containing waste gas such as steel and coking.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas treatment technology. More specifically, this invention relates to a method for temperature-swing adsorption and capture of carbon dioxide in industrial waste gas mediated by a metal-organic framework material. Background Technology

[0002] Capturing carbon dioxide (CO2) from industrial waste gases is a crucial step in achieving carbon neutrality, especially in high-emission industries such as steel and coking. However, existing temperature-switching adsorption (TSA) technology faces significant challenges in treating industrial waste gases containing moisture and acidity: 1. Adsorbent failure due to high humidity: The relative humidity (RH) of industrial waste gas often reaches over 70%, causing water molecules to compete with CO2 for adsorption sites, significantly reducing capture efficiency. Zeolite molecular sieves (such as 13X) experience a CO2 adsorption capacity reduction of over 40% when RH > 60%; although metal-organic framework materials (MOFs) have high specific surface areas, most are prone to hydrolysis and collapse upon contact with water (e.g., MIL-101 deactivates after 50 cycles at 60% RH). The root cause is that the dynamic diameter of water molecules (≈2.65Å) is similar to that of CO2 (≈3.3Å), easily clogging micropores; hydrophilic groups on the material surface trigger capillary condensation, damaging the pore structure. Pre-dehumidification to RH < 30% can alleviate the problem, but deep dehumidification equipment accounts for more than 35% of the total system cost, and energy consumption increases by 20%~30%.

[0003] 2. Adsorbent poisoning caused by acidic impurities: The exhaust gas contains SO2 (300 ppm) and NO... x Acidic components, such as those at concentrations of 150 ppm, readily form irreversible sulfates / nitrites with amine adsorbents. For example, after amine-functionalized materials come into contact with 100 ppm SO2, the amine oxidation rate reaches 26%, and the sulfur capacity decreases to 48.7 mg-SO2 / g; in zirconium-based MOFs, metal clusters undergo ligand stripping upon contact with acid, leading to crystal structure collapse. Traditional solutions involve adding a pre-washing tower to remove the acid, but this generates saline wastewater and increases the system pressure drop by 15%–20%.

[0004] 3. High regeneration energy consumption and low cycle efficiency: To completely desorb CO2, zeolite or ordinary MOF requires saturated steam regeneration at 150℃, consuming 2.1 GJ / t-CO2. The main bottlenecks are: the low thermal conductivity of the adsorbent (<0.5 W / m·K), the bed heating rate <1℃ / min, and the time >15min; the cooling stage requires purging with dry inert gas for >10min to prevent low-temperature water vapor condensation. The single cycle time exceeds 60min, limiting the processing capacity, and the waste heat utilization rate is less than 40% (industrial waste heat is mostly below 60℃). Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0006] Another objective of this invention is to provide a temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas mediated by metal-organic framework materials. This method utilizes a dual-layer adsorption bed design (upper layer of amino-functionalized mesoporous alumina / lower layer of hydrophobic zirconium-based MOF) to simultaneously address the poisoning by acidic impurities and failure in high-humidity environments within industrial waste gas. Utilizing low-grade waste heat below 60°C, the bed temperature is uniformly raised to the desorption temperature (110-130°C) within 5 minutes, reducing energy consumption by 63% compared to traditional 150°C steam regeneration. The dehumidified inert purge gas is rapidly cooled to the adsorption temperature (30-50°C) within 3 minutes, reducing the single-cycle time to one-third of traditional processes and doubling the processing capacity.

[0007] To achieve these objectives and other advantages according to the present invention, a method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by a metal-organic framework material is provided, comprising the following steps: 1) Industrial waste gas containing carbon dioxide, water vapor and acidic impurities is passed into an adsorption tower filled with a hydrophobic metal-organic framework adsorbent. The hydrophobic metal-organic framework adsorbent is formed by the self-assembly of zirconium-based metal clusters and fluorinated carboxylic acid ligands. The adsorption tower adopts a double-layer adsorption bed structure, with the upper layer being an acidic gas capture layer and the lower layer being the hydrophobic metal-organic framework adsorbent layer. The acidic gas capture layer is composed of honeycomb ceramics loaded with amine-functionalized mesoporous alumina. 2) When the adsorbent reaches the preset adsorption saturation threshold, stop the flow of waste gas and inject low-grade industrial waste heat medium with a temperature below 60℃ into the adsorption tower so that the adsorption bed is uniformly heated to the desorption temperature range of 110-130℃ within 5 minutes. 3) Maintain the desorption temperature to desorb carbon dioxide and collect high-purity carbon dioxide gas; 4) The adsorption bed is cooled to an adsorption temperature of 30-50℃ within 3 minutes by using inert purge gas that has been pretreated by dehumidification, thus completing a single temperature-switching adsorption cycle.

[0008] Preferably, in step 1), the method for preparing the hydrophobic metal-organic framework adsorbent includes: Preparation of precursor solution: Zirconium tetrachloride and 2,3,5,6-tetrafluoroterephthalic acid were added to N,N-dimethylformamide and sonicated for 10 min until completely dissolved. Glacial acetic acid was added as a modifier to obtain a mixture. Hydrothermal synthesis: The mixture was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 120°C for 24 hours; then naturally cooled to room temperature. Post-treatment activation: The solid white precipitate was collected by centrifugation, washed three times with N,N-dimethylformamide, extracted with methanol by Soxhlet extraction for 24 h, and activated under vacuum at 150℃ for 12 h.

[0009] Preferably, the specific preparation method of the acid gas trapping layer includes: Pretreatment of honeycomb ceramic substrate: Cordierite honeycomb ceramic is selected, treated in air atmosphere at 600℃ for 3h to remove organic impurities, immersed in 10% nitric acid solution and ultrasonically vibrated for 30min, rinsed with deionized water until neutral, and dried at 120℃ for later use. Preparation of γ-alumina coating: Boehmite was dispersed in nitric acid aqueous solution, and carboxymethyl cellulose was added as a binder. The mixture was ball-milled for 24 h to form a stable suspension. The suspension was then placed in a vacuum chamber and evacuated to a negative pressure of 0.01 bar. The coating solution was injected and maintained for 20 min. The suspension was then air-dried at room temperature for 12 h, cured at 80 °C for 6 h, and calcined at 550 °C for 4 h to form a γ-Al2O3 crystalline phase layer. The dip-coating-calcination process was repeated 3 times to obtain a uniform coating of 150 micrometers. Amine functionalization loading: Prepare a 30 wt% diethylenetriamine ethanol solution, immerse the coating in it, and gently shake at 60℃ for 6 h; transfer to a vacuum reactor, maintain a negative pressure of 0.1 bar for 40 min, drain the residual liquid, and place in a nitrogen atmosphere for stepwise temperature increase curing: nitrogen flow rate is 5 m / s. 3 At a flow rate of 8 m / h, the temperature is raised to 80℃ within 1 hour, with a nitrogen flow rate of 8 m / h. 3 At a flow rate of 10 m / h, the temperature is increased to 100℃ within 1 hour, and the nitrogen flow rate is 10 m / h. 3 At a temperature of / h, the temperature is increased to 120℃ within 2 hours, forming a chemically bonded amine layer.

[0010] Preferably, in the precursor solution preparation step, before adding glacial acetic acid, after sonicating for 10 min until completely dissolved, the method further includes adding 0.8-1.2% (molar amount) of zirconium tetrachloride in polyethylene glycol diacrylate and continuing sonication for 10 min.

[0011] Preferably, after adding 0.8-1.2% zirconium tetrachloride in the molar amount of polyethylene glycol diacrylate, the method further includes adding 1%-3% by mass of mesoporous titanium dioxide nanoparticles, wherein the particle size of the mesoporous titanium dioxide nanoparticles is 10-20 nm.

[0012] Preferably, in step 1), the hydrophobic metal-organic framework adsorbent layer contains uniformly distributed hydrophobic thermally conductive fin components. These components are made of polytetrafluoroethylene and expanded graphite composites, and the fin surfaces are modified with perfluorooctyltriethoxysilane, satisfying the following conditions: The fin height is 20%-30% of the thickness of the hydrophobic metal-organic framework adsorbent layer; The spacing between adjacent fins is 8-12 mm; Fin tilt angle 20-30 degrees.

[0013] Preferably, the outer wall of the adsorption tower is covered with a phase change temperature control interlayer, which is composed of microencapsulated tetradecane and expanded graphite, with a phase change temperature of 115°C, and satisfies the following: The thickness of the phase change temperature control jacket is 3%-5% of the adsorption tower diameter; Microcapsule particle size 10-50 μm; Graphite accounts for 30%-40% of the total mass.

[0014] Preferably, the exhaust gas inlet and carbon dioxide outlet pipes of the adsorption tower are equipped with three-way plug valves. The rotor flow channel of the three-way plug valve has a 120-degree Y-shaped structure, and the rotation phase of the valve core is linked to the adsorption saturation signal to ensure: The rotor switching action is completed within 0.2 seconds; The overlap angle between the old and new tower flow channels is less than 5 degrees; The inner wall of the three-way plug valve is coated with polytetrafluoroethylene propylene.

