JP2012037089A - Heat recovery unit, exhaust gas economizer and waste heat recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent sulfuric acid corrosion and to increase a heat recovery amount when recovering heat of the exhaust gas of an engine even when two or more kinds of fuels of different sulfur contents are selectively used.SOLUTION: A branch pipe 21 is branched from an exit pipe 15 of an exhaust gas economizer 10, and a secondary heat recovery part 22 for recovering the heat of the exhaust gas is provided on the branch pipe 21. A switching means 23 is put in a first state of discharging the exhaust gas which has flown into the exit pipe 15 from the exit pipe 15 without making it pass through the branch pipe 21 when the engine 1 is using a high sulfur fuel such as residue oil, and is put in a second state of making the exhaust gas which has flown into the exit pipe 15 pass through the branch pipe 21 and discharging it when the engine 1 is using a low sulfur fuel such as distillate oil and gas oil.

Description

  The present invention relates to an exhaust gas economizer and a waste heat recovery system that recovers heat of exhaust gas of an engine.

  A ship equipped with a diesel engine may be equipped with a waste heat recovery system to save energy. As such a waste heat recovery system, a system in which the heat of the exhaust gas of the engine is recovered by an exhaust gas economizer, steam is generated by the recovered heat, and the steam turbine is driven by the generated steam is known. (For example, see Patent Documents 1 to 3).

  If the fuel used in the engine contains a sulfur content, the sulfur content becomes sulfuric acid gas by combustion and is discharged from the engine. When the surface temperature of the heating pipe of the exhaust gas economizer falls below the dew point of sulfuric acid, the sulfuric acid gas condenses into sulfuric acid, and depending on the amount of condensation, sulfuric acid corrosion occurs in the heating pipe of the exhaust gas economizer. For this reason, when providing a waste heat recovery system equipped with an exhaust gas economizer, it is required to design the exhaust gas economizer so that the outlet temperature of the exhaust gas economizer is kept sufficiently high to prevent sulfuric acid corrosion.

JP-A-1-208602 JP-A-5-65804 JP-A-7-217815

  By the way, as a fuel for marine diesel engines, residual oil (C heavy oil) which is relatively inexpensive but has a relatively high sulfur content is often used in order to reduce transportation costs. In contrast, in recent years, marine diesel engines have been strongly requested to reduce sulfur oxides in exhaust gas from the viewpoint of protecting the air environment. Sea area). Therefore, in order to reduce sulfur oxides in the exhaust gas, it is required to convert the fuel to be used into distillate oil (A heavy oil) or light oil, which is a low sulfur fuel having a lower sulfur content than the residual oil. ing.

  However, low sulfur fuel is more expensive than residual oil, and the amount of fuel required for navigation is enormous. Therefore, as a practical operational form of a ship, low-sulfur fuel is used when navigating in the designated sea area, and residual oil is used when navigating in other sea areas. One type of fuel can be selectively used, thereby preventing the increase in transportation costs while clearing regulations in designated sea areas.

  Here, assuming the use of residual oil, in order to prevent sulfuric acid corrosion, it is necessary to keep the outlet temperature of the exhaust gas economizer sufficiently higher than the sulfuric acid dew point temperature, and it is necessary to keep it at about 160 ° C. or more, which is effective and safe. It is a sufficient condition. On the other hand, when low sulfur fuel is assumed to be used, sulfuric acid corrosion does not occur even if heat recovery is performed until the outlet temperature of the exhaust gas economizer becomes lower.

  Then, if the exhaust gas economizer is designed in accordance with the use of low-sulfur fuel, the outlet temperature of the exhaust gas economizer becomes lower than about 160 ° C., so that it is impossible to prevent sulfuric acid corrosion when using residual oil. . Conversely, if the exhaust gas economizer is designed to match the use of the residual oil, the exhaust gas economizer outlet temperature will be about 160 ° C or higher, so when using low-sulfur fuel, the heat that should have been recovered is wasted. It will be.

  Therefore, the present invention prevents sulfuric acid corrosion and reduces the amount of heat recovered when recovering the heat of engine exhaust gas, even in the case where one of a plurality of types of fuels having different sulfur contents is selectively used. The purpose is to balance the increase.

  The present invention has been made to achieve the above object, and the heat recovery unit of the exhaust gas economizer according to the present invention is a heat recovery unit provided in the exhaust gas economizer having a primary heat recovery unit that recovers the heat of the exhaust gas of the engine. A branch pipe branched from an outlet pipe of the exhaust gas economizer, a secondary heat recovery section for recovering heat of the exhaust gas guided by the branch pipe, and the branch pipe for exhaust gas flowing into the outlet pipe of the exhaust gas economizer Switching means for switching between a first state in which discharge is made from the outlet pipe without passing through a pipe and a second state in which discharge is made through passage of the branch pipe, and the switching means is configured so that the engine is high. When the sulfur fuel is used, the engine is in the first state, and the engine uses a low sulfur fuel having a lower sulfur content than the high sulfur fuel. It is configured to be the second state to.

  According to this configuration, when the high sulfur fuel such as residual oil is used, the exhaust gas after the heat recovery by the primary heat recovery section is discharged as it is from the outlet pipe without being led to the branch pipe by the operation of the switching device. On the other hand, when using low-sulfur fuel, the exhaust gas after heat recovery by the primary heat recovery section is guided from the outlet pipe to the branch pipe, further recovered by the secondary heat recovery section, and then discharged from the branch pipe. That is, excess heat of the exhaust gas is recovered by the secondary heat recovery unit only when low sulfur fuels such as distillate oil and light oil are used. For this reason, when the high sulfur fuel is used, the outlet temperature of the outlet pipe can be kept at a relatively high temperature, whereby sulfuric acid corrosion can be satisfactorily prevented. When using low-sulfur fuel, heat recovery by the secondary heat recovery unit can satisfactorily prevent heat from being exhausted and increase the amount of heat recovered from the exhaust gas.

  The switching means includes: a first damper that opens and closes a downstream side of the outlet pipe from a connection portion with the branch pipe; and a second damper that opens and closes the upstream side of the branch pipe from the secondary heat recovery unit. In the first state, the first damper increases the opening of the outlet pipe and the second damper decreases the opening of the branch pipe, and in the second state, the first damper The damper may reduce the opening of the outlet pipe and the second damper may increase the opening of the branch pipe. Thereby, the switching device which exhibits the above-mentioned operation is suitably realized. Note that “increasing the opening” includes not only full opening but also an intermediate opening near the full opening, and “decreasing the opening” does not only open the entire opening but also the intermediate opening near the full closing. Including the degree.

  An exhaust gas economizer according to the present invention includes an inlet pipe that guides exhaust gas of an engine, a primary heat recovery part that recovers heat of the exhaust gas guided by the inlet pipe, and exhaust gas after heat recovery by the primary heat recovery part flows in An outlet pipe and the heat recovery unit described above are provided.

  In addition, a waste heat recovery system according to the present invention includes the above-described exhaust gas economizer and a steam turbine driven by steam generated using heat of exhaust gas recovered by the exhaust gas economizer as a heat source.

  In these configurations as well, as in the heat recovery unit described above, both sulfuric acid corrosion is well prevented and heat is well discharged, and the amount of exhaust gas heat recovered is increased. Can be made. In addition, the steam turbine can be driven using the recovered heat.

