KR20190138128A - Liquid natural gas combustion apparatus using exhaust heat - Google Patents

Abstract

According to the present invention, a liquefied natural gas combustion apparatus using exhaust heat includes: an LNG tank storing liquefied natural gas; a gasification part gasifying the liquefied natural gas provided from the LNG tank; a fuel heating part heating the liquefied natural gas gasified in the gasification part; a fuel spray device producing a mixture by mixing the fuel heated by the fuel heating part with air by spraying the fuel; a mixture heating part heating the mixture produced by the fuel spray device; an LNG engine creating power by combusting the mixture heated by the mixture heating part, and discharging exhaust gas through a discharge flow path; a first return flow path leading some of the exhaust gas discharged through the discharge flow path to flow into the mixture heating part; and a second return flow path leading some of the exhaust gas discharged through the discharge flow path to flow into the gasification part via the fuel heating part. Therefore, the present invention is capable of maximizing the efficiency of combustion.

Description

Liquefied natural gas combustion apparatus using exhaust heat

The present invention relates to an apparatus for supplying liquefied natural gas to an LNG engine, and more particularly, to a liquefied natural gas combustion apparatus capable of increasing the combustion efficiency of liquefied natural gas by vaporizing and heating liquefied natural gas using exhaust heat. will be.

Natural gas is a fossil fuel containing methane as a main component and a small amount of ethane, propane and the like, and has recently been spotlighted as a low pollution energy source in various technical fields.

Natural gas is consumed by economical and environmentally friendly energy, but is large in volume to be transported as a natural gas, which is a gas, and thus, transportation and storage efficiency is low. To compensate for this, a method of transporting and storing in a liquefied natural gas (Liquefied Natural Gas, LNG) state has been proposed. Liquefied natural gas is a colorless, transparent cryogenic liquid whose natural gas containing methane as its main component is cooled to -163 ° C at atmospheric pressure and reduced in volume to one-600th.

LNG must be vaporized before supplying it to fuels such as engines or power generation. To this end, a system using LNG as a fuel may be provided with a vaporizer or a heater for supplying heat energy to LNG in a cryogenic state of -163 ° C. At this time, in order to supply heat energy to the vaporizer or the heater, separate energy such as electricity is required, and there is a problem in that a device for supplying liquefied natural gas to an LNG engine is complicated and a large maintenance cost is required.

KR 10-2014-0084832 A

The present invention has been proposed to solve the above problems, by using the waste heat of the exhaust gas to vaporize and heat the liquefied natural gas, it is possible to increase the combustion efficiency by heating the mixer to a temperature suitable for the driving conditions of the LNG engine It is an object to provide a liquefied natural gas combustion apparatus using exhaust heat.

The liquefied natural gas combustion apparatus using the exhaust heat according to the present invention for achieving the above object, the LNG tank is stored liquefied natural gas; A vaporization unit for vaporizing liquefied natural gas provided from the LNG tank; A fuel heater for heating the liquefied natural gas vaporized in the vaporizer; A fuel injection device generating a mixer by injecting the fuel heated in the fuel heating unit and mixing the fuel with air; A mixer heater for heating the mixer generated by the fuel injection device; An LNG engine configured to burn power of the mixer heated by the heater to generate power, and to discharge exhaust gas through a discharge passage; A first return passage for introducing a portion of the exhaust gas discharged through the discharge passage into the mixer heating unit; And a second return passage for introducing a portion of the exhaust gas discharged through the discharge passage to the vaporizer through the fuel heating unit.

A first control valve mounted at a point at which the first return flow passage and the discharge flow passage are connected to control a flow rate of the exhaust gas provided to the mixer heater through the first return flow passage; And a second control valve mounted at a point at which the second return passage and the discharge passage are connected to control a flow rate of the exhaust gas provided to the mixer heating unit through the second return passage.

The first return flow passage branches from a point closer to the LNG engine than the second return flow passage in the discharge flow passage.

A first temperature sensor for sensing a temperature of the exhaust gas flowing along the first return passage, a second temperature sensor for sensing a temperature of the exhaust gas flowing along the second return passage, and a flow along the first return passage Controlling the first control valve so that the flow rate of the exhaust gas is inversely proportional to the temperature of the exhaust gas flowing along the first return flow path, and the exhaust flow rate of the exhaust gas flowing along the second return flow path flows along the second return flow path. A control unit for controlling the second control valve to be inversely proportional to the temperature of the gas.