[0015] Preferably, the step further includes the following step after the amino-functionalized loading step: A nitrogen-hydrogen mixture with a dew point below -40°C is introduced into the chemically bonded amine layer in the reverse direction. The hydrogen accounts for 5% of the volume, the temperature is maintained at 80°C, the flow rate is 0.5 m / s, and the process is continued for 10 min. Then, the process is switched to the waste gas adsorption process.

[0016] Preferably, in step 4), the discharged purge gas undergoes staged treatment via a vortex tube energy separator: A high-pressure gas-driven pneumatic motor with a pressure of 0.7 MPa recovers kinetic energy and is directly coupled to the compressor main shaft; 0.3 MPa low-pressure gas is returned to the dehumidification system to regenerate activated alumina; The cold end temperature of the separator drops to -15°C, which is used to pre-cool the air entering the dehumidifier.

[0017] The present invention has at least the following beneficial effects: 1. The metal-organic framework (MOF)-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of this invention simultaneously solves the problems of acidic impurity poisoning and high humidity environment failure in industrial waste gas through a double-layer adsorption bed design (upper layer of amino-functionalized mesoporous alumina / lower layer of hydrophobic zirconium-based MOF). Utilizing low-grade waste heat below 60°C, the bed is uniformly heated to the desorption temperature (110-130°C) within 5 minutes, reducing energy consumption by 63% compared to traditional 150°C steam regeneration. Dehumidified inert purge gas is rapidly cooled to the adsorption temperature (30-50°C) within 3 minutes, reducing the single-cycle time to 1 / 3 of the traditional process and doubling the treatment capacity. Actual measurements in a steel plant with 70% RH and 300ppm SO2 waste gas show a CO2 capture efficiency of 98.5% and an adsorbent lifespan exceeding 18 months, resulting in annual energy savings of 27,000 GJ / 10,000 tons of CO2.

[0018] 2. The metal-organic framework (MOF)-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of the present invention employs a hydrothermal synthesis system of zirconium tetrachloride and perfluoroterephthalic acid modulated with glacial acetic acid, combined with methanol Soxhlet extraction and stepwise vacuum activation processes, which improves the uniformity of MOF crystal size by 60% (SEM statistics) and achieves a BET specific surface area of ​​980 m². 2 / g. Perfluorinated ligands form a molecular-level hydrophobic barrier (contact angle 142°). After 100 cycles in humid heat exhaust gas at 70% RH, the CO2 adsorption capacity retention rate is 97.5%, which is more than 3 times longer than that of ordinary zirconium-based MOFs. The deep activation process thoroughly removes residual solvent from the pores, avoiding the micropore clogging problem caused by traditional 80℃ drying. The bulk density is 0.68 g / cm³. 3 Optimization ensures the stability of industrial fixed bed loading.

[0019] 3. The metal-organic framework material-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of the present invention achieves a 150 μm uniform coating (thickness deviation <8 μm) of γ-alumina on the surface of cordierite honeycomb ceramic through vacuum negative pressure dip coating technology, followed by stepwise nitrogen curing and loading of diethylenetriamine, resulting in an amino group chemical bonding rate of 21.3 wt%. This acidic gas capture layer can withstand a space velocity of 4000 h⁻¹. -1 Under certain conditions, the SO2 removal rate at 300 ppm is >98% (outlet <5 ppm), with a sulfur penetration capacity of 68.2 mg-SO2 / g-adsorbent, which is 40% higher than that of ordinary amine-based coatings. After 500 hours of 10 m / s airflow scouring, the coating showed a peeling rate of <2%, and no cracking after 30 thermal shock cycles. After 8000 hours of continuous operation in Baosteel's sintering flue gas, the desulfurization efficiency was still >92%.

[0020] 4. The metal-organic framework material-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of the present invention uses 1% (molar amount) of zirconium tetrachloride polyethylene glycol diacrylate as a flexible crosslinking agent, whose acrylate groups coordinate with zirconium metal clusters to form a stress buffer network. After 300 temperature-switching adsorption cycles (abrupt changes between 125°C and 45°C), the CO2 adsorption capacity retention rate is 98.3%, and the BET specific surface area increases from the initial 980 m². 2 / g decays to 965 m 2 / g (loss <1.5%), fluorine ligand coverage remained >35% (XPS semi-quantitative analysis), MOF particle breakage rate <5% (control group >28%), and bed pressure drop increased by only 8%. The crosslinking agent occupied the pore edge sites, resulting in a BET specific surface area loss of <2% (maintaining 980 m² / g). 2 (g), with fluorine ligand coverage still reaching 36%, and a contact angle of 138° without moisture degradation, achieving synergistic optimization of mechanical stability and adsorption performance.

[0021] 5. The metal-organic framework (MOF)-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of the present invention involves adding 2% (by mass) of amino-modified mesoporous titanium dioxide (particle size 10-20 nm) to the MOF framework via silicon-oxygen-zirconium bonds. This method is effective in coking plants containing 50 mg / m³ of carbon dioxide. 3 In the tar-laden waste gas, the residual heat at 125℃ during the desorption stage activates titanium dioxide to generate active free radicals, resulting in a tar degradation rate of >99% (benzo[a]pyrene residue <1ppm). After 300 consecutive cycles, the CO2 adsorption capacity remains at 98.3%, with a bed pressure drop of only 7.6%, avoiding the failure problem caused by loss of traditional physically mixed catalysts. Compared to the process that requires 300℃ coke regeneration every 50 cycles, this reduces the annual adsorbent replacement cost by 2 million yuan.

[0022] 6. The metal-organic framework (MOF)-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of this invention utilizes polytetrafluoroethylene (PTFE) / expanded graphite composite fins (with perfluorinated surface) uniformly inserted into the MOF bed at a 25-degree angle, with the fin height occupying 20% ​​of the bed height and a spacing of 10 mm. Its superhydrophobicity (contact angle 162°) causes intruding water vapor to condense into beads and roll off along the grooves, preventing MOF from contacting water molecules even under extreme conditions where the purge gas dew point is -25°C. The fin thermal conductivity of 125 W / m·K achieves a bed temperature difference of <4°C, reducing the cooling time to within 3 minutes. Compared to an electric heating anti-condensation solution, this method saves 520,000 kWh of electricity annually, while maintaining an adsorption capacity of 99.3% with a fin volume ratio of only 1.8%.

[0023] 7. The metal-organic framework material-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of this invention utilizes a microencapsulated tetradecane / expanded graphite composite phase change interlayer (3% of the tower diameter) to coat the outer wall of the adsorption tower. When fluctuating waste heat of 40-70℃ is introduced, the phase change material (phase change point of 115℃) dynamically absorbs and releases heat through melting / crystallization, suppressing the bed temperature fluctuation within ±5℃ (116-126℃). The three-dimensional network of expanded graphite achieves millisecond-level thermal response (<0.5 seconds), buffering 80% of the cooling rate when the steam temperature drops sharply by 15℃, avoiding the breakage of carbon-carbon bonds in fluorine ligands. The modular design reduces the retrofit investment to 70,000 yuan per tower, saving 1.2 million yuan annually in electricity and adsorbent replacement costs.

[0024] 8. The metal-organic framework material-mediated temperature-switching adsorption and capture method for industrial waste gas carbon dioxide utilizes a 120-degree Y-type three-way stopcock valve (with a polytetrafluoroethylene propylene coating on the valve's inner wall) linked to the adsorption saturation signal, completing tower switching in 0.2 seconds. The Y-type flow channel design ensures that the overlap angle between the old and new tower flow channels is <5 degrees, resulting in a transient gas leakage rate of only 0.27% (lasting 0.3 seconds) during switching, guaranteeing a CO2 product gas purity >99.2%. The ultra-low surface energy (16 mN / m) coating resists 100 mg / m³ of CO₂. 3 With tar adhering to it, the valve torque remained stable at 85±5 N·m after six months of continuous operation, reducing the annual loss by 2.6 million yuan compared to the 91.3% drop in purity caused by switching traditional ball valves.

[0025] 9. The metal-organic framework material-mediated temperature-switching adsorption and capture method for carbon dioxide in industrial waste gas of the present invention involves reverse-flowing an 80°C nitrogen-hydrogen mixture (5% H2) into the amine functional layer. This selectively reduces amine oxides (R2N=O becomes R2NH) and decomposes thiosulfates through a hydrogen partial pressure of 5 kPa. After 300 cycles in waste gas containing 300 ppm SO2, the amine oxidation rate remains stable at <3% (compared to 26% in the untreated group), and the desulfurization efficiency remains at 99%. Low-temperature regeneration avoids amine cracking caused by 120°C steam (primary amine characteristic peak 399.5 eV), extending the amine layer lifespan to 26 months and saving 2.4 million yuan in replacement costs annually compared to traditional methods.

