KR101309305B1 - Method of producing catalyst for selective catalytic reduction using refuse derived fuel char - Google Patents

Abstract

The present invention relates to a method for producing a catalyst for selective catalytic reduction using RDF VII. The catalyst for selective catalytic reduction prepared by the production method may have a nitrogen oxide reduction efficiency of 40% or more.

Description

METHODS OF PRODUCING CATALYST FOR SELECTIVE CATALYTIC REDUCTION USING REFUSE DERIVED FUEL CHAR}

The present invention relates to a method for producing a catalyst for selective catalytic reduction using a solid waste fuel fuel. According to the present invention, a catalyst having a significant nitrogen oxide reduction efficiency can be produced.

Nitrogen oxide (NOx), generated when burning fossil fuels, acts as a cause of acid rain as well as the greenhouse effect (N ₂ O), and produces various oxidants such as O ₃ , HCHO, and PAN to remove secondary pollution and photochemical smog. Cause. In addition, by destroying the respiratory cells of the human body, causing respiratory diseases, hemolytic action and central nervous system disorders.

The techniques for reducing nitrogen oxides are largely i) selective catalytic reduction techniques using a catalyst and a reducing agent together, ii) selective non-catalytic reduction techniques using only a reducing agent without a catalyst, and iii) low-temperature combustion conditions controlling the furnace. It can be divided into Low-NOx burner technology. Among them, selective catalytic reduction technology is widely used because of its excellent removal efficiency, selectivity, and economics.

Catalysts used in Selective Catalytic Reduction (SCR) technology include metal oxides, zeolites, alkaline earth metals, and rare earths. TiO ₂ , WO ₃ , V ₂ O ₅ , and MnO ₃ are mainly used. do. In particular, the vanadium pentoxide-based catalyst is known to be very excellent among the catalysts.

Diphosphorus pentoxide vanadium-based catalyst are one useful for the removal of NOx present in the exhaust gas, the NOx-containing exhaust gas, and the SO ₂ is present, the SO ₃ generated by the oxidation of SO ₂ is NH reacts with the unreacted ammonia, ₄ Produces ammonia sulfate, such as HSO ₄ and (NH ₄ ) ₂ SO ₄ . Since the ammonia sulphate may be deposited on the surface of the catalyst, problems such as deterioration of the life of the catalyst, increase in the pressure of the catalytic reactor, increase in corrosion of the heater, and the like may occur. Therefore, the vanadium pentoxide-based catalyst shows optimum activity in a high temperature range of 300 to 400 ° C., thereby additional installation of a heating facility is inevitable, thereby increasing initial investment and operating costs.

In order to solve the above problems, in order to reduce the cost by using a catalyst having an optimum activity at a low temperature of less than 300 ℃ as SCR catalyst, without additional installation of a heating facility, a study on carbon selective catalytic reduction technology It's going on.

Carbon Selective Catalytic Reduction (CSCR) technology introduces an oxygen functional group on the surface by treating carbon bodies such as activated carbon, activated carbon fibers, carbon nanotubes, and carbon black. Nitrogen oxides can be removed at low temperatures by adsorption of nitrogen oxides. However, the carbon bodies used for the carbon selective catalytic reduction have a disadvantage that the price is expensive to apply to the CSCR process.

On the other hand, interest in energyization using waste resources such as solid fuel has recently increased.

Refuse Derived Fuel (RDF) refers to combustible wastes such as waste plastics, waste fibers, waste tires, waste paper, waste wood, oil, animal by-products, etc., among industrial wastes and general wastes. As a material produced through a chemical treatment process and a molding process, not only the RDF but also by-products such as char generated by combustion, gasification, and pyrolysis to energize the RDF can be used in the waste resource energy process. have.

Since RDF 저가 is a low-cost material, it is expected that the low cost carbon catalyst used in the CSCR process will not only reduce the costs associated with waste disposal but also increase the economics of the catalyst system for nitrogen oxides.

