Ceramic catalytic filter tube, preparation method and application

Abstract

The present invention discloses a ceramic catalytic filter tube, a preparation method, and applications. The preparation method comprises the following steps: S1: preparing an Fe-Ce / TiO2 diatomic catalyst; S2: uniformly mixing ceramic fibers, the Fe-Ce / TiO2 diatomic catalyst, a binder, and a surfactant, and then extruding the resulting mixture to form a molded ceramic catalytic filter tube; S3: aging, drying, and anaerobic calcining the molded mixture to produce a formed ceramic catalytic filter tube. The ceramic catalytic filter tube of the present invention can achieve high-efficiency catalytic purification of flue gas under medium and low temperature operating conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas purification, and in particular to a ceramic catalytic filter tube, a preparation method and an application thereof. Background Art

[0002] In recent years, environmental protection has gradually shifted from extensive pollution control to precise and coordinated pollution control. The SNCR denitrification process can no longer meet local environmental protection requirements, and has gradually exposed problems such as low denitrification efficiency, large ammonia consumption, and large ammonia escape. It can easily cause corrosion of production facilities and equipment, and increase production energy consumption (including coal consumption and electricity consumption) and operating costs.

[0003] At the same time, although the use of separate SCR technology is highly efficient, based on the actual operating conditions of cement kilns (general operating temperatures are between 280-350°C), the exhaust gas temperature is between 150-240°C and is accompanied by a high content of dust. The utilization rate of its catalyst is also very low, which is not conducive to the overall energy conservation and carbon emission reduction of the cement kiln. In addition, the flue gas contains a certain degree of VOCs, which requires improved treatment standards.

[0004] Therefore, the ceramic catalytic filter tube designed to cover medium and low temperatures and a wide temperature range can meet the market demand for "carbon peak and carbon neutrality" of industrial flue gas, and has broad industrialization prospects. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a ceramic catalytic filter tube, a preparation method and an application, which can meet the requirements of efficient catalytic purification of flue gas under medium and low temperature conditions.

[0006] The preparation method of the ceramic catalytic filter tube proposed by the present invention comprises the following steps:

[0007] S1: Preparation of Fe-Ce / TiO2 diatomic catalyst;

[0008] S2: The ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant are uniformly mixed and then extruded to obtain a green body;

[0009] S3: The embryo is aged, dried and calcined in the absence of oxygen to obtain a formed ceramic catalytic filter tube.

[0010] Preferably, the steps of the method for preparing the Fe-Ce / TiO2 diatomic catalyst in S1 are as follows:

[0011] S11: dispersing a cerium source, an iron source, and a titanium source in anhydrous ethanol to obtain a precursor solution;

[0012] S12: The precursor solution is injected into a tubular combustion furnace using hydrogen as fuel. The precursor solution is completely burned and evaporated under the condition of oxygen being introduced to obtain a solid Fe-Ce / TiO2 diatomic catalyst.

[0013] Preferably, in S11, the cerium source is cerium nitrate, the iron source is ferric nitrate, and the titanium source is tetrabutyl titanate; and the mass ratio of the cerium source, the iron source, and the titanium source is 100-120:20-33:1.

[0014] Preferably, the flow rate of hydrogen in S12 is 2.0-3.0 L / min; the pressure of oxygen is 1.0 bar, and the flow rate is 13.0-15.0 L / min.

[0015] Preferably, the mass ratio of ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant in S2 is 1:62.5-125:5-10:2-8.

[0016] Preferably, the adhesive in S2 is cyanoacrylate or polyacrylate adhesive.

[0017] Preferably, the surfactant in S2 is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 3:1-9.

[0018] Preferably, in S3, the aging temperature is room temperature and the time is 12-24 hours; the drying temperature is 60-100° C. and the time is 6-12 hours; and the oxygen-free calcination temperature is 300-400° C. and the time is 24-36 hours.

[0019] The present invention provides a ceramic catalytic filter tube prepared by the method mentioned above.

[0020] The present invention provides an application of the ceramic catalytic filter tube in flue gas purification.

[0021] Beneficial technical effects of the present invention:

[0022] The precursor prepared from cerium source, iron source and titanium source in the present invention is injected into a tubular combustion furnace with hydrogen as fuel and completely burned and evaporated. The resulting diatomic catalyst has high particle size dispersion, high specific surface area and non-porous structure, which has a good effect on improving catalytic performance and sintering resistance. Traditional high-temperature calcination has uneven calcination zone atmosphere, incomplete firing, and the resulting catalyst has the disadvantages of uneven particle size, unstable crystal form and high energy consumption. The catalytic performance of the diatomic catalyst is also different from that of the preparation method of the present invention.