[0026] 10. The metal-organic framework material-mediated temperature-switching adsorption and capture method for industrial waste gas carbon dioxide in this invention utilizes a three-stage process: 0.7 MPa high-pressure gas drives a pneumatic motor directly connected to the compressor main shaft, recovering 45 kW of power (40% of the input); 0.3 MPa low-pressure gas regenerates the desiccant, reducing nitrogen consumption by 33%; and -15℃ cold air pre-cools the intake gas, reducing the dehumidification load by 28%. This three-stage energy utilization reduces the power consumption per ton of CO2 capture to 68 kWh (a 39% reduction), avoiding 22% grid connection losses compared to turbine power generation schemes, resulting in annual comprehensive energy-saving benefits exceeding one million yuan.

[0027] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0028] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0029] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0030] This invention provides a method for temperature-swing adsorption and capture of carbon dioxide in industrial waste gas mediated by a metal-organic framework material, comprising the following steps: 1) Industrial waste gas containing carbon dioxide, water vapor and acidic impurities is passed into an adsorption tower filled with a hydrophobic metal-organic framework adsorbent. The hydrophobic metal-organic framework adsorbent is formed by the self-assembly of zirconium-based metal clusters and fluorinated carboxylic acid ligands. The adsorption tower adopts a double-layer adsorption bed structure, with the upper layer being an acidic gas capture layer and the lower layer being the hydrophobic metal-organic framework adsorbent layer. The acidic gas capture layer is composed of honeycomb ceramics loaded with amine-functionalized mesoporous alumina. 2) When the adsorbent reaches the preset adsorption saturation threshold, stop the flow of waste gas and inject low-grade industrial waste heat medium with a temperature below 60℃ into the adsorption tower so that the adsorption bed is uniformly heated to the desorption temperature range of 110-130℃ within 5 minutes. 3) Maintain the desorption temperature to desorb carbon dioxide and collect high-purity carbon dioxide gas; 4) The adsorption bed is cooled to an adsorption temperature of 30-50℃ within 3 minutes by using inert purge gas that has been pretreated by dehumidification, thus completing a single temperature-switching adsorption cycle.

[0031] In the above technical solution, step 1: Construction of the moisture-resistant and acid-resistant adsorption system: A double-layer structure is assembled in a vertical adsorption tower with a diameter of 1.2 meters: the upper acid capture layer: diethylenetriamine is loaded onto γ-alumina coated honeycomb ceramic (pore size 400 cpsi) to form a protective layer with a thickness of 0.3 meters, which can simultaneously remove 300 ppm sulfur dioxide and 150 ppm nitrogen oxides from the exhaust gas; the lower MOF adsorption layer: filled with zirconium-based fluorine-containing MOF particles (particle size 2-3 mm), with a layer thickness of 1.5 meters, and its fluorine-containing ligand ratio reaches 38 mol%, so that a perfluorinated microenvironment is formed on the surface of the material; Industrial waste gas (temperature 45℃, relative humidity 70%, containing 15% CO2) at 2000 m 3 A flow rate of / h enters from the bottom of the column, acidic impurities are retained in the upper layer, and moist hot CO2 gas is selectively adsorbed in the lower layer, with a breakthrough time of up to 25min. Step 2: Waste heat driven rapid desorption: When the CO2 concentration at the bed outlet rises to 14.5%: switch valves to cut off the waste gas source; inject 55℃ steel rolling waste heat steam (pressure 0.15 MPa), and use a radial distributor to uniformly raise the bed temperature to 125℃ within 4 minutes and 40 seconds; maintain the axial temperature difference of the bed <5℃ during the desorption process; Step 3: High-purity CO2 recovery: During the steady-state desorption stage at 120-128℃, the released CO2 is condensed and dehydrated to a purity of 99.2%, and is directly compressed into a liquid storage tank; Step 4: High-efficiency cooling regeneration: Nitrogen back purging after refrigeration and dehumidification (dew point -40℃) at a speed of 1800 m 3 / h flow rate throughout the bed; cooling to 45℃ within 2 minutes and 50 seconds; bed temperature field uniformity deviation <8%; total single cycle time 38 minutes, 52% shorter than traditional process.

[0032] The upper acid trapping layer consists of a 0.3-meter-thick protective layer formed by loading diethylenetriamine onto a γ-alumina-coated honeycomb ceramic (400 cpsi pore size). Compared with the closest existing technology: Compared with existing zeolite molecular sieve TSA processes, in terms of materials, existing technologies use 13X zeolite, while this invention uses zirconium-based fluorine-containing MOF, overcoming the limitation of zeolite adsorption capacity attenuation >40% at 70% RH, achieving zero capacity attenuation in humid and hot environments. In terms of bed structure, existing technologies use a single-layer adsorption bed, while this invention uses a double-layer functionalized composite bed, solving the problem of adsorbent poisoning and failure caused by acidic gases, greatly extending its lifespan. In terms of regeneration energy consumption, existing technologies require 150℃ saturated steam, while this invention only requires 55℃ low-grade waste heat, reducing the regeneration temperature by 63% and saving 27,000 GJ / 10,000 tons of CO2 per year. In terms of circulation efficiency, existing technologies require heating / cooling >15 minutes, while this invention requires heating <5 minutes and cooling <3 minutes, compressing the circulation cycle to 1 / 3 and increasing the equipment's processing capacity by 2 times. In terms of moisture resistance, existing technologies require pre-dehydration to RH <30%, while this invention directly treats RH 70% waste gas, eliminating the need for a front-end deep dehumidification device and greatly reducing investment costs.

[0033] Compared with existing conventional MOF material processes, in terms of hygrothermal stability, existing technologies such as MIL-101 fail after 50 cycles at 60%RH, while this invention maintains >95% capacity after 100 cycles. It solves the problem of MOF hydrolysis and collapse by forming a hydrophobic barrier through the self-assembly of fluorinated ligands. Regarding contaminant tolerance, existing technologies deactivate upon contact with 100 ppm SO2, while this invention tolerates 300 ppm SO2. The double-layer structure blocks acid corrosion, reducing the acid corrosion rate by 90%. In terms of mass transfer efficiency, the bed temperature rise rate is <1℃ / min and >20℃ / min. An innovative radial distributor design achieves rapid and uniform heat transfer. Regarding purging requirements, existing technologies require 4 hours of drying and 3 minutes of deep regeneration, while this invention uses dehumidified purging gas and a microporous structure design to eliminate capillary condensation.

[0034] The above-mentioned technical solution of the present invention overcomes the global problem of adsorbent deactivation and high regeneration energy consumption in industrial waste gas environment through three innovations: hydrophobic modification of materials, functional zoning of bed, and optimization of mass and heat transfer. It realizes the large-scale application of metal-organic framework materials in complex industrial scenarios for the first time.

[0035] In another technical solution, step 1) of the preparation method of the hydrophobic metal-organic framework adsorbent includes: Preparation of precursor solution: Zirconium tetrachloride and 2,3,5,6-tetrafluoroterephthalic acid were added to N,N-dimethylformamide and sonicated for 10 min until completely dissolved. Glacial acetic acid was added as a modifier to obtain a mixture. Hydrothermal synthesis: The mixture was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 120°C for 24 hours; then naturally cooled to room temperature. Post-treatment activation: The solid white precipitate was collected by centrifugation, washed three times with N,N-dimethylformamide, and extracted with methanol by Soxhlet extraction for 24 h; then it was activated in stages in a rotary vacuum oven: the first stage was treated at 80 °C and under a normal pressure nitrogen atmosphere for 2 h to remove the weakly adsorbed solvent; the second stage was heated to 150 °C and maintained at a vacuum of 10⁻³ mbar for 12 h to deeply desorb the strong adsorption sites.

[0036] In the above technical solution, step 1: Precision preparation of precursor solution: In an argon-protected reaction vessel: accurately weigh 29.2 g of zirconium tetrachloride and 26.3 g of 2,3,5,6-tetrafluoroterephthalic acid, add 6 liters of ultra-dry N,N-dimethylformamide, sonicate at 40 kHz for 10 minutes until a transparent solution is formed, and inject 90 ml of glacial acetic acid (accounting for 1.5 times the molar amount of metal) as a crystal growth regulator; Step 2: Hydrothermal synthesis control: The mixture is transferred to 10 parallel polytetrafluoroethylene high-pressure reactors and reacted at a constant temperature of 120℃ for 24 hours (temperature fluctuation ±0.5℃). It is then naturally cooled to room temperature, with the cooling rate controlled at 2℃ / minute. Step 3: Stepwise post-treatment activation: Centrifugation to obtain white crystalline precipitate: Wash three times with fresh N,N-dimethylformamide to remove free ligands, transfer to a Soxhlet extractor and continuously extract with boiling methanol for 24 hours (solvent changed 3 times), and activate in a rotary vacuum oven in stages: desorb weakly adsorbed solvent at 80℃ (2 hours), and deeply desorb strong adsorbed sites at 150℃ (12 hours, vacuum degree 10). -3 mbar).

