A method for deep regeneration of macroporous resin for adsorbing waste gas

Abstract

This invention relates to a method for deep regeneration of macroporous resin that adsorbs waste gas, belonging to the technical field of resin regeneration. The regeneration method includes adding an organic solvent, an aqueous sodium hydroxide solution, and a phase transfer catalyst to the resin to be regenerated; heating and stirring followed by solid-liquid separation; and washing the resin to obtain regenerated macroporous resin. This invention uses an organic solvent to elute adsorbates from the macroporous resin, while simultaneously using a phase transfer catalyst to promote the separation of macromolecular compounds from the macroporous resin. This allows for the deep removal of macromolecular compounds that are difficult to remove with organic solvents, enabling deep regeneration of the resin and extending its service life.

Description

Technical Field

[0001] This invention relates to the technical field of resin regeneration, and specifically to a method for deep regeneration of macroporous resin that adsorbs waste gas. Background Technology

[0002] Macroporous adsorption resins are a new type of high-molecular polymer adsorption material that has developed rapidly in recent years, possessing a three-dimensional network structure. Macroporous adsorption resins are characterized by high cross-linking degree, porosity, and large specific surface area. The pores inside macroporous adsorption resins have a three-dimensional structure. Compared with activated carbon, which is commonly used for adsorbing organic waste gases, macroporous adsorption resins are spherical particles, resulting in lower adsorption resistance and faster adsorption speed. They can perform not only surface adsorption but also framework adsorption and group adsorption. Therefore, macroporous adsorption resins outperform activated carbon and molecular sieves in adsorbing organic waste gases.

[0003] Because macroporous adsorption resins are easily broken at high temperatures, and due to friction, the broken resin powder clogs the gaps between resin particles, affecting gas distribution and flow, and increasing the resistance of the adsorption tank. Simultaneously, the complex composition of the waste gas, with the continuous accumulation of high-boiling-point, low-saturated vapor-pressure macromolecular compounds, significantly reduces the resin's adsorption and desorption regeneration efficiency. To ensure the adsorption capacity of the adsorption tank, it is necessary to regularly check and replenish the depleted resin. However, with the accumulation of resin powder and difficult-to-desorb components, the resin in a typical waste gas resin adsorption tank generally needs to be completely replaced every 3-5 years, depending on its operating condition.

[0004] Compared to activated carbon and molecular sieves, macroporous adsorption resins offer superior adsorption capacity and regenerability. However, the desorption of VOCs differs from that of resins used in wastewater treatment. Resins in wastewater can be washed out with solvents, typically using temperature-induced desorption. Macroporous adsorption resins, however, have lower temperature tolerance than activated carbon and molecular sieves, especially under dry conditions. Their pore structure can change, even leading to breakage. Furthermore, some high-boiling-point, low-saturated vapor-pressure macromolecular compounds in the waste gas are difficult to desorb after adsorption by the resin, resulting in resin poisoning. Although these substances may be present in low concentrations, their accumulation in the resin after adsorption leads to rapid poisoning and resin failure. Summary of the Invention

[0005] Current macroporous resin adsorption devices typically employ online steam desorption, which suffers from limitations such as low desorption temperature and incomplete desorption efficiency for macromolecular compounds with high boiling points and low saturated vapor pressures during fixed-bed desorption. This invention provides a method for deep regeneration of macroporous resin used in waste gas adsorption to address these issues. This invention achieves deep regeneration of the macroporous resin by sieving the waste resin and then utilizing a phase transfer catalyst to thoroughly remove high-boiling-point, low-saturated vapor pressure macromolecular compounds adsorbed within the resin.

[0006] The technical solution of this invention is as follows:

[0007] A method for deep regeneration of macroporous resin for adsorbing waste gas includes the following steps: adding an organic solvent, an aqueous sodium hydroxide solution, and a phase transfer catalyst to the resin to be regenerated; heating and stirring to separate the solid and liquid phases; washing the resin to obtain the regenerated macroporous resin; wherein the phase transfer catalyst is one of a quaternary ammonium salt, a crown ether, or a polyether.

[0008] The specific steps are as follows: First, the resin to be regenerated is sieved to remove broken resin powder and select intact resin particles. Then, the selected intact resin particles are transferred to a stirred tank equipped with stirring and heating functions. Organic solvent, sodium hydroxide aqueous solution, and phase transfer catalyst are added, and macromolecular compounds in the resin are removed under heating conditions. After solid-liquid separation, hydrochloric acid is used to adjust the pH of the resin to promote the dissolution and washing of salts. The resin is washed with water until the ionization degree of the washing solution meets the requirements, thus obtaining regenerated macroporous resin.

