KR20140065969A - Device for purifying exhaust and vessel having the same - Google Patents

Abstract

The present invention relates to an exhaust gas purifying apparatus mounted on a ship. According to one embodiment of the present application, an exhaust gas discharged from an engine is reacted with a reducing agent, and a hydrocarbon is used as the reducing agent, And a reducing agent supply unit for supplying natural gas stored in a natural gas storage tank for liquefying and storing the natural gas as the reducing agent to the catalyst.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a device for purifying exhaust gas,

The present invention relates to an exhaust gas purification apparatus mounted on a ship.

As the industry develops, marine transportation using vessels is expanding. In addition, with the development of industry, concerns about environmental pollution are growing, and many environmental regulations are emerging as countermeasures.

Generally, ships for transporting logistics are propelled by an oil or gas-fueled engine, which inevitably results in exhaust gas.

Among such exhaust gases, particularly, nitrogen oxides (NOx) have a great adverse effect on the environment and are thus subject to major environmental regulations.

On the other hand, the International Maritime Organization (IMO) regulates emission of nitrogen oxides by grade as shown in Fig. 1 for environmental protection.

The emission standards for nitrogen oxides are applied differently in different regions. In particular, Tier 3 grades are applied in emission control areas specifically designated for coastal areas close to land.

In order to satisfy the emission gas regulations as described above, techniques for increasing the efficiency of the engine, changing the fuel to be used, and post-treatment for reducing sulfur compounds (Sox) or nitrogen oxides (NOx) in the exhaust gas have been proposed.

As described above, selective catalytic reduction (SCR) using urea water is widely used for reducing nitrogen oxides among technologies for post-treating exhaust gas among technologies.

As shown in FIG. 2, the selective catalyst reduction method using the urea water is a method in which a catalyst 40 composed of a carrier such as Al 2 O 3 or TiO 2 and an active component such as Pd, Pt, Rd or RU is mixed with the exhaust gas of the engine 10 (Urea) is sprayed as a reducing agent to the exhaust gas before the exhaust gas enters the catalyst (40), so that the nitrogen oxides are reacted in the catalyst (40) so as to be reduced to nitrogen Method.

However, in the selective catalytic reduction of nitrogen oxides using the urea water described above, the urea water used as a reducing agent must be separately stored in the vessel. Therefore, in addition to the fuel tank 20 for storing the fuel, a separate urea water storage tank 50, There is a problem in that a space is required for the number of elements.

In general, the engine of a ship is mainly composed of a diesel engine. The diesel engine uses heavy fuel oil (HFO) or marine diesel oil (MDO).

The heavy oil is relatively inexpensive as compared with light oil, and it must be heated and purified at a certain temperature or higher to be used as a fuel in ships, and more toxic substances such as nitrogen oxides and sulfur oxides tend to be discharged.

In addition, the diesel oil is relatively expensive compared to heavy oil, and the emission of harmful substances is low, but still discharges harmful substances such as nitrogen oxides and sulfur oxides.

On the other hand, engines that use natural gas as a fuel instead of heavy oil or light oil have been developed as ship engine fuel. In the case of an engine using natural gas as described above, the concentration of harmful substances such as nitrogen oxides and sulfur oxides can be drastically reduced in the exhaust gas.

However, due to the characteristics of the natural gas having a very low specific gravity and the characteristics of the marine engine having a low number of revolutions and a very large combustion chamber, some of the natural gas supplied to the combustion chamber can not be burnt and discharged as exhaust gas.

The phenomenon that such unburned fuel is discharged into exhaust gas is called slip. The main component of natural gas is methane (CH4). In the case of methane, the effect of greenhouse effect on global warming is 23 times that of carbon dioxide Given the point, slip methane is a problem that must be solved.

In recent years, a dual fuel engine capable of using all of the heavy oil, diesel, and natural gas as described above has been developed, and an exhaust gas purifying apparatus capable of treating both of nitrogen oxides as well as slip methane There is a growing need.