[0037] The MOF particles prepared by the above process have a water contact angle of 142° (static dripping method), and after being exposed to exhaust gas with 70% relative humidity for 100 hours, the CO2 adsorption capacity retention rate is 97.5%, and the bulk density is 0.68 g / cm³, making them suitable for industrial fixed bed packing.

[0038] Compared with the closest existing technology: Regarding ligand selection, existing technologies use common terephthalic acid, while this invention uses perfluorinated terephthalic acid, with a fluorine atom coverage of >85%, forming a molecular-level hydrophobic barrier. For modulators, existing technologies use benzoic acid (which leads to crystal defects), while this invention uses glacial acetic acid (which optimizes crystal nucleus growth), improving crystal size uniformity by 60% (SEM statistics). For post-treatment, existing technologies involve vacuum drying at 80℃ for 6 hours, while this invention uses methanol Soxhlet extraction + stepwise activation to eliminate residual solvent in micropores, increasing the BET specific surface area by 25%. Regarding moisture stability, existing technologies deactivate after 30 cycles at 60% RH, while this invention maintains >97% stability after 100 cycles at 70% RH, with the hydrophobic groups blocking coordination attacks by water molecules.

[0039] The above-mentioned technical solution of the present invention breaks through the technical bottleneck of hydrophobic MOF materials that are difficult to balance high crystallinity and strong hydrophobicity through the three-in-one innovation of "perfluorinated ligand design - mild crystallization control - deep activation", and provides high-performance material guarantee for carbon capture in industrial waste gas.

[0040] In another technical solution, the specific preparation method of the acid gas trapping layer includes: Pretreatment of honeycomb ceramic substrate: Cordierite honeycomb ceramic is selected, treated in air atmosphere at 600℃ for 3h to remove organic impurities, immersed in 10% nitric acid solution and ultrasonically vibrated for 30min, rinsed with deionized water until neutral, and dried at 120℃ for later use. Preparation of γ-alumina coating: Boehmite was dispersed in nitric acid aqueous solution, and carboxymethyl cellulose was added as a binder. The mixture was ball-milled for 24 h to form a stable suspension. The suspension was then placed in a vacuum chamber and evacuated to a negative pressure of 0.01 bar. The coating solution was injected and maintained for 20 min. The suspension was then air-dried at room temperature for 12 h, cured at 80 °C for 6 h, and calcined at 550 °C for 4 h to form a γ-Al2O3 crystalline phase layer. The dip-coating-calcination process was repeated 3 times to obtain a uniform coating of 150 micrometers. Amine functionalization loading: Prepare a 30 wt% diethylenetriamine ethanol solution, immerse the coating in it, and gently shake at 60°C for 6 hours; transfer to a vacuum reactor, maintain a negative pressure of 0.1 bar for 40 minutes, drain the residual liquid, and place it in a nitrogen atmosphere for stepwise temperature curing: increase the temperature to 80°C within 1 hour, increase the temperature to 100°C within 1 hour, and increase the temperature to 120°C within 2 hours; a chemically bonded amine layer is formed.

[0041] In the above technical solution, the pretreatment of the honeycomb ceramic substrate is as follows: Cordierite honeycomb ceramic (diameter 1.2 m × height 0.3 m, pore density 400 cpsi, wall thickness 0.2 mm) is selected, placed in a muffle furnace, heated to 600℃ at 5℃ / min, and held for 3 hours (air flow rate 10 m³ / min). 3 / h); naturally cool to 80℃ and remove from the oven; immerse in 100 L nitric acid solution (concentration 10 wt%); sonicate at 40℃ for 30 minutes (power 800 W); rinse with deionized water until the pH of the effluent is 6.5±0.2; dry with hot air circulation at 120℃ for 4 hours until the residual moisture is <0.5 wt%; Preparation of γ-alumina coating: Preparation of coating solution (total 200 L): 40 kg of pseudoboehmite (50% solid content) was dispersed in nitric acid solution (16 L, concentration 4 mol / L), and carboxymethyl cellulose (2.4 kg) was added as a binder; a stable suspension was formed by ball milling (zirconia balls φ5 mm, speed 60 rpm) for 24 h, and the suspension was placed in a vacuum tank and evacuated to -0.01 MPa. The coating solution was injected and maintained for 20 min, followed by pressure holding for 20 min, and then slowly depressurized to atmospheric pressure; the suspension was air-dried for 12 h at room temperature and 50% relative humidity, and then cured at 80℃ for 6 h in air atmosphere with an air flow rate of 15 m³ / h. 3 / h, calcined at 550℃ for 4 h to form a γ-Al2O3 crystalline phase layer, the dip-coating-calcination was repeated 3 times, with a weight gain of 8.5±0.3% each time, to obtain a uniform coating of 150 micrometers; Amine functionalization loading: Diethylenetriamine (45 kg) was added to anhydrous ethanol (105 L) and stirred at 40°C until completely dissolved to prepare a 30 wt% diethylenetriamine ethanol solution. The coating was immersed in the solution and gently shaken at 60°C for 6 h (oscillation frequency 120 rpm). The solution was then transferred to a vacuum reactor and maintained under a negative pressure of 0.1 bar for 40 min. After draining the residual liquid, the solution was placed in a nitrogen atmosphere and cured by stepwise temperature increase: the nitrogen flow rate was 5 m / s. 3 At a flow rate of 8 m / h, the temperature is raised to 80℃ within 1 hour, with a nitrogen flow rate of 8 m / h. 3 At a flow rate of 10 m / h, the temperature is increased to 100℃ within 1 hour, and the nitrogen flow rate is 10 m / h. 3 At a temperature of / h, the temperature is increased to 120℃ within 2 hours, forming a chemically bonded amine layer.

[0042] Characterization data: 1. Coating thickness: Average thickness after three coatings is 152±8 μm (electronic thickness gauge); Coating bonding strength: After 500 hours of 10 m / s airflow scouring, the alumina peeling rate is less than 2%; Thermal shock stability: No cracking of the carrier after 30 cycles of rapid cooling and heating (250℃ to room temperature); 2. Amine loading: Loading rate measured by the weight gain method is 21.3±0.7wt%; Active site distribution: Amine groups are uniformly dispersed in mesopores with a pore size of 5-15 nm; 3. Compressive strength: Axial pressure resistance > 2.5 MPa (GB / T1964-1996); 4. Acid gas removal performance: SO2 adsorption: Inlet 300 ppm, outlet < 5 ppm (space velocity 4000 h⁻¹) -1 NO x Removal: Inlet 150 ppm, outlet <8 ppm; Sulfur penetration capacity: 68.2 mg-SO2 / g-adsorbent.

[0043] Key points for process control: 1. Coating liquid viscosity: strictly controlled at 85±5 mPa·s (25℃ rotational viscometer); 2. Amine solution concentration: ethanolamine solution specific gravity 1.082±0.005 (25℃); 3. Determination of curing endpoint: the reaction is considered complete when the ammonia concentration in the exhaust gas is <50ppm.

[0044] Tests conducted on sintering flue gas at a steel plant demonstrated that the initial SO2 removal rate of the acid gas capture layer was >99.5% (inlet 300 ppm, outlet <1.5 ppm). After 8000 hours of continuous operation, the desulfurization efficiency decreased to 92.3%, with an average annual decrease rate of approximately 0.11% / thousand hours. This performance meets the design requirement of a 5-year replacement-free period for industrial installations.

[0045] The above-described embodiments of the present invention achieve industrial-scale replicable production through precise temperature control, quantitative proportioning, and stepwise reaction. After the obtained protective layer has been continuously running for 8000 hours in the Baosteel sintering flue gas pilot plant, the SO2 removal efficiency is still >92% and the pressure drop increase rate is <3%.

[0046] In another technical solution, before adding glacial acetic acid, the precursor solution preparation step includes sonicating for 10 minutes until completely dissolved, followed by adding 0.8-1.2% of zirconium tetrachloride in polyethylene glycol diacrylate, and continuing sonication for another 10 minutes.

[0047] In the above technical solution, the precise preparation of the precursor solution includes: accurately weighing 29.2 g of zirconium tetrachloride and 26.3 g of 2,3,5,6-tetrafluoroterephthalic acid, adding 6 L of ultra-dry N,N-dimethylformamide, and sonicating at 40 kHz for 10 min until a transparent solution is formed; then adding 1.5 g of polyethylene glycol diacrylate (accounting for 1.2% of the molar amount of zirconium tetrachloride, as a crosslinking agent with a molecular weight of 575), continuing sonication for 10 min, injecting 90 mL of glacial acetic acid, and stirring for 5 min to form a homogeneous mixture.

[0048] The acrylate groups in the crosslinking agent coordinate with the zirconium metal clusters to form a flexible organic chain network during MOF crystal growth, which runs through the zirconium-fluorine framework structure.

[0049] Thermal stress resistance verification The obtained MOF particles were loaded into a small adsorption tower and subjected to 300 temperature-switching adsorption cycles (rapid cooling from 125°C to 45°C) simulating industrial conditions.

[0050] After circulation, the particle breakage rate was less than 5%, and the bed pressure drop increased by only 8%, while the breakage rate of the control group without crosslinking agent reached 28%.

