Clay catalyst regeneration system

Abstract

The utility model provides a regeneration system of a clay catalyst. The regeneration system comprises a first reactor, a second reactor and a calcining device, the inner space of the first reactor is used for loading a clay catalyst, the first reactor comprises a first inlet, a first outlet, a second outlet and a fourth inlet, and the fourth inlet is used for introducing inert gas; the second reactor comprises a second inlet and a third outlet; the calcining device comprises a third inlet and is used for oxygenolysis of the clay catalyst; the first outlet is communicated with the second inlet through a first pipeline and is used for outputting waste liquid generated after the clay catalyst is separated; the second reactor is used for depolymerizing the polymer in the waste liquid and generating a monomer; the first inlet is used for introducing a monomer into the first reactor; the second outlet is communicated with the third inlet through a third pipeline and is used for discharging the separated clay catalyst; the third outlet is communicated with the first inlet through a second pipeline. By means of the regeneration system, efficient regeneration of the clay catalyst is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of catalyst recovery and regeneration, particularly relates to a regeneration system of clay catalyst. BACKGROUND

[0002] Clay minerals are a kind of hydrous silicate minerals with layered structure, the main components are SiO2, Al2O3 and water, typical representatives include kaolin, montmorillonite and bentonite etc. Its unique layered structure endows it with interlayer ion exchange, interlayer adsorption, interlayer expansion, thixotropic bonding and other characteristics, and the clay catalyst treated by acid modification has the advantages of high conversion rate, long service life and neutral product characteristics in the ring-opening polymerization and copolymerization of tetrahydrofuran (THF), ethylene oxide and other cyclic ether compounds.

[0003] In such catalytic polymerization reaction process, metal ions, organic impurities and heavy components carried by raw materials will be continuously accumulated by impregnation adsorption on the surface of the catalyst. These pollutants not only occupy the acid active sites, but also block the structure channels, resulting in the following deactivation characteristics of the catalyst: (1) product color value deterioration; (2) the proportion of polymerization side reactions (chain transfer, chain exchange) increases; (3) the product viscosity and molecular weight distribution deviate from the control index. When the above deactivation phenomena appear intensively, the catalyst needs to be replaced in batches. However, the catalyst in the high-viscosity polymer system is difficult to unload directly, and needs to be cleaned through multiple cleaning processes to remove the polymer residues in the pores, and then can be disposed of by hazardous waste landfill or regeneration treatment. This process not only produces high-concentration organic wastewater, but also has very high treatment cost.

[0004] The existing clay catalyst regeneration device has many key defects, for example, the device using chemical cleaning method will have the problems of incomplete cleaning, large solvent consumption, high-concentration organic wastewater and serious catalyst wear. Therefore, it is urgent to develop a new system for regenerating clay catalyst deactivated by impurities accumulation, which can realize the recycling of the catalyst without damaging the performance of the clay catalyst, reduce production cost and environmental pollution. UTILITY MODEL CONTENT

[0005] The technical problem to be solved by the utility model is to overcome the key defects of the existing clay catalyst regeneration device, for example, the device using chemical cleaning method will have the defects of incomplete cleaning, large solvent consumption, high-concentration organic wastewater and serious catalyst wear, and provide a regeneration system of clay catalyst.

[0006] The utility model solves the above technical problems through the following technical scheme:

[0007] The utility model provides a regeneration system of clay catalyst, the regeneration system comprises: a first reactor, a second reactor and a calcining device.

[0008] The internal space of the first reactor is used to load the clay catalyst to be regenerated, the first reactor further comprises a first inlet, a first outlet, a second outlet and a fourth inlet, the fourth inlet is used to pass in inert gas; the second reactor comprises a second inlet and a third outlet; the calcining device comprises a third inlet, and the calcining device is used to oxidatively decompose the clay catalyst;

[0009] The first outlet is communicated with the second inlet through a first pipeline, the first outlet is used to transport the waste liquid generated after the clay catalyst is separated in the first reactor into the first pipeline; the second reactor is used to depolymerize the polymer in the waste liquid to obtain a gas phase monomer, and the gas phase monomer is output from the third outlet; and the first inlet is used to pass the gas phase monomer into the first reactor to wash the clay catalyst in the first reactor;

[0010] The second outlet is communicated with the third inlet through a third pipeline, and the second outlet is used to discharge the separated clay catalyst into the third pipeline;

[0011] The third outlet is communicated with the first inlet through a second pipeline.

[0012] In the scheme, the first reactor, the second reactor and the calcining device work cooperatively, the method of inert gas assisted purging and gas phase monomer circulating washing is used to replace the traditional chemical cleaning method, the efficient regeneration of the clay catalyst is realized, the waste liquid and the clay catalyst are preliminarily separated in the first reactor, the waste liquid is depolymerized into a gas phase monomer in the second reactor, and then the gas phase monomer is circulated back to the first reactor and used for washing, the pollution of chemical solvents and the abrasion of the catalyst are avoided, and finally the residual impurities are completely oxidatively decomposed through the calcining device, so that the problems of incomplete cleaning of the traditional device, large solvent consumption, serious wastewater pollution and mechanical damage of the catalyst are solved, and the scheme has the significant advantages of high regeneration efficiency, environmental protection and energy saving and low catalyst loss.

