KR102474846B1 - Sncr-based plasma nitrogen oxide reduction device for ships - Google Patents

Abstract

The present invention relates to a selective non-catalytic reduction (SNCR)-based plasma nitrogen oxide reduction device for ships to reduce nitrogen oxides by effectively using an SNCR method. According to the present invention, the SNCR-based plasma nitrogen oxide reduction device for ships comprises: an electric dust collection unit inducting engine exhaust gas and generating electrostatic force to collect dust in the exhaust gas; a low-temperature plasma reaction unit including a reactor having a gas inlet into which the exhaust gas transferred by the electric dust collection unit is introduced and into which urea water is introduced, and a microwave generator providing microwaves to the reactor to induce the generation of a low-temperature plasma in the reactor, thereby oxidizing nitrogen oxides of the exhaust gas; an SNCR reaction unit injecting ammonia into the exhaust gas transferred from the low-temperature plasma reaction unit and adjusting a reaction temperature to about 850 to 1,100℃ to remove nitrogen oxides; and a recirculation unit connected to the SNCR reaction unit and the low-temperature plasma reaction unit to transfer the exhaust gas from which the nitrogen oxides have been removed to the low-temperature plasma reaction unit when the nitrogen oxide concentration of the exhaust gas is greater than or equal to a threshold value on the basis of the nitrogen oxide concentration of the exhaust gas from which the nitrogen oxides have been removed.

Description

SNCR-based ship plasma nitrogen oxide reduction device {SNCR-BASED PLASMA NITROGEN OXIDE REDUCTION DEVICE FOR SHIPS}

The present invention relates to a SNCR-based plasma nitrogen oxide reduction device for ships, and more particularly, to a SNCR-based plasma nitrogen oxide reduction device for ships having a low-temperature plasma reaction unit.

In general, representative methods for reducing nitrogen oxides include a selective catalytic reduction method and a selective non-catalytic reduction method. Selective Catalytic Reduction (SCR) is a method of reducing nitrogen oxides by supplying ammonia as a reducing agent through an ammonia injection facility (AIG) downstream of a combustion device to cause a reduction reaction in a catalytic reactor. Selective Non-Catalytic Reduction (SNCR) is a technology that directly injects ammonia water or urea solution into a combustion device and reacts with nitrogen oxides generated through combustion of fossil fuels in the combustion device to reduce it. In recent years, there has been a rapid increase in investment in green technology and movements to respond to climate change worldwide in relation to carbon neutrality. Accordingly, automobiles and freight transportation are being pointed out as the main culprits of air pollution, and environmental regulations are continuously being strengthened for ships that are in charge of one axis of transportation and logistics. As the environmental regulations are strengthened, additional installation of a selective catalytic reduction device is required to obtain a reduction efficiency that cannot be overcome by the selective non-catalytic reduction method. There are many costs and problems. Therefore, there is a need for a method and apparatus capable of effectively achieving denitrification efficiency by utilizing SNCR technology, which can be relatively miniaturized.

The technical problem to be achieved by the present invention is to provide a device and method for reducing nitrogen oxides for ships using Selective Non-Catalytic Reduction (SNCR).

In addition, the technical problem to be achieved by the present invention is to provide a device and method for reducing nitrogen oxides for ships using plasma treatment and selective non-catalytic reduction.

In addition, another technical problem of the present invention is to provide a method and apparatus for controlling nitrogen oxides for ships by using plasma treatment and selective non-catalytic reduction method and effectively controlling by placing a separate, easily detachable catalytic reduction device.