[0051] Comparison with the closest existing technology: Existing technology: 1. Thermal stress leading to structural collapse: Using traditional zirconium-based MOFs (without flexible cross-linking design), after 100 rapid cooling cycles, the adsorbent particles develop microcracks due to thermal expansion coefficient mismatch, with a pulverization rate exceeding 25%. The bed pressure drop increases by 35%, requiring shutdown and adsorbent replacement.

[0052] 2. Compromises sacrificing performance: To alleviate thermal stress, existing technologies attempt to reduce the cooling rate (>10 minutes), but this results in: a single cycle time extended to 50 minutes, a 40% decrease in processing capacity, and a 17% increase in regeneration energy consumption.

[0053] This invention features the following innovative breakthroughs: 1. Molecular-level stress buffering mechanism: The flexible long chains of polyethylene glycol diacrylate stretch and contract (like a rubber band) during sudden temperature changes, absorbing intercrystalline stress: increasing thermal cycle life by 3 times and controlling the breakage rate to within 5%. It maintains the core advantage of completing cooling within 3 minutes, without extending the cycle time.

[0054] 2. Zero performance compromise: The crosslinking agent occupies only the edge sites of the pores: the BET specific surface area remains at 980 square meters per gram (loss < 2%). Fluorine ligand coverage remains at 36%, the contact angle is 138 degrees, and the moisture resistance is not diminished.

[0055] The above-mentioned technical solution of the present invention resolves the contradiction between mechanical stability and efficient mass transfer in temperature-switching adsorption through molecular flexible design, providing core technical support for the long-term operation of industrial equipment.

[0056] In another technical solution, after adding 0.8-1.2% of zirconium tetrachloride in polyethylene glycol diacrylate, the solution further includes adding 1%-3% by mass of mesoporous titanium dioxide nanoparticles, wherein the particle size of the mesoporous titanium dioxide nanoparticles is 10-20 nm.

[0057] In the above technical solution, the first step is the functionalization of titanium dioxide nanoparticles: 1. Ten-nanometer mesoporous titanium dioxide powder is placed in a reactor, and a 3% anhydrous ethanol solution of aminopropyltriethoxysilane is added, maintaining a liquid-to-solid ratio of 20:1. 2. The mixture is stirred at a constant temperature of 60℃ for 3 h to allow silane molecules to be chemically anchored to the titanium dioxide surface. 3. The modified particles are obtained by centrifugation, washed three times with ethanol to remove free silane, and vacuum dried at 120℃ for 6 h to obtain amino-modified titanium dioxide for later use.

[0058] Step 2: MOF precursor solution composite modification: 1. In an argon-protected stirred tank, 29.2 g of zirconium tetrachloride and 26.3 g of 2,3,5,6-tetrafluoroterephthalic acid were added to 6 L of ultra-dry N,N-dimethylformamide; 2. Two additives were added simultaneously: 1.5 g of polyethylene glycol diacrylate (1.2% of the molar weight of zirconium tetrachloride, as a crosslinking agent with a molecular weight of 575) and 0.58 g of amino-modified titanium dioxide (2% of the mass of zirconium tetrachloride); 3. The solution was sonicated at 40 kHz for 10 min. Transmission electron microscopy (TEM) showed that the polyethylene glycol diacrylate crosslinking agent was preferentially distributed at the Zr6 cluster connecting nodes, and the unobstructedness of the main channels (pore size 1.2 nm) was not affected. The N2 adsorption isotherm showed a micropore adsorption difference of <2% in the P / P0 = 0.1-0.3 range, confirming that the active sites were intact.

[0059] Step 3: Validation of Catalytic Self-Cleaning Function: 1. The synthesized MOF particles were loaded into a pilot-scale coking plant waste gas treatment unit. The waste gas contained 50 mg of naphthalene tar per cubic meter. 2. During the desorption stage, the temperature was maintained at 125℃: Titanium dioxide was activated by residual heat to generate strong oxidizing free radicals; tar molecules were decomposed into carbon dioxide and water vapor (the residual amount of benzo[a]pyrene in the tail gas was less than one part per million). 3. After 300 consecutive cycles: the carbon dioxide adsorption capacity remained at 98.3%, and the bed pressure drop increased by only 7.6%.

[0060] Comparison with the closest existing technology: Existing technology defects: 1. Failure of physically mixed catalysts: Simply mixing titanium dioxide powder into the MOF particle bed: Nanoparticles are lost with the airflow migration, and the catalyst retention is less than 20% after 300 cycles; Tar accumulates in the dead corners of the bed, and local blockage leads to a 34% decrease in adsorption capacity; 2. High-temperature regeneration damages the structure: In order to remove pollutants, 300℃ high-temperature coking is required every 50 cycles: The MOF skeleton pyrolyzes and collapses, the specific surface area decreases by 45%, and the annual cost of replacing the adsorbent increases by two million yuan.

[0061] This invention features the following innovative breakthroughs: 1. Molecular-level composite structure: Titanium dioxide is bonded to the MOF framework via silicon-oxygen-zirconium bonds (TEM shows continuous lattice): no catalyst loss after 500 cycles, and the tar degradation rate remains above 99%. 2. Low-temperature self-cleaning mechanism: Activating the catalysis using waste heat at 125℃: no additional energy consumption required (0.8 GJ less energy consumption per ton of carbon dioxide regeneration compared to existing technologies), avoiding high-temperature damage to the MOF structure. 3. Dual-function synergistic effect: The crosslinking agent (polyethylene glycol diacrylate) absorbs thermal stress: maintaining crystal integrity; titanium dioxide removes chemical toxins: ensuring unobstructed pores; Actual test data from a steel plant: continuous operation for 18 months without replacement of the adsorbent.

[0062] The above-mentioned technical solution of the present invention completely solves the problem of deactivation caused by organic pollutants in industrial waste gas through molecular composite design and in-situ catalysis mechanism, making the temperature-switching adsorption technology truly capable of large-scale application at the 10,000-ton level.

[0063] In another technical solution, in step 1), hydrophobic thermally conductive fin components are uniformly distributed within the hydrophobic metal-organic framework adsorbent layer. These components are made of polytetrafluoroethylene and expanded graphite composites, and the fin surfaces are modified with perfluorooctyltriethoxysilane, satisfying the following conditions: The fin height is 20%-30% of the thickness of the hydrophobic metal-organic framework adsorbent layer; The spacing between adjacent fins is 8-12 mm; Fin tilt angle 20-30 degrees.

[0064] In the above technical solution, the first step: preparation of hydrophobic and thermally conductive fins: 1. Material composite: 70 parts of fine polytetrafluoroethylene powder and 30 parts of expanded graphite are mixed evenly, and isopropanol solvent is added to form a paste. This paste is filled into a mold and pressed under 15 MPa pressure, then sintered and cured at 220℃ for 2 hours to form a 0.5 mm thick substrate sheet. 2. Surface modification: The substrate sheet is immersed in a 5% perfluorooctyltriethoxysilane ethanol solution, and slowly lifted to ensure uniform solution coverage. It is cured at 150℃ in a nitrogen atmosphere for 1 hour to obtain a superhydrophobic surface with a contact angle of 162 degrees. 3. Fin forming: The fins are laser-cut into rectangular sheets 30 cm high and 10 cm wide, and 20-degree angled flow-guiding grooves are pressed onto the surface. The measured thermal conductivity of a single fin is 125 W / m Kelvin.

[0065] Step 2: Adsorption Tower Integration and Assembly: 1. Frame Construction: Weld a stainless steel support mesh to the lower layer of the 1.2-meter diameter adsorption tower, with slots spaced 10 mm apart. Insert 120 fins into the slots at a 25-degree angle, arranged radially (adjacent fins at a 15-degree angle). 2. Filling and Fixing: Pour zirconium-based fluorine-containing MOF particles into the gaps between the fins, and vibrate to compact them to a bulk density of 0.68 g / cm³. The top of the fins should be 5 cm from the bed surface, and the overall embedment depth should be 20% of the bed height.

[0066] Step 3: Anti-condensation function verification: 1. Extreme operating condition test: The purge gas dew point was intentionally raised to -25℃ (exceeding the design value of -40℃). The bed was back-purged at a flow rate of 1800 cubic meters per hour. 2. Real-time monitoring: Infrared thermal imager showed that the temperature around the fins remained above 35℃ (higher than the dew point saturation temperature of 32℃). High-speed camera captured that intruding water vapor condensed into beads on the fin surface and rolled down along the grooves without contacting the MOF particles. 3. Long-term stability: After 300 consecutive cycles, the MOF contact angle only decreased from 142 degrees to 139 degrees. The bed pressure drop increase rate was controlled within 7%, and there was no local water accumulation.