[0023] The present invention prepares a catalytic filter tube by mixing ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant. The catalytic filter tube can simultaneously meet the requirements of catalysis and dust removal. The denitrification and VOCs removal efficiency can reach more than 90% in the medium and low temperature range of 150-230℃, so that the VOCs emission concentration, dust emission concentration and nitrogen oxide emission concentration all meet the emission standards, and the VOCs emission concentration does not exceed 20mg / Nm3 , dust emission concentration does not exceed 5mg / Nm 3 , nitrogen oxide emission concentration does not exceed 50mg / Nm 3 , which can fully meet the catalytic needs under medium and low temperature conditions.

[0024] The surfactant of the present invention can well integrate the Fe-Ce / TiO2 diatomic catalyst with the ceramic fiber, making the distribution more uniform and stretched, so that the entire specific surface of the catalytic ceramic tube prepared participates in denitrification and oxidation of VOCs, thereby improving the catalytic utilization rate; in addition, the surfactant is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine, which has a synergistic promoting effect on improving the performance of the catalytic filter tube. DETAILED DESCRIPTION

[0025] The present invention will be further explained below with reference to specific embodiments.

[0026] Example 1

[0027] The preparation method of the ceramic catalytic filter tube proposed in this embodiment comprises the following steps:

[0028] S1: Add 120 g of cerium nitrate, 33 g of ferric nitrate and 1 g of tetrabutyl titanate to anhydrous ethanol and stir continuously until the solid is completely dissolved to prepare a Fe-Ce / TiO2 catalyst precursor solution.

[0029] S2: The precursor solution containing the Fe-Ce / TiO2 catalyst is injected into the tubular combustion furnace at an injection rate of 2.5 mL / min, and at the same time, oxygen with a pressure of 1.0 bar is continuously introduced into the tubular combustion furnace, and the flow rates of the fuel hydrogen and the oxygen introduced into the tubular combustion furnace are maintained at 3.0 L / min and 15.0 L / min respectively; after the precursor solution containing the Fe-Ce / TiO2 catalyst is completely burned and evaporated, a solid Fe-Ce / TiO2 diatomic catalyst is obtained; it has been measured that the combustion temperature of the tubular combustion furnace is 600°C and the processing time is 1 hour.

[0030] S3: Grinding the solid Fe-Ce / TiO2 diatomic catalyst in a ball mill until the catalyst particle size reaches 5 μm.

[0031] S4: The ground catalyst particles with a particle size of 5 μm were poured into a mixer and mixed with ceramic fibers with a particle size of 5 μm for 4 hours at a rotation speed of 110 rpm.

[0032] S5: adding cyanoacrylate binder and surfactant to the mixed raw material of the catalyst and ceramic fiber respectively, and continuing to mix for 8 hours using a mixer at a speed of 550 rpm.

[0033] S6: The mixed catalyst and ceramic fiber raw material are placed in an extruder, and a ceramic catalytic filter tube embryo with a diameter of 150 mm, a length of 3000 mm, and a thickness of 15 mm is prepared under an extrusion pressure of 3 MPa.

[0034] S7: The embryo body is aged at room temperature for 18 hours, then microwave-dried at 80° C. for 8 hours, and finally calcined at 350° C. for 30 hours in an oxygen-free environment to obtain a formed ceramic catalytic filter tube.

[0035] The mass ratio of ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant is 1:90:8:5.

[0036] The surfactant is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 1:1.

[0037] Example 2

[0038] The preparation method of the ceramic catalytic filter tube proposed in this embodiment comprises the following steps:

[0039] S1: Add 120 g of cerium nitrate, 33 g of ferric nitrate and 1 g of tetrabutyl titanate to anhydrous ethanol and stir continuously until the solid is completely dissolved to prepare a Fe-Ce / TiO2 catalyst precursor solution.

[0040] S2: Inject the precursor solution containing the Fe-Ce / TiO2 catalyst into the tubular combustion furnace at an injection rate of 2.5 mL / min, and at the same time continuously introduce oxygen at a pressure of 1.0 bar into the tubular combustion furnace, and maintain the flow rates of the fuel hydrogen and the oxygen introduced into the tubular combustion furnace at 3.0 L / min and 15.0 L / min respectively; after the precursor solution containing the Fe-Ce / TiO2 catalyst is completely burned and evaporated, a solid Fe-Ce / TiO2 diatomic catalyst is obtained.

