KR101519542B1 - Energy saving apparatus for a ship using waste heat of organic cooling medium - Google Patents

Abstract

An energy saving apparatus for a ship using waste heat of an organic refrigerant is disclosed. According to the present invention, the energy saving apparatus for a ship using waste heat of an organic refrigerant comprises: a mid to low temperature waste heat recovery system operated with an organic refrigerant having a boiling point lower than the boiling point of water as a working fluid; a waste heat recovery system generating electricity with an exhaust gas exhausted from a plurality of engines provided in a ship as the working fluid and enabling supply water, which is supplied to a heat exchanger to operate a steam turbine, heat exchanged with the organic refrigerant in a condenser of the mid to low temperature waste heat recovery system; an exhaust gas recirculation system recirculating a portion of the exhaust gas to be supplied to the engines and enabling the exhaust gas and the supply water to be heat exchanged in a front end of the heat exchanger; and an engine scavenging cooling unit enabling the heat waste of an scavenge air to be heat exchanged with the supply water in the front end of the heat exchanger.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an energy saving device for a ship using waste heat of an organic refrigerant,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy saving device for a ship, and more particularly, to an energy saving device for a ship, which uses waste heat discharged from a condenser of a low- and medium-temperature waste heat recovery system operating with an organic refrigerant having a boiling point lower than water, The present invention relates to an energy saving device for a ship using waste heat of an organic refrigerant capable of maximizing the recovery of waste heat by using a scavenge air waste heat source.

Generally, about 50% of the thermal energy generated by combustion of fuel in a propulsion or power generation engine of a ship is used for propulsion or power generation, respectively, while the remainder is mostly used for cooling the exhaust gas or heat- And the like. The heat emitted in this form can be said to be a waste heat that can not be converted to a form useful for propulsion or power generation of an engine, and is therefore referred to as waste heat.

Therefore, if some of the waste heat discharged to the outside is recovered and can be recycled as useful energy, it is possible to save the fuel, thereby contributing to saving the total energy consumed by the ship.

As a result, there has recently been a demand for a highly efficient vessel or an eco-friendly vessel capable of reducing energy by recovering a part of waste heat discharged to the outside. Already in the marine sector, gas turbines (or power turbines), which use high-temperature exhaust gases discharged from the engine as direct working fluids for a few years, and some of the steam generated by the heat of high-temperature exhaust gases, (WHRS: Waste Heat Recovery System), which is capable of generating electricity by additionally installing steam turbines.

In recent years, the number of ship owners who need to reduce the fuel cost by operating the ship at a low speed increases the output of the engine to about 30% ~ 50% of the maximum output when the ship is operated at low speed.

Since the exhaust gas temperature is low when the engine is operated with such a low load, the conventional waste heat recovery apparatus using the high temperature heat will not perform its role properly. That is, the gas turbine and the steam turbine of the conventional waste heat recovering apparatus were able to recover heat only from the heat source of about 250 degrees Celsius or more and to produce electrical energy through the heat source. However, the heat of the lower temperature could not be utilized yet, There is no problem.

In addition, the conventional waste heat recovery apparatus of the conventional ship recovers relatively high heat from the discarded heat energy to produce electric power, so that when the engine is operated at a high load, a large amount of heat can be recovered to produce electric power. However, when the engine is operated at a low load, the exhaust gas, that is, the temperature of the waste heat is relatively low, and the utility of the power generation is deteriorated.

Accordingly, there is a demand for an apparatus capable of operating as a heat source of low-temperature and low-temperature waste heat of about 100 to 250 degrees Celsius. Such a device is disclosed in Korean Patent Application No. 10-1328401 filed by the present applicant ).

In other words, the low-temperature on-site heat recovery system is a turbine cycle that operates using an organic refrigerant having a boiling point lower than that of water as a working fluid, and is generally referred to as an ORC (Organic Rankine Cycle) apparatus. Because it uses organic refrigerant with lower boiling point than water, it can operate with lower temperature as heat source than steam turbine which uses water as working fluid and can produce electric energy using waste heat of less than 250 degrees Celsius .

The above-described embodiment is limited to supplying the waste heat from the ship to the evaporator of the medium-low-temperature waste heat recovery apparatus, and there is no discussion about the heat source of the organic refrigerant that is discarded as it is in the process of condensation in the condenser.

In other words, the organic refrigerant supplied to the condenser of the middle and low-temperature waste heat recovery unit is condensed by fresh water of about 36 degrees supplied to the condenser. In this process, the heat of the organic refrigerant is all discarded by the fresh water There is a need for a way to utilize this.

