JP2015127519A - Exhaust heat recovery device, exhaust heat recovery type vessel propulsion device and exhaust heat recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery device capable of maintaining a heat quantity to be recovered, even when a temperature of cooling water discharged from an internal combustion engine is reduced, by heating the cooling water.SOLUTION: An exhaust heat recovery type vessel propulsion device 1 comprises: a diesel engine 3; a turbocharger 4; an air cooler 5; a cooling water flow passage 7 which circulates cooling water to cool the diesel engine; and an evaporator 21 which exchanges heat between the cooling water and working fluid. The cooling water flow passage 7 has: a passage 74 which introduces the cooling water discharged from the diesel engine 3 into the evaporator 21 without involving the air cooler 5; another passage 78 which introduces the cooling water discharged from the diesel engine 3 into the evaporator 21 through the air cooler 5; and a three-way valve 8 which adjusts a first flow rate of the cooling water introduced into the evaporator 21 through the passage 74 and a second flow rate of the cooling water introduced into the evaporator 21 through the other passage 78.

Description

  The present invention relates to an exhaust heat recovery device, an exhaust heat recovery type ship propulsion device, and an exhaust heat recovery method.

2. Description of the Related Art Conventionally, an exhaust heat recovery device that recovers exhaust heat of a diesel engine of a ship and generates electric power is known (for example, see Patent Document 1).
The exhaust heat recovery device disclosed in Patent Document 1 guides the cooling water of a diesel engine to an evaporator, and guides the working fluid evaporated by the evaporator to a power turbine. And a power turbine rotates with a working fluid, and the rotational power of a power turbine is transmitted to a generator in connection with it.

  In the exhaust heat recovery apparatus disclosed in Patent Document 1, after the diesel engine cooling water is discharged from the diesel engine, it is led to an evaporator provided in the exhaust heat recovery apparatus without being heated by another heat exchanger.

JP 2012-215124 A

However, in the exhaust heat recovery apparatus disclosed in Patent Document 1, the amount of heat that can be recovered by the exhaust heat recovery apparatus depends on the temperature of the cooling water led to the evaporator.
Therefore, if the load (output) of the diesel engine which is the main engine of a ship falls, the temperature of cooling water will fall in connection with it. And with the fall of the temperature of cooling water, the calorie | heat amount which an exhaust heat recovery apparatus collect | recovers will fall, and it will become impossible to collect | recover sufficient calorie | heat amount.

  The present invention has been made to solve the above-described problem, and even when the temperature of the cooling water discharged from the internal combustion engine is lowered, the amount of heat recovered by heating the cooling water can be maintained. It is an object of the present invention to provide a possible exhaust heat recovery device, an exhaust heat recovery type ship propulsion device, and an exhaust heat recovery method.

The present invention employs the following means in order to solve the above problems.
An exhaust heat recovery apparatus according to the present invention includes an internal combustion engine, a supercharger that is driven by exhaust gas discharged from the internal combustion engine, compresses air, and supplies the compressed air to the internal combustion engine as combustion air. An air cooler for cooling the combustion air supplied from the machine to the internal combustion engine, a cooling water passage for circulating cooling water for cooling the internal combustion engine, and the cooling water and working fluid circulating through the cooling water passage A heat exchanger for exchanging heat, and the cooling water flow path includes a first flow path for guiding the cooling water discharged from the internal combustion engine to the heat exchanger without passing through the air cooler. A second flow path for guiding the cooling water discharged from the internal combustion engine through the air cooler to the heat exchanger, and is guided to the heat exchanger via the first flow path. The first flow rate of the cooling water to be discharged and the second flow path It comprises a first flow regulating valve for adjusting the second flow rate of the cooling water is led to the heat exchanger.