[0009] Furthermore, the quaternary ammonium salt is one of tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride (TBAC), or benzyltriethylammonium chloride (TEBA); the crown ether is one of 15-crown-5, 18-crown-6, or dibenzo-18-crown-6; the polyether is one of polyethylene glycol (PEG), polypropylene glycol (PPG), or polyethylene glycol-polypropylene glycol (PEG-PPG) block copolymer; and the amount of the phase transfer catalyst is 0.005~0.05 g / g based on the mass of the macroporous resin.

[0010] Furthermore, the organic solvent is ethanol.

[0011] Furthermore, the sodium hydroxide aqueous solution has a mass concentration of 1% to 5%. The sodium hydroxide aqueous solution can be added directly by adding a pre-prepared sodium hydroxide aqueous solution with a mass concentration of 1% to 5%, or by adding solid sodium hydroxide and then dissolving it in water to obtain a sodium hydroxide aqueous solution with a mass concentration of 1% to 5%. Alternatively, commercially available liquid alkali solution can be used, and diluted with water to obtain a sodium hydroxide aqueous solution with a mass concentration of 1% to 5%.

[0012] Furthermore, the resin powder removed after screening enters the sedimentation tank, is collected, and treated as solid waste.

[0013] The aforementioned method for deep regeneration of macroporous resin for adsorbing waste gas can be implemented using a device with the following structure: The device includes a stirred tank; the inlet of the stirred tank is connected to the outlet of the residue from a first drum screen; the inlet of the first drum screen is connected to a resin adsorption tank via a vacuum pump; the outlet of the stirred tank is connected to both the inlet of the first drum screen and the inlet of a second drum screen; the outlet of the undersize from the second drum screen is connected to the inlet of the stirred tank; the outlet of the residue from the second drum screen is connected to the resin adsorption tank via a vacuum pump; the inlet of the stirred tank is also connected to a dosing device, which is connected to a solvent tank, a liquid alkali tank, a phase transfer catalyst tank, and a hydrochloric acid tank. This device is an integrated unit, easy to operate, and highly safe.

[0014] Furthermore, the undersize outlet of the first drum screen is connected to the sedimentation tank; the sedimentation tank is connected to the filter press via a third vacuum pump.

[0015] The beneficial effects of this invention are as follows:

[0016] The present invention provides a method for deep regeneration of macroporous resins that adsorb waste gas. By using organic solvents to wash off the adsorbates in the macroporous resins and using a phase transfer catalyst to promote the separation of macromolecular compounds from the macroporous resins, the method can deeply remove macromolecular compounds that are difficult to remove with organic solvents, thus enabling deep regeneration of the resins and extending their service life. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the device for deep regeneration of macroporous resin for adsorbing waste gas in Embodiment 1 of the present invention.

[0019] In the diagram, 1-resin adsorption tank, 2-vacuum pump one, 3-drum screen one, 4-stirring vessel, 5-dosing device, 6-vacuum pump two, 7-sedimentation tank, 8-vacuum pump three, 9-filter press, 10-solvent tank, 11-liquid alkali tank, 12-phase transfer catalyst tank, 13-hydrochloric acid tank, 14-drum screen two. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0021] Example 1

[0022] A device for deep regeneration of macroporous resin for adsorbing waste gas includes a stirred tank 4, which is an electrically heated stirred tank; the inlet of the stirred tank 4 is connected to the outlet of the residue of a first drum screen 3; the inlet of the first drum screen 3 is connected to a resin adsorption tank 1 via a vacuum pump 2, which is a diaphragm vacuum pump; the outlet of the stirred tank 4 is connected to the inlet of the first drum screen 3 and the inlet of a second drum screen 14; the outlet of the undersize of the second drum screen 14 is connected to the inlet of the stirred tank 4; the outlet of the residue of the second drum screen 14 is connected to the inlet of the resin adsorption tank 1 via a vacuum pump 6; the inlet of the stirred tank 4 is also connected to a dosing device 5, which is connected to a solvent tank 10, a liquid alkali tank 11, a phase transfer catalyst tank 12, and a hydrochloric acid tank 13; the outlet of the undersize of the first drum screen 3 is connected to a sedimentation tank 7; the sedimentation tank 7 is connected to a filter press 9 via a vacuum pump 8.

[0023] Example 2

[0024] In the apparatus of Example 1, the waste macroporous resin is regenerated. The waste resin originates from the exhaust gas treatment equipment of the chemical and spraying industries. The organic matter adsorbed in the resin mainly consists of acrylic acids such as acrylonitrile, methyl methacrylate, ethyl acrylate, and butyl acrylate, with a content of 20 kg / ton. The specific process is as follows:

[0025] (1) Insert the feed pipe of vacuum pump 2 into the resin layer in resin adsorption tank 1, and use vacuum suction to extract the resin and transport it to drum screen 3. Each batch can process 1000 kg of wet waste resin.