  The apparatus further comprises a first steam separator and a second steam separator for supplying steam to the steam turbine, wherein the primary heat recovery section of the exhaust gas economizer includes a first heat recovery section and the first heat recovery section. A second heat recovery part located downstream of the first part, wherein the first heat recovery part constitutes a part of the circulating water system of the first steam separator, and the first air recovery part Forming a first evaporator for generating steam from the circulating water of the water separator, wherein the second heat recovery unit constitutes a part of the circulating water system of the second steam separator, A second evaporator that generates steam from the circulating water of the steam separator, and the secondary heat recovery unit constitutes a part of the circulating water system of the second steam separator, You may comprise the preheater which heats the said circulating water before supply to a said 2nd heat recovery part.

  The first steam separator is a high-pressure steam separator, the first evaporator is a high-pressure evaporator that generates high-pressure steam, and the second steam-water separator is a low-pressure steam-water separator. In addition, the second evaporator may be a low-pressure evaporator that generates low-pressure steam having a pressure lower than that of the high-pressure steam.

  An air cooler that cools the scavenging air to the engine, and the air cooler is provided in a water supply system for supplying water to the high-pressure steam separator and the low-pressure steam separator. You may comprise the feed water heater which heats water by replacement | exchange.

  An air cooler that cools scavenging air to the engine, and the circulating water system of the low-pressure steam-water separator is connected to the low-pressure steam-water separator via the secondary heat recovery section and the second heat recovery section. A line returning to the steam separator, and a line returning from the low pressure steam separator to the low pressure steam separator via the air cooler, wherein the air cooler is the low pressure evaporation formed by the second heat recovery unit. A second low-pressure evaporator that generates low-pressure steam having a pressure lower than that of the high-pressure steam from the circulating water of the low-pressure steam-water separator may be formed independently of the steam generator.

  The first steam separator is a high-pressure steam separator, the first evaporator is a high-pressure evaporator that generates high-pressure steam, and the second steam-water separator is a medium-pressure steam-water separator. And the second evaporator is an intermediate pressure evaporator that generates intermediate pressure steam having a pressure lower than that of the high pressure steam, and cools the scavenging gas to the engine, and a low pressure steam / water separator that supplies the steam to the steam turbine. An air cooler that forms part of the circulating water system of the low-pressure steam separator, and generates low-pressure steam that is lower in pressure than the medium-pressure steam from the circulating water of the low-pressure steam separator. A low-pressure evaporator may be formed.

  The apparatus further comprises a high-pressure steam separator for supplying steam to the steam turbine, an intermediate-pressure steam separator, and a low-pressure steam separator, wherein the primary heat recovery section of the exhaust gas economizer is a first heat recovery section and the first heat recovery section. A second heat recovery part located downstream of the heat recovery part, wherein the first heat recovery part constitutes a part of a circulating water system of the high pressure steam separator, and the high pressure steam separator A high-pressure evaporator that generates high-pressure steam from the circulating water of the steam generator, and the second heat recovery unit constitutes a part of the circulating water system of the intermediate-pressure steam-water separator, and the circulation of the medium-pressure steam-water separator An intermediate pressure evaporator that generates intermediate pressure steam at a pressure lower than that of the high pressure steam from water is formed, and the secondary heat recovery unit constitutes a part of a circulating water system of the low pressure steam separator, and the low pressure A low-pressure evaporator that generates low-pressure steam having a pressure lower than that of the intermediate-pressure steam from the circulating water of the steam separator may be formed.

  An air cooler for cooling scavenging air to the engine, the air cooler being provided in a water supply system for supplying water to the high pressure steam separator, the medium pressure steam separator, and the low pressure steam separator, You may comprise the feed water heater which heats water by heat exchange with the waste heat of an engine.

  An air cooler that cools scavenging air to the engine, and a circulating water system of the low-pressure steam-water separator returns from the low-pressure steam-water separator to the low-pressure steam-water separator via the secondary heat recovery unit And a line that returns from the low-pressure steam-water separator to the low-pressure steam-water separator via the air cooler, and the air cooler is independent of the low-pressure evaporator formed by the secondary heat recovery unit, You may comprise the 2nd low pressure evaporator which produces | generates low pressure steam lower pressure than the said intermediate pressure steam from the circulating water of the said low pressure steam-water separator.

  An air cooler for cooling the scavenging air to the engine, wherein the low-pressure steam separator includes a first low-pressure steam separator and a second low-pressure steam separator, and the secondary heat recovery section is Forming a part of the circulating water system of the first low-pressure steam separator, forming a first low-pressure evaporator that generates low-pressure steam from the circulating water of the first low-pressure steam separator, An air cooler forms a part of the circulating water system of the first low-pressure steam separator, and forms a second low-pressure evaporator that generates low-pressure steam from the circulating water of the second low-pressure steam separator. It may be.

  A generator connected to the output shaft of the steam turbine, a power turbine that is rotationally driven by exhaust gas of the engine, and a clutch that connects and disconnects power transmission between the output shaft of the power turbine and the generator. Furthermore, you may provide.

  Thus, according to the present invention, the heat of the exhaust gas of the engine can be obtained even in the case where one kind of a plurality of kinds of fuels having different sulfur contents such as residual oil, distillate oil and light oil is selectively used. In the recovery, it is possible to achieve both prevention of sulfuric acid corrosion and increase in the amount of heat recovery.

1 is a system diagram of a waste heat recovery system according to a first embodiment of the present invention. It is a systematic diagram of the waste heat recovery system which concerns on 2nd Embodiment of this invention. It is a systematic diagram of the waste heat recovery system which concerns on 3rd Embodiment of this invention. It is a systematic diagram of the waste heat recovery system which concerns on 4th Embodiment of this invention. It is a systematic diagram of the waste heat recovery system which concerns on 5th Embodiment of this invention. It is a systematic diagram of the waste heat recovery system which concerns on 6th Embodiment of this invention. It is a systematic diagram of the waste heat recovery system which concerns on 7th Embodiment of this invention. It is a systematic diagram of the waste heat recovery system which concerns on 8th Embodiment of this invention. It is a conceptual diagram which shows the structure of the exhaust gas economizer and heat recovery unit which concern on embodiment of this invention.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the following description of these embodiments, the same or corresponding elements as those of the above-described embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

[First Embodiment]
FIG. 1 is a system diagram of a waste heat recovery system 101 according to the first embodiment of the present invention. As shown in FIG. 1, a waste heat recovery system 101 includes an exhaust gas economizer 10 and a heat recovery unit 20 that recover the heat of exhaust gas from a marine diesel engine 1 (hereinafter referred to as engine 1) mounted on a ship. Steam is generated by the heat recovered by the economizer 10 and the heat recovery unit 20, and the turbo generator 2 is driven by the steam. The turbo generator 2 is formed by connecting an AC generator 2b to an output shaft of a multistage steam turbine 2a that is rotationally driven by steam. The engine 1 can selectively use one of a plurality of types of fuels having different sulfur contents, and as a fuel option, residual oil which is a high sulfur fuel having a relatively high sulfur content, or sulfur rather than residual oil. There are distillate oil and light oil, which are low-sulfur fuels with little content.

(Exhaust gas economizer and heat recovery unit)
FIG. 9 is a conceptual diagram showing configurations of the exhaust gas economizer 10 and the heat recovery unit 20 according to the embodiment of the present invention. As shown in FIG. 9, the exhaust gas economizer 10 is connected to the engine 1 via the exhaust pipe 3. A bypass pipe 4 that bypasses the exhaust gas economizer 10 is connected to the exhaust pipe 3, and the inlets of the bypass pipe 4 and the exhaust gas economizer 10 are opened and closed by dampers 5 and 6. In the following description, it is assumed that the bypass pipe 4 is closed and the inlet of the exhaust gas economizer 10 is open.

