Preparation method of SCR (Selective Catalytic Reduction) denitration catalyst

Abstract

The invention discloses a preparation method of an SCR (Selective Catalytic Reduction) denitration catalyst, which specifically comprises the following steps: (1) cleaning, drying, crushing, sieving and carbonizing a biomass material to obtain biomass charcoal; and (2) uniformly mixing with ruthenium chloride trihydrate, adding water, stirring and dipping, drying, grinding and calcining to obtain the catalyst. According to the invention, the Ru is used as an active component, and the biomass charcoal with low price is simultaneously used as a carrier and a solid reducing agent to replace a traditional gas reducing agent to carry out solid-gas reaction, so that the resource utilization of biomass materials is realized, the use of traditional gas is saved, the industrial cost can be greatly reduced, and industrialization is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic reduction, and more particularly to a method for preparing a SCR denitration catalyst. Background Art

[0002] Nitrogen oxides (NO x ) refers to compounds composed of only two elements, nitrogen and oxygen, including a variety of compounds, such as nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O3), nitrous oxide (N2O4) and nitrous oxide pentoxide (N2O5), etc., mainly from fixed sources (power plants, steel mills, chemical plants, thermal power plants, industrial boilers, etc.) and mobile sources (exhaust emissions from motor vehicles and non-road machinery). The large-scale emission of nitrogen oxides has led to a series of environmental changes such as photochemical smog, acid rain, ozone depletion, ground ozone and greenhouse effect, which has caused great harm to human health and the natural environment. Therefore, the regulation of nitrogen oxides is becoming more and more stringent, and people are also using different technologies to reduce the emission of nitrogen oxides.

[0003] In the current denitrification process, the purpose of nitrogen oxide reduction technologies such as selective non-catalytic reduction technology (SNCR) and selective catalytic reduction technology (SCR) is to reduce nitrogen oxides to harmless nitrogen. Selective catalytic reduction to remove nitrogen oxides is the most widely used flue gas denitrification technology, with high denitrification efficiency, mature technology, and has been industrialized.

[0004] Currently, the reducing agents used in the selective catalytic reduction process are NH3, CO, H2, C n H x However, the reducing agent used in the conventional selective catalytic reduction denitrification technology is mostly gas.

[0005] Therefore, how to develop a solid reducing agent for selective catalytic reduction denitrification is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a method for preparing a SCR denitration catalyst to solve the deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for preparing an SCR denitration catalyst comprises the following steps:

[0009] (1) washing, drying, crushing, screening and carbonizing the biomass material to obtain biochar;

[0010] (2) Ruthenium chloride trihydrate and biochar are mixed evenly, water is added, stirred and impregnated, dried, ground, and calcined to obtain an SCR denitrification catalyst, which is named RuO2 / biochar.

[0011] Furthermore, in the above step (1), the biomass material is at least one of cotton straw, banana peel, corn straw, rape straw, wheat straw and soybean straw.

[0012] A further beneficial effect of adopting the above method is that the cost of the biomass material selected by the present invention is relatively low, which can effectively reduce industrial costs and thus achieve industrialization.

[0013] Furthermore, in the above step (1), the drying equipment is an oven at a temperature of 90°C.

[0014] Furthermore, in the above step (1), the crushing equipment is a high-speed multifunctional crusher, and the number of times is 3 times.

[0015] Furthermore, in the above step (1), the mesh size of the sieve is 100 meshes.

[0016] Furthermore, in the above step (1), the carbonization equipment is a muffle furnace, and the procedure is: first, the temperature is increased to 300°C at a rate of 5°C / min, carbonized for 3 hours, and then cooled to room temperature, and then the temperature is increased to 550-750°C at a rate of 10°C / min, and carbonized for 1 hour, and then cooled to room temperature.

[0017] Furthermore, in the above step (2), the mass ratio of ruthenium chloride trihydrate, biochar and water is 0.5:(10-50):(250-1000).

