KR20190012852A - Low energy consumption NOx reduction device equipped with means for heating catalyst by microwave - Google Patents

Abstract

According to the present invention, provided is a low-energy consuming type NO_x removal reaction apparatus having a microwave-used catalyst heating means, and to a NO_x removal method using the same. The low-energy consuming type NO_x removal reaction apparatus of the present invention comprises: a reactor including a gas reactant injection region in a reaction tube, a microwave absorption reaction region having a denitrification catalyst-containing catalyst bed, and a gas product discharge region, in series; and a mocrowave generator for irradiating microwaves to a catalyst layer of the reaction tube. Accordingly, a denitrification catalyst in a reaction region is heated to a desired reaction temperature by a catalyst layer absorbing the microwaves during irradiation of microwaves but an NO_x-containing gas reactant in a reactant injection region and a gas product partially or entirely removed with NO_x in a gas product discharge region are not heated to the reaction temperature.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a low energy consumption NOx removal device equipped with a microwave-

The present invention relates to a low energy consumption type NOx removing reaction device equipped with a microwave utilizing catalyst heating means; And the use thereof.

Nitrogen oxides (NOx) are one of the air pollutants emitted mainly from the combustion process of fuels such as N ₂ O, NO, N ₂ O ₃ , NO ₂ , N ₂ O ₄ and N ₂ O ₅ , NO and NO ₂ are the causes of air pollution and other gases can be neglected in trace amounts. That is, about 90% of NO and about 10% of NO ₂ are included in NO x.

NO is a colorless, odorless gas and hardly soluble in water. NO ₂ is produced by oxidation of NO in the atmosphere, and is converted to nitric acid (HNO ₃ ) by combining with moisture. The production of NO ₂ is affected by weather conditions such as wind speed, solar radiation, temperature, and pollutants. NO ₂ is more soluble than NO, and when it is high, it is reddish brown and odorous.

Nox is the source of photochemical smog by sunlight along with hydrocarbons emitted during combustion. NOx can be odorous even in the presence of 1 to 3 ppm, and it inhibits oxygen transport by reducing the immune system by respiratory diseases and the formation of methemoglobin by reaction with hemoglobin in the blood. NO ₂ is a reddish brown, irritant gas that is 5 times more toxic than NO. Acute damage causes eye, nasal irritation and pulmonary hyperemia, pulmonary edema, obstructive bronchitis and pneumonia.

The factors affecting the production of NOx during combustion include temperature, reaction time, concentration of reactants and mixture of reactants. In the combustion process, the ratio of fuel to air, the temperature of the injection air, By controlling the factor, the occurrence can be suppressed.

The generation of NOx in the atmosphere is divided into a natural source and an artificial source. The natural sources are thunderstorms, volcanic eruptions, bacterial activity, and artificial sources are classified into fixed sources (industrial facilities), migration sources (automobiles, ships, airplanes, diesel locomotives, etc.) Individual heating facilities, etc.), and the types of sources are different than sulfur oxides.

Examples of techniques for removing NOx include an oxidation absorption system, selective non-catalytic reduction (SNCR), selective catalytic reduction (SCR), and the like.

Here, SCR (Selective Catalytic Reduction) is a method in which ammonia is used as a reducing agent to catalyze the chemical reaction of NOx, and TiO ₂ is used as a catalyst. The reaction temperature is in the range of 270 to 350 ° C. , And reduces NOx in the combustion gas to N ₂ and H ₂ O. When an equivalent amount of ammonia, such as nitrogen oxide, is injected, it reacts selectively under a catalyst. The combustion gas is cooled to 200 ° C under SCR and released into the atmosphere through the stack to prevent the occurrence of white smoke.

[Reaction Scheme]

6 NO + 4 NH ₃ ? 5 N ₂ + 6 H ₂ O

6 NO ₂ + 8 NH ₃ → 7 N ₂ + 12 H ₂ O

The SCR process is the most efficient method in the field of denitrification for stationary pollutants among the existing denitrification technologies. At the core of the SCR is the composition of the catalyst and the reactor form, most of which focus on catalysts. The SCR catalyst has a temperature of 250 to 400 ° C, which is the most active, and a high temperature region. However, since the temperature at the stage where the denitration facility can be equipped at the power plant is lower than the temperature at which the denitration catalyst can be activated, the efficiency decreases when these catalysts are applied to the low temperature region of 180 to 250 ° C.