The liquefied natural gas combustion apparatus using the exhaust heat according to the present invention, the LNG tank in which the liquefied natural gas is stored; A vaporization unit for vaporizing liquefied natural gas provided from the LNG tank; A fuel heater for heating the liquefied natural gas vaporized in the vaporizer; A fuel injection device generating a mixer by injecting the fuel heated in the fuel heating unit and mixing the fuel with air; A mixer heater for heating the mixer generated by the fuel injection device; An LNG engine configured to burn power of the mixer heated by the heater to generate power, and to discharge exhaust gas through a discharge passage; And a branching flow path which flows a part of the exhaust gas discharged through the discharge flow path into the fuel heating part and heat-exchanges with the fuel introduced into the fuel heating part, and then branches the vaporization part and the mixer heating part. .

And a branch valve mounted at a point at which the branch passage and the discharge passage are connected to control a flow rate of the exhaust gas provided to the fuel heating unit through the branch passage.

A branch flow path temperature sensor for sensing a temperature of the exhaust gas flowing along the branch flow path, and a control unit for controlling the branch valve so that the flow rate of the exhaust gas flowing along the branch flow path is inversely proportional to the temperature of the exhaust gas flowing along the branch flow path. It further includes.

The liquefied natural gas combustion apparatus using exhaust heat according to the present invention vaporizes and heats liquefied natural gas using waste heat of the exhaust gas, so the internal configuration is simple and the maintenance cost is low. Since it can be heated to a temperature suitable for the driving conditions there is an advantage that can maximize the combustion efficiency.

1 is a schematic diagram of a liquefied natural gas combustion apparatus using exhaust heat according to the present invention.
2 is a schematic diagram of a second embodiment of a liquefied natural gas combustion apparatus using exhaust heat according to the present invention.

Hereinafter, exemplary embodiments of a liquefied natural gas combustion apparatus using exhaust heat according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of a liquefied natural gas combustion apparatus using exhaust heat according to the present invention.

The liquefied natural gas combustor using exhaust heat according to the present invention is a kind of power device that obtains power by burning liquefied natural gas, and by vaporizing and heating the liquefied natural gas supplied to the LNG engine 600 without a separate heating device, The biggest feature of the composition is that it is configured to obtain high combustion efficiency.

That is, the liquefied natural gas combustion apparatus using the exhaust heat according to the present invention, the LNG tank 100 in which the liquefied natural gas is stored, the vaporization unit 200 for vaporizing the liquefied natural gas provided from the LNG tank 100, and Fuel heating unit 300 for heating the liquefied natural gas vaporized in the vaporization unit 200, and fuel injection device 400 for generating a mixer by injecting the fuel heated in the fuel heating unit 300 and mixing with air And a mixer heating unit 500 for heating the mixer generated by the fuel injection device 400 and combustion of the mixer heated by the mixer heating unit 500 to generate power, and through the discharge passage 610. LNG engine 600 for discharging the exhaust gas, a first return passage 710 for introducing a portion of the exhaust gas discharged through the discharge passage 610 into the mixer heater 500, and the discharge passage ( A portion of the exhaust gas discharged through It is configured to include a second return flow path 720 of the fuel is introduced into the carburetor through the yeolbu 300.

The liquefied natural gas stored in the LNG tank 100 is vaporized while passing through the vaporization unit 200 and heated to a predetermined temperature in the fuel heating unit 300, and then the outside air and the like through the fuel injection device 400. Are mixed. The fuel mixed with air (hereinafter, abbreviated as 'mixer') is heated in the mixer 500 again and then supplied to the LNG engine 600 to be combusted. A high temperature exhaust gas is generated while a mixer is combusted in the LNG engine 600. The liquefied natural gas combustion apparatus according to the present invention utilizes heat energy of the exhaust gas instead of emitting the high temperature exhaust gas to the outside. It is configured to vaporize and heat the liquefied natural gas and to heat the mixer.