The technical problem to be achieved by the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention is a SNCR-based plasma nitrogen oxide reduction device for ships, comprising: an electric precipitator for collecting dust in the exhaust gas by sucking exhaust gas from an engine by generating electrostatic force; A reactor having a gas inlet into which the exhaust gas transported by the electrostatic precipitator is introduced and into which urea water is introduced, and a microwave generator for inducing low-temperature plasma generation in the reactor by providing microwaves to the reactor, wherein the micro The wave generator includes a magnetron generating microwaves; a coupler for sending the microwave in one direction; a tuner including a plurality of stoves matching the microwave with a load impedance; a quartz barrier through which the microwave passes; and a wave guide for injecting microwaves passing through the quartz barrier into the reactor; A selective non-catalytic reduction (SNCR) reaction unit for removing nitrogen oxides by injecting ammonia into the exhaust gas transported from the low-temperature plasma reaction unit and adjusting the reaction temperature to about 850 to 1100 ° C; And connected to the selective non-catalytic reduction reaction unit and the low-temperature plasma reaction unit, based on the nitrogen oxide concentration of the exhaust gas from which the nitrogen oxides have been removed, to the low-temperature plasma reaction unit when the nitrogen oxide concentration of the exhaust gas is greater than or equal to a threshold value. It provides a SNCR-based plasma nitrogen oxide reduction device for ships, characterized in that it comprises a recirculation unit for transferring the exhaust gas from which the nitrogen oxides have been removed.

In an embodiment of the present invention, the reactor includes a microwave torch, a reducing agent inlet, and a steam inlet, and the plasma reactor is coupled to the reactor, holds the waveguide of the microwave generator, and has a cooling water passage. ; may be further included.

In an embodiment of the present invention, a reducing agent supply unit for supplying the urea water to the reducing agent inlet to react with the exhaust gas in a state in which the low-temperature plasma is formed into the reactor; and a steam supply unit supplying steam to the steam inlet to increase generation of radicals in the reactor.

In an embodiment of the present invention, an inert gas supply unit for supplying an inert gas to exhaust gas from a ship engine; and a PCD unit for performing pulsed corona discharge (PCD) treatment on the exhaust gas mixed with the inert gas and supplying the exhaust gas to the gas inlet.

In an embodiment of the present invention, a catalytic reduction reaction unit for additionally removing the nitrogen oxides using a catalyst after the selective non-catalytic reduction reaction unit; may be included.

According to an embodiment of the present invention, nitrogen oxides can be more effectively reduced using a non-catalytic reduction method.

According to an embodiment of the present invention, as a system combining a low-temperature plasma reactor with a SNCR device, it can be installed through modularization in an existing ship system, so a SNCR-based ship plasma nitrogen oxide reduction device that can be used in replacement demand in addition to new installation can provide

According to an embodiment of the present invention, it is decomposed and burned by reacting with a supplied reducing agent (eg, urea solution) using a microwave plasma flame. That is, microwaves may be generated according to the application of power, and a reducing agent may be guided into the microwave plasma to decompose and burn nitrogen oxides into nitrogen, water, and carbon dioxide.

According to the embodiment of the present invention, a reducing agent for denitrification such as urea (urea solution) or ammonia is suggested as a reducing agent, but the reducing agent can be changed according to the VOC of exhaust gas. The denitrification efficiency can be maximized by providing a reducing agent in a stoichiometric ratio according to the content of nitrogen oxides in the exhaust gas.

According to the embodiment of the present invention, there is also an advantage in that the exhaust gas can be continuously treated without interrupting the operation of the system according to the replacement of the igniter required for flame generation by using the plasma flame as a reactor heat source.

According to the embodiment of the present invention, since the atmospheric pressure plasma is used, the temperature is relatively low, so the risk of fire is low, the VOC decomposition rate is fast, and there is no problem of ozone emission, which is very useful.

According to the embodiment of the present invention, since the plasma energy is used, the processing temperature is relatively lowered to a low temperature, and despite the low temperature, the VOC gas decomposition ability is excellent due to the high energy unique to plasma, and the decomposition reaction occurs at a high speed.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a block diagram of a SNCR-based ship plasma nitrogen oxide reduction device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of the low-temperature plasma reaction unit shown in FIG. 1 .
FIG. 3 is a diagram illustrating an example of a connection unit shown in FIG. 2 .
FIG. 4 is a view showing an example of the reactor shown in FIG. 2 .
5 is a block diagram showing a SNCR-based vessel plasma nitrogen oxide reduction device according to an embodiment of the present invention.
6 is a block diagram showing a plasma nitrogen oxide reduction device for a ship based on SNCR having a recirculation unit according to another embodiment of the present invention.
7 is a block diagram showing a plasma nitrogen oxide reduction device for ships based on SNCR according to another embodiment of the present invention.