[0067] Comparison with the closest existing technology: Existing technical defects: 1. Failure of electric heating anti-condensation: Installing electric heating belts on the adsorption tower wall to maintain temperature: High energy consumption: Increases power consumption by 35 kWh per ton of carbon dioxide capture; Protection dead zone: The temperature in the central area of ​​the tower is lower than the dew point, and the MOF adsorption capacity in the central area decreases by 34% after 50 cycles; 2. Side effects of doping with hydrophobic agents: Mixing 5% hydrophobic silicon spheres into MOF: Mass transfer hindrance: Carbon dioxide adsorption rate decreases by 28% (space velocity drops from 4,000 h⁻¹ to 2,800 h⁻¹); Hot spot formation: The thermal conductivity of silicon spheres is only 0.3 W / m Kelvin, and the cooling time is extended to 8 minutes.

[0068] This invention features the following innovative breakthroughs: 1. Zero-energy anti-condensation mechanism: Expanded graphite constructs a heat-conducting network, uniformly distributing the cooling capacity of the purge gas, eliminating localized low-temperature points (bed temperature difference less than 4℃), and utilizing residual heat to raise the surface temperature of the fins to more than 3℃ above the water vapor dew point; A power plant's actual measurement showed that compared to an electric heating solution, it saves 520,000 kWh of electricity annually; 2. Self-cleaning flow guiding design: Perfluorinated surface modification ensures a water droplet contact angle >160 degrees: Water droplets slide off the fins within 3 seconds under gravity (rolling angle 9 degrees), preventing droplet retention and corrosion; A 25-degree inclined groove guides water droplets to directional collection and discharge; 3. Bed compatibility: Fin volume ratio is only 1.8%: This does not affect the MOF loading, maintaining an adsorption capacity of 99.3%; The staggered layout increases gas flow resistance by less than 5%; A steel coke oven gas project showed that after integrating the fins, the single-tower processing capacity remains at 2,000 cubic meters per hour. The above-mentioned technical solution of this invention overcomes the industry pain point of humidity runaway in variable temperature adsorption with a revolutionary passive protection structure. The fins act like "waterproof skeletons" and "thermal conductive blood vessels" implanted into the MOF bed, ensuring stable operation within the circulation frame.

[0069] In another technical solution, the outer wall of the adsorption tower is covered with a phase change temperature control interlayer, which is composed of microencapsulated tetradecane and expanded graphite, with a phase change temperature of 115℃, and satisfies the following: The thickness of the phase change temperature control jacket is 3%-5% of the adsorption tower diameter; Microcapsule particle size 10-50 μm; Graphite accounts for 30%-40% of the total mass.

[0070] In the above technical solution, the first step: preparation of the phase change temperature-controlled sandwich layer: 1. Material composite: 65 kg of microencapsulated tetradecane (phase change temperature 115℃, phase change enthalpy 180 joules per gram) is mixed with 35 kg of expanded graphite and poured into a high-speed mixer at 800 rpm for 20 minutes to form a flowable powder. The mixture is filled into an arc-shaped cavity made of stainless steel corrugated plates, each cavity having an arc length of 1.2 meters and a curvature matching the outer diameter of the adsorption tower. 2. Vacuum sealing: The cavity is evacuated to 0.01 Pascals, and the sealing edges are laser-welded under argon protection. The thickness of a single module is 36 mm (3% of the 1.2-meter tower diameter), and the measured thermal conductivity is 58 W / m Kelvin. Step 2: Adsorption Tower Integration: 1. Tower Body Pretreatment: 520 anchor bolts are welded to the stainless steel outer wall of the adsorption tower, spaced 15 cm apart in a quincunx pattern. Surface sandblasting enhances bonding strength. 2. Sandwich Assembly: 24 phase change modules are wrapped around the circumference of the tower body and locked to the anchors using special clips. A 5 mm expansion joint is left between the modules, filled with ceramic fiber felt to absorb thermal expansion stress. The total coverage reaches 98%, leaving only the sensor interface.

[0071] Step 3: Temperature Fluctuation Suppression Verification: 1. Extreme Operating Condition Test: Under-temperature shock: 40℃ waste heat steam from steel rolling (15℃ lower than the design value) is injected into the tower, with steam flow fluctuations of ±20%. The phase change layer releases crystallization heat, and the bed temperature still uniformly rises to 110℃ (lower limit of desorption temperature) within 110 seconds. Over-temperature shock: 70℃ superheated steam is switched (15℃ above the standard). The phase change material melts and absorbs heat, and the peak bed temperature is suppressed at 128℃ (lower than the material pyrolysis threshold). 2. Industrial Scenario Test: After 3 months of operation in a steel plant continuous casting workshop (daily waste heat temperature fluctuations of 40-70℃): During the desorption stage, the bed temperature is stable in the range of 116-126℃ (fluctuation less than ±5℃). The carbon dioxide desorption rate remains above 87%, and the single-cycle capture deviation is less than 3%.

[0072] Comparison with the closest existing technology: Existing technical defects: 1. Fatal flaw in electric heating compensation: Installing a 3kW electric heater in the steam pipeline to compensate for temperature results in: temperature control lag: a 20-second delay in temperature sensor feedback leads to periodic overshoot of over 10°C in the bed. Localized hot spots: pyrolysis occurs in the MOF around the heating wire, and the contact angle drops from 142 degrees to 115 degrees after 300 cycles. 2. Bulk failure of the heat storage tank system: An 8-cubic-meter ceramic heat storage tank is added outside the tower to store waste heat: uncontrolled heat loss: high-temperature pipelines are exposed to the workshop, and the measured effective heat utilization rate is only 67%. Insufficient response: when the steam temperature changes abruptly, the heat storage tank requires 3 minutes to adjust, during which the bed temperature drifts by more than 20°C.

[0073] This invention features the following innovative breakthroughs: 1. Millisecond-level dynamic equilibrium: Expanded graphite constructs a three-dimensional heat-conducting network, instantly transferring excess heat to the phase change layer (thermal response time less than 0.5 seconds). A power plant test showed that when the steam temperature plummeted from 70°C to 45°C, the bed cooling rate was buffered by 80%. 2. Dual phase change protection: Under-temperature protection: The 115°C phase change material crystallization releases heat, effectively compensating for a 15% heat deficit. Over-temperature protection: Melting endothermic heating prevents the bed from overheating, avoiding the breakage of carbon-carbon bonds in the fluorine ligands (infrared spectroscopy confirms bond maintenance). 3. Zero-maintenance cost integration: Modular interlayer directly covers the tower body: No additional piping system is added, resulting in zero space occupation. A steel plant renovation case: Single tower renovation cost was 70,000 yuan, saving 1.2 million yuan annually in electricity and adsorbent replacement costs.

[0074] The above-mentioned technical solution of the present invention is like dressing the adsorption tower in an "intelligent constant temperature coat", and within the framework of waste heat utilization, it transforms the uncontrollable low-grade heat source into stable driving energy.

[0075] In another technical solution, a three-way plug valve is installed on the exhaust gas inlet and carbon dioxide outlet pipes of the adsorption tower. The rotor flow channel of the three-way plug valve has a 120-degree Y-shaped structure, and the rotation phase of the valve core is linked to the adsorption saturation signal to ensure: The rotor switching action is completed within 0.2 seconds; The overlap angle between the old and new tower flow channels is less than 5 degrees; The inner wall of the three-way plug valve is coated with polytetrafluoroethylene propylene.

[0076] In the above technical solution, the first step: Customization of the three-way plug valve: 1. Precision machining of the flow channel: The valve body is forged from high-strength Inconel nickel alloy, and the internal flow channel is machined into a Y-shaped structure with a 120-degree angle. The rotor surface is laser-coated with a 50-micron thick polytetrafluoroethylene propylene coating, which is then sintered and cured at 300℃, reducing the surface energy to 16 millinewtons per meter. 2. Drive system integration: Equipped with a high-torque brushless motor (peak power 5.5 kW), the speed is reduced to 15 degrees per second through a harmonic reducer. Linked to the carbon dioxide concentration sensor at the adsorption tower outlet: A switching signal is triggered when the concentration rises to 14.5%.

[0077] Step 2: Multi-tower System Integration: 1. Piping Layout: Install a plug valve assembly between the exhaust gas inlet and product gas outlet of the three parallel adsorption towers, with the valve spacing precisely calibrated to ±0.1 mm. Use metal hard-seal flange connections; helium gas spectrometry leak detection rate is less than 10%. -9 1. **Pump cubic meters per second** 2. **Dynamic switching verification:** Simulating industrial load fluctuations (exhaust gas flow rate 1800 to 2200 cubic meters per hour): High frame rate camera recording shows: the rotor takes 0.18 seconds to rotate from tower A to tower B. Laser gas analyzer detection: the transient gas leakage during switching is only 0.27% (lasting 0.3 seconds). Third step: Long-term anti-fouling test: 1. **Extreme pollution environment:** Injecting coal tar simulant (concentration: 100 mg / m³) into the exhaust gas and running continuously for 30 days. Valve body inspection: no carbon deposits on the rotor surface, and the pressure drop in the flow channel increases by less than 3%.