The commercialized V ₂ O ₅ -WO ₃ / TiO ₂ catalyst is installed at the end of the desulfurization facility in consideration of poisoning and life span of SO ₂ , and the temperature of the exhaust gas is drastically reduced through the desulfurization process. Reheating system is required to obtain efficiency. Reheating requires an enormous amount of energy of 2 to 5% of the total power generation of the power plant to raise the temperature of the flue gas by 100 ° C. Therefore, a catalyst having activity at low temperature is required.

However, another problem at low temperatures is the release of unreacted ammonia. Catalyst efficiency is low as there is ammonia is discharged in proportion to the NOx emissions, ammonia itself is a toxic material, and water, when at a low temperature with the NOx to form a NH ₄ NO _3, or SO ₂ flows with NH ₄ HSO _{4, and} so on, thereby deactivating the catalyst. This also shortens the lifetime of the catalyst and reduces the denitrification efficiency. Therefore, the emission of unreacted ammonia should be suppressed. Of course, denitrification efficiency can rise even at low temperatures if sufficient catalyst is provided. However, the space in which the denitration facility can be applied is limited, and pressure loss occurs due to the installation of the denitration catalyst. In the case of a combined-cycle power plant, the power generation efficiency of the gas turbine is reduced in proportion to the pressure loss, .

The NH ₃ to the NH ₃ SCR process with a reducing agent on a V ₂ O ₅ / TiO ₂ catalyst with NOx processing method for generating from the anchorage has been widely used. This V ₂ O ₅ / TiO ₂ catalyst exhibits high NO x removal activity at a temperature range of 300 to 400 ° C. and an O ₂ concentration of 2% or more. On the other hand, the temperature of the exhaust gas, the O ₂ concentration, and the SO x concentration are changed according to the kind of the fuel and the operating conditions, so that the reducing agent, the catalyst and the process must be optimized. However, there is no way to overcome the side effects caused by the use of ammonia as a reducing agent. Therefore, in recent years, the toxicity, explosiveness, and slip of NH ₃ used as a reducing agent in NH ₃ SCR have been problematic, and a catalyst such as CH ₄ , C ₃ H ₆ , C ₃ H ₈ and C ₄ H ₁₀ , Development is underway. However, when hydrocarbons are used as a reducing agent, problems such as hydrothermal phenomena, poisoning by SO ₂ , and by-produced CO must be solved. A series of studies have also focused on excess O ₂ concentration (5-10%) and reaction temperatures above 400 ° C.

On the other hand, diesel vehicles have high output and energy efficiency, but pollutants such as PM, hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxides (NOx) , These pollutant abatement devices are an integral part of the completion of clean diesel. At this time, NOx can be decomposed on the catalyst in the presence of a reducing agent (ammonia, NH ₃ ) through the following reaction mechanism.

4 NO + 4 NH ₃ + O ₂ ? 4 N ₂ + 6 H ₂ O, SCR (1)

_{NO + NO 2 + 2NH 3 →} 2N 2 + 3H 2 O, fast SCR (2)

6 NO ₂ + 8 NH ₃ ? 7 N ₂ + 12 H ₂ O, SCR (3)

In order to reduce nitrogen oxides, a typical exhaust gas purifying apparatus sequentially includes DOC (Diesel Oxidation Catalyst), cDPF and Selective Catalytic Reduction (SCR) at the downstream of the engine, thereby reducing CO, HC and PM together with nitrogen oxide .

Since the devices are mounted on the lower body of the vehicle, there is no spatial margin. Particularly, since the exhaust gas temperature change is large depending on the moving speed of the vehicle, the SCR operating range of 200 ° C or more It is only 50% based on compact cars.

In systems for removing NOx from mobile sources such as automobiles and ships using diesel fuel, small amounts of energy use and miniaturization of the apparatus are required. Accordingly, it is an object of the present invention to provide a reaction apparatus for effectively removing NOx generated only by maintaining a high catalyst bed temperature without additional heating for raising the temperature of the exhaust gas discharged from the source.

