Regeneration method of deactivated Mn-based catalyst for removing VOCs

Abstract

The present invention provides a regeneration method for a deactivated Mn-based catalyst for removing VOCs, the method comprising the following steps: step (1), mixing and stirring the deactivated Mn-based catalyst and a desulfurization solvent A to form a mixed slurry B; step (2), filtering the mixed slurry B to obtain a solid C and a washing liquid D; step (3), subjecting the solid C and potassium permanganate to an oxidation reaction in deionized water to obtain a solid E; step (4), calcining the solid E in an oxygen-containing atmosphere to obtain a regenerated Mn-based catalyst. By applying the regeneration method for a deactivated Mn-based catalyst for removing VOCs provided by the present invention, the active components in the regenerated Mn-based catalyst can be well restored. Moreover, the regeneration method provided by the present invention has low raw material cost and is easy to operate, and there is no secondary pollution of wastewater and waste gas during the regeneration process, which effectively solves the regeneration problem of the deactivated Mn-based catalyst caused by the simultaneous influence of carbon and sulfur in the fermentation industry.

Description

Technical Field

[0001] The present invention relates to the technical field of waste catalyst regeneration, and in particular provides a method for regenerating a deactivated Mn-based catalyst for removing VOCs. Background Art

[0002] The biological fermentation process will emit a large amount of volatile organic compounds (VOCs), such as carbon-containing or sulfur-containing VOCs. In order to reduce the impact of fermentation gases on the surrounding environment, the discharged fermentation gases need to be purified. Currently commonly used VOCs removers include metal oxides, carbon-based materials, liquid phase absorbents, etc. Among them, Mn-based catalysts containing manganese oxides, such as hydrotalcite-like catalysts loaded with manganese oxide, carbon-based core-shell catalysts loaded with manganese oxide, etc., have the advantages of low cost, good stability, and storage and oxygen release performance, and are commonly used VOCs removal catalysts.

[0003] During the VOCs catalytic removal process, CO 2 , H 2 O, H 2 S and other gaseous products, in the presence of oxygen and H 2 Under the further action of O, sulfur-containing compounds and carbon-containing compounds, such as elemental sulfur and carbonates, will be produced and covered on the catalyst surface, resulting in catalyst deactivation. Directly replacing the catalyst will increase the cost of VOCs purification, and the treatment and disposal of deactivated catalysts is also a difficult problem. Therefore, regenerating the deactivated catalyst is the key to solving the above problems.

[0004] Chinese patent CN202410023943.X discloses a "desulfurization catalyst regeneration method and a desulfurization catalyst regeneration liquid resource recovery method". This method uses multiple alkali washing and water washing methods to regenerate the desulfurization catalyst, and treats the leaching liquid with ferrous sulfate, quicklime and oxygen to obtain calcium sulfate and alkaline solution. Although this method can separate sulfur-containing substances on the catalyst, it cannot be used for catalysts that contain both carbon and sulfur deactivation; in addition, the process of resource recovery of the regeneration liquid generated by this method is complicated, and the economic added value of the calcium sulfate generated is low.

[0005] Chinese patent CN202310755892.5 discloses a “regeneration method and regeneration solution for deactivated manganese-based catalysts”. The method places the deactivated catalyst into a regeneration solution composed of persulfate, potassium permanganate and sulfate for regeneration treatment, thereby achieving the goal of regenerating the MnSO 4 Converted to MnO 2 Although this method provides a method for restoring the activity of the Mn-based catalyst, the regeneration method of the deactivated manganese-based catalyst disclosed in the patent is aimed at the active center MnO xThe reaction generates manganese sulfate which has no catalytic activity, causing the catalyst to be deactivated; however, the deactivation of Mn-based catalysts after VOCs gas purification in the fermentation industry is mainly due to the fact that solid compounds such as elemental sulfur and carbonates generated on the surface during the VOCs gas purification process cover the active centers, causing the catalyst to be deactivated. Therefore, this method is not suitable for the regeneration of Mn-based catalysts used to purify VOCs in the fermentation industry.

[0006] At present, there is no report on the technical method for regenerating the Mn-based catalyst deactivated by sulfur and carbon in the fermentation industry. Therefore, those skilled in the art are in urgent need of finding an effective regeneration method for the Mn-based catalyst used for purifying VOCs in the fermentation industry to meet the needs of the industry. Summary of the invention

[0007] The main purpose of the present invention is to provide a method for regenerating a deactivated Mn-based catalyst for removing VOCs, so as to solve the problem of regenerating the deactivated Mn-based catalyst caused by the simultaneous influence of carbon and sulfur in the fermentation industry in the prior art.

[0008] In order to achieve the above-mentioned object, the present invention provides a method for regenerating a deactivated Mn-based catalyst for removing VOCs, the method comprising the following steps: step (1), mixing and stirring the deactivated Mn-based catalyst and a desulfurization solvent A to form a mixed slurry B; step (2), filtering the mixed slurry B to obtain a solid C and a washing liquid D; step (3), subjecting the solid C to an oxidation reaction with potassium permanganate in deionized water to obtain a solid E; step (4), calcining the solid E in an oxygen-containing atmosphere to obtain a regenerated Mn-based catalyst.

