KR102313221B1 - Apparatus and method for saving energy by using waste heat in exhaust gas scrubber and waste heat recovery device of ship - Google Patents

Abstract

The present invention relates to an in-ship energy saving device including an exhaust gas scrubber and a waste heat recovery device, and an energy recovery method using the same. Specifically, the fresh water in the exhaust gas scrubber through a first heat exchanger provides waste heat to the condensed water in the waste heat recovery device. There is an effect of reducing overall energy by transmitting the second heat exchanger, so that the fresh water circulation system in the exhaust gas scrubber can be stabilized, and a temperature sensor, a seawater valve, a frequency converter, etc. The temperature of the seawater used to cool can be efficiently controlled.

Description

Apparatus and method for saving energy by using waste heat in exhaust gas scrubber and waste heat recovery device of ship}

The present invention relates to an energy saving device in a ship including an exhaust gas scrubber and a waste heat recovery device, and an energy recovery method using the same. Specifically, the fresh water in the exhaust gas scrubber transfers waste heat to the condensed water in the waste heat recovery device, It relates to an energy saving device and an energy recovery method that are efficiently utilized.

About 50% of the heat energy generated when fuel is burned in a ship's propulsion or power generation engine is reused for propulsion or power generation, but most of the other heat is transferred to the outside of the ship through heat exchange in the form of exhaust gas or coolant. is emitted

This heat that cannot be reused and is thrown out of the ship is called waste heat. If some of this waste heat is recovered and used in a process that consumes fuel such as power generation, fuel can be saved that much, so that the overall energy consumed by the ship is reduced. It has a savings effect.

Recently, as the need for high-efficiency ships with energy-saving effects has increased, a gas turbine or power turbine that directly uses the high-temperature exhaust gas discharged from the engine as a working fluid has been additionally installed. A waste heat recovery system (WHRS) that can generate electricity is being applied.

Meanwhile, an issue that is becoming an international issue along with energy saving is the emission of sulfur oxides (SO _x ) and nitrogen oxides (NO _x ) generated from engine exhaust gas. Alternatively, regulations on the emission of nitric oxide are being applied, and the scope of the regulation is different depending on the region.

In particular, the emission of sulfur oxides is regulated as shown in the graph of Fig. 1 according to MARPOL ANNEX IV, and as of 2015, the global limitation area is regulated to 3.5% or less, and the SO _x Emission Control Area (ECA) is regulated to 0.1% or less. is becoming

When operating in a global limitation area, the regulated concentration of sulfur oxides is less than 3.5%, so this problem can be solved by simply using Low Sulfur Heavy Fuel Oil (LSHFO). Since the regulated concentration is very low at 0.1%, it is an exhaust gas scrubber that uses Low Sulfur Marine Gas Oil (LSMGO) containing less than 0.1% sulfur as fuel or removes sulfur oxides in the exhaust gas. (Exhaust Gas Scrubber) must be used.

In the early days, the exhaust gas scrubber was expensive to install and the size of the equipment was large, making it difficult to install in ships. However, as the number of ships operating sulfur oxide ECA increases, and the low productivity of LSMGO causes the price of LSMGO to rise, resulting in an excessive increase in the operating cost of the ship, the number of ships installing an exhaust gas scrubber is increasing.

On the other hand, a system to which such an exhaust gas scrubber is applied can be largely divided into three types as follows.

The first is an open loop system that directly sprays seawater to the scrubber as shown in FIG. 2 to remove sulfur oxides through alkali components contained in seawater. Since seawater is discharged overboard, it has a disadvantage that it cannot be applied in areas where regulations related to seawater discharge are strong.

The second is a Closed Loop System that removes sulfur oxides by spraying fresh water containing additives such as sodium hydroxide (NaOH) to the scrubber as shown in FIG. 3, and unlike the Open Loop System, it is applied regardless of local regulations Although this is possible, since fresh water continues to circulate in the ship, there is a problem that salts of sulfur oxides are accumulated and scale, etc. may occur.

The third is a hybrid system in which an open loop and a closed loop are complexly applied as shown in FIG. 4 , and each of the advantages can be employed, but the system is complicated and the installation cost and operating cost are high.

As a patent related to the prior art of applying such an exhaust gas scrubber to a ship, there are Patent Registration No. 1,387,560 and Patent Publication No. 2014-0117949, etc. In the conventional exhaust gas scrubber device, exhaust gas in the process of purifying exhaust gas There is a problem in that the heat transferred from the gas to seawater or fresh water cannot be reused and is discarded through cooling water.

