CO2 desorption packing, method for preparing the same and use thereof

Abstract

This invention provides a CO2 desorption packing material, its preparation method, and its applications. The CO2 desorption packing material includes a substrate and a composite carbon layer supported on the surface of the substrate. The substrate comprises a metallic material, the surface of which is capable of leaching metallic elements to form metal salts and / or metal complexes, thereby dispersing the metallic elements in the composite carbon layer. Furthermore, the composite carbon layer also contains nitrogen elements, which can form active sites for doped metal and nitrogen atoms with the metallic elements. In this CO2 desorption packing material, metallic elements are tracely leached from the substrate and dispersed in the composite carbon layer. The metallic elements and nitrogen elements obtained from the pyrolysis of a nitrogen-containing precursor form metal / nitrogen-carbon active sites, allowing the metallic elements and nitrogen elements to exert a better synergistic effect, resulting in strong stability and catalytic activity.

Description

Technical Field

[0001] This invention relates to a CO2 desorption packing material, its preparation method and application, belonging to the fields of solid waste disposal and greenhouse gas emission reduction, and is particularly applicable to the field of CO2 desorption technology. Background Technology

[0002] Carbon capture, utilization, and storage (CCUS) is a key supporting technology for global environmental protection. The CO2 desorption process, as the core link between carbon capture and subsequent utilization and storage, directly determines the operational efficiency and economics of the entire CCUS system. Currently, this process generally suffers from high energy barriers in CO2 desorption reactions and high energy consumption for absorbent regeneration, becoming one of the key bottlenecks restricting the large-scale promotion of CCUS technology. In industrial desorption processes, the desorption tower is the core equipment for realizing CO2 desorption and absorbent regeneration. The packing material inside the tower, as the core internal component for gas-liquid two-phase contact mass transfer, directly affects desorption efficiency, system energy consumption, and operational stability.

[0003] Currently, commonly used packing materials in CO2 desorption mainly include stainless steel, ceramics, and activated carbon. Among them, stainless steel packing is the most widely used in industrial projects due to its high mechanical strength, good thermal conductivity, and excellent corrosion resistance. However, conventional commercial stainless steel packing only serves as a basic gas-liquid mass transfer medium and does not possess intrinsic catalytic activity. It cannot lower the reaction energy barrier of CO2 desorption through catalysis, making it difficult to effectively reduce regeneration energy consumption and fundamentally solve the industry problem of high energy consumption in the desorption process.

[0004] To improve desorption efficiency and reduce energy consumption, existing catalytic desorption technologies often add metal-based catalysts (such as Fe, Ni, and Co) to the desorption tower to accelerate the reaction. However, these catalysts are expensive and complex metal powders that require multiple complex processes, resulting in high costs. Furthermore, they are prone to detachment under long-term gas-liquid erosion and high-temperature desorption conditions, leading to catalytic performance degradation. In addition, the added metal powder catalysts are mostly single or binary metals, exhibiting limited catalytic activity and making them difficult to adapt to complex desorption reaction systems.

[0005] Reference 1 discloses a supported catalyst, its preparation method, and its application. This supported catalyst requires support on a substrate, resulting in complex preparation processes, high costs, and a tendency for catalyst detachment. Reference 2 discloses the application of a zirconium hydrogen phosphate catalyst in carbon dioxide desorption. This zirconium hydrogen phosphate catalyst uses zirconium hydrogen phosphate as the active component, relies on the addition of Zr metal powder for preparation, and exhibits limited catalytic activity.

[0006] The large-scale accumulation and incineration of waste plastics (such as polyethylene, polypropylene, and polystyrene) leads to resource waste and environmental pollution. The resource utilization of waste plastics, combined with CO2 capture technology, is a research hotspot. Existing waste plastic modification filler technologies mostly use a single nitrogen-free plastic as a carbon source, which cannot form nitrogen-doped active sites and fails to achieve precise micro-excitation of intrinsic multi-metals on stainless steel substrates, making it difficult to balance catalytic activity and substrate mechanical strength.

[0007] Reference 3 discloses a method for preparing a monodisperse transition metal-nitrogen-carbon catalyst from waste plastics and its application. This catalyst utilizes waste polyethylene and polypropylene to prepare carbon-based materials, relies on an external nitrogen source, and cannot be used for CO2 capture technology. Reference 4 discloses a method for preparing MOF materials using waste PET and stainless steel pickling wastewater and its application. This method prepares modified materials from waste plastics, relies on a high-energy-consuming hydrothermal process to prepare the modified materials, and the MOF materials are mainly used for adsorption and other functions.

[0008] Existing stainless steel filler modification technologies mostly focus on improving surface roughness to enhance gas-liquid contact area. Meanwhile, existing acid etching processes often use a single strong acid, which only improves roughness for stainless steel surface treatment without contributing to the leaching of metals to build a catalyst. This can easily lead to excessive metal leaching, substrate damage, or the extraction of only one type of metal with uncontrollable content, resulting in resource waste and technological bottlenecks. Reference 5 discloses a stainless steel workpiece based on nano-injection molding and its surface treatment method. This method uses a single strong acid to etch the stainless steel filler, only improving surface roughness without involving the construction of catalytic functions. Reference 6 discloses a method for modifying superhydrophilic stainless steel fillers. This method performs surface hydrophilic modification on the stainless steel filler, but it lacks catalytic potential and still requires the use of an external catalyst.