[0013] Optionally, the first reactor further comprises a fourth outlet, the first inlet and the fourth inlet are located at the upper part of the first reactor, the first outlet and the second outlet are located at the bottom of the first reactor, and the fourth outlet is located at the top of the first reactor, and the fourth outlet is used to discharge the inert gas carrying the gas phase monomer.

[0014] In the scheme, the fourth outlet is arranged at the top, the inert gas carrying the gas phase monomer can be discharged from the first reactor in time, the accumulation of the inert gas in the reactor is effectively prevented to cause the pressure to rise, and the internal pressure of the reactor is stable and the airflow is smooth.

[0015] Optionally, the first reactor further comprises a fifth inlet, the fifth inlet is arranged at the lower part of the first reactor, and the fifth inlet is used for introducing inert gas.

[0016] Optionally, the regeneration system further comprises a monomer collecting device, the monomer collecting device comprises a condenser, an inlet of the condenser is communicated with the fourth outlet, and the condenser is used for condensing the inert gas carrying the gas-phase monomer.

[0017] In the scheme, by additionally arranging the monomer collecting device with the condenser and communicating the fourth outlet with the inlet of the condenser, the inert gas carrying the gas-phase monomer discharged from the first reactor can be effectively condensed to liquefy the gas-phase monomer for recycling, so that the monomer recycling is realized, the environmental pollution and resource waste caused by direct monomer discharge are avoided, and the content of the monomer entrained in the inert gas is reduced.

[0018] Optionally, the monomer collecting device further comprises a first collecting tank, an inlet of the first collecting tank is communicated with an outlet of the condenser, and the first collecting tank is used for collecting the monomer condensate output from the condenser.

[0019] In the scheme, by additionally arranging the first collecting tank communicated with the outlet of the condenser, the monomer condensate output from the condenser can be collected in the first collecting tank, so that the stable storage and subsequent recycling of the monomer condensate are realized.

[0020] Optionally, a gas discharge port is further arranged on the first collecting tank, and the gas discharge port is used for discharging the inert gas.

[0021] In the scheme, by arranging the gas discharge port on the first collecting tank, the remaining inert gas after condensation can be discharged in time, the abnormal pressure rise in the tank is prevented, the stable pressure in the first collecting tank is ensured, and the safe storage and normal collection of the monomer condensate are ensured.

[0022] Optionally, the regeneration system further comprises a monomer purification and recycling device, the monomer purification and recycling device comprises a sixth inlet, the sixth inlet is communicated with a liquid outlet of the first collecting tank through a fourth pipeline, and the monomer purification and recycling device is used for purifying the recycled monomer condensate.

[0023] In the scheme, by additionally arranging the monomer purification and recycling device communicated with the liquid outlet of the collecting tank, the recycled monomer condensate can be further purified to remove impurities and unreacted components, so that the purity and quality of the monomer are significantly improved.

[0024] Optionally, the monomer purification and recycling device further comprises a seventh inlet, and the seventh inlet is communicated with the third outlet through a fifth pipeline.

[0025] Optionally, the regeneration system further comprises a first delivery pump arranged on the first pipeline, and the first delivery pump is configured to pressurize the waste liquid in the first pipeline to enable the waste liquid to enter the second reactor.

[0026] The fourth pipeline is further provided with a second delivery pump configured to pressurize the monomer condensate in the fourth pipeline to enable the monomer condensate to enter the monomer purification and recovery device.

[0027] In the scheme, the first delivery pump is arranged on the pipeline to effectively pressurize and deliver the waste liquid, thereby ensuring that the waste liquid can smoothly enter the second reactor from the first reactor through the first pipeline for depolymerization treatment, effectively improving the material transmission efficiency and the continuity of system operation, avoiding the problem of poor delivery caused by insufficient fluid pressure, and enhancing the reliability and stability of the entire regeneration system operation.

[0028] The second delivery pump is arranged on the pipeline to effectively pressurize and deliver the monomer condensate, thereby ensuring that the monomer condensate can be stably delivered from the first collection tank to the monomer purification and recovery device through the fourth pipeline for purification, improving the material transmission efficiency and the continuity of system operation, avoiding the problem of poor delivery caused by insufficient fluid pressure, and enhancing the reliability and stability of the entire regeneration system operation.

[0029] Optionally, the regeneration system further comprises a second collection tank arranged on the first pipeline, and the second collection tank is configured to collect the waste liquid.

[0030] In the scheme, the second collection tank is arranged on the first pipeline to temporarily store and collect the waste liquid discharged from the first reactor, thereby providing a stable buffer and adjustment function for subsequent delivery of the waste liquid to the second reactor for depolymerization treatment, ensuring that the waste liquid enters the subsequent treatment link at a controllable flow rate and pressure, and avoiding the influence of flow fluctuation on the stable operation of the second reactor.