A first aspect of the present invention is a low energy consumption type NOx removing reactor equipped with a microwave utilizing catalyst heating means, comprising a gas reactant injection region in a reaction tube, a microwave absorption reaction region provided with a catalyst bed containing a denitration catalyst, A reactor comprising a gaseous product discharge zone in series; And a microwave generator for irradiating a microwave to the catalyst layer of the reaction tube. In the microwave irradiation, the denitration catalyst in the reaction zone is heated to a desired reaction temperature by a catalyst layer that absorbs microwaves. The NOx- And the gaseous product in which the NOx in the gaseous product discharge region is partially or completely removed is not heated up to the reaction temperature.

The second aspect of the present invention provides the NOx-containing exhaust gas discharging apparatus characterized in that the NOx removing reaction apparatus of the first aspect is mounted so as to remove NOx in the exhaust gas.

A third aspect of the present invention provides a NOx removal method by a catalyst, which is characterized in that it is carried out in a NOx removal reactor of the first aspect.

A fourth aspect of the present invention is a chemical reaction apparatus capable of on / off control of a catalytic reaction by a microwave utilizing catalyst heating means, comprising a gas reactant injection region, (i) a catalyst, and (ii) A microwave absorptive reaction zone comprising a catalyst bed containing a SiC-containing diluent which absorbs microwaves and has high thermal conductivity so as to control the on / off of the catalytic reaction, and a reaction comprising a gaseous product discharge zone in series tube; And a microwave generator for irradiating microwave to the catalyst layer.

Hereinafter, the present invention will be described in detail.

According to the present invention, there is provided a low-energy-consumption NOx removing reactor equipped with a microwave utilizing catalyst heating means,

(A) a reactor including a gas reactant injection region in a reaction tube, a microwave absorption reaction region provided with a denitration catalyst-containing catalyst bed (catalyst bed), and a gaseous product discharge region in series; And

And a microwave generating device (b) for irradiating microwave to the catalyst layer of the reaction tube,

During the microwave irradiation, the denitration catalyst in the reaction zone is heated to the desired reaction temperature by the catalyst layer that absorbs the microwave. The NOx-containing gas reactant in the reactant injection zone and the gaseous product in which NOx is partially or completely removed from the gaseous product exhaust zone, It is not heated up to temperature.

Further, according to the present invention, a chemical reaction device capable of on / off control of a catalytic reaction by a microwave utilizing catalyst heating means,

(Ii) a catalyst bed containing a SiC-containing diluent which absorbs microwaves and has high thermal conductivity so as to control on / off of the catalytic reaction by controlling microwave irradiation; A microwave absorptive reaction zone, and a gas product evacuation zone in series; And

And a microwave generating device (b ') for irradiating microwave to the catalyst layer.

Activation energy is the minimum energy required to react. In order for the chemical reaction to proceed, there must be a lot of effective collisions of the particles, and the particles themselves must have a certain amount of energy. This constant energy is the activation energy.

In the NOx removal process, heterogeneous catalytic reaction process, which is a gaseous reactant - solid catalyst system, is in operation and the rate of catalytic reaction increases with increasing reaction temperature.

When a reaction occurs in a chemical reaction, it does not react when the energy required to break the bond, that is, the activation energy, is insufficient. Catalysts are the factors that affect activation energy. The catalyst for producing the reaction intermediate A-S produced by adsorption of the reactant A to the active site S of the catalyst is a catalyst having high activity.

The catalyst has activity to increase the reaction rate of the chemical reaction. When the catalyst is used, the reaction temperature required to maintain the same reaction rate as the chemical reaction using no catalyst can be greatly lowered. Therefore, when the catalyst is used, the overall reaction rate of the chemical reaction can be increased, and the temperature required for the reaction can be lowered, thereby saving energy.

On the other hand, in a chemical reactor using a gas as a reactant, heat is normally supplied from an external heat source (a heating heater, a steam heat exchanger, etc.), and the reactant gas and the catalyst are heated to a required reaction temperature. At this time, the reactant gas generally has a low heat capacity, so that it is necessary to supply a large amount of energy to heat it to a desired reaction temperature. If the gas, which is a reactant, can be supplied with sufficient energy to be activated upon contact with the heated catalyst, only the solid catalyst can be selectively heated up to the reaction temperature without heating the gas as the reactant, So that the present invention has been completed.

Therefore, in the present invention, during the NOx removing reaction by the denitration catalyst, which is an SCR catalyst, the temperature of the NOx-containing gas is not raised by heating to a high temperature at which the denitration catalyst is activated, , A denitration catalyst-containing catalyst layer that absorbs microwaves is designed, and a microwave utilizing catalyst heating means is used.