[0009] Therefore, developing a CO2 desorption packing material that eliminates the need for expensive and complex external metal powder catalysts, and which can not only utilize nitrogen-containing waste plastics to construct highly efficient active sites, but also achieve multi-metal trace leaching, has become an urgent technical problem to be solved.

[0010] References:

[0011] Reference 1: CN119500133A

[0012] Reference 2: CN120242681A

[0013] Reference 3: CN121082314A

[0014] Reference 4: CN115960366A

[0015] Reference 5: CN120438246A

[0016] Reference 6: CN117418234A Summary of the Invention

[0017] The problem the invention aims to solve

[0018] In view of the technical problems existing in the prior art, such as: insufficient catalytic performance of CO2 desorption packing materials, complex catalyst loading processes, weak interfacial bonding, low resource utilization rate of waste plastics, inability to accurately leach intrinsic multimetals from stainless steel, lack of nitrogen-containing active sites, and the industry's mainstream reliance on externally added expensive and complex metal powder catalysts, this invention first provides a CO2 desorption packing material. The CO2 desorption packing material of this invention can achieve multimetal micro-leaching, can utilize nitrogen-containing waste plastics to construct highly efficient active sites, and eliminates the need for externally added expensive and complex metal powder catalysts.

[0019] Solution for solving the problem

[0020] [1] A CO2 desorption packing material, comprising: a substrate and a composite carbon layer supported on the surface of the substrate; wherein,

[0021] The substrate comprises a metallic material, the surface of which is capable of leaching metallic elements to form metal salts and / or metal complexes, thereby dispersing the metallic elements within the composite carbon layer; and...

[0022] The composite carbon layer also contains nitrogen, which can form active sites for doped metal and nitrogen atoms with the metal element.

[0023] [2] According to the CO2 desorption filler described in [1] above, wherein the metal element includes one or more of Fe, Ni and Cr.

[0024] [3] According to the CO2 desorption filler described in [1] or [2] above, wherein the leaching amount of metal elements is 0.01~0.1% based on the total mass of the metal material.

[0025] [4] The CO2 desorption filler according to any one of [1]-[3] above, wherein, in the composite carbon layer, the content of metal elements is 0.5~1.0wt% and the content of nitrogen elements is 0.1~1.0wt% based on the total mass of the composite carbon layer as 100%.

[0026] [5] The CO2 desorption filler according to any one of [1]-[4] above, wherein the raw material of the composite carbon layer includes nitrogen-containing waste plastic; preferably, the nitrogen-containing waste plastic includes one or more of nylon, polyurethane, polyamide and polyimide;

[0027] More preferably, the raw material for the composite carbon layer further includes nitrogen-free waste plastics. Preferably, the nitrogen-free waste plastics are selected from one or more combinations of polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

[0028] [6] The CO2 desorption packing material according to any one of [1]-[5] above, wherein the metal material includes stainless steel material; preferably it includes one or more of 304 stainless steel, 316 stainless steel and 201 stainless steel;

[0029] The stainless steel material includes stainless steel plate or stainless steel packing. Preferably, the stainless steel packing includes one or more of spring packing, bulk packing, and structured packing.

[0030] [7] A method for preparing CO2 desorption packing material according to any one of [1]-[6] above, comprising the following steps:

[0031] A composite acid system is used to etch the substrate, causing the surface of the substrate to leach metal elements and form mixed metal salts and / or metal complexes, resulting in etch products.

[0032] The erosion products are mixed with the raw materials of the composite carbon layer and then subjected to pyrolysis and carbonization, which causes the raw materials of the composite carbon layer to be reconstructed, forming a composite carbon layer attached to the substrate, and obtaining a carbonized product containing CO2 desorption filler.

[0033] [8] According to the preparation method described in [7] above, the composite acid system includes hydrochloric acid solution, citric acid and fluoroboric acid solution; preferably, the mass ratio of hydrochloric acid solution, citric acid and fluoroboric acid solution is 4~6:2~4:1~3; more preferably, the total concentration of the composite acid system is 0.8~1.5mol / L;

[0034] The temperature of the erosion treatment is 15-30℃, and the time of the erosion treatment is 20-80 minutes.

[0035] [9] According to the preparation method described in [7] or [8] above, the mass ratio of the raw material of the composite carbon layer to the erosion product is 1:5~20;

[0036] The pyrolysis carbonization includes pyrolysis carbonization by programmed temperature control; preferably, the programmed temperature control includes heating to 90-110°C at a rate of 5-10°C / min and holding for 30-60 min; then heating to 200-220°C at a rate of 3-5°C / min and holding for 20-40 min; finally, in a vacuum environment, heating to 800-1000°C at a rate of 5-10°C / min and holding for 120-240 min.

[0037]

[10] A method for using the CO2 desorption packing material according to any one of [1]-[6] above to catalyze CO2 desorption.

[0038] The effects of the invention

[0039] The CO2 desorption packing of the present invention allows metal elements to leach out in trace amounts from the substrate and disperse in the composite carbon layer. The metal elements and nitrogen elements obtained from the pyrolysis of nitrogen-containing precursors form metal / nitrogen-carbon active sites, which enables the metal elements and nitrogen elements to exert a better synergistic effect and have strong stability and catalytic activity.