In this case, since the mixer passing through the mixer heating unit 500 is a mixture of fuel and external air heated to a predetermined level while passing through the fuel heating unit 300, the fuel passing through the vaporization unit 200 or the fuel heating unit 300. It has a relatively high temperature. Therefore, in order to heat the mixer passing through the mixer heating part 500, a relatively high temperature exhaust gas is required, and the first return passage 710 is smaller than the second return passage 720 among the discharge passages 610. It is preferably configured to branch from a point close to the LNG engine 600.

In addition, the amount of heat required to vaporize the liquefied natural gas in the vaporization unit 200 is generally less than the amount of heat required to heat the fuel at a predetermined level or more in the fuel heating unit 300. In this case, since the exhaust gas supplied to the fuel heating unit 300 through the second return flow path 720 has sufficient heat amount to vaporize the liquefied natural gas even though the exhaust gas is exchanged with the fuel and cooled to a predetermined level, the second return flow path As illustrated in FIG. 1, the exhaust gas passing through the fuel heating unit 300 may pass through the vaporization unit 200 as illustrated in FIG. 1. As such, when the second return flow path 720 is configured to sequentially pass through the fuel heating part 300 and the vaporization part 200, a flow path for providing exhaust gas to the fuel heating part 300 and the vaporization part 200. Since it is not necessary to provide each, it is possible to obtain the effect of simplifying the configuration of the combustion apparatus and thereby reducing the manufacturing cost of the combustion apparatus. Of course, in order to supply higher thermal energy to the vaporization unit 200, the return passage for supplying the exhaust gas to the fuel heating unit 300 and the return passage for supplying the exhaust gas to the vaporization unit 200 are each provided independently. May be

By using the liquefied natural gas combustion apparatus configured as described above, the liquefied natural gas can be vaporized and heated without installing a separate heating device as in the prior art, thereby simplifying the overall configuration of the apparatus, It also has the advantage of reducing the energy required to vaporize and heat liquefied natural gas. In addition, since the temperature of the exhaust gas discharged to the outside can be lowered to a certain level, there is an advantage in that it can also help to solve the environmental pollution problem.

At this time, the vaporization unit 200, the fuel heating unit 300 and the mixed heating unit 500 is configured such that the flow path of the fuel or carburetor passes through the inside, and the exhaust gas flow path also passes through the inside, so that the fuel or the carburetor exhaust gas And heat exchange is achieved. As such, a device for exchanging heat between two fluids having a temperature difference has been commercialized in various structures in various fields. Details of the internal structure and operation principle of the vaporizer, fuel heater 300, and mixer heater 500 are described in detail. Description is omitted.

On the other hand, the liquefied natural gas combustion apparatus according to the present invention, the flow rate of the exhaust gas provided to the mixing heater 500 of the exhaust gas flowing along the exhaust flow path 610 and the exhaust gas flowing along the exhaust flow path 610 It may be configured to independently control the flow rate of the exhaust gas provided to the fuel heating unit 300 and the vaporization unit 200, respectively.

That is, the liquefied natural gas combustion apparatus according to the present invention is mounted at a point where the first return passage 710 and the discharge passage 610 are connected, and the mixer heating unit 500 through the first return passage 710. The first control valve 712 for controlling the flow rate of the exhaust gas provided to the), and the second return flow path 720 is mounted at a point where the second return flow path 720 and the discharge flow path 610 are connected. It may be provided with a second control valve 722 for controlling the flow rate of the exhaust gas provided to the mixer heating unit 500 through.

As such, when the first control valve 712 and the second control valve 722 are provided, respectively, the user may supply the amount of thermal energy supplied to the mixer heater 500, the fuel heater 300, and the vaporizer 200. Since the amount of thermal energy supplied can be adjusted respectively, there is an advantage that the combustion efficiency of the LNG engine 600 can be maximized according to various conditions.

In addition, even if the flow rate of the exhaust gas flowing along the first return passage 710 and the second return passage 720 is the same, if there is a difference in the temperature of the exhaust gas, the vaporization unit 200, the fuel heating unit 300, the mixer There may be a difference in the amount of thermal energy supplied to the heat unit 500. Therefore, in the liquefied natural gas combustion apparatus according to the present invention, even if the temperature of the exhaust gas discharged from the LNG engine 600 varies, the amount of thermal energy supplied to the mixed heater 500 and the fuel heater 300 and the vaporizer 200 May be configured to automatically adjust the amount of thermal energy supplied. That is, the liquefied natural gas combustion apparatus according to the present invention includes a first temperature sensor 714 for detecting a temperature of the exhaust gas flowing along the first return flow path 710 and along the second return flow path 720. The second temperature sensor 724 for detecting the temperature of the flowing exhaust gas and the flow rate of the exhaust gas flowing along the first return passage 710 are inversely proportional to the temperature of the exhaust gas flowing along the first return passage 710. And controlling the first control valve 712 so that the flow rate of the exhaust gas flowing along the second return flow path 720 is inversely proportional to the temperature of the exhaust gas flowing along the second return flow path 720. The controller 800 may further include a controller 800 for controlling the valve 722.

