CN116393137A - Catalyst for high-humidity sintering flue gas and preparation method and application thereof - Google Patents

Abstract

The invention provides a catalyst for high-humidity sintering flue gas and its preparation method and application. The catalyst uses mullite honeycomb ceramics as a carrier, and the carrier is loaded with catalytic active components copper oxide and cerium oxide. The preparation method of the catalyst comprises the following steps: carrier pretreatment, configuring active component solution, impregnating mullite honeycomb ceramics, and drying and roasting. The catalyst for high-humidity sintering flue gas is applied to the selective oxidation and removal of CO in the sintering flue gas. The volume content of water vapor in the sintering flue gas is 8vol%~20vol%, and the volume content of CO is 0.3vol%~1.2vol%. The present invention realizes efficient and stable removal of CO in flue gas under high humidity and low CO conditions. Experiments prove that the catalyst of the present invention can still maintain a relatively high and stable CO conversion rate under the condition of 8vol%~20vol% water content , The CO conversion rate at 125°C is not lower than 60%, the CO conversion rate at 150°C is not lower than 71%, and the CO conversion rate at 175°C is not lower than 94%.

Description

Catalyst for high-humidity sintering flue gas and its preparation method and application

technical field

The invention relates to the technical field of sintering flue gas treatment, in particular to a catalyst for high-humidity sintering flue gas and its preparation method and application.

Background technique

The air pollutants in the iron and steel industry mainly come from the sintering/pelletizing process. Each ton of sinter produces about 4000m ³ ~8000m ^{3 of} flue gas, and the sintering flue gas usually contains 100mg/Nm ³ ~400mg/Nm ³ of NO, 400mg /Nm ³ ~2000mg/Nm ³ of SO ₂ , 8vol%~20vol% of water vapor, 14vol%~18vol% of O ₂ and 0.3vol%~1.2vol% of CO.

In 2019, five ministries including the Ministry of Ecology and Environment, the Development and Reform Commission, the Ministry of Industry and Information Technology, the Ministry of Finance, and the Ministry of Transport jointly issued the "Opinions on Promoting the Implementation of Ultra-Low Emissions in the Iron and Steel Industry". The emissions of dust, SO ₂ , and NO _x in the air have been greatly reduced, respectively, dust is less than 10 mg/m ³ , O ₂ is less than 35 mg/m ³ , and NO _x is less than 50 mg/m ³ , but the flue gas The problem of CO emissions has gradually emerged. The CO content in steel sintering flue gas can be as high as 6000~10000 mg/m ³ . The concentration of CO in some areas where iron and steel enterprises are concentrated exceeds 30-50% of the first-level air quality standard, becoming the main air pollutant in some areas. Environmental protection departments in Anyang, Handan, Changzhou, Tangshan and other places have clearly requested to control the emission of CO in sintering flue gas.

At present, the sintering plants of iron and steel enterprises generally control CO emissions from low-carbon sintering and related technologies that regulate the sintering combustion process. Coupled with the complexity of the sintering process, it is impossible to achieve a substantial reduction of CO emissions. Flue gas treatment is a means, but currently there are few mature treatment processes for reducing CO emissions from sintering waste gas. Among many methods, catalytic oxidation is considered to be the most effective because of its low operating temperature, high combustion efficiency and environmental friendliness. a way.

At present, the main active components of the common CO catalytic oxidation catalysts on the market are mostly precious metals such as platinum Pt, rhodium Rh, palladium Pt, etc., which are expensive, and the process is mostly a coating process. The active components are coated on the surface of cordierite honeycomb carrier or metal carrier. , forming a thin layer of active layer, because the composition of the flue gas is complex and contains a large number of solid particles of different sizes, if the CO catalytic oxidation equipment is placed before the SCR equipment, the wear of the flue gas on the surface of the CO catalytic oxidation catalyst is more obvious , the catalytic activity of the CO catalytic oxidation catalyst prepared by the coating process is significantly reduced after the surface active layer is worn away after being used for a period of time. Moreover, the particulate catalyst used in traditional flue gas purification has problems such as large pressure resistance, easy heat accumulation, and insufficient strength leading to pulverization. Therefore, it is of great significance to develop a monolithic catalyst for the catalytic oxidation of flue gas CO with low price and long catalytic life.