It is to provide a method for producing a catalyst for selective catalytic reduction having a significant nitrogen oxide reduction efficiency using RDF VII.

According to one aspect, there is disclosed a method of producing a catalyst for selective catalytic reduction comprising pyrolyzing RDF to produce RDF VII, and activating the RDF VII.

Activating the RDF VII may include water treatment, KOH or NaOH treatment, ammonia treatment, or KOH or NaOH and ammonia treatment.

Additionally, the method may further comprise manganeseing the RDF shock.

According to another aspect, disclosed is a catalyst for selective catalytic reduction produced by the process.

According to the above production method, a catalyst for selective catalytic reduction having a significant nitrogen oxide reduction efficiency of 40% or more can be prepared.

1 is a schematic diagram of a pyrolysis apparatus used in Example 1. FIG.
2 is a schematic diagram of an apparatus for activation used in Example 2. FIG.
3 shows an activation process according to the third embodiment.
4 is a schematic diagram of an apparatus for treating ammonia used in Example 4. FIG.
5 is a graph showing nitrogen oxide reduction efficiency according to Example 1. FIG.
6 is a graph showing nitrogen oxide reduction efficiency according to Examples 2 and 3. FIG.
7 is a graph showing nitrogen oxide reduction efficiency according to Example 4. FIG.
8 is a graph showing nitrogen oxide reduction efficiency according to Example 5. FIG.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" and the like are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is implemented, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.

Unless otherwise defined herein, all terms used, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings of the context of the related art, and should not be construed as ideally or excessively formal meanings.

It is to provide a method for producing a catalyst for selective catalytic reduction having a significant nitrogen oxide reduction efficiency using RDF VII.

As used herein, the term "Refuse Derived Fuel" (RDF) refers to waste solid fuel, which includes four components of water, volatiles, fixed carbon and ash, and the elements C, H, O, N, and S It may include.

In general, the lower the content of water and the higher the content of volatile matter and fixed carbon in the four components, the higher the production energy required to generate the ,, the higher the production yield.

Among the elements, the higher the content of O can increase the oxygen functional group such as OH, C = O, CO on the surface of the 경우 when physical activation and chemical activation, it is possible to improve the efficiency of nitrogen oxides. In addition, the smaller the content of N and S, the less pollutants such as NOx, SOx and the like that can be released when pyrolysis of P may be emitted.

As used herein, the term “nitrogen oxide (NOx)” refers to a compound produced by combining nitrogen with oxygen and nitrogen contained in a fixed source such as an incinerator, a power plant, and a mobile source such as a car or a ship. it means.

The nitrogen oxide is N ₂ 0 (Nitrous Oxide), NO (Nitric Oxide), N ₂ O ₂ (Dinitrogen Dioxide), M ₂ O ₃ (Dinitrogen Trioxide), NO ₂ (Nitrogen Dioxide), N ₂ O ₄ (Dinitrogen Tetroxide ), N ₂ O ₅ (Dinitrogen Pentoxide).

As used herein, the term "Selective Catalytic Reduction (SCR)" means ammonia (NH ₃ ), urea (Urea), hydrocarbons (CO), etc. as a reducing agent and nitrogen oxides to the body harmless gas nitrogen and It means a method of decomposition into water vapor. When ammonia is used as the reducing agent in the SCR, the nitrogen oxides can be removed as in the formula:

4NO + 4NH ₃ + O ₂ ? 4N ₂ + 6H ₂ O

2NO ₂ + 4NH ₃ + O ₂ → 3N ₂ + 6H ₂ O

6NO + 4NH ₃ → 5N ₂ + 6H ₂ O

6NO ₂ + 8NH ₃ → 7N ₂ + 12H ₂ O

According to one embodiment, there is provided a method for producing a catalyst for selective catalytic reduction comprising pyrolyzing RDF to produce RDF VII, and activating the RDF VII. Additionally, the method may further comprise manganeseing the RDF shock.