When the activation energy required for the endothermic catalytic reaction is insufficient, the reaction does not occur. However, in general, the catalytic reaction is almost impossible to stop the reaction in the middle until the reactants heated to the reaction temperature disappear and the reaction is no longer possible. Therefore, the present invention is characterized in that the microwave irradiation is controlled simply and precisely on / off of the catalytic reaction when the catalytic reaction is performed, since the reaction is not heated to the reaction temperature using the microwave, but only the catalyst is heated.

The present invention also relates to a method for controlling the supply of energy corresponding to the required activation energy at a specific temperature of a catalyst by heating the catalyst using a microwave, In view of on / off control of the reaction, a reaction tube including a gaseous reactant injection region, a reaction region having a catalyst layer for absorbing microwave and a gaseous product discharge region in series is used, and the catalyst layer absorbing microwaves has a high thermal conductivity Another feature is the use of an additional diluent. At this time, the diluent is capable of heat transfer with the denitration catalyst, and can preferably absorb microwaves. At this time, the diluent itself may or may not have catalytic activity.

For example, in the present invention, a diluent having a high thermal conductivity (for example, SiC bead) may be mixed with a denitration catalyst-containing catalyst layer in order to heat the catalyst and / or supply thermal energy to NOx gas in contact with the catalyst.

[ Denitration catalyst ]

As the denitration catalyst, a catalyst in which a catalyst component (active metal) is uniformly adhered to a carrier having a large surface area such as aluminum or titanium or a catalyst in which an active metal and a carrier material are mixed and molded is generally used. A transition metal element is used as the active substance.

The active metals of the NOx purification catalyst are shown in Table 1 below.

Nonmetallic element
(Base Metal) Atomic number 23 24 25 26 27 28 29 30 Element name V Cr Mn Fe Co Ni Cu Zn Precious metal element
(Noble Metal) Atomic number 44 45 46 - 75 76 77 78 Element name Ru Rh Pd - Re Os Ir Pt

The denitration catalysts vary in type and shape depending on the type of fuel, the ash content, the sulfuric acid concentration, and the impurity concentration. Temperature, ammonia / NOx molar ratio (NH ₃ / NO x), gas velocity, oxygen concentration, moisture content, gas distribution, etc. are important parameters for determining the size of the catalyst. These denitration catalysts are good in reactivity, less affected by pressure drop, SO ₂ is less converted to SO ₃ , less affected by thermal shock, and easily designed for catalyst replacement.

The denitration catalyst is mainly classified into a metal oxide catalyst and a zeolite.

Non-limiting examples of the metal used in the metal oxide catalyst include V, Fe, W, Cu, Mo, Mn, Ce, Ni and Sn. Reactive with the metal or its compound and the nitrogen oxide is _{Pt, MeO 2, CuO, Fe} 2 O 3, Cr 2 O 3, Co 2 O 3, MoO 3, NiO, WO 3, Ag 2 O, ZrO 2, Al 2 O ₃ , SiO ₂ and PhO. The metal oxide catalyst may be a mixture of two or more metals or compounds having high reactivity with nitrogen oxides. Examples of highly used catalysts include V ₂ O ₅ -Al ₂ O ₃ catalyst, V ₂ O ₅ -SiO ₂ -TiO ₂ catalyst, Pt catalyst, WO ₃ -TiO ₂ catalyst, Fe ₂ O ₃ -TiO ₂ catalyst, CuO-TiO ₂ catalyst and CuO-Al ₂ O ₃ catalyst.

The zeolite catalyst includes a Y-type zeolite catalyst, a Mordenite catalyst, and a ZSM-5 catalyst.