On the other hand, when a plurality of main engines are provided for the propulsion of the ship, the amount of scavenge air supplied to each main engine is increased, and the waste heat of the scavenge air is increased accordingly. There is also a request.

The above-described technical structure is a background technique for assisting the understanding of the present invention, and does not mean the prior art widely known in the technical field to which the present invention belongs.

Korean Patent Registration No. 10-1328401 (Daewoo Shipbuilding & Marine Engineering) 2013.11.06.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a low-temperature waste heat recovery system using waste heat discharged from a condenser of a low-temperature waste heat recovery system operating with an organic refrigerant having a boiling point lower than that of water, The present invention provides an energy saving device for a ship using waste heat of an organic refrigerant capable of maximizing the recovery of waste heat using a waste heat source of a ship.

According to an aspect of the present invention, there is provided a low-temperature, waste heat recovery system that operates using an organic refrigerant having a boiling point lower than that of water as a working fluid; A waste heat recovery system in which water supplied from a plurality of engines provided in a ship to a heat exchanger for driving the steam turbine is used for heat exchange with a condenser of the medium and low-temperature waste heat recovery system using the exhaust gas discharged from a plurality of engines as a working fluid, ; An exhaust gas recirculation system for recirculating a part of the exhaust gas to supply the exhaust gas to the plurality of engines while exchanging heat between the exhaust gas and the feed water at a front end of the heat exchanger; And an engine scavenging unit for heat-exchanging waste heat sources of scavenge air from the front end of the heat exchanger with the water supply, can be provided.

The engine scavenge cooling unit may further heat the water feed exchanged and discharged in the exhaust gas recirculation system.

The engine scavenge cooling unit may heat the incoming water to the exhaust gas recirculation system prior to the exhaust gas recirculation system.

The exhaust gas recirculation system includes: a scrubber for removing impurities contained in exhaust gas discharged from the plurality of engines; A cooler for cooling the exhaust gas supplied from the scrubber; And a blower blowing the exhaust gas cooled in the cooler to mix with exhaust gas supplied from the supercharger to the engine and to be supplied to the plurality of engines.

Wherein the cooler includes a first cooler for primarily cooling the exhaust gas by exchanging heat between the exhaust gas discharged from the scrubber and water circulated in the waste heat recovery system; And a second cooler for cooling the exhaust gas by exchanging heat between the exhaust gas discharged from the first cooler and a liquid separate from the feed water.

Further comprising a water supply heat exchanging unit for connecting the low-temperature on-site heat recovery system and the waste heat recovery system to heat exchange with each other, wherein the water supply heat exchange unit is branched from a front end line of the heat exchanger, Branch line; And a direction control valve provided at an intersection of the branch line and the end line to supply the water to the heat exchanger by bypassing the condenser or the condenser.

And a cooling water circulation system having a main flow passage through which cooling water for cooling the engine flows and supplying a waste heat of the cooling water to the evaporator of the low-temperature on-site waste heat recovery system.

The cooling water circulation system may further include a cooling water heat exchanger for exchanging heat between cooling water flowing through the main flow path and feed water flowing into the exhaust gas recirculation system.

The engine may be a main engine, and the vessel may include a container line.

Embodiments of the present invention can maximize the recovery of waste heat and reduce the energy by exchanging the water supplied to the heat exchanger for driving the steam turbine of the waste heat recovery system with the organic refrigerant in the condenser of the medium and low-temperature waste heat recovery system.

Also, when a plurality of engines are provided, the scavenge air waste heat generated in each engine can be used in the waste heat recovery system, thereby maximizing the waste heat recovery.

1 is a schematic view illustrating an energy saving device for a ship using waste heat of organic refrigerant according to a first embodiment of the present invention.
FIG. 2 is a view schematically showing an energy saving device for a ship using waste heat of organic refrigerant according to a second embodiment of the present invention.
3 is a schematic view illustrating an energy saving device for a ship using waste heat of organic refrigerant according to a third embodiment of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

1 is a schematic view illustrating an energy saving device for a ship using waste heat of organic refrigerant according to a first embodiment of the present invention.