[0041] S3: grinding the solid Fe-Ce / TiO2 diatomic catalyst in a ball mill until the catalyst particle size reaches 5 μm;

[0042] S4: The ground catalyst particles with a particle size of 5 μm were poured into a mixer and mixed with ceramic fibers with a particle size of 5 μm for 4 hours at a rotation speed of 110 rpm.

[0043] S5: adding cyanoacrylate binder and surfactant to the mixed raw material of the catalyst and ceramic fiber respectively, and continuing to mix for 8 hours using a mixer at a speed of 550 rpm.

[0044] S6: The mixed catalyst and ceramic fiber raw material are placed in an extruder, and a ceramic catalytic filter tube embryo with a diameter of 150 mm, a length of 3000 mm, and a thickness of 15 mm is prepared under an extrusion pressure of 3 MPa.

[0045] S7: The embryo body is aged at room temperature for 18 hours, then microwave-dried at 80° C. for 8 hours, and finally calcined at 350° C. for 30 hours in an oxygen-free environment to obtain a formed ceramic catalytic filter tube.

[0046] The mass ratio of ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant is 1:62.5:5:2.

[0047] The surfactant is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 3:1.

[0048] Example 3

[0049] The preparation method of the ceramic catalytic filter tube proposed in this embodiment comprises the following steps:

[0050] S1: Add 120 g of cerium nitrate, 33 g of ferric nitrate and 1 g of tetrabutyl titanate to anhydrous ethanol and stir continuously until the solid is completely dissolved to prepare a Fe-Ce / TiO2 catalyst precursor solution.

[0051] S2: Inject the precursor solution containing the Fe-Ce / TiO2 catalyst into the tubular combustion furnace at an injection rate of 2.5 mL / min, and at the same time continuously introduce oxygen at a pressure of 1.0 bar into the tubular combustion furnace, and maintain the flow rates of the fuel hydrogen and the oxygen introduced into the tubular combustion furnace at 3.0 L / min and 15.0 L / min respectively; after the precursor solution containing the Fe-Ce / TiO2 catalyst is completely burned and evaporated, a solid Fe-Ce / TiO2 diatomic catalyst is obtained.

[0052] S3: grinding the solid Fe-Ce / TiO2 diatomic catalyst in a ball mill until the catalyst particle size reaches 5 μm;

[0053] S4: The ground catalyst particles with a particle size of 5 μm were poured into a mixer and mixed with ceramic fibers with a particle size of 5 μm for 4 hours at a rotation speed of 110 rpm.

[0054] S5: adding cyanoacrylate binder and surfactant to the mixed raw material of the catalyst and ceramic fiber respectively, and continuing to mix for 8 hours using a mixer at a speed of 550 rpm.

[0055] S6: The mixed catalyst and ceramic fiber raw material are placed in an extruder, and a ceramic catalytic filter tube embryo with a diameter of 150 mm, a length of 3000 mm, and a thickness of 15 mm is prepared under an extrusion pressure of 3 MPa.

[0056] S7: The embryo body is aged at room temperature for 18 hours, then microwave-dried at 80° C. for 8 hours, and finally calcined at 350° C. for 30 hours in an oxygen-free environment to obtain a formed ceramic catalytic filter tube.

[0057] The mass ratio of ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant is 1:125:10:8.

[0058] The surfactant is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 1:3.

[0059] Comparative Example 1

[0060] The preparation method of the ceramic catalytic filter tube proposed in this scheme has the following steps:

[0061] S1: Add 120 g of cerium nitrate, 33 g of ferric nitrate and 1 g of tetrabutyl titanate to anhydrous ethanol and stir continuously until the solid is completely dissolved to prepare a Fe-Ce / TiO2 catalyst precursor solution.

[0062] S2: The precursor solution was dried, ground and calcined at a temperature of 600°C for 1 hour (the same temperature and time as the tubular combustion furnace treatment in Example 1) to obtain a solid Fe-Ce / TiO2 diatomic catalyst.

[0063] S3: Grinding the solid Fe-Ce / TiO2 diatomic catalyst in a ball mill until the catalyst particle size reaches 5 μm.

[0064] S4: The ground catalyst particles with a particle size of 5 μm were poured into a mixer and mixed with ceramic fibers with a particle size of 5 μm for 4 hours at a rotation speed of 110 rpm.

[0065] S5: adding cyanoacrylate binder and surfactant to the mixed raw material of the catalyst and ceramic fiber respectively, and continuing to mix for 8 hours using a mixer at a speed of 550 rpm.

[0066] S6: The mixed catalyst and ceramic fiber raw material are placed in an extruder, and a ceramic catalytic filter tube embryo with a diameter of 150 mm, a length of 3000 mm, and a thickness of 15 mm is prepared under an extrusion pressure of 3 MPa.

