Preparation method and application of monolithic catalyst filler

Abstract

The invention aims to provide a preparation method and application of a monolithic catalyst filler, and belongs to the technical field of catalyst filler preparation.The monolithic catalyst filler takes a foamed ceramic material as a catalyst carrier, the foamed ceramic material is washed and dried and then is excessively soaked in a Co (NO3) 2.6 H2O and Ce (NO3) 3.6 H2O mixed precursor solution, and the monolithic catalyst filler is obtained. And calcining to obtain the monolithic catalyst, and using the monolithic catalyst as a functional filler for a supergravity rotating packed bed. According to the invention, the integral annular filler is filled in the rotor of the rotating packed bed, and fluid can flow along a relatively regular route, so that the transfer and reaction processes are completed. The rotary packed bed has the advantages of being small in pressure drop, small in liquid holdup, large in production capacity, relatively high in separation efficiency and the like, is convenient to disassemble, can provide a larger interphase contact area, has better mass transfer performance and dynamic balance performance, and can greatly improve the micromixing performance of the rotary packed bed and strengthen the gas-liquid mass transfer process.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst packing preparation, and particularly relates to a preparation method and application of a monolithic catalyst packing. Background Art

[0002] At present, the packings of the commonly used high-gravity rotating packed bed are mostly bulk packings. When installed, the uniformity and symmetry of the packings in the rotor cannot be guaranteed to be unified. And during the high-speed rotation of the rotor, due to the action of centrifugal force, the packings are prone to accumulate along the radial direction at the outer edge of the rotor, thus exacerbating the non-uniformity and asymmetry of the packings, causing abnormal swinging of the rotating packed bed, and reducing the mass transfer efficiency and service life of the whole bed. In addition, the bulk packings placed in disorderly accumulation rub against each other during the rotation of the rotor, which will cause the shedding of the active components loaded on their surfaces, further reducing the reaction activity and mass transfer performance. Moreover, the non-uniformity of the packings will also exacerbate the non-uniformity of liquid distribution, resulting in channeling, wall flow, dead zones inside the packings, and flooding phenomenon. At the same time, there are also problems such as difficult replacement and engineering scale-up for bulk packings, so there are certain limitations in actual engineering applications.

[0003] The monolithic packing is assembled neatly by basic geometric units according to certain rules, and the monolithic annular packing is filled in the rotor of the rotating packed bed. Under the action of the monolithic packing, the fluid can flow along a relatively regular route, and then the transfer and reaction processes are completed. Therefore, the monolithic packing has the advantages of small pressure drop, small liquid holdup, large production capacity, relatively high separation efficiency, etc. Moreover, the monolithic packing is convenient to disassemble, can provide a larger interfacial contact area, usually has better mass transfer performance and dynamic balance performance, and the experimental conditions are not much different from the actual working conditions, so it has a better application prospect in industry.

[0004] The monolithic packings are generally divided into two categories. One is the regular wire mesh packing; the other is the modified foam material packing, mainly including foam metal and foam ceramic packings. Among them, the wire mesh used as the packing of the rotating packed bed is prone to cause the problem of "sparse outside and dense inside" during operation; the foam metal has good mechanical strength, but its surface is relatively smooth and it is not easy to load active substances. The foam ceramic material contains a large number of open and closed pores inside, with a high porosity and uniform distribution. At the same time, it has a small density, a high specific surface area, good permeability to various gases and liquids, and a stable structure. It can be used as a catalyst carrier and is widely used in many aspects such as sound absorption and earthquake resistance, molten metal filtration, catalyst carrier, heat preservation and flame retardancy.

[0005] At present, there have been many reports on the preparation of monolithic catalysts in China. However, there is no report on the preparation of a monolithic catalyst with foam ceramics as the carrier, loading double metals and using it as the packing of a rotating packed bed. The preparation and application of the monolithic catalyst packing will well improve the dynamic balance ability of the rotating packed bed, strengthen gas-liquid mass transfer, and expand the application range of the rotating packed bed. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method and application of a monolithic catalyst packing. The monolithic catalyst packing provided by the present invention is prepared with foam ceramics as the carrier, by loading double metals cobalt and cerium, and is used as a functional packing in a rotating packed bed. This catalyst packing is convenient for replacement and disassembly, and greatly improves gas-liquid mass transfer and enhances the dynamic balance ability of the rotating packed bed.