As shown in this figure, an energy saving device (1) for a ship using waste heat of an organic refrigerant according to the present embodiment comprises a medium and low temperature waste heat recovery system (100) operated with an organic refrigerant having a boiling point lower than water as a working fluid A waste heat recovery system 200 for generating electric power by using exhaust gas discharged from an engine E as a working fluid and a heat exchanger 280 for driving a steam turbine 210 of the waste heat recovery system 200 A water supply heat exchanging unit 300 for exchanging water supplied from the condenser 140 with the organic refrigerant in the condenser 140 of the medium and low-temperature waste heat recovery system 100, and a main flow path 410 through which cooling water for cooling the engine E flows A cooling water circulation system 400 for supplying the waste heat of the cooling water to the evaporator 110 of the low- and medium-temperature waste heat recovery system 100 and a cooling water circulation system 400 for circulating a part of the exhaust gas to a plurality of engines E, ) At the front end of the exhaust gas and water column And an exhaust gas recirculation system 500 for exchanging exhaust gas.

The intermediate low-temperature waste heat recovery system 100 is a turbine cycle operated by using an organic refrigerant having a boiling point lower than that of water as a working fluid, and is generally referred to as an organic Rankine Cycle (ORC).

In this embodiment, since the middle and low-temperature waste heat recovery system 100 can use an organic refrigerant having a boiling point lower than that of water, for example, R 134a, it can operate with a lower temperature as a heat source than a steam turbine using water as a working fluid, The electric energy can be produced by using the waste heat of about 100 캜 generated from the waste heat.

In this embodiment, the jacket cooling fresh water, which is a heat source having a temperature lower than that of steam used in a conventional ship, is used as a heat source and a heat transfer material for evaporating the organic refrigerant, which is an operating oil of the low / medium heat recovery system 100, And the total energy consumed by the ship can be saved.

1, the intermediate-low-temperature waste heat recovery system 100 is configured to evaporate the organic refrigerant through heat exchange with the cooling water transferred from the engine E, as shown in FIG. 1 An evaporator 110, a turbine 120 rotated through the organic refrigerant evaporated by the evaporator 110, a generator 130 generating electricity by interlocking with the rotation of the turbine 120, a turbine 120 A condenser 140 for cooling and liquefying the organic refrigerant from the evaporator 110 and a condenser 140 for condensing the condensed organic refrigerant from the condenser 140 to the evaporator 110, And a conduit 160 forming a circulation path of the organic refrigerant to the condenser 140 and the pump 150.

In this embodiment, the heat source, which is the cooling water supplied from the engine E, has a temperature of about 80 DEG C, but the temperature rises to about 86 DEG C while passing through the dumping condenser unit 440, 450), the temperature rises to about 106 ° C. The heat source, which is the coolant whose temperature is raised in this way, falls to about 80 ° C after heat exchange with the evaporator 110.

The low-temperature on-the-fly heat recovery system 100 is characterized in that high efficiency can be obtained as the temperature difference between the high temperature portion heated by the evaporator 110 and the low temperature portion cooled by the condenser 140 is larger, as in the other turbine systems. That is, the higher the temperature of the high temperature portion that flows into the evaporator 110 and transfers heat to the evaporator 110, the lower the temperature of the low temperature portion that flows into the condenser 140 and condenses the organic refrigerant, the higher the efficiency.

The waste heat recovery system 200 generates electric power by using a high temperature exhaust gas discharged from the engine E directly as a working fluid or a part of the steam generated by using heat of a high temperature exhaust gas as a working fluid It plays a role.

1, the waste heat recovery system 200 includes a gas turbine (not shown) that is directly driven by exhaust gas discharged from a plurality of engines E and provides driving force for rotating the generator 130 A steam turbine 210 interlocked with the gas turbine 220 and providing driving force for rotating the generator 130 by steam provided from a heat exchanger 280 to be described later, A water pump 240 for pumping the condensed water in the condenser 230 and a water supply line 240 for supplying the water to the vacuum degassing apparatus 250, A control valve 250 that opens or closes the condensate discharge line to be transferred to the base 260 or circulated to the condenser 230 and a vacuum degasser 260 in which the condensed water condensed in the condenser 230 is stored. T is a water supply tank, and the vacuum degassing unit 260 may be a vacuum degassing tank for removing dissolved oxygen from the water supplied to the vacuum.

1, the waste heat recovery system 200 includes a heat exchanger feedwater pump 270 for pumping the water stored in the vacuum degassing unit 260 toward a water feed heat exchanging unit 300 to be described later, A heat exchanger 280 for exchanging heat between the feed water heat-exchanged in the heat exchanger feed pump 270 and exhaust gas discharged from the engine E to generate steam for driving the steam turbine 210, a heat exchanger 280 And a steam separator 290 for separating the steam and water from the steam generated in the steam generator.