Therefore, there is a need for a technology capable of saving energy by efficiently utilizing waste heat of exhaust gas in such an exhaust gas scrubber system. In the present invention, in order to operate a steam turbine connected to a generator using waste heat, primarily exhaust It is intended to provide a technology that can achieve this by using the heat of the gas directly and secondarily by using the heat transferred from the exhaust gas to the fresh water of the scrubber.

Registered Patent No. 1,387,560 (2014.04.15.) Patent Publication No. 2014-0117949 (2014.10.08.)

In order to solve the above problems of the prior art, in an energy saving device in a ship and an energy recovery method using the same, the fresh water in the exhaust gas scrubber transfers the waste heat to the condensate in the waste heat recovery device, so that the waste heat is efficiently utilized An object of the present invention is to provide an energy saving device and an energy recovery method.

In addition, by additionally configuring a heat exchanger, a temperature sensor, a seawater valve, a frequency converter, etc. to stabilize the fresh water circulation system in the exhaust gas scrubber, it is intended to provide an energy saving device and an energy saving method that are efficiently operated.

The present invention provides an energy saving device in a ship including an exhaust gas scrubber and a waste heat recovery device, and more specifically, a sulfur oxide scrubber (SO _x scrubber) (11), fresh water The tank 12, the first heat exchanger 14, the first pipe (a) connecting the sulfur oxide scrubber 11 and the fresh water tank 12, and the fresh water tank 12 and the first heat exchanger 14 are connected An exhaust gas scrubber (A) including a second pipe (b), a third pipe (c) connecting the first heat exchanger (14) and the sulfur oxide scrubber (11), a marine engine (31), and a heat exchanger (34), a steam turbine (36), a condenser (37), a fourth pipe (d) connecting the marine engine (31) and the heat exchanger (34), the heat exchanger (34) and a sulfur oxide scrubber ( 11) connecting pipe (j), a fifth pipe (f) connecting the steam turbine 36 and the condenser 37, and the first heat exchanger 14 and the heat exchanger 34 in the condenser 37 Provided is an energy saving device using waste heat, including a waste heat recovery device (B) including a sixth pipe (g) that is sequentially passed through and connected to the steam turbine 36 again.

Such an energy saving device also includes a seawater pump 16, a second heat exchanger 15 installed on the third pipe c, and a first discharge pipe h connected from the seawater pump 16 to the outside of the ship 22 ) may be further included, wherein the first discharge pipe (h) may be designed to pass through the second heat exchanger (15).

In addition, a temperature sensor (1) installed on the third pipe (c) at the rear end of the second heat exchanger (15), and a seawater valve (2) installed on the first discharge pipe (h) at the front end of the second heat exchanger (15). By further including a second discharge pipe (i) connected from the seawater control unit 3, the seawater valve 2 to the outside of the ship 22, the temperature measured by the temperature sensor 1 is less than the set temperature range or the set temperature range If it exceeds, the seawater control unit 3 may be designed to control the seawater valve 2 to increase or decrease the amount of seawater discharged to the outside of the ship through the second discharge pipe i, respectively.

As another embodiment of the present invention, it may further include a temperature sensor 1 and a frequency converter 8 installed on the third pipe c at the rear end of the second heat exchanger 15, which When the temperature measured by the temperature sensor 1 is less than the set temperature range or exceeds the set temperature range, the frequency converter 8 controls the seawater pump 16 to determine the amount of seawater supplied by the seawater pump 16, respectively. It is designed to decrease or increase.

or an auxiliary temperature sensor 7 installed on the first discharge pipe h at the rear end of the second heat exchanger 15 instead of the temperature sensor 1, so that the temperature measured by the auxiliary temperature sensor 7 is set temperature If it exceeds, the frequency converter 8 controls the seawater pump 16, it may be designed to reduce the amount that the seawater pump 16 supplies seawater.

The waste heat recovery device (B) of the present invention as described above is an exhaust pipe (k) connected from the heat exchanger (34) to the outside of the ship (47), a bypass valve (4) installed on the exhaust pipe (k), connection It may further include an isolation valve (5), an exhaust control unit (6) installed on the pipe (j), wherein the bypass valve (4) and/or the isolation valve (5) through the exhaust control unit (6) opening and closing can be controlled.

According to another embodiment, the present invention provides a method for recovering energy in a ship including an exhaust gas scrubber system and a waste heat recovery system.

