KR20140085001A - Energy saving system for using waste heat of ship - Google Patents

Abstract

An energy saving system using waste heat of a ship is disclosed. The energy saving system using waste heat of a ship of the present invention comprises a waste heat recovery steam generating unit which generates wet steam by heating liquid supplied to an exhaust gas economizer after recovering waste heat of exhaust gas supplied to the exhaust gas economizer; and an organic rankin cycle generator generating electricity using, as working fluid, an organic refrigerant having a boiling point lower than that of water and heat-exchanged with liquid separated from the wet steam. The steam is supplied to the organic rankin cycle generator and is heat-exchanged with the organic rankin cycle generator.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an energy saving system using waste heat of a ship, and more particularly, to a system and method for operating an organic Rankine cycle power generation apparatus using waste heat of an exhaust gas economizer and using an organic refrigerant having a boiling point lower than water as a working fluid To an energy saving system using waste heat of a ship.

As global warming has increased its impact on the environment, major countries around the world are actively responding to climate change by setting national targets for greenhouse gas reduction. In particular, the International Maritime Organization (IMO) is developing legislative measures to reduce greenhouse gas emissions from ships and will apply the requirements to limit the EEDI (Energy Efficiency Design Index).

Therefore, it is necessary to study the energy efficiency of ship and it is actively studied in various fields to utilize the energy that is abandoned from the ship. Recently, a waste heat recovery system (WHRS) utilizing a heat source of exhaust gas has been developed and utilized.

The waste heat recovery system includes a gas turbine (or a power turbine) that uses a high-temperature exhaust gas discharged from an engine as a direct working fluid, and a steam that uses a part of the steam generated by the heat of the high-temperature exhaust gas as a working fluid Turbines, etc., to generate electricity.

However, the gas turbine and the steam turbine of the waste heat recovery system can recover heat only from a heat source of about 200 to 250 ° C or more, and heat of a lower temperature is still inevitable to be discarded.

Therefore, in order to increase the energy utilization, an additional system capable of recovering waste heat must be constructed. The existing WHRS (Wast Heat Recovery System) uses water as the working fluid and has a disadvantage in that it can not recover the waste heat at a low temperature due to the high boiling point of water. When the exhaust gas is directly recovered and the turbine is operated, Although a large number of heat sources can be obtained, when the air is used as a working fluid, the efficiency of the turbine can be reduced by becoming wet steam at the turbine outlet.

This phenomenon can be solved by using ORC (Organic Rankin Cycle) system which can recover low and medium temperature thermal energy using organic refrigerant as a working fluid.

Since organic refrigerant has dT / ds ≥ 0, if organic refrigerant is used as the working fluid in the system, superheated steam is produced at the turbine outlet, and the flow in the turbine is always maintained in the dry steam. The stress applied can be reduced.

Also, because the organic refrigerant has a boiling point lower than that of steam, the waste heat of medium and low temperature can be recovered. Accordingly, the use of the organic landfill cycle together with the waste heat recovery system can increase the fuel consumption of the ship, resulting in a reduction in fuel cost and a reduction in CO ₂ emission. Therefore, a new improvement using the organic landfill cycle is required.

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 Laid-Open Publication No. 2012-0110709 (Korea Institute of Energy Research) Oct. 10,

Accordingly, it is an object of the present invention to provide an energy saving system using waste heat of a ship which can maximize the effect of collecting waste heat generated in an engine.

According to an aspect of the present invention, a waste heat recovery steam generator for recovering waste heat of an exhaust gas supplied to an exhaust gas economizer to heat a liquid supplied to the exhaust gas economizer to generate a wet steam; And an organic Rankine cycle generator for producing electricity by using an organic refrigerant having a boiling point lower than that of water as a working fluid, the steam being separated from the wet steam by heat exchange with the remaining liquid, and supplying the steam to the organic Rankine cycle generator The system for heat-exchanging heat with the organic Rankine cycle power generation apparatus can be provided.

Steam supplied to the organic Rankine cycle generator may not be used but steam may be discarded.

The waste heat recovery steam generator includes a first pump for supplying a liquid stored in a hot well to the exhaust gas economizer; A steam separator for separating the wet steam supplied from the exhaust gas economizer into steam and liquid; A second pump for pumping the liquid separated in the steam separator to the organic Rankine cycle generator; And a condenser for condensing the heat-exchanged fluid with the organic Rankine cycle generator.

The steam separated from the steam separator can be used for residence heating or fuel heating maintenance.