[0009] Further, in step (1), the desulfurization solvent A comprises a first solvent, and the first solvent is C 1 ~C 5 alcohol solvent; preferably, the first solvent is one or more of methanol, ethanol, propanol and ethylene glycol; more preferably, the first solvent is a mixture of methanol and ethanol.

[0010] Furthermore, in step (1), the desulfurization solvent A also includes a second solvent, and the second solvent is carbon disulfide and / or DMF; preferably, the mass ratio of the first solvent to the second solvent in the desulfurization solvent A is (1-10):1; more preferably, the desulfurization solvent A is a mixture of ethanol and carbon disulfide in a mass ratio of (1-3):1, or a mixture of ethanol and DMF in a mass ratio of (5-8):1.

[0011] Furthermore, in step (1), the mass ratio of the deactivated Mn-based catalyst to the desulfurization solvent A is 1:(3-8); preferably, the mixed deactivated Mn-based catalyst and the desulfurization solvent A are stirred under ultrasonic conditions; more preferably, the ultrasonic stirring time is 10-30 min, and the ultrasonic stirring temperature is 25-45°C.

[0012] Furthermore, after the mixed slurry B is filtered, step (2) further comprises the step of washing the solid C with anhydrous ethanol; preferably, the mass of the anhydrous ethanol used for washing is 3 to 5 times the mass of the deactivated Mn-based catalyst.

[0013] Furthermore, in step (3), the mass ratio of solid C, potassium permanganate and deionized water is 1:(0.05-0.2):(3-8); preferably, the oxidation reaction time is 0.5-1.5h.

[0014] Furthermore, after the oxidation reaction is completed, step (3) further comprises: filtering and drying the product after the oxidation reaction in sequence to obtain solid E; preferably, the drying temperature is 85 to 105° C., and the drying time is 9 to 15 hours.

[0015] Furthermore, in step (4), the oxygen-containing atmosphere is an oxygen-containing atmosphere with an oxygen content of 40 to 55 vol%, preferably oxygen-enriched air with an oxygen content of 40 to 55 vol%, or an oxygen / nitrogen mixture with an oxygen content of 40 to 55 vol%; more preferably, the roasting temperature during the roasting process is 400 to 700°C, and the roasting time is 1 to 4 hours; further preferably, the solid E is placed in a tubular furnace for roasting.

[0016] Furthermore, the regeneration method of the deactivated Mn-based catalyst for removing VOCs in the present invention further comprises: recovering the washing liquid D by distillation to obtain a recovered solvent, and returning at least part of the recovered solvent to step (1) for recycling as the desulfurization solvent A; preferably, the distillation temperature in the distillation is 160-170° C.; preferably, the sulfur liquid remaining after the distillation is collected and cooled to obtain solid elemental sulfur.

[0017] According to another aspect of the present invention, a regenerated Mn-based catalyst is prepared by the regeneration method of a deactivated Mn-based catalyst for removing VOCs provided by the present invention. The catalytic activity of the regenerated Mn-based catalyst in purifying VOCs during fermentation is more than 83% of the catalytic activity of a fresh Mn-based catalyst.

[0018] By using a regeneration method for a deactivated Mn-based catalyst for removing VOCs provided by the present invention, the metal oxide active components in the regenerated Mn-based catalyst can be well restored. Moreover, the regeneration method provided by the present invention has low raw material cost and convenient operation, and there is no secondary pollution of waste water and waste gas during the regeneration process, which effectively solves the regeneration problem of the deactivated Mn-based catalyst caused by the simultaneous influence of carbon and sulfur in the fermentation industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic diagram showing the ethanol removal rate of the catalysts in Examples 1 to 17 and Comparative Examples 1 to 3 is shown;

[0021] Figure 2 A schematic diagram showing the acetaldehyde removal rate of the catalysts in Examples 1 to 17 and Comparative Examples 1 to 3 is shown;

[0022] Figure 3 A schematic diagram of the removal rate of diethyl sulfide by the catalysts in Examples 1 to 17 and Comparative Examples 1 to 3 is shown. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] As analyzed in the background technology section of the present application, a large amount of deactivated Mn-based catalysts will be generated in the process of treating and emitting a large amount of volatile organic compounds (VOCs) during the biological fermentation process. Direct replacement of the deactivated catalyst will increase the purification cost of VOCs on the one hand, and on the other hand, it is also a difficult problem for its treatment and disposal. In order to solve this problem, the present invention provides a regeneration method for deactivated Mn-based catalysts for removing VOCs, the method comprising the following steps: step (1), mixing and stirring the deactivated Mn-based catalyst and a desulfurization solvent A to form a mixed slurry B; step (2), filtering the mixed slurry B to obtain a solid C and a washing liquid D; step (3), oxidizing the solid C and potassium permanganate in deionized water to obtain a solid E; step (4), calcining the solid E in an oxygen-containing atmosphere to obtain a regenerated Mn-based catalyst.