At present, commonly used CO catalysts can be mainly divided into two categories: noble metal catalysts and non-noble metal catalysts. Most of the active components of traditional noble metal catalysts are Pd, Pt, Rh, Au, etc. These noble metal catalysts have high catalytic efficiency and good water resistance, and are more stable in the reaction process, but they are expensive and not suitable for flue gas treatment. Commonly used non-noble metal catalysts, such as copper manganese oxide (MnO _x -CuO _y ), have better catalytic effects in dry flue gas. However, in the case of high water content in flue gas, the catalytic efficiency of such catalysts will be greatly reduced. Therefore, it is necessary to develop a catalyst with long-term and stable catalytic efficiency for flue gas with high water content and low CO content.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the object of the present invention is to provide a catalyst for high-humidity sintering flue gas and its preparation method and application.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A catalyst for high-humidity sintered flue gas, the catalyst uses mullite honeycomb ceramics as a carrier, and the carrier is loaded with catalytic active components copper oxide and cerium oxide.

The mullite honeycomb ceramic is a zirconium-containing mullite honeycomb ceramic with a zirconium content of 0.5%-1.2%, and the porosity of the mullite honeycomb ceramic is 60% and the specific surface area is 1290m ² /m ³ .

The inner holes of the mullite honeycomb ceramics are square holes with a diameter of 2 mm and a wall thickness between the holes of 1.1 mm.

The preparation method of the catalyst for high-humidity sintering flue gas is characterized in that it comprises the following steps:

S1. Carrier pretreatment

Wash the mullite with deionized water for 3~5 times, put the washed mullite into the muffle furnace for roasting, first raise the temperature to 120°C~130°C, keep it for 1h~1.5h, and then raise the temperature to 350°C~600°C , keep for 1h~2.5h, and cool down to room temperature with the furnace;

S2, configure the active component solution

Use Cu(NO ₃ ) ₂ 6H ₂ O and deionized water to prepare copper ion aqueous solution with a concentration of 1mol/L~3mol/L, and use Ce(NO ₃ ) ₃ 6H ₂ O and deionized water to prepare a concentration of 1mol /L~6mol/L cerium ion aqueous solution; then the copper ion aqueous solution and the cerium ion aqueous solution are mixed in proportion to form an active component solution, and the mixing volume ratio of the copper ion aqueous solution and the cerium ion aqueous solution is 1:7~1:1 ;

S3, impregnation of mullite honeycomb ceramics

Immerse the pretreated mullite honeycomb ceramics into the active component solution, stir and impregnate for 10 hours, then filter and take out the mullite honeycomb ceramics;

S4, drying and roasting

The impregnated honeycomb ceramic mullite is dried and calcined, and then cooled to room temperature to obtain a catalyst for high-humidity sintering flue gas.

In the step S2, the mixing volume ratio of the copper ion aqueous solution and the cerium ion aqueous solution is 1:3.

In the step S3, the mass volume ratio of the mullite honeycomb ceramics to the active component solution is 100g/L-1000g/L.

The specific steps of the step S4 are: heating the impregnated mullite honeycomb ceramics to 100°C~120°C under the protection of N2 or Ar atmosphere, keeping it for 2h~3h, then raising the temperature to 300°C~350°C, keeping it for 3h After ~4h, cool down to room temperature to obtain the catalyst for high-humidity sintering flue gas.

The calcination temperature is 350° C., and the calcination time is 4 hours.

The catalyst for high-humidity sintering flue gas is applied to the selective oxidation and removal of CO in sintering flue gas. The water vapor volume content in the sintering flue gas is 8vol%-20vol%, and the CO volume content is 0.3vol%-1.2vol%.