Specifically, the step of supplying exhaust gas and fresh water to a sulfur oxide scrubber (SO _x scrubber) 11, sulfur oxide (SO _x ) contained in the exhaust gas is dissolved in the fresh water to produce sulfuric acid, the sulfuric acid is The step of storing the included fresh water in the fresh water tank 12, the step of supplying the fresh water stored in the fresh water tank 12 to the first heat exchanger 14, the fresh water passing through the first heat exchanger 14 is a sulfur oxide scrubber Exhaust gas scrubber system (A) including the step of supplying to (11), the exhaust gas discharged from the marine engine 31 is heat-exchanged with condensed water in the heat exchanger 34, passing through the heat exchanger (34) The exhaust gas is supplied to the sulfur oxide scrubber 11, the condensed water turned into steam by the heat exchanger 34 is supplied to the steam turbine 36, the steam turbine 36 The steam passing through is supplied to the condenser 37; the steam condensed by the condenser 37 is supplied to the first heat exchanger 14 to exchange heat with the fresh water, the first heat exchanger 14 Provided is an energy recovery method using waste heat including a waste heat recovery system (B) comprising the step of supplying the passed condensate to the heat exchanger (34).

In addition, in the exhaust gas scrubber system (A), the fresh water passing through the first heat exchanger 14 passes through the second heat exchanger 15 before being supplied to the sulfur oxide scrubber 11, sea water ) is supplied from the seawater pump 16 to the second heat exchanger 15 to exchange heat with the fresh water, and the seawater passing through the second heat exchanger 15 may further include the step of discharging to the outside 22 of the ship. can

On the other hand, the exhaust gas scrubber system (A) of the present invention is a step in which the temperature of the fresh water that has passed through the second heat exchanger 15 is measured, when the measured temperature is less than the set temperature range or exceeds the set temperature range, the seawater pump It may further include a control step of increasing or decreasing the amount of seawater directly discharged from (16) to the outside of the vessel, respectively.

Alternatively, the step of measuring the temperature of the fresh water that has passed through the second heat exchanger 15, when the measured temperature is less than the set temperature range or exceeds the set temperature range, the amount of seawater supplied by the seawater pump 16 is reduced, respectively or may further include an increasing control step.

In addition, the step of measuring the temperature of the seawater that has passed through the second heat exchanger 15, when the measured temperature exceeds the set temperature, the seawater pump 16 to further include a control step of reducing the amount of seawater supplied can be configured.

In the waste heat recovery system (B) according to an embodiment of the present invention, the opening and closing of an isolation valve (5) and a bypass valve (4) are controlled, and the exhaust discharged to the outside of the ship (47) The method may further include adjusting the amount of exhaust gas supplied to the gas and the sulfur oxide scrubber 11 .

At this time, the separation valve 5 is installed on the connection pipe j for supplying exhaust gas from the heat exchanger 34 to the sulfur oxide scrubber 11 , and the bypass valve 4 is connected from the heat exchanger 34 . It may be installed on the exhaust pipe (k) for discharging the exhaust gas to the outside (47) of the ship.

In an energy saving device in a ship and an energy recovery method using the same according to an embodiment of the present invention, fresh water in an exhaust gas scrubber through a first heat exchanger transfers waste heat to condensed water in a waste heat recovery device, so that fresh water uses a separate cooling water It is cooled without heating, and the condensed water is preheated through waste heat of fresh water, so there is an effect of saving energy.

In addition, since the second heat exchanger is additionally configured, the fresh water circulation system in the exhaust gas scrubber can be stabilized, and a temperature sensor, a sea water valve, a frequency converter, etc. are further included so that the temperature of the fresh water and the temperature of the sea water used to cool the fresh water can be efficiently controlled.

1 is a graph showing the emission of _{sulfur oxides (SO x} ) regulated according to MARPOL ANNEX IV.
Figure 2 schematically shows an Open Loop System in a conventional exhaust gas scrubber system.
3 is a schematic view of a Closed Loop System in a conventional exhaust gas scrubber system.
Figure 4 schematically shows a Hybrid Loop System in a conventional exhaust gas scrubber system.
Figure 5 schematically shows an energy saving device using waste heat in a ship including an exhaust gas scrubber (A) and a waste heat recovery device (B) according to an embodiment of the present invention will be.
6 schematically shows a configuration further including an auxiliary temperature sensor 7 and a frequency converter 8 in an energy saving device using waste heat in a ship according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, but should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

Terms such as “first” and “second” are for distinguishing one component from another, and the scope of rights should not be limited by these terms. For example, a first component may be termed a second component, and similarly, a second component may also be termed a first component.

In each step, the identification code is used for convenience of description, and the identification code does not describe the order of each step, and each step may be performed differently from the specified order unless the specific order is clearly stated in the context. have. That is, each step may be performed in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

Throughout this specification, the term “front end” of a specific member refers to any direction in which any fluid enters and enters the specific member, and likewise, the term “rear end” of a specific member refers to the direction in which any fluid flows out of the specific member. means all directions.

Figure 5 schematically shows an energy saving device using waste heat in a ship including an exhaust gas scrubber (A) and a waste heat recovery device (B) according to an embodiment of the present invention will be.