[0025] Unlike deactivated catalysts in other fields, the surface components of Mn-based catalysts for purifying VOCs during the fermentation process are complex, and there are residual sulfur-containing substances (mostly elemental sulfur, a small amount of sulfide) and carbonates, etc., and the active ingredient manganese oxide is also partially deactivated during the treatment process to form manganese sulfate and manganese sulfide. Using traditional regeneration methods, it is impossible to completely remove these residues and restore the activity of manganese oxide. Unlike traditional regeneration methods, the present invention successively performs desulfurization, oxidation and decarbonization steps on the deactivated Mn-based catalyst. Through the above steps, the solid impurities such as elemental sulfur and carbonates remaining on the surface of the Mn-based catalyst deactivated due to the removal of VOCs can be effectively removed, and the manganese oxide reduced to a low-valent state can be oxidized and restored to MnO 2 , further restoring the activity of the catalyst.

[0026] In particular, the present invention first mixes and stirs the deactivated Mn-based catalyst and the desulfurization solvent A to form a mixed slurry B, and then filters the mixed slurry B to obtain a solid C and a washing liquid D. The desulfurization solvent A used in this step can fully dissolve the sulfur-containing substances on the surface of the deactivated Mn-based catalyst and rinse and separate the desulfurized catalyst (solid C). After desulfurization, the present invention further performs an oxidation reaction on the solid C and potassium permanganate in deionized water. In this process, potassium permanganate plays an oxidizing role and can oxidize the manganese oxide reduced to a low-valent state in the catalytic process into MnO 2 Finally, the present invention calcines the solid E in an oxygen-containing atmosphere, and by calcining under oxygen-rich conditions, the carbonate remaining on the catalyst surface during the catalytic process can be decomposed into CO 2 and metal oxides, thereby further restoring the activity of the catalyst.

[0027] It is worth mentioning that the present invention adopts a specific sequence in the desulfurization, oxidation and decarbonization process. Considering that the surface of the deactivated Mn-based catalyst is covered with a large amount of sulfur-containing substances, the present invention puts the desulfurization treatment in the first step, which can expose most of the catalyst surface and prepare for subsequent oxidation and decarbonization. Moreover, the use of solvent desulfurization and the operation of desulfurization first also avoid the problem of sulfur-containing gas pollution caused by direct roasting. Secondly, potassium permanganate is used to oxidize and recover MnO 2 , which avoids the influence of metal salts generated during the carbon removal process on manganese oxides on the catalyst surface. In addition, potassium permanganate, as a common oxidant, has the advantages of high oxidation stability and more thorough oxidation during use. However, compared with other commonly used oxidants, such as persulfates, it will produce byproducts such as sulfates and elemental sulfur during the oxidation process, and will introduce more sulfur-containing components. Therefore, the selection of potassium permanganate as an oxidant for use in the present invention is based on the above considerations. The active ingredient MnO after oxidation 2It is relatively stable and maintains good stability in the carbon removal step. Therefore, the above-mentioned specific sequence of the present invention can better ensure the regeneration effect of the deactivated Mn-based catalyst, and the regeneration process is simple and more environmentally friendly.

[0028] The desulfurization solvent A can be selected from a solvent having good solubility for sulfur-containing substances, especially sulfur. In order to improve the desulfurization effect, the desulfurization solvent is explored. In a preferred embodiment, the desulfurization solvent A in step (1) of the method comprises a first solvent, and the first solvent is C 1 ~C 5 Alcohol solvents. As a protic organic solvent, alcohol solvents have the advantages of good solubility, low toxicity, easy access, and low price for sulfur-containing substances, especially elemental sulfur. 1 ~C 5 The alcohol solvent has the characteristic of low boiling point. As one of the desulfurization solvents, it can effectively remove the elemental sulfur and sulfur-containing substances produced on the surface of the deactivated Mn-based catalyst due to the removal of VOCs. At the same time, the low-boiling point alcohol solvent is also conducive to subsequent recycling and reuse. More preferably, the first solvent is one or more of methanol, ethanol, propanol and ethylene glycol; further preferably, the first solvent is a mixture of methanol and ethanol. The use of the above-mentioned type of alcohol solvent has a better desulfurization effect.

[0029] Furthermore, the desulfurization solvent A in step (1) of the above method also includes a second solvent, and the second solvent is carbon disulfide and / or DMF. Carbon disulfide and DMF are good aprotic organic solvents. On the one hand, they are well compatible with the alcohol solvent of the first solvent, and on the other hand, they also have good solubility for elemental sulfur. By mixing the first solvent and the second solvent, the dissolution of elemental sulfur produced on the surface of the deactivated Mn-based catalyst caused by the removal of VOCs can be further improved. Preferably, the mass ratio of the first solvent to the second solvent in the desulfurization solvent A is (1 to 10): 1; more preferably, the desulfurization solvent A is a mixture of ethanol and carbon disulfide in a mass ratio of (1 to 3): 1, or a mixture of ethanol and DMF in a mass ratio of (5 to 8): 1. Using the above mixed solvent as the desulfurization solvent can achieve a better desulfurization effect.