Owing to having adopted above-mentioned technical scheme, the technical progress that the present invention obtains is:

The invention provides a catalyst for high-humidity sintering flue gas and its preparation method and application, which realizes efficient and stable removal of CO in flue gas under high humidity and low CO. It is proved by experiments that the catalyst of the present invention can be used at 8vol%~ In the case of 20vol% water content, it still maintains a high and stable CO conversion rate. The CO conversion rate at 125°C is not lower than 60%, the CO conversion rate at 150°C is not lower than 71%, and the CO conversion rate at 175°C The conversion rate is not less than 94%. The catalyst of the invention has simple preparation process, low cost of raw materials, high catalytic life and wide application prospect in the end treatment of sintering flue gas.

In the present invention, the main active components Cu and Ce are loaded on the pretreated mullite honeycomb ceramics in the form of oxides by an impregnation method to obtain a monolithic catalyst loaded with copper oxides and cerium oxides, and then After drying, calcination, and cooling, it has a higher specific surface area and mass transfer rate, which further improves the catalytic activity for CO. Compared with the coating process catalyst, the process is simple and mature, and the distribution of active components in the pores of the carrier is more uniform, which is more suitable for industrial applications.

The mullite honeycomb ceramic used in the present invention is used as a catalyst carrier, has a regular skeleton structure and a relatively large specific surface area, and can uniformly load active components on the skeleton surface to ensure uniform and efficient catalytic effects of each part. The present invention further limits the inner pores of mullite honeycomb ceramics to be square pores, and accurately limits the pore diameter, wall thickness between pores, and porosity, which can ensure that the carrier has a larger specific surface area, increase the loading capacity of active components, and improve CO catalytic efficiency.

The present invention also limits the zirconium content in the mullite honeycomb ceramics to be 0.5%-1.2%. Moderate zirconium content has two important functions in the carrier. One is that when zirconia transforms from the tetragonal phase to the monoclinic phase, the volume will change accordingly, and at the same time, microcracks smaller than the critical size will be formed around the transformed particles. Microcracks and residual stress can toughen and strengthen honeycomb mullite ceramics, making its toughness doubled and its brittleness reduced; the other is that it is often used as a carrier component for supporting copper in CO oxidation reactions. The reason is that zirconium The work function of zirconium is higher than that of copper, which makes it easy for zirconium to donate electrons, so that metallic copper has a tendency to be positively charged (its outer electrons are affected), which reduces the reduction temperature of Cu ²⁺ and is easy to be reduced, thereby increasing the copper Adsorption capacity for CO.

The present invention uses relatively cheap Cu and Ce as the active components of the catalyst, which significantly reduces the production cost of the catalyst while ensuring the catalytic effect, and is beneficial to industrial promotion.

Description of drawings

Fig. 1 is the CO conversion rate curve of Example 3 at different temperatures;

Fig. 2 is the CO conversion rate curve of Example 3 under different water vapor contents;

Figure 3 is the 720h stability curve of CO catalytic efficiency.

Detailed ways

The present invention will be described in detail below in conjunction with examples.

In the following examples, the mullite honeycomb ceramics used are zirconium-containing mullite honeycomb ceramics with a zirconium content of 1.0%, the porosity of the mullite honeycomb ceramics is 60%, and the specific surface area is 1290m ² /m ³ , and the inner hole of the mullite honeycomb ceramic is a square hole, the hole diameter is 2mm, and the wall thickness between the holes is 1.1mm.

Example 1

The invention discloses a catalyst for high-humidity sintered flue gas, which uses mullite honeycomb ceramics as a carrier, and the carrier is loaded with catalytic active components copper oxide and cerium oxide. The porosity of the mullite honeycomb ceramic carrier is 60%.

The catalyst for high-humidity sintering flue gas is prepared by the following steps:

S1. Carrier pretreatment

Wash the mullite 3 times with deionized water, put the washed mullite into the muffle furnace for roasting, first raise the temperature to 130°C, keep it for 1.5h, then raise the temperature to 600°C, keep it for 2.5h; cool to room temperature with the furnace ;

S2, configure the active component solution

Use Cu(NO ₃ ) ₂ 6H ₂ O and deionized water to prepare copper ion aqueous solution with a concentration of 1mol/L, and use Ce(NO ₃ ) ₃ 6H ₂ O and deionized water to prepare cerium with a concentration of 1mol/L Ion aqueous solution; then the copper ion aqueous solution and the cerium ion aqueous solution are mixed into an active component solution in a volume ratio of 1:1, and the ratio of copper to cerium in the active component solution is 1:1;

