KR101403622B1 - Waste heat recovery system for ship that can remove dissolved oxygen by minimizing steam consumption - Google Patents

Abstract

Disclosed is a waste heat recovery system for a ship capable of removing dissolved oxygen without consuming steam. A waste heat recovery system of a ship according to the present invention is a waste heat recovery system for generating electric power by using exhaust gas discharged from an engine of a ship as a working fluid. The waste heat recovery system comprises a water supply channel provided in the waste heat recovery system, And a vacuum degassing portion for removing the dissolved oxygen present in the vacuum without using steam.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste heat recovery system for a ship capable of removing dissolved oxygen without consuming steam.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste heat recovery system for a ship capable of removing dissolved oxygen without consuming steam and more particularly to a waste heat recovery system for recovering dissolved oxygen present in a feed water which is a major cause of heat exchanger or steam equipment corrosion To a waste heat recovery system for a ship which can be removed without consuming steam.

There have been researches on a system that improves the efficiency of ship propulsion and saves the energy of the ship as a whole. Normally, only a part of the fuel of the main engine is used as energy for propulsion of the ship, and the rest is discharged to the atmosphere in the form of waste gas. Accordingly, a waste heat recovery system, which collects the waste gas from the main engine and utilizes it as the driving force of the engine or as another energy source, is attracting attention.

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 can be recovered and recycled as useful energy, the fuel can be saved by that much, which can contribute to the reduction of the total energy consumed by the ship.

As a result, in recent years, there has been a need for a highly efficient ship or an eco-friendly vessel capable of saving energy by recovering a part of the waste heat discharged to the outside, (Or a power turbine) used as a direct working fluid and a steam turbine using a part of the steam generated by using heat of a high temperature exhaust gas as a working fluid to produce electric power, Waste Heat Recovery System (WHRS) is applied.

1 is a schematic view of a waste heat recovery system according to an embodiment of the prior art.

As shown in FIG. 1, in an embodiment of the prior art, a steam turbine (ST (steam turbine) ST (steam turbine)) is driven by steam generated by exchanging heat between hot exhaust gas discharged from the engine E and water supplied to a heat exchanger To generate electric power or to drive the gas turbine GT with the exhaust gas discharged from the engine E to produce electric power.

The steam turbine (ST) produces power by using the steam generated from the heat exchanger (HE) as a driving force, and thus the ability to produce electric power according to the amount of steam is determined.

Meanwhile, the conventional waste heat recovery system supplies steam generated in the heat exchanger (HE) to the water supply tank, as shown in FIG. 1, in order to prevent corrosion of the heat exchanger (HE) and the steam equipment.

This is to remove the dissolved oxygen present in the feed water, which is the main cause of heat exchanger (HE) and steam facility corrosion. That is, since the amount of dissolved oxygen present in the feed water is inversely proportional to the temperature of the feed water, when the high-temperature steam generated in the heat exchanger HE is supplied to the feed water tank, the amount of dissolved oxygen in the feed water is reduced due to a rise in the feed water temperature. As a result, it plays a role of retarding the corrosion of the heat exchanger (HE) and the like.

However, if the steam generated in the heat exchanger (HE) is supplied to the water supply tank for removing dissolved oxygen, the amount of steam supplied to the steam turbine (ST) is reduced. Thus, the power efficiency of the steam turbine .

Therefore, it is required to develop a new waste heat recovery system that can efficiently generate electricity while preventing corrosion in heat exchangers and steam plants.

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. 2010-0067247 (Daewoo Shipbuilding & Marine Engineering) 2010. 06. 21.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a waste heat recovery system for a ship that can remove dissolved oxygen without the use of steam in a heat exchanger and a steam facility to prevent corrosion and efficiently generate electric power.

According to an aspect of the present invention, there is provided a waste heat recovery system for generating electric power by using exhaust gas discharged from an engine of a ship as a working fluid, the waste heat recovery system comprising: a waste heat recovery system provided in a water supply channel of the waste heat recovery system, A waste heat recovery system for a ship including a vacuum degassing portion for removing dissolved oxygen without using steam can be provided.

The vacuum degassing unit may be a vacuum degassing tank that is maintained in a vacuum state and removes dissolved oxygen present in the supplied water by vacuum pressure.