The organic Rankine cycle generator includes a first evaporator for separating steam from the humidified steam and exchanging heat with the remaining liquid to evaporate the organic refrigerant; A second evaporator for evaporating the organic refrigerant by exchanging heat between the organic refrigerant supplied from the first evaporator and steam supplied from the steam separator; A turbine rotating through the organic refrigerant evaporated by the second evaporator; A generator for generating electric power by interlocking with the rotation of the turbine; A condenser for cooling and liquefying the organic solvent from the turbine; A third pump for compressing and supplying the condensed organic solvent from the condenser to the evaporator; And a conduit for providing a circulation path of the organic refrigerant from the first evaporator to the third pump.

The turbine and the generator may be configured in multiple stages.

And a heat exchanger provided on a line connecting the first pump and the exhaust gas economizer to heat the liquid supplied to the exhaust gas economizer as a scavenging air heat source.

The heat exchanger may be provided in series with a line connecting the first pump and the exhaust gas economizer.

According to another aspect of the present invention, there is provided an exhaust gas recirculation apparatus for generating steam by heating a liquid supplied to an exhaust gas economizer using waste heat of an exhaust gas supplied to an exhaust gas economizer, A heat source and an organic coolant having a boiling point lower than that of water as a working fluid to heat the working fluid of the organic Rankine cycle power generation apparatus for generating electricity, supplying the steam to the organic Rankine cycle power generation apparatus, The energy saving system using the waste heat of the ship can be provided.

The embodiments of the present invention provide an organic Rankine cycle power generation apparatus using an organic refrigerant as a working fluid in a waste heat recovery steam generator using waste heat of an exhaust gas supplied to an exhaust gas economizer, wherein steam generated in the waste heat recovery steam generator The organic waste water is supplied to the organic Rankine cycle power generation unit and further heat exchanged to recover the waste heat of the exhaust gas more efficiently than when the conventional waste heat recovery steam generator is constructed.

1 is a schematic view illustrating an energy saving system using waste heat of a ship according to an embodiment of the present invention.
2 is an operational state diagram of an energy saving system using the waste heat of the ship shown in FIG.
3 is a schematic view illustrating an energy saving system using waste heat of a ship according to another 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 system using waste heat of a ship according to an embodiment of the present invention.

As shown in this figure, the energy saving system 1 using waste heat of a ship according to the present embodiment recovers the waste heat of the exhaust gas supplied to the exhaust gas economizer EE and supplies it to the exhaust gas economizer EE (100) which generates steam by heating the liquid to be heated, and an organic refrigerant having a boiling point lower than that of water as a working fluid to produce electricity. The steam generator And an organic Rankine cycle generator (200) for further heat exchange with the steam produced in the apparatus (100).

The waste heat recovery steam generator 100 recovers the waste heat of the exhaust gas discharged from the engine to generate heat by exchanging heat with the liquid in the exhaust gas economizer EE and supplies the generated steam to the in- It is a device for use for heating maintenance.

1, a waste heat recovery steam generator 100 according to the present embodiment includes a first pump 110 for supplying a liquid stored in a hot well (HW) to an exhaust gas economizer EE, A steam separator 120 for separating the wet steam supplied from the exhaust gas economizer EE into steam and liquid and a second pump 130 for pumping the separated liquid from the steam separator 120 to the organic Rankine cycle generator 200. [ And a condenser 140 for condensing the heat-exchanged fluid with the organic Rankine cycle generator 200.

In this embodiment, the fluid pumped by the first pump 110 is in a liquid state, but is heat-exchanged with the exhaust gas at a high temperature (200 DEG C or higher) supplied to the exhaust gas economizer EE while passing through the exhaust gas economizer EE, State, that is, water and steam are mixed.

The mixture of water and steam is supplied to the steam separator 120. The steam that is separated from the steam separator 120 can be used as a steam application unit (SU) to be used for residence heating or fuel heating maintenance through a pipe, And the steam that can not be used in the steam application station (SU) is supplied to the second evaporator 220 of the organic Rankine cycle generator 200, which will be described later.

The liquid separated from the steam separator 120 is pumped by the second pump 130 and supplied to the organic Rankine cycle generator 200. After the heat is exchanged in the first evaporator 210 and the organic Rankine cycle generator, 140 and stored in the hotwell (HW).

In this embodiment, the exhaust gas economizer (EE) includes an exhaust gas boiler as boiling steam or hot water with the exhaust gas of the engine, and the heat exchange inside the exhaust gas economizer (EE) can be multi-stage .

The organic Rankine cycle generator 200 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 also commonly referred to as an organic Rankine Cycle (ORC).