[0030] Furthermore, in a preferred embodiment, the mass ratio of the deactivated Mn-based catalyst to the desulfurization solvent A in step (1) is 1:(3-8). The desulfurization solvent A plays a role in dissolving the residual sulfur-containing substances on the surface of the deactivated Mn-based catalyst during the operation. By adjusting the mass ratio of the deactivated Mn-based catalyst to the desulfurization solvent A, the mass ratio is controlled within a suitable range, which can not only dissolve more effectively but also reduce excessive use of the solvent, thereby achieving the purpose of cost saving. Preferably, the mixed deactivated Mn-based catalyst and the desulfurization solvent A are stirred under ultrasonic conditions; more preferably, the ultrasonic stirring time is 10-30 minutes and the ultrasonic stirring temperature is 25-45°C. Stirring ultrasound and appropriate heating help the sulfur-containing substances covering the surface of the deactivated Mn-based catalyst to be fully desorbed and dissolved in the desulfurization solvent A. The above operating conditions are conducive to achieving better desulfurization effects.

[0031] In a preferred embodiment, after obtaining the mixed slurry B to be filtered in step (2), a step of washing the solid C with anhydrous ethanol is also included. The solid part in the mixed slurry B is the Mn-based catalyst that has undergone the desulfurization process; the liquid part is a solution in which sulfur-containing substances are dissolved. By filtering and washing the Mn-based catalyst that has undergone the desulfurization operation with anhydrous ethanol, the solvent and sulfur-containing substances involved in the desulfurization attached to the surface can be removed. Preferably, the mass of anhydrous ethanol used for washing is 3 to 5 times the mass of the deactivated Mn-based catalyst. Using the above ratio can achieve a better washing effect.

[0032] After the desulfurization process, the present invention further utilizes the oxidizing property of potassium permanganate to oxidize the manganese oxide reduced to a low-valent state during the catalytic process into MnO 2 Thereby better restoring the activity. In order to more fully activate and regenerate, in a preferred embodiment, in step (3), the mass ratio of solid C, potassium permanganate and deionized water is 1: (0.05-0.2): (3-8); in addition to being covered with sulfur-containing substances and carbonates that affect the activity of the catalyst, the surface of the Mn-based catalyst deactivated by VOCs will also be reduced to a low-valent state. Manganese oxides will also affect the activity of the catalyst. Therefore, by utilizing the good oxidation performance of potassium permanganate, the manganese oxides reduced to a low-valent state are oxidized to MnO under the oxidation action of potassium permanganate. 2 , thereby further restoring the activity of the catalyst. Controlling the amount of potassium permanganate within the above range is more conducive to full activation. Preferably, when the oxidation reaction time is 0.5 to 1.5 hours, a better oxidation effect can be achieved.

[0033] Furthermore, after the oxidation reaction is completed, step (3) further comprises: filtering and drying the product after the oxidation reaction in sequence to obtain solid E. The fully dried product is in a good state, that is, the sulfur element covering the surface of the deactivated catalyst is removed and the catalytic activity of the manganese oxide reduced to a low-valent state in the deactivated catalyst is restored. Preferably, the drying temperature is 85 to 105° C. and the drying time is 9 to 15 hours. The above conditions can achieve the effect of full drying.

[0034] In order to further remove the carbonates remaining on the catalyst surface, in a preferred embodiment, in step (4), the solid E is calcined in an oxygen-containing atmosphere, and the oxygen-containing atmosphere is an oxygen-containing atmosphere with an oxygen content of 40 to 55 vol%, preferably oxygen-enriched air with an oxygen content of 40 to 55 vol%, or an oxygen / nitrogen mixture with an oxygen content of 40 to 55 vol%. Carbonates are easily decomposed at high temperatures, especially alkali metal carbonates, which will directly vaporize during the heating process. The surface of the catalyst treated by the above-mentioned desulfurization and oxidation steps still has residual carbonates that affect the activity of the catalyst. Therefore, after the high-temperature baking process under oxygen-rich conditions, the carbonates can be decomposed into CO 2 and metal oxides or directly vaporize to remove carbonates covering the catalyst surface, further restoring the catalytic activity of the catalyst. Preferably, the calcination temperature during the calcination process is 400-700°C, and the calcination time is 1-4 hours; further preferably, the solid E is placed in a tubular furnace for calcination. The above calcination conditions can effectively remove carbonates remaining on the catalyst surface, thereby further improving the catalytic efficiency of the catalyst.