  The exhaust gas economizer 10 includes an inlet pipe 11, a first heat recovery part 12, an intermediate pipe 13, a second heat recovery part 14 and an outlet pipe 15 in this order from the upstream side. The inlet pipe 11 is connected to the exhaust pipe 3 and guides the exhaust gas from the engine 1 to the first heat recovery unit 12. The intermediate pipe 13 guides the exhaust gas after the heat exchange by the first heat recovery unit 12 to the second heat recovery unit 14. Exhaust gas after heat exchange by the second heat recovery unit 14 flows into the outlet pipe 15.

  The 1st heat recovery part 12 and the 2nd heat recovery part 14 are each provided with heat exchange pipes 12A and 14A which constitute a part of circulation water system which makes circulating water flow of an air-water drum (air-water separator). Yes. The circulating water flowing through the heat exchange pipes 12A and 14A changes from liquid to vapor by heat exchange with the exhaust gas (that is, by recovering the heat of the exhaust gas). The circulating water is returned to the steam drum in a steam-water mixture. Conversely, the exhaust gas is cooled by heat exchange with the circulating water in the first heat recovery unit 12 and the second heat recovery unit 14.

  Further, a heat exchange pipe 11 </ b> A is provided on the downstream side of the damper 6 in the inlet pipe 11. The heat exchange pipe 11A is connected in parallel to a steam system that supplies the high-pressure steam from the high-pressure drum 41 to the turbo generator 2, and functions as a super heater that further heats the high-pressure steam by heat exchange with the exhaust gas. When the high-pressure steam flows through the heat exchange pipe 11 </ b> A, the exhaust gas also falls in the process of passing through the inlet pipe 11.

  A heat recovery unit 20 is added to the outlet of the exhaust gas economizer 10. The heat recovery unit 20 includes a branch pipe 21, a secondary heat recovery unit 22, and switching means 23. The branch pipe 21 is connected to the outlet pipe 15 and extends so as to branch from the outlet pipe 15. That is, the outlet portion of the exhaust gas economizer 10 has a structure that is bifurcated from the middle of the outlet pipe 15 to the downstream portion of the outlet pipe 15 and the branch pipe 21. It can be discharged from the outlet of the pipe 15 or can be discharged from the outlet of the branch pipe 21.

  The secondary heat recovery unit 22 is provided on the branch pipe 21. The branch pipe 21 passes through the exhaust gas after heat recovery by the first heat recovery unit 12 and the second heat recovery unit 14, but the secondary heat recovery unit 22 further transfers the heat of the exhaust gas to the secondary pipe 21. To recover. In other words, the heat exchange pipe 11A in the inlet pipe 11, the heat exchange pipe 12A of the first heat recovery section 12, and the heat exchange pipe 14A of the second heat recovery section 14 are exhaust gas economizers 10 that primarily recover the heat of the exhaust gas. Functions as the primary heat recovery unit 16.

  The secondary heat recovery unit 22 includes a heat exchange pipe 22A that constitutes a part of the circulating water system through which the circulating water of the air-water drum flows. The circulating water flowing through the heat exchange pipe 22A is heated by exchanging heat with the exhaust gas (that is, by recovering the heat of the exhaust gas) or becomes liquid to vapor. The circulating water heat exchanged with the exhaust gas in the secondary heat recovery unit 22 is sent to the primary heat recovery unit 16 or the air-water drum. Conversely, the exhaust gas that passes through the branch pipe 21 is further cooled by heat exchange with the circulating water.

  The switching means 23 is in a first state in which the exhaust gas flowing into the outlet pipe 15 is discharged from the outlet pipe 15 as it is without passing through the branch pipe 21 and in a second state in which the exhaust gas is discharged through the branch pipe 21. Switch. The switching means 23 of the present embodiment includes a first damper 24 that opens and closes a downstream side of a connection portion with the branch pipe 21 in the outlet pipe 15, and an upstream side of the secondary heat recovery unit 22 in the branch pipe 21. And a second damper 25 that opens and closes. The 1st damper 24 and the 2nd damper 25 consist of butterfly valves, for example, and the operation of the 1st damper 24 and the 2nd damper 25 is electronically controlled by the controller 26.

  The controller 26 controls the switching means 23 to be in the first state when high-sulfur fuel such as residual oil is used as the fuel for the engine 1. That is, the first damper 24 and the second damper 25 are controlled so that the opening degree of the outlet pipe 15 is increased and the opening degree of the branch pipe 21 is reduced. At this time, the opening degree of the outlet pipe 15 and the opening degree of the branch pipe 21 are sufficient to prevent the exhaust gas from being guided to the branch pipe 21 due to the difference in flow resistance between the outlet pipe 15 and the branch pipe 21. In an extreme situation, the outlet pipe 15 is fully opened and the branch pipe 21 is fully closed.

  Thereby, after the heat of the exhaust gas from the engine 1 is recovered by the primary heat recovery unit 16, the exhaust gas is discharged from the outlet of the outlet pipe 15 to the outside of the ship. Therefore, the amount of heat recovered in the primary heat recovery unit 16 is ensured to a temperature at which the outlet temperature of the outlet pipe 15 is sufficiently high (for example, 160 ° C.) to prevent sulfuric acid corrosion even when high sulfur fuel is used. It is set to be.

  On the other hand, when a low-sulfur fuel such as distillate oil or light oil is used as the fuel for the engine 1, the switching means 23 is controlled to be in the second state. That is, the first damper 24 and the second damper 25 are controlled so that the opening degree of the outlet pipe 15 is reduced and the opening degree of the branch pipe 21 is increased. The opening degree of the outlet pipe 15 and the branch pipe 21 at this time is also sufficiently large so that the exhaust gas flows through the branch pipe 21 in the same manner as described above. In an extreme situation, the outlet pipe 15 is fully closed and the branch pipe 21 is fully opened.

  Thereby, the heat of the exhaust gas from the engine 1 is recovered not only by the primary heat recovery unit 16 but also by the secondary heat recovery unit 22, and after the recovery, the exhaust gas is discharged out of the ship from the outlet of the branch pipe 21. Become.

  Then, the outlet temperature of the branch pipe 21 is lower than the outlet temperature of the outlet pipe 15 by the amount of heat recovered by the secondary heat recovery unit 22, but the outlet is lower when using low sulfur fuel than when using high sulfur fuel. Even if the temperature is lowered, sulfuric acid corrosion does not occur. Therefore, the amount of heat recovered by the secondary heat recovery unit 22 is such that the outlet temperature of the branch pipe 21 is sufficiently high (for example, 120 to 140 ° C.) to prevent sulfuric acid corrosion even when low sulfur fuel is used. ) Is set so as to be secured.

  Thereby, sulfuric acid corrosion can be satisfactorily prevented both when using high sulfur fuel and when using low sulfur fuel. In addition, when using low-sulfur fuel, the outlet temperature that should be secured to prevent sulfuric acid corrosion at that time and the outlet temperature that should be secured to prevent sulfuric acid corrosion when using high-sulfur fuel. The amount of heat corresponding to the difference (for example, 20 to 40 ° C.) is recovered. Therefore, not only when using high-sulfur fuel but also when using low-sulfur fuel, the amount of heat that can be recovered on the premise of prevention of sulfuric acid corrosion is recovered, and the exhaust gas economizer 10 and waste heat are recovered. The efficiency of the collection system 1 is improved.

