Deep regeneration method of macroporous resin for adsorbing waste gas

Abstract

The invention relates to a deep regeneration method of macroporous resin for adsorbing waste gas, and belongs to the technical field of resin regeneration. The regeneration method comprises the following steps: adding an organic solvent, a sodium hydroxide aqueous solution and a phase transfer catalyst into resin to be regenerated, heating, stirring, carrying out solid-liquid separation, and washing the resin to obtain regenerated macroporous resin. The organic solvent is used for eluting the adsorbate in the macroporous resin, and the phase transfer catalyst is used for promoting the separation of the macromolecular compound and the macroporous resin, so that the macromolecular compound which is difficult to remove by the organic solvent can be deeply removed, the resin can be deeply regenerated, and the service life of the resin is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of resin regeneration, and in particular to a method for deep regeneration of a macroporous resin for adsorbing waste gas. Background Art

[0002] Macroporous adsorption resins are a new type of polymer adsorption material that has rapidly developed in recent years. They possess a spatial network structure. They are characterized by a high degree of cross-linking, high porosity, and a large specific surface area. The pores within macroporous adsorption resins are three-dimensional. Compared to activated carbon, which is commonly used to adsorb organic waste gases, macroporous adsorption resins are spherical particles with low adsorption resistance and high adsorption rates. They are capable of not only surface adsorption but also skeletal 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 by high temperatures and damaged by friction, broken resin powder clogs the spaces between resin particles, affecting gas distribution and flow, and increasing the resistance of the adsorption tank. Furthermore, the exhaust gas composition is complex, and the accumulation of high-boiling-point, low-saturated vapor pressure macromolecules significantly reduces the efficiency of resin adsorption and desorption regeneration. To ensure the adsorption tank's adsorption capacity, resin loss must be regularly inspected and replenished. However, as resin powder and difficult-to-desorb components accumulate, the exhaust gas resin adsorption tank generally requires complete resin replacement every three to five years, depending on operating conditions.

[0004] Although macroporous adsorption resins have better adsorption capacity and regeneration ability than activated carbon and molecular sieves, the desorption of VOCs is different from that of resins used to treat wastewater. Resins in wastewater can be washed out with solvents, and desorption is generally performed by increasing the temperature. However, the temperature tolerance of macroporous adsorption resins is lower than that of activated carbon and molecular sieves. Especially under dry conditions, the pore structure of macroporous adsorption resins will change and may even break. Some macromolecular compounds with high boiling points and low saturated vapor pressures contained in exhaust gas are difficult to desorb after being adsorbed by the adsorption resin, which in turn causes poisoning of the adsorption resin. Although the content of these substances is not high, they are difficult to remove from the resin after being adsorbed, and thus accumulate in the resin, causing the adsorption resin to quickly become poisoned and ineffective. Summary of the Invention

[0005] Current macroporous resin adsorption devices typically utilize online steam desorption, which is subject to desorption temperature constraints and, during fixed-bed desorption, results in low desorption efficiency and incomplete desorption for macromolecular compounds with high boiling points and low saturated vapor pressures. The present invention provides a method for deep regeneration of waste gas-adsorbed macroporous resins to address these issues. The present invention achieves deep regeneration of the macroporous resin by screening the discarded macroporous resin and then using a phase transfer catalyst to thoroughly remove the macromolecular compounds with high boiling points and low saturated vapor pressures adsorbed within the macroporous resin.

[0006] The technical solution of the present invention is as follows: A method for deep regeneration of macroporous resin for adsorbing waste gas, comprising 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, then separating the solid from the liquid, washing the resin to obtain the regenerated macroporous resin; the phase transfer catalyst is one of quaternary ammonium salts, crown ethers or polyethers.

[0007] The specific steps are as follows: first screen the resin to be regenerated, sieve out the broken resin powder, and screen out the resin with intact particles; then transfer the screened resin with intact particles to a stirring kettle with stirring and heating functions, add an organic solvent, an aqueous sodium hydroxide solution, and a phase transfer catalyst, and remove the macromolecular compounds in the resin under heating conditions; after solid-liquid separation, adjust the pH of the resin with hydrochloric acid to promote the dissolution and washing of salts. Wash the resin with water until the ionization degree of the washing liquid meets the requirements to obtain the regenerated macroporous resin.

[0008] Further, 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; the dosage of the phase transfer catalyst is 0.005-0.05 g / g based on the mass of the macroporous resin.

[0009] Further, the organic solvent is ethanol.