[0035] In the regeneration method for deactivated Mn-based catalyst for removing VOCs provided by the present invention, the obtained washing liquid D is mostly desulfurization solvent A, and sulfur-containing substances and some other inevitable impurities are dissolved. In a preferred embodiment, the washing liquid D is recovered by distillation to obtain a recovered solvent, and at least part of the recovered solvent is returned to step (1) for recycling as desulfurization solvent A. The main component of desulfurization solvent A is the above-mentioned C 1 ~C 5 The alcohol solvent, carbon disulfide and / or DMF has the characteristics of low boiling point and easy recovery. By distilling, the desulfurization solvent is recovered, which can effectively save the cost of catalyst regeneration. Preferably, the distillation temperature in the distillation is 160-170°C; at the above temperature, at least part of the recovered solvent can be returned to step (1) for recycling as desulfurization solvent A.

[0036] Furthermore, the sulfur liquid remaining after distillation is collected and cooled to obtain solid elemental sulfur, which can generate additional economic added value.

[0037] According to another aspect of the present invention, a regenerated Mn-based catalyst for removing VOCs obtained by the above-mentioned regeneration method is also provided. After regeneration treatment, the VOCs catalytic activity can reach more than 83% of the fresh catalyst, which greatly solves the problem of recycling Mn-based catalysts for VOCs purification during the fermentation process.

[0038] From the above description, it can be seen that the present invention achieves the following technical effects: (1) The metal oxide active components in the regenerated Mn-based catalyst of the present invention can be well restored, and the VOCs catalytic activity of the regenerated catalyst can reach more than 83% of that of the fresh catalyst; (2) The regeneration method has low raw material cost and can be recycled and reused, and is easy to operate, and there is no secondary pollution of wastewater and waste gas during the regeneration process; (3) The sulfur after regeneration can be recycled and reused, which can generate economic added value. Therefore, the regeneration method of the deactivated Mn-based catalyst for removing VOCs provided by the present invention effectively solves the regeneration problem of the Mn-based catalyst deactivated by both carbon and sulfur in the fermentation industry.

[0039] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0040] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0041] It should be noted that:

[0042] The deactivated Mn-based catalyst used in the examples is a used and deactivated hydrotalcite-like catalyst loaded with manganese oxide, the surface of which mainly contains elemental sulfur, manganese sulfate and manganese carbonate.

[0043] In the embodiments, the removal activity of the catalyst is represented by the removal rate of a certain component, wherein the catalytic effect of the catalyst is represented by the total time required for the removal efficiency of a certain component to reach 100%. In the embodiments of the present invention, the removal rate and removal effect of the regenerated catalyst on ethanol, acetaldehyde and diethyl sulfide are mainly tested and compared with the fresh catalyst.

[0044] The calculation method of the regeneration performance of the regenerated catalyst relative to the fresh catalyst in the embodiment is: the ratio of the time when the three gases of the regenerated catalyst reach 95% removal rate to the time corresponding to the fresh catalyst, and the final regeneration performance takes the lowest one among the three ratios.

[0045] Example 1

[0046] 10g of deactivated Mn-based catalyst, 15g of anhydrous ethanol (first solvent), and 15g of carbon disulfide (second solvent) were mixed and ultrasonically stirred at 35°C for 30min to form a mixed slurry B. The mixed slurry B was filtered and washed with 30g of anhydrous ethanol to obtain solid C and washing liquid D. Solid C, potassium permanganate and deionized water were mixed in a mass ratio of 1:0.2:3 and stirred at room temperature for 0.5h. After filtering, the solid was placed in a blast drying oven and dried at 105°C for 12h to obtain solid E. The dried solid E was placed in a tubular furnace and calcined at 550°C for 4h in an oxygen-rich atmosphere composed of oxygen + air (oxygen content 45vol%) to obtain a regenerated Mn-based catalyst. In addition, the washing liquid D was distilled and recovered at 160°C to obtain a regenerated solvent A, which can be used for recycling.

[0047] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 390 min, a 100% acetaldehyde removal rate of 450 min, and a 100% ethyl sulfide removal rate of 360 min, and the regeneration performance reached 99% of the fresh catalyst.

[0048] Example 2

[0049] 10g of deactivated Mn-based catalyst, 70g of anhydrous ethanol (first solvent), and 10g of DMF (second solvent) were mixed and ultrasonically stirred at 25°C for 15min to form a mixed slurry B. The mixed slurry B was filtered and washed with 50g of anhydrous ethanol to obtain solid C and washing liquid D. Solid C, potassium permanganate and deionized water were mixed in a mass ratio of 1:0.1:6 and stirred at room temperature for 1.2h. After filtering, the solid was placed in a blast drying oven and dried at 90°C for 9h to obtain solid E. The dried solid E was placed in a tubular furnace and calcined at 400°C for 2h in an oxygen-rich atmosphere composed of oxygen + nitrogen (oxygen content 55vol%) to obtain a regenerated Mn-based catalyst. In addition, the washing liquid D was distilled and recovered at 170°C to obtain a regenerated solvent A, which can be used for recycling.

[0050] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst had a 100% ethanol removal rate of 360 min, a 100% acetaldehyde removal rate of 420 min, and a 100% ethyl sulfide removal rate of 330 min, and the regeneration performance reached 97% of the fresh catalyst.

