Composite VOCs concentration homogenizing agent and preparation method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING YANJIANG ACAD OF RESCOURCES & ECOLOGY SCI CO LTD
- Filing Date
- 2026-04-22
- Publication Date
- 2026-07-03
Smart Images
Figure CN122076388B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of homogenizer preparation technology, specifically to a composite VOCs concentration homogenizer and its preparation method. Background Technology
[0002] In the process of VOCs waste gas treatment, the problem of large fluctuations in VOCs concentration is often encountered. Typical scenarios include venting waste gas from reactors, large and small breathing of storage tanks, and intermittent loading and unloading waste gas. To ensure the safety and stability of subsequent treatment processes, VOCs need to be homogenized and pretreated before treating such fluctuating waste gas concentrations.
[0003] Currently, the conventional process for homogenization pretreatment involves setting up a homogenization tank and filling it with a homogenizing agent, primarily activated carbon. The core of the homogenizing agent's effect lies in its bidirectional adsorption and desorption process: adsorbing VOCs when the VOC concentration is high and desorbing the adsorbed VOCs when the VOC concentration is low. However, activated carbon, due to its high micropore content, while effectively adsorbing high-concentration VOCs, suffers from an excessively strong VOCs capture capacity. This makes it difficult for the adsorbed VOCs to desorb into low-concentration waste gas, resulting in a "one-way in, one-way out" situation. Consequently, it easily loses its homogenization effect and fails to meet actual pretreatment requirements.
[0004] Therefore, there is an urgent need to develop a homogenizer with excellent VOCs adsorption and desorption performance at room temperature and pressure, which can efficiently adsorb VOCs in high-concentration waste gas and release adsorbed VOCs in a timely manner in low-concentration waste gas, forming an effective adsorption-desorption cycle that changes with the VOCs concentration in the waste gas. Summary of the Invention
[0005] To address the aforementioned issues, this application provides a composite VOCs concentration homogenizer and its preparation method. The invention involves preparing steam-activated attapulgite clay through steam activation treatment, reacting diatomaceous earth with phosphonic acid to prepare phosphonic acid-modified diatomaceous earth, then compounding it with nano-ZrO2 and mesoporous silica to obtain modified diatomaceous earth. Subsequently, the modified diatomaceous earth is uniformly mixed with powdered activated carbon, molecular sieves, lubricants, binders, and deionized water to obtain a composite VOCs concentration homogenizer. This enhances the bidirectional adsorption and desorption performance of VOCs, constructs a stable adsorption-desorption cycle, and simultaneously improves the stability and reliability of VOCs concentration homogenization, meeting the pretreatment requirements under VOCs fluctuation scenarios.
[0006] To achieve the above objectives, this application adopts the following technical solution:
[0007] In a first aspect, this application provides a composite VOCs concentration homogenizer, comprising powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth, molecular sieve, lubricant, binder, and deionized water; wherein the steam-activated attapulgite clay is obtained by steam activation treatment of attapulgite clay; wherein the modified diatomaceous earth is obtained by compounding phosphonic acid modified diatomaceous earth, nano-ZrO2, and mesoporous silica; wherein the phosphonic acid modified diatomaceous earth is obtained by reacting diatomaceous earth with phosphonic acid.
[0008] Preferably, the mass ratio of the powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth, molecular sieve, lubricant, binder and deionized water is (20~50):(10~30):(5~25):(5~20):(0.5~5):(3~10):(30~50).
[0009] Preferably, the mass ratio of the phosphonic acid modified diatomaceous earth, nano ZrO2, and mesoporous silica is (60~80):(10~25):(10~20); and the mass ratio of the diatomaceous earth to the phosphonic acid is (5~10):1.
[0010] Preferably, the powdered activated carbon comprises powdered coal-based carbon or powdered wood-based carbon; the molecular sieve comprises any one of ZSM-5, SBA-15 and beta molecular sieves; the lubricant comprises any one of calcium stearate, zinc stearate and polyethylene wax; and the binder comprises any one of polyvinyl alcohol, hydroxymethyl cellulose and starch.