S3, impregnation of mullite honeycomb ceramics

Add the pretreated mullite honeycomb ceramics in step 1 to the active component solution, the addition amount is 1000g/L; after stirring and impregnating for 10h, filter and take out the mullite honeycomb ceramics;

S4, drying and roasting

The impregnated honeycomb ceramic mullite is first heated to 100°C under the protection of nitrogen atmosphere, kept for 3 hours, then heated to 300°C, kept for 4 hours, cooled to room temperature, and the catalyst for high-humidity sintering flue gas is obtained.

Example 2

The invention discloses a catalyst for high-humidity sintered flue gas, which uses mullite honeycomb ceramics as a carrier, and the carrier is loaded with catalytic active components copper oxide and cerium oxide. The porosity of the mullite honeycomb ceramic carrier is 60%.

The catalyst for high-humidity sintering flue gas is prepared by the following steps:

S1. Carrier pretreatment

Wash the mullite 3 times with deionized water, put the washed mullite into the muffle furnace for roasting, first raise the temperature to 130°C, keep it for 1.5h, then raise the temperature to 600°C, keep it for 2.5h; cool to room temperature with the furnace ; S2, configure the active component solution

Use Cu(NO ₃ ) ₂ 6H ₂ O and deionized water to prepare a copper ion aqueous solution with a concentration of 1mol/L, and use Ce(NO ₃ ) ₃ 6H ₂ O and deionized water to prepare a cerium solution with a concentration of 2mol/L Ion aqueous solution; then mix the copper ion aqueous solution and the cerium ion aqueous solution at a volume ratio of 1:1 to form an active component solution, and the ratio of copper to cerium in the active component solution is 1:2;

S3, impregnation of mullite honeycomb ceramics

Add the pretreated mullite honeycomb ceramics in step 1 to the active component solution, the addition amount is 1000g/L; after stirring and impregnating for 10h, filter and take out the mullite honeycomb ceramics;

S4, drying and roasting

The impregnated honeycomb ceramic mullite is first heated to 100°C under the protection of nitrogen atmosphere, kept for 3 hours, then heated to 300°C, kept for 4 hours, cooled to room temperature, and the catalyst for high-humidity sintering flue gas is obtained.

Example 3

The invention discloses a catalyst for high-humidity sintered flue gas, which uses mullite honeycomb ceramics as a carrier, and the carrier is loaded with catalytic active components copper oxide and cerium oxide. The porosity of the mullite honeycomb ceramic carrier is 60%.

The catalyst for high-humidity sintering flue gas is prepared by the following steps:

S1. Carrier pretreatment

Wash the mullite 3 times with deionized water, put the washed mullite into the muffle furnace for roasting, first raise the temperature to 130°C, keep it for 1.5h, then raise the temperature to 600°C, keep it for 2.5h; cool to room temperature with the furnace ; S2, configure the active component solution

Use Cu(NO ₃ ) ₂ ·6H ₂ O and deionized water to prepare copper ion aqueous solution with a concentration of 2 mol/L, and use Ce(NO ₃ ) ₃ ·6H ₂ O and deionized water to prepare cerium with a concentration of 6 mol/L Ion aqueous solution; then mix the copper ion aqueous solution and the cerium ion aqueous solution at a volume ratio of 1:1 to form an active component solution, and the ratio of copper to cerium in the active component solution is 1:3;

S3, impregnation of mullite honeycomb ceramics

Take the pretreated mullite honeycomb ceramics in step 1 and add them to the active component solution, the addition amount is 1000g/L; after stirring and impregnating for 10h, filter and take out the mullite honeycomb ceramics;

S4, drying and roasting

The impregnated honeycomb ceramic mullite is first heated to 100°C under the protection of nitrogen atmosphere, kept for 3h, then raised to 350°C, kept for 4h, cooled to room temperature, and the catalyst for high-humidity sintering flue gas is obtained.

