A sintering flue gas CO catalyst and its preparation method

Abstract

The present invention provides a sintering flue gas CO catalyst and a preparation method thereof, belonging to the technical field of flue gas purification. The structural formula of the catalyst is Pt-Ce-Fe3O4 / TiO2-CNT, and it is prepared from raw materials comprising the following parts by mass: 0.01 to 0.1 part of PtCl4, 0.05 to 0.15 part of Ce(NO3)3, 0.5 to 1.5 parts of FeCl3, 15 to 150 parts of TiO2, and 10 to 30 parts of carbon nanotubes. When the sintering flue gas catalyst provided by the present invention does not contain SO2, the CO removal rate is as high as 98.56%. When there is SO2, the removal rate only drops by about 10%, and it has excellent anti-poisoning performance. When applied between the desulfurization and denitrification processes, the heat released by the conversion of CO into CO2 is sufficient to raise the flue gas temperature by more than 50 °C, saving a large amount of energy consumption for the denitrification process.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas purification, and in particular to a sintering flue gas CO catalyst and a preparation method thereof. Background Art

[0002] At present, the reduction of pollutants in sintering flue gas mainly focuses on desulfurization and denitrification processes, with less research on CO reduction. The relatively high concentration of CO emissions (6000 - 12000 mg / m 3 ) not only causes environmental pollution, but also results in the waste of the latent heat of CO, and does not meet the development requirements of carbon emission reduction. In the NH3-SCR denitrification process, the denitrification temperature (180 - 280 °C) is higher than the sintering flue gas temperature (80 - 160 °C). Therefore, if CO is converted into CO2 before flue gas denitrification, the released heat is sufficient to increase the flue gas temperature by more than 50 °C, thus saving a large amount of energy consumption for the subsequent denitrification process.

[0003] Sintering flue gas usually contains a large amount of SO2 and H2O at the same time. SO2 will poison the catalyst, and the poisoning effect will be enhanced under the condition of H2O. For example, Zhou Hao et al. (Performance comparison of Pt-coated honeycomb metal and Ce-modified Fe2O3 for CO catalysis [J]. Journal of Engineering Science, 2020, 42(1): 70 - 77) studied the performance of Pt-coated honeycomb metal catalyst for removing CO from iron ore sintering flue gas. When at 180 °C, in the presence of 143 mg / m 3 and 11.7% water vapor, its CO conversion rate is 48.6%, which is 18.9% lower than that under the condition of no water and no sulfur.

[0004] Therefore, in order to achieve the reduction of CO in the environment and the utilization of the latent heat of CO in the process, there is an urgent need for a CO catalyst with resistance to SO2 and H2O poisoning. Summary of the Invention

[0005] The purpose of the present invention is to provide a sintering flue gas CO catalyst and a preparation method thereof, so as to solve the problems of low catalytic efficiency of the existing CO catalyst and poor resistance to SO2 and H2O poisoning.

[0006] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a sintering flue gas CO catalyst with the structural formula of Pt-Ce-Fe3O4 / TiO2-CNT.

[0008] Preferably, the sintering flue gas CO catalyst is prepared from raw materials comprising the following mass fractions:

[0009] 0.01 - 0.1 parts of PtCl4, 0.05 - 0.15 parts of Ce(NO3)3, 0.5 - 1.5 parts of FeCl3, 15 - 150 parts of TiO2, 10 - 30 parts of carbon nanotubes.

[0010] The present invention also provides a preparation method of the sintering flue gas CO catalyst, comprising the following steps:

[0011] (1) Dissolve PtCl4, Ce(NO3)3 and FeCl3 in water to obtain a precursor solution;

[0012] (2) Immerse TiO2 and carbon nanotubes in the precursor solution, take them out and calcine to obtain the sintering flue gas CO catalyst.

[0013] Preferably, in step (1), the mass - volume ratio of PtCl4 to water is 0.01 - 0.1 g: 80 - 400 mL.

[0014] Preferably, in step (2), the temperature of the immersion is 60 - 80 °C.

[0015] Preferably, in step (2), the time of the immersion is 1 - 4 h.

[0016] Preferably, in step (2), the temperature of the calcination is 280 - 350 °C.

[0017] Preferably, in step (2), the time of the calcination is 3 - 6 h.

[0018] The present invention has the following beneficial effects

[0019] The present invention provides a sintering flue gas CO catalyst with the structural formula of Pt - Ce - Fe3O4 / TiO2 - CNT, which is prepared from raw materials comprising the following mass parts: 0.01 - 0.1 parts of PtCl4, 0.05 - 0.15 parts of Ce(NO3)3, 0.5 - 1.5 parts of FeCl3, 15 - 150 parts of TiO2, 10 - 30 parts of carbon nanotubes. The components of the present invention contain Pt, having good anti - sulfidation ability. Under high - oxidation and sulfidation conditions, sulfates are less likely to form on the Pt surface, and it has excellent CO catalytic ability, capable of quickly converting CO into CO2. The reaction mechanism is as follows: CO is first adsorbed on the surface of Pt species, and O2 in the flue gas will be adsorbed on the catalyst surface to form adsorbed oxygen O α O α can oxidize CO on the surface of Pt species into CO2, realizing the CO catalytic oxidation process.