RDF To By pyrolysis RDF 촤  Steps to generate

The pyrolysis means that raw materials are heated under an oxygen-free state such as gases such as H ₂ , CH ₄ , CO, CO ₂ , NH ₃ , H ₂ S, HCN, acetic acid, acetone, methanol, oil, tar, and essential oils. Refers to a process of decomposition into a liquid and a char such as an inert material.

In this embodiment, the pyrolysis of the RDF may be performed for about 1 hour to about 3 hours at a temperature of about 300 ℃ to about 900 ℃. If the temperature of pyrolysis is less than about 300 ° C or above about 900 ° C, the specific surface area may be reduced. In addition, as the time of pyrolysis increases, the specific surface area of 촤 may increase, but there is no significant difference when it exceeds about 3 hours.

In one embodiment, pyrolysis of the RDF was performed at about 600 ° C. for about 2 hours.

RDF 촤  Step to activate

The activation may include physical activation, chemical activation and ammonia treatment. Through the step of activating the RDF 촤, pores of the RDF 더 are finer, thereby maximizing the surface area and thus having a significant nitrogen oxide reduction efficiency.

Physical activation is activated by using gases such as ozone, CO ₂ , steam, etc. at a high temperature of 300 ° C. or higher, whereby the unstructured portion of the carbide is selectively decomposed and fine pores closed in the carbon structure are opened to increase the internal surface area. Then, carbon crystals constituting carbide or carbon constituting micropores are consumed by the reaction to form large pores.

In this embodiment, the physical activation of the RDF VII may be performed for about 30 minutes to 5 hours at a temperature of about 300 ° C. to about 900 ° C. by placing the RDF VII into the reactor to a water concentration of about 30 vol% to about 50 vol%. have. As the water concentration increases, the specific surface area and porosity of the water may increase. However, when the water content exceeds 50 vol%, there is no significant difference due to the increase of the water concentration. As the activation temperature is increased, the specific surface area and porosity of the char may be increased, but if it exceeds 900 ° C., the specific surface area and porosity may decrease as the intermediate product produced during the pyrolysis process melts. In addition, as the activation time increases, the specific surface area and porosity of 촤 may increase, but when the time exceeds about 5 hours, no significant difference appears.

In one embodiment, physical activation of the RDF VII was performed for about 1 hour at a temperature of about 700 ° C. with a water concentration of about 40 vol%.

Chemical activation is a method of activating chemicals by depositing chemicals and then making fine pores through dehydration and oxidation. As an activator for chemical activation, an alkaline agent such as KOH, NaOH, ZnCl ₂ , K ₂ CO ₃ , and an acid solution such as H ₃ PO ₄ , H ₂ SO ₄ , HNO ₃ may be used. In chemical activation, the addition of chemicals can result in the formation of micropores or enlarged pores.

In this embodiment, RDF VII can be chemically activated with a weight ratio of KOH or NaOH and 1: 1 1: 1 to 2: 1. As the content of KOH or NaOH increases, the specific surface area and porosity of 촤 may be increased. However, when the weight ratio with 촤 exceeds 2: 1, no further difference appears.

In one embodiment, chemical activation of RDF VIII was performed at a weight ratio of KOH and VIII of 1: 1.

Ammonia treatment means a method of activating at a temperature of 200 ℃ or more using NH ₃ consisting of hydrogen and nitrogen. By increasing the nitrogen functional group by ammonia treatment, it can have an improved nitrogen oxide reduction effect.

In this embodiment, the ammonia treatment of the RDF VII may be carried out by placing the RDF VII into the reactor and flowing NH ₃ for about 2 hours at a temperature of about 200 ° C to about 900 ° C. As the activation temperature increases, the specific surface area and porosity of the fin can be increased, but the formation of nitrogen functional groups can be reduced above about 900 ° C.

In one embodiment, the ammonia treatment of the RDF VII was performed for about 2 hours at temperatures of about 300 ° C, about 600 ° C and about 900 ° C.

In addition, the step of activating the RDF VII may further comprise the step of treating the RDF 염 hydrochloric acid (HCl).