Example 4

The invention discloses a catalyst for high-humidity sintered flue gas, which uses mullite honeycomb ceramics as a carrier, and the carrier is loaded with catalytic active components copper oxide and cerium oxide. The porosity of the mullite honeycomb ceramic carrier is 60%.

The catalyst for high-humidity sintering flue gas is prepared by the following steps:

S1. Carrier pretreatment

Wash the mullite 3 times with deionized water, put the washed mullite into the muffle furnace for roasting, first raise the temperature to 130°C, keep it for 1.5h, then raise the temperature to 600°C, keep it for 2.5h; cool to room temperature with the furnace ; S2, configure the active component solution

Use Cu(NO ₃ ) ₂ 6H ₂ O and deionized water to prepare a copper ion aqueous solution with a concentration of 1mol/L, and use Ce(NO ₃ ) ₃ 6H ₂ O and deionized water to prepare a cerium solution with a concentration of 3mol/L Ion aqueous solution; then mix the copper ion aqueous solution and the cerium ion aqueous solution at a volume ratio of 1:1 to form an active component solution, and the ratio of copper to cerium in the active component solution is 1:3;

S3, impregnation of mullite honeycomb ceramics

Take the pretreated mullite honeycomb ceramics in step 1 and add them to the active component solution, the addition amount is 1000g/L; after stirring and impregnating for 10h, filter and take out the mullite honeycomb ceramics;

S4, drying and roasting

The impregnated honeycomb ceramic mullite is first heated to 100°C under the protection of nitrogen atmosphere, kept for 3 hours, then heated to 300°C, kept for 4 hours, cooled to room temperature, and the catalyst for high-humidity sintering flue gas is obtained.

The beneficial effects of the present invention will be described below using comparative examples.

Comparative example 1

This comparative example is a comparative example of Example 3. The preparation steps and parameter control are basically the same as those of Example 3. The difference from Example 3 is that in step S2, the concentration of the copper ion aqueous solution prepared is 0.5mol/L, and the cerium ion The concentration of the aqueous solution is 1.5mol/L; the mixing ratio of the copper ion aqueous solution and the cerium ion aqueous solution is 1:1, and the ratio of copper to cerium is 1:3.

Comparative example 2

This comparative example is a comparative example of Example 3, and the preparation steps and parameter control are basically the same as those of Example 1. The difference from Example 1 is that in step S4, the drying and roasting process is carried out under an air atmosphere.

Comparative example 3

This comparative example is a comparative example of Example 3, which is used to compare the influence of the specification of mullite honeycomb ceramics on the catalytic effect.

The preparation steps and parameter control of this comparative example are basically the same as in Example 3, the difference from Example 3 is that the mullite honeycomb ceramics used have a pore diameter of 8 mm, a wall thickness of 1 mm, and a porosity of 70%.

Comparative example 4

This comparative example is a comparative example of an existing catalyst product, which is prepared by the method disclosed in Chinese patent ZL202111214834.9 "A denitrification catalyst for CO-SCR flue gas denitrification and its preparation method".

The specific preparation method is:

(1) Soak the mullite honeycomb carrier in water for 24 hours, then dry and weigh at 80°C for use;

(2) Add 241 .6g of Cu(NO ₃ ) ₂ ·3H ₂ O and 2896.25g of Ce(NO ₃ ) ₂ ·6H ₂ O into 2000g of deionized water, stir until dissolved to obtain a metal salt solution, and then Add 1mol/L sodium hydroxide solution to adjust the pH to 10-11, stir for 4 hours and let it stand for 24 hours, then use pure water to filter to neutral, then use ethanol to filter for 30 minutes, and then dry the filtered solid at 80°C dry, then pulverized and sieved to 100 mesh catalyst precursor for use;

(3) Take 4333g of pure water in the interlayer stirring pot, heat the oil bath to 70°C and turn on the stirring, then take 253.97g of polyethylene glycol (molar mass is 6000), 253.97g sodium carboxymethyl cellulose (viscosity is 600-3000), 317.46g acidic silica sol (mass fraction is 30%), and 31.75g Tween-20 are mixed. During the addition process, each substance will be dissolved until the substance is dissolved before adding the next substance. Finally, 1 kg of the catalyst precursor was added, and stirred at a constant temperature for 4 hours to obtain a slurry. The slurry concentration was 30%, and the pH value was 4.1.