[0040] Furthermore, the preparation method of the CO2 desorption filler of the present invention is simple in process, the raw materials are readily available, no complicated catalyst preparation and loading steps are required, and conventional substrates are used; waste plastics (nitrogen-containing waste plastics and optional nitrogen-free waste plastics) are widely available and inexpensive; the composite acid system is readily available and mild and controllable.

[0041] Furthermore, the CO2 desorption packing of the present invention has good heat and mass transfer efficiency. Relying on the high thermal conductivity of the metal substrate and the enhanced heat transfer effect of the composite carbon layer, it can be directly used in existing CO2 capture and desorption devices. Compared with conventional stainless steel packing, the carbon capture cost is significantly reduced. At the same time, the packing has excellent mechanical strength, has various forms, and can be adapted to various industrial desorption tower specifications. Attached Figure Description

[0042] Figure 1 The diagram shows the structure of the CO2 desorption packing material of the present invention; wherein, 1: substrate, 2: composite carbon layer, 3: active site.

[0043] Figure 2 A flowchart illustrating the preparation method of the present invention is shown;

[0044] Figure 3 This image shows a comparison between the CO2 desorption packing material prepared in Example 1 of the present invention and ordinary stainless steel packing material;

[0045] Figure 4 The image shows a comparison of scanning electron microscope (SEM) images of the CO2 desorption packing material prepared in Example 1 of the present invention and ordinary stainless steel packing material.

[0046] Figure 5 The Raman curve of the CO2 desorption packing material prepared in Example 1 of the present invention is shown.

[0047] Figure 6 This diagram shows a comparison of the intermittent CO2 desorption reaction performance of Example 1 of the present invention and ordinary stainless steel packing.

[0048] Figure 7 The diagram shows a comparison of the CO2 desorption rates at different temperatures between Example 1 of the present invention and ordinary stainless steel packing.

[0049] Figure 8 The diagram shows the activation energy curves of the reaction between Example 1 of the present invention and ordinary stainless steel packing. Detailed Implementation

[0050] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0051] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0052] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0053] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0054] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0055] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0056] <First Aspect>

[0057] like Figure 1 As shown, a first aspect of the present invention provides a CO2 desorption packing material, comprising: a substrate 1 and a composite carbon layer 2 loaded on the surface of the substrate 1; wherein,

[0058] The substrate 1 comprises a metallic material, the surface of which is capable of leaching metallic elements to form metal salts and / or metal complexes, thereby dispersing the metallic elements in the composite carbon layer 2; and...

[0059] The composite carbon layer 2 also contains nitrogen, which can form active sites 3 for doped metal and nitrogen atoms with the metal element.

[0060] In the CO2 desorption filler of the present invention, metal elements are leached out in trace amounts from the substrate 1 and dispersed in the composite carbon layer 2. The metal elements and nitrogen elements obtained by pyrolysis of nitrogen-containing precursors form active sites 3 of doped metal and nitrogen atoms, namely metal / nitrogen-carbon active sites 3, which enable the metal elements and nitrogen elements to play a better role and have strong stability and catalytic activity.

[0061] The CO2 desorption packing material of this invention can circulate stably in a flue gas carbon capture device. It does not alter the gas-liquid mass transfer balance, and there is no risk of blockage in the transmission pipeline, thus greatly improving system stability.

[0062] base

[0063] This invention obtains a CO2 desorption filler by using a substrate 1. The surface of the metallic material of this invention is capable of leaching metallic elements to form metal salts and / or metal complexes.

[0064] In some specific embodiments, the metallic element includes one or more combinations of Fe, Ni, and Cr, preferably including Fe, Ni, and Cr to form a multi-metallic element. Specifically, the leaching amount of the metallic element is 0.01~0.1% based on the total mass of the metallic material.

[0065] In some specific embodiments, the metal material includes stainless steel. Specifically, the metal material may include one or more of 304 stainless steel, 316 stainless steel, and 201 stainless steel.

[0066] Specifically, the stainless steel material includes stainless steel plate or stainless steel packing. Preferably, the stainless steel packing includes one or more of spring packing, bulk packing, and structured packing.

[0067] Generally speaking, random packing, also known as bulk packing, refers to packing that is mainly randomly packed. This type of packing consists of granular materials with a certain shape and is also called granular packing. Generally, random packing can be classified into three types based on its shape: ring packing, saddle packing, and metal saddle ring packing. Specifically, ring packing can include Raschig ring packing, Pall ring packing, and stepped ring packing; saddle packing can include arc saddle packing, rectangular saddle packing, and improved rectangular saddle packing.

[0068] Structured packing, also known as structured corrugated packing, addresses the issue of random gas-liquid flow paths in haphazardly packed towers. While this is possible, achieving uniform packing throughout the tower can lead to channeling and other undesirable phenomena, reducing tower efficiency. Structured packing, on the other hand, is a type of packing that is neatly and regularly stacked in a uniform geometric pattern within the tower. This artificially defines the gas-liquid flow paths within the packing layer, reducing channeling and wall flow, significantly lowering pressure drop, and improving heat and mass transfer efficiency.

[0069] Composite carbon layer

[0070] In this invention, metal elements are leached from the surface of a metal material, and after carbonization, the metal elements are dispersed in the composite carbon layer 2 by forming metal salts and / or metal complexes. The composite carbon layer 2 of this invention also contains nitrogen elements, which can form active sites 3 of doped metal and nitrogen atoms with the metal elements, i.e., metal / nitrogen-carbon active sites 3.