[0010] Further, the mass concentration of the aqueous sodium hydroxide solution is 1% - 5%. The addition method of the aqueous sodium hydroxide solution can be to directly add the pre-prepared aqueous sodium hydroxide solution with a mass concentration of 1% - 5%, or to add solid sodium hydroxide and then dissolve it with water to obtain an aqueous sodium hydroxide solution with a mass concentration of 1% - 5%; of course, commercially available liquid alkali solution can also be used, and by diluting it with water, an aqueous sodium hydroxide solution with a mass concentration of 1% - 5% can be obtained.

[0011] Further, the resin powder sieved out after screening enters the sedimentation tank and is collected and treated as solid waste.

[0012] The above-mentioned method for deep regeneration of macroporous resin for adsorbing waste gas can be realized by a device with the following structure: The device includes a stirring kettle; the inlet of the stirring kettle is communicated with the residue outlet of the first rotary screen; the inlet of the first rotary screen is communicated with the resin adsorption tank through the first vacuum pump; the outlet of the stirring kettle is respectively communicated with the inlet of the first rotary screen and the inlet of the second rotary screen; the undersize outlet of the second rotary screen is communicated with the inlet of the stirring kettle; the residue outlet of the second rotary screen is communicated with the resin adsorption tank through the second vacuum pump; the inlet of the stirring kettle is further communicated with a dosing device, and the dosing device is respectively communicated with a solvent tank, a liquid caustic soda tank, a phase transfer catalyst tank and a hydrochloric acid tank. This device is integrally arranged, easy to operate and has high safety.

[0013] Further, the undersize outlet of the first rotary screen is communicated with a sedimentation tank; the sedimentation tank is communicated with a filter press through the third vacuum pump.

[0014] The beneficial effects of the present invention are as follows: The method for deep regeneration of macroporous resin for adsorbing waste gas provided by the present invention can deeply remove macromolecular compounds that are not easily removed by organic solvents by using an organic solvent to elute the adsorbates in the macroporous resin and using a phase transfer catalyst to promote the separation of macromolecular compounds from the macroporous resin, and can deeply regenerate the resin and extend the service life of the resin. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of the device for deep regeneration of macroporous resin for adsorbing waste gas in Embodiment 1 of the present invention.

[0017] In the figure, 1 - resin adsorption tank, 2 - first vacuum pump, 3 - first rotary screen, 4 - stirring kettle, 5 - dosing device, 6 - second vacuum pump, 7 - sedimentation tank, 8 - third vacuum pump, 9 - filter press, 10 - solvent tank, 11 - liquid caustic soda tank, 12 - phase transfer catalyst tank, 13 - hydrochloric acid tank, 14 - second rotary screen. Detailed Embodiments

[0018] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] Example 1 A device for deep regeneration of macroporous resin for adsorbing waste gas, including a stirring kettle 4, and the stirring kettle 4 is an electrically heated stirring kettle; the inlet of the stirring kettle 4 is communicated with the residue outlet of the first drum sieve 3; the inlet of the first drum sieve 3 is communicated with the resin adsorption tank 1 through a first vacuum pump 2, and the vacuum pump 2 is a diaphragm vacuum pump; the outlet of the stirring kettle 4 is respectively communicated with the inlet of the first drum sieve 3 and the inlet of the second drum sieve 14; the undersize outlet of the second drum sieve 14 is communicated with the inlet of the stirring kettle 4; the residue outlet of the second drum sieve 14 is communicated with the inlet of the resin adsorption tank 1 through a second vacuum pump 6; the inlet of the stirring kettle 4 is also communicated with a dosing device 5, and the dosing device 5 is respectively communicated with a solvent tank 10, a liquid caustic soda tank 11, a phase transfer catalyst tank 12 and a hydrochloric acid tank 13; the undersize outlet of the first drum sieve 3 is communicated with a sedimentation tank 7; the sedimentation tank 7 is communicated with a filter press 9 through a third vacuum pump 8.

[0020] Example 2 In the device of Example 1, the waste macroporous resin is regenerated. The waste resin is from the tail gas treatment devices in the chemical industry and spraying industry. The organic substances adsorbed in the resin are mainly 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: (1) Insert the feed pipeline of the first vacuum pump 2 into the resin layer in the resin adsorption tank 1, and draw out the resin by means of vacuum suction and transport it to the first drum sieve 3. Each batch can process 1000 kg of wet waste resin. (2) The first drum sieve 3 screens out the resin powder through a rolling sieve mesh, and selects the resin with intact particles. The resin powder enters the sedimentation tank 7, and the resin with intact particles enters the stirring kettle 4. (3) Add 800 kg of water to the electrically heated stirring kettle, and through the dosing device 5, add 50 kg of organic solvent 99% ethanol, 25 kg of 32% liquid caustic soda, and 5 kg of phase transfer catalyst tetrabutylammonium bromide (TBAB). Under the alkaline high-temperature environment with pH≥11 and temperature of 80 °C - 95 °C and the action of the phase transfer catalyst, stir and react the resin for 5 - 6 hours to deeply remove macromolecular compounds and restore the resin adsorption capacity. (4)After the reaction is completed, screening is carried out again through the rotary 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 stirring kettle 4, 1000 kg of water is added, stirring is started, and it is adjusted to neutral by adding dilute hydrochloric acid, then washed twice with water. Finally, the regenerated resin is separated by solid - liquid separation through the rotary screen two 14 and transferred back to the resin adsorption tank 1 through the vacuum pump two 6.