[0011] Secondly, this application provides a method for preparing a composite VOCs concentration homogenizer, comprising the following steps:
[0012] S1. The attapulgite clay is crushed and placed in a high-temperature activation furnace. Saturated steam is introduced for steam activation treatment. After cooling to room temperature, it is ground and sieved to obtain steam-activated attapulgite clay.
[0013] S2. Pulverize and sieve the diatomaceous earth, add it to deionized water and stir to disperse it, forming a diatomaceous earth suspension. Add phosphonic acid and stir to react. Cool, filter, wash until the pH is 7-8, dry, grind and sieve to obtain phosphonic acid modified diatomaceous earth.
[0014] S3. The phosphonic acid modified diatomaceous earth, nano ZrO2 and mesoporous silica are added to a high-speed mixer and mixed at high speed to obtain modified diatomaceous earth;
[0015] S4. Powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth, molecular sieve, lubricant, and binder are put into a mixer and dry-mixed to obtain a mixture.
[0016] S5. Add deionized water to the mixture, mix well, shape, dry and heat-insulate to cure, and obtain a composite VOCs concentration homogenizer.
[0017] The S1 described in this application modulates the pore structure and surface properties of attapulgite clay through high-temperature steam activation treatment. In a saturated steam atmosphere, the high temperature causes the bound water between clay mineral layers to escape rapidly, promoting the expansion and exfoliation of the layered structure. Simultaneously, steam molecules selectively etch amorphous components and organic impurities in the clay framework, clearing existing pores and creating new mesopores and micropores, forming a well-developed meso-microporous composite channel network. This process optimizes the pore size distribution of the material, enhances its diffusion and transport capabilities and physical adsorption capacity for VOCs of different molecular sizes, and lays the foundation for the subsequent construction of a hierarchical porous structure with suitable adsorption capacity.
[0018] The S2 method introduces specific adsorption sites through the surface reaction of phosphonic acid with diatomaceous earth. After pulverization and dispersion, the abundant silanol groups on the surface of diatomaceous earth are fully exposed. In an aqueous medium, phosphonic acid molecules covalently bond with silanol groups through esterification, stabilizing the grafted phosphonic acid groups on the surface of diatomaceous earth. This chemical modification transforms diatomaceous earth from an inert carrier primarily capable of physical adsorption into an active component with chemical adsorption capabilities. The phosphonic acid groups can act as Lewis base sites, selectively adsorbing polar or oxygen-containing VOCs molecules through coordination, thereby broadening the homogenizer's activity spectrum and enhancing its ability to capture specific species.
[0019] In step S3, phosphonic acid-modified diatomaceous earth, nano-ZrO2, and mesoporous silica are fed into a high-speed mixer. Under intense shearing and impact, the nano-ZrO2 particles are uniformly dispersed and partially embedded in the surface defects and pores of the diatomaceous earth and mesoporous silica. The ordered channels of the mesoporous silica provide spatial confinement for the dispersion of nanoparticles, preventing their aggregation. Phosphonic acid groups provide chemisorption sites, Lewis acid sites on the surface of nano-ZrO2 can catalyze the partial degradation of adsorbed VOCs, and mesoporous silica serves as a highly efficient VOCs molecular transport channel, synergistically enhancing the overall performance of the unit components.
[0020] The S4 process achieves primary uniform composite formation of porous adsorbent materials, molecular sieves, and molding aids through dry mechanical mixing. Powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth composite system, and molecular sieves are mechanically mixed in a mixer. The components are initially bonded by van der Waals forces, thus initially constructing a multi-level, multi-functional composite adsorbent network containing micropores (activated carbon, molecular sieves), mesopores (attapulgite clay, mesoporous silica), and chemical / catalytic sites (modified diatomaceous earth, nano-ZrO2). The addition of lubricant reduces friction between solid particles, promoting uniform dispersion; the initial dispersion of the binder prepares for the formation of a stable three-dimensional cross-linked network structure during wet mixing and molding.