Korean Patent Publication No. 10-2012-0056476

In order to solve the above problems, the present application is to provide an exhaust gas purifying apparatus capable of treating both nitrogen oxides and slip methane.

Further, the present application is to provide a ship that emits cleaner exhaust gas by mounting a dual fuel engine using heavy oil, light oil or natural gas as fuel.

It is another object of the present application to provide a ship capable of controlling the concentration of harmful substances in the exhaust gas according to the area where the ship is located.

The problems of the present application are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to one embodiment of the present application, there is provided a catalyst for reacting an exhaust gas discharged from an engine with a reducing agent, using a hydrocarbon as the reducing agent to reduce harmful substances in the exhaust gas, And a reducing agent supply unit for supplying natural gas stored in the storage tank to the catalyst as the reducing agent.

The reducing agent supply unit may include a first path unit for supplying evaporated gas vaporized in the natural gas storage tank.

The first supply path portion includes a first line for guiding evaporated gas vaporized and vaporized in the natural gas storage tank to the catalyst, a pumping means for flowing vaporized natural gas in the first line to the catalyst side Lt; / RTI >

The pumping means may include a compressor. The first supply path unit may further include a cooling unit for cooling the natural gas whose temperature has risen through the compressor of the first line.

The reducing agent supply unit may include a second supply path unit for vaporizing and supplying the natural gas liquefied in the natural gas storage tank.

The second supply path portion includes a second line for guiding the liquid natural gas stored in the natural gas storage tank to the catalyst, a pump for flowing the natural gas in the liquid state in the second line to the catalyst side, And a gasification unit for vaporizing the natural gas in the liquid state in the line before the gas is supplied to the catalyst.

Alternatively, the reducing agent supply unit may include a first line for guiding evaporated gas vaporized and vaporized in the natural gas storage tank to the catalyst, a compressor for flowing vaporized natural gas in the first line to the catalyst side, A second line for guiding the liquid natural gas stored in the natural gas storage tank to the catalyst, a second line for guiding the natural gas stored in the natural gas storage tank to the catalyst, And a second heat exchanger for vaporizing the natural gas in the second line before supplying the natural gas in the second line to the catalyst, wherein the first heat exchanger The first and second heat exchangers may cool the evaporation gas using seawater or fresh water or heat the natural gas in the liquid state It is, the first heat exchanger wherein the rough sea water or fresh water may be arranged to pass through the second heat exchanger group.

An exhaust gas sensor for measuring the concentration of harmful substances in the exhaust gas generated in the engine, a supply amount of the reducing agent so that the discharged exhaust gas meets the exhaust gas regulation in the region where the engine is located, The reducing agent supply unit may control the amount of the reducing agent supplied to the catalyst according to a signal from the control unit.

According to the exhaust gas purifying apparatus of the present application and the vessel having the same, the following effects can be obtained.

First, since natural gas is used as the fuel of the engine, the concentration of harmful substances in the exhaust gas can be drastically reduced.

Second, when the engine is applied to an LNG carrier, the natural gas stored in the vessel can be used as fuel, so that a separate fuel tank is not required or the size of the fuel tank can be reduced, thereby enlarging the size of the natural gas storage tank .

Third, natural gas pre-stored in the ship can be used as a reducing agent to be supplied to a catalyst for reducing harmful substances such as nitrogen oxides in the exhaust gas, so that a separate urea storage tank is not needed, And the convenience of operation can be improved since there is no need to purchase the number of elements separately.

Fourth, since natural gas (methane) slipped in the engine can be used as a reducing agent, it is possible to simultaneously treat the slip methane and the nitrogen oxide in the exhaust gas.