  In addition, although the case where the switching means 23 is provided with the two dampers 24 and 25 was illustrated, the switching means 23 is not restricted to this and can be changed suitably. For example, when the flow resistance of the downstream portion of the outlet pipe 15 is sufficiently smaller than the flow resistance of the branch pipe 21, a damper including a butterfly valve or the like may be provided only in the downstream portion of the outlet pipe 15. The primary heat recovery unit 16 may include one, two, or four or more heat recovery units, and the secondary heat recovery unit 22 may include two or more heat recovery units. A method for determining whether the fuel used is a high sulfur fuel or a low sulfur fuel is not particularly limited. For example, when fuel tanks are individually loaded according to the type of fuel, it is possible to detect which tank fuel is supplied to the engine 1 and control the switching means 23 based on the detection result. Good. Further, the sulfur content in the fuel supplied to the engine 1 may be analyzed, and the switching means 23 may be controlled based on the analysis result. The heat recovered by the exhaust gas economizer 10 and the heat recovery unit 20 may be used for purposes other than the generation of steam.

(Waste heat recovery system)
Hereinafter, returning to FIG. 1, the configuration of the waste heat recovery system 101 according to the first embodiment will be specifically described. The waste heat recovery system 101 includes an exhaust gas economizer 10 and a heat recovery unit 20, a high pressure drum (auxiliary boiler or high pressure steam / water separator) 41, a low pressure drum (low pressure steam / water separator) 42, a condenser 51, and a water supply system. 61, a high-pressure circulating water system 62, a steam system 63, a low-pressure circulating water system 64, and a low-pressure mixed system 65 are provided.

  A condenser 51 for condensing the steam that has passed through the turbine 2a is provided at the steam outlet of the steam turbine 2a. A water supply system 61 for supplying condensed water to the drums 41 and 42 is connected to the condenser 51. When the feed water pump 61P is driven, the water condensed in the condenser 51 is supplied to the air cooler 53 that cools the scavenging gas to the engine 1 through the feed water filter tank 52 and flows through the air cooler 53. It is heated by heat exchange with the waste heat of the engine 1. The water heated by the air cooler 53 is supplied to the drums 41 and 42 via the water supply system 61.

  A high-pressure circulating water system 62 is connected to the high-pressure drum 41, and water supplied through the water supply system 61 circulates as circulating water in the high-pressure circulating water system 62. The high-pressure circulating water system 62 includes a line 62A that connects the high-pressure drum 41 to one end of the heat exchange pipe 12A (see FIG. 9) of the first heat recovery unit 12, the heat exchange pipe 12A, and the other end of the heat exchange pipe 12A. And a line 62B connected to the high-pressure drum 41. When the circulation pump 62P on the line 62A is driven, the circulating water is supplied from the high-pressure drum 41 to the heat exchange pipe 12A via the line 62A, and heat exchange with the exhaust gas is performed in the process of flowing through the heat exchange pipe 12A. It becomes high-pressure steam. The circulating water that has become high-pressure steam returns to the high-pressure drum 41 through the line 62B.

  A steam system 63 is connected to the high-pressure drum 41, and the high-pressure steam sent to the high-pressure drum 41 is separated from liquid water in the high-pressure drum 41, and the steam turbine of the turbo generator 2 is connected via the steam system 63. 2a. The heat exchange pipe 11A described above is connected in parallel to the steam system 63, and the high-pressure steam sent out from the high-pressure drum 41 is further heated by heat exchange with the exhaust gas while flowing through the heat exchange pipe 11A.

  Further, a low-pressure circulating water system 64 is connected to the low-pressure drum 42, and water supplied to the low-pressure drum 42 via the water supply system 61 circulates as circulating water in the low-pressure circulating water system 64. The low-pressure circulating water system 64 includes a line 64A connecting the low-pressure drum 42 to one end of the heat exchange pipe 22A (see FIG. 9) of the secondary heat recovery unit, the heat exchange pipe 22A, and the other end of the heat exchange pipe 22A. 2 has a line 64C connected to one end of the heat exchange pipe 14A (see FIG. 9) of the heat recovery section 14, a heat exchange pipe 14A, and a line 64B connecting the other end of the heat exchange pipe 14A to the low-pressure drum 42. When the circulation pump 64P on the line 64A is driven, the circulating water in the low-pressure drum 42 flows in order through the line 64A, the heat exchange pipe 22A, the line 64C, the heat exchange pipe 14A, and the line 64B and returns to the low-pressure drum 42. .

  Since exhaust gas does not pass through the branch pipe 21 when the high sulfur fuel is used, the circulating water is supplied to the heat exchange pipe 14A without exchanging heat in the heat exchange pipe 22A and flows through the heat exchange pipe 14A. Heat exchange with the exhaust gas results in low-pressure steam, and the circulating water that has become low-pressure steam returns to the low-pressure drum 42. On the other hand, when the low sulfur fuel is used, since the exhaust gas passes through the branch pipe 21, the circulating water is heated by heat exchange with the exhaust gas in the process of flowing through the heat exchange pipe 22A. The heated circulating water becomes low-pressure steam by heat exchange with the exhaust gas in the process of flowing through the heat exchange pipe 14 </ b> A, and the circulating water that has become low-pressure steam returns to the low-pressure drum 42.

  A low-pressure mixture system 65 is connected to the low-pressure drum 42, and the low-pressure steam sent to the low-pressure drum 42 is separated from liquid water in the low-pressure drum 42, and the turbo generator is connected via the low-pressure mixture system 65. 2 is supplied to the second steam turbine 2a.

  Thus, in this embodiment, the 1st heat recovery part 12 is provided with heat exchange pipe 12A which constitutes a part of high-pressure circulating water system 62, and makes steam from circulating water of high-pressure drum 41 heat from exhaust gas as a heat source. It functions as the high-pressure evaporator 31 to be generated. The second heat recovery unit 14 includes a heat exchange pipe 14A that constitutes a part of the low-pressure circulating water system 64, and functions as a low-pressure evaporator 32 that generates steam from the circulating water of the low-pressure drum 42 using the heat of exhaust gas as a heat source. . The turbo generator 2 is configured to be driven by the supply of steam generated by the high-pressure evaporator 31 and the low-pressure evaporator 32, and can increase the power that can be generated.

  In the present embodiment, the secondary heat recovery unit 22 of the heat recovery unit 20 includes a heat exchange pipe 22A that constitutes a part of the low-pressure circulating water system 64, and circulates the low-pressure drum 42 using the heat of the exhaust gas as a heat source. It functions as a preheater 33 that heats water before supplying it to the low-pressure evaporator 32. In this way, heat that can be recovered is used on the premise of preventing sulfuric acid corrosion and the circulating water is heated, so that the recoverable heat amount of the waste heat recovery system 101 can be increased, and turbo power generation The power that can be generated by the machine 2 can be increased.

  Moreover, in this embodiment, the air cooler 53 of the engine 1 functions as the feed water heater 61Q that heats the feed water. Thus, since the waste heat of the engine 1 is also recovered, the recoverable heat amount of the waste heat recovery system 101 can be further increased, and the power that can be generated by the turbo generator 2 can be increased.

  The high pressure drum 41 and the low pressure drum 42 have heaters 41A and 42A, respectively. The steam system 63 may be provided with a steam outlet (see US mark in the drawing) for extracting high-pressure steam, and the heaters 41A and 42A may be driven by the high-pressure steam extracted from the steam outlet. Thereby, the circulating water in the drums 41 and 42 can be heated by the heaters 41A and 42A before being sent to the circulating water systems 62 and 64.