Since the present invention may have various changes and various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail.

In general, in order to remove nitrogen oxides, ammonia water containing ammonia is supplied as a reducing agent, and is used to remove nitrogen oxides through a reaction shown in Chemical Formula 1 below on an SCR catalyst. However, since high concentration of ammonia water has a risk of explosion and corrosion, supply to the city center is limited.

[Formula 1]

4NO + 4NH3 + O2 → 4N2 + 6H2O

2NO2 + 4HN3 + O2 → 3N2 + 6H2O

In order to replace this, research is underway to reduce the emission of nitrogen oxides by reducing nitrogen oxides to nitrogen as a precursor for supplying ammonia. For example, various studies are being conducted to use urea solution, which is an aqueous solution of a standardized concentration, and the field of practical application is increasing. However, various problems have been identified when using the number of elements. First, it takes a lot of time to convert urea water into ammonia. Based on overseas application cases, it is reported that the time required to activate the denitrification facility of a power plant using urea water, in particular, to convert urea water into ammonia, is about 30 to 40 min. The second problem is that high temperatures are required for urea solution conversion. Urea water is converted into ammonia through thermal decomposition and hydrolysis of Formula 2 below.

[Formula 2]

CO(NH2)2 → NH3 + HNCO

HNCO + H2O → NH3 + CO2

When nitrogen oxides are removed using ammonia water, the reaction occurs at 250° C. of the SCR catalyst, whereas a temperature required to decompose urea water is approximately 300° C. or higher. When the urea solution decomposition reaction occurs at a low temperature, ammeline or melamine are generated as solid by-products, which can cause great damage to denitrification equipment such as urea water nozzles, pipes, and catalyst surfaces. In addition, when urea water is completely decomposed and not supplied to the SCR catalyst, there is a high possibility that an ammonia slip phenomenon in which ammonia is discharged into exhaust gas due to a urea water decomposition reaction proceeds at the rear end of the SCR catalyst.

In order to solve this problem, high-speed conversion of urea solution may be performed by using a corona discharger for high-speed conversion of urea solution. That is, the corona discharger controls the burner operation to form a high-temperature condition at the time of initial startup, thereby minimizing the time required for urea solution decomposition and suppressing the generation of by-products. In general, a liquid or vapor phase reducing agent is generally accepted to improve the fluidity of the reducing agent and secure stability, but this method is not limited thereto, and various compositions such as urea water, urea (NH2CONH2), ammonia (NH3), A reducing agent such as ammonium carbonate (NH4CO3) or cyanuric acid (HNCO) can be used.

In the present invention, the electrostatic precipitator is a device for separating and removing dust in the exhaust gas by moving it to the wall of the device using electrostatic force. In the case of ships, since the sulfur content is higher than that of general vehicle diesel, the amount of dust generated is high, helping to remove particulate dust. can give

In the corona discharger, NO is oxidized to NO2 and a chemical reaction between NO2, ammonia and minutes is induced, thereby minimizing the energy required to remove NO2 and reducing the power consumption of the entire process. In addition, a reduction in driving power can be expected through a reduction in the energy required to oxidize NO to NO2.

In a microwave plasma generator (low-temperature plasma reactor), plasma of high ionization degree can be performed without excessive heating of gas. In addition, since discharge occurs without internal electrodes, it is possible to design a simple form free from contamination from electrodes, and errors due to electrical interference are small.

The mechanism of denitrification in the plasma discharge process is mainly a reaction between pollutants and radicals, and radicals of OH, H2O, and O mainly participate in the NO oxidation process, and N radicals mainly participate in the reduction process. This can be represented by Formula 3.

[Formula 3]

NO + O → NO2

NO + HO2 → NO2 + OH

NO + O3 → NO2 + O2

NO + OH → HNO2

HNO2 + OH → NO2 + H2O

NO2 + OH → HNO3

NO + N → N2 + O

In addition to the above-described SCR and nitrogen oxide removal methods through plasma discharge, there may be SNCR. In SNCR, ammonia or urea is injected at a high temperature range of about 850 ~ 1100 ℃ to reduce it to nitrogen gas, water, etc. The reaction formula for this is shown in Chemical Formula 4.