[0031] The positive progress effect of the utility model lies in:

[0032] The first reactor, the second reactor and the calcining device are arranged to work cooperatively, inert gas assisted purging and gas phase monomer circulating washing are used to replace the traditional chemical cleaning method, efficient regeneration of clay catalyst is realized, the waste liquid is preliminarily separated from the clay catalyst in the first reactor, the waste liquid is recycled to the first reactor after being depolymerized into gas phase monomer in the second reactor and is used for washing, chemical solvent pollution and catalyst abrasion are avoided, and finally the calcining device is used to completely oxidize and decompose residual impurities, thereby solving the problems of incomplete cleaning of the traditional device, large solvent consumption, serious wastewater pollution and mechanical damage of the catalyst, and the scheme has the remarkable advantages of high regeneration efficiency, environmental protection and energy saving and low catalyst loss. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A structure schematic view of a regeneration system of a clay catalyst provided by an embodiment of the present application.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] First reactor 1

[0036] First inlet 101

[0037] First outlet 102

[0038] Second outlet 103

[0039] Fourth inlet 104

[0040] Fourth outlet 105

[0041] Fifth inlet 106

[0042] Second reactor 2

[0043] Second inlet 201

[0044] Third outlet 202

[0045] Liquid level controller 203

[0046] Calcining device 3

[0047] Third inlet 301

[0048] Fifth outlet 302

[0049] Eighth inlet 303

[0050] Condenser 4

[0051] Monomer purification and recovery device 5

[0052] Sixth inlet 501

[0053] Seventh inlet 502

[0054] First pipeline 6

[0055] Second pipeline 7

[0056] Third pipeline 8

[0057] Fourth pipeline 9

[0058] Fifth pipeline 10

[0059] First valve 11

[0060] Second valve 12

[0061] Third valve 13

[0062] first delivery pump 14

[0063] second delivery pump 15

[0064] first collection tank 16

[0065] gas discharge port 161

[0066] second collection tank 17 DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0068] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain specific posture, and if the specific posture changes, the directional indications also change accordingly.

[0069] In addition, if the embodiments of the present application involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skill in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0070] Embodiment 1

[0071] The embodiment of the present application provides a regeneration system of clay catalyst, Figure 1The utility model provides a kind of regeneration system of clay catalyst for the structure schematic diagram of an embodiment of the utility model, the regeneration system includes: first reactor 1, second reactor 2 and calcining device 3;The internal space of first reactor 1 is used to load the clay catalyst to be regenerated, first reactor 1 further includes first inlet 101, first outlet 102, second outlet 103 and fourth inlet 104, and fourth inlet 104 is used to pass into inert gas;Second reactor 2 includes second inlet 201 and third outlet 202;Calcining device 3 includes third inlet 301, and calcining device 3 is used to carry out oxidation decomposition to clay catalyst;First outlet 102 is communicated with second inlet 201 by first pipeline 6, and first outlet 102 is used to transport the waste liquid generated after separating clay catalyst in first reactor 1 into first pipeline 6;Second reactor 2 is used to depolymerize polymer in waste liquid to obtain gas phase monomer, and is output by third outlet 202;First inlet 101 is used to pass into gas phase monomer in first reactor 1 to wash clay catalyst in first reactor 1;Second outlet 103 is communicated with third inlet 301 by third pipeline 8, and second outlet 103 is used to discharge separated clay catalyst into third pipeline 8;Third outlet 202 is communicated with first inlet 101 by second pipeline 7.

[0072] By setting first reactor 1, second reactor 2 and calcining device 3 work cooperatively, the method of inert gas auxiliary purging and gas phase monomer circulation washing is used to replace traditional chemical cleaning method, the efficient regeneration of clay catalyst is realized, first, waste liquid and clay catalyst are preliminarily separated in first reactor 1, waste liquid is depolymerized into gas phase monomer in second reactor 2 and then recycled to first reactor 1 and is used for washing, chemical solvent pollution and catalyst abrasion are avoided, finally, residual impurities are completely oxidized and decomposed by calcining device 3, so that the problems of incomplete cleaning of traditional device, large solvent consumption, serious wastewater pollution and catalyst mechanical damage are solved, and the regeneration system has the significant advantages of high regeneration efficiency, environmental protection and energy saving and low catalyst loss.

[0073] In the embodiment of the application, first reactor 1 further includes fourth outlet 105, first inlet 101 and fourth inlet 104 are located at the upper part of first reactor 1, first outlet 102 and second outlet 103 are located at the bottom of first reactor 1, and fourth outlet 105 is located at the top of first reactor 1, and fourth outlet 105 is used to discharge inert gas carrying gas phase monomer. Among them, the inert gas is nitrogen.

[0074] By setting fourth outlet 105 at the top, inert gas carrying gas phase monomer can be discharged from first reactor 1 in time, effectively preventing pressure rise caused by inert gas accumulation in the reactor, and ensuring stable internal pressure and smooth airflow of the reactor.

[0075] Further, the first reactor 1 further comprises a fifth inlet 106, which is arranged at the lower part of the first reactor 1 and is used for introducing inert gas.