[0071] The CO2 desorption packing material prepared by this invention has metal elements that are leached out in trace amounts from the substrate 1 and dispersed in the composite carbon layer 2. The metal elements and nitrogen elements form metal / nitrogen-carbon active sites 3, which allows the metal elements and nitrogen elements to play a better role and has strong stability and catalytic activity.

[0072] In this invention, the thickness of the composite carbon layer 2 is 0.5~50 μm. When the thickness of the composite carbon layer 2 is 0.5~50 μm, the function of the composite carbon layer 2 can be more effectively exerted.

[0073] Furthermore, in the composite carbon layer 2, based on the total mass of the composite carbon layer 2 (100%), the content of metal elements is 0.5~1.0 wt%, and the content of nitrogen elements is 0.1~1.0 wt%. When the content of metal elements is 0.5~1.0 wt%, and the content of nitrogen elements is 0.1~1.0 wt%, it is more conducive to the formation of metal / nitrogen-carbon active sites 3 with nitrogen elements, resulting in stronger stability and catalytic activity.

[0074] In some specific implementations, the present invention uses waste plastics as the raw material for the composite carbon layer 2; the present invention can use waste plastics as the raw material for the composite carbon layer 2, as waste plastics are widely available, inexpensive, and can form the required carbon layer.

[0075] Specifically, in order to contain nitrogen in the composite carbon layer 2, the raw material of the composite carbon layer 2 includes nitrogen-containing waste plastics. Preferably, the nitrogen-containing waste plastics include one or more combinations of nylon, polyurethane, polyamide, and polyimide.

[0076] Furthermore, the raw material for the composite carbon layer 2 may also include nitrogen-free waste plastics. Preferably, the nitrogen-free waste plastics are selected from one or more combinations of polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

[0077] Specifically, the mass ratio of nitrogen-containing waste plastic to nitrogen-free waste plastic can be 1:0.5~2. When the mass ratio of nitrogen-containing waste plastic to nitrogen-free waste plastic is 1:0.5~2, it is more conducive to obtaining the desired carbon layer.

[0078] <Second aspect>

[0079] A second aspect of the present invention provides a method for preparing a CO2 desorption packing material according to the first aspect of the present invention, comprising the following steps:

[0080] A composite acid system is used to etch the substrate 1, causing the surface of the substrate 1 to leach metal elements and form mixed metal salts and / or metal complexes, thus obtaining the etching product;

[0081] The erosion product is mixed with the raw material of the composite carbon layer 2 and then subjected to pyrolysis carbonization, so that the raw material of the composite carbon layer 2 is reconstructed to form a composite carbon layer 2 attached to the substrate 1, thereby obtaining a carbonized product containing CO2 desorption filler.

[0082] The CO2 desorption packing material of the present invention has a simple preparation process, uses inexpensive and readily available raw materials, does not require complex catalyst preparation and loading steps, can use conventional industrial metal materials as substrate 1, and the composite acid system is easy to obtain and mild and controllable; waste plastics (nitrogen-containing waste plastics and optional nitrogen-free waste plastics) are widely available and inexpensive.

[0083] Specifically, it can be done according to Figure 2 The preparation process of the present invention will be described in detail below.

[0084] Preprocessing

[0085] This invention allows for the pretreatment of substrate 1. In some specific embodiments, the pretreatment includes conventional cleaning and drying steps. The cleaning can be performed using a polar solvent. This invention does not specifically limit the polar solvent; it can be water and / or alcohol solvents. Specifically, water can be used to rinse away surface oil and impurities, followed by ultrasonic cleaning using an alcohol solvent. This invention does not specifically limit the alcohol solvent; it can be ethanol, etc.

[0086] Furthermore, the present invention does not impose any particular limitation on the drying process; specifically, drying can be carried out at a temperature of 80~120°C. Specifically, the drying time can be 1~3 hours.

[0087] Erosion treatment

[0088] The present invention employs a composite acid system to etch substrate 1, thereby leaching metal elements from the surface of substrate 1 and forming mixed metal salts and / or metal complexes to obtain etch products.

[0089] In some specific embodiments, the composite acid system includes hydrochloric acid solution, citric acid, and fluoroboric acid solution; wherein hydrochloric acid serves as the main etchant, providing H... + This process dissolves the oxide film and base metal on the stainless steel surface, achieving initial leaching of metal elements such as Fe, Ni, and Cr. Citric acid acts as a complexing agent, forming stable, soluble complexes with the leached metal ions to prevent redeposition of metal ions onto the substrate surface. Simultaneously, it regulates the metal leaching rate, avoiding excessive corrosion. Fluoroboric acid, acting as both a corrosion inhibitor and surfactant, facilitates the leaching of metals through the application of F... - It forms a passivation film on the metal surface to inhibit deep corrosion, while improving the wettability of acid on the stainless steel surface and achieving uniform erosion.

[0090] In this invention, hydrochloric acid and fluoroboric acid exist in solution form. The concentrations of hydrochloric acid and fluoroboric acid are not particularly limited in this invention. Specifically, the hydrochloric acid solution can be an aqueous solution with a mass concentration of 30-40%. The fluoroboric acid solution can be an aqueous solution with a mass concentration of 35-45%.

[0091] Preferably, the mass ratio of hydrochloric acid solution, citric acid and fluoroboric acid solution is 4~6:2~4:1~3; more preferably, the total concentration of the composite acid system is 0.8~1.5 mol / L.