[Second Embodiment]
FIG. 2 is a system diagram of the waste heat recovery system 102 according to the second embodiment. The high-pressure drum 41, the high-pressure circulating water system 62, and the steam system 63 according to this embodiment are the same as in the first embodiment, and the first heat recovery unit 12 functions as the same high-pressure evaporator 31 as described above. The low-pressure drum 42 and the low-pressure mixed system 65 are the same as in the first embodiment. This embodiment is different from the first embodiment in that the water supply system 61 and the low-pressure circulating water system 64 are changed.

  As shown in FIG. 2, the water supply system 61 is separated from the air cooler 53. The water supply system 61 includes a line 61A for connecting the condenser 51 to the high pressure drum 41, and a line 61B branched from the line 61A and connected to the low pressure drum 42, and includes a water supply filter tank 52 and a water supply pump 61P. Is provided on the line 61A and upstream of the branch point with the line 61B. In addition, on the line 61A, on the downstream side of the branch point with the line 61B, an exhaust eco water heater 54 for cooling the cooling water of the engine 1 is provided. The water flowing through the line 61A becomes a refrigerant when viewed from the cooling water of the engine 1, and is heated by heat exchange with the cooling water.

  The low pressure drum 42 is supplied with water from the condenser 51 without being heated. The low-pressure circulating water system 64 has the same lines 64A, 64B, 64C and heat exchange pipes 14A, 22A as in the first embodiment. That is, also in the present embodiment, the second heat recovery unit 14 and the secondary heat recovery unit 22 function as the low-pressure evaporator 32 and the preheater 33 similar to the above.

  The low-pressure circulating water system 64 further includes a line 64D branched from the line 64A and connected to the inlet of the air cooler 53, and a line 64E connecting the outlet of the air cooler 53 to the low-pressure drum 42. When the circulation pump 64Q on the line 64D is driven, the circulating water is supplied from the low-pressure drum 42 to the air cooler 53 via the line 64D, and exchanges heat with the waste heat of the engine 1 in the process of flowing through the air cooler 53. As a result, low pressure steam is obtained. The circulating water that has become low-pressure steam is returned to the low-pressure drum 42 via the line 64E.

  Thus, in this embodiment, the waste eco water heater 54 functions as a water heater 61Q instead of the air cooler 53, and the air cooler 53 constitutes a part of the low-pressure circulating water system 64, and the engine 1 It functions as a second low-pressure evaporator 34 that generates steam from the circulating water of the low-pressure drum 42 by using the waste heat as a heat source. As described above, the waste heat recovery system 102 according to the present embodiment also recovers the heat of scavenging of the engine 1, so that the recoverable heat amount can be increased compared to the first embodiment, and the turbo The power that can be generated by the generator 2 can be increased.

[Third Embodiment]
FIG. 3 is a system diagram of the waste heat recovery system 103 according to the third embodiment of the present invention. The high-pressure drum 41, the high-pressure circulating water system 62, and the steam system 63 according to this embodiment are the same as those of the first and second embodiments, and the first heat recovery unit 12 functions as the same high-pressure evaporator 31 as described above. The low-pressure drum 42 and the low-pressure mixed system 65 are the same as those in the first and second embodiments. In this embodiment, an intermediate pressure drum 43 (intermediate pressure air / water separator), an intermediate pressure circulating water system 66 and an intermediate pressure mixed system 67 are added, and a low pressure circulating water system 64 is changed. This is different from the first and second embodiments.

  As shown in FIG. 3, the water supply system 61 is provided with an air cooler 53 as in the first embodiment. In the present embodiment, the air cooler 53 functions as the water supply heater 61Q. The water heated by the air cooler 53 is also supplied to the intermediate pressure drum 43 along with the high pressure drum 41 and the low pressure drum 42 via the water supply system 61.

  The low-pressure circulating water system 64 includes a line 64A connecting the low-pressure drum 42 to one end of the heat exchange pipe 22A (see FIG. 9) of the secondary heat recovery unit 22, the heat exchange pipe 22A, and the other end of the heat exchange pipe 22A. And a line 64 </ b> F connected to the low-pressure drum 42. When the circulation pump 64P on the line 64A is driven, the circulating water in the low-pressure drum 42 passes through the line 64A, the heat exchange pipe 22A, and the line 64F in order and returns to the low-pressure drum 42.

  When the high sulfur fuel is used, the exhaust gas does not pass through the branch pipe 21, so that the circulating water returns to the low pressure drum 42 without exchanging heat in the heat exchange pipe 22A. On the other hand, when the low sulfur fuel is used, since the exhaust gas passes through the branch pipe 21, the circulating water becomes low-pressure steam by heat exchange with the heat of the exhaust gas in the process of flowing through the heat exchange pipe 22A, and becomes low-pressure steam. Circulating water returns to the low pressure drum 42. Therefore, the low pressure drum 42 supplies steam to the steam turbine 2a via the low pressure mixed system 65 only when the low sulfur fuel is used.

  An intermediate pressure circulating water system 66 is connected to the intermediate pressure drum 43, and water supplied into the intermediate pressure drum 42 through the water supply system 61 circulates as circulating water in the intermediate pressure circulating water system 66. The intermediate pressure circulating water system 66 includes a line 66A that connects the intermediate pressure drum 43 to one end of the heat exchange pipe 14A (see FIG. 9) of the second heat recovery unit 14, a heat exchange pipe 14A, and the heat exchange pipe 14A. A line 66B connecting the end to the intermediate pressure drum 43. When the circulation pump 66P on the line 66A is driven, the circulating water is supplied from the intermediate pressure drum 43 to the heat exchange pipe 14A through the line 66A, and is exchanged with the exhaust gas in the process of passing through the heat exchange pipe 14A. It becomes medium pressure steam. The circulating water that has become the medium pressure steam returns to the medium pressure drum 43 via the line 66B.

  An intermediate pressure mixture system 67 is connected to the intermediate pressure drum 43, and the intermediate pressure steam sent to the intermediate pressure drum 41 is separated from liquid water in the intermediate pressure drum 43, and the intermediate pressure mixture system 67. Is supplied to the steam turbine 2a of the turbo generator 2.

  As described above, in the present embodiment, the second heat recovery unit 14 includes the heat exchange pipe 14A that constitutes a part of the intermediate pressure circulating water system 66, and uses the heat of the exhaust gas as the heat source from the circulating water of the intermediate pressure drum 43. It functions as an intermediate pressure evaporator 35 that generates steam. The secondary heat recovery unit of the heat recovery unit 20 includes a heat exchange pipe 22A that forms part of the low-pressure circulating water system 64, and generates low-pressure steam from the circulating water of the low-pressure drum 42 using the heat of the exhaust gas as a heat source. The low-pressure evaporator 36 functions as the evaporator 36 and is independent of the medium-pressure evaporator 35. The turbo generator 2 is configured to be driven by the supply of steam generated by the high-pressure evaporator 31, the intermediate-pressure evaporator 35, and the low-pressure evaporator 36, thereby increasing the power that can be generated. it can.

  The intermediate-pressure drum 43 may be provided with a heater 43A similar to the high-pressure drum 41 and the low-pressure drum 42. Thereby, the circulating water in the intermediate pressure drum 43 can be heated by the heater 43 </ b> A before being sent to the intermediate pressure circulating water system 66.