(4) Put the mullite honeycomb carrier into a 20cm*20cm*20cm mold, then pour the prepared slurry into the mold box and soak for 2 hours;

(5) Dry the impregnated and coated mullite honeycomb carrier at 80°C for 24h, then raise the temperature to 550°C in a muffle furnace at a rate of 10°C/min, and calcinate for 4h to obtain the mullite honeycomb monolithic CO Low temperature denitrification catalyst.

The finished catalysts prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to simulated sintering flue gas CO catalytic oxidation experiments. The inlet flue gas included: 1vol% CO, 16vol% O ₂ , 8vol% water vapor, 0.02vol% %NO, 7vol% CO ₂ , the carrier gas is N ₂ .

The specific process of the experiment is:

The activity experiment was carried out on a self-made catalyst test platform, and the CO conversion rate at three temperature points of 100°C, 175°C, and 250°C were measured with GHSV (gas space velocity per hour) = 6000h ^-1 flue gas. When the temperature of the reactor is stabilized to a certain temperature point, the simulated flue gas is introduced. After 30 minutes of reaction, the CO concentration in the gas before and after the reaction is measured using a flue gas analyzer. The continuous measurement time of each temperature point is 10 minutes, and the average value is taken. , and the CO conversion was calculated according to the following formula.

CO conversion rate = [(CO _in - CO _out )/CO _in ] × 100%

It should be noted that the simulated sintering flue gas CO catalytic oxidation experiment was carried out in a fixed-bed quartz reactor with temperature programming control. for analysis.

The reaction conditions and activity results of Examples 1 to 4 are shown in Table 1, and the reaction conditions and activity results of Comparative Examples 1 to 4 are shown in Table 2.

Table 1 CO conversion of catalysts with different copper-cerium ratios and impregnating solution concentrations

It can be seen from Table 1 that when the flue gas temperature exceeds 250 °C, the catalytic conversion rate of CO can reach 100% for catalysts with different copper-cerium ratios; but when the flue gas temperature decreases, the CO conversion rate decreases to varying degrees. Among them, at 175°C in Example 1, the CO conversion rate decreased to below 85%, while in Examples 2 to 4 at 175°C, the CO conversion rate remained above 90%, wherein the ratio of copper to cerium was 1:3 The CO conversion rate of Example 3 and Example 4 can reach more than 98%. When the flue gas temperature is 100°C, the CO conversion rates of Example 3 and Example 4 are still significantly higher than those of Example 1 and Example 2. Through the comparison of the above data, it can be determined that the ratio of copper to cerium in the preparation process has a great influence on the activity of the finished catalyst, and the optimal ratio of copper to cerium is 1:3, which has the best CO removal performance. The catalyst preparation of the subsequent comparative examples is based on the examples 3 for reference.

The difference between Example 3 and Example 4 is that the concentration of the impregnation solution in Example 3 is doubled, which also slightly increases the CO removal rate of the finished catalyst.

Table 2 CO conversion of catalysts prepared with different parameters

From the CO conversion rate data of Comparative Example 1, it can be seen that even if the copper-cerium ratio is within a reasonable range, the concentration of the copper ion aqueous solution and the cerium ion aqueous solution is too low, which will lead to a low content of active components in the catalyst and a low CO removal efficiency. Significantly decreased.

From the CO conversion rate data of Comparative Example 2, it can be seen that the control of the atmosphere during the calcination process of the catalyst also significantly affects the catalytic effect. Roasting under the _N2 atmosphere can make the active material crystals evenly distributed on the surface of the carrier and slow down the crystal growth. Therefore, the occurrence of sintering and agglomeration of the active components on the surface of the catalyst is reduced, and the fine grains are more firmly bonded to the carrier and are not easy to fall off, which can significantly improve the catalytic effect of the catalyst.