The effects of the present application are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

The foregoing summary, as well as the detailed description of the embodiments of the present application set forth below, may be better understood when read in conjunction with the appended drawings. Embodiments are shown in the figures for purposes of illustrating the present application. It should be understood, however, that this application is not limited to the precise arrangements and instrumentalities shown.
FIG. 1 is a table showing an example of regulation of nitrogen oxide emission in the International Maritime Organization;
FIG. 2 is a schematic view of an exhaust gas treatment apparatus of a selective catalyst reduction method using urea water applied to a ship; FIG.
3 is a cross-sectional view schematically showing a state in which an exhaust gas purifying apparatus using hydrocarbons according to the present application is applied to a ship;
FIG. 4 is a view schematically showing a configuration of an embodiment of the exhaust gas purifying apparatus of FIG. 3; And,
Fig. 5 is a view schematically showing the configuration of another embodiment of the exhaust gas purifying apparatus of Fig. 3;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In describing the present embodiment, the same designations and the same reference numerals are used for the same components, and further description thereof will be omitted.

3, the exhaust gas purifying apparatus 100 of the present embodiment is applied to the ship 200 as an example. However, the exhaust gas low boiler of the present invention is not necessarily limited to this, and can be applied to any engine to which exhaust gas is exhausted.

The ship 200 may be an LNG carrier carrying liquefied natural gas (LNG).

The LNG carrier 200 includes a plurality of natural gas storage tanks 210 for storing liquefied natural gas and an engine 230 for propelling the ship 200.

An exhaust pipe 242 for exhausting the exhaust gas generated by the engine 230 may be installed on the stack 240 of the ship 200.

Meanwhile, in the present embodiment, the engine 230 may be a dual fuel engine capable of using natural gas as fuel as well as heavy oil or diesel fuel, which are conventional fuels.

The dual fuel engine may be equipped with heavy oil or light oil as fuel and may use natural gas stored in the natural gas storage tank 210 of the ship 200 as fuel as needed.

That is, since the natural gas stored in the natural gas storage tank 210 of the ship 200 can be used as fuel, the storage amount of the heavy oil or the light oil can be reduced. In the transportation of the liquefied natural gas, Boiling off gas (BOG) generated by the vaporization of liquefied natural gas can be utilized as fuel and the concentration of harmful substances in the exhaust gas can be lowered.

Of course, the engine 230 to which the present invention is applied is not necessarily limited to the dual fuel engine, and can be applied to an engine using conventional heavy oil or light oil as fuel or an engine using only natural gas as fuel.

Meanwhile, exhaust gas is inevitably generated in the engine 230, and the generated exhaust gas can be discharged to the outside through the stack 240 on the exhaust pipe 242.

The exhaust gas purifying apparatus 100 of the present embodiment may be installed on the discharge path of the exhaust gas.

3 and 4, the exhaust gas purifying apparatus 100 according to the present embodiment may include a catalyst 110 and a reducing agent supply unit 120.

The catalyst 110 reacts with the exhaust gas discharged from the engine 230 to reduce the harmful substances in the exhaust gas. At this time, the catalyst 110 of the exhaust gas purifying apparatus according to the present embodiment can be made to use a hydrocarbon-based material as a reducing agent, which is not a conventional urea as a reducing agent. In addition, the harmful substance may be nitrogen oxide (NOx).

A hydrocarbon-based reductant supplied to the catalyst 110 may be a hydrocarbon-containing material such as diesel fuel. In this embodiment, the natural gas storage tank of the ship 200 210 may be used as a reducing agent.

The reducing agent supply unit 120 may supply the natural gas stored in the natural gas storage tank 210 of the ship to the catalyst 110 as the reducing agent.

The natural gas is mainly composed of methane (CH 4). When the natural gas is supplied to the catalyst as a reducing agent, it can be mixed with the exhaust gas and reacted in the catalyst as follows.

2NO + CH4 + O2 - > N2 + CO2 + 2H2O

That is, the nitrogen oxide contained in the exhaust gas in the catalyst 110 reacts with the reducing agent and oxygen, and can be reduced to harmless nitrogen, carbon dioxide, and moisture.