[0076] In this embodiment, the regeneration system further comprises a monomer collecting device, which comprises a condenser 4, an inlet of the condenser 4 being communicated with the fourth outlet 105, and the condenser 4 is used for condensing the inert gas carrying the gaseous monomer.

[0077] By additionally arranging the monomer collecting device with the condenser 4 and communicating the fourth outlet 105 with the inlet of the condenser 4, the inert gas carrying the gaseous monomer discharged from the first reactor 1 can be effectively condensed, so that the gaseous monomer is liquefied and recovered, not only realizing the recycling of the monomer, but also avoiding the environmental pollution and resource waste caused by direct discharge of the monomer, and reducing the content of the monomer entrained in the inert gas.

[0078] Specifically, the inert gas carrying the gaseous monomer is output from the fourth outlet 105 of the first reactor 1, input into the condenser 4, condensed through the condenser 4, and the monomer is changed from gaseous phase to liquid phase, so that the monomer and the inert gas are separated.

[0079] The collecting device further comprises a first collecting tank 16, an inlet of the first collecting tank 16 being communicated with an outlet of the condenser 4, and the first collecting tank 16 is used for collecting the monomer condensate output from the condenser 4. A gas discharge port 161 is further arranged on the first collecting tank 16, and the gas discharge port 161 is used for discharging the inert gas.

[0080] By additionally arranging the first collecting tank 16 communicated with the outlet of the condenser 4, the monomer condensate output from the condenser 4 can be collected in the first collecting tank 16, so that the stable storage and subsequent recycling of the monomer condensate are realized. By arranging the gas discharge port 161 on the first collecting tank 16, the remaining inert gas after condensation can be discharged in time, so that the abnormal increase of the pressure in the tank is prevented, the stable pressure in the first collecting tank 16 is ensured, and the safe storage and normal collection of the monomer condensate are ensured.

[0081] In this embodiment, the regeneration system further comprises a monomer purification and recovery device 5, which comprises a sixth inlet 501 communicated with a liquid outlet of the first collecting tank 16 through a fourth pipeline 9, and the monomer purification and recovery device 5 is used for purifying the recovered monomer condensate.

[0082] By additionally arranging the monomer purification and recovery device 5 communicated with the liquid outlet of the collecting tank, the recovered monomer condensate can be further purified and treated to remove the impurities and unreacted components, so that the purity and quality of the monomer are significantly improved.

[0083] Specifically, the monomer purification and recovery device 5 further comprises a seventh inlet 502, and the seventh inlet 502 is communicated with the third outlet 202 through the fifth pipeline 10. A part of the gas-phase monomer produced by the depolymerization in the second reactor 2 is transported into the first reactor 1 through the second pipeline 7 to wash the clay catalyst in the first reactor 1, and another part is directly transported into the monomer purification and recovery device 5 for purification and recovery.

[0084] In the embodiment, the regeneration system further comprises a first delivery pump 14 arranged on the first pipeline 6, and the first delivery pump 14 is used to pressurize the waste liquid in the first pipeline 6 to make the waste liquid enter the second reactor 2. The fourth pipeline 9 is further provided with a second delivery pump 15, and the second delivery pump 15 is used to pressurize the monomer condensate in the fourth pipeline 9 to make the monomer condensate enter the monomer purification and recovery device 5.

[0085] By arranging the first delivery pump 14 and the second delivery pump 15 on the key pipelines, the waste liquid and the monomer condensate are effectively pressurized and delivered, respectively, so as to ensure that the waste liquid can smoothly enter the second reactor 2 from the first reactor 1 through the first pipeline 6 for depolymerization treatment, and the monomer condensate can stably enter the monomer purification and recovery device 5 from the first collection tank 16 through the fourth pipeline 9 for purification. This not only improves the material transmission efficiency of each process link and the continuity of system operation, but also avoids the problems of poor delivery caused by insufficient fluid pressure, thereby enhancing the reliability and stability of the operation of the entire regeneration system.

[0086] Optionally, the regeneration system further comprises a second collection tank 17 arranged on the first pipeline 6, and the second collection tank 17 is used to collect the waste liquid.

[0087] By arranging the second collection tank 17 on the first pipeline 6, the waste liquid discharged from the first reactor 1 can be temporarily stored and collected, thereby providing a stable buffering and adjusting function for subsequent delivery of the waste liquid to the second reactor 2 for depolymerization treatment, so as to ensure that the waste liquid enters the subsequent treatment link at a controllable flow rate and pressure, and avoid affecting the stable operation of the second reactor 2 due to flow fluctuation.