As such, the control unit 800 automatically controls the first control valve 712 and the second control valve 722 according to the temperature of the exhaust gas detected by the first temperature sensor 714 and the second temperature sensor 724. When configured to be adjusted, even if the temperature of the exhaust gas discharged from the LNG engine 600 is constantly changed, the amount of thermal energy provided to the mixer heating unit 500, the fuel heating unit 300, and the vaporization unit 200 is kept constant. The bar, there is an advantage that the combustion efficiency of the LNG engine 600 can always be kept constant.

Meanwhile, the filter 310 is mounted at the rear end of the vaporization unit 200 and the rear end of the fuel heating unit 300, and the pressure regulator 320 is mounted between the fuel heating unit 300 and the fuel injection device 400. However, the filter 310 and the pressure regulator 320 are also provided in the conventional liquefied natural gas combustion device the same, the detailed description of the filter 310 and the pressure regulator 320 will be omitted.

2 is a schematic diagram of a second embodiment of a liquefied natural gas combustion apparatus using exhaust heat according to the present invention.

The liquefied natural gas combustion apparatus using exhaust heat according to the present invention may be manufactured to further simplify the structure of the flow path for returning the exhaust gas. That is, the liquefied natural gas combustion apparatus using the exhaust heat according to the present invention, the LNG tank 100 in which the liquefied natural gas is stored, the vaporization unit 200 for vaporizing the liquefied natural gas provided from the LNG tank 100, and Fuel heating unit 300 for heating the liquefied natural gas vaporized in the vaporization unit 200, and fuel injection device 400 for generating a mixer by injecting the fuel heated in the fuel heating unit 300 and mixing with air And a mixer heating unit 500 for heating the mixer generated by the fuel injection device 400 and combustion of the mixer heated by the mixer heating unit 500 to generate power, and through the discharge passage 610. LNG engine 600 for discharging the exhaust gas and a portion of the exhaust gas discharged through the discharge passage 610 into the fuel heating unit 300 to exchange heat with the fuel introduced into the fuel heating unit 300. After the mixing with the vaporization unit 200 It can comprise a branch that provides a branch to the heating portion 500 flow passage 730.

As described above, after the exhaust gas supplied to the fuel heating unit 300 along the branch passage 730 is primarily heat exchanged in the fuel heating unit 300, the exhaust gas is branched into the vaporization unit 200 and the mixed heating unit 500. When it is configured to be supplied, since the exhaust gas can be supplied to both the fuel heating unit 300, the vaporization unit 200, and the mixed heating unit 500 using only one flow path, there is an advantage that the internal configuration becomes very simple.

In addition, as shown in FIG. 2, even when exhaust gas is supplied to the fuel heating unit 300, the vaporization unit 200, and the mixer heating unit 500 by using only one branch passage 730, the branch passage ( 730 may be configured to adjust the flow rate of the exhaust gas flowing along. That is, a branch valve 732 mounted at a point at which the branch passage 730 and the discharge passage 610 are connected to control the flow rate of the exhaust gas provided to the fuel heating unit 300 through the branch passage 730. ) May further include. At this time, since the configuration and function of the branch valve 732 is substantially the same as the first control valve 712 and the second control valve 722 shown in Figure 1, a detailed description of the branch valve 732 is omitted. do.

In addition, even when the liquefied natural gas combustion apparatus according to the present invention has the structure shown in FIG. 2, even if the temperature of the exhaust gas discharged from the LNG engine 600 varies, the fuel heating unit 300 and the vaporization unit 200 may vary. ), Branch flow path temperature sensor 734 for sensing the temperature of the exhaust gas flowing along the branch flow path 730, so that the amount of heat energy supplied to the mixer 500, the branch flow path The controller 800 may further include a controller 800 that controls the branch valve 732 so that the flow rate of the exhaust gas flowing along the 730 is inversely proportional to the temperature of the exhaust gas flowing along the branch passage 730.