[Fourth Embodiment]
FIG. 4 is a system diagram of the waste heat recovery system 104 according to the fourth embodiment of the present invention. The high-pressure drum 41, the high-pressure circulating water system 62, and the steam system 63 according to the present embodiment are the same as those in the first to third embodiments, and the first heat recovery unit 12 functions as the same high-pressure evaporator 31 as described above. The low-pressure drum 42, the intermediate-pressure drum 43, the low-pressure mixed system 65, and the intermediate-pressure mixed system 67 according to the present embodiment are the same as those in the third embodiment. The present embodiment is different from the first to third embodiments in that the water supply system 61, the low-pressure circulating water system 64, and the intermediate-pressure circulating water system 66 are changed.

  As shown in FIG. 4, the water supply system 61 is separated from the air cooler 53 in the same manner as the second embodiment, and a waste eco water heater 54 is provided on a line 61 </ b> A that connects the condenser 51 to the high-pressure drum 41. The waste eco water heater 54 functions as the water heater 61Q. The heated water is supplied not only to the high pressure drum 41 but also to the intermediate pressure drum 43 via the line 61A.

  The low-pressure circulating water system 64 has a line 64D that connects the low-pressure drum 42 to the inlet of the air cooler 53, and a line 64E that connects the outlet of the air cooler 53 to the low-pressure drum 42. When the circulation pump 64Q on the line 64D is driven, the circulating water is supplied from the low-pressure drum 42 to the air cooler 53 via the line 64D, and exchanges heat with the waste heat of the engine 1 in the process of flowing through the air cooler 53. As a result, low pressure steam is obtained. The circulating water that has become low-pressure steam is returned to the low-pressure drum 42 via the line 64E.

  The intermediate pressure circulating water system 66 includes a line 66C that connects the intermediate pressure drum 43 to one end of the heat exchange pipe 22A (see FIG. 9) of the secondary heat recovery unit 22, a heat exchange pipe 22A, and the heat exchange pipe 22A. A line 66D connecting one end of the heat exchange pipe 14A (see FIG. 9) of the second heat recovery unit 14 to the one end of the heat exchange pipe 14A, and a line 66B connecting the other end of the heat exchange pipe 14A and the heat exchange pipe 14A to the intermediate pressure drum 43. And have. When the circulation pump 66P on the line 66C is driven, the circulating water in the intermediate pressure drum 43 flows in order through the line 66C, the heat exchange pipe 22A, the line 66D, the heat exchange pipe 14A, and the line 66B, and the intermediate pressure drum 43 is reached. Return to.

  Since exhaust gas does not pass through the branch pipe 21 when using high sulfur fuel, the circulating water is supplied to the heat exchange pipe 14A without exchanging heat in the heat exchange pipe 22A, and exhaust gas is exhausted in the process of flowing through the heat exchange pipe 14A. The medium pressure steam is obtained by heat exchange with the circulating water, and the circulating water that has become the medium pressure steam returns to the medium pressure drum 43. On the other hand, when the low sulfur fuel is used, since the exhaust gas passes through the branch pipe 21, the circulating water is heated by heat exchange with the exhaust gas in the process of flowing through the heat exchange pipe 22A. The heated circulating water becomes intermediate pressure steam by heat exchange with the exhaust gas in the process of flowing through the heat exchange pipe 14 </ b> A, and the circulating water that has become intermediate pressure steam returns to the low pressure drum 42.

  As described above, in the present embodiment, the low-pressure circulating water system 64 is not connected to the exhaust gas economizer 10 and the heat recovery unit 20, and the air cooler 53 alone circulates the low-pressure drum 42 using the waste heat of the engine 1 as a heat source. It functions as a low-pressure evaporator 34 that generates steam from water. Thereby, it is possible to supply the steam from the low-pressure drum 42 to the steam turbine 2a both when the high sulfur fuel is used and when the low sulfur fuel is used.

  And in this embodiment, the 2nd heat recovery part 14 is provided with the heat exchange pipe 14A which comprises a part of intermediate pressure circulating water system | strain 66, and uses the heat | fever of waste gas as a heat source, and it is steam from the circulating water of the intermediate pressure drum 43 The secondary heat recovery unit 22 of the heat recovery unit 20 includes a heat exchange pipe 22A that forms part of the intermediate pressure circulating water system 66, and uses the heat of the exhaust gas as a heat source. It functions as a preheater 33 that heats the circulating water in the intermediate pressure drum 42 before supplying it to the intermediate pressure evaporator 35.

[Fifth Embodiment]
FIG. 5 is a system diagram of the waste heat recovery system 105 according to the fifth embodiment of the present invention. The water supply system 61 according to the present embodiment is the same as that of the fourth embodiment, and the waste eco water heater 54 functions as the same water heater 61Q as described above. The high-pressure drum 41, the high-pressure circulating water system 62, and the steam system 63 according to this embodiment are the same as those in the first to fourth embodiments, and the first heat recovery unit 12 functions as the same high-pressure evaporator 31 as described above. The intermediate pressure drum 43, the intermediate pressure circulating water system 66, and the intermediate pressure mixed gas system 67 according to the present embodiment are the same as those of the third embodiment, and the second heat recovery unit 14 functions as the intermediate pressure evaporator 35 similar to the above. To do. The low-pressure drum 42 and the low-pressure mixture system 65 according to this embodiment are the same as those in the third and fourth embodiments. This embodiment is different from the first to fourth embodiments in that the low-pressure circulating water system 64 is changed.

  The low-pressure circulating water system 64 has lines 64A and 64F and a heat exchange pipe 22A (see FIG. 9), as in the third embodiment. When the high sulfur fuel is used, the circulating water returns to the low pressure drum 42 without exchanging heat with the exhaust gas. When low-sulfur fuel is used, the circulating water is converted into steam by heat exchange with the exhaust gas in the process of flowing through the heat exchange pipe 22 </ b> A, and the circulating water converted into steam returns to the low-pressure drum 42.

  Similarly to the second embodiment, the low-pressure circulating water system 64 includes a line 64D branched from the line 64A and connected to the inlet of the air cooler 53, and a line 64E connecting the outlet of the air cooler 53 to the low-pressure drum 42. Have When the circulation pump 64Q on the line 64D is driven, the circulating water is supplied from the low-pressure drum 42 to the air cooler 53 via the line 64D, and exchanges heat with the waste heat of the engine 1 in the process of flowing through the air cooler 53. It becomes steam. The circulating water that has become steam returns to the low-pressure drum 42 via the line 64E.

  Thus, in the present embodiment, the secondary heat recovery unit 22 of the heat recovery unit 20 functions as the first low-pressure evaporator 36 that generates steam from the circulating water of the low-pressure drum 42 using the heat of the exhaust gas as a heat source, The air cooler 53 functions as a second low-pressure evaporator 34 that generates steam from the circulating water of the low-pressure drum 42 using the waste heat of the engine 1 as a heat source.

[Sixth Embodiment]
FIG. 6 is a system diagram of the waste heat recovery system 106 according to the sixth embodiment of the present invention. The high-pressure drum 41, the high-pressure circulating water path 62, and the steam system 63 according to this embodiment are the same as those in the first to fifth embodiments, and the first heat recovery unit 12 functions as the high-pressure evaporator 31 similar to the above. The intermediate pressure drum 43, the intermediate pressure circulating water path 66, and the intermediate pressure mixed gas system 67 are the same as those in the third embodiment, and the second heat recovery unit 12 functions as the intermediate pressure evaporator 35. The present embodiment is provided with two low-pressure drums, ie, a first low-pressure drum 42 and a second low-pressure drum 44, and a second low-pressure circulating water system 68 and a second low-pressure mixture system 69 for the second low-pressure drum 44 are added. This is different from the first to fifth embodiments in that the water supply system 61 is changed.