[0088] The use method of the regeneration system of the clay catalyst will be specifically described below in combination with Figure 1

[0089] ​The clay catalyst to be treated is loaded into the first reactor 1 through the special loading port of the first reactor 1. The first reactor 1 is provided with a first inlet 101 on the right side wall of the upper part, a fourth inlet 104 on the left side wall of the upper part, a fifth inlet 106 on the left side wall of the lower part, a fourth outlet 105 on the top, and a first outlet 102 and a second outlet 103 on the bottom. The fourth inlet 104 and the fifth inlet 106 are used to introduce inert gas nitrogen to purge the surface of the clay catalyst in the first reactor 1, so as to pressurize and separate the residual reaction liquid (which contains unreacted monomers and / or organic impurities) on the surface of the clay catalyst. The waste liquid (containing monomers) generated after pressurization and separation is discharged from the first outlet 102, collected by the second collection tank 17 provided on the first pipeline 6, and communicated with the inlet of the second reactor 2. The second collection tank 17 is also provided with a first delivery pump 14 between the second collection tank 17 and the second reactor 2. The waste liquid collected by the second collection tank 17 is pressurized by the first delivery pump 14 and delivered to the second reactor 2 through the first pipeline 6. The second reactor 2 depolymerizes the polymer in the waste liquid to obtain gas-phase monomers, which are output through the third outlet 202. The gas-phase monomers are then input into the first reactor 1 through the second pipeline 7 to wash the clay catalyst. The above-mentioned circulation loop is used to wash the clay catalyst in the first reactor 1 multiple times. The second pipeline 7 is also provided with a first valve 11 for controlling the opening or closing of the second pipeline 7. During the circulation and washing of the clay catalyst, the first valve 11 is in an open state. After the washing is completed, the first valve 11 is closed.

[0090] After the washing of the clay catalyst is completed, the clay catalyst is unloaded from the second outlet 103 of the first reactor 1 and delivered to the calcining device 3. The calcining device 3 is a rotary kiln. The calcining device 3 includes an eighth inlet 303 and a fifth outlet 302. The eighth inlet 303 is used to introduce a gas containing N2O. The calcining device 3 is used to oxidize and decompose the clay catalyst. The final product is discharged from the fifth outlet 302 of the calcining device 3, realizing the regeneration of the clay catalyst.

[0091] After the washing of the clay catalyst is completed, the fourth outlet 105 of the first reactor 1 discharges the inert gas carrying the gas phase monomer, the fourth outlet 105 is communicated with the inlet of the condenser 4, and a second valve 12 is further arranged between the first reactor 1 and the condenser 4, the second valve 12 is closed during the process of the circulating washing of the clay catalyst, and the second valve 12 is opened after the washing is completed. The inert gas carrying the gas phase monomer is condensed by the condenser 4 to obtain monomer condensate, and the monomer condensate and the inert gas are discharged through the outlet of the condenser 4 into the first collecting tank 16, the first collecting tank 16 is provided with a gas discharge port 161, and the inert gas is discharged from the gas discharge port 161. The subsequent monomer condensate is transported to the monomer purification and recovery device 5 through the fourth pipeline 9, and the monomer purification and recovery device 5 is used for purifying the recovered monomer condensate. A second delivery pump 15 is further arranged between the first collecting tank 16 and the monomer purification and recovery device 5, and is used for pressurizing the monomer condensate.

[0092] The monomer purification and recovery device 5 further comprises a seventh inlet 502, the seventh inlet 502 is communicated with the third outlet 202 through a fifth pipeline 10, the fifth pipeline 10 is further provided with a third valve 13, the second reactor 2 is further provided with a liquid level controller 203, the liquid level controller 203 is electrically connected with the third valve 13, and is used for controlling the opening or closing of the third valve 13 based on the liquid level in the second reactor 2. If the liquid level in the second reactor 2 exceeds the preset value during the process of the circulating washing of the clay catalyst, the third valve 13 is opened, and the excess monomer in the second reactor 2 is directly transported to the monomer purification and recovery device 5 through the fifth pipeline 10 for purification and recovery.

[0093] The effect data of the product treated based on the above-mentioned regeneration system of the clay catalyst will be shown in the following regeneration method of the clay catalyst:

[0094] In this embodiment, the waste catalyst of a polytetrahydrofuran device of a certain enterprise in Xinjiang is used, the clay catalyst K-306 of Clariant is used, the main raw material is sodium-based montmorillonite, and the device has been continuously operated for 7 years and needs to be scrapped. The catalyst loading capacity of the reactor is 50 tons.

[0095] Step 1, in the first reactor, the residual reaction liquid (including polytetrahydrofuran (PTMEG), unreacted tetrahydrofuran (THF) monomer and other trace organic impurities) remaining on the surface of the catalyst to be recovered is blown to the second collecting tank by using nitrogen.

[0096] Among them, the main components of the residual reaction liquid are PTMEG and THF, and the specific contents are as shown in the following table 1:

[0097] Table 1

[0098]

[0099] Step 2, the residual reaction solution is transported to the second reactor by the first transport pump, and depolymerization occurs under the catalysis of brand new clay catalyst (Claysoil clay catalyst K-306, main raw material sodium-based montmorillonite) (the pressure is maintained at 0.8 MPa, and the temperature is controlled at 160±5°C) to generate THF monomer and a small amount of water to form a gaseous mixture.