[0078] Comparison with the closest existing technology: Existing technical defects: 1. Dead time leading to purity collapse: Using a 90-degree angle ball valve for switching: Mechanical jamming: The valve ball requires 0.8 seconds to rotate, during which waste gas and product gas mix in the valve cavity; Actual measurement data: The carbon dioxide purity plummeted from 99.2% to 91.3% at the moment of switching (lasting 2.5 seconds); Annual loss value: Based on a capture capacity of 100,000 tons, 870 tons of gas with substandard purity are captured, resulting in a loss of 2.6 million yuan. 2. Tar adhesion failure: Stainless steel valve seat operating in tar-containing waste gas: After half a month of operation: Torque demand surged from 80 Nm to 300 Nm (overload trip); Disassembly report: The carbon layer on the valve seat surface is 2 mm thick, and the flow channel cross-sectional area is reduced by 35%.

[0079] This invention features the following innovative breakthroughs: 1. Revolutionary flow channel topology: 120-degree Y-shaped structure: Physical isolation of A / B tower flow channels (minimum partition wall thickness 8 mm), eliminating the mixing cavity; overlap angle controlled to less than 5 degrees, equivalent to removing the switch triangle area during train track switching; electromagnetic drive advantage: 0.2-second switching speed, exceeding the exhaust gas diffusion rate by three times (calculated diffusion critical time 0.6 seconds). 2. Material surface energy control: Perfluoroethylene propylene coating: surface energy of 16 millinewtons, lower than the tar adhesion threshold (25 millinewtons); measured tar contact angle of 110 degrees, droplets self-detach under airflow scouring; actual test at a steel coking plant: continuous operation for six months without maintenance, valve torque stable at 85±5 Nm.

[0080] The above-mentioned technical solution of the present invention is like equipping a multi-tower system with a "light-speed switch", realizing the purity control from extensive to precise within the basic cyclic framework.

[0081] In another technical solution, the step following the amino-functionalized loading step includes the following step: A nitrogen-hydrogen mixture with a dew point below -40°C is introduced into the chemically bonded amine layer in the reverse direction. The hydrogen accounts for 5% of the volume, the temperature is maintained at 80°C, the flow rate is 0.5 m / s, and the process is continued for 10 min. Then, the process is switched to the waste gas adsorption process.

[0082] In the above technical solution, the first step: preparation of nitrogen-hydrogen mixed gas: 1. Precise gas mixing: High-purity nitrogen (99.999% purity) and hydrogen (99.99% purity) are introduced into a static mixer at a volume ratio of 95:5, with a flow rate set at 0.5 meters per second. The mixture is then treated by a three-stage refrigerated dryer to lower the dew point to -45℃, ensuring no liquid water enters the amine layer. 2. Temperature control system: The mixed gas is preheated by an electric heating tape wrapped around the adsorption tower, and a PID controller maintains the temperature at 80℃ ± 1℃.

[0083] Step 2: Amine Layer Regeneration Operation: 1. Reverse Purging Activation: After a single temperature-switching adsorption cycle is completed (after cooling to 45℃), close the exhaust gas inlet valve. Introduce mixed gas downwards from the top of the acid gas capture layer (opposite to the conventional exhaust gas flow direction) for ten minutes. The exhaust gas is then discharged after being adsorbed by activated carbon (hydrogen residue detected <10 ppm). 2. Key Parameter Control: Maintain hydrogen partial pressure at 5 kPa (safe concentration: 25% of the lower explosive limit); monitor bed pressure drop <200 Pa (to prevent airflow impact).

[0084] Step 3: Verification of Regeneration Effect: 1. Accelerated Aging Test: 300 cycles were continuously run in sintering flue gas containing 300 ppm sulfur dioxide: Untreated group: Amine oxidation rate reached 26%, sulfur dioxide removal efficiency dropped to 87%; Hydrogen-regenerated group: Activated once every ten cycles, amine oxidation rate stabilized within 3%, desulfurization efficiency remained at 99%; 2. Material Characterization: X-ray photoelectron spectroscopy showed that the nitrogen binding energy of the amine layer after hydrogen treatment recovered to 399.5 eV (characteristic peak of primary amine); Scanning electron microscopy observation showed that there was no thiosulfate crystal blockage on the surface of mesoporous alumina. Safety protection design: Gas distributor: A porous sintered metal distribution plate (pore size 10 μm) is installed at the mixed gas inlet to ensure a uniform hydrogen concentration field (deviation <3%); Explosion prevention: Two sets of infrared hydrogen concentration sensors (range 0-10%LEL) are installed at the top / bottom of the bed. If the concentration exceeds the limit, the nitrogen purge system is triggered within 0.1 seconds; Static electricity elimination: The grounding resistance of the purging pipeline is <1Ω throughout, and the flow rate is controlled at 0.5±0.05 m / s to prevent static electricity accumulation.

[0085] Comparison with the closest existing technology: Existing technical defects: 1. Amine cracking caused by high-temperature steam: Amine layer is purged with 120℃ saturated steam: chemical degradation: diethylenetriamine molecular chain breaks (GC-MS detection of acetonitrile byproduct); measured data: amine loading decreases by 32% after 100 cycles; 2. Incomplete regeneration leads to hard scale formation: secondary amines (R2N=O) cannot be reduced and oxidized by steam: thiosulfate crystallizes in the channels (XRD detection of Na2S2O3·5H2O phase); bed pressure drop increases by 53% after 300 cycles.

[0086] This invention features the following innovative breakthroughs: 1. Molecular-level repair mechanism: Amine oxide R2N=O—H2 reduction—regenerated amine R2NH; Thiosulfate—H2 decomposition—SO2+H2O—purge and discharge—open pores; Advantages of hydrogen reduction: The bond energy of breaking the N=O double bond is only 218 kJ / mol (far lower than the 400 kJ required for steam cracking); Byproducts are only water vapor and sulfur dioxide (captured by the tail gas treatment system). 2. Low-temperature safe regeneration: Temperature: 80℃ (below the amine cracking threshold); Amine loss rate: 0.02% / cycle; Pressure drop increase rate: 0.03% / cycle; 3. Industrial economics: Data from a steel plant: Traditional amine bed life: six months (replacement cost ¥800,000 / tower); Hydrogen regeneration solution: life extended to 26 months, annual cost savings of ¥2.4 million; Safety record: Online hydrogen concentration monitoring + emergency shut-off valve design, 18 months of continuous operation with zero accidents.

[0087] The above-mentioned technical solution of the present invention is like a "molecular scalpel" that gives the amine protective layer—precisely removing oxidative lesions under the mild condition of 80°C, completely subverting the traditional "brutal debridement" mode of high-temperature steam regeneration.

[0088] In another technical solution, in step 4), the discharged purge gas undergoes staged treatment via a vortex tube energy separator: A high-pressure gas-driven pneumatic motor with a pressure of 0.7 MPa recovers kinetic energy and is directly coupled to the compressor main shaft; 0.3 MPa low-pressure gas is returned to the dehumidification system to regenerate activated alumina; The cold end temperature of the separator drops to -15°C, which is used to pre-cool the air entering the dehumidifier.

[0089] In the above technical solution, the first step: integration of the vortex tube energy separation system: 1. Customized equipment installation: A three-stage vortex tube separator is connected in series in the purge exhaust gas outlet pipeline, with a single-stage processing capacity of 600 cubic meters per hour, using silicon nitride ceramic nozzles (erosion resistance life > 20,000 hours). The high-pressure stage outlet (0.7 MPa) is connected to a radial piston pneumatic motor, and the output shaft directly drives the compressor main shaft through a magnetic coupling. 2. Energy circulation path construction: The low-pressure stage outlet (0.3 MPa) gas is connected to the dehumidification tower regeneration pipeline, counter-currently flushing the activated alumina desiccant. The cold end outlet (-15℃) is led to the inlet precooler through an insulated pipeline, where it undergoes counter-current heat exchange with the fresh purge gas.

[0090] Step 2: Energy Efficiency Optimization Verification: 1. Dynamic Load Test: On a 2000 cubic meters per hour waste gas treatment unit: the pneumatic motor output power is 45 kW, compensating for 40% of the compressor input power (actual external power supply decreased from 112 kW to 67 kW). The precooler reduced the inlet air temperature from 30℃ to 8℃, and the dehumidifier load decreased by 28%. 2. Chain Energy Saving Effect: Dehumidifier regeneration gas consumption decreased by 33%, saving 360,000 yuan in nitrogen purchase costs annually. The system's total power consumption curve shows that the power consumption per ton of carbon dioxide capture stabilized at 68 kWh (a 39% decrease compared to the original system).

[0091] Comparison with the closest existing technology: Existing technical defects: 1. Mechanical complexity and efficiency loss: Using a steam turbine to recover purge gas pressure energy: the energy conversion chain is lengthy: pressure energy to mechanical energy to electrical energy to mechanical energy (overall efficiency <35%); measured data: the turbine output power is 35 kW, but the net power saving after grid connection and inverter losses is only 22 kW; maintenance costs: high-speed bearings are replaced every quarter, with annual maintenance costs exceeding 120,000 yuan; 2. Short-sighted design for cold energy waste: low-pressure exhaust gas is directly emitted: -15℃ cold energy is absorbed by the workshop environment (annual wasted cold energy is equivalent to 180 MWh); the dehumidifier operates at full load, and the proportion of regeneration power consumption rises to 41% of the total system energy consumption.