[0051] Example 3

[0052] 10g of deactivated Mn-based catalyst, 50g of anhydrous ethanol (first solvent), and 5g of methanol (first solvent) were mixed and ultrasonically stirred at 45°C for 10min to form a mixed slurry B. The mixed slurry B was filtered and washed with 40g of anhydrous ethanol to obtain solid C and washing liquid D. Solid C, potassium permanganate and deionized water were mixed in a mass ratio of 1:0.05:8 and stirred at room temperature for 1h. After filtering, the solid was placed in a blast drying oven and dried at 85°C for 15h to obtain solid E. The dried solid E was placed in a tubular furnace and calcined at 700°C for 1h in an oxygen-rich atmosphere composed of oxygen + air (oxygen content 40vol%) to obtain a regenerated Mn-based catalyst. In addition, the washing liquid D was distilled and recovered at 165°C to obtain a regenerated solvent A, which can be used for recycling.

[0053] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 330 min, a 100% acetaldehyde removal rate of 390 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reached 95% of the fresh catalyst.

[0054] Example 4

[0055] The difference from Example 1 is that the first solvent is ethanol, and the second solvent is not used.

[0056] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 330 min, a 100% acetaldehyde removal rate of 360 min, and a 100% ethyl sulfide removal rate of 270 min, and the regeneration performance reached 84% of the fresh catalyst.

[0057] Example 5

[0058] The difference from Example 3 is that ethanol is replaced by propanol.

[0059] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1, reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst had a 100% ethanol removal rate of 330 min, a 100% acetaldehyde removal rate of 360 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reached 91% of the fresh catalyst.

[0060] Example 6

[0061] The difference from Example 1 is that the mass ratio of the first solvent to the second solvent is 10:1.

[0062] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 390 min, a 100% acetaldehyde removal rate of 420 min, and a 100% ethyl sulfide removal rate of 330 min, and the regeneration performance reached 97% of the fresh catalyst.

[0063] Example 7

[0064] The difference from Example 1 is that the ratio of the first solvent to the second solvent is 15:1.

[0065] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 330 min, a 100% acetaldehyde removal rate of 390 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reached 86% of the fresh catalyst.

[0066] Example 8

[0067] The difference from Example 1 is that the mass ratio of ethanol to carbon disulfide is 3:1.

[0068] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst had a 100% ethanol removal rate of 390 min, a 100% acetaldehyde removal rate of 420 min, and a 100% ethyl sulfide removal rate of 360 min, and the regeneration performance reached 98% of the fresh catalyst.

[0069] Example 9

[0070] The difference from Example 2 is that the mass ratio of ethanol to DMF is 5:1.

[0071] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 360 min, a 100% acetaldehyde removal rate of 390 min, and a 100% ethyl sulfide removal rate of 330 min, and the regeneration performance reached 95% of the fresh catalyst.

[0072] Example 10

[0073] The difference from Example 2 is that the mass ratio of ethanol to DMF is 8:1.

[0074] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst had a 100% ethanol removal rate of 360 min, a 100% acetaldehyde removal rate of 420 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reached 96% of the fresh catalyst.

[0075] Embodiment 11

[0076] The difference from Example 2 is that the mass ratio of ethanol to DMF is 10:1.

[0077] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 360 min, a 100% acetaldehyde removal rate of 390 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reached 92% of the fresh catalyst.

[0078] Example 12

[0079] The difference from Example 1 is that the mass ratio of solid C, potassium permanganate and deionized water is 1:0.05:3.

[0080] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 390 min, a 100% acetaldehyde removal rate of 420 min, and a 100% ethyl sulfide removal rate of 360 min, and the regeneration performance reached 97% of the fresh catalyst.

[0081] Example 13

[0082] The difference from Example 1 is that the stirring time of the oxidation reaction is 1.5 h.

[0083] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst had a 100% ethanol removal rate of 390 min, a 100% acetaldehyde removal rate of 450 min, and a 100% ethyl sulfide removal rate of 360 min, and the regeneration performance reached 98% of the fresh catalyst.

[0084] Embodiment 14

[0085] The difference from Example 1 is that the calcination temperature is 700°C.

[0086] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 390 min, a 100% acetaldehyde removal rate of 420 min, and a 100% ethyl sulfide removal rate of 360 min, and the regeneration performance reached 97% of the fresh catalyst.

[0087] Embodiment 15

[0088] The difference from Example 1 is that the calcination temperature is 350°C.

[0089] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1, reaction temperature 325° C. After testing, 2 g of the regenerated Mn-based catalyst obtained above had a 100% ethanol removal rate of 330 min, a 100% acetaldehyde removal rate of 390 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reached 83% of the fresh catalyst.

[0090] Example 16

[0091] The difference from Example 1 is that the roasting condition in step (4) is air.

[0092] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst has a 100% ethanol removal rate of 360 min, a 100% acetaldehyde removal rate of 390 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance reaches 90% of the fresh catalyst.

[0093] Embodiment 17

[0094] The difference from Example 1 is that the catalyst tested is a fresh catalyst.