In this embodiment, since the organic Rankine cycle power generation apparatus 200 can use an organic refrigerant having a boiling point lower than that of water, for example, R 245fa, it can operate as a heat source at a lower temperature than the water supplied to the exhaust gas economizer (EE) Electric energy can be produced by using the waste heat of about 150 ℃ generated from ship.

In addition, in the present embodiment, the organic Rankine cycle power generation apparatus 200 is advantageous in that high efficiency can be obtained because heat exchange is performed in multiple stages using the heat source of steam as well as the heat source of the liquid separated from the steam separator 120.

1, the organic Rankine cycle power generation apparatus 200 separates steam from steam in the steam separator 120 and exchanges heat with the remaining liquid to generate organic refrigerant. A second evaporator 220 for evaporating the organic refrigerant by exchanging heat between the organic refrigerant supplied from the first evaporator 210 and the steam supplied from the steam separator 120, A turbine 230 rotating through the organic refrigerant evaporated by the evaporator 220, a generator 240 generating electricity by interlocking with the rotation of the turbine 230, A third pump 260 for compressing the condensed organic solvent from the condenser 250 and supplying the condensed organic solvent to the evaporator 250 and the third pump 260 from the first evaporator 210 to the third pump 260, And a conduit providing a circulation path of the organic refrigerant.

In this embodiment, the exhaust gas supplied from the engine has a temperature of about 200 ° C or more, but the temperature of the exhaust gas is lowered to about 160 ° C with heat exchange with the fluid of the waste heat recovery steam generator 100.

In this embodiment, the fluid (water) of the waste heat recovery steam generator 100 is heat-exchanged with exhaust gas at a pressure of 8 bar in the exhaust gas economizer EE, 1 evaporator 210 to transfer waste heat.

Further, the organic refrigerant, which is an operating oil of the organic Rankine cycle power generation apparatus 200, is first heat-exchanged with the liquid separated in the steam separator 120 in the first evaporator 210 to become a wet state vapor of 100 ° C or more, and the second evaporator 220 Exchanges heat with steam separated from the steam separator 120 and is supplied to the turbine 230 in a complete steam state.

The organic Rankine cycle power generation apparatus 200 is characterized in that as the temperature difference between the high temperature portion heated by the evaporator 210 and the low temperature portion cooled by the condenser 250 is larger, higher efficiency can be obtained as in the other turbine systems.

That is, the higher the temperature of the high temperature portion which is introduced into the evaporator 210 and transfers heat to the evaporator 210, the higher the efficiency of the temperature of the low temperature portion which absorbs the heat of the condenser 250 due to the flow thereof into the condenser 250.

Therefore, in this embodiment, since heat exchange is performed in two stages through the first evaporator 210 and the second evaporator 220, there is an advantage that a higher efficiency can be obtained than before.

The steam supplied to the second evaporator 220 can not be used in the steam application unit SU and is used in the steam supply unit SU as well as the steam supplied through the branch line SL Steam may be used.

Meanwhile, in this embodiment, the turbine 230 and the generator 240 may be provided in multiple stages.

2 is an operational state diagram of an energy saving system using the waste heat of the ship shown in FIG. Hereinafter, the operation state of the present embodiment will be briefly described with reference to FIG.

The exhaust gas discharged from the engine is heat-exchanged with the liquid supplied from the first pump 110 in the exhaust gas economizer EE to make the liquid supplied from the first pump 110 into a wet state in which steam and water are mixed, Is supplied to the steam separator (120).

The steam separator 120 separates the wet steam into steam and water. The steam, which is usable among the separated steam, is supplied to a steam application unit (SU) used for a residential district heating and the like. (HW). ≪ / RTI >

The liquid separated from the steam separator 120 is supplied to the first evaporator 210 of the organic Rankine cycle generator 200 through the second pump 130 and is first heat exchanged with the first evaporator 210, (140) and stored in the hotwell (HW).

Steam which can not be used in the steam use place (SU) among the steam separated by the steam separator 120 is supplied to the second evaporator 220 and is secondarily heat-exchanged with the organic refrigerant as the operating oil.

On the other hand, the organic refrigerant heat-exchanged in the first evaporator 210 is heated to a higher temperature in the second evaporator 220 and supplied to the turbine 230 to drive the turbine 230.

3 is a schematic view illustrating an energy saving system using waste heat of a ship according to a second embodiment of the present invention.

As shown in FIG. 3, the energy saving system 1a using the waste heat of the ship according to the present embodiment includes a heat exchanger 300 for recovering the desired heat of the engine, a first pump 110 and an exhaust gas economizer (EE) are connected in series to the line connecting the above-described embodiment.