[0100] Step 3, the gaseous mixture of THF monomer and water formed in step 2 is introduced into the first reactor in a gaseous phase from the top of the second reactor to contact with the catalyst to be recovered, and the gas phase condenses to release heat, so that the temperature of the first reactor is maintained at 160±5°C, and the pressure is 0.75 MPa.

[0101] Under this condition, the residual polymer immersed in the channel in step 1 which is not completely blown off is decomposed into THF monomer and water by using the acid sites of the catalyst to be recovered; in this process, the newly generated THF monomer and water can also play a washing role to dissolve and remove the accumulated substances on the surface and in the channel of the catalyst to be recovered.

[0102] The mixture in the first reactor enters the second collection tank from top to bottom, and then is transported into the second reactor by the first transport pump to generate a gaseous mixture of THF and water, part of which continues to circulate back to the first reactor, and part of which is transported to a monomer purification and recovery device under the liquid level control of the second reactor. Through continuous decomposition and washing, the surface of the catalyst to be recovered is cleaned and the fluidity is restored.

[0103] During this period, the fluidity of the catalyst to be recovered is judged according to the size of the angle of repose, and when the angle of repose is ≤45°, it is considered that the fluidity of the catalyst has been restored. If it has been restored, step 4 is performed; if it has not been completely restored, the process cycle is continued in step 2.

[0104] Step 4, when the surface of the catalyst is cleaned and the fluidity is restored, the residual THF and water are removed by stripping, hot nitrogen gas at 165°C is introduced into the first reactor, and the system pressure is maintained at 0.15 MPa. After the gaseous components discharged are condensed, the THF monomer is transported to a monomer purification and recovery device, and the hot nitrogen is discharged. When the THF content in the hot nitrogen gas in the first reactor is less than 500 ppm, the nitrogen supply is terminated, and the catalyst to be recovered is unloaded.

[0105] Step 5, the catalyst to be recovered is transported to a rotary kiln, and a pure N2O is used as a regeneration gas to perform a redox treatment at a low temperature of 300°C for 3 h, and the total volume space velocity is 1000 h -1 The regenerated catalyst is unloaded into a barrel for standby, and the catalyst regeneration process is completed.

[0106] Example 2

[0107] This example is based on Example 1, only the pressure of depolymerization reaction in step 2 is adjusted to 2.0 MPa, the reaction temperature is 180℃, and other operations are the same as Example 1.

[0108] Example 3

[0109] This example is based on Example 1, only the depolymerization reaction temperature in step 2 is adjusted to 120℃, and other operations are the same as Example 1.

[0110] Comparative Example 1

[0111] The brand new commercially available catalyst (Clariant K-306, main raw material montmorillonite) has not been subjected to catalytic reaction.

[0112] Comparative Example 2 (high-temperature calcination regeneration method)

[0113] This comparative example is based on Example 1, only the deactivated catalyst in step 5 is treated by high-temperature calcination method, specifically: the catalyst to be recovered is transported to a rotary kiln and air is introduced, heated at 750℃ for 3h, and other operations are the same as Example 1.

[0114] Effect Example 1 Catalyst Pore Distribution

[0115] The pore size distribution is analyzed by mercury intrusion method, specifically using the method of ASTM D4284-07, using Autopore II9220 type mercury porosimeter for measurement, and the results are shown in Table 2 below.

[0116] Table 2

[0117]

[0118] The test results show that the regenerated catalyst of Example 1 shows uniform pore distribution, with pore size mainly concentrated in the range of 10-100 nm, and the pore volume and pore size distribution characteristics are highly consistent with the fresh catalyst (Comparative Example 1). The pore volume of Comparative Example 2 (high-temperature calcined catalyst) is significantly reduced, and the proportion of 10-100 nm pore size is significantly reduced, which is inferred to be due to the destruction of the ordered microstructure of the catalyst during high-temperature calcination, resulting in pore collapse and deterioration of the wide pore size distribution.

[0119] Effect Example 2 Adsorption Performance Test

[0120] The regenerated catalysts obtained by treating Examples 1-3 and Comparative Examples 1-2 are used for adsorption performance test of ammonia nitrogen removal rate.

[0121] The test method is as follows: 100 mL of ammonia-nitrogen wastewater is weighed into a 250 mL conical flask, and 10 g of regenerated catalyst is weighed into the conical flask, and is placed in a 25°C constant temperature water bath shaking box at a rotation speed of 100 rpm for 1 hour. The ammonia-nitrogen concentration of the solution is measured by the Nash reagent colorimetric method (GB7479.87). The adsorption rate V (%) is used to represent the adsorption capacity of the regenerated catalyst, v=(C o -C) / C o *100, C0 refers to the initial concentration of ammonia-nitrogen wastewater, C0 is 100 mg / L.

[0122] The test results are shown in Table 3 below.

[0123] Table 3

[0124]

[0125] The test results show that the catalysts of Examples 1-3 all exhibit excellent ammonia-nitrogen adsorption performance, and the adsorption capacity even exceeds that of Comparative Example 1 (fresh catalyst). This shows that the regeneration process effectively protects the crystal structure of the catalyst while optimizing the pore structure thereof, thereby improving the adsorption efficiency. In sharp contrast, the adsorption performance of Comparative Example 2 (high-temperature calcined catalyst) is significantly lower than that of Examples 1-3, which further proves that high-temperature calcination can remove organic matter in the pores, but will irreversibly damage the porous structure of the catalyst.