[0020] Ce, as one of the catalyst components, can increase the acidic sites on the catalyst surface after combining with Pt, hinder the adsorption of acidic SO2, and can adsorb a large amount of O αAfter binding with Pt, it can promote the conversion of CO to CO2. When contacting with SO2, it can preferentially bind with SO2 to form cerium sulfate, thus protecting the active sites on the Pt surface. At the same time, it can also decompose the generated sulfate, improving the SO2 resistance level of the catalyst.

[0021] Adding Fe increases the specific surface area of the catalyst and the dispersion degree of the active components, improves the efficiency of the catalyst for CO2 removal, and Fe is not easily affected by SO2 and H2O. It can inhibit the sulfation of metal atoms in the catalyst and enhance the poisoning resistance performance to SO2 and H2O.

[0022] TiO2 has a large specific surface area, and metal atoms have good dispersion on its surface, effectively improving the catalytic activity and poisoning resistance. It can also promote the dissociation reaction of water molecules on the surface, and the dissociation products promote the oxidation of CO.

[0023] Carbon nanotubes (CNTs) have an ordered surface structure, have a strong adsorption effect and antioxidant effect on SO2. Adding carbon nanotubes (CNTs) on the basis of the TiO2 support can effectively improve the poisoning resistance performance of the catalyst, and at the same time improve the thermal stability of the catalyst, enabling TiO2 to still maintain a high catalytic activity at high temperatures.

[0024] The working temperature of the sintering flue gas CO catalyst provided by the present invention is 200 - 300 °C. When there is no SO2, the CO removal rate reaches 98.56%. When there is SO2, the CO removal rate only drops by about 10%. It has excellent poisoning resistance. Applied between the desulfurization and denitrification processes, the heat released by the conversion of CO to CO2 is sufficient to raise the flue gas temperature by more than 50 °C, saving a large amount of energy consumption for the denitrification process. Detailed implementation mode

[0025] The present invention provides a sintering flue gas CO catalyst with a structural formula of Pt-Ce-Fe3O4 / TiO2-CNT.

[0026] In the present invention, the sintering flue gas CO catalyst is prepared from raw materials comprising the following parts by mass:

[0027] PtCl4 0.01 - 0.1 part, Ce(NO3)3 0.05 - 0.15 part, FeCl3 0.5 - 1.5 parts, TiO2 15 - 150 parts, carbon nanotubes 10 - 30 parts.

[0028] In the present invention, the mass part of PtCl4 is preferably 0.02 - 0.09 part, more preferably 0.03 - 0.08 part, and still more preferably 0.04 - 0.06 part.

[0029] In the present invention, the mass fraction of Ce(NO3)3 is preferably 0.06 - 0.14 parts, more preferably 0.07 - 0.13 parts, and even more preferably 0.09 - 0.12 parts.

[0030] In the present invention, the mass fraction of FeCl3 is preferably 0.7 - 1.3 parts, more preferably 0.8 - 1.2 parts, and even more preferably 0.9 - 1.1 parts.

[0031] In the present invention, the mass fraction of TiO2 is preferably 30 - 135 parts, more preferably 40 - 125 parts, and even more preferably 60 - 105 parts.

[0032] In the present invention, the mass fraction of carbon nanotubes is preferably 12 - 28 parts, more preferably 15 - 25 parts, and even more preferably 18 - 22 parts.

[0033] The present invention also provides a method for preparing the sintered flue gas CO catalyst, comprising the following steps:

[0034] (1) Dissolve PtCl4, Ce(NO3)3 and FeCl3 in water to obtain a precursor solution;

[0035] (2) Immerse TiO2 and carbon nanotubes in the precursor solution, take them out and calcine to obtain the sintered flue gas CO catalyst.

[0036] In the present invention, in step (1), the mass - volume ratio of PtCl4 to water is preferably 0.01 - 0.1 g:80 - 400 mL, more preferably 0.03 - 0.08 g:150 - 350 mL, and even more preferably 0.04 - 0.06 g:200 - 300 mL.

[0037] In the present invention, in step (2), the temperature of the immersion is preferably 60 - 80 °C, more preferably 65 - 75 °C, and even more preferably 68 - 72 °C.

[0038] In the present invention, in step (2), the time of the immersion is preferably 1 - 4 h, more preferably 1.5 - 3.5 h, and even more preferably 2 - 3 h.

[0039] In the present invention, after the immersion in step (2), drying and calcining are carried out to obtain the sintered flue gas CO catalyst. The temperature of the drying is preferably 110 - 140 °C, more preferably 115 - 135 °C, and even more preferably 120 - 130 °C. The time of the drying is preferably 12 - 24 h, more preferably 16 - 20 h, and even more preferably 17 - 19 h.

[0040] In the present invention, the calcination temperature in step (2) is preferably 280 to 350 °C, more preferably 300 to 330 °C, and even more preferably 310 to 320 °C.