[0026] (2) The drum screen 3 removes the resin powder through the rotating screen, and the resin with intact particles is screened out. The resin powder enters the sedimentation tank 7, and the resin with intact particles enters the mixing tank 4.

[0027] (3) Add 800 kg of water to the electric heating stirring tank, and add 50 kg of 99% ethanol, 25 kg of 32% liquid alkali, and 5 kg of tetrabutylammonium bromide (TBAB) phase transfer catalyst through the dosing device 5. Stir the resin for 5 to 6 hours under the alkaline high temperature environment of pH≥11 and temperature of 80 ℃~95 ℃ and the action of the phase transfer catalyst to deeply remove macromolecular compounds and restore the resin adsorption capacity.

[0028] (4) After the reaction is complete, the resin is screened again through drum screen 3 to achieve solid-liquid separation. The waste liquid is collected and sent to the sewage treatment device. The regenerated resin is transferred to the stirred tank 4, 1000 kg of water is added, the stirring is turned on and the pH is adjusted to neutral by adding dilute hydrochloric acid, then washed twice with water. Finally, the regenerated resin is separated into solid and liquid by drum screen 14 and transferred back to the resin adsorption tank 1 by vacuum pump 6.

[0029] The content of organic matter in the resin before and after regeneration treatment was detected, and the specific results are shown in Table 1 below.

[0030] Table 1 - Changes in organic content of resin before and after regeneration treatment

[0031]

[0032] Example 3

[0033] In the apparatus of Example 1, the waste macroporous resin is regenerated. The waste resin mainly comes from the tail gas treatment device of the chemical industry. The organic matter adsorbed in the resin is mainly phenol and toluene, with a content of 18 kg / ton.

[0034] (1) Insert the feed pipe of vacuum pump 2 into the resin layer in resin adsorption tank 1, and use vacuum suction to extract the resin and transport it to drum screen 3. Each batch can process 1000 kg of wet waste resin.

[0035] (2) The drum screen 3 removes the resin powder through the rotating screen, and the resin with intact particles is screened out. The resin powder enters the sedimentation tank 7, and the resin with intact particles enters the mixing tank 4.

[0036] (3) Add 800 kg of water to the electric heating stirring tank, and add 60 kg of 99% ethanol, 30 kg of 32% liquid alkali, and 5 kg of tetrabutylammonium bromide (TBAB) phase transfer catalyst through the dosing device 5. Stir the resin for 4 to 5 hours under the alkaline high temperature environment of pH ≥ 11 and temperature of 80 ℃ to 95 ℃ and the action of the phase transfer catalyst to deeply remove macromolecular compounds and restore the resin adsorption capacity.

[0037] (4) After the reaction is complete, the resin is screened again through drum screen 3 to achieve solid-liquid separation. The waste liquid is collected and sent to the sewage treatment device. The regenerated resin is transferred to the stirred tank 4, 1000 kg of water is added, the stirring is turned on and the pH is adjusted to neutral by adding dilute hydrochloric acid, then washed twice with water. Finally, the regenerated resin is separated into solid and liquid by drum screen 14 and transferred back to the resin adsorption tank 1 by vacuum pump 6.

[0038] The content of organic matter in the resin before and after regeneration treatment was detected, and the specific results are shown in Table 2 below.

[0039] Table 2 - Changes in organic content of resin before and after regeneration treatment

[0040]

[0041] Example 4

[0042] In the apparatus of Example 1, the waste macroporous resin is regenerated. The waste resin comes from the tail gas treatment device of the chemical industry. The organic matter adsorbed in the resin is dibutylamine, triethylenetetramine, etc., with a content of 15 kg / ton.

[0043] (1) Insert the feed pipe of vacuum pump 2 into the resin layer in resin adsorption tank 1, and use vacuum suction to extract the resin and transport it to drum screen 3. Each batch can process 1000 kg of wet waste resin.

[0044] (2) The drum screen 3 removes the resin powder through the rotating screen, and the resin with intact particles is screened out. The resin powder enters the sedimentation tank 7, and the resin with intact particles enters the mixing tank 4.

[0045] (3) Add 800 kg of water to the electric heating stirring tank, and add 60 kg of 99% ethanol, 20 kg of 30% liquid alkali, and 5 kg of polyethylene glycol (PEG) phase transfer catalyst through the dosing device 5. Stir the resin for 4 to 5 hours under the acidic high temperature environment of pH ≤ 4 and temperature of 50 ℃ to 60 ℃ and the action of the phase transfer catalyst to deeply remove macromolecular compounds and restore the resin adsorption capacity.