The present invention limits the specifications of the mullite honeycomb ceramics to be 2 mm in diameter, square holes, and a porosity of 60%. From the CO conversion rate data of Comparative Example 3, it can be seen that after the carrier pore size increases, its specific surface area is reduced, and the contact sites between CO and catalyst surface active substances are reduced, which is not conducive to the removal of CO; similarly, the porosity The reduction of the carrier will also lead to a decrease in the specific surface area of the carrier.

Comparative example 4 is a copper cerium mullite honeycomb catalyst prepared by coating method, its catalytic effect is slightly better than the method provided by this patent, but its preparation process is not relatively complicated compared with this patent, and the catalyst needs to be prepared by co-precipitation method first The powder is then formulated into a slurry, and a binder is also used. The steps are relatively cumbersome, which is not conducive to industrial preparation and application.

For a more detailed understanding of the catalytic performance of the catalyst of the present invention, preferred embodiment 3 is the subject of follow-up experiments. The activity and water resistance of the catalyst of embodiment 3 are tested in the laboratory, and then the stability test is carried out at the enterprise site.

Attached Figure 1 is the change curve of CO conversion rate at different temperatures in Example 3. It can be seen that Example 3 can reach nearly 50% CO conversion rate at 100 ° C; the temperature range of sintering flue gas is 100 ° C ~ 130 ° C, without heating , can achieve a CO removal rate of about 60%; at 175°C~250°C, the CO catalytic rate can reach 100%, and it is completely possible to achieve a CO emission of less than 2000mg/m ³ , which is currently the most stringent standard for CO emission limits of 4000mg/m3 half of ^m3 .

Accompanying drawing 2 is the influence curve of water vapor content on CO conversion rate. It can be seen from Figure 2 that with the increase of water vapor content, the overall CO conversion rate showed a downward trend, but it did not cause a significant drop in the CO conversion rate of the catalyst, and with the increase of the reaction temperature, the adverse effect of water vapor on the CO conversion rate would be significantly weakened. When the sintering flue gas temperature is 125°C, as the water vapor content increases from 0 to 20vol%, the CO conversion rate decreases from 73% to 60%, a drop of about 13%; when the sintering flue gas temperature is 150°C, as the water vapor content increases from 0 When the sintering flue gas temperature is 175°C, the CO conversion rate drops from 100% to 94% as the water vapor content increases from 0 to 20vol%. down about 6%.

Approximate experimental conditions (reaction temperature 180°C, 240°C, water vapor content 0-30%) were used in the master's thesis "Research on Optimum Treatment of Sintering Flue Gas Low Concentration CO Removal" published by Cheng Yi and Zhou Hao. Pt-coated honeycomb metal/Ce-modified Fe ₂ O ₃ catalysts in the range of 0-20% water vapor content, the CO conversion rate decreased by nearly 20%, and with the increase of temperature, the catalytic efficiency of the catalyst did not change. Significant change, higher than the 6% decrease in CO conversion rate in the range of 175°C and 0-20% water vapor content in Example 3 of the present invention, and with the increase of temperature, the CO conversion rate increased significantly; thus proving that the Example 3 of the present invention The catalyst has very good water resistance.

In order to verify the practicability of Example 3, the on-site stability test of sintering flue gas was carried out, and the CO catalytic stability test of the catalyst of Example 3 was carried out by using the actual sintering flue gas after desulfurization and denitrification in a steel plant. The flue gas components are: 0.6%～0.7%CO, 12%～15%H ₂ O, 14%O ₂ , 4%CO ₂ , NO _x <10mg·Nm ³ , SO ₂ ≤5mg·Nm ³ , N ₂ ( residual gas), the inlet temperature of the reactor is 180°C, and the space velocity is 6000h ^-1 . Accompanying drawing 3 is the time-varying graph of the catalytic efficiency of the whole process. In the initial stage (0-60h), the catalytic efficiency of CO can be kept above 98%; then it shows a downward trend; after 360h, the catalytic efficiency tends to be stable and maintains at More than 86%, until the end of the 720h experiment.