[0126] Effect Example 3 Depolymerization Reaction Test

[0127] The regenerated catalysts obtained by treating Examples 1-3 and Comparative Examples 1-2 are used for depolymerization reaction tests.

[0128] The test method is as follows:

[0129] 1. Reaction Step

[0130] In a 500 mL reaction kettle, 300 g of commercially available polytetrahydrofuran (molecular weight ~1800) and 60 g of catalyst are added, the reaction kettle is tightly closed, airtight test is performed, and the reaction kettle is replaced with nitrogen three times. The reaction conditions are set as follows: temperature 130°C, normal pressure, stirring rate 1000 r / min, and reaction time 1 hour. After the reaction is completed, the reaction system is cooled to room temperature. Sampling is performed for subsequent analysis.

[0131] Note: The entire reaction process must ensure that the system is sealed and leak-free.

[0132] 2. Depolymerization Rate Determination

[0133] The content of the polymer was separated using a rotary evaporator (BUCHI, R-490) with the following operating steps: about 100 g of the above cooled reaction liquid sample was weighed into a 500 mL rotary evaporating flask with a known mass, and was kept in an oil bath at 160°C under normal pressure for 30 min. Then the vacuum pump was turned on, and the distillation was continued at 10 mbar for 1 hour. After cooling to room temperature, the rotary evaporating flask was removed, and the oil bath medium residue on the outside of the flask was carefully wiped with filter paper. The total mass of the rotary evaporating flask and the residue therein was weighed, and the depolymerization rate was calculated according to the following formula: Depolymerization rate (wt%) = (A / E)*100%.

[0134] wherein:

[0135] A: mass of the residue after rotary evaporation (g)

[0136] E: initial mass of the sample weighed (g)

[0137] 3. Distillate component analysis

[0138] The organic matter distilled by rotary evaporation was collected and analyzed using a gas chromatograph (Thermo Fisher Trace1310), and the content of each component was quantitatively analyzed by area normalization method.

[0139] The test results are shown in Table 4 below.

[0140] Table 4

[0141]

[0142] The test results show that Examples 1-3 all show high depolymerization rates, indicating that the regenerated catalysts maintain good activity in the polymer depolymerization reaction, and their performance is close to that of Comparative Example 1 (fresh catalyst), which is consistent with the aforementioned pore distribution results. In contrast, the depolymerization performance of Comparative Example 2 (high-temperature calcined catalyst) is significantly decreased, which is much lower than that of Examples 1-3 and Comparative Example 1, indicating that the high-temperature calcination process damages the catalyst activity.

[0143] Effect Example 4 Polymerization reaction test

[0144] The regenerated catalyst obtained by Example 1 and the brand new catalyst in Comparative Example 1 were respectively subjected to THF polymerization reaction test. The test method was as follows:

[0145] (1) Conversion rate

[0146] Take catalyst 21.6 g, THF monomer 80 g, acetic anhydride 3.5 g, and place it in the reaction kettle. Tighten the cover plate of the reaction kettle to ensure a good seal. Replace with nitrogen, repeat the pressure rise and fall 3 times, and then keep the pressure of the reaction kettle at 3 MPa. Place the reaction kettle in a 36°C constant temperature water bath, stir at 300 rpm, and continue to react for 24 h. After the reaction is completed, use a centrifuge to separate the catalyst from the reaction liquid. Take the supernatant to an oil bath at 95°C for rotary evaporation, and measure the conversion rate.

[0147] wherein the polymer conversion rate = the mass of polymer in the reaction liquid / the total amount of raw materials x 100%.

[0148] The mass of the polymer is the weight of the polymer obtained after rotary evaporation at -80 kPa G, 130°C. The rotary evaporator is a Buchi Rotavapor R215, and the vacuum pump is a VACUUBRAND GMBH + CO KG MD 1C + AK + EK.

[0149] (2) Unreacted acetic anhydride

[0150] Use a potential titrator (Methrom 794 with a 20 ml exchange unit) and follow the following steps: accurately weigh 10.000 g of sample into a 250 mL conical flask, add 50.0 mL of isopropyl alcohol, mix thoroughly until the sample is completely dissolved. Titrate with 0.1000 M KOH / isopropyl alcohol solution until the solution changes from colorless to stable red. The titration method is as follows: blank group: only 1 mL is added before titration; sample group: three times of indicator is added: 1.0 mL before titration, 1.0 mL when about 2 / 3 of the titration is completed, and 0.5 mL near the end point.