As shown in FIG. 5, the energy saving device using waste heat in a ship of the present invention is composed of an exhaust gas scrubber (A) and a waste heat recovery device (B).

First, the exhaust gas scrubber (A) is a sulfur oxide scrubber (SO _x scrubber) (11), the fresh water tank (12), the first heat exchanger (14), the sulfur oxide scrubber (11) and the fresh water tank (12) to connect The first pipe (a), the second pipe (b) connecting the fresh water tank 12 and the first heat exchanger 14, and the third pipe connecting the first heat exchanger 14 and the sulfur oxide scrubber 11 (c) is included.

The sulfur oxide scrubber 11 is a device for purifying the exhaust gas by removing _{sulfur oxides (SO x ) contained in the exhaust gas.} Fresh water is sprayed. At this time, the sulfur oxide contained in the exhaust gas is melted and removed in the fresh water to purify the exhaust gas, and the purified exhaust gas is discharged to the outside 24 of the ship.

An exhaust gas monitoring device 20 may be additionally installed on the pipe through which the exhaust gas is discharged to the outside of the ship 24 , and the concentration of pollutants such as sulfur oxides contained in the exhaust gas through the exhaust gas monitoring device 20 is measured. By being measured, the degree of pollution of the exhaust gas discharged to the outside of the ship 24 can be confirmed.

On the other hand, sulfur oxides dissolved in fresh water react with fresh water to produce sulfuric acid, and fresh water containing such sulfuric acid can be purified through neutralization reaction, dilution, and injection of additives. In the present specification, sulfuric acid is a term that includes both _{sulfuric acid (H 2} SO ₄ ) and sulfurous acid (H ₂ SO _{3 ).}

In particular, the fresh water may be neutralized by reacting with sodium hydroxide supplied from the sodium hydroxide (NaOH) tank 13 , and Na ₂ SO ₄ is produced as a by-product. In this case, it is preferable to use an aqueous sodium hydroxide solution containing 50% by weight of sodium hydroxide as the sodium hydroxide.

This neutralization reaction may proceed in the sulfur oxide scrubber 11, may proceed in the fresh water tank 12 to which sodium hydroxide is supplied, or may proceed throughout the system circulating the exhaust gas scrubber A.

The fresh water used to purify the exhaust gas is supplied to and stored in the fresh water tank 12 through the first pipe (a), and the sodium hydroxide tank 13 as described above may be connected to the fresh water tank 12 .

On the other hand, as the number of times that fresh water circulates through the exhaust gas scrubber A and the exhaust gas is washed is accumulated, there is a problem that _{pollutants other than sulfur oxides or Na 2} SO _{4 as a by-product of the neutralization reaction are accumulated in the fresh water.}

Accordingly, a water treatment pipe (l) connecting the water treatment device 17, the fresh water tank 12 and the water treatment device 17 is further installed, so that a part of the fresh water stored in the fresh water tank 12 is transferred to the water treatment pipe (l) This problem can be solved by being discharged to the water treatment device 17 through the water treatment device 17 and being filled with fresh fresh water.

However, since it is undesirable in terms of energy saving or limited space utilization in the vessel to always wash contaminated fresh water from the ship or replace it with fresh water, there is a certain level of contaminants in the fresh water circulating the exhaust gas scrubber (A). It is necessary to have a system that allows the above process to occur only when it is accumulated.

In order to implement such a system, the exhaust gas scrubber (A) of the present invention includes a Na ₂ SO ₄ sensor (9) installed in a fresh water tank (12), a water treatment valve (10) installed on the water treatment pipe (l), and a water treatment control unit ( 51) may be further included.

Na ₂ SO ₄ sensor 9 is the sensor for measuring the Na ₂ SO ₄ concentration of the fresh water stored in the fresh water tank 12, the higher the concentration of Na ₂ SO ₄ measured on Na ₂ SO ₄ sensor 9 above It means that the same exhaust gas washing has been done a lot, and pollutants have accumulated.

Therefore, when _{the concentration of Na 2} SO ₄ measured by the _{Na 2} SO ₄ sensor 9 exceeds the set concentration, the water treatment control unit 51 controls the water treatment valve 10 , and the water treatment device 17 from the fresh water tank 12 ) by increasing the amount of fresh water supplied to the above control system can be implemented.

The set concentration of Na ₂ SO ₄ is preferably set to a value within the range of 5 to 25 wt% of the total fresh water in the fresh water tank 12. When the set concentration of Na ₂ SO ₄ is less than 5 wt%, the water treatment device 17 ) caused a problem that the excessively widening the amount of fresh water to be discharged to, and, when the set concentrations of Na ₂ SO ₄ exceeds 25 wt% adversely affect to increase a degree of acidity or the contamination of fresh water purifying the exhaust gas or various facilities scale can occur.

