A double filter cartridge cyclone VOCs adsorption method based on modified fly ash material
The double filter cartridge adsorption device with modified fly ash adsorbent addresses uneven distribution and high costs in traditional VOCs removal by ensuring uniform airflow and easy replacement, enhancing efficiency and reducing operational expenses while maintaining continuous VOCs removal.
Patent Information
- Application Number
- CN202011275443.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-11-09
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2040-11-09
AI Technical Summary
Existing VOCs adsorption technologies face issues with high operating costs due to frequent replacement of expensive adsorbents like activated carbon, uneven adsorption distribution, and inefficient utilization of adsorbent materials, particularly in fixed and moving bed structures.
A double filter cartridge adsorption device using modified fly ash as an adsorbent, featuring a tangential air inlet and centrifugal circulation, which balances airflow resistance and ensures uniform distribution, allowing for simultaneous use of inner and outer filter cartridges, and facilitates easy replacement of the adsorbent component.
The method enhances adsorption efficiency, reduces equipment size, lowers operational costs, and extends the regeneration cycle of the adsorbent, ensuring continuous and stable VOCs removal with high utilization rates and minimal environmental impact.
Smart Images
Figure CN112387066B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a new method for efficiently absorbing VOCs by modified fly ash, and in particular to a new VOCs treatment process capable of recovering useful components of VOCs and reusing adsorbents. Technical Background
[0002] VOCs waste gas mainly refers to the general term for organic compounds such as hydrocarbons, ketones, lipids, phenols, aldehydes, etc. that are emitted into the air. These organic compounds exist in the air and will cause serious harm to the human body. For example, organic waste gases such as formaldehyde and polycyclic aromatic hydrocarbons are highly carcinogenic. When the human body is in such an environment for a long time, the possibility of cancer will increase significantly; some organic waste gases also show strong toxic effects. After excessive inhalation, the human body will cause coma or even death. In addition, VOCs waste gas will also cause environmental problems such as haze, acid rain, ozone layer depletion, and atmospheric warming, which will have a relatively bad impact on the ecological environment.
[0003] Adsorption technology is a technology that is currently widely used. Through this technology, the corresponding VOCs waste gas can be adsorbed on the surface of the material, thereby achieving the effect of purifying the air. At present, the technology of recovering VOCs by adsorption is relatively mature, but most of them use activated carbon or molecular sieves as adsorbents, and the adsorbents need to be replaced frequently to prevent the adsorbents from adsorbing more pollutants and causing the adsorption capacity to weaken. In addition, due to the high price of commercial adsorbents, high-frequency disassembly and replacement will also increase the operating cost of the system.
[0004] Traditional adsorption devices often use fixed bed or moving bed adsorption structures. During the adsorption process, there may be technical problems that need to be improved, such as the adsorption bed being too thick, large pressure loss, uneven distribution of inlet pressure leading to uneven adsorption of the adsorption bed, and inability to fully utilize the adsorbent.
[0005] Fly ash, the product of coal-fired boiler incineration, was originally a solid waste to be treated, but its particles are porous honeycomb structure, with a large specific surface area and high adsorption activity. The particle size range is 0.5-300μm. In addition, the bead wall has a porous structure with a porosity of up to 50%-80%, and has a strong adsorption capacity. It is entirely possible to replace adsorbents such as activated carbon and molecular sieves and become a more economical alternative. Experiments have shown that the main components of fly ash are aluminosilicates and oxide forms of elements such as silicon, aluminum, iron, and calcium. As an adsorbent, it is resistant to high temperature and corrosion, has a small regeneration loss, stable chemical properties, a high reuse rate, and simple and easy desorption technology. Summary of the invention
[0006] In view of the shortcomings of traditional adsorption process technology, the present invention provides a new method for efficiently adsorbing VOCs based on modified fly ash materials. The method can improve the adsorption effect, increase the utilization rate of the adsorbent, and has low cost.
