Ceramic catalytic filter tube, preparation method and application

Abstract

The invention discloses a ceramic catalytic filter tube as well as a preparation method and application thereof. The preparation method of the ceramic catalytic filter tube comprises the following steps: S1, preparing a Fe-Ce / TiO2 diatomic catalyst; s2, uniformly mixing ceramic fibers, a Fe-Ce / TiO2 diatomic catalyst, a binder and a surfactant, and preparing a blank through an extruder; and S3, aging, drying and anaerobic roasting the blank body to obtain the formed ceramic catalytic filter tube. The ceramic catalytic filter tube provided by the invention can meet efficient catalytic purification of flue gas under medium and low temperature working conditions.

Description

Technical Field

[0001] The 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, with the continuous introduction of ultra-low emission standards and implementation plans in various regions, 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, which can easily cause corrosion of production facilities and equipment, increase production energy consumption (including coal consumption and electricity consumption) and operating costs.

[0003] At the same time, although the use of a single SCR technology is highly efficient, based on the actual operating conditions of cement kilns (generally 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 the 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.

[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 an embryonic body is obtained by an extruder;

[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: Inject the precursor solution 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; 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 by the present invention using cerium source, iron source and titanium source is injected into a tubular combustion furnace using hydrogen as fuel and completely burned and evaporated, and the obtained 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; while the traditional high-temperature calcination has uneven calcination zone atmosphere, incomplete firing, uneven catalyst 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 meet the requirements of catalysis and dust removal at the same time. The denitration and VOCs removal efficiency can reach more than 90% in the medium and low temperature range of 150-230°C, 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 / Nm 3 , dust emission concentration does not exceed 5mg / Nm 3 , the 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 embed 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 prepared catalytic ceramic tube participates in denitration 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 in conjunction with specific embodiments.

[0026] Example 1

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

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

[0029] S2: Inject the precursor solution containing Fe-Ce / TiO2 catalyst into the tubular combustion furnace at an injection rate of 2.5mL / min, and continuously introduce oxygen at a pressure of 1.0bar into the tubular combustion furnace at the same time, and maintain the flow rates of fuel hydrogen and oxygen introduced into the tubular combustion furnace at 3.0L / min and 15.0L / min respectively; after the precursor solution containing 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℃ and the processing time is 1h.

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

[0031] S4: Pour the ground catalyst particles with a particle size of 5 μm into a mixer and mix 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 rotation speed of 550 rpm.

[0033] S6: The mixed catalyst and ceramic fiber mixed raw materials 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 the absence of oxygen to finally obtain a formed ceramic catalytic filter tube.

[0035] Among them, 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 has the following steps:

[0039] S1: Add 120 g of cerium nitrate, 33 g of iron nitrate and 1 g of tetrabutyl titanate into 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 continuously introduce oxygen at a pressure of 1.0 bar into the tubular combustion furnace at the same time, and maintain the flow rates of the fuel hydrogen and 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: Pour the ground catalyst particles with a particle size of 5 μm into a mixer and mix 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 rotation speed of 550 rpm.

[0044] S6: The mixed catalyst and ceramic fiber mixed raw materials 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 the absence of oxygen to finally obtain a formed ceramic catalytic filter tube.

[0046] Among them, 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 has the following steps:

[0050] S1: Add 120 g of cerium nitrate, 33 g of iron nitrate and 1 g of tetrabutyl titanate into 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 continuously introduce oxygen at a pressure of 1.0 bar into the tubular combustion furnace at the same time, and maintain the flow rates of the fuel hydrogen and 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: Pour the ground catalyst particles with a particle size of 5 μm into a mixer and mix 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 rotation speed of 550 rpm.

[0055] S6: The mixed catalyst and ceramic fiber mixed raw materials 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 the absence of oxygen to finally obtain a formed ceramic catalytic filter tube.

[0057] Among them, 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 iron nitrate and 1 g of tetrabutyl titanate into 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 is 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: Grind the solid Fe-Ce / TiO2 diatomic catalyst in a ball mill until the catalyst particle size reaches 5 μm.

[0064] S4: Pour the ground catalyst particles with a particle size of 5 μm into a mixer and mix 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 rotation speed of 550 rpm.

[0066] S6: The mixed catalyst and ceramic fiber mixed raw materials 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 the absence of oxygen to finally obtain a formed ceramic catalytic filter tube.

[0068] Among them, 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 scheme 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 scheme is dodecyl dimethyl hydroxypropyl phosphate betaine, 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°C, 180°C, 210°C, and 240°C respectively. The test results are shown in Table 1.

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

[0076]

[0077] It can be seen from the test results of Examples 1-3 in Table 1 that the ceramic catalytic filter tube prepared by the present invention can still stabilize the denitration and de-VOCs efficiency at more than 90% even at a low temperature of 150°C, especially at a medium temperature of 240°C, the denitration and de-VOCs efficiency can reach 100%. It can be seen from the test results of Example 1 and Comparative Example 1 that the precursor prepared by the present invention with cerium source, iron source and titanium source is injected into a tubular combustion furnace with hydrogen as fuel and completely burned and evaporated, and the obtained 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; while the traditional high-temperature calcination, calcination zone atmosphere is uneven, firing is incomplete, the obtained catalyst particle size is uneven, the crystal form is unstable and the energy consumption is high. 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 embed 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 obtained 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 in improving the performance of the catalytic filter tube.

Claims

1. A ceramic catalytic filter tube, a preparation method and an application thereof, 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 an embryonic body is obtained by an extruder; S3: The embryo is aged, dried and calcined in the absence of oxygen to obtain a formed ceramic catalytic filter tube.

2. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: The method 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: Inject the precursor solution 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.

3. The method for preparing a ceramic catalytic filter tube according to claim 2, 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.

4. The method for preparing a ceramic catalytic filter tube according to claim 2, 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.

5. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: 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.

6. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: The adhesive in S2 is cyanoacrylate or polyacrylate.

7. The method for preparing a ceramic catalytic filter tube according to claim 1, characterized in that: The surfactant in S2 is composed of lauroyl lysine surfactant and dodecyl dimethyl hydroxypropyl phosphate betaine in a mass ratio of 3:1-9.

8. 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.

9. A ceramic catalytic filter tube prepared by the method according to any one of claims 1 to 8.

10. Use of the ceramic catalytic filter tube according to claim 9 in flue gas purification.

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