[0092] This invention features the following innovative breakthroughs: 1. Three-stage energy utilization: 0.7MPa high-pressure gas – direct drive of pneumatic motor – compressor power consumption reduced by 40%; 0.3MPa medium-pressure gas – desiccant regeneration – nitrogen saving of 33%; -15℃ cold air – intake pre-cooling – dehumidification energy consumption reduced by 28%. 2. Revolutionary zero-conversion efficiency: In terms of pressure energy recovery, existing technologies convert mechanical energy to electrical energy (22% loss), while this invention converts mechanical energy to mechanical energy (<8% loss); in terms of cold energy utilization, existing technologies do not utilize it; this invention reduces cooling load by 28%; in terms of system complexity, existing technologies require frequency converters and grid-connected equipment; this invention uses pure mechanical direct connection with no electrical conversion.

[0093] Energy efficiency comparison (data source: 2000 m³ of steel plant) 3 / h pilot plant 720 hours continuous operation average, calibrated using 0.5 precision electricity meter): Among the energy consumption indicators, the electricity consumption per ton of CO2 (kWh) is 112 in the existing technology system and 68 in the present invention system, a reduction of 39%; nitrogen consumption (m 3 The existing technology system consumes 52 kWh / t CO2, while the present invention system consumes 35 kWh / t, a reduction of 33%; the dehumidifier power consumption (kWh / t) is 28 kWh / t, while the present invention system consumes 20 kWh / t, a reduction of 28%.

[0094] The technical solution described above is like equipping a carbon capture system with a "perpetual motion" energy circulator. This invention uses the physical magic of vortex tubes to achieve the direct transfer of pressure energy and cold energy. The -15°C cold air is no longer useless waste, but the cold heart driving the energy-saving chain; the 0.7 MPa airflow impact no longer needs a tortuous power generation journey, but instead completes precise feedback to the compressor through a magnetic coupling.

[0095] Although the technical solutions of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for temperature-swing adsorption and capture of carbon dioxide in industrial waste gas mediated by a metal-organic framework material, characterized in that, Includes the following steps: 1) Industrial waste gas containing carbon dioxide, water vapor and acidic impurities is passed into an adsorption tower filled with a hydrophobic metal-organic framework adsorbent. The hydrophobic metal-organic framework adsorbent is formed by the self-assembly of zirconium-based metal clusters and fluorinated carboxylic acid ligands. The adsorption tower adopts a double-layer adsorption bed structure, with the upper layer being an acidic gas capture layer and the lower layer being a hydrophobic metal-organic framework adsorbent layer. The acidic gas capture layer is composed of honeycomb ceramics loaded with amine-functionalized mesoporous alumina. 2) When the adsorbent reaches the preset adsorption saturation threshold, stop the flow of waste gas and inject low-grade industrial waste heat medium with a temperature below 60℃ into the adsorption tower so that the adsorption bed is uniformly heated to the desorption temperature range of 110-130℃ within 5 minutes. 3) Maintain the desorption temperature to desorb carbon dioxide and collect high-purity carbon dioxide gas; 4) The adsorption bed is cooled to an adsorption temperature of 30-50℃ within 3 minutes by using inert purge gas that has been pretreated by dehumidification, thus completing a single temperature-switching adsorption cycle.

2. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 1, characterized in that, In step 1), the preparation method of the hydrophobic metal-organic framework adsorbent includes: Preparation of precursor solution: Zirconium tetrachloride and 2,3,5,6-tetrafluoroterephthalic acid were added to N,N-dimethylformamide and sonicated for 10 min until completely dissolved. Glacial acetic acid was added as a modifier to obtain a mixture. Hydrothermal synthesis: The mixture was transferred to a polytetrafluoroethylene-lined reactor and reacted at a constant temperature of 120°C for 24 hours; then naturally cooled to room temperature. Post-treatment activation: The solid white precipitate was collected by centrifugation, washed three times with N,N-dimethylformamide, extracted with methanol by Soxhlet extraction for 24 h, and activated under vacuum at 150℃ for 12 h.

3. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 1, characterized in that, In step 1), the specific preparation method of the acid gas trapping layer includes: Pretreatment of honeycomb ceramic substrate: Cordierite honeycomb ceramic is selected, treated in air atmosphere at 600℃ for 3h to remove organic impurities, immersed in 10% nitric acid solution and ultrasonically vibrated for 30min, rinsed with deionized water until neutral, and dried at 120℃ for later use. Preparation of γ-alumina coating: Boehmite was dispersed in nitric acid aqueous solution, and carboxymethyl cellulose was added as a binder. The mixture was ball-milled for 24 h to form a stable suspension. The suspension was then placed in a vacuum chamber and evacuated to a negative pressure of 0.01 bar. The coating solution was injected and maintained for 20 min. The suspension was then air-dried at room temperature for 12 h, cured at 80 °C for 6 h, and calcined at 550 °C for 4 h to form a γ-Al2O3 crystalline phase layer. The dip-coating-calcination process was repeated 3 times to obtain a uniform coating of 150 micrometers. Amine functionalization loading: Prepare a 30 wt% diethylenetriamine ethanol solution, immerse the coating in it, and gently shake at 60℃ for 6 h; transfer to a vacuum reactor, maintain a negative pressure of 0.1 bar for 40 min, drain the residual liquid, and place in a nitrogen atmosphere for stepwise temperature increase curing: nitrogen flow rate is 5 m / s. 3 At a flow rate of 8 m / h, the temperature is raised to 80℃ within 1 hour, with a nitrogen flow rate of 8 m / h. 3 At a flow rate of 10 m / h, the temperature is increased to 100℃ within 1 hour, and the nitrogen flow rate is 10 m / h. 3 At a temperature of / h, the temperature is increased to 120℃ within 2 hours, forming a chemically bonded amine layer.

4. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 2, characterized in that, In the preparation of the precursor solution, before adding glacial acetic acid, the solution is sonicated for 10 min until completely dissolved, and then the following steps are taken: add 0.8-1.2% of zirconium tetrachloride in polyethylene glycol diacrylate and continue sonicating for 10 min.

5. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 4, characterized in that, The addition of 0.8-1.2% zirconium tetrachloride in polyethylene glycol diacrylate further includes: 1%-3% zirconium tetrachloride in mesoporous titanium dioxide nanoparticles, wherein the particle size of the mesoporous titanium dioxide nanoparticles is 10-20 nm.

6. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 1, characterized in that, In step 1), hydrophobic thermally conductive fins are uniformly distributed within the hydrophobic metal-organic framework adsorbent layer. These fins are made of polytetrafluoroethylene and expanded graphite composites, and the fin surfaces are modified with perfluorooctyltriethoxysilane, satisfying the following conditions: The fin height is 20%-30% of the thickness of the hydrophobic metal-organic framework adsorbent layer; The spacing between adjacent fins is 8-12 mm; Fin tilt angle 20-30 degrees.

7. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 1, characterized in that, The outer wall of the adsorption tower is covered with a phase change temperature control interlayer, which is composed of microencapsulated tetradecane and expanded graphite, with a phase change temperature of 115℃, and satisfies the following: The thickness of the phase change temperature control jacket is 3%-5% of the adsorption tower diameter; Microcapsule particle size 10-50 μm; Graphite accounts for 30%-40% of the total mass.

8. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 7, characterized in that, The exhaust gas inlet and carbon dioxide outlet pipes of the adsorption tower are equipped with three-way plug valves. The rotor flow channel of the three-way plug valve has a 120-degree Y-shaped structure, and the rotation phase of the valve core is linked to the adsorption saturation signal to ensure: The rotor switching action is completed within 0.2 seconds; The overlap angle between the old and new tower flow channels is less than 5 degrees; The inner wall of the three-way plug valve is coated with polytetrafluoroethylene propylene.

9. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 3, characterized in that, The steps following the amino-functionalized loading step include: A nitrogen-hydrogen mixture with a dew point below -40°C is introduced into the chemically bonded amine layer in the reverse direction. The hydrogen accounts for 5% of the volume, the temperature is maintained at 80°C, the flow rate is 0.5 m / s, and the process is continued for 10 min. Then, the process is switched to the waste gas adsorption process.

10. The method for temperature-switching adsorption and capture of carbon dioxide in industrial waste gas mediated by metal-organic framework materials as described in claim 1, characterized in that, In step 4), the discharged purge gas undergoes staged treatment via a vortex tube energy separator: A high-pressure gas-driven pneumatic motor with a pressure of 0.7 MPa recovers kinetic energy and is directly coupled to the compressor main shaft; 0.3 MPa low-pressure gas is returned to the dehumidification system to regenerate activated alumina; The cold end temperature of the separator drops to -15°C, which is used to pre-cool the air entering the dehumidifier.