[0095] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. According to the test, 2 g of the above fresh Mn-based catalyst has a 100% ethanol removal rate of 420 min, a 100% acetaldehyde removal rate of 450 min, and a 100% ethyl sulfide removal rate of 360 min.

[0096] Comparative Example 1

[0097] 10g of deactivated Mn-based catalyst, potassium permanganate and deionized water were mixed in a mass ratio of 1:0.15:5 and stirred at room temperature for 1.2h. After filtering, the solid was placed in a forced air drying oven and dried at 100°C for 13h to obtain solid E. The dried solid E was placed in a tubular furnace and calcined at 600°C for 3h in an oxygen-rich atmosphere composed of oxygen + air (oxygen content 50vol%) to obtain a regenerated Mn-based catalyst.

[0098] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1, reaction temperature 325° C. 2 g of the above-obtained regenerated Mn-based catalyst has a 100% ethanol removal rate of 270 min, a 100% acetaldehyde removal rate of 300 min, and a 100% ethyl sulfide removal rate of 240 min, and the regeneration performance can only reach 61% of the fresh catalyst.

[0099] Comparative Example 2

[0100] 10g of deactivated Mn-based catalyst, 25g of anhydrous ethanol (first solvent), and 5g of DMF (second solvent) were mixed and ultrasonically stirred at 30°C for 25min to form a mixed slurry B. The mixed slurry B was filtered and washed with 45g of anhydrous ethanol to obtain solid C and washing liquid D. Solid C, potassium permanganate and deionized water were mixed in a mass ratio of 1:0.1:4 and stirred at room temperature for 1.5h. After filtering, the solid was placed in a blast drying oven and dried at 90°C for 11h to obtain a regenerated Mn-based catalyst. In addition, the washing liquid D was distilled and recovered at 165°C to obtain a regenerated solvent A, which can be used for recycling.

[0101] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1 , reaction temperature 325° C. 2 g of the above-obtained regenerated Mn-based catalyst has a 100% ethanol removal rate of 330 min, a 100% acetaldehyde removal rate of 360 min, and a 100% ethyl sulfide removal rate of 300 min, and the regeneration performance can only reach 73% of the fresh catalyst.

[0102] Comparative Example 3

[0103] 10g of deactivated Mn-based catalyst, 15g of anhydrous ethanol (first solvent), and 15g of carbon disulfide (second solvent) were mixed and ultrasonically stirred at 35°C for 30min to form a mixed slurry B. The mixed slurry B was filtered and washed with 30g of anhydrous ethanol to obtain solid C and washing liquid D. Solid C was placed in a blast drying oven and dried at 105°C for 12h to obtain solid E. The dried solid E was placed in a tubular furnace and calcined at 550°C for 4h in an oxygen-rich atmosphere composed of oxygen + air (oxygen content 45vol%) to obtain a regenerated Mn-based catalyst. In addition, the washing liquid D was distilled and recovered at 160°C to obtain a regenerated solvent A, which can be used for recycling.

[0104] The activity test of the catalyst was carried out in a fixed bed quartz reactor. The reaction conditions were: ethanol concentration 1200ppm, acetaldehyde concentration 400ppm, diethyl sulfide concentration 400ppm, space velocity 20000h -1, reaction temperature 325° C. After testing, 2 g of the above-obtained regenerated Mn-based catalyst had a 100% ethanol removal rate of 240 min, a 100% acetaldehyde removal rate of 210 min, and a 100% ethyl sulfide removal rate of 210 min, and the regeneration performance could only reach 47% of the fresh catalyst.

[0105] The results of the time required for the removal effect of ethanol, acetaldehyde and diethyl sulfide of the regenerated catalyst to reach 100% and the regeneration performance of the regenerated catalyst relative to the fresh catalyst in each embodiment and comparative example are shown in Table 1.

[0106] Table 1

[0107]

[0108]

[0109] In addition, according to the specific test results, the attached drawings respectively provide schematic diagrams showing the changes in the removal rates of ethanol, acetaldehyde and diethyl sulfide of the catalysts described in the embodiments and comparative examples over time, as shown in detail as follows.

[0110] Figure 1 A schematic diagram showing the ethanol removal rate of the catalysts in Examples 1 to 17 and Comparative Examples 1 to 3 is shown;

[0111] Figure 2 A schematic diagram showing the acetaldehyde removal rate of the catalysts in Examples 1 to 17 and Comparative Examples 1 to 3 is shown;

[0112] Figure 3 A schematic diagram of the removal rate of diethyl sulfide by the catalysts in Examples 1 to 17 and Comparative Examples 1 to 3 is shown.

[0113] Examples 1 to 16 are all catalysts obtained by the regeneration method of the present invention. Figure 1 , Figure 2 , Figure 3 It can be seen that the time for the obtained regenerated catalyst to reach 100% removal rate of ethanol, acetaldehyde and diethyl sulfide is significantly extended compared with Comparative Examples 1 to 3. On the other hand, the catalysts described in Examples 1 to 16 can maintain a high removal rate for a long time, and the speed of the corresponding removal rate decrease is also significantly slow; while the removal efficiency of the regenerated catalysts described in Comparative Examples 1 to 3 decreases significantly in a short time, and the rate of decrease is also very fast. In particular, as time goes by, the change in the removal effect of the catalyst obtained within the preferred range proposed by the present invention is very close to that of the fresh catalyst of Example 17, and the best one almost reaches the level of the fresh catalyst.