According to the exhaust heat recovery apparatus of the present invention, the cooling water led to the first flow path is led to the heat exchanger without being heated by the air cooler, and the cooling water led to the second flow path is air-cooled. After being heated by the vessel, it is led to the heat exchanger. The temperature of the cooling water guided to the heat exchanger rises by decreasing the first flow rate of the cooling water guided to the first flow path and increasing the second flow rate of the cooling water guided to the second flow path. Therefore, even when the temperature of the cooling water discharged from the internal combustion engine decreases, the cooling led to the heat exchanger is appropriately adjusted by adjusting the first flow rate and the second flow rate by the first flow rate adjustment valve. The water temperature is adjusted to an appropriate temperature.
Thus, it is possible to provide an exhaust heat recovery device capable of maintaining the amount of heat recovered by heating the cooling water even when the temperature of the cooling water discharged from the internal combustion engine is lowered. Can do.

The exhaust heat recovery apparatus according to the first aspect of the present invention is provided with a downstream side of the first flow rate adjustment valve, and detects the temperature of the cooling water led from the first flow rate adjustment valve to the heat exchanger. And the first flow rate adjustment valve adjusts the first flow rate and the second flow rate so that the temperature of the cooling water detected by the temperature detection unit is equal to or higher than a predetermined temperature.
By doing in this way, the 1st flow control valve adjusts so that the temperature of the cooling water led from the downstream of the 1st flow control valve to the heat exchanger of a power generation system may become more than predetermined temperature, and is collected. The amount of heat can be maintained.

In the exhaust heat recovery apparatus according to the first aspect of the present invention, the exhaust heat recovery system recovers the heat of the exhaust gas discharged from the supercharger, and the heat recovered by the exhaust heat recovery system and the heat exchange You may make it a structure provided with the auxiliary heat exchanger which performs heat exchange with the said cooling water guide | induced to a container.
By doing so, even if the temperature of the cooling water discharged from the internal combustion engine is low and the temperature of the cooling water cannot be sufficiently maintained by heating with the air cooler, the exhaust recovered by the exhaust heat recovery system The temperature of the cooling water can be maintained by the auxiliary heat exchanger using gas as a heat source.

In the above configuration, a second flow rate adjustment valve that adjusts a flow rate of the circulating water led to the auxiliary heat exchanger is provided, and the second flow rate adjustment valve has a temperature of the cooling water detected by the temperature detection unit. You may make it adjust the flow volume of the said circulating water so that it may become more than predetermined temperature.
By doing in this way, the flow volume of the circulating water guide | induced to an auxiliary heat exchanger can be adjusted appropriately so that the temperature of cooling water may become more than predetermined temperature.

In the exhaust heat recovery type ship propulsion apparatus according to the present invention, the internal combustion engine is a main engine that generates a propulsion force of the ship, and includes the exhaust heat recovery apparatus described above.
By doing in this way, even if the temperature of the cooling water discharged | emitted from an internal combustion engine falls, the waste-heat recovery-type ship propulsion apparatus which can maintain the calorie | heat amount recovered by heating a cooling water is provided. Can be provided.

  The exhaust heat recovery method according to the present invention includes a step of discharging exhaust gas, a step of compressing air with the exhaust gas to generate combustion air, a step of cooling the combustion air with cooling water, A step of exchanging heat between the cooling water and the working fluid, and a step of adjusting a flow rate of the cooling water that cools the combustion air and a flow rate of the cooling water that passes the combustion air without cooling.

According to the exhaust heat recovery method according to the present invention, the flow rate of the cooling water for cooling the combustion air is increased, and the flow rate of the cooling water that is allowed to pass without cooling the combustion air is reduced to exchange heat with the working fluid. The temperature of the cooling water to be increased. Therefore, even when the temperature of the cooling water is lowered, the operation is performed by appropriately adjusting the flow rate of the cooling water that cools the combustion air and the flow rate of the cooling water that passes without cooling the combustion air. The temperature of the cooling water heat exchanged with the fluid is adjusted to an appropriate temperature.
By doing in this way, even if it is a case where the temperature of cooling water falls, the exhaust heat recovery method which can maintain the calorie | heat amount recovered by heating cooling water can be provided.

  According to the present invention, even if the temperature of the cooling water discharged from the internal combustion engine is lowered, the exhaust heat recovery device and the exhaust heat recovery type capable of maintaining the amount of heat recovered by heating the cooling water A ship propulsion apparatus and a waste heat recovery method can be provided.