[0007] To achieve the above purpose, the present invention adopts the following technical scheme. The adsorption device includes: a shell system consisting of a support leg 1, a shell 21, a top cover 4 connected to the shell 21, an air inlet pipe 2, an air outlet pipe 5 and a regeneration exhaust gas outlet pipe 10; an adsorption system consisting of a double filter cartridge adsorption component 6 consisting of an adsorption component top plate 16, an adsorption component bottom plate 20, an outer filter cartridge 8 and an inner filter cartridge 9, an adsorption component support plate 8, an outer filter cartridge dust removal filter 12, an inner filter cartridge dust removal filter 17 and a modified fly ash adsorbent 14 arranged in the inner and outer filter cartridges; and a regeneration system consisting of a regeneration blowing pipe 3. The adsorption device is connected by a shell 1 and a top cover 2 to form a closed space, and a double-filter cartridge adsorption assembly 6 is arranged on a support plate in the device; the double-filter cartridge adsorption assembly 6 is composed of an outer filter cartridge 8 and an inner filter cartridge 9 to form a double-filter cartridge structure, and two gas flow spaces, a central airway 10 and a sandwich annular airway 11, are formed inside the double-filter cartridge adsorption assembly. An adsorption assembly air inlet 12 is arranged at the bottom of the outer filter cartridge 8, and the shape and size of the air inlet match the air inlet pipe 3 of the adsorption device; the overall frame of the double-filter cartridge adsorption assembly 6 is spliced by metal materials and high molecular polymer materials, and is characterized in that the space between the outer filter cartridge 8 and the inner filter cartridge 9 is closed up and down, and both sides are open for airflow to pass through, the upper and lower ends of the central airway 10 are connected to the outside of the assembly, the upper end of the sandwich annular airway 11 is closed, and the lower end side is connected to the outside of the assembly through the assembly air inlet 12; the outer filter Granular or shaped plate-type modified fly ash adsorbent can be filled inside the cylinder 8 and the inner filter cylinder 9, which is characterized in that the inner filter cylinder 9 is a circular cylindrical structure, and the outer filter cylinder 8 is a circular trapezoidal structure that is thin on the top and thick on the bottom; the air inlet pipe 3 is connected to the shell 1 and extends inward, and is connected with the interlayer annular air duct 11 after passing through the outer filter cylinder 8 of the double filter cartridge adsorption assembly 6, and is characterized in that the air inlet pipe 3 is eccentrically installed, and its axis is perpendicular to the axis of the shell, but not on the same vertical plane, and the air flow flows tangentially into the interlayer annular air duct 11 through the air inlet, forming a circulation in the air duct; the air outlet pipe 4 is connected to the top cover 2 and is connected to the upper part of the space inside the shell 1; a plurality of vertical regeneration blowing pipes 7 are arranged on the inner wall of the shell outside the outer filter cartridge 8, and the regeneration exhaust gas outlet pipe 5 is connected to the bottom of the shell 1 and is connected to the lower part of the space inside the shell.
[0008] When the adsorption device is operating normally, the VOCs waste gas enters the filter cartridge interlayer annular airway 11 tangentially from the air inlet pipe 3 through the adsorption assembly air inlet 12, forming a circulation in the airway and spirally rising. The waste gas sweeps the surface of the adsorption filter cartridge while rotating. Part of the waste gas enters the outer filter cartridge 8 under the action of centrifugal dynamic pressure, and enters the interlayer space between the shell and the double filter cartridge adsorption assembly 6 after being purified by the modified fly ash adsorbent in the filter cartridge. The other part of the waste gas enters the inner filter cartridge 9 under the action of the static pressure of the air flow, and enters the central airway 10 of the adsorption assembly after being purified. The two parts of the purified gas are collected at the top of the device and discharged through the outlet pipe 4. When the adsorption bed is penetrated, the regeneration spray pipe 7 sprays superheated steam or high-temperature nitrogen and other media to regenerate the double filter cartridge adsorption assembly 6. The regenerated waste gas enters the central airway 10 through the outer filter cartridge 8, the double filter cartridge interlayer annular airway 11 and the inner filter cartridge 9, and is discharged from the lower outlet of the central airway 10 and the regeneration waste gas outlet pipe 5. The VOCs components in the regenerated waste gas can be recycled through condensation, distillation and other technologies.
[0009] The double filter cartridge adsorption component 6 of the adsorption device is an integrated detachable component. When the adsorbent fails, the component can be replaced as a whole, which is easy to operate.
[0010] Because the flow velocity is high and the centrifugal dynamic pressure is large at the initial stage when the airflow enters the device, the bottom of the outer filter cartridge 8 is thickened to balance the resistance of the inner and outer filter cartridges. As the airflow rotates and rises, the air volume decreases, and the centrifugal dynamic pressure also decreases under the action of friction. The pressure applied by the airflow to the inner and outer filter cartridges is nearly balanced, so the adsorption bed layer on the upper part of the outer filter cartridge 8 gradually becomes thinner, so that the amount of waste gas is evenly distributed between the inner and outer filter cartridges. When the thickness ratio of the bottom of the inner and outer filter cartridges is 1:1.5-1:2, and the thickness ratio of the top of the inner and outer filter cartridges is 1:1-1:1.2, the adsorption effect of the device is the best.