The contaminated fresh water supplied to the water treatment device 17 is discharged to the outside of the ship 23 through various water treatment processes. Water quality may be measured, and sludge separated from fresh water in the water treatment process may be stored in a sludge tank 19 connected to the water treatment device 17 .

Since the exhaust gas scrubber (A) is a system that operates only when ships operate in areas such as sulfur oxide ECA, where regulations on sulfur oxide emissions are severe, the exhaust gas scrubber (A) is placed dormant in areas other than sulfur oxide ECA. It can be operated in such a way that only the facilities related to water treatment are operated, or it can be operated in a way that continuously manages impurities depending on the situation.

The fresh water stored in the fresh water tank 12 is supplied to the first heat exchanger 14 through the second pipe (b). At this time, a fresh water circulation pump 21 that provides power to smoothly circulate the fresh water through the exhaust gas scrubber A may be installed on the second pipe (b).

The first heat exchanger 14 is a device for exchanging fresh water with condensed water of a waste heat recovery device (B) to be described later. That is, by transferring the heat received from the exhaust gas to the condensed water in the process of purifying the exhaust gas, the fresh water can be cooled without using a separate cooling water, and the condensed water is supplied to the heat exchanger 34 to be described later. It can be preheated, resulting in overall energy savings.

The fresh water cooled by heat exchange in the first heat exchanger 14 is supplied to the sulfur oxide scrubber 11 again through the third pipe (c) to circulate the exhaust gas scrubber (A), and fresh water on the third pipe (c) A second heat exchanger 15 to be additionally cooled may be installed.

At this time, in addition to the second heat exchanger 15, the sea water pump 16 and a first discharge pipe (h) connected from the sea water pump 16 to the outside 22 of the ship may be further installed, the first discharge pipe (h) It is installed to pass through the second heat exchanger (15). Accordingly, the seawater supplied from the seawater pump 16 may be exchanged with fresh water by passing the second heat exchanger through the first discharge pipe h.

Such a configuration is a configuration for stabilizing the exhaust gas scrubber (A) system by additionally cooling the fresh water in the second heat exchanger 15 when the fresh water that has transferred the waste heat in the first heat exchanger 14 is not sufficiently cooled.

Additionally, the temperature sensor 1 installed on the third pipe c at the rear end of the second heat exchanger 15, the seawater valve 2 installed on the first discharge pipe h at the front end of the second heat exchanger 15, A second discharge pipe (i) connected from the seawater control unit 3 and the seawater valve 2 to the outside of the ship 22 may be further installed, and the temperature measured by the temperature sensor 1 is less than the set temperature range or the set temperature When the range is exceeded, the seawater control unit 3 controls the seawater valve 2 , thereby increasing or decreasing the amount of seawater directly discharged to the outside of the ship through the second discharge pipe i, respectively.

That is, through this configuration, the seawater directly discharged to the outside of the ship 22 through the second discharge pipe (i) according to the temperature of the fresh water that is heat-exchanged in the second heat exchanger (15) and discharged through the third pipe (c). By adjusting the amount, it is possible to adjust the supply amount of seawater used to cool the fresh water in the second heat exchanger 15 .

It is desirable to set the set temperature range of fresh water to a value of 40 ~ 60 ℃. When the temperature of fresh water is less than 40 ℃, the amount of seawater used to cool the fresh water increases excessively, and the temperature of the seawater discharged to the outside of the ship does not satisfy the regulations, and when the temperature of fresh water exceeds 60 ℃, it causes problems such as overloading various facilities in the exhaust gas scrubber (A).

Next, the waste heat recovery device (B) connects the ship engine 31 , the heat exchanger 34 , the steam turbine 36 , the condenser 37 , the ship engine 31 and the heat exchanger 34 . a fourth pipe (d), a connecting pipe (j) connecting the heat exchanger (34) and the sulfur oxide scrubber (11), a fifth pipe (f) connecting the steam turbine (36) and the condenser (37), the condenser It is composed of a sixth pipe (g) that passes through the first heat exchanger 14 and the heat exchanger 34 in sequence at (37) and is connected to the steam turbine 36 again.

The marine engine 31 generates power by burning fuel, and in this process, exhaust gas containing various pollutants such as _{sulfur oxides (SO x} ) and nitrogen oxides (NO _{x ) is generated.}

Exhaust gas is supplied to the heat exchanger 34 through the fourth pipe (d) to exchange heat with condensate, before passing through a power turbine 32 or a turbocharger 33, It can transmit kinetic energy.

The exhaust gas is heat-exchanged by transferring waste heat to condensate in the heat exchanger 34 , and then is supplied to the sulfur oxide scrubber 11 of the exhaust gas scrubber A through the connection pipe j to be purified.