1 is a schematic configuration diagram of an exhaust heat recovery ship propulsion device according to a first embodiment of the present invention. It is a flowchart which shows the temperature adjustment operation | movement of cooling water. It is a graph which shows the scavenging air temperature with respect to the main engine load in the waste heat recovery type | formula ship propulsion apparatus shown in FIG. It is a graph which shows the calorie | heat amount of the scavenging air with respect to the main engine load in the waste heat recovery type | formula ship propulsion apparatus shown in FIG. It is a schematic block diagram of the waste heat recovery type ship propulsion apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the temperature adjustment operation | movement of cooling water. 6 is a graph showing a main engine exhaust gas temperature with respect to a main engine load in the exhaust heat recovery type ship propulsion device shown in FIG. 5. It is a graph which shows the steam generation amount in the composite boiler with respect to the main machine load in the waste heat recovery type ship propulsion apparatus shown in FIG.

[First Embodiment]
Hereinafter, an exhaust heat recovery type ship propulsion device 1 according to a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, an exhaust heat recovery type ship propulsion device 1 (exhaust heat recovery device) according to this embodiment includes a diesel engine (internal combustion engine) 3, a turbocharger (supercharger) 4, and an air cooler. 5, a cooling water flow path 7, a three-way valve (first flow rate adjustment valve) 8, an ORC system (power generation system) 2, and an exhaust heat recovery system 10.

The exhaust heat recovery type ship propulsion apparatus 1 according to the present embodiment uses the organic fluid (operation) of the ORC system 2 by exchanging heat of the cooling water of the diesel engine 3 that is a main engine (main engine) that generates the propulsion power of the ship. It is a device that transmits electricity to a fluid and generates electricity using an organic fluid. The exhaust heat recovery type marine vessel propulsion apparatus 1 of the present embodiment makes it possible to effectively recover and reuse the exhaust heat by using the exhaust heat of the cooling water of the diesel engine 3 for power generation.
Hereinafter, each part of the exhaust heat recovery type ship propulsion apparatus 1 according to the present embodiment will be described with reference to the drawings.

The diesel engine 3 is a main engine (main engine) that generates a propulsion force of a ship, and is an internal combustion engine that burns with scavenging air using at least one of fuel oil and fuel gas as main fuel.
The turbocharger 4 includes a turbine 4a that is driven by exhaust gas that is discharged when the diesel engine 3 burns main fuel, and a compressor 4b that compresses outside air by the rotational power of the turbine. The outside air compressed by the turbocharger 4 is supplied to the diesel engine 3 as scavenging air for combustion.

  The air cooler 5 is a device that cools the scavenging air supplied from the compressor 4 b of the turbocharger 4 to the diesel engine 3. The temperature of the scavenging air at the inlet of the air cooler 5 is in the range of about 50 ° C. to about 200 ° C. depending on the main engine load (load of the diesel engine 3 as the main engine) as shown by an example in FIG. . By cooling the scavenging air with the air cooler 5, the temperature of the scavenging air at the outlet of the air cooler 5 is maintained at about 40 ° C. regardless of the main engine load. Thus, by reducing the temperature of the scavenging air, the weight per unit volume of the scavenging air supplied to the diesel engine 3 can be increased.

  The air cooler 5 includes a first air cooling unit 5a disposed on the upstream side in the flow direction of the combustion air, and a second air cooling unit 5b disposed on the downstream side thereof. The 1st air cooling part 5a cools scavenging air by performing heat exchange with the cooling water of the diesel engine 3 supplied from the cooling water flow path 7, and the scavenging air supplied from the compressor 4b. The second air cooling unit 5b further cools the scavenged air by performing heat exchange between the fresh water cooled by seawater by a central cooler (not shown) and the scavenged air cooled by the first air cooling unit 5a. To do.