[0011] The adsorption device is a thin bed adsorption, with the thickness of the inner filter cartridge 9 as the reference, the bed thickness is 0.05-0.15m, and the thickness of the outer filter cartridge 8 can be selected within the optimal ratio of the inner and outer filter cartridge thicknesses. Depending on the thickness of the bed, the empty bed gas velocity can be set to 5-25m / min.
[0012] The ratio of the height to the thickness of the interlayer annular air channel 11 in the double filter cartridge adsorption assembly 6 should be greater than 5:1 to ensure that the characteristics of uniform purging, balanced partial pressure and reasonable diversion of the method are fully utilized.
[0013] In the process of adsorbing VOCs by the thin-layer modified fly ash filter cartridge, the adsorbent penetration time is 30-45 minutes, indicating that the modified fly ash has good adsorption performance for VOCs; the modified fly ash filter cartridge after multiple regeneration can still achieve a penetration time of 25-30 minutes when repeatedly used to adsorb VOCs, indicating that it has good regeneration performance. When this method is applied industrially, a double-tower alternate adsorption regeneration process system can be used to ensure the continuous, stable and safe operation of the process.
[0014] Compared with the existing adsorption method, the present invention has the following advantages:
[0015] 1) The adsorption device of the present invention is a double filter cartridge adsorption structure. The inner and outer filter cartridges are adsorbed simultaneously, which can increase the filtration area. The equipment structure is compact and the floor space is reduced.
[0016] 2) The present invention adopts a tangential air inlet cyclone adsorption method, which is conducive to uniform distribution of air pressure, so that the adsorbent is utilized layer by layer, avoiding the occurrence of channel flow, reducing the dead layer thickness, improving the utilization rate of the adsorbent, and extending the regeneration cycle.
[0017] 3) The outer filter cartridge of the present invention is configured as a thin-upper-thick-lower structure, which helps to balance the resistance of the inner and outer filter cartridges to the airflow, making the air volume distribution passing through the inner and outer filter cartridges more uniform and reasonable.
[0018] 4) Modified fly ash composite material is used as adsorbent. The adsorbent can be processed into granular form and filled in the filter cartridge, or processed into a plate form and directly inserted into the filter cartridge. The adsorbent has good adsorption effect, low cost, and can be regenerated and reused many times.
[0019] 5) The adsorbent and its loading container are integrated into a double-cartridge adsorption component. After the adsorbent fails, the component can be replaced as a whole. The operation is quick and convenient, and the environmental pollution that may be caused by the transportation of bulk adsorbent is avoided. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a schematic diagram of the structure of the double filter cartridge adsorption device of the present invention.
[0021] Figure 2 This is a schematic diagram of the structure of the double filter cartridge adsorption assembly of the present invention.
[0022] In the figure: 1. Shell, 2. Top cover, 3. Air inlet pipe, 4. Air outlet pipe, 5. Regeneration exhaust gas outlet pipe, 6. Double filter cartridge adsorption assembly, 7. Regeneration blow pipe, 8. Outer filter cartridge, 9. Inner filter cartridge, 10. Central air duct, 11. Interlayer annular air duct, 12. Adsorption assembly air inlet.
[0023] Figure 3 The effect of different VOCs concentrations on the adsorption effect in the present invention
[0024] Figure 4 The effect of the number of regenerations on the adsorption effect in the present invention DETAILED DESCRIPTION
[0025] The present invention will be further described below in conjunction with the accompanying drawings:
[0026] The adsorption device of the present invention is a double filter cartridge adsorption device based on modified fly ash material, and its specific structure is as follows: Figure 1 and Figure 2 shown.
[0027] When the adsorption device is operating normally, the VOCs waste gas enters the filter cartridge interlayer annular airway 11 tangentially from the air inlet pipe 3 through the adsorption assembly air inlet 12, forming a circulation in the airway and spirally rising. The waste gas sweeps the surface of the adsorption filter cartridge while rotating. Part of the waste gas enters the outer filter cartridge 8 under the action of centrifugal dynamic pressure, and enters the interlayer space between the shell and the double filter cartridge adsorption assembly 6 after being purified by the modified fly ash adsorbent in the filter cartridge. The other part of the waste gas enters the inner filter cartridge 9 under the action of the static pressure of the air flow, and enters the central airway 10 of the adsorption assembly after being purified. The two parts of the purified gas are collected at the top of the device and discharged through the outlet pipe 4. When the adsorption bed is penetrated, the regeneration spray pipe 7 sprays superheated steam or high-temperature nitrogen and other media to regenerate the double filter cartridge adsorption assembly. The regenerated waste gas enters the central airway 10 through the outer filter cartridge 8, the double filter cartridge interlayer annular airway 11 and the inner filter cartridge 9, and is discharged from the lower outlet of the central airway 10 and the regeneration waste gas outlet pipe 5. The VOCs components in the regenerated waste gas can be recycled through condensation, distillation and other technologies.