[Formula 4]

4NO + 4NH3 + O2 → 4N2 + 6H2O + HEAT

4NO + 2CO(NH2)2 + O2 → 4N2 + CO2 + 4H2O + HEAT

Since the selective non-catalytic reduction method is simple to install and does not use a catalyst, there is no need for installation space in a reactor for installing a catalyst, which may have a space advantage.

Referring to FIGS. 1 to 4, a SNCR-based ship plasma nitrogen oxide reduction device according to an embodiment of the present invention will be described.

1 is a block diagram of a SNCR-based ship plasma nitrogen oxide reduction device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the low-temperature plasma reaction unit shown in FIG. 1 . FIG. 3 is a diagram illustrating an example of a connection unit shown in FIG. 2 . FIG. 4 is a view showing an example of the reactor shown in FIG. 2 .

Referring to FIGS. 1 and 2 , the low-temperature plasma reaction unit 200 of this embodiment may decompose or burn nitrogen oxides in the exhaust gas of the ship and exhaust the exhaust gas. The low-temperature plasma reaction unit 200 may include a microwave generator 210, a connection unit 220, and a reactor 230. The low-temperature plasma reaction unit 200 may further include a reducing agent supply unit 13 , a steam supply unit 14 , and a cooling water supply unit 15 . The low-temperature plasma reaction unit 200 receives a reducing agent from the reducing agent supply unit 13 and steam from the steam supply unit 14, and generates exhaust gas using microwave plasma configured to exist in an ionized state at an appropriate temperature according to the exhaust gas. can be decomposed by combustion. The low-temperature plasma reaction unit 200 may be installed and applied to be connected to the SCR reaction unit as well as the SNCR reaction unit.

The microwave generator 210 may generate and supply microwaves to the reactor 230 . The connection unit 220 is coupled to the reactor 230 and may hold the waveguide 215 of the microwave generator 210 to be positioned on the reactor 230 . An air supply pipe 223 may be formed in the connection part 220 . The connection part 220 may use a quartz tube having a low coefficient of thermal expansion and excellent durability at high temperatures, and the connection part 220 is also called a quartz holder. A cooling water inlet 221 and a cooling water outlet 222 may be formed in the connection part 220 to cool heat generated by long-time operation.

The reactor 230 may include a cylindrical chamber 231, a gas inlet 232 formed in the cylindrical chamber 231, a reducing agent inlet 234, a microwave torch 233, and a steam inlet 235.

The gas inlet 232 may be connected to an exhaust system of the exhaust gas of the ship. For example, as described above, the exhaust gas containing nitrogen oxides of the ship may be discharged and provided to the gas inlet 232 of the low-temperature plasma reactor 200 . The reducing agent supply unit 13 may be connected to the reducing agent inlet 234 and the supply may be controlled by a valve. Steam may be provided from the steam supply unit 14 to the steam inlet 235 according to the type or characteristics of exhaust gas.

Referring to FIG. 1, the microwave generator 210 may include a magnetron 211, a coupler 212, a tuner 213, a quartz barrier 214, and a wave guide 215. can

The microwave generator 210 can form high ionization plasma without excessive heating of the gas. In addition, since discharge occurs without internal electrodes, it is possible to design a simple form free from contamination from electrodes, and errors due to electrical interference are small. The mechanism of denitrification in the plasma discharge process is mainly a reaction between pollutants and radicals, and radicals of OH, H2O, and O mainly participate in the NO oxidation process, and N radicals mainly participate in the reduction process.

The magnetron 211 may be connected to an external high-voltage transporter 250. The high voltage transporter 250 may convert commercial power into high voltage. For example, the high-voltage transporter 250 may convert commercial power of 220V into a high voltage of 22,000V to 24000V. The magnetron 211 may generate microwaves using high voltage provided from the high voltage transporter 250 . For example, the magnetron 211 may convert the transformed high-voltage electrical energy into microwave (wavelength energy) of 2.40 GHz to 2.50 GHz. These specific transformers and the output of the magnetron 211 are just examples and may be appropriately changed according to specific devices or uses. For example, a magnetron 211 with an output of 1Kw may be applied. In addition, it can be modified and applied according to the size and capacity of the reactor 230 in which microwave plasma and flame are radiated.