[0046] (4) After the reaction is complete, the resin is screened again through drum screen 3 to achieve solid-liquid separation. The waste liquid is collected and sent to the sewage treatment device. The regenerated resin is transferred to the stirred tank 4, 1000 kg of water is added, the stirring is turned on and the pH is adjusted to neutral by adding dilute hydrochloric acid, then washed twice with water. Finally, the regenerated resin is separated into solid and liquid by drum screen 14 and transferred back to the resin adsorption tank 1 by vacuum pump 6.

[0047] The content of organic matter in the resin before and after regeneration treatment was detected, and the specific results are shown in Table 3 below.

[0048] Table 3 - Changes in organic content of resin before and after regeneration treatment

[0049]

[0050] Comparative Example 1

[0051] Comparative Example 1 uses a conventional high-temperature steam desorption method, with a temperature of 110 ℃~120 ℃, a desorption time of 2 hours, and two desorption cycles, to desorb and regenerate waste resin from exhaust gas treatment devices in the chemical and spraying industries. The organic matter adsorbed in the resin mainly consists of acrylic acids such as acrylonitrile, methyl methacrylate, ethyl acrylate, and butyl acrylate, with a content of 20 kg / ton.

[0052] The content of organic matter in the resin before and after regeneration treatment was detected, and the specific results are shown in Table 4 below.

[0053] Table 4 - Changes in organic content of resin before and after regeneration treatment

[0054]

[0055] As can be seen from the data in Table 4, if only high-temperature steam desorption is used, increasing the solubility of macromolecular organics by raising the eluent temperature still results in poor removal of macromolecular organics from the resin. Furthermore, the high temperature causes the resin to soften and expand under the action of high-temperature steam, generating microcracks that lead to resin breakage, thus increasing the loss rate.

[0056] Comparative Example 2

[0057] Comparative Example 2 uses the method of the present invention without using a phase transfer catalyst. In the apparatus of Example 1, the waste macroporous resin is regenerated. The waste resin mainly comes from the tail gas treatment device of the chemical industry. The organic matter adsorbed in the resin is mainly phenol and toluene, with a content of 18 kg / ton.

[0058] The content of organic matter in the resin before and after regeneration treatment was detected, and the specific results are shown in Table 5 below.

[0059] Table 5 - Changes in organic content of resin before and after regeneration treatment

[0060]

[0061] As shown in Table 5, the removal efficiency of macromolecular organic matter from the resin is poor without the addition of a phase transfer catalyst. This is because macromolecular organic matter is adsorbed within the network structure of the macroporous resin. Two types of adsorption exist between the macromolecular organic matter and the macroporous resin: hydrogen bonds and van der Waals forces. Although adjusting the pH of the washing solution with an alkaline solution can disrupt the hydrogen bonds between the macroporous resin and the adsorbed organic matter, the amount of alkaline solution added is limited, thus limiting the disruption of these bonds. Furthermore, macromolecular organic matter is highly polar, and ethanol alone has limited dissolution potential. Therefore, the combination of organic solvent and alkali is ineffective in removing macromolecular organic matter.

[0062] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A method for deep regeneration of macroporous resins adsorbed with exhaust gas, characterized by, The macroporous resin is regenerated by adding an organic solvent, an aqueous sodium hydroxide solution and a phase transfer catalyst to the resin to be regenerated, stirring and heating, and then separating the solid from the liquid, and washing the resin.

2. The method for deep regeneration of macroporous resin adsorbing waste gas according to claim 1, characterized in that, Before the organic solvent, the aqueous sodium hydroxide solution and the phase transfer catalyst are added, the resin to be regenerated is also sieved to remove broken resin powder from the resin to be regenerated.

3. The method of deep regeneration of macroporous resins for adsorbing exhaust gases according to claim 1, characterized in that, The washing includes adjusting the pH of the resin by using hydrochloric acid, and then washing the resin by using water until the ionization degree of the washing liquid meets the requirements.

4. The method for deep regeneration of macroporous resins adsorbed with waste gas according to claim 1, characterized in that, The phase transfer catalyst is used in an amount of 0.005-0.05 g / g based on the mass of the macroporous resin.

5. The method of deep regeneration of macroporous resins for adsorbing exhaust gases according to claim 1, characterized in that, The organic solvent is ethanol.

6. The method of deep regeneration of macroporous resins for adsorbing exhaust gases according to claim 1, characterized in that, The mass concentration of the aqueous sodium hydroxide solution is 1%-5%.

7. The method of deep regeneration of macroporous resins for adsorbing exhaust gases according to claim 2, characterized in that, The broken resin powder is collected and treated as solid waste after entering a sedimentation tank.

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