And a vacuum condenser for condensing the generated steam based on the exhaust gas into a vacuum, wherein the dissolved oxygen removed from the vacuum degassing part can be supplied to the vacuum condenser.

And an orifice provided on a line connecting the vacuum degassing unit and the vacuum condenser to maintain a vacuum pressure of the vacuum degassing unit.

And a heat exchanger for mutually exchanging heat between the exhaust gas and the water from which the dissolved oxygen is removed from the vacuum degassing part, wherein the water supplied from the vacuum degassing unit to the heat exchanger is heat-exchanged with the waste heat of the engine jacket cooling water, To the heat exchanger.

The engine cooler may further include an engine scavenger cooler for exchanging heat with the scavenging water supplied from the supercharger to raise the temperature of the water supply before the scavenged water is heat-exchanged with the waste heat of the engine jacket cooling water and supplied to the heat exchanger.

Wherein the engine scavenger cooler further comprises: a first scavenger cooler for exchanging heat between the increased temperature water and the scavenging water supplied from the supercharger to further raise the temperature of the water with the increased temperature; And a second scavenger cooler for exchanging heat between the scavenging and low-temperature cooling water cooled by the first scavenging cooler to cool the scavenger.

According to another embodiment of the present invention, the exhaust gas discharged from the engine of the ship is used as a working fluid to produce electric power, and the dissolved oxygen present in the water to be heat-exchanged with the exhaust gas is removed by vacuum without using steam. The waste heat recovery system of FIG.

Dissolved oxygen present in the feedwater can be removed from the vacuum degassing tank where the interior remains in a vacuum.

The temperature of the water to be heat-exchanged with the exhaust gas may be increased by heat exchange with the waste heat of the engine jacket cooling water before heat exchange with the exhaust gas.

Embodiments of the present invention are capable of removing dissolved oxygen with vacuum pressure in a heat exchanger and steam facility without steam to prevent corrosion without consuming the steam generated in the heat exchanger and to consume steam to prevent corrosion It is possible to improve the power efficiency compared to the same exhaust gas waste heat source.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a waste heat recovery system of a ship in an embodiment of the prior art; FIG.
2 is a schematic view of a waste heat recovery system for a ship capable of removing dissolved oxygen without consuming steam according to an 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.

2 is a schematic view of a waste heat recovery system for a ship capable of removing dissolved oxygen without consuming steam according to an embodiment of the present invention.

As shown in this figure, a waste heat recovery system 1 for a ship capable of removing dissolved oxygen without consuming steam according to the present embodiment is directly driven by exhaust gas discharged from the engine E, A steam turbine 10 interlocked with the gas turbine 10 and providing a driving force for rotating the generator 20 by steam provided in a heat exchanger 100 to be described later, A condenser 40 for condensing steam discharged from the steam turbine 30; a water supply pump 50 for pumping condensed water in the condenser 40; (V) provided in the water supply line to open and close the water supply line so that the water is circulated to the condenser (40), a vacuum degassing unit (50) for removing the dissolved oxygen present in the water supplied from the water supply pump (60).

1, the waste heat recovery system 1 is provided in a line connecting the vacuum degassing unit 60 and the condenser 40 so that water is supplied from the vacuum degassing unit 60 to the condenser 40 An orifice 70 that maintains an appropriate differential pressure so as not to be passed to the vacuum degassing unit 60 and a heat exchanger feedwater pump 80 that pumps the water from which the dissolved oxygen has been removed in the vacuum degassing unit 60 to an engine scavenger cooler 90 An engine scavenger cooler 90 for exchanging heat between the water supplied from the heat exchanger feed pump 80 and the scavenger supplied from the turbocharger TC to the engine E, A heat exchanger 100 for exchanging heat with the exhaust gas discharged from the steam generator E to generate steam for driving the steam turbine 30 and a steam separator for separating steam and water from the steam generated in the heat exchanger 100 110).

The vacuum degassing unit 60 may be a vacuum degassing tank 60 that is kept in a vacuum state and removes dissolved oxygen present in the supplied water by vacuum pressure.

Hereinafter, the principle of removing dissolved oxygen present in the feed water from the vacuum degassing tank 60 will be briefly described.

In the present embodiment, the vacuum pressure inside the vacuum degassing tank 60 may be approximately 700 mmHg vacuum pressure. Dissolved oxygen present in the feed water supplied to the vacuum degassing tank 60 can be removed at a low temperature by lowering the pressure not the temperature rise.