[0092] In some specific implementations, the etching treatment temperature is 15~30℃, and the etching treatment time is 20~80 minutes. Generally speaking, etching treatment can be carried out stably at room temperature.

[0093] Furthermore, to improve the erosion process, stirring and / or ultrasonication can be used. Specifically, magnetic stirring can be employed to enhance the erosion process. The stirring speed can be 90-150 r / min.

[0094] Further, after etching, cleaning and / or drying are performed to obtain the etched product. Similar to the pretreatment cleaning, polar solvents can be used, for example, repeated rinsing with water until the pH reaches 6-8. Drying can also be carried out at a temperature of 80-120°C. Specifically, the drying time can be 1-3 hours.

[0095] Through etching, a nanoscale rough surface is formed on the surface of substrate 1, and trace amounts of metal elements such as Fe, Ni, and Cr are leached out to form mixed metal salts such as FeCl2, NiCl2, and CrCl3. Furthermore, citric acid can form complexes with some metal ions and uniformly adhere to the surface of substrate 1.

[0096] Pyrolysis carbonization

[0097] The erosion product is mixed with the raw material of the composite carbon layer 2 and then subjected to pyrolysis carbonization to reconstruct the raw material of the composite carbon layer 2, forming a composite carbon layer 2 attached to the substrate 1, and obtaining a carbonized product containing CO2 desorption filler.

[0098] Specifically, the mass ratio of the raw material to the erosion product in the composite carbon layer 2 can be 1:5 to 20. When the mass ratio of the raw material to the erosion product in the composite carbon layer 2 is 1:5 to 20, it is beneficial to obtain the desired CO2 desorption filler.

[0099] In some specific implementations, the pyrolytic carbonization includes pyrolytic carbonization performed by programmed temperature control; specifically, the pyrolytic carbonization may be carried out under vacuum conditions.

[0100] Preferably, the programmed temperature control includes increasing the temperature at 5~10℃ / min to 90~110℃ and holding for 30~60min; then increasing the temperature at 3~5℃ / min to 200~220℃ and holding for 20~40min; and finally increasing the temperature at 5~10℃ / min to 800~1000℃ and holding for 120~240min.

[0101] In this invention, the first stage (90~110℃ heat preservation) is the drying and dehydration stage, which removes the moisture adsorbed on the surface of the raw materials and substrate 1 to prevent the rapid vaporization of moisture at high temperature from causing the carbon layer to crack and fall off; the second stage (200~220℃ heat preservation) is the plastic melting and pre-decomposition stage, which allows the waste plastic to be fully melted and evenly spread on the surface of substrate 1, while initial decomposition occurs, releasing small molecule volatile substances, providing reaction sites for subsequent carbonization to form a uniform carbon layer; the third stage (800~1000℃ heat preservation) is the high-temperature carbonization and active site 3 formation stage, where the waste plastic undergoes deep carbonization to form a graphitized carbon layer, and at the same time, the leached metal elements and nitrogen atoms produced by the decomposition of nitrogen-containing plastics undergo coordination reactions to form stable metal / nitrogen carbon (MNC) active sites 3.

[0102] Finally, the carbonized product undergoes post-treatment to obtain the CO2 desorption packing material. The post-treatment is the same as or similar to the pre-treatment and may include cleaning and / or drying steps. Similar to the cleaning in pre-treatment, polar solvents can be used for cleaning, such as rinsing with water to remove residual impurities and unreacted metal salts from the surface. Drying can also be carried out at a temperature of 80–120°C. Specifically, the drying time can be 1–3 hours.

[0103] <Third aspect>

[0104] A third aspect of the present invention provides a method for using the CO2 desorption packing material according to the first aspect of the present invention for catalytic CO2 desorption.

[0105] The CO2 desorption packing of the present invention has good heat and mass transfer efficiency. Relying on the high thermal conductivity of the substrate 1 and the enhanced heat transfer effect of the composite carbon layer 2, it can be directly used in existing CO2 capture and desorption devices. Compared with conventional stainless steel packing, it can increase the CO2 desorption rate by about 30-60%, reduce desorption energy consumption by about 20-40%, and significantly reduce carbon capture cost. At the same time, the packing has excellent mechanical strength, has various forms, and can be adapted to various industrial desorption tower specifications.

[0106] Example

[0107] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0108] Example 1

[0109] Step 1: Pretreatment of stainless steel substrate

[0110] Select 304 stainless steel Pall rings (specifications: outer diameter 50mm, height 50mm, wall thickness 1.5mm, e.g.) Figure 3 (As shown in the left figure) as the substrate, rinse the surface oil and impurities with deionized water, then ultrasonically clean with anhydrous ethanol for 20 minutes, and dry in an oven at 105℃ for 2 hours for later use.

[0111] Step 2: Composite acid and mild etching treatment

[0112] A hydrochloric acid-citric acid-fluoroboric acid composite acid system (37% hydrochloric acid, anhydrous citric acid, and 40% fluoroboric acid in a mass ratio of 5:3:2) was prepared, with the total concentration of the composite acid system controlled at 1.0 mol / L. The pretreated stainless steel packing ring was immersed in the composite acid solution and gently etched at 25℃ for 40 min, with magnetic stirring at a rate of 120 r / min during the etching process. After etching, the stainless steel packing ring was removed, repeatedly rinsed with deionized water until the pH reached 7, and then dried in a 105℃ oven for 2 h for later use. At this point, a nanoscale rough surface was formed on the stainless steel surface, and trace amounts of metal elements such as Fe, Ni, and Cr were leached (leaching amount accounting for 0.05% of the total mass of the substrate). Mixed metal salts such as FeCl2, NiCl2, and CrCl3 were formed on the surface of the stainless steel Pall ring, and citric acid formed complexes with some metal ions, uniformly adhering to the surface, thus obtaining the etching product.