The hydrochloric acid treatment step is performed after chemical activation, and by hydrochloric acid treatment of the hydrochloric acid, the heavy metal adsorbed inside the pyrolysis can be effectively eluted, and the active specific surface area of the pyrolysis can be increased to reduce the nitrogen oxide reduction effect. will be.

In this embodiment, the hydrochloric acid treatment of RDF VIII is performed by mixing RDF VIII with hydrochloric acid and stirring at a temperature of about 60 ° C. to about 80 ° C. for about 2 hours, followed by washing with distilled water at room temperature for 30 minutes to 1 hour. Can be performed.

In one example, hydrochloric acid treatment of RDF VII was performed using 5 M hydrochloric acid.

RDF 촤  Manganese processing steps

Manganese treatment means the method of drying and baking after carrying out manganese in 촤. As manganese forms a form of manganese oxide (MnOx), the functional group of the catalyst may be increased, thereby improving the nitrogen oxide reduction effect.

The manganese treatment may be carried out by loading manganese in an RDF ,, drying at a temperature of about 80 ° C. or higher for about 36 to about 48 hours, and then firing at about 300 ° C. or higher for about 2 to 4 hours.

In this embodiment, the weight ratio of RDF VII and manganese may be between 10: 1 and 5: 1. As the content of manganese increases, the nitrogen oxide reduction effect of mu m may increase, but when the weight ratio to mu m exceeds 5: 1, no further difference appears.

In one embodiment, the manganese treatment of RDF shocks was carried out with a weight ratio of 10: 1 to light weights.

According to another aspect, there is provided a catalyst for selective catalytic reduction produced by the process.

The catalyst may have a nitrogen oxide reduction efficiency of at least 40%, at least 45%, at least 50%, at least 55%, or at least 60%.

Hereinafter, the present invention will be described in more detail by way of examples. It will be apparent to those skilled in the art that these embodiments are merely illustrative of the present invention and that the scope of the present invention is not limited to these embodiments.

Example: Preparation of Selective Reduction Catalyst

Example  One: RDF Pyrolysis

The RDF was uniformly filtered to a size of 150 to 200 mesh, and then placed in a U-shaped reactor. Then, pyrolysis was carried out using a Proportional-Integral-Derivative (PID) controller by continuously flowing nitrogen at a flow rate of 50 ml / min at 600 ° C. for 2 hours. As a result, RDF VII was produced as a solid by-product. 1 shows a schematic diagram of the RDF pyrolysis apparatus used above.

In order to determine the physical and chemical properties of the RDF 하여 produced by pyrolysis of the RDF, the four constituents and the contents of the RDF ,, the specific surface area of the RDF 및 and the nitrogen oxide reduction efficiency were analyzed.

The tetracomponent content was measured using industrial analytical methods such as ASTM D1102-84, ASTM E872, ASTM E897-82, and J. Guo. About 0.2 g of RDF was heated from room temperature to 110 ° C. in TGA (Thermal Gravimetric Analyzer, Perkin Elmer-pyris 1) in the presence of nitrogen gas, and then maintained at 110 ° C. for 1 hour to measure moisture content. Volatile content was measured. After nitrogen gas was replaced with oxygen gas, the temperature was lowered to 800 ° C. and maintained until there was no change in the weight of the RDF. The weight change during this time was determined as the content of fixed carbon, and the rest of the ash content was measured.

The element content was measured by using an elemental analyzer (Flash EA 1112 Series, CE Instruments / ThermoQuest Italia) at 1,110 ℃ C, H, N, S content, by measuring the content of O by switching to reducing conditions at 1,060 ℃ It was.

The specific surface area was measured for the nitrogen adsorption and desorption amount of the sample pretreated in a vacuum of 150 ℃, to obtain the isothermal adsorption and desorption curve through this to calculate the specific surface area using Brunaure-Emmett-Teller (BET) theory. .