[0041] In the present invention, the calcination time in step (2) is preferably 3 to 6 h, more preferably 3.5 to 5.5 h, and even more preferably 4 to 5 h.

[0042] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0043] Example 1

[0044] Dissolve 0.01 g of PtCl4, 0.05 g of Ce(NO3)3, and 0.5 g of FeCl3 in 100 mL of water to obtain a precursor solution;

[0045] Immerse 15 g of TiO2 and 10 g of carbon nanotubes in the precursor solution at a temperature of 60 °C. After immersion for 1 h, take them out, dry them at 110 °C for 12 h, and then calcine them at 280 °C for 3 h to obtain the sintering flue gas CO catalyst.

[0046] Example 2

[0047] Dissolve 0.1 g of PtCl4, 0.15 g of Ce(NO3)3, and 1.5 g of FeCl3 in 300 mL of water to obtain a precursor solution;

[0048] Immerse 150 g of TiO2 and 30 g of carbon nanotubes in the precursor solution at a temperature of 80 °C. After immersion for 4 h, take them out, dry them at 120 °C for 16 h, and then calcine them at 350 °C for 6 h to obtain the sintering flue gas CO catalyst.

[0049] Example 3

[0050] Dissolve 0.08 g of PtCl4, 0.07 g of Ce(NO3)3, and 0.7 g of FeCl3 in 100 mL of water to obtain a precursor solution;

[0051] Immerse 60 g of TiO2 and 24 g of carbon nanotubes in the precursor solution at a temperature of 65 °C. After immersion for 2 h, take them out, dry them at 110 °C for 24 h, and then calcine them at 320 °C for 4 h to obtain the sintering flue gas CO catalyst.

[0052] Performance test

[0053] The catalysts prepared in Examples 1 to 3 were used to remove CO in the sintering flue gas. The measurement time was 1 h and the catalytic temperature was 280 °C. The catalytic activities of the catalysts are shown in Table 1.

[0054] The components of the sintering flue gas include 9000 ppm of CO, 16 vol.% of O2, 550 ppm of NO, 200 ppm of SO2, and the rest is N2.

[0055] Table 1 Catalytic activity table of the catalysts obtained in Examples 1 - 3 in the presence of SO2

[0056] Example CO removal rate (%) Example 1 89.48％ Example 2 90.25％ Example 3 90.54％

[0057] Examples 1 - 3 were tested in the sintering flue gas components without SO2, and the experimental conditions were the same as above. The results are shown in Table 2.

[0058] Table 2 Catalytic activity table of the catalysts obtained in Examples 1 - 3 in the absence of SO2

[0059] Example CO removal rate (%) Example 1 97.62％ Example 2 98.21％ Example 3 98.56％

[0060] It can be seen from Tables 1 and 2 that for the sintering flue gas catalyst provided by the present invention, when there is no SO2, the CO removal rate is as high as 98.56%. When there is SO2, the removal rate only decreases by about 10%, showing excellent anti - poisoning performance.

[0061] As can be known from the above examples, the present invention provides a sintering flue gas CO catalyst with the structural formula of Pt - Ce - Fe3O4 / TiO2 - CNT, which is prepared from raw materials containing the following mass fractions: 0.01 - 0.1 part of PtCl4, 0.05 - 0.15 part of Ce(NO3)3, 0.5 - 1.5 parts of FeCl3, 15 - 150 parts of TiO2, and 10 - 30 parts of carbon nanotubes. After testing, for the sintering flue gas catalyst provided by the present invention, when there is no SO2, the CO removal rate is as high as 98.56%. When there is SO2, the removal rate only decreases by about 10%, showing excellent anti - poisoning performance.

[0062] The above - mentioned is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. Application of a catalyst in removing CO from sintering flue gas, characterized in that, The catalyst is prepared from raw materials comprising the following parts by mass: 0.01 - 0.1 part of PtCl4, 0.05 - 0.15 part of Ce(NO3)3, 0.5 - 1.5 parts of FeCl3, 15 - 150 parts of TiO2, 10 - 30 parts of carbon nanotubes; The preparation method of the catalyst comprises the following steps: (1) Dissolve PtCl4, Ce(NO3)3 and FeCl3 in water to obtain a precursor solution; (2) Immerse TiO2 and carbon nanotubes in the precursor solution, take them out and calcine to obtain the catalyst; The temperature of the immersion in step (2) is 60 - 80 °C; The time of the immersion in step (2) is 1 - 4 h; The components of the sintering flue gas include CO, O2, NO, SO2 and N2.

2. Use of the catalyst according to claim 1 in removing CO from sintering flue gas, characterized in that, The mass - volume ratio of PtCl4 to water in step (1) is 0.01 - 0.1 g: 80 - 400 mL.

3. Use of the catalyst according to claim 1 for removing CO from sintering flue gas, characterized in that, The temperature of the calcination in step (2) is 280 - 350 °C.

4. Use of the catalyst according to claim 3 for removing CO in sintering flue gas, characterized in that, The time of the calcination in step (2) is 3 - 6 h.