A coupler 212, a tuner 213, a quartz barrier 214, and a waveguide 215 are installed to generate plasma while minimizing the loss of microwaves (wavelength energy) generated by the magnetron 211. The microwave generated by the magnetron 211 sequentially passes through the coupler 212, the tuner 213, the quartz barrier 214 and the waveguide 215, and may be supplied to the reactor 230 and the microwave torch 233. have.

The coupler 212 may serve to uniformly transmit the wavelength of the magnetron 211 in one direction. The power measurement unit 260 may be connected to the coupler 212 to measure power.

The tuner 213 (tuner) includes a plurality of stoves 2131, and the stoves 2131 are spaced apart from each other at regular intervals and may have a variable length. By varying the length of each stove, it is possible to efficiently transmit maximum energy to the waveguide 215 by minimizing transmission loss of microwaves by matching with the load impedance. The microwave passing through the tuner 213 may pass through the quartz barrier 214 and be supplied to the microwave torch 233 through the waveguide 215 . The waveguide 215 may be composed of a hollow conductor. The waveguide 215 serves to transmit the microwave to the microwave torch 233 with low loss. Cooling water passages are formed in each of the aforementioned parts of the microwave generator 210. As shown in FIG. 3 , cooling water from the cooling water supply unit 15 is supplied to each part of the microwave generator 210 to cool it.

The microwave transmitted by minimizing transmission loss may be transmitted into the reactor 230 through the waveguide 215 . In a state in which the exhaust gas of the ship is injected into the gas inlet 232, it is ignited by the microwave torch 233 and converted into thermal energy to excite the introduced exhaust gas to generate plasma. Plasma generated by the microwave may be injected into the chamber 231 together with the flame. The reducing agent and steam introduced into the reactor 230 may react with the exhaust gas excited by the plasma to decompose and burn the exhaust gas.

As such, in the low-temperature plasma reaction unit 200 of the present embodiment, the reducing agent supplied from the reducing agent supply unit 13 is reacted with exhaust gas to decompose and burn the reducing agent supplied from the reducing agent supply unit 13 using a microwave plasma flame. That is, microwaves may be generated according to the application of power, and nitrogen oxide may be decomposed into nitrogen, water, and carbon dioxide by guiding a reducing agent into the microwave plasma, for example. The valve of the pipe connected to the reducing agent inlet 234 may be opened or closed according to the characteristics of the exhaust gas. That is, in the case of exhaust gas requiring a reducing agent, the valve is opened to supply the reducing agent, and when the reducing agent can be removed by combustion by plasma without supply, the valve of the reducing agent supply line may be closed.

The steam introduced through the steam inlet 235 can stably generate a large amount of hydroxyl radicals by artificially increasing the moisture content of the flue gas injected into the reactor 230 where the low-temperature plasma provided by the low-temperature plasma reaction unit 200 is generated. This can improve the removal efficiency of contaminants.

In this way, the low-temperature plasma reaction unit 200 applies microwave plasma to the exhaust gas and the reducing agent introduced through the gas inlet 232 and the reducing agent inlet 234 to decompose or burn the exhaust gas effectively and efficiently. Can be treated.

As described above, nitrogen oxides in exhaust gas may be decomposed into water, carbon dioxide, and nitrogen by reacting with a reducing agent such as ammonia or urea (CO(NH2)2).

For example, the reaction equation of urea and nitric oxide is:

[Formula 5]

2NO+CO(NH2)2+1/2O2→ 2N2+2H2O+CO2

A specific process temperature is required to react nitrogen oxides with a reducing agent such as ammonia or urea. For example, since the optimum temperature range is 870 to 1050 ° C for ammonia and 900 to 1100 ° C for urea solution (urea), high-temperature exhaust gas conditions are required, and such a narrow operating temperature becomes a major constraint in the actual process. The low-temperature plasma reaction unit 200 of this embodiment adopts a microwave generator 210 to provide low-temperature plasma into the reactor 230 to form such a process temperature. That is, in this embodiment, the microwave generator 210 may provide energy for generating such a low-temperature plasma.