  As shown in FIG. 6, the water supply system 61 is separated from the air cooler 53 in the same manner as in the fourth and fifth embodiments, and a waste eco water heater 54 is provided on a line 61A. 54 functions as a feed water heater 61Q similar to the above. The heated water is supplied to the high pressure drum 41 and the intermediate pressure drum 43. A line 61B branched from the line 61A is connected to the first low-pressure drum 42 and the second low-pressure drum 44, and the water condensed in the condenser 51 is supplied to the drums 42 and 44 by an exhaust eco-feed water heater 54. Supplied without heating.

  The first low-pressure circulating water system 64 connected to the first low-pressure drum 42 is the same as the low-pressure circulating water system according to the third embodiment. That is, the first low-pressure circulating water system 64 includes a line 64A that connects the first low-pressure drum 42 to one end of the heat exchange pipe 22A of the secondary heat recovery unit 22, the heat exchange pipe 22A, and the other end of the heat exchange pipe 22B. When the circulating pump 64P on the line 64A is driven, the circulating water in the first low-pressure drum 42 flows into the line 64A, the heat exchange pipe 22A, and the line 64A. 64F is passed in order and returns to the first low-pressure drum 42. When the high sulfur fuel is used, the circulating water returns to the first low-pressure drum 42 without exchanging heat with the exhaust gas. When the low sulfur fuel is used, the circulating water becomes steam by heat exchange with the heat of the exhaust gas in the process of flowing through the heat exchange pipe 22 </ b> A, and the circulating water that has become steam returns to the first low-pressure drum 42.

  The first low-pressure mixture system 65 connected to the first low-pressure drum 42 is the same as the low-pressure mixture system according to the first to fifth embodiments. That is, the low-pressure steam sent to the first low-pressure drum 42 when the low-sulfur fuel is used is separated from liquid water in the first low-pressure drum 42, and is connected to the turbo generator 2 via the first low-pressure mixture system 65. To the steam turbine 2a.

  A second low-pressure circulating water system 68 is connected to the second low-pressure drum 44, and water supplied via the line 61 </ b> B of the water supply system 61 circulates as circulating water in the second low-pressure circulating water system 68. The second circulating water system 68 includes a line 68A that connects the second low-pressure drum 44 to the inlet of the air cooler 53, and a line 68B that connects the outlet of the air cooler 53 to the second low-pressure drum 44. When the circulation pump 68P on the line 68A is driven, the circulating water is supplied from the second low-pressure drum 44 to the air cooler 53 via the line 68A, and the heat with the waste heat of the engine 1 is passed through the air cooler 53. The exchanged water becomes low-pressure steam, and the circulating water that has become low-pressure steam returns to the second low-pressure drum 44 via the line 68B.

  The second low-pressure drum 44 is connected to a second low-pressure mixture system 69, and the vapor sent to the second low-pressure drum 44 is separated from the liquid water in the second low-pressure drum 44, so that the second low-pressure mixture 44 It is sent to the air system 69. Since the second low-pressure mixed system 69 is connected to the first low-pressure mixed system 67, the low-pressure steam sent out from the second low-pressure drum 44 goes to the steam turbine 2 a together with the steam sent out from the first low-pressure drum 42. Supplied.

  Thus, in the present embodiment, the secondary heat recovery unit 22 of the heat recovery unit 20 functions as the first low-pressure evaporator 36 that generates steam from the circulating water of the first low-pressure drum 42 using the heat of the exhaust gas as a heat source. In addition, the air cooler 53 functions as a second low-pressure evaporator 34 that generates steam from the circulating water of the second low-pressure drum 42 using the waste heat of the engine 1 as a heat source.

  Since two low-pressure drums are provided, and only the secondary heat recovery unit 22 generates steam from the circulating water of the first low-pressure drum 42, the heat recovery unit 20 and the first low-pressure drum 42 are close to each other. Can be arranged. Then, for example, the heat recovery unit 20 and the first low-pressure drum 42 can be packaged and stored together in the chimney of the ship, so that the degree of freedom in layout of the waste heat recovery system can be increased.

  The first low-pressure drum 42 and the second low-pressure drum 44 may be provided with heaters 42A and 44A similar to the high-pressure drum 41. Thus, the circulating water in the first low-pressure drum 42 and the second low-pressure drum 44 is heated by the heaters 42A and 44A before being sent to the first low-pressure circulating water system 64 and the second low-pressure circulating water system 68, respectively. be able to.

[Seventh Embodiment]
FIG. 7 is a system diagram of the waste heat recovery system 107 according to the seventh embodiment of the present invention. This embodiment is different from the waste heat recovery system 102 according to the second embodiment in that a power turbine 71 is added.

  As shown in FIG. 7, an exhaust introduction pipe 73 is connected to the exhaust pipe 2 of the engine 1, and the power turbine 71 is rotationally driven by the exhaust gas guided by the exhaust introduction pipe 73. The output shaft of the power turbine 71 is connected to the AC generator 2b of the turbo generator 2 via the clutch 72. When the clutch 72 is in the engaged state, the turbo generator is driven by the power generated by the power turbine 71. 2 AC generator 2b is driven. An exhaust outlet pipe 74 is connected to the gas outlet of the power turbine 71, and the gas that has passed through the power turbine 71 returns to the exhaust pipe 3 through the exhaust outlet pipe 74. As described above, when the waste heat recovery system 107 includes the power turbine 71, the turbo generator 2 can be generated as compared with the waste heat recovery system 102 according to the second embodiment that does not include the power turbine 71. Power can be increased dramatically.

[Eighth Embodiment]
FIG. 8 is a system diagram of the waste heat recovery system 108 according to the eighth embodiment of the present invention. In the waste heat recovery system 108 according to the present embodiment, the power turbine 71, the clutch 72, the exhaust introduction pipe 73, and the exhaust discharge pipe 74 according to the seventh embodiment are applied to the waste heat recovery system 105 according to the fifth embodiment. It has become a thing. Even in this case, the power that can be generated by the turbo generator 2 can be dramatically increased as compared with the waste heat recovery system 105 according to the fifth embodiment that does not include the power turbine 71.

  Although the embodiment according to the present invention has been described so far, the above configuration can be appropriately changed within the scope of the present invention. For example, the power turbine 71 according to the seventh and eighth embodiments may be applied to the waste heat recovery systems 101, 103, 104, and 106 according to the first, third, fourth, and sixth embodiments.

  The present invention has the effect of being able to achieve both prevention of sulfuric acid corrosion and increase in the amount of heat recovery in recovering heat of exhaust gas from an engine that can selectively use multiple types of fuels having different sulfur contents. When it is applied to a waste heat recovery system for marine diesel engines, it is possible to achieve clearing of exhaust gas regulations and suppression of soaring transportation costs, as well as preventing sulfuric acid corrosion and increasing heat recovery. Will be very beneficial.