The reducing agent is supplied to the mixer 112 and mixed with the exhaust gas. Then, the catalyst 110 is introduced into the mixer 112 and mixed with the exhaust gas. (Not shown).

The reducing agent supply unit 120 may include a first supply path unit 130 for supplying evaporated gas vaporized in the natural gas storage tank 210 provided in the ship 200.

In the natural gas storage tank 210 of the ship 200, boiling off gas (BOG), which is naturally evaporated by the influence of temperature or pressure, is generated in the liquid natural gas, As a reducing agent.

The first supply path portion 130 may include a first line 132 and a pumping means 134.

One end of the first line 132 is connected to the upper side of the natural gas storage tank 210 and the other side of the first line 132 is connected to a mixer 112 provided at the front end of the catalyst 110, To guide the vaporized vapor into the mixer (112).

The pumping means 134 may be a component that forms a pressure such that the gaseous natural gas in the first line 132 flows to the catalyst 110 side.

Since the gas in the first line 132 is in a gaseous state, the pumping means 134 may be a compressor. When the compressor is applied as the pumping means 134, the temperature of the natural gas passing through the compressor can be raised.

Therefore, the cooling unit 136 for cooling the natural gas whose temperature has risen while passing through the compressor 134 may be provided in front of the mixer 112 of the first line 132.

The cooling unit 136 may be implemented in various ways. In this embodiment, the cooling unit 136 can be implemented in various ways, but in this embodiment, A first heat exchanger configured to cool natural gas by heat exchange with natural gas is applied will be described as an example.

Of course, the heat exchange medium flowing through the first heat exchanger 136 may utilize other materials other than the above-mentioned seawater or fresh water as a heat exchange medium.

A first valve 138 may be further provided on the first line 132 to open or close the first line 132.

The reducing agent supply unit 120 may include a second supply path unit 140 for vaporizing and supplying the natural gas liquefied in the natural gas storage tank 210.

If the first supply path portion 130 uses the evaporation gas already vaporized in the natural gas storage tank 210 as a reducing agent, the second supply path portion 140 may supply liquid to the natural gas storage tank 210 The difference is that natural gas stored in the state is vaporized and supplied.

The second supply path portion 140 may include a second line 142, a pump 144, and a vaporization unit 146.

One end of the second line 142 is connected to the natural gas storage tank 210 and the other side is connected to a mixer 112 provided at a front end of the catalyst 110, To the mixer (112).

The pump 144 may be a component that forms a pressure such that liquid natural gas in the second line 142 flows toward the catalyst 110 side.

Since the natural gas flowing in the second line 142 is a liquid natural gas, it needs to be vaporized and supplied in a gaseous state before being supplied to the catalyst.

Therefore, the vaporization unit 146 is provided at the front end of the mixer 112 on the second line 142 to vaporize the liquid natural gas flowing in the second line 142 and supply the natural gas to the mixer 112 .

The cooling unit 136 may be implemented in various ways. In this embodiment, the cooling unit 136 may be installed in the sea 200, A second heat exchanger 146 for heat-exchanging natural gas with the natural gas and heating the natural gas will be described as an example.

A second valve 148 may be further provided on the second line 142 to open or close the second line 142.

The first line 132 and the second line 142 may be formed as a double pipe so as to be prepared for gas leakage.

The reducing agent supply unit 120 may be composed of only the first supply path unit 130 or the second supply path unit 140 or the combination of the first supply path unit 130 and the second supply path unit 140 .

The first heat exchanger 136 and the second heat exchanger 146 may be arranged in series when the reducing agent supply unit 120 is a combination of the first supply path unit 130 and the second supply path unit 140. [ .

That is, water heated by the natural gas in the heated gaseous state through the first heat exchanger 136 may be heated through the second heat exchanger 146 to heat the natural gas in the liquid state.