In this embodiment, as described above, the process temperature can be achieved using plasma, but a suitable process temperature can be provided by generating low-temperature plasma using microwave plasma. A reducing agent may be supplied through the reducing agent inlet 234 in order to conveniently provide a process temperature with such plasma and further increase gas decomposition efficiency. Since the reducing agent is supplied, the exhaust gas activated by the plasma reacts with the reducing agent and can be more effectively decomposed. For example, nitric oxide Nox can be decomposed into nitrogen, carbon dioxide and water by reaction with urea as a reducing agent as well as decomposition by plasma.

Meanwhile, the exhaust gas discharged from the ship's engine and treated by the pulsed corona discharge (PCD) unit 101 may flow into the reactor 230 of the low-temperature plasma reaction unit 200 . The PCD may be installed between the exhaust of the vessel and the gas inlet 232 of the reactor 230. The PCD may be a device that collects and treats exhaust gas by pulsed corona discharge. That is, the exhaust gas may be introduced into the gas inlet 232 after being pretreated by pulsed corona discharge. By using PCD to form a high-temperature condition during initial start-up, the time required for exhaust gas decomposition can be minimized and by-product generation can be suppressed.

An inert gas, for example, nitrogen (N 2 ), from the inert gas tank 12 may be supplied to the pipe to be mixed with exhaust gas. Explosion can be prevented and the flow of exhaust gas can be properly maintained by mixing an inert gas such as nitrogen with the exhaust gas discharged from the engine of the ship and discharged to the pipe.

Meanwhile, the three-phase power supply unit 17 may provide power to the PCD 101 and the high voltage transporter 250, respectively.

In this embodiment, a reducing agent for denitrification such as urea or ammonia is suggested as a reducing agent, but the reducing agent can be changed according to the exhaust gas. The denitrification efficiency can be maximized by providing a reducing agent in a stoichiometric ratio according to the content of nitrogen oxides in the exhaust gas.

In addition, there is an advantage in that the exhaust gas can be continuously treated without stopping the operation of the system according to the replacement of the igniter necessary for flame generation by using the plasma flame as a heat source of the reactor 230.

Since the exhaust gas purifier of the present invention uses low-temperature plasma, the temperature is relatively low, so the risk of fire is low, the exhaust gas decomposition rate is fast, and there is no problem of ozone emission, so it is very useful.

Since the exhaust gas purifier of the present invention uses plasma energy, the processing temperature is relatively lowered to a low temperature, and despite the low temperature, the exhaust gas decomposition ability is excellent due to the high energy unique to plasma, and the decomposition reaction occurs at a high speed.

Meanwhile, the selective non-catalytic reduction (SNCR) reaction unit may be implemented as a selective non-catalytic reduction reactor 301 . The nitrogen oxides may be removed by injecting ammonia into the exhaust gas transported from the low-temperature plasma reaction unit inside the selective non-catalytic reduction reactor 301 and adjusting the reaction temperature to about 850 to 1100 ° C.

As described above, nitrogen oxides can be removed through various methods based on the configuration of the selective non-catalytic reduction (SNCR)-based ship nitrogen oxide reduction device. Accordingly, specific embodiments will be described below. However, the embodiments described below may be performed independently or may be performed as one embodiment as a whole, which will be only one embodiment and is not intended to unnecessarily limit the technical features of the present invention.

<First Embodiment>

5 is a block diagram showing a plasma nitrogen oxide reduction device for ships based on SNCR according to an embodiment of the present invention. Referring to FIG. 5, an embodiment for purifying exhaust gas is proposed.

Ships may transfer exhaust gas containing nitrogen oxides generated by an engine or the like to the electric precipitator 100 through a duct or the like. The electrostatic precipitator 100 may separate and remove dust in the exhaust gas by moving it to the wall surface of the device using electrostatic force, and may be specifically performed by the pulse corona discharge unit 101 described above.