In this embodiment, the heat exchanger 280 may be provided in multiple stages in order to improve heat exchange efficiency. In this embodiment, since a plurality of engines E are provided, the heat exchanger 280 is provided in the number of the engines E May be provided in a corresponding number.

In the present embodiment, a plurality of heat exchangers 280 are provided, so that the rear end line of the heat exchanger feedwater pump 270 is branched into a plurality of lines and connected to the respective heat exchangers 280 do. The water heat exchanged in each of the heat exchangers 280 is supplied to the steam separator 290 through one combined line and the steam separated from the steam separator 290 is again supplied to the respective heat exchangers 280. The steam supplied to each of the heat exchangers 280 is heat-exchanged with the exhaust gas passing through the turbocharger TC, and then supplied to the steam turbine 210.

1, the water supply heat exchanging unit 300 is provided in a line between the heat exchanger water feed pump 270 and the heat exchanger 280 and is supplied to the heat exchanger 280 for driving the steam turbine 210 And serves to exchange heat with the organic refrigerant in the condenser 140 of the waste heat recovery system 100.

In the conventional method, that is, in the method of supplying fresh water which is cooling water for condensing the organic refrigerant in the condenser, the heat source of the organic refrigerant has to be thrown away. For reference, the temperature of the fresh water supplied to condense the condenser is about 36 degrees.

However, in this embodiment, the steam turbine 210 is driven by the water supplied to the heat exchanger 280 (about 27 to 30 degrees lower than the temperature of the fresh water of about 36 degrees supplied to the cooling water of the condenser 140) And the condenser 140 of the low-temperature on-the-fly heat recovery system 100 through the water feed heat exchanging unit 300 so as to perform heat exchange with the organic refrigerant.

As a result, since the waste heat of the organic refrigerant discharged from the condenser 140 of the low-temperature waste heat recovery system 100 can be recovered, energy can be saved by maximizing the waste heat recovery.

1, the water supply heat exchanging unit 300 is branched from the front end line of the heat exchanger 280 and passes through the condenser 140 of the low-temperature and waste-heat recovery system 100, And a direction control valve (not shown) provided in an intersecting region of the branch line 310 and the leading line and supplying water to the heat exchanger 280 by bypassing the condenser 140 or the condenser 140 320).

The direction control valve 320 of the water supply heat exchanging unit 300 may be provided at a distance from the line connecting the heat exchanger water feed pump 270 and the heat exchanger 280 as shown in FIG. The directional control valve 320 disposed closest to the heat exchanger feedwater pump 270 among the pair of directional control valves 320 is connected to the condenser 140 or the condenser 140 through a water feeder provided from the heat exchanger feedwater pump 270, To the heat exchanger (280). The remaining directional control valve 320 may prevent the feed water bypassing the condenser 140 from flowing back to the condenser 140.

In this embodiment, the directional control valve 320 may be a three-way valve, and the three-way valve may be an electronic control valve operated by an electrical signal. Further, the directional control valve 320 disposed closest to the heat exchanger 280 may be a check valve.

On the other hand, when the organic coolant is not sufficiently cooled due to insufficient cooling capacity of the water supplied from the water supply heat exchanger 300, the efficiency of the low-temperature on-site heat recovery system 100 may be lowered or equipment problems may occur.

In order to prevent such a problem, in this embodiment, a separate line through which fresh water flows at about 36 degrees is provided in the condenser 140, and the cooling capacity of the water supply is supplemented by exchanging the fresh water supplied through the separate line with the organic refrigerant The stability of the system can be enhanced.

The fresh water flowing through the separate line, the water flowing through the branch line 310, and the line through which the organic refrigerant flows can be provided as independent lines that are not merged with each other.

The cooling water circulation system 400 circulates a heat source as cooling water to cool the engine E and is connected to the engine E and the main flow path 410 to be supplied to the engine E A jacket cooler 420 for cooling the cooling water as a heat source and cooling water which is provided in the main flow path 410 for connecting the jacket cooler 420 and the engine E and which is a heat source cooled by the jacket cooler 420, E), and a cooling water circulation system 400. The cooling water circulation system 400 heat-exchanges the heat source with the dumping steam transferred from the steam system of the ship to the low-temperature on-site heat recovery system 100 A dumping condenser unit 440 for raising the temperature of the cooling water and condensing the heat-exchanged dumping steam, and a cooling water whose temperature is increased in the dumping condenser unit 440 to raise the temperature of the cooling water from the turbocharger TC of the engine E Desired air and heat supply And an engine scavenging unit 450 for further increasing the temperature of the cooling water transferred to the intermediate-low-temperature waste heat recovery system 100 and cooling the heat-exchanged scavenged air.