Examples of catalysts used in non-ammonia denitrification processes include zeolitic catalysts, metal oxide catalysts, and noble metal catalysts. Non-limiting examples of zeolite-based catalysts include (1) ion-exchanged zeolites such as Cu, Co, Fe, Zn, Cr, Ni, V, H, Ce, Ga / ZSM- , H, Na-Y), Cu-MFI; (2) Metallo-silicates: Fe-silicate, Ti-silicate; And (3) Silicoaluminophosphates: Cu-SAPO and H-SAPO. Non-limiting examples of the metal oxide catalyst (1) a single metal oxide _{(Single metal oxides): Al 2} O 3, Mn 2 O 3, ZrO 2, TiO 2, SnO 2, La 2 O 3, Rare-earth oxides; (2) a metal-oxide support (Metal-supported oxides): V , Cr, Fe, Zn, Ce, Co, Sr, Cu, Ag / Al 2 O 3, V / TiO 2; (3) Sulfate-treated metal oxides: SO ₄ / TiO ₂ , SO ₄ / ZrO ₂ , Fe ₂ O ₃ ; (4) Mixed oxides and perovskites: ZnO-SiO ₂ and LaAlO ₃ . Non-limiting examples of noble metal catalysts is the _{Rh, Pd, Pt / Al 2} O 3, Pt / SiO 2, Pd / La 2 O 3, Ag / Al 2 O 3, Ag / TiO 2 -ZrO 2. The reaction temperature of the denitration catalyst is in the range of about 320 to 400 ° C. and the NOx reduction efficiency is high and the lifetime of the catalyst is extended.

On the other hand, since the heterogeneous catalysis occurs at the fluid-solid interface, it is necessary to increase the interface area. Thus, the catalyst may be a porous catalyst, a molecular sieve, a monolith, or a supported catalyst. The porous catalyst is a catalyst having a larger area than the pores. The molecular sieve is capable of selective permeation reaction, and has clay and zeolite. Monoliths are non-porous catalysts used in pressure intensification and heat removal processes. The supported catalyst is a catalyst in which fine active material particles are dispersed on a carrier having a large surface area.

On the other hand, the denitration process using a catalyst using ammonia as a reducing agent is widely used because it satisfies the above-mentioned various conditions. However, depending on the characteristics of the exhaust gas, clogging, abrasion or other abrasion may occur due to dust, There is a need for various studies. In the case of a gas (clean gas) containing almost no dust or sulfur oxide as in the case of burning LNG fuel, a flow-through type fixed-bed reactor filled with a granular catalyst is used because the catalyst layer due to dust is not clogged.

In the case of dirty gas containing dust and sulfur oxides in the exhaust gas discharged during heavy oil and coal combustion, a mobile phase type reactor using a particulate catalyst has been employed as a countermeasure against dust, but in recent years, A few parallel-flow fixed-bed reactors are used.

FIG. 6 illustrates the type of the reactor and the shape of the catalyst depending on the kind of the exhaust gas.

[Microwave generator]

The microwave generator may be a magnetron, and the magnetron is a device that generates electromagnetic waves and changes the direction of the electric field at a high speed. The electromagnetic wave that changes the electric field can be used to directly heat the absorbing material.

As an example of a microwave generating apparatus, there is a microwave oven which is a cooking apparatus for heating by a high frequency. The molecules in the high-frequency electric field are strongly vibrated to generate heat, which can be heated evenly in a short period of time. Microwaves are invisible to the eye and pass most of the material. However, when a material that resonates with its own frequency is encountered, it is absorbed by the material and vibrates the molecule. Representative substances are water, followed by fat, carbohydrate, and protein. Therefore, the portion containing the moisture is first heated, and the heat is conducted to the other portion.

The microwave has a wavelength of 1 mm to 1 m and a frequency of 300 GHz to 300 MHz.

In the present invention, a waveguide may be further provided so that only the catalyst layer of the reaction tube and / or the microwave can be uniformly irradiated.

[Material that absorbs microwaves]

The material that absorbs microwaves is polar and has no limitation as long as the direction of the electric field of the microwaves can be rotated and reordered according to the direction of the electric field. The material that absorbs microwaves may be a dielectric substance. Normally, the metal reflects microwaves.

When irradiated with microwaves, the polar molecules rotate very rapidly, aligning them along the electromagnetic field, changing the direction of positive and negative, as the electric field of the electromagnetic wave vibrates in positive and negative directions. As the molecule rotates, molecules push, pull or collide with each other, and this kinetic energy increases the temperature. Temperature is the degree to which molecules move vigorously. Material that absorbs microwaves collides with one another in the process of rearranging molecules. The collided molecules gain kinetic energy and move. The velocity of movement collides with other molecules in the vicinity The temperature of the material that absorbs the microwave can be raised.

The higher the thermal conductivity of the material absorbing microwaves, the better.