101-108 Waste heat recovery system 1 Marine diesel engine 2 Turbo generator 2a Steam turbine 3 Exhaust pipe 10 Exhaust gas economizer 11 Inlet pipe 11A Heat exchange pipe 12 First heat recovery section 12A Heat exchange pipe 13 Intermediate pipe 14 Second heat recovery section 14A heat exchange pipe 15 outlet pipe 16 primary heat recovery section 20 heat recovery unit 21 branch pipe 22 secondary heat recovery section 22A heat exchange pipe 23 switching means 24 first damper 25 second damper 26 controller 31 high pressure evaporator 32 low pressure evaporation 33 Preheater 34 (Second) Low pressure evaporator 35 Medium pressure evaporator 36 (First) Low pressure evaporator 41 High pressure drum 42 (First) Low pressure drum 43 Intermediate pressure drum 44 Second low pressure drum 51 Condenser 53 Air cooler 54 Waste Eco Water Heater 61 Water Supply System 61Q Water Heater 62 High Pressure Circulating Water System 63 Steam System 64 (First) Low Pressure Circulating Water System 6 (First) low admission system pressure in the circulation water system 67 in 66 圧混 exhaust system 68 second low-pressure feed water system 69 second low pressure admission line 71 power turbine

Claims (14)

A heat recovery unit provided in an exhaust gas economizer having a primary heat recovery part for recovering heat of exhaust gas of an engine,
A branch pipe branched from the outlet pipe of the exhaust gas economizer;
A secondary heat recovery section for recovering the heat of the exhaust gas guided by the branch pipe;
Switching means for switching between a first state in which the exhaust gas flowing into the outlet pipe of the exhaust gas economizer is discharged from the outlet pipe without passing through the branch pipe and a second state in which the exhaust gas is discharged through the branch pipe And comprising
The switching means is in the first state when the engine is using high sulfur fuel, and the second switching means is when the engine is using low sulfur fuel having a lower sulfur content than the high sulfur fuel. Exhaust gas economizer heat recovery unit configured to be in a state. The switching means includes: a first damper that opens and closes a downstream side of the outlet pipe from a connection portion with the branch pipe; and a second damper that opens and closes the upstream side of the branch pipe from the secondary heat recovery unit. And
In the first state, the first damper increases the opening degree of the outlet pipe and the second damper decreases the opening degree of the branch pipe. In the second state, the first damper moves the outlet pipe. The heat recovery unit of an exhaust gas economizer according to claim 1, wherein the opening degree of the pipe is decreased and the second damper increases the opening degree of the branch pipe. An inlet pipe for leading the exhaust gas of the engine,
A primary heat recovery section for recovering heat of the exhaust gas guided by the inlet pipe;
An outlet pipe into which the exhaust gas after heat recovery by the primary heat recovery section flows,
An exhaust gas economizer comprising: the heat recovery unit according to claim 1. An exhaust gas economizer according to claim 3;
A waste heat recovery system comprising: a steam turbine driven by steam generated using heat of exhaust gas recovered by the exhaust gas economizer as a heat source. A first steam separator and a second steam separator for supplying steam to the steam turbine;
The primary heat recovery part of the exhaust gas economizer has a first heat recovery part and a second heat recovery part located downstream of the first heat recovery part,
The first heat recovery unit constitutes a part of the circulating water system of the first steam separator, and forms a first evaporator that generates steam from the circulating water of the first steam separator. And
The second heat recovery unit constitutes a part of the circulating water system of the second steam separator, and forms a second evaporator that generates steam from the circulating water of the second steam separator. And
The secondary heat recovery unit constitutes a part of the circulating water system of the second steam separator, and forms a preheater that heats the circulating water before being supplied to the second heat recovery unit. The waste heat recovery system according to claim 4.   The first steam separator is a high-pressure steam separator, the first evaporator is a high-pressure evaporator that generates high-pressure steam, and the second steam-water separator is a low-pressure steam-water separator. The waste heat recovery system according to claim 5, wherein the second evaporator is a low-pressure evaporator that generates low-pressure steam having a pressure lower than that of the high-pressure steam. An air cooler that cools the scavenging air into the engine,
The air cooler is provided in a water supply system for supplying water to the high-pressure steam separator and the low-pressure steam separator, and forms a feed water heater that heats water by heat exchange with the waste heat of the engine. The waste heat recovery system according to claim 6. An air cooler that cools the scavenging air into the engine,
A circulating water system of the low pressure steam / water separator returns from the low pressure steam / water separator to the low pressure steam / water separator via the secondary heat recovery section and the second heat recovery section; A line returning from the water separator to the low-pressure steam-water separator via the air cooler,
A second low-pressure evaporator in which the air cooler generates low-pressure steam having a pressure lower than that of the high-pressure steam from circulating water of the low-pressure steam-water separator independently of the low-pressure evaporator formed by the second heat recovery unit. The waste heat recovery system of Claim 6 which comprises these. The first steam separator is a high-pressure steam separator, the first evaporator is a high-pressure evaporator that generates high-pressure steam, and the second steam-water separator is a medium-pressure steam-water separator. The second evaporator is an intermediate pressure evaporator that generates intermediate pressure steam that is lower in pressure than the high pressure steam;
A low pressure steam separator for supplying steam to the steam turbine; and an air cooler for cooling scavenging to the engine,
The air cooler constitutes a part of a circulating water system of the low-pressure steam separator, and forms a low-pressure evaporator that generates low-pressure steam having a pressure lower than that of the intermediate-pressure steam from the circulating water of the low-pressure steam-water separator. The waste heat recovery system according to claim 5. A high pressure steam separator for supplying steam to the steam turbine, a medium pressure steam separator, and a low pressure steam separator;
The primary heat recovery part of the exhaust gas economizer has a first heat recovery part and a second heat recovery part located downstream of the first heat recovery part,
The first heat recovery unit constitutes a part of a circulating water system of the high-pressure steam separator, and constitutes a high-pressure evaporator that generates high-pressure steam from the circulating water of the high-pressure steam separator;
The second heat recovery unit forms part of the circulating water system of the intermediate pressure steam separator, and generates intermediate pressure steam that is lower in pressure than the high pressure steam from the circulating water of the intermediate pressure steam separator. Form an evaporator,
The secondary heat recovery unit forms part of the circulating water system of the low-pressure steam separator, and generates low-pressure steam that is lower in pressure than the intermediate-pressure steam from the circulating water of the low-pressure steam separator. The waste heat recovery system according to claim 4 which constitutes a container. An air cooler that cools the scavenging air into the engine,
The air cooler is provided in a water supply system for supplying water to the high pressure steam / water separator, the medium pressure steam / water separator, and the low pressure steam / water separator, and heats water by heat exchange with the waste heat of the engine. The waste heat recovery system of Claim 10 which comprises the feed water heater which performs. An air cooler that cools the scavenging air into the engine,
A circulating water system of the low pressure steam / water separator returns from the low pressure steam / water separator to the low pressure steam / water separator via the secondary heat recovery unit, and the air cooler from the low pressure steam / water separator. A line through which to return to the low-pressure steam separator,
A second low-pressure evaporation in which the air cooler generates low-pressure steam having a pressure lower than that of the intermediate-pressure steam from the circulating water of the low-pressure steam-water separator independently of the low-pressure evaporator formed by the secondary heat recovery unit. The waste heat recovery system according to claim 10, which constitutes a vessel. An air cooler that cools the scavenging air into the engine,
The low-pressure steam separator includes a first low-pressure steam separator and a second low-pressure steam separator independent of each other;
The secondary heat recovery unit constitutes a part of the circulating water system of the first low-pressure steam separator, and generates a low-pressure steam from the circulating water of the first low-pressure steam separator. Form an evaporator,
The air cooler forms a part of the circulating water system of the first low-pressure steam separator, and forms a second low-pressure evaporator that generates low-pressure steam from the circulating water of the second low-pressure steam separator. The waste heat recovery system according to claim 10. A generator connected to the output shaft of the steam turbine;
A power turbine that is rotationally driven by the exhaust gas of the engine;
The waste heat recovery system according to any one of claims 4 to 13, further comprising a clutch that connects and disconnects power transmission between an output shaft of the power turbine and the generator.

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