[0113] Step 3: Plastic mixing and pyrolysis carbonization

[0114] Waste nylon 66 and waste polypropylene were mixed at a mass ratio of 1:1 by stirring. The mixed plastic powder and the erosion product were then mixed evenly at a mass ratio of 1:10 and placed in a tube furnace. After vacuuming, the furnace was subjected to programmed temperature-controlled pyrolysis carbonization: the temperature was increased to 100℃ at a heating rate of 8℃ / min and held for 45 min; then increased to 210℃ at a heating rate of 4℃ / min and held for 30 min; finally, the temperature was increased to 900℃ at a heating rate of 8℃ / min and held for 180 min. After the pyrolysis carbonization was completed, the furnace was cooled to room temperature to obtain the carbonized product.

[0115] Step 4: Post-processing

[0116] The carbonized product was removed, and the surface was rinsed with deionized water to remove residual impurities and unreacted metal salts. It was then dried in a 105℃ oven for 2 hours to obtain the CO2 desorption filler. Figure 3 As shown in the right figure.

[0117] Example 2

[0118] Step 1: Pretreatment of stainless steel substrate

[0119] Select a 316 stainless steel Pall ring (specifications: outer diameter 60mm, height 40mm, wall thickness 2.0mm) as the base, rinse the surface oil and impurities with deionized water, then ultrasonically clean it with anhydrous ethanol for 15 minutes, and dry it in a 105℃ oven for 2 hours for later use.

[0120] Step 2: Composite acid and mild etching treatment

[0121] A hydrochloric acid-citric acid-fluoroboric acid composite acid system (37% hydrochloric acid, anhydrous citric acid, and 40% fluoroboric acid in a mass ratio of 5:3:2) was prepared, with the total concentration of the composite acid system controlled at 0.9 mol / L. Pretreated stainless steel Pall rings were immersed in the composite acid solution and gently etched at 20℃ for 50 min, with magnetic stirring at a rate of 100 r / min during the etching process. After etching, the stainless steel Pall rings were removed, repeatedly rinsed with deionized water until the pH reached 7, and then dried in a 105℃ oven for 2 h for later use. At this point, a nanoscale rough surface was formed on the stainless steel surface, and trace amounts of metal elements such as Fe, Ni, and Cr were leached (leaching amount accounting for 0.04% of the total mass of the substrate). Mixed metal salts such as FeCl2, NiCl2, and CrCl3 were formed on the surface of the stainless steel Pall rings, and citric acid formed complexes with some metal ions, uniformly adhering to the surface, thus obtaining the etching product.

[0122] Step 3: Plastic mixing and pyrolysis carbonization

[0123] Waste polyurethane and waste polyethylene were mixed at a mass ratio of 1:1.2 by stirring. The mixed plastic powder and the erosion product were then mixed evenly at a mass ratio of 1:12 and placed in a tube furnace. After vacuuming, a programmed temperature-controlled pyrolysis carbonization was performed: the temperature was increased to 100℃ at a heating rate of 6℃ / min and held for 30 min; then increased to 210℃ at a heating rate of 3℃ / min and held for 25 min; finally, the temperature was increased to 850℃ at a heating rate of 6℃ / min and held for 200 min. After the pyrolysis carbonization was completed, the furnace was cooled to room temperature to obtain the carbonized product.

[0124] Step 4: Post-processing

[0125] The carbonized product was removed, and the surface was rinsed with deionized water to remove residual impurities and unreacted metal salts. It was then dried in an oven at 105°C for 2 hours to obtain the CO2 desorption filler.

[0126] Example 3

[0127] Step 1: Pretreatment of stainless steel substrate

[0128] Select 201 stainless steel corrugated packing (specifications: corrugation height 5mm, plate thickness 0.8mm) as the base, rinse the surface oil and impurities with deionized water, then ultrasonically clean with anhydrous ethanol for 25 minutes, and dry in an oven at 105℃ for 2 hours for later use.

[0129] Step 2: Composite acid and mild etching treatment

[0130] A hydrochloric acid-citric acid-fluoroboric acid composite acid system (37% hydrochloric acid, anhydrous citric acid, and 40% fluoroboric acid in a mass ratio of 5:3:2) was prepared, with the total concentration of the composite acid system controlled at 1.2 mol / L. The pretreated stainless steel corrugated packing was immersed in the composite acid solution and gently etched at 30℃ for 30 min, with magnetic stirring at a rate of 150 r / min during the etching process. After etching, the stainless steel corrugated packing was removed, repeatedly rinsed with deionized water until the pH reached 7, and then dried in a 105℃ oven for 2 h for later use. At this point, a nanoscale rough surface was formed on the stainless steel surface, and trace amounts of metal elements such as Fe, Ni, and Cr were leached out (leaching amount accounting for 0.06% of the total mass of the substrate). Mixed metal salts such as FeCl2, NiCl2, and CrCl3 were formed on the surface of the 201 stainless steel corrugated packing, and citric acid formed complexes with some metal ions, uniformly adhering to the surface, thus obtaining the etching product.