[0018] A further beneficial effect of the above is that Ru in the ruthenium chloride trihydrate selected in the present invention as a precious metal active substance has a significant catalytic effect in the removal of NO by SCR and has excellent low-temperature catalytic activity.

[0019] Furthermore, in the above step (2), the stirring and immersion rate is 400-600 r / min and the time is 10-12 h.

[0020] Furthermore, in the above step (2), the drying equipment is an oven, the temperature is 100-120° C., and the time is 10-12 hours.

[0021] Furthermore, in the above step (2), the calcination equipment is a tubular furnace, the atmosphere is N2, the temperature is 400-600°C, and the time is 6 hours.

[0022] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The present invention uses Ru as the active component and uses low-cost biochar as both a carrier and a solid reducing agent to replace the traditional gas reducing agent for solid-gas reaction, which not only realizes the resource utilization of biomass materials, but also saves the use of traditional gases, can greatly reduce industrial costs, and is conducive to industrialization.

[0024] 2. Aiming at the technical problems of the complex preparation process and poor low-temperature activity of Carbon-SCR denitration catalyst, the present invention adopts a simple impregnation method to prepare an SCR denitration catalyst with good low-temperature activity, and explores the effect of the active component loaded on biochar on the denitration performance. The preparation method of the present invention is simple, and the active component RuO2 is loaded on biochar. Biochar is not only a carrier but also a reducing agent, thereby improving the removal rate of NO in SCR at a lower temperature. It is applied to Carbon-SCR to show excellent denitration activity, and realizes the denitration process with solid as a reducing agent.

[0025] 3. Through testing, it was found that the biochar (SCR denitrification catalyst) loaded with RuO2 in the present invention greatly improved the conversion rate of NO. The conversion rate of NO can reach about 40% at 350°C and 100% at 400°C, and it has good stability, oxidation resistance and water resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM image of the biochar and SCR denitration catalyst prepared in Example 1;

[0027] Figure 2 The NO conversion rate of the biochar and SCR denitration catalyst prepared in Example 1 in flue gas. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] The preparation method of the SCR denitration catalyst specifically comprises the following steps:

[0031] (1) Cut the cotton straw into segments and wash them in deionized water. After washing, put them in an oven at 90°C for drying. After drying, put them in a high-speed multifunctional grinder for pulverization for 3 times, pass through a 100-mesh sieve, and then put them in a muffle furnace. First, heat them to 300°C at a rate of 5°C / min, carbonize them for 3h, and then cool them to room temperature. Then, heat them to 650°C at a rate of 10°C / min, continue carbonizing them for 1h, and then cool them to room temperature to obtain biochar.

[0032] (2) 0.5 g of ruthenium chloride trihydrate and 10 g of biochar were mixed evenly, 500 mL of deionized water was added, and the mixture was stirred and impregnated at a rate of 600 r / min for 12 h, then placed in an oven at 120 °C for 12 h, ground, and finally placed in a tubular furnace in a N2 atmosphere and calcined at 500 °C for 6 h to obtain an SCR denitrification catalyst.

[0033] Example 2

[0034] The preparation method of the SCR denitration catalyst specifically comprises the following steps:

[0035] (1) Cut the cotton straw into segments and wash them in deionized water. After washing, put them in an oven at 90°C for drying. After drying, put them in a high-speed multifunctional grinder for pulverization for 3 times, pass through a 100-mesh sieve, and then put them in a muffle furnace. First, heat them to 300°C at a rate of 5°C / min, carbonize them for 3h, and then cool them to room temperature. Then, heat them to 600°C at a rate of 10°C / min, continue carbonizing them for 1h, and then cool them to room temperature to obtain biochar.

[0036] (2) 0.5 g of ruthenium chloride trihydrate and 10 g of biochar were mixed evenly, 500 mL of deionized water was added, and the mixture was stirred and impregnated at a rate of 600 r / min for 12 h, then placed in an oven at 120 °C for 12 h, ground, and finally placed in a tubular furnace in a N2 atmosphere and calcined at 500 °C for 6 h to obtain an SCR denitrification catalyst.