Exhaust gas from which dust is removed by the pulse corona discharge unit 101 may be transferred to the reactor 230 of the low-temperature plasma reaction unit 200 .

The low-temperature plasma reaction unit 200 is as described above in FIGS. 1 to 4, and the exhaust gas passing through the pulse corona discharge unit 101 is generated by the plasma generated by the low-temperature plasma reaction unit 200. Nitrogen oxide can be removed or reduced through the above-mentioned chemical reaction. At this time, the pressure inside the reactor 230 may be adjusted for a more effective reaction. Specifically, the plasma reactor is blocked through a blocker that is located at the entrance and exit of the reactor 230 and can block the duct, and seawater flows in the direction opposite to the moving direction of the ship through the entrance and exit, and is introduced while the ship is moving. The internal pressure can be adjusted through a pressurizer capable of adjusting the pressure inside the reactor 230 through hydraulic pressure such as dot water. Exhaust gas from which a certain amount of nitrogen oxides have been removed by the low-temperature plasma reaction unit may be transferred to the selective non-catalytic reduction reaction unit 300 . The selective non-catalytic reduction reaction unit 300 may remove nitrogen oxides by injecting ammonia into the aforementioned selective non-catalytic reduction reactor 301 and adjusting the reaction temperature to about 850 to 1100 °C.

<Second Embodiment>

6 is a block diagram showing a plasma nitrogen oxide reduction device for ships based on SNCR having a recirculation unit according to an embodiment of the present invention. Referring to FIG. 6, an embodiment for purifying exhaust gas is proposed.

Selective non-catalytic reduction is a method that treats exhaust gas through selective catalytic reduction. The concentration capable of removing nitrogen oxides is low. Therefore, in order to carry out the selective non-catalytic reaction in the present invention, a technique for removing nitrogen oxide through a selective non-catalytic reaction through a plasma reaction or the like at the front end has been described above. Accordingly, in this embodiment, the reduction reaction is further performed by the selective non-catalytic reduction reactor 301, and then the nitrate compound concentration is measured. It can be moved to the front of the plasma reaction unit 200. Accordingly, the plasma reaction may be performed again by the low-temperature plasma reaction unit 200 as in the first embodiment, and nitrogen oxide may be removed as in the first embodiment by transferring to the selective non-catalytic reduction unit.

By repeating the above process, the concentration of nitrogen oxides in the exhaust gas may be lower than the threshold value.

<Third Embodiment>

7 is a block diagram showing a plasma nitrogen oxide reduction device for ships based on SNCR having a selective non-catalytic reduction unit and a selective catalytic reduction unit according to an embodiment of the present invention. Referring to FIG. 7, an embodiment for purifying exhaust gas is proposed.

That is, we propose a more efficient nitrogen oxide removal method and device using both a selective non-catalytic reduction unit and a selective catalytic reduction unit.

The selective catalytic reduction unit 500 may be installed at the rear end of the selective non-catalytic reduction unit 300 . In general, the selective catalytic reduction unit 500 is heavier than the non-catalytic reduction unit 300 and occupies a large volume in the ship, so it is installed at the rear end of the non-catalytic reduction unit 300 so that it is detachable, so that each ship can apply

Ships may transfer exhaust gas containing nitrogen oxides generated by an engine or the like to the electric precipitator 100 through a duct or the like.

The electrostatic precipitator 100 may separate and remove dust in the exhaust gas by moving it to the wall surface of the device using electrostatic force, and may be specifically performed by the pulse corona discharge unit 101 described above.

Exhaust gas from which dust is removed by the pulse corona discharge unit 101 may be transferred to the reactor 230 of the low-temperature plasma reaction unit 200 .

The low-temperature plasma reaction unit 200 is as described in FIGS. 1 to 4, and the exhaust gas is nitrogen oxide through the above-described chemical reaction in the reactor 230 by the plasma generated by the low-temperature plasma reaction unit 200. can be removed At this time, for a more effective reaction, the pressure inside the reactor 230 may be specifically adjusted in the same manner as described in Example 2.