[0131] Step 3: Plastic mixing and pyrolysis carbonization

[0132] Waste polyamide 6 and waste polystyrene were mixed at a mass ratio of 1:0.8 by stirring. The mixed plastic powder and the erosion product were then mixed evenly at a mass ratio of 1:8 and placed in a tube furnace. After vacuuming, the furnace was subjected to programmed temperature-controlled pyrolysis carbonization: the temperature was increased to 100℃ at a heating rate of 10℃ / min and held for 60 min; then increased to 210℃ at a heating rate of 5℃ / min and held for 40 min; finally, the temperature was increased to 950℃ at a heating rate of 10℃ / min and held for 150 min. After the pyrolysis carbonization was completed, the furnace was cooled to room temperature to obtain the carbonized product.

[0133] Step 4: Post-processing

[0134] The carbonized product was removed, and the surface was rinsed with deionized water to remove residual impurities and unreacted metal salts. It was then dried in an oven at 105°C for 2 hours to obtain the CO2 desorption filler.

[0135] Performance testing

[0136] 1. Thickness of the composite carbon layer

[0137] The thickness of the composite carbon layer in Examples 1-3 was measured using a thickness gauge, and the results are shown in Table 1 below.

[0138] Table 1

[0139]

[0140] 2. Element content testing

[0141] The metal and nitrogen contents of Examples 1-3 were determined using X-ray photoelectron spectroscopy (XPS). Flat, 5mm × 5mm blocks suitable for the XPS sample stage size were cut directly from the CO2 desorption packing material of Examples 1-3 using tools. These blocks were then fixed to the sample stage using double-sided conductive adhesive and placed into a vacuum chamber. X-rays were directly irradiated onto the packing surface for measurement. The results are shown in Table 2.

[0142] Table 2

[0143]

[0144] 3. Scanning electron microscopy observation

[0145] The morphology of the CO2 desorption packing material prepared in Example 1 and the ordinary stainless steel packing material (304 stainless steel packing ring) was analyzed using scanning electron microscopy (SEM). The results are as follows: Figure 4 As shown.

[0146] Depend on Figure 4 As can be seen, the surface of untreated ordinary stainless steel packing (left figure) is smooth and dense, while the surface of the CO2 desorption packing of the present invention is covered by a rough and porous composite carbon layer.

[0147] 4. Raman spectroscopy analysis

[0148] The CO2 desorption packing material prepared in Example 1 and ordinary stainless steel packing material (304 stainless steel packing rings) were tested using Raman spectroscopy, and the results are as follows: Figure 5 As shown.

[0149] Depend on Figure 5 It can be seen that ordinary stainless steel packing has no obvious characteristic peaks, while CO2 desorption packing shows a peak at 1350 cm⁻¹. -1 and 1580 cm -1 The presence of distinct carbon material characteristic D and G peaks nearby further confirms that a composite carbon layer has been successfully constructed on the surface of the stainless steel substrate.

[0150] 5. Intermittent catalytic desorption performance test

[0151] The test was conducted using a programmed temperature-increasing desorption experimental setup. Equal amounts of the CO2 desorption packing material from Example 1 and ordinary stainless steel packing (304 stainless steel packing rings) were loaded into the reactor. A CO2-saturated rich solution was injected, and heating desorption was performed under the same heating power. The changes in system temperature and CO2 desorption rate over time were recorded. The results are as follows: Figure 6 As shown.

[0152] Depend on Figure 6As can be seen, under the same heating curve, the desorption process of the ordinary stainless steel packing in Example 1 is very slow, with a peak desorption rate of only about 20 mL / min; while when using the CO2 desorption packing prepared by this invention, the peak desorption rate is significantly advanced, and the peak rate is increased to about 58 mL / min. This indicates that the composite carbon layer and metal / nitrogen-carbon active sites on the packing surface accelerate the CO2 desorption rate, exhibiting excellent catalytic desorption performance.

[0153] 6. Continuous desorption performance and long-term operational stability test

[0154] A continuous absorption-desorption pilot-scale platform consisting of an absorption tower and a desorption tower was used to study the CO2 capture and catalytic desorption characteristics under simulated actual operating conditions. Both the absorption tower and the desorption tower were filled with equal volumes of the packing material to be tested (i.e., the CO2 desorption packing material from Examples 1-3 and the corresponding ordinary stainless steel packing material). The simulated flue gas composition volume ratio was 12% CO2, 10% O2, and 78% N2, with a total flow rate of 15 L / min. A composite amine solution was used as the absorbent, with a liquid-to-gas ratio set at 2.5 L / Nm³. 3 The desorption tower operating temperature was controlled at 105℃. The desorbed CO2 flow rate was monitored and recorded in real time by a gas flow meter. The total energy consumption of the desorption process (GJ / tCO2) was calculated from the desorption heating power consumption and the total amount of desorbed CO2. After 168 hours of continuous operation, the catalytic performance decay rate was calculated, and the results are shown in Table 3.

[0155] Table 3

[0156]

[0157] As can be seen from Table 3, compared with the 304 stainless steel packing ring, the CO2 desorption packing of Example 1 has a 45% higher CO2 desorption rate, a 34% lower desorption energy consumption, and after 168 hours of continuous operation, the catalytic performance decays by less than 7%, there is no interface detachment, and the mechanical strength of the stainless steel substrate does not decrease significantly.