[0037] Example 3

[0038] The preparation method of the SCR denitration catalyst specifically comprises the following steps:

[0039] (1) Cut the cotton straw into segments and wash them in deionized water. After washing, put them in an oven at 90°C for drying. After drying, put them in a high-speed multifunctional grinder for pulverization for 3 times, pass through a 100-mesh sieve, and then put them in a muffle furnace. First, heat them to 300°C at a rate of 5°C / min, carbonize them for 3h, and then cool them to room temperature. Then, heat them to 550°C at a rate of 10°C / min, continue carbonizing them for 1h, and then cool them to room temperature to obtain biochar.

[0040] (2) 0.5 g of ruthenium chloride trihydrate and 10 g of biochar were mixed evenly, 500 mL of deionized water was added, and the mixture was stirred and impregnated at a rate of 600 r / min for 12 h, then placed in an oven at 120 °C for 12 h, ground, and finally placed in a tubular furnace in a N2 atmosphere and calcined at 500 °C for 6 h to obtain an SCR denitrification catalyst.

[0041] Example 4

[0042] The preparation method of the SCR denitration catalyst specifically comprises the following steps:

[0043] (1) Cut the cotton straw into segments and wash them in deionized water. After washing, put them in an oven at 90°C for drying. After drying, put them in a high-speed multifunctional grinder for pulverization for 3 times, pass through a 100-mesh sieve, and then put them in a muffle furnace. First, heat them to 300°C at a rate of 5°C / min, carbonize them for 3h, and then cool them to room temperature. Then, heat them to 750°C at a rate of 10°C / min, continue carbonizing them for 1h, and then cool them to room temperature to obtain biochar.

[0044] (2) 0.5 g of ruthenium chloride trihydrate and 10 g of biochar were mixed evenly, 500 mL of deionized water was added, and the mixture was stirred and impregnated at a rate of 600 r / min for 12 h, then placed in an oven at 120 °C for 12 h, ground, and finally placed in a tubular furnace in a N2 atmosphere and calcined at 500 °C for 6 h to obtain an SCR denitrification catalyst.

[0045] Example 5

[0046] The preparation method of the SCR denitration catalyst specifically comprises the following steps:

[0047] (1) Cut the banana peel into segments and wash it in deionized water. After washing, put it in an oven at 90°C to dry it. After drying, put it in a high-speed multifunctional grinder to crush it 3 times, pass it through a 100-mesh sieve, and then put it in a muffle furnace. First, heat it to 300°C at a rate of 5°C / min, carbonize it for 3h, and then cool it to room temperature. Then, heat it to 650°C at a rate of 10°C / min, continue carbonizing it for 1h, and then cool it to room temperature to obtain biochar;

[0048] (2) 0.5 g of ruthenium chloride trihydrate and 10 g of biochar were mixed evenly, 500 mL of deionized water was added, and the mixture was stirred and impregnated at a rate of 4600 r / min for 12 h, then placed in an oven at 120 °C for 12 h, ground, and finally placed in a tubular furnace in a N2 atmosphere and calcined at 500 °C for 6 h to obtain an SCR denitrification catalyst.

[0049] Example 6

[0050] The preparation method of the SCR denitration catalyst specifically comprises the following steps:

[0051] (1) Cut corn stalks into segments and wash them in deionized water. After washing, put them in an oven at 90°C for drying. After drying, put them in a high-speed multifunctional grinder for pulverization for 3 times, pass through a 100-mesh sieve, and then put them in a muffle furnace. First, heat them to 300°C at a rate of 5°C / min, carbonize them for 3h, and then cool them to room temperature. Then, heat them to 650°C at a rate of 10°C / min, continue carbonizing them for 1h, and then cool them to room temperature to obtain biochar.