[0021] Detect the content of organic matter in the resin before and after the regeneration treatment. The specific results are shown in Table 1 below.

[0022] Table 1 - Changes in the content of organic matter in the resin before and after the regeneration treatment

[0023] Example 3 In the device of Example 1, the waste macroporous resin is regenerated. The waste resin mainly comes from the tail gas treatment device in the chemical industry. The organic matter adsorbed in the resin is mainly phenol and toluene, and the content is 18 kg / ton.

[0024] (1)Insert the feed pipeline of the vacuum pump one 2 into the resin layer in the resin adsorption tank 1, and draw out the resin by means of vacuum suction and transport it to the rotary screen one 3. Each batch can process 1000 kg of wet waste resin. (2)The rotary screen one 3 screens out the resin powder through the rolling screen mesh, selects the resin with intact particles, the resin powder enters the sedimentation tank 7, and the resin with intact particles enters the stirring kettle 4. (3)Add 800 kg of water to the electrically heated stirring kettle, and through the dosing device 5, add 60 kg of 99% ethanol as an organic solvent, 30 kg of 32% liquid caustic soda, and 5 kg of phase - transfer catalyst tetrabutylammonium bromide (TBAB). Under the alkaline high - temperature environment with pH≥11 and temperature 80 °C - 95 °C and the action of the phase - transfer catalyst, stir the resin for 4 - 5 hours to deeply remove macromolecular compounds and restore the resin adsorption capacity. (4)After the reaction is completed, screening is carried out again through the rotary screen one 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 stirring kettle 4, 1000 kg of water is added, stirring is started, and it is adjusted to neutral by adding dilute hydrochloric acid, then washed twice with water. Finally, the regenerated resin is separated by solid - liquid separation through the rotary screen two 14 and transferred back to the resin adsorption tank 1 through the vacuum pump two 6.

[0025] Detect the content of organic matter in the resin before and after the regeneration treatment. The specific results are shown in Table 2 below.

[0026] Table 2 - Changes in the content of organic matter in the resin before and after the regeneration treatment

[0027] Example 4 In the device of Example 1, the waste macroporous resin is regenerated. The waste resin is from the tail gas treatment device in the chemical industry. The organic substances adsorbed in the resin are dibutylamine, triethylenetetramine, etc., and the content is 15 kg / ton.

[0028] (1) Insert the feed pipe of vacuum pump 1 into the resin layer in resin adsorption tank 1, and draw out the resin by means of vacuum suction and transport it to rotary screen 1. Each batch can process 1000 kg of wet waste resin. (2) Rotary screen 1 screens out the resin powder through the rolling screen, and selects the resin with intact particles. The resin powder enters sedimentation tank 7, and the resin with intact particles enters stirring kettle 4. (3) Add 800 kg of water to the electrically heated stirring kettle. Through dosing device 5, add 60 kg of organic solvent 99% ethanol, 20 kg of 30% liquid caustic soda, and 5 kg of phase transfer catalyst polyethylene glycol (PEG). Under the acidic high-temperature environment with pH≤4 and temperature of 50 °C - 60 °C and the action of the phase transfer catalyst, stir and react the resin for 4 - 5 hours to deeply remove macromolecular compounds and restore the resin adsorption capacity. (4) After the reaction is completed, screen again through rotary screen 1 to achieve solid-liquid separation. The waste liquid is collected and sent to the sewage treatment device. The regenerated resin is transferred to stirring kettle 4, add 1000 kg of water, start stirring, adjust to neutral by adding dilute hydrochloric acid, then wash twice with water. Finally, after the solid-liquid separation of the regenerated resin through rotary screen 2, transfer and transport it back to resin adsorption tank 1 through vacuum pump 2.

[0029] Detect the content of organic substances in the resin before and after the regeneration treatment. The specific results are shown in Table 3 below.