[0158] Compared with 316 stainless steel Pall rings, the CO2 desorption packing material in Example 2 has a 40% higher CO2 desorption rate, a 28% lower desorption energy consumption, and after 168 hours of continuous operation, the catalytic performance decays by less than 6%, the interface is tightly bonded, and the substrate mechanical strength remains good.

[0159] Compared with stainless steel corrugated packing, the CO2 desorption packing in Example 3 has a 50% higher CO2 desorption rate, a 40% lower desorption energy consumption, and after 168 hours of continuous operation, the catalytic performance decays by less than 4%, while maintaining good mechanical strength.

[0160] 7. Activation energy of desorption reaction

[0161] 5g of the CO2 desorption packing material from Example 1 and ordinary stainless steel packing (304 stainless steel packing rings) were added to the reactor at a feed rate of 5mL / min. The temperatures were set at 65℃, 70℃, 75℃, 80℃, 85℃, and 90℃. Desorption performance was tested using the method described above, and the carbon dioxide desorption rate under stable operating conditions was recorded at these six temperature points. The specific desorption rates are as follows: Figure 7 As shown. Based on the desorption rate test data at different set temperatures, the apparent activation energy of the desorption reaction was calculated by fitting the Arrhenius equation, and the results are as follows. Figure 8 As shown.

[0162] Depend on Figure 7 It can be seen that, at any temperature, the CO2 desorption packing of the present invention exhibits a superior desorption rate compared to ordinary stainless steel packing.

[0163] Depend on Figure 8 It can be seen that in the ordinary stainless steel packing system, the activation energy of the CO2 desorption reaction is as high as 56.79 kJ / mol. In contrast, when using the CO2 desorption packing prepared in this invention, the activation energy of the desorption reaction is significantly reduced to 44.42 kJ / mol, a decrease of approximately 21.8%. This demonstrates that the composite carbon layer and metal / nitrogen-carbon active sites supported on the surface of the metal packing exhibit high intrinsic catalytic activity.

[0164] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0165] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A CO2 desorption packing material, characterized in that, include: A substrate and a composite carbon layer loaded on the surface of the substrate; wherein, The substrate comprises a metallic material, the surface of which is capable of leaching metallic elements to form metal salts and / or metal complexes, thereby dispersing the metallic elements within the composite carbon layer; and... The composite carbon layer also contains nitrogen, which can form active sites for doped metal and nitrogen atoms with the metal element.

2. The CO2 desorption packing material according to claim 1, characterized in that, The metallic element includes one or more of Fe, Ni, and Cr.

3. The CO2 desorption packing material according to claim 1 or 2, characterized in that, The leaching amount of the metal element is 0.01~0.1% based on the total mass of the metal material.

4. The CO2 desorption packing material according to any one of claims 1-3, characterized in that, In the composite carbon layer, based on the total mass of the composite carbon layer as 100%, the content of metal elements is 0.5~1.0wt% and the content of nitrogen elements is 0.1~1.0wt%.

5. The CO2 desorption packing material according to any one of claims 1-4, characterized in that, The raw material for the composite carbon layer includes nitrogen-containing waste plastics; preferably, the nitrogen-containing waste plastics include one or more of nylon, polyurethane, polyamide, and polyimide. More preferably, the raw material for the composite carbon layer further includes nitrogen-free waste plastics. Preferably, the nitrogen-free waste plastics are selected from one or more combinations of polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

6. The CO2 desorption packing material according to any one of claims 1-5, characterized in that, The metal material includes stainless steel; preferably, it includes one or more of 304 stainless steel, 316 stainless steel, and 201 stainless steel. The stainless steel material includes stainless steel plate or stainless steel packing. Preferably, the stainless steel packing includes one or more of spring packing, bulk packing, and structured packing.

7. A method for preparing a CO2 desorption packing material according to any one of claims 1-6, characterized in that, Includes the following steps: A composite acid system is used to etch the substrate, causing the surface of the substrate to leach metal elements and form mixed metal salts and / or metal complexes, resulting in etch products. The erosion products are mixed with the raw materials of the composite carbon layer and then subjected to pyrolysis and carbonization, which causes the raw materials of the composite carbon layer to be reconstructed, forming a composite carbon layer attached to the surface of the substrate, and obtaining a carbonized product containing CO2 desorption filler.

8. The preparation method according to claim 7, characterized in that, The composite acid system includes hydrochloric acid solution, citric acid and fluoroboric acid solution; preferably, the mass ratio of the hydrochloric acid solution, citric acid and fluoroboric acid solution is 4~6:2~4:1~3; more preferably, the total concentration of the composite acid system is 0.8~1.5 mol / L; The temperature of the erosion treatment is 15~30℃, and the time of the erosion treatment is 20~80min.

9. The preparation method according to claim 7 or 8, characterized in that, The mass ratio of the raw material of the composite carbon layer to the erosion product is 1:5~20; The pyrolysis carbonization includes pyrolysis carbonization by programmed temperature control; preferably, the programmed temperature control includes heating to 90-110°C at a rate of 5-10°C / min and holding for 30-60 min; then heating to 200-220°C at a rate of 3-5°C / min and holding for 20-40 min; finally, in a vacuum environment, heating to 800-1000°C at a rate of 5-10°C / min and holding for 120-240 min.

10. A method for using the CO2 desorption packing material according to any one of claims 1-6 for catalytic CO2 desorption.

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