[0021] The S5 process achieves final structural shaping and reinforcement of the homogenizer through wet mixing, molding, and curing. After adding deionized water to the dry mixture, water molecules lubricate and encapsulate the particles, allowing the binder to fully dissolve and spread across the surfaces and gaps of each component. During mixing and molding, binder molecules form a robust three-dimensional network framework between components through cross-linking, fixing porous adsorbent materials, molecular sieves, and other active components within it, forming a preform with specific shape and strength. Subsequent drying and heat-insulating curing processes gradually remove moisture and further condense and solidify the binder network, ultimately forming a composite VOCs concentration homogenizer with good mechanical strength, intact and interconnected internal multi-level pores. This structure ensures efficient diffusion of VOCs molecules throughout the material and achieves reversible adsorption-desorption.
[0022] Preferably, in S1, the temperature of the steam activation treatment is 300-500°C and the time is 2-4 hours.
[0023] Preferably, in S2, the temperature of the stirring reaction is 60-90°C and the time is 2-4 hours; the mesh size of the grinding and sieving is 100-200 mesh.
[0024] Preferably, in S2, the amount of deionized water added during the formation of the diatomaceous earth suspension is 30% to 40% of the total amount of deionized water added.
[0025] Preferably, in S3, the high-speed mixing speed is 3000-5000 r / min and the time is 30-60 min.
[0026] Preferably, in S4, the dry mixing speed of the mixer is 300-800 r / min and the time is 10-20 min.
[0027] Preferably, in step S5, the curing temperature is 100~150℃ and the time is 1~3h; the drying temperature is 60~100℃ and the time is 4~8h.
[0028] Preferably, in S5, the amount of deionized water added is the remaining deionized water, and the amount of deionized water added in S2 and S5 is the total deionized water.
[0029] Compared with the prior art, the beneficial effects of this application are as follows:
[0030] This application provides a composite VOCs concentration homogenizer. First, steam-activated attapulgite clay undergoes high-temperature steam treatment to expand its layered structure and remove impurities, forming abundant mesoporous-microporous composite channels, enhancing its adsorption capacity and diffusion kinetics for VOCs. Second, phosphonic acid-modified diatomaceous earth introduces phosphonic acid groups through the esterification reaction of silanol groups on the diatomaceous earth surface with phosphonic acid molecules, providing chemisorption sites for polar VOCs. This modified diatomaceous earth is then combined with nano-ZrO2 and mesoporous silica. Nano-ZrO2 catalyzes the degradation of some VOCs through its surface Lewis acid sites, while mesoporous silica provides ordered mesoporous channels, promoting the transport and temporary storage of large molecular VOCs. During the compounding process, powdered activated carbon, as a high specific surface area substrate, is mechanically mixed with the steam-activated attapulgite clay and modified diatomaceous earth compound system, initially combining through van der Waals forces and hydrogen bonds to form a hierarchical pore structure. The addition of molecular sieves further provides uniform micropores, achieving selective adsorption of VOCs molecules of specific sizes. Subsequently, lubricant and binder are added and uniformly dispersed in deionized water medium. The cross-linking effect of the binder forms a three-dimensional network structure, fixing the position of each component and preventing stratification during use.
[0031] Ultimately, this composite homogenizer achieves dynamic adsorption-desorption cycle and homogenization of VOC concentration through the synergistic effect of multiple components: the micropores of powdered activated carbon and molecular sieves rapidly adsorb small-molecule VOCs when the VOC concentration in the exhaust gas is high, while at low concentrations, the uniform pore size and concentrated adsorption energy distribution facilitate the desorption and release of adsorbed molecules; the medium and large pores of steam-activated attapulgite clay and mesoporous silica provide buffer capacity through physical adsorption, ensuring that the adsorbed VOCs can be smoothly desorbed with changes in concentration gradient; modified diatomaceous earth and nano-ZrO2 reduce the peak concentration through chemical adsorption and catalytic conversion, while avoiding the accumulation of strongly adsorbed species. The multi-level pore structure synergistically regulates the diffusion, distribution, and reversible desorption of VOCs in different pore sizes, thereby achieving stable homogenization through a sensitive adsorption-desorption balance when the concentration fluctuates. Attached Figure Description
[0032] Figure 1 This is a photograph of the composite VOCs concentration homogenizer prepared in Example 3.
[0033] Figure 2 This is a schematic diagram of the testing process for the homogenization effect of the composite VOCs concentration homogenizers prepared in Examples 1-3 and Comparative Examples 1-4.