The nitrogen oxide reduction efficiency is produced by producing a SUS tube having an internal diameter of 260 mm and a height of 1,500 mm and mixing NO, N ₂ , O ₂ , and NH ₃ gas to provide a mass flow controller (Sierra Instruments, Inc., & Hi-Tec Co.). To adjust the flow rate, adjust the concentration of the mixed gas to 1,000 ppm of NO, 1,000 ppm of NH ₃ , 5 vol% of O ₂ and the remaining amount of N ₂ , and use the NOx analyzer (42i-HL, Thermo Ins) to Measured according to:

NOx reduction efficiency (%) = 100 Ｘ (C ⁱ _NO C ^O _NO ) / C ⁱ _NO

(In the above formula, C ⁱ _NO represents the NO concentration (ppm) before the reactor inflow, and C ^O _NO represents the NO concentration (ppm) after the passage of the reactor.)

The four components, elemental content and specific surface area of the RDF VII are shown in Table 1 below:

Component analysis Moisture (wt%) 0.1 Volatilization (wt%) 45.0 Fixed Carbon (wt%) 15.8 Ash (wt%) 39.1 Elemental analysis C (wt%) 74.3 H (wt%) 6.6 O (wt%) 15.9 N (wt%) 3.0 S (wt%) 0.2 Specific surface area analysis m ² / g 30.79

From the results of the component analysis of Table 1, RDF DF has a low water content, high volatile matter and a fixed carbon content, it can be seen that by lowering the production energy required to activate the RDF 생성, the production yield can be increased. . In addition, from the elemental analysis results, since the RDF 촤 has a high content of O, when the RDF DF is activated, it is possible to increase the nitrogen oxide reduction efficiency by increasing oxygen functional groups such as OH, C = O, CO, and the like. Able to know.

The nitrogen oxide reduction efficiency of the RDF VII is shown in FIG.

Referring to Figure 5, RDF 촤 has a low nitrogen oxide reduction efficiency of less than 10%, it can be seen that shows lower activity than activated carbon.

Example  2: RDF 촤  Moisture treatment

The RDF shocks produced by Example 1 were activated by water treatment.

The RDF VII was placed in a U-shaped reactor and heated to 700 ° C. at a temperature increase rate of 5 ° C./min using PID under a water concentration of 40 vol%, and then activated at 700 ° C. for 1 hour. 2 shows a schematic diagram of an apparatus for activation of RDF VII used above.

The specific surface area change of RDF VII before and after moisture treatment is shown in Table 2 below:

BET specific surface area (m ² / g) Before moisture treatment After moisture treatment RDF 촤 30.79 147.02

From Table 2 above, it can be seen that the specific surface area of RDF 증가 increased by treatment with water.

The nitrogen oxide reduction efficiency of RDF VII after water treatment is shown in FIG. 6.

Referring to FIG. 6, it can be seen that the nitrogen oxide reduction efficiency of the RDF increased by about 40% after the water treatment.

Example  3: RDF 촤 KOH  process

The RDF VIII produced by Example 1 was activated by KOH treatment.

Aqueous solution having a mass ratio of KOH and RDF 1: 1 1: 1 was stirred for 2 hours on a hot plate, and dried in an oven at 110 ° C. for more than 24 hours. The dried RDF 촤 was pulverized and placed in a reactor, and the temperature was raised to 5 ° C./min from normal temperature to 700 ° C. while injecting 50 ml / min of nitrogen gas.

Then, to remove the K ⁺ ions remaining in the sample, after neutralizing with 5M HCl, washed with distilled water and put in an oven at 110 ℃ completely dried. 3 shows the above activation process.

The specific surface area change of RDF VII before and after KOH treatment is shown in Table 3 below:

BET specific surface area (m ² / g) Before KOH Treatment After KOH treatment RDF 촤 30.79 575.84

From Table 3 above, it can be seen that the specific surface area was significantly increased by KOH treatment.

The nitrogen oxide reduction efficiency of RDF VII after KOH treatment is shown in FIG. 6.