When the branch valve 732 is provided in the branch passage 730 as described above, even if the temperature of the exhaust gas is changed irregularly, the fuel heating unit 300, the vaporization unit 200, and the mixer are operated only by the operation of the branch valve 732. Since the amount of thermal energy provided to the heat unit 500 is kept constant, the combustion efficiency of the LNG engine 600 is always maintained constant.

As mentioned above, although this invention was demonstrated in detail using the preferable Example, the scope of the present invention is not limited to a specific Example and should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

100: LNG tank 200: vaporizer
300: fuel heating unit 310: filter
320: pressure regulator 400: fuel injection device
500: mixing heater 600: LNG engine
610: discharge passage 710: first return passage
712: first control valve 714: first temperature sensor
720: second return flow path 722: second control valve
724: second temperature sensor 730: branch flow path
732: branch valve 734: branch flow path temperature sensor
800: control unit

Claims (7)

LNG tank in which liquefied natural gas is stored;
A vaporization unit for vaporizing liquefied natural gas provided from the LNG tank;
A fuel heater for heating the liquefied natural gas vaporized in the vaporizer;
A fuel injection device generating a mixer by injecting the fuel heated in the fuel heating unit and mixing the fuel with air;
A mixer heater for heating the mixer generated by the fuel injection device;
An LNG engine configured to burn power of the mixer heated by the heater to generate power, and to discharge exhaust gas through a discharge passage;
A first return passage for introducing a portion of the exhaust gas discharged through the discharge passage into the mixer heating unit;
A second return passage for introducing a part of the exhaust gas discharged through the discharge passage into the vaporizer through the fuel heating unit;
LNG gas combustion apparatus characterized in that it comprises a. The method according to claim 1,
A first control valve mounted at a point at which the first return passage and the discharge passage are connected to control a flow rate of the exhaust gas provided to the mixer heater through the first return passage;
A second control valve mounted at a point at which the second return passage and the discharge passage are connected to control a flow rate of the exhaust gas provided to the mixer heater through the second return passage;
LNG gas combustion apparatus further comprises a. The method according to claim 2,
A first temperature sensor detecting a temperature of exhaust gas flowing along the first return flow path;
A second temperature sensor for sensing a temperature of exhaust gas flowing along the second return flow path;
The first control valve is controlled such that the flow rate of the exhaust gas flowing along the first return passage is inversely proportional to the temperature of the exhaust gas flowing along the first return passage, and the flow rate of the exhaust gas flowing along the second return passage is increased. A control unit controlling the second control valve to be inversely proportional to the temperature of the exhaust gas flowing along the second return flow path;
LNG gas combustion apparatus further comprises a. The method according to claim 1,
And the first return flow passage branches from a point closer to the LNG engine than the second return flow passage of the discharge flow passage. LNG tank in which liquefied natural gas is stored;
A vaporization unit for vaporizing liquefied natural gas provided from the LNG tank;
A fuel heater for heating the liquefied natural gas vaporized in the vaporizer;
A fuel injection device generating a mixer by injecting the fuel heated in the fuel heating unit and mixing the fuel with air;
A mixer heater for heating the mixer generated by the fuel injection device;
An LNG engine configured to burn power of the mixer heated by the heater to generate power, and to discharge exhaust gas through a discharge passage;
A branching flow path which flows a part of the exhaust gas discharged through the discharge flow path into the fuel heating part and heat-exchanges with the fuel introduced into the fuel heating part, and branches the vaporization part and the mixed heating part;
LNG gas combustion apparatus characterized in that it comprises a. The method according to claim 5,
And a branch valve mounted at a point at which the branch passage and the discharge passage are connected to control a flow rate of the exhaust gas provided to the fuel heating unit through the branch passage. The method according to claim 6,
A branch channel temperature sensor for sensing a temperature of exhaust gas flowing along the branch channel;
A control unit for controlling the branch valve so that the flow rate of the exhaust gas flowing along the branch passage is inversely proportional to the temperature of the exhaust gas flowing along the branch passage;
LNG gas combustion apparatus further comprises a.

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