Exhaust gas from which a certain amount of nitrogen oxides have been removed by the low-temperature plasma reaction unit may be transferred to the selective non-catalytic reduction reaction unit 300. The selective non-catalytic reduction reaction unit 300 may remove nitrogen oxides by injecting ammonia into the selective non-catalytic reduction reactor 301 and adjusting the reaction temperature to about 850 to 1100 °C. Nitrogen oxides may be partially removed from the exhaust gas by the selective non-catalytic reduction reaction unit 300 and transferred to the selective catalytic reaction unit 500 located at the rear. For example, when the concentration of nitrogen oxides contained in the exhaust gas is greater than a critical value, it may be transferred to the selective catalytic reduction reaction unit 500. In the selective catalytic reduction reaction unit 500, a reduction reaction may be performed by placing a catalyst such as ammonia or urea solution based on Formula 1 or 2 described above. As the catalyst, vanadium and tungsten oxides, manganese and cerium oxides, and zeolite-based catalysts may be used.

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

12: inert gas tank
13: reducing agent supply unit
14: steam supply
15: cooling water supply
17: 3-phase power supply
100: electric dust collector
101: pulse corona discharge unit (PCD)
200: low temperature plasma reaction unit
210: microwave generator
211: magnetron
212: coupler
213: tuner
214: quartz barrier
215: waveguide
220: connection part
230: reactor
231: chamber
232: gas inlet
233: microwave torch
234: reducing agent inlet
235: steam inlet
300: SNCR reaction unit
500: SCR reaction unit

Claims (5)

In the SNCR-based vessel plasma nitrogen oxide reduction device,
An electric precipitator that collects dust in the exhaust gas by sucking in the exhaust gas of the engine by generating electrostatic force;
A reactor having a gas inlet into which the exhaust gas transported by the electrostatic precipitator is introduced and into which urea water is introduced, and a microwave generator for inducing low-temperature plasma generation in the reactor by providing microwaves to the reactor, wherein the micro The wave generator includes a magnetron generating microwaves; a coupler for sending the microwave in one direction; a tuner including a plurality of stoves matching the microwave with a load impedance; a quartz barrier through which the microwave passes; and a wave guide for injecting microwaves passing through the quartz barrier into the reactor;
A selective non-catalytic reduction (SNCR) reaction unit for removing nitrogen oxides by injecting ammonia into the exhaust gas transported from the low-temperature plasma reaction unit and adjusting the reaction temperature to about 850 to 1100 ° C; and
Connected to the selective non-catalytic reduction reaction unit and the low-temperature plasma reaction unit, based on the nitrogen oxide concentration of the exhaust gas from which the nitrogen oxides have been removed, when the nitrogen oxide concentration of the exhaust gas is greater than a threshold value, the low-temperature plasma reaction unit SNCR-based marine plasma nitrogen oxide reduction device, characterized in that it comprises a recirculation unit for transporting the exhaust gas from which nitrogen oxides have been removed.
The method of claim 1,
The reactor includes a microwave torch, a reducing agent inlet and a steam inlet,
The low-temperature plasma reaction unit is coupled to the reactor and holds the waveguide of the microwave generator, and a connection unit in which a cooling water passage is formed.
The method of claim 2,
a reducing agent supply unit supplying the urea solution to the reducing agent inlet to react with the exhaust gas in a state where the low-temperature plasma is formed into the reactor; and
Characterized in that it further comprises a; SNCR-based ship plasma nitrogen oxide reduction device for supplying steam to the steam inlet to increase the generation of radicals in the reactor.
The method of claim 3,
An inert gas supply unit for supplying an inert gas to exhaust gas from a ship engine; and
Characterized in that it further comprises; a PCD (pulsed corona discharge) treatment for the exhaust gas mixed with the inert gas, and a PCD unit for providing the gas to the inlet. SNCR-based vessel plasma nitrogen oxide reduction device.
The method of claim 1,
A SNCR-based ship plasma nitrogen oxide reduction device comprising a; catalytic reduction reaction unit for additionally removing the nitrogen oxides by using a catalyst at the rear end of the selective non-catalytic reduction reaction unit.

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