Referring to Figure 6, after the KOH treatment it can be seen that the nitrogen oxide reduction efficiency of the RDF increased up to about 60%.

Example  4: RDF 촤  Ammonia treatment

The KOH treated RDF VII by Example 3 was activated by ammonia treatment.

RDF VII was placed in a U-shaped reactor and NH ₃ was flown at a flow rate of 50 ml / min for 2 hours at 300 ° C., 600 ° C. and 900 ° C., respectively, using PID. Then, it was purged with N ₂ for 1 hour at room temperature. 4 shows a schematic diagram of an apparatus for treating ammonia of RDF VII used above.

The nitrogen oxide reduction efficiency of RDF 'after ammonia treatment is shown in FIG.

Referring to FIG. 7, it can be seen that the nitrogen oxide reduction efficiency of RDF after ammonia treatment at 300 ° C., 600 ° C. and 900 ° C. is about 60% at a low temperature of 50 ° C., similar to the nitrogen oxide reduction efficiency before ammonia treatment. However, it can be seen that the nitrogen oxide reduction efficiency can be maintained high by treating ammonia at the actual operating temperature of 150 ° C. or higher.

Example  5: RDF 촤  Manganese treatment

Manganese was impregnated with ammonia-treated RDF 에서 at 900 ° C. in Example 4. 10 wt% of manganese was loaded on 5 g of RDF 촤, and then dried in an oven at 100 ° C. for 24 hours. Then, manganese was in the form of manganese oxide (MnOx) and calcined at 350 ° C. for 3 hours to remove impurities.

The specific surface area change of RDF VII before and after manganese treatment is shown in Table 4 below, and the nitrogen oxide reduction efficiency is shown in FIG. 8.

BET specific surface area (m ² / g) Example 1 manganese Before processing After manganese treatment RDF 촤 30.79 541.75 469.63

Referring to Table 4, the specific surface area of RDF 후 after manganese treatment was somewhat reduced compared to that before manganese treatment. Referring to FIG. 8, the nitrogen oxide reduction efficiency was about due to the increase in the active site due to the reaction mechanism of manganese oxide. It can be seen that there is a significant increase by 80%.

Specific structural to functional descriptions are merely illustrated for the purpose of describing the embodiments of the present invention, and the embodiments of the present invention may be embodied in various forms and include all modifications and equivalents included in the spirit and scope of the present invention. It is to be understood to include to substitutes.

Claims (16)

Pyrolysing waste derived fuel to produce waste solid fuel 촤; And
Activating the waste solid fuel ,,
The step of activating the waste solid fuel 것 인 comprises ammonia treatment, the method for producing a catalyst for selective catalytic reduction.
delete delete delete delete delete delete delete The method of claim 1,
The method is carried out by reacting a waste derived fuel 촤 with NH ₃ at 200 ° C. to 900 ° C. and purging with N ₂ at room temperature.
Pyrolyzing the waste derived fuel 촤 to produce the waste solid fuel 촤; And
Activating the waste solid fuel ,,
Activating the waste derived fuel 촤 comprising treating with KOH or NaOH and treating with ammonia.
The method of claim 10,
The method activates a waste derived fuel 촤 with a weight ratio of KOH or NaOH and RDF 1: 1 from 1: 1 to 2: 1; And
Waste solid fuel 촤 is reacted with NH ₃ at 200 ° C. to 900 ° C. and purged with N ₂ at room temperature.
11. The method according to claim 1 or 10,
And manganese treating waste derived fuel 촤 after the activation step.
The method of claim 12,
Wherein the manganese treatment is carried out by supporting manganese in a waste derived fuel tank, followed by drying and calcining.
The method of claim 12,
The weight ratio of manganese and waste derived fuel 촤 is 1:10 to 1: 5.
A catalyst for selective catalytic reduction prepared according to any one of claims 1 and 9 to 11.
16. The method of claim 15,
The catalyst has a nitrogen oxide reduction efficiency of 40% or more.

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