In the present invention, the material that absorbs the microwaves may be a catalyst and / or a diluent (a material that is not reactive with a denitration catalysis reaction). The support of the denitration catalyst may be a material that absorbs microwave and / or has a high thermal conductivity.

Non-limiting examples of solid materials that absorb microwaves include: 1) carbon materials such as activated carbon, carbon nanotubes, carbide-based materials such as SiC; 2) SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ and zeolite-based porous silicates or alumino silicate materials; 3) Ni, Cu, and Ag metals.

The microwave absorbing catalyst may be one in which the component acting as the active site is one of the metal components listed in 3) above, or the catalyst carrier is the one listed in 1) or 2) , 3) may be physically mixed.

[Reactor]

In the present invention, the reactor includes a gaseous reactant injection region in a reaction tube, a microwave absorption reaction region provided with a catalyst-containing catalyst bed, and a gaseous product discharge region in series.

A non-limiting example of a reactor is a continuous microwave radial flow fixed bed reactor.

It is preferable that the reaction tube is made of a material through which the microwave is transmitted so that the catalyst layer absorbs the microwave. Quartz, for example, is known as a material that transmits microwaves and does not affect the denitrification reaction.

When the catalyst layer contains the supported catalyst, the active component and / or the support of the catalyst may absorb the microwave.

The catalyst layer may further include a diluent capable of absorbing microwaves, a diluent capable of transferring heat with the catalyst, or a diluent capable of absorbing microwaves and capable of transferring heat to the catalyst. A non-limiting example of a diluent capable of absorbing microwaves and capable of catalytic and heat transfer is SiC beads.

SiC has various advantages such as high strength and hardness, excellent high temperature properties, radiation resistance characteristics, corrosion resistance against etching solution containing HF, and plasma corrosion resistance characteristics. The recently developed high purity sintered SiC and reaction sintered SiC exhibit higher purity, strength and Young 's modulus than fused quartz glass, and have characteristics of low thermal expansion coefficient, high thermal conductivity and low electrical resistance.

By designing a catalyst layer containing an denitration catalyst that absorbs microwaves according to the present invention and using a microwave using catalyst heating means, the reaction temperature in the microwave absorption reaction region is 250 to 400 ° C, The temperature of the NOx-containing gaseous reactant and the temperature of the gaseous product from which the NOx is partially or completely removed in the gaseous product discharge region may be less than 100 占 폚. This is because, during the NOx removing reaction by the denitration catalyst, only the denitration catalyst-containing catalyst layer can maintain the high temperature without increasing the temperature of the NOx-containing gas at a high temperature at which the denitration catalyst exhibits activity through microwave heating.

[ NOx removing reaction device and NOx-containing exhaust gas exhausting device ]

The NOx removing reaction apparatus according to the present invention can be installed to remove NOx from the exhaust gas to the NOx-containing exhaust gas exhausting apparatus to remove NOx. Non-limiting examples of NOx-containing exhaust gases include thermal power plants, automobiles, ships, airplanes, or locomotives.

The apparatus for removing NOx according to the present invention can remove NOx by heating a denitration catalyst layer with a microwave generator having a power consumption of 700 W to 1.2 kW. Therefore, the exhaust gas temperature changes depending on the moving speed of the vehicle increases SCR action range of, keeping the fraction above 200 ℃ a (time average), and even though the light in the 50% to central station compacts reference, NOx removal in accordance with the present invention Since the reaction apparatus is capable of low power consumption and downsizing of the apparatus, it is preferable that the apparatus is used for a moving means for discharging the NOx-containing gas.

The apparatus for removing NOx according to the present invention can effectively remove NOx generated only by maintaining a high catalyst bed temperature without further heating to raise the temperature of the exhaust gas discharged from the source, and it is possible to use a small amount of energy (power) So that it can be mounted on a vehicle body without a space margin.

In addition, it is preferable to use the NOx removing apparatus according to the present invention in order to remove NOx generated from a moving source such as an automobile and a ship using diesel fuel.

Further, the NOx removing reaction apparatus according to the present invention may be provided at the rear end of the desulfurizer, and the NOx-containing gas reactant may be desulfurized. When the desulfurization process is performed, the temperature of the exhaust gas is rapidly reduced, and the exhaust gas needs to be reheated to perform an efficient denitration catalytic reaction. However, even if the NOx removal reactor according to the present invention is installed at the end of the desulfurizer, The reheating means may be omitted.