[0034] Figure 3 The graph shows the concentration change trend of the composite VOCs concentration homogenizers prepared in Example 3 and Comparative Examples 1-4. Detailed Implementation
[0035] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.
[0036] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.
[0037] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.
[0038] The following will describe in detail, with reference to different embodiments, a composite VOCs concentration homogenizer and its preparation method provided in this application.
[0039] Example 1
[0040] like Figure 1 As shown, this embodiment provides a method for preparing a composite VOCs concentration homogenizer, including the following steps:
[0041] S1. Pulverize the attapulgite clay and place it in a high-temperature activation furnace. Pass saturated steam through it and activate it at 300°C for 2 hours. Cool it to room temperature and grind it through a 100-mesh sieve to obtain steam-activated attapulgite clay.
[0042] S2. The diatomaceous earth is pulverized and passed through a 100-mesh sieve, then added to deionized water and stirred to disperse, forming a diatomaceous earth suspension. The amount of deionized water added is 30% of the total amount of deionized water. Phosphonic acid is added and stirred at 60°C for 2 hours. The mixture is then cooled, filtered, washed until the pH reaches 7, dried, and ground through a 100-mesh sieve to obtain phosphonic acid-modified diatomaceous earth. The mass ratio of diatomaceous earth to phosphonic acid is 5:1.
[0043] S3. Add phosphonic acid modified diatomaceous earth, nano ZrO2 and mesoporous silica into a high-speed mixer and mix at a mass ratio of 60:10:10 for 30 minutes at a speed of 3000 r / min to obtain modified diatomaceous earth;
[0044] S4. Take powdered coal-based carbon, the steam-activated attapulgite clay, the modified diatomaceous earth, ZSM-5 molecular sieve, calcium stearate and polyvinyl alcohol and put them into a mixer. Dry mix them at a speed of 300 r / min for 10 min to obtain a mixture.
[0045] S5. Add the remaining deionized water to the mixture, mix well, shape, dry at 60°C for 4 hours, and then heat-cur at 100°C for 1 hour to obtain a composite VOCs concentration homogenizer; the mass ratio of the powdered coal-based carbon, steam-activated attapulgite clay, modified diatomaceous earth, ZSM-5 molecular sieve, calcium stearate, polyvinyl alcohol and deionized water is 20:10:5:5:0.5:3:30.
[0046] Example 2
[0047] like Figure 1 As shown, this embodiment provides a method for preparing a composite VOCs concentration homogenizer, including the following steps:
[0048] S1. Pulverize the attapulgite clay and place it in a high-temperature activation furnace. Pass saturated steam through it and activate it at 400°C for 3 hours. Cool it to room temperature and grind it through a 150-mesh sieve to obtain steam-activated attapulgite clay.
[0049] S2. The diatomaceous earth is pulverized and passed through a 150-mesh sieve, then added to deionized water and stirred to disperse, forming a diatomaceous earth suspension. The amount of deionized water added is 35% of the total amount of deionized water. Phosphonic acid is added and stirred at 75°C for 3 hours. The mixture is then cooled, filtered, washed until the pH reaches 8, dried, and ground through a 150-mesh sieve to obtain phosphonic acid-modified diatomaceous earth. The mass ratio of diatomaceous earth to phosphonic acid is 7:1.
[0050] S3. Phosphonic acid modified diatomaceous earth, nano ZrO2 and mesoporous silica are added to a high-speed mixer and mixed at a mass ratio of 70:20:15 for 45 minutes at a speed of 4000 r / min to obtain modified diatomaceous earth;
[0051] S4. Take powdered wood-based carbon, the steam-activated attapulgite clay, the modified diatomaceous earth, SBA-15 molecular sieve, zinc stearate and hydroxymethyl cellulose and put them into a mixer. Dry mix them at a speed of 500 r / min for 15 min to obtain a mixture.
[0052] S5. Add the remaining deionized water to the mixture, mix well, shape, dry at 80°C for 6 hours, and then heat-cur at 120°C for 2 hours to obtain a composite VOCs concentration homogenizer; the mass ratio of the powdered wood-based carbon, steam-activated attapulgite clay, modified diatomaceous earth, SBA-15 molecular sieve, zinc stearate, hydroxymethyl cellulose and deionized water is 35:20:15:12:3:6:40.