The engine E of the cooling water circulation system 400 can use a heat-resistant engine such as a two-stroke diesel engine and can be a main engine that drives a ship.

The dumping condenser unit 440 of the cooling water circulation system 400 serves to cool the remaining steam used in the ship by the low temperature cooling water and condense it into water.

1, the dumping condenser unit 440 includes a first condenser module 441 for increasing the temperature of the cooling water by mutually exchanging heat between the cooling water and the dumping steam, a first condenser module 441, A second condenser module 442 for cooling and condensing the heat-exchanged dumping steam through the first condenser module 441 and a second condenser module 442 provided in a rear line of the first condenser module 441 to allow cooling water to flow to the first condenser module 441, A first directional control valve 443 for preventing the fresh water having passed through the first condenser module 441 from flowing in the direction of the main flow path 410, A second condenser module 442 or a second condenser module 442 to prevent the fresh water supplied to flow to the engine scavenge cooling unit 450 or to cool the dumping steam in the second condenser module 442 from flowing in the direction of the first condenser module 441 or the engine scavenge cooling unit 450 Direction control valve It comprises 444.

In this embodiment, the first directional control valve 443 and the second directional control valve 444 may be three-way valves.

Hereinafter, the operation state of the dumping condenser unit 440 will be briefly described as operation or non-operation of the medium / low-temperature waste heat recovery system 100. [

The cooling water supplied from the main flow path 410 flows through the first direction control valve 443, the first condenser module 441, the second direction control valve 444, And is supplied to the evaporator 110 of the medium-low-temperature waste heat recovery system 100 via the engine scavenging unit 450.

At this time, the first directional control valve 443 can flow the cooling water only to the first condenser module 441, and the second directional control valve 444 can flow the cooling water to the engine scavenging unit 450 only.

The cooling water does not flow in the direction of the dumping condenser unit 440, so that the steam supplied to the first dumping condenser module is directly supplied to the second condenser module 442 without heat exchange with the cooling water. do. In this case, condensation of the damping steam may be effected by fresh water supplied to the second condenser module 442.

The primary condensation of the dumping steam in the first condenser module 441 is caused by fresh water supplied to the first condenser module 441 by the second directional control valve 444 and the first directional control valve 443 It is possible. That is, a line connected to the second condenser module 442 and connected to the second directional control valve 444 and connected to the fresh water flowing line is connected to the first directional control valve 444, A part of the fresh water flowing into the second condenser module 442 is connected to the first condenser module 441 through the second directional control valve 444, Can be discharged via the first directional control valve 443 through a line connected to the second condenser module 442.

The engine scavenge cooling unit 450 heat-exchanges the cooling water whose temperature has been increased in the dumping condenser unit 440 with the scavenging air supplied from the turbocharger TC of the engine E, Thereby further increasing the temperature of the delivered cooling water and cooling the heat exchanged desired air.

That is, in the present embodiment, the temperature of the heat source, which is transmitted to the evaporator 110, is further increased by further increasing the temperature of the heat source transmitted to the evaporator 110 of the low-temperature on-off heat recovery system 100 by the engine desire cooling unit 450 106 < [deg.] ≫ C so that the efficiency of the medium-low-temperature waste heat recovery system 100 can be improved.

In the present embodiment, as shown in Fig. 1, the engine scavenge cooling unit 450 exchanges heat between the cooling water whose temperature is raised through the dumping condenser unit 440 and the scavenging air supplied from the turbocharger TC, A second stage module 452 for cooling the desired air that has passed through the first stage module 451 and a second stage module 452 for cooling the rear line and the front line of the first stage module 451, And a third direction control valve 453 for preventing dry runing of the first stage module 451 by supplying fresh water to the first stage module 451 when the low-temperature on-off heat recovery system 100 is not operated, (453) and a fourth directional control valve (454).

In this embodiment, the third directional control valve 453 and the fourth directional control valve 454 may be three-way valves.

Hereinafter, the operation state of the engine scavenge cooling unit 450 will be briefly described as operating or non-operating the medium / low-temperature waste heat recovery system 100.

The cooling water supplied from the first condenser module 441 flows through the third directional control valve 453, the first stage module 451 and the fourth directional control valve 454 And is supplied to the evaporator 110 of the low-temperature on-site heat recovery system 100.