If the heat exchanger 300 is provided in series as in the present embodiment, the heat exchanger 300 can be installed in the existing line. Therefore, the installation is simple, the line is simple, the pressure and the temperature can be easily controlled, So that there is an advantage in terms of cost.

Also, by increasing the temperature of the water supplied from the hotwell HW through the engine and the heat exchanger 300, the temperature of the water at the inlet of the exhaust gas economizer (EE) can be maintained at a stable temperature, And there is an advantage that water is supplied at a too low temperature during heat exchange in the economizer (EE), thereby preventing low-temperature corrosion in the system.

Further, by using a desired heat source of the engine, it is possible to increase the temperature of the water at a higher flow rate than that of the exhaust gas waste heat alone, and it is possible to transfer more heat energy to the organic Rankine cycle power generator 200 with an increase in flow rate.

On the other hand, the heat exchanger 300 may be connected in parallel to a line connecting the first pump 110 and the exhaust gas economizer EE.

As described above, according to the present embodiment, an organic Rankine cycle power generation apparatus using an organic refrigerant as a working fluid is constituted in a waste heat recovery steam generator using waste heat of an exhaust gas supplied to an exhaust gas economizer, and is generated in a waste heat recovery steam generator Steam is further supplied to the organic Rankine cycle generator and further heat exchanged to recover more waste heat of the exhaust gas than that of the conventional waste heat recovery steam generator, .

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: Energy saving system using waste heat of ship 100: Waste heat recovery steam generator
110: first pump 120: steam separator
130: second pump 140: condenser
200: Organic Rankine cycle generator 210: First evaporator
220: second evaporator 230: turbine
240: generator 250: condenser
260: third pump 300: heat exchanger
EE: Exhaust gas economizer HW: Hot Well
SL: Branch line SU: Steam application

Claims (9)

A waste heat recovery steam generator for recovering waste heat of the exhaust gas supplied to the exhaust gas economizer and heating the liquid supplied to the exhaust gas economizer to generate a wet steam; And
And an organic Rankine cycle generator for producing electricity by using an organic refrigerant whose boiling point is lower than that of water and which is heat-exchanged with the remaining liquid after the steam is separated from the wet steam,
Wherein the steam is supplied to the organic Rankine cycle generator and the heat is exchanged with the organic Rankine cycle generator. The method according to claim 1,
Wherein the steam supplied to the organic Rankine cycle power generation apparatus is steam that is not used but is discarded. The method according to claim 1,
The waste heat recovery steam generator comprises:
A first pump for supplying the liquid stored in the hot well to the exhaust gas economizer;
A steam separator for separating the wet steam supplied from the exhaust gas economizer into steam and liquid;
A second pump for pumping the liquid separated in the steam separator to the organic Rankine cycle generator; And
And a condenser for condensing the fluid heat-exchanged with the organic Rankine cycle generator. The method of claim 3,
Wherein the steam separated from the steam separator is used for residence heating or fuel heating maintenance. The method according to claim 1,
The organic Rankine cycle generator includes:
A first evaporator for separating steam from the humidified steam and exchanging heat with the remaining liquid to evaporate the organic refrigerant;
A second evaporator for evaporating the organic refrigerant by exchanging heat between the organic refrigerant supplied from the first evaporator and steam supplied from the steam separator;
A turbine rotating through the organic refrigerant evaporated by the second evaporator;
A generator for generating electric power by interlocking with the rotation of the turbine;
A condenser for cooling and liquefying the organic solvent from the turbine;
A third pump for compressing and supplying the condensed organic solvent from the condenser to the evaporator; And
And a conduit for providing a circulation path of the organic refrigerant from the first evaporator to the third pump. The method of claim 5,
Wherein the turbine and the generator are configured in multiple stages. The method of claim 2,
Further comprising a heat exchanger disposed in a line connecting the first pump and the exhaust gas economizer to heat a liquid supplied to the exhaust gas economizer as a scavenging air heat source. The method of claim 7,
Wherein the heat exchanger is provided in series with a line connecting the first pump and the exhaust gas economizer. A heat source of the liquid to be supplied to the hotwell after the steam is separated and a heat source of a liquid having a boiling point lower than that of the water are used as the exhaust gas economizer, Wherein the steam is supplied to the organic Rankine cycle power generator and further heat-exchanged with the working fluid, wherein the steam is supplied to the organic Rankine cycle power generator by operating the refrigerant as a working fluid to produce electricity. Energy saving system using waste heat.

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