[0053] Example 3
[0054] like Figure 1 As shown, this embodiment provides a method for preparing a composite VOCs concentration homogenizer, including the following steps:
[0055] S1. Pulverize the attapulgite clay and place it in a high-temperature activation furnace. Pass saturated steam through it and activate it at 500°C for 4 hours. Cool it to room temperature and grind it through a 200-mesh sieve to obtain steam-activated attapulgite clay.
[0056] S2. The diatomaceous earth is pulverized and passed through a 200-mesh sieve, then added to deionized water and stirred to disperse, forming a diatomaceous earth suspension. The amount of deionized water added is 40% of the total amount of deionized water added. Phosphonic acid is added and stirred at 90°C for 4 hours. The mixture is then cooled, filtered, washed until the pH reaches 7.5, dried, and ground through a 200-mesh sieve to obtain phosphonic acid-modified diatomaceous earth. The mass ratio of diatomaceous earth to phosphonic acid is 10:1.
[0057] S3. Phosphonic acid modified diatomaceous earth, nano ZrO2 and mesoporous silica are added to a high-speed mixer and mixed at a mass ratio of 80:25:20 for 60 min at a speed of 5000 r / min to obtain modified diatomaceous earth;
[0058] S4. Take powdered wood-based carbon, the steam-activated attapulgite clay, the modified diatomaceous earth, beta molecular sieve, polyethylene wax and starch and put them into a mixer. Dry mix them at a speed of 800 r / min for 20 min to obtain a mixture.
[0059] S5. Add the remaining deionized water to the mixture, mix well, shape, dry at 100℃ for 8 hours, and then cure at 150℃ for 3 hours to obtain a composite VOCs concentration homogenizer, such as... Figure 1 As shown; the mass ratio of the powdered coal-based carbon, steam-activated attapulgite clay, modified diatomaceous earth, beta molecular sieve, polyethylene wax, starch and deionized water is 50:30:25:20:5:10:50.
[0060] Comparative Example 1
[0061] A method for preparing a composite VOCs concentration homogenizer, which differs from Example 3 in that the attapulgite clay in S1 is not steam activated.
[0062] Comparative Example 2
[0063] A method for preparing a composite VOCs concentration homogenizer, which differs from Example 3 in that S2 is omitted and the diatomaceous earth in S3 is not modified.
[0064] Comparative Example 3
[0065] A method for preparing a composite VOCs concentration homogenizer, which differs from Example 3 in that molecular sieves are not added in S4.
[0066] Comparative Example 4
[0067] A method for preparing a composite VOCs concentration homogenizer differs from Example 3 in that S1 uses only powdered coal-based carbon, omitting steam-activated attapulgite clay and modified diatomaceous earth, while the remaining steps and total mass ratio are completely consistent with Example 3.
[0068] Performance testing:
[0069] 1. Basic performance test: The specific surface area, pore volume and average pore size of the composite VOCs concentration homogenizers of Examples 1-3 and Comparative Examples 1-4 were measured using an ASAP 2020 HD88 fully automatic gas adsorption instrument. The results are shown in Table 1.
[0070] 2. Homogenization effect test: In such Figure 2 In the test procedure shown, two bottles of simulated waste gas with significantly different total hydrocarbon concentrations were prepared. One bottle had a total hydrocarbon concentration of 100,000 mg / Nm³, and the other had a total hydrocarbon concentration of 100 mg / Nm³. The equilibrium gas for both bottles was air, and the organic components were C6-C10 hydrocarbons. To simulate the VOCs concentration fluctuations in actual industrial production, the composite VOCs concentration homogenizers of Examples 1-3 and Comparative Examples 1-4 were loaded into the test device, and the simulated waste gas was circulated through the homogenizer in the following manner, with the space velocity of the waste gas passing through the homogenizer controlled at 1000 h⁻¹ throughout the process. - ¹:(1)Continuously introduce high-concentration (100000mg / Nm³) simulated waste gas into the homogenizer for 20 minutes; (2)Close the high-concentration waste gas inlet and switch to introducing low-concentration (100mg / Nm³) simulated waste gas for 20 minutes; (3)Close the low-concentration waste gas inlet and switch to introducing high-concentration simulated waste gas again for 20 minutes; Repeat the above three steps to form a cyclical inlet mode to continuously simulate the waste gas working condition with drastic fluctuations in total hydrocarbon concentration; During the test, the total hydrocarbon concentration of the waste gas at the outlet of the homogenizer is measured in real time to evaluate the homogenization effect of the homogenizer; The specific data results of this test are detailed in Table 2.