At this time, the third directional control valve 453 may flow only the first stage module 451, and the fourth directional control valve 454 may flow the cooling water only to the evaporator 110.

When the low-temperature on-the-fly heat recovery system 100 is not operated, cooling water does not flow to the first stage module 451, and therefore the first stage module 451 is driven by the high temperature scavenging Running may occur.

The temperature of the stagnated cooling water in the first stage module 451 of the engine scavenge cooling unit 450 is continuously raised by the high temperature compressed scavenge air supplied through the supercharger TC to exceed the boiling point, So that the pressure of the line can be raised.

Of course, a safety valve (not shown) for discharging the pressure is provided so that the pressure is not raised above a certain pressure, but it is not desirable if a safety valve designed to operate in an emergency is operated from time to time.

In addition, since the pneumatic air is not cooled by the first stage module 451 of the engine pneumatic cooling unit 450, it may impose a burden on the second stage module 452 for cooling the pneumatic air, Cooling may not be performed as desired, which may affect engine performance.

The present embodiment can prevent the dry running of the fresh water first stage module 451 supplied to the first stage module 451 by the third directional control valve 453 and the fourth directional control valve 454 . That is, a line connected to the second stage module 452 and connected to the fourth directional control valve 454 through which fresh water flows is connected to the second stage module 452, A part of the fresh water flowing into the second stage module 452 is connected to the first stage module 453 through the fourth directional control valve 454 and is discharged from the first stage module 451 Can be discharged via the third directional control valve 453 through the line connected to the second stage module 452.

The cooling water circulating system 400 according to the present embodiment is configured such that the cooling water discharged from the engine E is not supplied to the dumping condenser unit 440 but bypasses the low- A control valve 470 provided on the bypass line 460 for supplying the coolant to the jacket cooler 420 and a temperature sensor 480 provided on the main line on the downstream side of the jacket cooler 420.

In this embodiment, the temperature sensor 480 is provided in the main flow path 410 at the rear end of the jacket cooler 420 and the temperature of the point is excessively raised, that is, The control valve 470 may be opened to allow the cooling water to flow through the bypass line 460 when the temperature of the cooling water is not absorbed through the bypass line 450.

The exhaust gas recirculation system 500 recirculates the exhaust gas discharged from the engine E when the ship according to the present embodiment runs an ECA (Emission Control Area), and the recirculated exhaust gas is supplied from the turbocharger TC And is supplied to the engine E together with the scavenging to reduce the generation of NOx.

Specifically, most of the NOx is generated when the combustion is performed at a high temperature in the combustion chamber of the engine (E). In general, as the concentration of oxygen increases, the combustion temperature also increases. That is, since the concentration of oxygen is proportional to the combustion temperature, if the concentration of oxygen supplied to the combustion chamber can be reduced, the production of NOx can be reduced as a result. This has a beneficial effect in terms of the regulation on IMO Tier III (NOx emissions), which will be applied from 2016, ie, the response to regulations requiring reduction of NOx emissions to the level required when operating ECA.

In the present embodiment, the exhaust gas recirculation system 500 mixes some of the exhaust gas that is combusted in the engine E with little oxygen and the scavenging gas supplied from the turbocharger TC to supply it to the engine E, The concentration is lowered and the generation of NOx is reduced due to the decrease of the combustion temperature.

1, the exhaust gas recirculation system 500 includes a scrubber (not shown) for removing impurities contained in the hot exhaust gas discharged from the engine E, A cooler 520 for cooling the high temperature exhaust gas from which the impurities have been removed from the scrubber 510 and an exhaust gas cooled by the cooler 520 is supplied from the turbocharger TC to the engine E A blower 530 blowing a cooled exhaust gas so as to be supplied to the engine E by being mixed with the exhaust gas from the turbocharger TC and a line for guiding the exhaust gas discharged from the turbocharger TC to the scrubber 510, And a second on-off valve 550 provided on a line for guiding the exhaust gas discharged from the blower 530 to the engine E to open and close the line.

In the present embodiment, the exhaust gas recirculation system 500 can be driven only when the ECA is operated by the first on-off valve 540 and the second on-off valve 550, which will be described later, .

In this embodiment, the cooling water can be cooled by cooling water at a low temperature. The heat of exhaust gas discharged from the cooler 520 and the water circulated in the waste heat recovery system 200 are exchanged with each other to control the temperature of the condensed water supplied to the heat exchanger 280 It is possible to manufacture the cooler 520 in two stages.