At this time, the exhaust pipe (k) connected from the heat exchanger (34) to the outside of the ship (47), a bypass valve (4) located on the exhaust pipe (k), a separation valve located on the connection pipe (j) An isolation valve 5 and an exhaust control unit 6 may be further installed, and the opening and closing of the bypass valve 4 and/or the isolation valve 5 may be controlled through the exhaust control unit 6 .

This is to prevent unnecessary operation of the exhaust gas scrubber (A) by further closing the separation valve (5) and further opening the bypass valve (4) when operating in an area where sulfur oxide regulation is not severe, and sulfur oxide ECA (Emission Control Area) ) is configured to increase the amount of exhaust gas discharged through the exhaust gas scrubber (A) by further opening the separation valve (5) and closing the bypass valve (4) only when operating in heavily regulated areas such as ).

In addition to being composed of separate valves such as the bypass valve (4) and the separation valve (5) as above, a pipe directly discharged to the outside of the ship (47) and a pipe connected to the exhaust gas scrubber (A) are connected to one valve By configuring so that the exhaust gas flow rate may be adjusted.

Meanwhile, the condensed water receives waste heat of exhaust gas from the heat exchanger 34 and is converted into steam, and the steam is used as a power source of a steam turbine 36 connected to a generator, a water supply/hot water system, and the like.

The steam used for driving the steam turbine 36 is supplied to the condenser 37 through the fifth pipe (f) and is changed into condensed water. The condensed water undergoes a circulation process in which the condensed water is supplied back to the steam turbine 36 through a sixth pipe (g), in which the sixth pipe (g) connects the first heat exchanger 14 and the heat exchanger 34 described above By being installed to pass sequentially, the condensate may be preheated in the first heat exchanger 14 and then converted into steam in the heat exchanger 34 and delivered to the steam turbine 36 .

That is, the main purpose of the operation of the first heat exchanger 14 is to transfer heat to the condensate of the waste heat recovery device (B), and the operation of the second heat exchanger 15 is the operation of the exhaust gas scrubber (A) as described above. Stabilization is the main goal.

On this sixth pipe (g), a condensate circulation pump 38 for smoothly circulating condensed water, a condensate tank 39 for storing condensed water, and a feed water pump 40 for supplying condensed water to the first heat exchanger 14 or multi-stage A heat exchange device 41 may be installed.

The multi-stage heat exchange device 41 is a device for preheating condensate and cooling scavenge air of the engine. In the first stage 41a, heat is transferred from the scavenge air to the condensed water, and in the second stage 41b, the cooling water is transferred from the scavenge air. heat is transferred to

On the other hand, the heat exchanger 34 may be configured as a multi-stage heat exchanger, and after condensed water passes through the heat exchanger 34 firstly and exchanges heat with exhaust gas to become two phases of water and steam, a vapor separator Heat exchange may be performed in such a way that the steam supplied to the (steam separator) 35 and separated from the water passes through the heat exchanger 34 again to become superheated steam.

6 schematically shows a configuration further including an auxiliary temperature sensor 7 and a frequency converter 8 in an energy saving device using waste heat in a ship according to an embodiment of the present invention.

As shown in FIG. 6, the present invention provides an auxiliary temperature sensor 7 installed on the third pipe c at the rear end of the second heat exchanger 15 instead of the seawater valve 2 and the second discharge pipe i, and It can be designed to further include a frequency converter 8 .

The frequency converter 8 is a generic name for a device that converts AC power of a certain frequency into AC power of another frequency, and is based on the temperature of fresh water and/or seawater measured by the temperature sensor 1 and/or the auxiliary temperature sensor 7 It is a device for controlling the seawater pump 16 to change the amount of seawater supplied.

That is, if the temperature of the fresh water measured by the temperature sensor 1 is lower than the set temperature range, it means that heat exchange has been excessively performed. This means that it is insufficiently done, so it can be controlled in a way that increases the seawater supply.

It is desirable to set the set temperature range of fresh water to a value of 40 ~ 60 ℃. When the temperature of fresh water is less than 40 ℃, the amount of seawater used to cool the fresh water increases excessively, and the temperature of the seawater discharged to the outside of the ship does not satisfy the regulations, and when the temperature of fresh water exceeds 60 ℃, it causes problems such as overloading various facilities in the exhaust gas scrubber (A).

In addition, since the temperature regulation must be satisfied when the seawater used to cool the fresh water is discharged to the outside 22 of the ship, if the temperature of the seawater measured by the auxiliary temperature sensor 7 is higher than the set temperature, the seawater of the seawater pump 16 It can also be controlled in a way that reduces the supply. The set temperature of seawater preferably has a value within the range of 45 to 55 ℃, but is not limited thereto, and may vary according to seawater discharge temperature regulation.