[0071] The performance test data analysis is as follows:
[0072] Table 1 shows the results obtained from Examples 1-3 and Comparative Examples 1-4.
[0073] Basic performance test data of composite VOCs concentration homogenizer
[0074]
[0075] As shown in Table 1, the composite VOCs concentration homogenizers prepared in Examples 1-3 of this application have significantly higher specific surface area (620-730 m² / g) and total pore volume (0.68-0.76 cm³ / g) than the comparative examples, and a more moderate average pore size distribution (3.2-3.6 nm). The core reason is that the examples use steam to activate attapulgite clay to unclog pores, introduce active sites by combining phosphonic acid with nano-ZrO2 and mesoporous silica to modify diatomaceous earth, and then combine it with molecular sieves to construct a multi-level interconnected pore system of micropores-mesopores-macropores, forming a synergistic effect. Its pore structure is similar to that of C6-C10. The high degree of diameter matching in hydrocarbon molecular dynamics provides an excellent structural basis for the rapid adsorption and stable desorption of VOCs. However, each comparative example has key defects. Comparative example 1 suffers from pore blockage due to unactivated attapulgite, resulting in a specific surface area of only 410 m² / g. Comparative example 2, lacking active sites and mesoporous modification due to unmodified diatomite, has a specific surface area reduced to 380 m² / g and a total pore volume of only 0.39 cm³ / g. Comparative example 3 suffers from insufficient hierarchical pore structure due to the absence of molecular sieves. Comparative example 4, using only coal-based carbon without synergistic effects, has a specific surface area of only 220 m² / g and a total pore volume of only 0.28 cm³ / g. 3 / g, none of them can form a suitable porous structure system, which leads to their adsorption-desorption performance and homogenization potential being far inferior to those of the embodiments in this application, fully demonstrating the rationality and superiority of the preparation process and component design in this application.
[0076] Table 2 shows the results obtained from Examples 1-3 and Comparative Examples 1-4.
[0077] Performance test data of composite VOCs concentration homogenizer
[0078]
[0079] The outlet concentrations in Examples 1-3 remained stable, generally ranging from 34120 to 57720 mg / Nm³. Specifically, when the inlet concentration was high (100000 mg / Nm³), the outlet concentration stabilized at 50230–57720 mg / Nm³, and when the inlet concentration was low (100 mg / Nm³), the outlet concentration remained stable at 50230–57720 mg / Nm³. 3 During intake, the outlet concentration remained stable at 34120–43960 mg / Nm³. Even after multiple high and low concentration cycles (290 min test duration), the outlet concentration showed minimal fluctuation and strong stability. Figure 3 As shown, the homogenizing agent prepared in this application fully demonstrates its excellent adsorption, buffering, and sustained-release synergistic ability—this is due to its hierarchical porous structure and the synergistic effect of its components, which can rapidly adsorb and store VOCs at high concentrations and stably desorb and replenish them at low concentrations, thus achieving concentration homogenization. In contrast, all comparative examples show a trend of significantly increasing fluctuation range of outlet concentration with prolonged testing time, such as... Figure 3As shown: Comparative Example 1 (unactivated attapulgite) had an outlet concentration of 18950 mg / Nm³ when using high-concentration inlet gas. 3 Increased to 98950 mg / Nm 3 When the inlet concentration is low, it is 680 mg / Nm³. 3 Increased to 1120 mg / Nm 3 The fluctuation was more pronounced in Comparative Example 2 (unmodified diatomaceous earth), with the high concentration at the outlet increasing from 15620 mg / Nm³ to 95680 mg / Nm³. 3 Comparative Example 3 (without molecular sieve) showed a high concentration outlet of 16890 mg / Nm³. 3 Increased to 97820 mg / Nm 3 In Comparative Example 4 (coal-based carbon only), the outlet concentration increased from 8960 mg / Nm³ to 94560 mg / Nm³ when the inlet gas concentration was high. 3 The concentration of VOCs in the inlet gas is only 210–480 mg / Nm³, resulting in extremely poor homogenization. In summary, the homogenization stability of Examples 1–3 is far superior to that of the comparative examples, effectively coping with the conditions of drastic fluctuations in VOCs concentration, and fully verifying the rationality and superiority of the preparation process and component design of this application.