1, the cooler 520 primarily exchanges heat between the exhaust gas discharged from the scrubber 510 and the condensed water circulated in the waste heat recovery system 200 to cool the exhaust gas first A first cooler 521 for raising the temperature of the discharged condensed water together with the exhaust gas and the condensed water discharged from the first cooler 521 and a second cooler 522).

The present embodiment has the advantage that the flow rate of the cooling water supplied to the cooler 520 can be reduced in addition to the advantages described above, so that the power consumption can be further reduced as the flow rate decreases.

The first on-off valve 540 and the second on-off valve 550 minimize the occurrence of NOx when the ship according to the present embodiment is operated in an emission control area (ECA) in which exhaust of exhaust gas containing NOx is limited The exhaust gas is supplied to the exhaust gas recirculation system 500 and the exhaust gas is supplied to the waste heat recovery system 200 when the ship is operated in an area other than the ECA so as to reduce the energy used in the ship do.

That is, when the ship according to the present embodiment operates the ECA, all or a part of the exhaust gas discharged through the turbocharger TC is opened to the scrubber 510 by opening the first opening / closing valve 540. The exhaust gas flowing through the cooler 520 and the blower 530 flows into the engine E together with air supplied from the turbocharger TC by opening the second on-off valve 550.

In this embodiment, the first on-off valve 540 and the second on-off valve 550 may be a proportional control valve controlled by an electrical signal.

In this embodiment, as shown in FIG. 1, the above-described engine scavenging unit 450 may further be provided between the cooler 520 and the heat exchanger 280.

In this case, the air to be purged is high in temperature of about 200 DEG C, so that the water supply can be heated by the engine scavenging unit 450 prior to the heat exchanger 280, so that the load of the heat exchanger 280 can be reduced. Further, there is an advantage that the water supply can be additionally heated in advance regardless of whether the low-temperature on-site waste heat recovery system 100 is operated or not.

Hereinafter, an operation state diagram of this embodiment will be briefly described with reference to FIG. 1, wherein the water supply of the waste heat recovery system is supplied via the condenser 140 of the medium / low-temperature waste heat recovery system 100.

The organic refrigerant flowing into the condenser 140 of the medium-low-temperature waste heat recovery system 100 needs condensation in the condenser 140 when the low-temperature on-site waste heat recovery system 100 and the waste heat recovery system 200 are in operation, 1 is a schematic view showing a state in which water is supplied to a condenser 140 from a waste heat recovery system 200 through a water supply heat exchange unit 300 as shown in FIG. 1 without supplying fresh water as a condensation heat source of organic refrigerant, Can be condensed.

That is, since the heat of the organic refrigerant, which is conventionally discharged from the condenser, can be used as the heat source for heating the water supplied through the water supply heat exchanging unit 300, energy can be saved by maximizing the waste heat recovery.

If the organic refrigerant is not sufficiently cooled due to the insufficient cooling capacity of the water supplied from the water feed heat exchanging unit 300, the efficiency of the medium and low-temperature waste heat recovery system 100 may be lowered or equipment problems may occur.

In order to prevent such a problem, in this embodiment, a separate line through which fresh water flows at about 36 degrees is provided in the condenser 140, and the cooling capacity of the water supply is supplemented by exchanging the fresh water supplied through the separate line with the organic refrigerant The stability of the system can be enhanced.

On the other hand, when the low-temperature on-site heat recovery system 100 is not operated, waste heat can not be obtained from the condenser 140. Therefore, the water supplied from the heat exchanger feedwater pump 270 bypasses the condenser 140, 280).

FIG. 2 is a view schematically showing an energy saving device for a ship using waste heat of organic refrigerant according to a second embodiment of the present invention.

The energy saving device 1a of the ship using the waste heat of the organic refrigerant according to the present embodiment further includes a condensate heater 490 in the cooling water circulation system 400 ' And differs from the first embodiment in that heat exchange is performed between the cooling water and the water in the waste heat recovery system 200.

In the case of the cooling water heat exchanger 490, the waste heat is lost on the side of the low-temperature on-site waste heat recovery system 100, but is advantageously applicable as an option on the waste heat recovery system 200. Since the efficiency of the waste heat recovery system 200 is higher than the efficiency of the waste heat recovery system 200, it is possible to increase the waste heat recovery efficiency in the entire system by increasing the waste heat recovery source in the waste heat recovery system 200.