[0151] The following formula is used to calculate:

[0152] 1) Acid value

[0153]

[0154] wherein,

[0155] P: the volume of potassium hydroxide solution consumed by the sample group mL

[0156] B: the volume of potassium hydroxide solution consumed by the blank group mL

[0157] N: the concentration of potassium hydroxide solution mol / L

[0158] E: the weight of the sample g

[0159] 2) Unreacted acetic anhydride

[0160]

[0161] (3) Colority

[0162] The color number was measured using a Lovibond full-automatic colorimeter PFX195, and the color value was determined according to the platinum-cobalt standard of ASTM D1209.

[0163] (4) Viscosity

[0164] The viscosity (Visco) was measured by the Ubbelohde viscometer method, which was obtained by measuring the time required for a certain volume of liquid to flow through a capillary tube of a certain length and radius. The viscometer tube was clamped in a constant-temperature water bath at 50±0.01℃, and after 20 min, the sample to be measured was sucked into the tube from port A to 2-3 mm above the graduation C. When the liquid flowed through the graduation C, the time t (s) required for the liquid to flow from the graduation C to the graduation E was recorded. Visco (50℃) = time s x K (viscometer constant) x specific gravity.

[0165] (5) Molecular weight

[0166] The molecular weight was determined according to the method ASTM D94-07 (2017), and the number of ester functional groups was obtained by titration; the titrator was an automatic potentiometer T7 of Mettler Toledo.

[0167] (6) Molecular weight distribution index

[0168] The molecular weight distribution index was measured by an Agilent 1260 Infinity II gel chromatograph (GPC), and the mobile phase was THF.

[0169] The test results are shown in Table 5 below.

[0170] Table 5

[0171]

[0172] As can be seen from the above table, the conversion rates and performances of the two are close, and even the conversion rate of the regenerated catalyst of Example 1 is better than that of the fresh catalyst of Comparative Example 1, which shows that the regeneration method of the present application has a significant effect.

[0173] Each of the embodiments in the specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment mainly explains the difference from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the related parts can be referred to the part of the method embodiments.

[0174] The above only describes the preferred embodiments of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A regeneration system of a clay catalyst, characterized by, The regeneration system comprises a first reactor, a second reactor and a calcining device; The first reactor is used for loading clay catalyst to be regenerated, and comprises a first inlet, a first outlet, a second outlet and a fourth inlet for feeding inert gas; the second reactor comprises a second inlet and a third outlet; the calcining device comprises a third inlet and is used for oxidizing and decomposing the clay catalyst; The first outlet is communicated with the second inlet through a first pipeline, and is used for conveying waste liquid generated after separating the clay catalyst in the first reactor into the first pipeline; the second reactor is used for depolymerizing polymer in the waste liquid to obtain gas-phase monomer, which is output through the third outlet; and the first inlet is used for feeding the gas-phase monomer into the first reactor to wash the clay catalyst in the first reactor; The second outlet is communicated with the third inlet through a third pipeline, and is used for discharging the separated clay catalyst into the third pipeline; The third outlet is communicated with the first inlet through a second pipeline.

2. The clay catalyst regeneration system of claim 1, wherein, The first reactor further comprises a fourth outlet, the first inlet and the fourth inlet are located at the upper part of the first reactor, the first outlet and the second outlet are located at the bottom of the first reactor, and the fourth outlet is located at the top of the first reactor and is used for discharging inert gas carrying gas-phase monomer.

3. The clay catalyst regeneration system of claim 2, wherein, The first reactor further comprises a fifth inlet, which is arranged at the lower part of the first reactor and is used for feeding inert gas.

4. A system for the regeneration of clay catalyst according to claim 2 or 3, characterised in that, The regeneration system further comprises a monomer collecting device, which comprises a condenser, the inlet of the condenser is communicated with the fourth outlet, and the condenser is used for condensing inert gas carrying gas-phase monomer.

5. The clay catalyst regeneration system of claim 4, wherein, The collecting device further comprises a first collecting tank, the inlet of the first collecting tank is communicated with the outlet of the condenser, and the first collecting tank is used for collecting monomer condensate output from the condenser.

6. The clay catalyst regeneration system of claim 5, wherein, A gas discharge port is further arranged on the first collecting tank, and is used for discharging inert gas.

7. The clay catalyst regeneration system of claim 6, wherein, The regeneration system further comprises a monomer purification and recovery device, which comprises a sixth inlet, the sixth inlet is communicated with the liquid outlet of the first collecting tank through a fourth pipeline, and the monomer purification and recovery device is used for purifying recovered monomer condensate.

8. The clay catalyst regeneration system of claim 7, wherein, The monomer purification and recovery device further comprises a seventh inlet, which is communicated with the third outlet through a fifth pipeline.

9. The clay catalyst regeneration system of claim 7, wherein, The regeneration system further comprises a first conveying pump arranged on the first pipeline, which is used for pressurizing waste liquid in the first pipeline to make the waste liquid enter the second reactor; A second conveying pump is further arranged on the fourth pipeline, which is used for pressurizing monomer condensate in the fourth pipeline to make the monomer condensate enter the monomer purification and recovery device.

10. The clay catalyst regeneration system of claim 1, wherein, The regeneration system further comprises a second collection tank disposed on the first conduit, the second collection tank for collecting the waste liquid.

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