[0007] The present invention adopts the following technical solutions: A preparation method of a monolithic catalyst packing includes the following steps: S1. Ultrasonic the foam ceramic material in deionized water and wash it clean; S2. Dry the foam ceramic material obtained in S1; S3. Immerse the foam ceramic material obtained in S2 excessively in the mixed precursor solution of Co(NO 3 ) 2 ·6H 2 O and Ce(NO 3 ) 3 ·6H 2 O; S4. Remove the residual liquid in the pores of the foam ceramic obtained in S3 and dry it; S5. Transfer the foam ceramic obtained in S4 into a muffle furnace for calcination, and obtain the monolithic catalyst after cooling.

[0008] Further, the ultrasonic time in S1 is 20 min.

[0009] Further, the drying temperature in S2 is 105 °C and the time is 12 h.

[0010] Further, the molar ratio of Co and Ce in the mixed precursor solution in S3 is 1:1, and the total metal concentration is 0.15 mol / L.

[0011] Further, the drying temperature in S4 is 105 °C and the time is 12 h.

[0012] Further, the calcination temperature in S5 is 550 °C and the time is 3 h.

[0013] An integral catalyst packing is applied to a rotating packing bed for heterogeneous catalytic ozonation degradation of sulfamethoxazole wastewater. The integral catalyst packing is filled in the rotor of the rotating packing bed in the form of an integral annular packing.

[0014] Furthermore, the concentration of the sulfamethoxazole wastewater is 100 mg / L and the volume is 1 L.

[0015] The beneficial effects of the present invention are as follows: The present invention adopts the excess impregnation method, using foam ceramics as the carrier, Co(NO 3 ) 2 ·6H 2 O and Ce(NO 3 ) 3 ·6H 2 O as the mixed precursor solution, and the integral catalyst packing is obtained by impregnation loading and then high-temperature calcination. The prepared integral catalyst packing has good catalytic effect, better enhances gas-liquid mass transfer, is easy to replace, disassemble and install, and enhances the dynamic balance ability of the rotating packing bed.

[0016] 1. The present invention uses foam ceramics as the carrier, Co(NO 3 ) 2 ·6H 2 O and Ce(NO 3 ) 3 ·6H 2 O as the mixed precursor solution, adopts the method of excess impregnation for metal loading, and then conducts high-temperature roasting to prepare the integral catalyst packing, which is filled in the rotor of the rotating packing bed in the form of an integral annular packing.

[0017] 2. The preparation method provided by the present invention has simple process requirements. The integral catalyst packing is prepared by using the excess impregnation loading method, which improves the dynamic balance ability of the rotating packing bed, enhances gas-liquid mass transfer, and is convenient for replacement, disassembly and installation, making up for the defects of bulk packing in the actual engineering application process, and has good industrial application prospects. Description of the Drawings

[0018] Figure 1 It is the top view of the integral catalyst packing of the present invention.

[0019] Figure 2 It is the front view of the integral catalyst packing of the present invention.

[0020] Figure 3 It is the effect diagram of catalytic ozonation degradation of sulfamethoxazole by the integral catalyst packing prepared in Example 4 of the present invention.

[0021] Figure 4 It is the application schematic diagram of the present invention. Detailed Embodiments

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0023] The present invention adopts the excess impregnation method, uses foam ceramics as the carrier, and Co(NO 3 ) 2 ·6H 2 and Ce(NO 3 ) 3 ·6H 2 O as the mixed precursor solution, and the monolithic catalyst packing is obtained by impregnation loading and high-temperature calcination.

[0024] Example 1 The monolithic catalyst packing is prepared by the excess impregnation method.

[0025] The foam ceramic material comes from a certain ceramic company. The foam ceramics include the following components in mass percentage: 77.817% of Al 2 O 3 , 18.612% of SiO 2 , 1.361% of Na 2 O, 1.104% of CaO, 0.604% of SO 3 , 0.162% of MgO, 0.098% of K 2 O, 0.062% of P 2 O 5 , 0.052% of Fe 2 O 3 , 0.047% of TiO 2 , 0.038% of ZrO 2 , 0.028% of Cl, 0.015% of ZnO. The slurry is prepared according to the above components and then coated on the polyurethane foam. The polyurethane foam is carbonized at high temperature to finally obtain alumina foam ceramics.