3 is a schematic view illustrating an energy saving device for a ship using waste heat of organic refrigerant according to a third embodiment of the present invention.

The energy saving device 1b of the ship using the waste heat of the organic refrigerant according to the present embodiment is different from the above-described embodiments in that the engine scavenging unit 450 is provided at the front end of the cooler 520. [

3, a cooling water heat exchanger 490 is provided in the cooling water circulation system 400. However, the cooling water heat exchanger 490 may not be provided as shown in FIG.

As described above, according to the present embodiment, the water supplied to the heat exchanger for driving the steam turbine of the waste heat recovery system can be heat-exchanged with the organic refrigerant in the condenser of the medium-low-temperature waste heat recovery system to maximize the recovery of waste heat, .

Also, when a plurality of engines are provided, the scavenge air waste heat generated in each engine can be used in the waste heat recovery system, thereby maximizing the waste heat recovery.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

1,1a, 1b: Ship energy saving device 100: Low-temperature on-site heat recovery system
110: Evaporator 120: Turbine
130: generator 140: condenser
150: Pump 160: Pipeline
200: waste heat recovery system 210: gas turbine
220: steam turbine 230: condenser
240: Feed water pump 250: Control valve
260: vacuum degassing unit 270: heat exchanger feed pump
280: heat exchanger 290: steam separator
300: water heat exchanger 310: branch line
320: Directional control valve 400, 400 ': Coolant circulation system
410: Main flow path 420: Jacket cooler
430: cooling water pump 440: dumping condenser unit
450: engine scavenging unit 460: bypass line
470: Control valve 480: Temperature sensor
490: Cooling water heat exchanger 500: Exhaust gas recirculation system
510: scrubber 520: cooler
530: blower 540: first opening / closing valve
550: Second open / close valve E: Engine
T: Water tank TC: Supercharger

Claims (9)

A medium and low temperature waste heat recovery system operating with an organic refrigerant having a lower boiling point than water as a working fluid;
A waste heat recovery system in which water supplied from a plurality of engines provided in a ship to a heat exchanger for driving the steam turbine is used for heat exchange with a condenser of the medium and low-temperature waste heat recovery system using the exhaust gas discharged from a plurality of engines as a working fluid, ;
An exhaust gas recirculation system for recirculating a part of the exhaust gas to supply the exhaust gas to the plurality of engines while exchanging heat between the exhaust gas and the feed water at a front end of the heat exchanger; And
And an engine scavenging unit for exchanging scavenge air waste heat with the feed water from the front end of the heat exchanger. The method according to claim 1,
Wherein the engine scavenging unit further heats the water to be heat-exchanged and discharged in the exhaust gas recirculation system. The method according to claim 1,
Wherein the engine scavenging unit heats the feed water flowing into the exhaust gas recirculation system prior to the exhaust gas recirculation system. The method according to claim 1,
The exhaust gas recirculation system comprises:
A scrubber for removing impurities contained in the exhaust gas discharged from the plurality of engines;
A cooler for cooling the exhaust gas supplied from the scrubber; And
And a blower for blowing the exhaust gas cooled by the cooler to the plurality of engines by being mixed with the scavengers supplied from the supercharger and flowing into the engine. The method of claim 4,
The cooler includes:
A first cooler for primarily exchanging heat between the exhaust gas discharged from the scrubber and water circulated in the waste heat recovery system to exhaust the exhaust gas; And
And a second cooler for mutually exchanging heat between the exhaust gas discharged from the first cooler and a liquid separate from the supply water to thereby secondarily cool the exhaust gas. The method according to claim 1,
Further comprising a water supply heat exchanging unit for connecting the low-temperature on-site heat recovery system and the waste heat recovery system to heat exchange with each other,
The water supply heat-
A branch line branching from a front end line of the heat exchanger and returning to the front end line after passing through the condenser; And
And a directional control valve provided at an intersection of the branch line and the leading line to bypass the condenser or the condenser and supply the water to the heat exchanger. The method according to claim 1,
Further comprising a main flow passage through which cooling water for cooling the engine flows, and a cooling water circulation system for supplying waste heat of the cooling water to an evaporator of the low-temperature on-site waste heat recovery system. The method of claim 7,
Wherein the cooling water circulation system further comprises a cooling water heat exchanger for exchanging heat between cooling water flowing through the main flow path and feed water flowing into the exhaust gas recirculation system. The method according to claim 1,
The engine is a main engine,
Wherein the vessel uses waste heat of an organic refrigerant including a container line.

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