[0067] S7: The embryo body is aged at room temperature for 18 hours, then microwave-dried at 80° C. for 8 hours, and finally calcined at 350° C. for 30 hours in an oxygen-free environment to obtain a formed ceramic catalytic filter tube.

[0068] The mass ratio of ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant is 1:90:8:5.

[0069] The surfactant is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 1:1.

[0070] Comparative Example 2

[0071] The surfactant in this solution is lauroyl lysine surfactant, and the other conditions are the same as those in Example 1.

[0072] Comparative Example 3

[0073] The surfactant in this solution is dodecyl dimethyl hydroxypropyl betaine phosphate, and the other conditions are the same as those in Example 1.

[0074] The catalytic performance of the ceramic catalytic filter tubes prepared in Examples 1-3 and Comparative Examples 1-3 was tested under the following test conditions: 500 ppm NO x , 500ppm NH3, 1000ppm chlorobenzene, 10% O2, 89% N2, space velocity 50000h - The test temperatures are 150℃, 180℃, 210℃ and 240℃ respectively. The test results are shown in Table 1.

[0075] Table 1 Test results of catalytic performance of ceramic catalytic filter tubes

[0076]

[0077] As can be seen from the test results of Examples 1-3 in Table 1, the ceramic catalytic filter tube prepared by the present invention can still stabilize the denitration and VOC removal efficiency at over 90% even at a low temperature of 150°C, and in particular, at a medium temperature of 240°C, the denitration and VOC removal efficiency can reach 100%. As can be seen from the test results of Example 1 and Comparative Example 1, the precursor prepared by the present invention using cerium source, iron source, and titanium source is injected into a tubular combustion furnace fueled by hydrogen and completely burned and evaporated. The resulting diatomic catalyst has a high particle size dispersion, a high specific surface area, and a non-porous structure, which has a good effect on improving catalytic performance and sintering resistance. However, traditional high-temperature calcination has uneven calcination zone atmosphere, incomplete firing, and the resulting catalyst has the disadvantages of uneven particle size, unstable crystal form, and high energy consumption. The catalytic performance of the diatomic catalyst is also different from that of the preparation method of the present invention. It can be seen from the test results of Example 1 and Comparative Examples 2-3 that the surfactant of the present invention can well integrate the Fe-Ce / TiO2 diatomic catalyst with the ceramic fiber, making the distribution more uniform and stretched, so that the entire surface of the catalytic ceramic tube prepared participates in denitrification and oxidation of VOCs, thereby improving the catalytic utilization rate; in addition, the surfactant is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine, which has a synergistic promoting effect on improving the performance of the catalytic filter tube.

Claims

1. A method for preparing a ceramic catalytic filter tube for flue gas purification, characterized in that: The steps are as follows: S1: Preparation of Fe-Ce / TiO2 diatomic catalyst; S2: The ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant are uniformly mixed and then extruded to obtain a green body; S3: The embryo is aged, dried and sintered in an oxygen-free environment to obtain a formed ceramic catalytic filter tube; The steps for preparing the Fe-Ce / TiO2 diatomic catalyst in S1 are as follows: S11: dispersing a cerium source, an iron source, and a titanium source in anhydrous ethanol to obtain a precursor solution; S12: injecting the precursor solution into a tubular combustion furnace fueled by hydrogen, and completely burning and evaporating the precursor solution under the condition of oxygen flow, thereby obtaining a solid Fe-Ce / TiO2 diatomic catalyst; The surfactant in S2 is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 3:1-9; The mass ratio of ceramic fiber, Fe-Ce / TiO2 diatomic catalyst, binder and surfactant in S2 is 1:62.5-125:5-10:2-8; The adhesive in S2 is cyanoacrylate or polyacrylate adhesive.

2. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: In S11, the cerium source is cerium nitrate, the iron source is ferric nitrate, and the titanium source is tetrabutyl titanate; the mass ratio of the cerium source, the iron source, and the titanium source is 100-120:20-33:

1.

3. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: The flow rate of hydrogen in S12 is 2.0-3.0 L / min; the pressure of oxygen is 1.0 bar, and the flow rate is 13.0-15.0 L / min.

4. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: In S3, the aging temperature is room temperature and the time is 12-24 hours; the drying temperature is 60-100°C and the time is 6-12 hours; the oxygen-free calcination temperature is 300-400°C and the time is 24-36 hours.

5. A ceramic catalytic filter tube prepared by the method according to any one of claims 1 to 4.

6. Use of the ceramic catalytic filter tube according to claim 5 in flue gas purification.

Images