[On / off of the catalytic reaction by means of the microwave- off control is possible  Chemical reaction device]

According to the present invention, a chemical reaction apparatus capable of controlling on / off of a catalytic reaction by a microwave utilizing catalyst heating means, for example, a NOx removal reaction apparatus, controls microwave irradiation to control the on / Or controlling the amount of light or electric power during microwave irradiation to control the catalytic reaction rate.

For example, a chemical reaction apparatus capable of on / off control of a catalytic reaction can be used,

(Ii) a catalyst bed containing a SiC-containing diluent which absorbs microwaves and has high thermal conductivity so as to control on / off of the catalytic reaction by controlling microwave irradiation; A microwave absorptive reaction zone, and a gas product evacuation zone in series; And

And a microwave generator for irradiating the catalyst layer with microwaves.

The chemical reaction apparatus according to the present invention can be used in the production of a gaseous product through a catalytic reaction from a gaseous reactant without limitation of the catalytic reaction. At this time, the catalytic reaction is preferably an endothermic reaction.

The NOx removal reaction apparatus according to the present invention can effectively remove NOx generated only by maintaining a high catalyst bed temperature without further heating the temperature of the exhaust gas discharged from the source.

1 is a conceptual diagram showing a NOx removal reactor according to an embodiment of the present invention.
2 is a conceptual diagram showing a NOx removal system equipped with a continuous microwave radial flow type fixed bed reactor according to one embodiment of the present invention.
3 is a graph showing the conversion rate with time.
4 is a graph of power vs. temperature versus time.
5 is a temperature comparative graph of the reactor front end, the internal catalyst bed, and the downstream end of the reactor.
6 is a table showing the type of the reactor and the shape of the catalyst depending on the type of the exhaust gas.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for further illustrating the present invention, and the scope of the present invention is not limited by these examples.

[ Example  One]

As shown in FIG. 2, a NOx removal system equipped with a continuous microwave radial flow fixed bed reactor was fabricated. The NOx removal system consisted of a gas injection part, a reaction part, and a reaction gas analysis part. The O ₂ , NH ₃ and NO _x supplied to the reactor were N ₂ balance gas and quantitatively supplied using MFC (Mass Flow Controller).

The fixed - bed reactor with a continuous microwave radiation flow was fabricated from a quartz tube with an inner diameter of 7 mm and a height of 90 mm and a quartz wool and a quartz bead were used to fix the catalyst layer.

The catalyst of V ₂ O ₅ -WO ₃ / TiO _{2 with} an active range of 300-350 ° C was compression molded at a pressure of 300 bar and sieved using a mesh of 30-50 mesh size. 0.5 g (30-50 mesh, 0.7 cc) of the catalyst thus obtained and 1 g (diameter 1.9-2.2 mm) of SiC beads (Silicon Carbide Ceramic Beads) were evenly mixed to fill the reactor.

The temperature of the catalyst layer was auto-tuned to a reaction temperature of 270 ° C with a microwave power supply (1 kW capacity) equipped with a K-type thermocouple above the catalyst layer. The pressure was tested at atmospheric pressure. The reaction conditions of NO and NH ₃ were adjusted to NO 800 ppm and NH ₃ 1000 ppm through the blank line. The total flow rate was 700cc / min and the GHSV (Gas Hourly Space Velocity) was tested under the condition of 60000hr ^-1 . The NO concentration after the reaction through the catalyst layer was measured using a detection tube.

Temperature (° C) 270 N ₂ balance NO (ppm) 800 NH ₃ (ppm) 1000 O ₂ (%) 10 Total flow (cc / min) 700 Space velocity (hr ^-1 ) 60000

In order to remove impurities and moisture from the catalyst in the N ₂ atmosphere, the temperature of the catalyst layer was raised to the reaction temperature of 270 ° C and maintained for 10 minutes. When the experimental temperature reached a steady state, the reaction gas was slowly injected into the reactor and the experiment was started when the concentration of the product reached a certain concentration.

The NOx conversion of the catalyst was defined as follows.

As shown in FIG. 3, when the NOx conversion rate with respect to time was examined, NO concentration of 15 ppm and NO ₂ of 0 ppm reached 98.125% at 3 minutes after the start of the reaction. 10 minutes after the start of the reaction, the NO concentration was maintained at 200 ppm for NOP concentration of 98 ppm for 12 ppm (NO ₂ 0 ppm).