[0052] (2) 0.5 g of ruthenium chloride trihydrate and 10 g of biochar were mixed evenly, 500 mL of deionized water was added, and the mixture was stirred and impregnated at a rate of 600 r / min for 12 h, then placed in an oven at 120 °C for 12 h, ground, and finally placed in a tubular furnace in a N2 atmosphere and calcined at 500 °C for 6 h to obtain an SCR denitrification catalyst.

[0053] Performance Testing

[0054] 1. Take the biochar (BC) and SCR denitration catalyst (RuO2 / BC) prepared in Example 1 and characterize their morphology by SEM. The results are as follows: Figure 1 shown.

[0055] Depend on Figure 1 It can be seen that Figure 1 (a) is biochar, which has an irregular block shape; Figure 1 (b) is an SCR denitrification catalyst, and it can be seen that evenly dispersed RuO2 particles are loaded on the surface of biochar.

[0056] 2. The biochar and SCR denitration catalyst (RuO2 / biochar) prepared in Example 1 were respectively applied to the Carbon-SCR flue gas denitration experiment, and the denitration of the above two catalysts was tested using simulated flue gas.

[0057] The specific experimental method is: the above two catalysts are passed through a fixed bed reactor to detect the denitrification performance. The reactor is a stainless steel tube with an inner diameter of 10.0 mm. Before the experiment, quartz sand and quartz wool are placed in the reaction tube to ensure the contact between the powder catalyst and the thermocouple. The simulated flue gas composition is: 500ppm NO, N2 as the balance gas. The total flue gas flow rate is 100mL / min, of which the NO flow rate is 40mL / min and the N2 flow rate is 60mL / min. Reaction temperature: 50-500℃.

[0058] The concentration of NO at the reactor outlet was detected by infrared device; the calculation formula of NO conversion rate is: NO conversion =(NO in -NO out ) / NO in ×100%.

[0059] The results are as follows Figure 2 shown.

[0060] Depend on Figure 2 It can be seen that at 350°C, the NO conversion rate of biochar is about 25%, and the NO conversion rate of the SCR denitrification catalyst is about 40%; at 400°C, the NO conversion rate of biochar is about 40%, and the NO conversion rate of the SCR denitrification catalyst reaches 100%.

[0061] Through comparison, it was found that the NO conversion rate of biochar can be greatly improved after loading RuO2.

[0062] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a SCR denitration catalyst, characterized in that: The specific steps include: (1) washing, drying, crushing, screening and carbonizing the biomass material to obtain biochar; (2) Ruthenium chloride trihydrate and biochar are mixed evenly, water is added, stirred and impregnated, dried, ground, and calcined to obtain the SCR denitration catalyst.

2. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (1), the biomass material is at least one of cotton straw, banana peel, corn straw, rape straw, wheat straw and soybean straw.

3. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (1), the drying equipment is an oven at a temperature of 90°C.

4. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (1), the crushing equipment is a high-speed multifunctional crusher, and the number of times is 3 times.

5. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (1), the mesh size of the sieve is 100 meshes.

6. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (1), the carbonization equipment is a muffle furnace, and the procedure is: first, the temperature is raised to 300°C at a rate of 5°C / min, carbonized for 3 hours, and then cooled to room temperature; then, the temperature is raised to 550-750°C at a rate of 10°C / min, carbonized for 1 hour, and then cooled to room temperature.

7. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (2), the mass ratio of ruthenium chloride trihydrate, biochar and water is 0.5:(10-50):(250-1000).

8. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (2), the stirring and immersion is carried out at a rate of 400-600 r / min and for a time of 10-12 h.

9. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (2), the drying equipment is an oven, the temperature is 100-120° C., and the time is 10-12 hours.

10. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: In step (2), the calcination equipment is a tubular furnace, the atmosphere is N2, the temperature is 400-600°C, and the time is 6 hours.

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