[0030] Table 3 - Changes in the content of organic substances in the resin before and after the regeneration treatment

[0031] Comparative Example 1 Comparative Example 1 uses the existing general steam high-temperature desorption method, with the temperature at 110 °C - 120 °C, the desorption time is 2 hours, and desorb twice to desorb and regenerate the waste resin from the tail gas treatment devices in the chemical and spraying industries. The organic substances adsorbed in the resin are mainly acrylic acids such as acrylonitrile, methyl methacrylate, ethyl acrylate, butyl acrylate, etc., and the content is 20 kg / ton.

[0032] Detect the content of organic substances in the resin before and after the regeneration treatment. The specific results are shown in Table 4 below.

[0033] Table 4 - Changes in the content of organic substances in the resin before and after the regeneration treatment

[0034] As can be seen from the data in Table 4, if only the steam high-temperature desorption method is used, by increasing the temperature of the eluent to increase the solubility of macromolecular organic matter, the removal effect of macromolecular organic matter in the resin is still poor. And due to the high-temperature effect, the resin softens and swells under the action of high-temperature steam, generating tiny cracks and causing the resin to break, thus resulting in an increase in the loss rate.

[0035] Comparative Example 2 In Comparative Example 2, the method of the present invention was used without using a phase transfer catalyst. In the device of Example 1, waste macroporous resin was regenerated. The waste resin mainly came from the tail gas treatment device in the chemical industry. The organic matter adsorbed in the resin was mainly phenol and toluene, with a content of 18 kg / ton.

[0036] The content of organic matter in the resin before and after the regeneration treatment was detected, and the specific results are shown in Table 5 below.

[0037] Table 5 - Changes in the content of organic matter in the resin before and after the regeneration treatment

[0038] As can be seen from the data in Table 5, without adding a phase transfer catalyst, the removal effect of macromolecular organic matter in the resin is poor. This is because the macromolecular organic matter is adsorbed in the network structure of the macroporous resin. There are two types of adsorption between the macromolecular organic matter and the macroporous resin. One is the hydrogen bond formed between the two, and the other is the van der Waals force. Although the pH of the washing solution can be adjusted with alkali solution to break the hydrogen bond formed between the macroporous resin and the adsorbed organic matter, due to the limited amount of alkali solution added, the destruction of the hydrogen bond is also limited. And the polarity of the macromolecular organic matter is relatively strong, and the dissolution of the macromolecular organic matter by ethanol alone is limited. Therefore, the removal effect of macromolecular organic matter by using the method of organic solvent + alkali is poor.

[0039] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A method for deep regeneration of macroporous resin for adsorbing waste gas, characterized in that, An organic solvent, an aqueous sodium hydroxide solution and a phase transfer catalyst are added to the resin to be regenerated. After heating and stirring, solid-liquid separation is carried out. After washing the resin, the regenerated macroporous resin is obtained. The phase transfer catalyst is one of quaternary ammonium salts, crown ethers or polyethers.

2. The deep regeneration method of macroporous resin for adsorbing waste gas according to claim 1, characterized in that, Before adding the organic solvent, the aqueous sodium hydroxide solution and the phase transfer catalyst, the resin to be regenerated is also subjected to screening treatment to screen out the broken resin powder in the resin to be regenerated and select the resin with intact particles.

3. The deep regeneration method of macroporous resin for adsorbing waste gas according to claim 1, characterized in that, The washing includes adjusting the pH of the resin with hydrochloric acid; then washing the resin with water until the ionization degree of the washing liquid meets the requirements.

4. A method for deep regeneration of macroporous resin for adsorbing waste gas according to any one of claims 1-3, characterized in that, The quaternary ammonium salt is one of tetrabutylammonium bromide, tetrabutylammonium chloride or benzyltriethylammonium chloride; the crown ether is one of 15-crown-5, 18-crown-6 or dibenzo-18-crown-6; the polyether is one of polyethylene glycol, polypropylene glycol or polyethylene glycol-polypropylene glycol block copolymer.

5. The method for deep regeneration of macroporous resin for adsorbing waste gas according to claim 4, characterized in that, The dosage of the phase transfer catalyst is 0.005~0.05 g / g based on the mass of the macroporous resin.

6. The deep regeneration method of macroporous resin for adsorbing waste gas according to claim 1, wherein, The organic solvent is ethanol.

7. The deep regeneration method of macroporous resin for adsorbing waste gas according to claim 1, characterized in that, The mass concentration of the aqueous sodium hydroxide solution is 1%~5%.

8. The method for deep regeneration of macroporous resin for adsorbing waste gas according to claim 2, characterized in that, The broken resin powder enters the sedimentation tank and is collected and treated as solid waste.

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