As shown in FIG. 1, the cooling water channel 7 is a channel that circulates cooling water in the order of a channel 71, a channel 72, a channel 73, a channel 74, a channel 75, a channel 76, and a channel 77. is there. The cooling water flow path 7 further includes a flow path 78 connected to a branch point D where the flow path 73 and the flow path 74 are connected.
The flow path 74 (first flow path) is a flow path that guides cooling water discharged from the diesel engine 3 without passing through the air cooler 5 to the evaporator 21 of the ORC system 2. The flow path 78 (second flow path) is a flow path that guides cooling water discharged from the diesel engine 3 through the air cooler 5 to the evaporator 21 of the ORC system 2.

  The three-way valve 8 is connected to the evaporator 21 via the flow rate (first flow rate) of cooling water guided to the evaporator 21 via the flow channel 74 (first flow channel) and the flow channel 78 (second flow channel). It is a valve that adjusts the flow rate (second flow rate) of the cooling water that is introduced. The three-way valve 8 can set the flow rate of the cooling water flowing from the flow path 74 to the flow path 75 to 0 and allow the entire amount of cooling water flowing through the flow path 73 to flow from the flow path 78 to the flow path 75. Further, the three-way valve 8 can set the flow rate of the cooling water flowing from the flow path 78 to the flow path 75 to 0, and allow the entire amount of cooling water flowing through the flow path 73 to flow from the flow path 74 to the flow path 75.

  The ORC system (Organic Rankine Cycle System) 2 has an evaporator 21 for exchanging heat between the cooling water circulating in the cooling water flow path 7 and the organic fluid, and the evaporator 21 generates power using the organic fluid exchanged with the cooling water. It is a system to do. The ORC system 2 can effectively recover the exhaust heat of the diesel engine 3 by using the cooling water to which the heat generated by the combustion of the diesel engine 3 is transmitted as a heat source.

  The ORC system 2 includes an organic fluid flow path 20 that circulates an organic fluid. As the organic fluid flowing through the organic fluid path, low molecular hydrocarbons such as isopentane, butane, and propane, and R134a and R245fa used as refrigerants can be used. The ORC system 2 includes an evaporator 21, a power turbine 22, an economizer 23, a condenser 24, and a circulation pump 25, which are connected by an organic fluid flow path 20 as shown in FIG. Yes.

  In the ORC system 2, the evaporator 21 evaporates the organic fluid by exchanging heat between the cooling water flowing through the flow path 75 and the organic fluid. The organic fluid evaporated by the evaporator 21 is guided to the power turbine 22 by the organic fluid flow path 20. The power turbine 22 is rotated by being supplied with rotational power by a gas phase organic fluid. A generator 27 is connected to the output shaft of the power turbine 22 via a speed reducer 26. Accordingly, power is generated by the generator 27 by the rotational power of the power turbine 22.

  The vapor-phase organic fluid that gives rotational power to the power turbine 22 is guided to the condenser 24 and is cooled by seawater, so that the vapor-phase organic fluid is condensed into a liquid-phase organic fluid. The liquid organic fluid is guided to the economizer 23 by the circulation pump 25. The economizer 23 performs heat exchange between the liquid-phase organic fluid led from the circulation pump 25 and the gas-phase organic fluid discharged from the power turbine 22, heats the liquid-phase organic fluid, and guides it to the evaporator 21. . As described above, the organic fluid of the ORC system 2 circulates in the organic fluid flow path 20 in the order of the evaporator 21, the power turbine 22, the condenser 24, the circulation pump 25, and the economizer 23.

Next, a mechanism for adjusting the flow rate of the cooling water circulating through the cooling water channel 7 will be described.
The exhaust heat recovery type ship propulsion apparatus 1 includes a control unit 9 shown in FIG. The controller 9 adjusts the flow rate of the cooling water circulating in the cooling water flow path 7 by adjusting the opening degree of the flow rate adjusting valves 81, 82, 83 and the three-way valves 84, 8, 87.