[0028] According to the above method, the following experiments were carried out:
[0029] The bottom thickness ratio of the inner and outer filter cartridges is 1:1.8, and the top thickness ratio of the inner and outer filter cartridges is 1:1; the bed thickness of the inner filter cartridge 9 is 0.05m, the upper thickness of the outer filter cartridge 8 is 0.05m, and the lower thickness is 0.09m; the empty bed gas velocity is set to 10m / min. The height to thickness ratio of the interlayer annular airway 11 is 8:1.
[0030] In the experiment, toluene was used as the target pollutant, and the toluene exhaust gas concentration was set to 400 mg / m 3 and 800 mg / m 3 . Figure 3 The figure shows the effect of different VOCs concentrations on the adsorption effect. The figure shows that in the initial stage of adsorption, the outlet toluene concentration of the device has not been detected. As the adsorption time increases, the adsorption bed is penetrated, and the outlet concentration increases slowly at first and then rapidly. The inlet concentration is 400 mg / m 3 and 800 mg / m 3The penetration time of the adsorption curve is about 45min and 24min respectively, and the adsorption saturation time is about 63min and 42min respectively. It can be seen that the present invention has a good adsorption effect on VOCs waste gas. Figure 4 In order to determine the effect of regeneration times on adsorption, the inlet concentration in this experiment was fixed at 400 mg / m 3 , other parameters remain unchanged, and 20 adsorption regeneration cycle experiments were carried out. The figure shows that within 10 regenerations, the adsorption effect of the modified fly ash adsorbent did not decrease significantly. During the 10th to 20th regeneration, the adsorption effect showed a downward trend, but after the 20th regeneration, the penetration time of the adsorbent can still reach about 30 minutes. It can be seen that due to the relatively stable chemical properties of the modified fly ash adsorbent, it has a good multiple regeneration adsorption capacity.
[0031] When the present invention is applied industrially, a process system of double-tower adsorption and regeneration in turn can be adopted to ensure continuous, stable and safe operation of the process.
[0032] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A double-filter cyclone VOCs adsorption method based on modified fly ash material, characterized in that: The adsorption device includes: A shell system consisting of a support foot (1), a shell (21), a top cover (4) connected to the shell (21), an air inlet pipe (2), an air outlet pipe (5) and a regeneration waste gas outlet pipe (10); an adsorption system consisting of a double filter cartridge adsorption assembly (6) consisting of an adsorption assembly top plate (16), an adsorption assembly bottom plate (20) and an outer filter cartridge (8) and an inner filter cartridge (9), an adsorption assembly support plate, an outer filter cartridge dust removal filter (12), an inner filter cartridge dust removal filter (17) and a modified fly ash adsorbent (14) arranged in the inner and outer filter cartridges; and a regeneration system consisting of a regeneration blowing pipe (3); The VOCs waste gas passes through the outer filter cartridge (8) of the adsorption assembly (6) from the air inlet pipe (2) of the device and enters the bottom of the double filter cartridge sandwich annular airway in a tangential direction, forming a circulation in the airway and spirally ascending; the waste gas rotates and passes through the outer filter cartridge (8) and the inner filter cartridge (9) respectively under the action of centrifugal dynamic pressure and airflow static pressure, and the VOCs components in the waste gas are adsorbed and removed by the modified fly ash adsorbent (14) in the filter cartridge; The double filter cartridge adsorption assembly (6) is composed of an outer filter cartridge and an inner filter cartridge, forming a double filter cartridge structure, wherein two gas flow spaces, a central airway and an interlayer annular airway, are formed inside the double filter cartridge. An adsorption assembly air inlet is arranged at the bottom of the outer filter cartridge. The double filter cartridge adsorption assembly is an integrated detachable assembly. The inner filter cartridge (9) is a circular cylindrical structure, and the outer filter cartridge (8) is a circular trapezoidal structure that is thin at the top and thick at the bottom. The bottom thickness ratio of the inner and outer filter cartridges is 1:1.8, and the top thickness ratio of the inner and outer filter cartridges is 1:1; the bed thickness of the inner filter cartridge (9) is 0.05m, the upper thickness of the outer filter cartridge (8) is 0.05m, and the lower thickness is 0.09m; the height and thickness ratio of the interlayer annular airway (11) is 8:
1.
2. The double-filter cyclone VOCs adsorption method based on modified fly ash material according to claim 1 is characterized in that: The modified fly ash adsorbent (14) is in a granular or shaped plate structure.