In addition to this method, if the difference between the temperature measured by the temperature sensor 1 and the auxiliary temperature sensor 7 exceeds the set range, the frequency converter 8 controls the seawater pump 16, so that the seawater pump 16 is It may be controlled to increase the amount of seawater supplied.

This means that when the temperature difference between the fresh water and seawater heat-exchanged with each other is excessive, the heat exchange is not sufficiently performed, so the seawater pump 16 is controlled to increase the seawater supply amount.

As such, when the frequency converter 8 is applied instead of the seawater valve 2 as shown in FIG. 5 , the seawater is discharged directly to the outside of the ship 22 through a bypass line such as the second discharge pipe i. Since there is no such thing, there is an advantage in that the energy required to operate the seawater pump 16 can be reduced as much as possible.

The ship of the present invention to which such an energy saving device and energy recovery method are applied is a ship, an onshore plant, an offshore plant, a Floating Production Storage Offloading (FPSO), and other offshore structures and facilities. It is the broadest concept that includes all of them.

The present invention is not limited to the specific embodiments and descriptions described above, and various modifications can be made by anyone skilled in the art without departing from the gist of the present invention as claimed in the claims. and such modifications shall fall within the protection scope of the present invention.

1: Temperature sensor 2: Seawater valve
3: Seawater control 4: Bypass valve
5: Separation valve 6: Exhaust control
7: auxiliary temperature sensor 8: frequency converter
9: Na ₂ SO ₄ sensor 10: water treatment valve
11: Sulfur oxide scrubber 12: Fresh water tank
13: sodium hydroxide tank 14: first heat exchanger
15: second heat exchanger 16: sea water pump
17: water treatment device 18: fresh water monitoring device
19: sludge tank 20: exhaust gas monitoring device
21: fresh water circulation pump 22, 23, 24, 47: outside the ship
31: marine engine 32: power turbine
33: turbocharger 34: heat exchanger
35: steam separator 36: steam turbine
37: condenser 38: condensate circulation pump
39: condensate tank 40: water pump
41: multi-stage heat exchange device 41a: first stage
41b: tier 2 43: scavenging air source
44: scavenging source 45: cooling water source
46: coolant discharge source a: first pipe
b: second pipe c: third pipe
d: fourth pipe f: fifth pipe
g: sixth pipe h: first discharge pipe
i: second discharge pipe j: connector
k: exhaust pipe l: water treatment pipe

Claims (12)