An exhaust sensor 234 for measuring the concentration of harmful substances such as nitrogen oxides in the exhaust gas may be further provided at a point where the exhaust gas is discharged from the engine 230.

The natural gas storage tank 210 may be provided with an evaporative gas sensor 212 for measuring the amount of evaporative gas in the natural gas storage tank 210 and a water level sensor 214 for measuring the level of the natural gas in the liquid state have.

A position measuring unit 252 such as a GPS navigation device for measuring the current position of the ship may be provided in the wheelhouse 250 of the ship 200.

In addition, an ECU 232 for monitoring and controlling the operating state such as the number of revolutions of the marine engine 230 may be provided.

The exhaust gas purifying apparatus 100 of the present embodiment may include a control unit 150 for controlling the reducing agent supply unit 120 based on information input from various sensors installed on the ship and pre-stored information.

The control unit 150 may store exhaust gas regulation information.

As shown in FIG. 1, the exhaust gas regulation information may be information on a permissible amount of noxious gas discharge such as nitrogen oxide, which is allowed for each region and engine operation state.

The control unit 150 receives information on the concentration of nitrogen oxides included in the exhaust gas from the exhaust sensor 234 and receives information on the operating state of the engine such as the engine speed from the ECU 232 of the engine And receives information on the amount of the evaporative gas in the natural gas storage tank 210 and the amount of the natural gas in the liquid state from the evaporative gas sensor 212 and the water level sensor 214.

Also, the controller 150 may receive information on the current position of the ship 200 from the position measuring unit 252. Since the engine 230 is provided inside the vessel 200, the current position of the vessel 200 measured by the position measuring unit 252 may indicate the position of the engine 230.

The first valve 138 and the second valve 148 may be opened or closed by a signal of the controller 150. The controller 150 may control the first valve 138 and the second valve 148, And to deliver a signal to open or close valve 148. [

The control unit 150 is provided to transmit a signal for controlling whether the pumping unit 134 and the pump 144 operate and the operation speed of the pump 144. The pumping unit 134 and the pump 144 may be connected to the controller 150 and the operation speed can be controlled by the signal of the controller 150.

That is, the control unit 150 may control the first supply path unit 130 and the second supply path unit 140 to adjust the supply amount and supply amount of the reducing agent supplied to the catalyst 110 .

Therefore, the control unit 150 determines whether or not the information obtained from the exhaust sensor 234, the ECU 232 of the engine, the evaporation gas sensor 212, the water level sensor 214, the position measurement unit 252, And controls the opening and closing of the first valve 138 and the second valve 148 to determine whether or not the pumping means 134 and the pump 144 are operated and the operating speed So that the amount of the reducing agent supplied to the catalyst 110 can be controlled.

For example, when it is determined that the concentration of the harmful substance in the exhaust gas measured by the exhaust sensor 234 is high and the supply of the reducing agent is required to satisfy the emission gas specification, The second valve 148 or the pumping means 134 and the pump 144 to control the amount of the reducing agent so that the amount of the reducing agent can be controlled by controlling the first valve 138, Can be adjusted.

When the amount of the evaporation gas is sufficient, the first valve 138 and the pumping means 134 are controlled to measure the amount of the evaporation gas from the evaporation gas sensor 212, The reducing agent may be supplied through the second supply path portion 140 by controlling the second valve 148 and the pump 144 when the amount of the evaporation gas is insufficient .

Since the unburned methane gas slipped in the engine 230 is also a hydrocarbon-based material, the slipped methane gas contained in the exhaust gas acts as a reducing agent in the catalyst 110 to reduce the nitrogen oxide contained in the exhaust gas .

5, a buffer tank 160 may be further provided for storing natural gas to be used as a reducing agent from the natural gas storage tank 210 in advance.