Specifically, according to Henry's law, the lower the pressure, the smaller the amount of gas that can be dissolved in the liquid. Therefore, in the vacuum pressure inside the vacuum degassing tank (60), oxygen Is less than the atmospheric pressure.

Accordingly, when the inner pressure of the vacuum degassing tank 60 is lowered to the vacuum pressure, the solubility of oxygen is reduced so that the oxygen is separated from the feed water in the form of gas, so that dissolved oxygen existing in the feed water can be removed.

On the other hand, the oxygen removed from the vacuum degassing tank (60) is supplied to the condenser (40) and discharged from the condenser (40). The orifice 70 described above is provided on the line connecting the vacuum degassing tank 60 and the condenser 40. The orifice 70 maintains a proper differential pressure so as to maintain the vacuum pressure of the vacuum degassing tank 60 so that water does not flow to the condenser 40 in the vacuum degassing tank 60.

The engine scavenger cooler 90 functions to heat the feed water supplied to the heat exchanger 100 from the scavenging unit TC to raise the temperature of the feed water and cool the scavenging unit.

In this embodiment, the engine scavenger cooler 90 may be provided in two stages so as to cool the scavengers even with low-temperature cooling water. 2, the engine scavenger cooler 90 exchanges heat between the water supplied from the heat exchanger feed pump 80 and the scav. Air supplied from the turbocharger TC to cool the scavenger A first scavenging cooler 91 for raising the temperature of the water supplied to the heat exchanger 100 at the same time as the scavenging operation and a cold fw supplied externally to the scavenging unit, And a second scavenger cooler 92 for performing second heat exchange with the second scavenger cooler 92.

In this embodiment, the condenser 40 may be a vacuum condenser, and the heat exchanger 100 may be provided in multiple stages in order to improve heat exchange efficiency. T is a water supply tank (T) for supplying water to the vacuum degassing unit (60).

On the other hand, when the temperature of the feed water supplied to the heat exchanger 100 is too low (the temperature varies depending on the vacuum pressure of the condenser, considering the pressure of the currently applied condenser 40), it may be about 30 to 40 ° C. The amount of waste heat required to generate the steam in the heat exchanger 100 is more required.

That is, waste heat of exhaust gas is required to generate the same amount of steam, and the amount of steam generated in the waste heat source of the same exhaust gas is inevitably reduced. As a result, since the amount of steam usable in the steam turbine 30 is reduced, it can be considered that simply applying the vacuum degassing tank 60 does not have a great advantage in terms of efficiency of the waste heat recovery system.

Therefore, as shown in Fig. 2, the waste heat discharged from the engine jacket system 200 used for cooling the engine E is used to control the temperature of the water supplied to the heat exchanger 100 to the engine subcooler 90 So that the amount of waste heat of the exhaust gas required for generating the same steam in the heat exchanger 100 can be made equal.

In the present embodiment, the engine jacket system 200 circulates the heat source as cooling water to cool the engine E, and as shown in Fig. 2, the engine jacket 210 and the engine jacket 210 An engine jacket heat exchanger 220 for mutually exchanging heat between the number of jackets whose temperature has been increased and the temperature of which is increased and the water to be pumped by the heat exchanger feed pump 80 and an engine 220 for cooling the cooling water supplied from the engine jacket heat exchanger 220, A jacket cooler 230 and an engine jacket pump 240 for pumping cooling water, which is a heat source cooled by the engine jacket cooler 230, to the engine jacket 210.

Hereinafter, an operation state of the waste heat recovery system 1 of a ship capable of removing dissolved oxygen without consumption of steam according to the present embodiment will be briefly described with reference to FIG.

First, the exhaust gas discharged from the engine E is supplied to the heat exchanger 100 via the turbocharger TC or supplied to the gas turbine 10 to drive the gas turbine 10. The exhaust gas supplied to the heat exchanger 100 is heat-exchanged with the water supplied to the heat exchanger 100 to convert the supplied water into steam.

The phase-converted steam is separated into steam and water in the steam separator 110, and the separated steam is supplied to the steam turbine 30 and used as a drive power source for the steam turbine 30. [ The steam discharged from the steam turbine 30 is condensed in the condenser 40 to be phase-converted into a liquid water in the liquid state. The phase-changed water is supplied to the vacuum degassing unit 60 or the condenser 40).