In an energy saving device in a ship including an exhaust gas scrubber and a waste heat recovery device,
The exhaust gas scrubber (A),
sulfur oxide scrubber (SO _x scrubber) (11); fresh water tank (12); a first heat exchanger (14);
a first pipe (a) connecting the sulfur oxide scrubber 11 and the fresh water tank 12; a second pipe (b) connecting the fresh water tank 12 and the first heat exchanger 14; and a third pipe (c) connecting the first heat exchanger 14 and the sulfur oxide scrubber 11;
Waste heat recovery device (B),
marine engine 31; heat exchanger (34); steam turbine 36; condenser 37;
a fourth pipe (d) connecting the marine engine 31 and the heat exchanger 34; a connection pipe (j) connecting the heat exchanger (34) and the sulfur oxide scrubber (11); a fifth pipe (f) connecting the steam turbine 36 and the condenser 37; and a sixth pipe (g) connected to the steam turbine 36 again by sequentially passing through the first heat exchanger 14 and the heat exchanger 34 in the condenser 37; . The method of claim 1,
The exhaust gas scrubber (A),
seawater pump (16);
a second heat exchanger 15 installed on the third pipe (c); and
A first discharge pipe (h) connected from the seawater pump 16 to the outside of the ship 22;
Energy saving device using waste heat, characterized in that the first discharge pipe (h) passes through the second heat exchanger (15). 3. The method of claim 2,
The exhaust gas scrubber (A),
a temperature sensor (1) installed on the third pipe (c) at the rear end of the second heat exchanger (15);
Seawater valve (2) installed on the first discharge pipe (h) of the front end of the second heat exchanger (15);
seawater control unit (3); and
A second discharge pipe (i) connected from the seawater valve (2) to the ship exterior (22); further comprising
When the temperature measured by the temperature sensor 1 is less than the set temperature range or exceeds the set temperature range, the seawater control unit 3 controls the seawater valve 2 and is discharged to the outside of the vessel through the second discharge pipe (i). An energy saving device using waste heat, characterized in that increasing or decreasing the amount of seawater, respectively. 3. The method of claim 2,
The exhaust gas scrubber (A),
a temperature sensor (1) installed on the third pipe (c) at the rear end of the second heat exchanger (15); and
It further comprises a frequency converter (8);
When the temperature measured by the temperature sensor 1 is less than the set temperature range or exceeds the set temperature range, the frequency converter 8 controls the seawater pump 16 to determine the amount of seawater supplied by the seawater pump 16, respectively. An energy saving device using waste heat, characterized in that it decreases or increases. 3. The method of claim 2,
The exhaust gas scrubber (A),
Auxiliary temperature sensor (7) installed on the first discharge pipe (h) at the rear end of the second heat exchanger (15); and
It further comprises a frequency converter (8);
When the temperature measured by the auxiliary temperature sensor (7) exceeds the set temperature, the frequency converter (8) controls the seawater pump (16), characterized in that the seawater pump (16) reduces the amount of seawater supplied. , an energy saving device using waste heat. The method of claim 1,
Waste heat recovery device (B),
an exhaust pipe (k) connected from the heat exchanger (34) to the outside of the vessel (47);
a bypass valve (4) installed on the exhaust pipe (k);
an isolation valve (5) installed on the connecting pipe (j); and
Further comprising an exhaust control (6),
An energy saving device using waste heat, characterized in that opening and closing of the bypass valve (4) and/or the separation valve (5) is controlled through the exhaust control unit (6). In an energy recovery method in a ship comprising an exhaust gas scrubber system and a waste heat recovery system,
Exhaust gas scrubber system (A),
Exhaust gas and fresh water is supplied to the sulfur oxide scrubber (SO _x scrubber) (11);
_{Sulfuric acid (SO x} ) contained in the exhaust gas is dissolved in the fresh water to generate sulfuric acid;
storing the fresh water containing the sulfuric acid in the fresh water tank 12;
supplying the fresh water stored in the fresh water tank 12 to the first heat exchanger 14; and
Including; supplying the fresh water that has passed through the first heat exchanger (14) to the sulfur oxide scrubber (11);
Waste heat recovery system (B),
Exchanging the exhaust gas discharged from the marine engine 31 with condensed water in the heat exchanger 34;
The exhaust gas passing through the heat exchanger 34 is supplied to the sulfur oxide scrubber 11;
supplying a steam turbine (36) with condensed water turned into steam by means of a heat exchanger (34);
supplying steam passing through a steam turbine 36 to a condenser 37;
a step of supplying the steam which has become condensed water by the condenser 37 to the first heat exchanger 14 to exchange heat with the fresh water; and
and supplying the condensed water that has passed through the first heat exchanger (14) to the heat exchanger (34). 8. The method of claim 7,
Exhaust gas scrubber system (A),
The fresh water passing through the first heat exchanger 14 passes through the second heat exchanger 15 before being supplied to the sulfur oxide scrubber 11;
a step of supplying sea water from the sea water pump 16 to the second heat exchanger 15 to exchange heat with the fresh water; and
Discharging the seawater that has passed through the second heat exchanger (15) to the outside of the ship (22). 9. The method of claim 8,
Exhaust gas scrubber system (A),
measuring the temperature of the fresh water that has passed through the second heat exchanger 15; and
When the measured temperature is less than the set temperature range or exceeds the set temperature range, a control step of increasing or decreasing the amount of seawater directly discharged from the seawater pump 16 to the outside of the ship, respectively; energy recovery method using 9. The method of claim 8,
Exhaust gas scrubber system (A),
measuring the temperature of the fresh water that has passed through the second heat exchanger 15; and
When the measured temperature is less than the set temperature range or exceeds the set temperature range, a control step in which the amount of seawater supplied by the seawater pump 16 is decreased or increased, respectively; Energy recovery using waste heat, characterized in that it further comprises; Way. 9. The method of claim 8,
Exhaust gas scrubber system (A),
Measuring the temperature of the seawater that has passed through the second heat exchanger (15); and
When the measured temperature exceeds the set temperature, the control step of reducing the amount of seawater supplied by the seawater pump 16; Energy recovery method using waste heat, characterized in that it further comprises. 8. The method of claim 7,
Waste heat recovery system (B),
The opening and closing of the isolation valve 5 and the bypass valve 4 are controlled so that the amount of exhaust gas discharged to the outside of the ship 47 and the exhaust gas supplied to the sulfur oxide scrubber 11 is reduced. Further comprising the step of adjusting,
The separation valve 5 is installed on the connection pipe j that supplies exhaust gas from the heat exchanger 34 to the sulfur oxide scrubber 11, and the bypass valve 4 is connected from the heat exchanger 34 to the outside of the vessel 47 ), characterized in that it is installed on the exhaust pipe (k) for discharging the exhaust gas, an energy recovery method using waste heat.

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