At this time, when the power according to the time and the temperature of the catalyst layer were compared (FIG. 4), the microwave controller's auto-tuning function was used in about 1 minute to 3 minutes to reach the target temperature of 270 ° C. at a high speed. The power required to maintain 270 ° C after reaching was only 40W.

The temperature of the rear end of the reactor, the temperature of the rear end of the reactor, the temperature of the rear end of the reactor, and the temperature of the rear end of the reactor are compared with each other. As shown in FIG. 5, Lt; 0 > C to 60 < 0 & In other words, it can be seen that the catalyst itself is heated by microwave, which is not a type of heating the gas itself but transferring the heat to the catalyst.

Claims (16)

1. A low energy consumption type NOx removing reactor equipped with a microwave utilizing catalyst heating means,
A reactor including a gas reactant injection region in a reaction tube, a microwave absorption reaction region provided with a denitration catalyst-containing catalyst bed, and a gas product discharge region in series; And
And a microwave generator for irradiating microwave to the catalyst layer of the reaction tube,
During the microwave irradiation, the denitration catalyst in the reaction zone is heated to the desired reaction temperature by the catalyst layer that absorbs the microwave. The NOx-containing gas reactant in the reactant injection zone and the gaseous product in which NOx is partially or completely removed from the gaseous product exhaust zone, And the temperature of the NOx removal catalyst is not heated up to the temperature. 2. The NOx removing apparatus according to claim 1, wherein the catalyst layer further comprises a diluent for absorbing microwaves, a diluent capable of transferring heat with the denitration catalyst, or a diluent capable of absorbing microwave and transferring heat to the denitration catalyst. The apparatus according to claim 1, wherein the active component, the support, or both of the denitration catalyst absorbs the microwave. 3. The NOx removal reactor according to claim 2, wherein the diluent capable of absorbing microwave and capable of heat transfer with the denitration catalyst is SiC. 2. The NOx removing apparatus according to claim 1, wherein the reaction tube is made of a material that transmits microwaves so that the catalyst layer absorbs microwaves. The process according to claim 1, wherein the reaction temperature is in the range of from 250 to 400 ° C. with the NO x removal catalyst active, and the temperature of the NO x -containing gas reactant in the gas reactant injection zone and the temperature of the gaseous product in which NO x is partially or wholly removed Lt; RTI ID = 0.0 > 100 C. < / RTI > 2. The NOx removal reactor according to claim 1, wherein the reactor is a continuous microwave radial flow type fixed bed reactor. The NOx removing apparatus according to claim 1, characterized in that the catalytic reaction rate is controlled by controlling the on / off of the catalytic reaction at a desired time by controlling the microwave irradiation, or adjusting the light amount or electric power at the time of microwave irradiation . The NOx removal reactor according to claim 1, wherein the NOx removal reactor is provided at an end of the desulfurizer and the NOx-containing gas reactant is desulfurized. A NOx-containing exhaust gas discharging device, characterized in that the NOx removing reaction device according to any one of claims 1 to 9 is mounted so as to remove NOx from the exhaust gas. 11. The NOx-containing exhaust gas discharging device according to claim 10, wherein the NOx-containing exhaust gas discharging device is a moving device for discharging the NOx-containing gas during operation. 11. The NOx-containing exhaust gas discharging device according to claim 10, characterized in that it is a thermal power plant, an automobile, a ship, an airplane, or a locomotive. 11. The NOx-containing exhaust gas discharging device according to claim 10, wherein diesel is used as the fuel. The NOx removing method according to any one of claims 1 to 9, wherein the NOx removing method is carried out in the NOx removing apparatus according to any one of claims 1 to 9. A chemical reaction apparatus capable of on / off control of a catalytic reaction by a microwave utilizing catalyst heating means,
(Ii) a catalyst bed containing a SiC-containing diluent which absorbs microwaves and has high thermal conductivity so as to control on / off of the catalytic reaction by controlling microwave irradiation; A microwave absorptive reaction zone, and a gas product evacuation zone in series; And
And a microwave generator for irradiating microwave to the catalyst layer. 16. The chemical reaction apparatus according to claim 15, wherein the catalytic reaction is an endothermic reaction.

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