[0026] Its specifications are shown in Table 1.

[0027] Table 1 Specifications and Dimensions of Foam Ceramic Materials Take the foam ceramic material carrier in a beaker, add deionized water, ultrasonicate for 20 min, and dry at 105 °C for 12 h for standby. Prepare Co(NO with a total metal concentration of 0.05 mol / L, 500 ml, and a Ce:Co molar ratio of 1:1 respectively.3 ) 2 ·6H 2 and Ce(NO 3 ) 3 ·6H 2 O mixed precursor solution. Place the washed and dried foam ceramic material into the above-prepared solution, take it out after ultrasonic treatment for 2 h. Use an ear bulb to blow off the remaining solution in the pores, and dry it at 105 °C for 12 h. Then set the muffle furnace temperature to 550 °C and calcine for 3 h to prepare the monolithic catalyst packing, whose appearance is as shown in Figure 1 、 2 shown.

[0028] Pack the prepared monolithic catalyst packing into a rotating packed bed for catalytic ozonation experiments. The application flow chart is as shown in Figure 4 shown. The liquid storage tank is filled with 1 L of sulfamethoxazole wastewater with a concentration of 100 mg / L, which is sent to the liquid inlet of the RPB by a circulating pump, and is evenly thrown into the inner cavity by a liquid distributor and discharged radially from the inner edge of the bed layer from the inside to the outside. The ozone generated by the ozone generator is metered by a gas flow meter and enters from the gas inlet of the RPB, passes through the packing bed layer from bottom to top, and cross-contacts with the sulfamethoxazole wastewater discharged from the inside to the outside. Under the catalytic action of the catalyst packing, it quickly undergoes an ozonation reaction with the sulfamethoxazole wastewater. Set the supergravity factor β to 30, the liquid flow rate Q L is 60 L / h, the gas flow rate Q G is 60 L / h, the gas-phase ozone concentration is 30 mg / L. The reacted liquid converges near the wall surface and returns to the liquid storage tank through the liquid outlet for cyclic reaction. The tail gas is absorbed by 2% KI solution and then discharged.

[0029] Take samples of the wastewater in Example 1 every 10 minutes, measure its TOC value, and calculate its mineralization rate. The results are shown in Table 2.

[0030] Table 2 Mineralization rate of sulfamethoxazole at different times in Example 1 Example 2 Take the foam ceramic in a beaker, add deionized water, ultrasonic for 20 min, and dry it at 105 °C for 12 h for standby. Prepare a Co(NO 3 ) 2 ·6H 2 and Ce(NO 3 ) 3 ·6H 2O mixed precursor solution. Place the washed and dried foam ceramic into the above-prepared solution, take it out after ultrasonic treatment for 2 h. Use an ear bulb to blow out the residual solution in the pores, and dry it at 105 °C for 12 h. Then set the muffle furnace temperature to 550 °C and calcine for 3 h to obtain the monolithic catalyst packing.

[0031] Fill the prepared monolithic catalyst packing into the rotating packed bed for catalytic ozonation experiments. The application flow chart is as Figure 4 shown. The storage tank is filled with 1 L of sulfamethoxazole wastewater with a concentration of 100 mg / L, which is sent to the liquid inlet of the RPB by a circulating pump, and is evenly thrown into the inner cavity by a liquid distributor and discharged radially from the inner edge to the outer edge of the bed layer. The ozone generated by the ozone generator is metered by a gas flow meter and enters from the gas inlet of the RPB, passes through the packing bed layer from bottom to top, and contacts the sulfamethoxazole wastewater discharged from the inside to the outside in a cross-flow manner. Under the catalytic action of the catalyst packing, it quickly undergoes an ozonation reaction with the sulfamethoxazole wastewater. Set the supergravity factor β to 30, the liquid flow rate Q L is 60 L / h, the gas flow rate Q G is 60 L / h, the gas-phase ozone concentration is 30 mg / L. The reacted liquid collects near the wall surface and returns to the storage tank for cyclic reaction from the liquid outlet. The tail gas is absorbed by 2% KI solution and then discharged.