Article "Comparison of Pt-coated Honeycomb Metal and Ce-modified Fe ₂ O ₃ Catalytic Performance of CO"("Journal of Engineering Science", Zhou Hao, Cheng Yi, Zhou Mingxi, Ni Yuguo et al., 2020, 42(1): 70-77 ), under the approximate sintering flue gas conditions (0.45%CO, 11.7%H ₂ O, 7077h ^–1 space velocity, 180℃ inlet temperature), the Pt-coated honeycomb metal/Ce modified Fe ₂ O ₃ The CO catalytic efficiencies obtained by the two catalysts were 63.9% and 34.9%, respectively, which were lower than the stable efficiency (above 86%) obtained by the present invention after 720 hours of catalysis.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (10)

1. A catalyst for high-humidity sintering flue gas, characterized in that: the catalyst uses mullite honeycomb ceramics as a carrier, and the catalytically active components copper oxide and cerium oxide are loaded on the carrier. 2. A catalyst for high-humidity sintering flue gas according to claim 1, characterized in that: the mullite honeycomb ceramics is a zirconium-containing mullite honeycomb ceramics with a zirconium content of 0.5% to 1.2%, and the mollite honeycomb ceramics The porosity of Laishi honeycomb ceramics is 60%. 3. A catalyst for high-humidity sintered flue gas according to claim 2, characterized in that: the inner holes of the mullite honeycomb ceramics are square holes with a diameter of 2 mm and a wall thickness between the holes of 1.1 mm. 4. according to the preparation method of the described high humidity sintering flue gas catalyst of claim 1～claim 3, it is characterized in that comprising the following steps: S1. Carrier pretreatment Wash the mullite with deionized water for 3~5 times, put the washed mullite into the muffle furnace for roasting, first raise the temperature to 120°C~130°C, keep it for 1h~1.5h, and then raise the temperature to 350°C~600°C , keep for 1h~2.5h, and cool down to room temperature with the furnace; S2, configure the active component solution Use Cu(NO ₃ ) ₂ 6H ₂ O and deionized water to prepare copper ion aqueous solution with a concentration of 1mol/L~3mol/L, and use Ce(NO ₃ ) ₃ 6H ₂ O and deionized water to prepare a concentration of 1mol /L~6mol/L cerium ion aqueous solution; then the copper ion aqueous solution and the cerium ion aqueous solution are mixed in proportion to form an active component solution, and the mixing volume ratio of the copper ion aqueous solution and the cerium ion aqueous solution is 1:7~1:1 ; S3, impregnation of mullite honeycomb ceramics Immerse the pretreated mullite honeycomb ceramics into the active component solution, stir and impregnate for 10 hours, then filter and take out the mullite honeycomb ceramics; S4, drying and roasting The impregnated honeycomb ceramic mullite is dried and calcined, and then cooled to room temperature to obtain a catalyst for high-humidity sintering flue gas. 5. The method for preparing a catalyst for high-humidity sintering flue gas according to claim 4, characterized in that: in the step S2, the mixing volume ratio of the copper ion aqueous solution and the cerium ion aqueous solution is 1:3. 6. The method for preparing a catalyst for high-humidity sintering flue gas according to claim 4, characterized in that: in the step S3, the mass volume ratio of the mullite honeycomb ceramics to the active component solution is 100g/L~1000g /L. 7. The preparation method of the catalyst for high-humidity sintering flue gas according to claim 4, characterized in that: the specific step of the step S4 is that the impregnated mullite honeycomb ceramics is under _N2 or Ar atmosphere protection First raise the temperature to 100°C~120°C, keep it for 2h~3h, then raise the temperature to 300°C~350°C, keep it for 3h~4h, and cool to room temperature to get the catalyst for high-humidity sintering flue gas. 8 . The method for preparing a catalyst for high-humidity sintering flue gas according to claim 7 , characterized in that: the calcination temperature is 350° C., and the calcination time is 4 hours. 9. The application of the catalyst for high-humidity sintering flue gas according to claim 1 to claim 3, characterized in that: the catalyst for high-humidity sintering flue gas is used for selective oxidation and removal of CO in sintering flue gas. 10. The application of the catalyst for high-humidity sintering flue gas according to claim 9, characterized in that: the water vapor volume content in the sintering flue gas is 8vol%~20vol%, and the CO volume content is 0.3vol%~1.2vol %.

Images