[0080] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.
Claims
1. A composite VOC concentration homogenizing agent, characterized by, The product comprises powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth, molecular sieves, lubricants, binders, and deionized water; the steam-activated attapulgite clay is obtained by steam activation treatment of attapulgite clay; the modified diatomaceous earth is obtained by compounding phosphonic acid-modified diatomaceous earth, nano-ZrO2, and mesoporous silica; the phosphonic acid-modified diatomaceous earth is obtained by reacting diatomaceous earth with phosphonic acid; the powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth, molecular sieves, lubricants, binders, and deionized water... The mass ratio of water is (20~50):(10~30):(5~25):(5~20):(0.5~5):(3~10):(30~50); the mass ratio of phosphonic acid modified diatomaceous earth, nano ZrO2 and mesoporous silica is (60~80):(10~25):(10~20); the mass ratio of diatomaceous earth to phosphonic acid is (5~10):1; the molecular sieve includes any one of ZSM-5, SBA-15 and beta molecular sieves.
2. The composite VOC concentration homogenizing agent according to claim 1, characterized by, The powdered activated carbon includes powdered coal-based carbon or powdered wood-based carbon; the lubricant includes any one of calcium stearate, zinc stearate, and polyethylene wax; the binder includes any one of polyvinyl alcohol, hydroxymethyl cellulose, and starch.
3. A method for preparing a composite VOCs concentration homogenizer as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. The attapulgite clay is crushed and placed in a high-temperature activation furnace. Saturated steam is introduced for steam activation treatment. After cooling to room temperature, it is ground and sieved to obtain steam-activated attapulgite clay. S2. Pulverize and sieve the diatomaceous earth, add it to deionized water and stir to disperse it, forming a diatomaceous earth suspension. Add phosphonic acid and stir to react. Cool, filter, wash, dry, grind and sieve to obtain phosphonic acid modified diatomaceous earth. S3. The phosphonic acid modified diatomaceous earth, nano ZrO2 and mesoporous silica are added to a high-speed mixer and mixed at high speed to obtain modified diatomaceous earth; S4. Powdered activated carbon, steam-activated attapulgite clay, modified diatomaceous earth, molecular sieve, lubricant, and binder are put into a mixer and dry-mixed to obtain a mixture. S5. Add deionized water to the mixture, mix well, shape, dry and heat-insulate to cure, and obtain a composite VOCs concentration homogenizer.
4. The preparation method of the composite VOCs concentration homogenizer according to claim 3, characterized in that, In S1, the temperature of the steam activation treatment is 300-500℃ and the time is 2-4h.
5. The preparation method of a composite VOCs concentration homogenizer according to claim 3, characterized in that, In S2, the stirring reaction is carried out at a temperature of 60–90°C for 2–4 hours; the washing is carried out until the pH reaches 7–8; and the grinding and sieving are carried out with a mesh size of 100–200 mesh.
6. The preparation method of a composite VOCs concentration homogenizer according to claim 3, characterized in that, In S3, the high-speed mixing speed is 3000-5000 r / min and the time is 30-60 min.
7. The preparation method of a composite VOCs concentration homogenizer according to claim 3, characterized in that, In S4, the dry mixing speed of the mixer is 300-800 r / min and the time is 10-20 min.
8. The preparation method of a composite VOCs concentration homogenizer according to claim 3, characterized in that, In S5, the curing temperature is 100~150℃ and the time is 1~3h; the drying temperature is 60~100℃ and the time is 4~8h.