[0032] Sample the wastewater in Example 2 every 10 minutes, measure its TOC value, and calculate its mineralization rate. The results are shown in Table 3.

[0033] Table 3 Mineralization rate of sulfamethoxazole at different times in Example 2 Example 3 Take the foam ceramic in a beaker, add deionized water, ultrasonic for 20 min, and dry at 105 °C for 12 h for standby. Prepare a Co(NO 3 ) 2 ·6H 2 and Ce(NO 3 ) 3 ·6H 2 O mixed precursor solution with a total metal concentration of 0.15 mol / L and a volume of 500 ml, where Ce:Co = 1:1. Place the washed and dried foam ceramic into the above-prepared solution, take it out after ultrasonic treatment for 2 h. Use an ear bulb to blow out the residual solution in the pores, and dry it at 105 °C for 12 h. Then set the muffle furnace temperature to 550 °C and calcine for 3 h to obtain the monolithic catalyst packing.

[0034] Fill the prepared monolithic catalyst packing into the rotating packed bed for catalytic ozonation experiments. The application flow chart is asFigure 4 As shown in the figure. The liquid storage tank is filled with 1 L of sulfamethoxazole wastewater with a concentration of 100 mg / L. It is sent into the liquid inlet of the RPB by a circulation pump, and is evenly thrown into the inner cavity by a liquid distributor, and is thrown out from the inner edge of the bed layer to the outside along the radial direction. The ozone generated by the ozone generator is metered by a gas flowmeter and enters from the gas inlet of the RPB, passes through the packing bed layer from bottom to top, and cross-flow contacts with the sulfamethoxazole wastewater thrown out from the inside to the outside. Under the catalytic action of the catalyst packing, it quickly undergoes an ozone oxidation reaction with the sulfamethoxazole wastewater. Set the supergravity factor β to 30, and the liquid flow rate Q L is 60 L / h, and the gas flow rate Q G is 60 L / h, the ozone concentration in the gas phase is 30 mg / L. The reacted liquid converges near the wall surface, returns to the liquid storage tank for cyclic reaction from the liquid outlet, and the tail gas is absorbed by 2% KI solution and then discharged.

[0035] Samples of the wastewater in Example 3 were taken every 10 minutes, the TOC value was measured, and the mineralization rate was calculated. The results are shown in Table 4.

[0036] Table 4 Mineralization rate of sulfamethoxazole at different times in Example 3 From the data of Examples 1, 2, 3 and Tables 2, 3, 4, it can be seen that: the monolithic catalyst packing prepared by this method has good ozone catalytic effect and high mineralization efficiency for sulfamethoxazole. By regulating the total concentration of different cobalt and cerium metal ions, it is easy to generate oxidation state mismatches, promote the formation of oxygen vacancies in the catalyst, and improve the catalytic activity of the catalyst.

[0037] Example 4 Take the foam ceramic in a beaker, add deionized water, ultrasonicate for 20 min, and dry at 105 °C for 12 h for standby. Prepare a mixed precursor solution with a total metal concentration of 0.15 mol / L, 500 ml, and Ce:Co = 1:1 of Co(NO 3 ) 2 ·6H 2 and Ce(NO 3 ) 3 ·6H 2 O. Place the washed and dried foam ceramic in the above-prepared solution, take it out after ultrasonication for 2 h. Use an ear bulb to blow out the residual solution in the pores, and dry at 105 °C for 12 h. Then set the muffle furnace temperature to 550 °C and calcine for 3 h to obtain the monolithic catalyst packing.