[0114] In summary, the above-mentioned embodiments of the present invention achieve that the metal oxide active components in the regenerated Mn-based catalyst can be well restored, and the catalytic activity of the obtained catalyst can reach more than 83% of that of the fresh catalyst, and the catalytic activity of the best regenerated catalyst can even reach more than 95% of that of the fresh catalyst, and the regeneration method has low raw material cost and can be recycled and reused, and is easy to operate, and there is no secondary pollution of waste water and waste gas during the regeneration process. In addition, the regenerated sulfur can be recycled and reused, which can generate certain economic added value.

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry, characterized in that: The deactivated Mn-based catalyst is deactivated by the simultaneous influence of carbon and sulfur, and the surface is covered with sulfur-containing substances and carbonates, wherein the sulfur-containing substances include elemental sulfur and sulfides, and the active component manganese oxide is partially deactivated to form manganese sulfate and manganese sulfide. The method comprises the following steps: Step (1), mixing and stirring the deactivated Mn-based catalyst and a desulfurization solvent A to form a mixed slurry B; the desulfurization solvent A comprises a first solvent, which is one or more of methanol, ethanol, propanol and ethylene glycol; the desulfurization solvent A also comprises a second solvent, which is carbon disulfide and / or DMF, and the mass ratio of the first solvent to the second solvent is (1-10):1; the mass ratio of the deactivated Mn-based catalyst to the desulfurization solvent A in step (1) is 1:(3-8); Step (2), filtering the mixed slurry B to obtain a solid C and a washing liquid D; Step (3), subjecting the solid C and potassium permanganate to an oxidation reaction in deionized water to obtain a solid E; wherein the mass ratio of the solid C, the potassium permanganate and the deionized water is 1:(0.05-0.2):(3-8); Step (4), calcining the solid E in an oxygen-containing atmosphere to obtain a regenerated Mn-based catalyst.

2. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 1, characterized in that: The first solvent is a mixture of methanol and ethanol.

3. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 1, characterized in that: The desulfurization solvent A is a mixture of ethanol and carbon disulfide in a mass ratio of (1-3):1, or a mixture of ethanol and DMF in a mass ratio of (5-8):

1.

4. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 1, characterized in that: The mixed deactivated Mn-based catalyst and the desulfurization solvent A are stirred under ultrasonic conditions.

5. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 4, characterized in that: The ultrasonic stirring time is 10~30min, and the ultrasonic stirring temperature is 25~45℃.

6. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to any one of claims 1 to 3, characterized in that: After filtering the mixed slurry B, the step (2) further comprises the step of washing the solid C with anhydrous ethanol.

7. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 6, characterized in that: The mass of the anhydrous ethanol used in the cleaning is 3 to 5 times the mass of the deactivated Mn-based catalyst.

8. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 1, characterized in that: The oxidation reaction time is 0.5 to 1.5 hours.

9. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 1, characterized in that: After the oxidation reaction is completed, the step (3) further comprises: filtering and drying the product after the oxidation reaction in sequence to obtain the solid E.

10. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 9, characterized in that: The drying temperature is 85-105° C., and the drying time is 9-15 hours.

11. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to any one of claims 1 to 3, characterized in that: In the step (4), the oxygen-containing atmosphere is an oxygen-containing atmosphere having an oxygen content of 40 to 55 vol%.

12. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 11, characterized in that: In the step (4), the oxygen-containing atmosphere is oxygen-enriched air with an oxygen content of 40-55 vol%, or an oxygen / nitrogen mixed gas with an oxygen content of 40-55 vol%.

13. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 11, characterized in that: The calcination temperature in the calcination process is 400-700° C., and the calcination time is 1-4 hours.

14. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 11, characterized in that: The solid E is placed in a tube furnace for calcination.

15. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 1, characterized in that: The regeneration method further comprises: recovering the washing liquid D by distillation to obtain a recovered solvent, and returning at least a portion of the recovered solvent to the step (1) for recycling as the desulfurization solvent A.

16. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 15, characterized in that: The distillation temperature in the distillation is 160-170°C.

17. The method for regenerating a deactivated Mn-based catalyst for removing VOCs in the fermentation industry according to claim 15, characterized in that: The sulfur liquid remaining after the distillation is collected and cooled to obtain solid elemental sulfur.

18. A regenerated Mn-based catalyst for removing VOCs in the fermentation industry, characterized in that: It is prepared by the regeneration method described in any one of claims 1 to 17, and the catalytic activity of the regenerated Mn-based catalyst in purifying VOCs during fermentation is more than 83% of the catalytic activity of the fresh Mn-based catalyst.

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