The buffer tank 160 may be installed on the second line 142 and may include a pump 162 for transferring natural gas from the natural gas storage tank 210 to the buffer tank 160, , And the pump 162 and the valve 164 may be controlled by the controller 150. [

Meanwhile, reference numeral 220, which is not described, may be a fuel tank 220 for storing heavy oil and light oil, which are fuels when the engine 230 is a diesel engine. Of course, the fuel tank 220 may be installed in the case where the engine 230 is a coarse engine using not only heavy oil and light oil but also natural gas as fuel.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. . Therefore, the above-described embodiments are to be considered as illustrative rather than restrictive, and thus the present application is not limited to the above description, but may be modified within the scope of the appended claims and equivalents thereof.

100: Exhaust gas purifying device 110: Catalyst
112: Mixer 120: Reducing agent supply unit
130: first supply path portion 132: first line
134: Pumping means 136: Cooling unit
138: first valve 140: second supply path portion
142: second line 144: pump
146: Heating unit 148: Second valve
150: control unit 160: buffer tank
162: Pump 164: Valve
200: Ship 210: Natural gas storage tank
212: Evaporative gas sensor 214: Water level sensor
220: fuel tank 230: engine
232: ECU 234: exhaust sensor
240: a chimney 242: an exhaust pipe
250: wheelhouse 252: position measuring unit

Claims (8)

A catalyst for reacting an exhaust gas discharged from an engine with a reducing agent, and using hydrocarbon as the reducing agent to reduce harmful substances in the exhaust gas; And
And a reducing agent supply unit for supplying natural gas stored in the natural gas storage tank to the catalyst as the reducing agent. The method according to claim 1,
The reducing agent supply unit,
And a first supply path portion for supplying the evaporated gas vaporized in the natural gas storage tank and vaporized. 3. The method of claim 2,
Wherein the first supply path portion includes:
A first line for guiding evaporated gas evaporated in the natural gas storage tank to the catalyst;
And pumping means for flowing the vaporized natural gas in the first line to the catalyst side. The method of claim 3,
Wherein the pumping means comprises a compressor,
Wherein the first supply path portion includes:
And a cooling unit for cooling the natural gas whose temperature has risen while passing through the compressor of the first line. The method according to claim 1,
The reducing agent supply unit,
And a second supply path portion for vaporizing and supplying the natural gas liquefied in the natural gas storage tank. 6. The method of claim 5,
Wherein the second supply path portion includes:
A second line for guiding the liquid natural gas stored in the natural gas storage tank to the catalyst;
A pump for flowing liquid natural gas in the second line to the catalyst side;
And a vaporization unit for vaporizing the liquid natural gas in the second line before the gas is supplied to the catalyst. The method according to claim 1,
The reducing agent supply unit,
A first line for guiding evaporated gas evaporated in the natural gas storage tank to the catalyst, a compressor for flowing vaporized natural gas in the first line to the catalyst side, a natural gas having a temperature rising through the compressor, A first supply path portion including a first heat exchanger for cooling the first heat exchanger;
A second line for guiding the natural gas in the liquid state stored in the natural gas storage tank to the catalyst, a pump for flowing the natural gas in the liquid state in the second line to the catalyst side, And a second heat exchanger for vaporizing the catalyst before being supplied to the catalyst,
Wherein the first heat exchanger and the second heat exchanger are configured to cool the evaporation gas by using seawater or fresh water or to heat the natural gas in the liquid state and seawater or fresh water passing through the first heat exchanger is placed in the second heat exchanger The exhaust gas purifying apparatus using hydrocarbon. 8. The method according to any one of claims 1 to 7,
An exhaust sensor for measuring the concentration of harmful substances in the exhaust gas discharged from the engine; And
And a control unit for determining a supply amount of the reducing agent so that the discharged exhaust gas satisfies the exhaust gas specification of the region where the engine is located and sending a control signal to the reducing agent supply unit,
Wherein the reducing agent supply unit adjusts an amount of the reducing agent supplied to the catalyst according to a signal from the control unit.

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