[0038] The prepared monolithic catalyst packing was filled in a rotating packed bed for a catalytic ozonation experiment. The application flow chart is as Figure 4As shown in the figure. The liquid storage tank is filled with 1 L of sulfamethoxazole wastewater with a concentration of 100 mg / L, which is sent into the liquid inlet of the RPB by a circulating pump. After passing through the liquid distributor, it is evenly thrown into the inner cavity and discharged radially from the inner edge of the bed layer from the inside to the outside. The ozone generated by the ozone generator is metered by a gas flow meter and enters from the gas inlet of the RPB, passing through the packing bed layer from bottom to top, and making a cross-flow contact with the sulfamethoxazole wastewater discharged from the inside to the outside. Under the catalytic action of the catalyst packing, it quickly undergoes an ozonation reaction with the sulfamethoxazole wastewater. Adjust the supergravity factor β to 30, and the liquid flow rate Q L is 60 L / h, and the gas flow rate Q G is 60 L / h, the ozone concentration in the gas phase is 30 mg / L. The reacted liquid converges near the wall surface and returns to the liquid storage tank for cyclic reaction from the liquid outlet. The tail gas is absorbed by 2% KI solution and then discharged. The above experiments are repeated under the conditions of not filling the packing and filling the unloaded metal foam ceramic packing respectively.

[0039] Samples of the wastewater in Example 4 are taken every 10 minutes to measure its TOC value and calculate the mineralization rate of sulfamethoxazole in the wastewater. The results are as Figure 3 shown: The results show that the presence of the prepared monolithic catalyst can significantly improve the TOC removal rate. Among them, the TOC removal rate of the monolithic catalyst packing system is the highest, reaching 67.93%. The η TOC value of the single ozone system only reaches 42.75% at 60 min, indicating that in the absence of a catalyst, it is difficult for refractory organic pollutants to be completely mineralized. In comparison, the η TOC value of the monolithic catalyst packing system has been showing a rapid upward trend, and it has increased by about 34.20% within 10 - 20 min η TOC . The η TOC at 20 min is twice that of the single ozone system and 1.20 times that of the unloaded metal foam ceramic system. The monolithic catalyst packing system has greatly improved the mineralization effect of sulfamethoxazole wastewater compared with the single ozone and the foam ceramic packing filled with unloaded metal. It shows that the foam ceramic loaded with Co and Ce oxides can promote the rapid decomposition of ozone molecules into ·OH, thereby improving the catalytic ozonation efficiency of the foam ceramic carrier for sulfamethoxazole. The mineralization rates of sulfamethoxazole in different systems can also show that the monolithic catalyst packing enables the liquid to flow along a relatively regular route, can better disperse the liquid droplets, further reduce the size of the dispersed liquid droplets, strengthen the gas-liquid mass transfer process, and improve the ozone utilization rate.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a monolithic catalyst packing, characterized in that: The steps include: S1. Wash the foam ceramic material in deionized water with ultrasonic. S2, drying the foam ceramic material obtained in S1; S3, excessively immersing the foam ceramic material obtained in S2 in a mixed precursor solution of Co(NO3)2·6H2O and Ce(NO3)3·6H2O; S4, removing the residual liquid in the foam ceramic pores obtained in S3 and drying; S5. The foam ceramic obtained in S4 is transferred into a muffle furnace for calcination, and then cooled to obtain a monolithic catalyst.

2. The method for preparing a monolithic catalyst packing according to claim 1, characterized in that: The ultrasonic time described in S1 was 20 min.

3. The method for preparing a monolithic catalyst packing according to claim 1, characterized in that: The drying temperature described in S2 is 105° C. and the drying time is 12 h.

4. The method for preparing a monolithic catalyst packing according to claim 1, characterized in that: The molar ratio of Co and Ce in the mixed precursor solution described in S3 is 1:1, and the total metal concentration is 0.15 mol / L.

5. The method for preparing a monolithic catalyst packing according to claim 1, characterized in that: The drying temperature described in S4 is 105°C and the drying time is 12 h.

6. The method for preparing a monolithic catalyst packing according to claim 1, characterized in that: The calcination temperature described in S5 is 550°C and the time is 3 h.

7. A monolithic catalyst filler prepared by the preparation method of claim 1 is used in a rotating packed bed to heterogeneously catalyze ozone degradation of sulfamethoxazole wastewater, wherein the monolithic catalyst filler is loaded in the rotor of the rotating packed bed as a monolithic annular filler.

8. The use of a monolithic catalyst packing according to claim 7, characterized in that: The sulfamethoxazole wastewater concentration is 100 mg / L and the volume is 1L.

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