Dissolved oxygen existing in the water supplied to the vacuum degassing unit 60 is removed by the vacuum pressure inside the vacuum degassing unit 60 and supplied to the condenser 40. The dissolved water is removed from the water in the heat exchanger Is pumped by the pump (80) and supplied to the engine scavenger cooler (90).

The water pumped by the heat exchanger feed pump 80 is firstly warmed up by heat exchange with the waste heat of the engine jacket system 200 before being supplied to the engine coolant cooler 90, The heat is exchanged with the scavenging air supplied from the turbocharger TC at the first scavenger cooler 91 of the scavenging unit 90, and the temperature is secondarily raised.

Secondarily, the water whose temperature has risen is heat-exchanged with the exhaust gas in the heat exchanger 100 and is phase-converted into steam, which is separated into steam and water in the steam separator 110, and the separated steam is discharged into the steam turbine 30 And the above-described process is repeated.

Since the water supplied to the heat exchanger 100 is heat-exchanged in advance in the engine jacket system 200 and the engine scavenger cooler 90, the amount of the exhaust gas, which is a heat source required for phase-converting the water into steam, can be reduced have.

In addition, the water supplied to the heat exchanger 100 can prevent and delay the generation of corrosion in the heat exchanger 100 because dissolved oxygen is previously removed in the vacuum degassing unit 60.

As described above, according to this embodiment, dissolved oxygen can be removed from the heat exchanger and the steam facility by using vacuum pressure without steam, so that corrosion can be prevented without consuming the steam generated in the heat exchanger, There is an advantage that the power efficiency can be improved compared to the same exhaust gas waste heat source.

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: Ship's heat recovery system that can remove dissolved oxygen without consuming steam
10: gas turbine 20: generator
30: steam turbine 40: condenser
50: Feed water pump 60: Vacuum degassing part (vacuum degassing tank)
70: Orifice 80: Heat exchanger feed pump
90: engine scavenger cooler 100: heat exchanger
110: steam separator 200: engine jacket system
210: engine jacket 220: engine jacket heat exchanger
230: Engine jacket cooler 240: Engine jacket pump
E: Engine T: Water tank
TC: supercharger V: opening / closing valve

Claims (10)

CLAIMS 1. A waste heat recovery system for generating electric power by using an exhaust gas discharged from an engine (E) of a ship as a working fluid,
A vacuum degassing unit 60 provided in the water supply channel of the waste heat recovery system to remove dissolved oxygen present in the water supplied through the water supply channel by vacuum without using steam;
A heat exchanger (100) for exchanging heat between the exhaust gas and the water from which the dissolved oxygen is removed from the vacuum degassing unit (60);
A steam turbine (30) for providing a driving force for rotating the generator (20) by steam supplied from the heat exchanger (100); And
And a gas turbine (10) that is driven by an exhaust gas discharged from the engine (E) to provide driving force for rotating the generator (20) and interlocked with the steam turbine (30)
The water supplied from the vacuum degassing unit 60 to the heat exchanger 100 is heat-exchanged with the waste heat of the engine jacket cooling water and is supplied to the heat exchanger 100 in a state where the temperature is raised.
A first scavenging cooler 91 for exchanging heat between the water in which heat is exchanged with the waste heat of the engine jacket cooling water and the scavenging water supplied from the overcharging (TC) Further comprising an engine scavenger cooler (90) having a second scavenging cooler (92) for exchanging heat between the scavenging and low-temperature cooling water cooled by the first scavenging cooler (91) to cool the scavenging unit. The method according to claim 1,
Wherein the vacuum degassing unit (60) is a vacuum degassing tank that is maintained in a vacuum state and removes dissolved oxygen present in the supplied water by vacuum pressure. The method according to claim 1,
Further comprising a condenser (40) for condensing the generated steam based on the exhaust gas to a vacuum,
And the dissolved oxygen removed from the vacuum degassing unit (60) is supplied to the condenser (40). The method of claim 3,
Further comprising an orifice (70) provided in a line connecting the vacuum degassing unit (60) and the condenser (40) to maintain a vacuum pressure of the vacuum degassing unit (60). The method according to claim 1,
And a water supply tank (T) for supplying water to the vacuum degassing unit (60). delete delete delete delete delete

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