  The flow rate adjusting valves 81, 82, 83 are valves that adjust the flow rate of the cooling so as to guide a certain amount of cooling water of the diesel engine 3 discharged from the flow path 71 to a fresh water generator (not shown). Here, the fresh water generator uses the exhaust heat of the cooling water of the diesel engine 3 guided through the bypass passage 91 to heat the seawater taken from the outside of the ship and evaporate the heated seawater. It is an evaporation type (flash type) fresh water generator that produces fresh water. In order to make it possible to always produce a constant amount of fresh water, a constant amount of cooling water (for example, a flow rate of 70 t / h out of a flow rate of 140 t / h flowing through the flow path 71) is supplied to the fresh water generator. Led.

  The cooling water led to the fresh water generator is used to evaporate the seawater and then led to the flow path 72 via the bypass flow path 92. Thus, a certain amount of the exhaust heat of the cooling water of the diesel engine 3 is used as a heat source of the fresh water generator. On the other hand, another fixed amount (the flow rate of the cooling water that is not guided to the fresh water generator) of the exhaust water of the cooling water of the diesel engine 3 is guided to the flow path 72 via the flow rate adjustment valve 81.

The three-way valve 84 guides a part of the flow rate of the cooling water guided to the flow path 72 to the flow path 73 and guides the other part of the flow rate to the flow path 77 in which the three-way valve 87 and the circulation pump 88 are provided. It is. The three-way valve 84 can guide the entire amount of cooling water guided to the flow path 72 to the flow path 73, and can guide the total amount of cooling water guided to the flow path 72 to the flow path 77.
The control unit 9 detects the flow rate of the cooling water flowing through the flow path 73 by the flow meter 85 provided on the flow path 73 and adjusts the opening degree of the three-way valve 84.

  The cooling water guided to the flow path 73 branches into the flow path 74 and the flow path 78 at the branch point D. The downstream ends of the flow path 74 and the flow path 78 are connected to the three-way valve 8. The three-way valve 8 is a flow rate (first flow rate) of cooling water guided to the evaporator 21 via the flow path 74 (first flow path) among the cooling water flowing through the flow path 73 in accordance with an instruction from the control unit 9. The ratio between the flow rate) and the flow rate of cooling water (second flow rate) guided to the evaporator 21 via the flow path 78 (second flow path) is adjusted.

  A temperature sensor 86 (temperature detection unit) is provided in the flow path 75 on the downstream side of the three-way valve 8 to detect the temperature of the cooling water in a state where the cooling water flowing in from the flow path 74 and the flow path 78 is mixed. To do. As will be described later, the control unit 9 controls the three-way valve 8 so that the temperature detected by the temperature sensor 86 is equal to or higher than a predetermined temperature.

  The cooling water adjusted to be equal to or higher than the predetermined temperature passes through the evaporator 21 of the ORC system 2 and is then guided to the flow path 76. A downstream end of the flow path 76 is connected to a three-way valve 87. The three-way valve 87 guides cooling water flowing through the flow path 76 to a circulation pump 88 provided in the flow path 77. The three-way valve 87 is a flow rate of cooling water guided from the flow path 76 to the flow path 77 through the central cooler and cooling guided to the flow path 77 without going through the central cooler in accordance with an instruction from the control unit 9. It is possible to adjust the flow rate of water.

  The circulation pump 88 is a device that gives a flow rate to the cooling water so that the cooling water circulates in the cooling water flow path 7. The cooling water guided to the circulation pump 88 is guided again to the diesel engine 3 from the flow path 77 and used as cooling water for the diesel engine 3.

Next, an exhaust heat recovery system 10 that recovers and uses exhaust heat of exhaust gas (combustion gas) discharged from the diesel engine 3 and used as power for the turbocharger 4 will be described.
The exhaust heat recovery system 10 includes a composite boiler 101.

  In the composite boiler 101, high-temperature exhaust gas is guided from the turbocharger 4 through the flow path 102. The water sent to the composite boiler 101 evaporates by heat exchange with the exhaust gas, and the generated steam is sent to the heater 103 and used as a heat source for various devices (oil heater, tank heater, etc.). The steam used as a heat source in the heater 103 is collected in the atmospheric pressure drain tank 104.

The water in the atmospheric pressure drain tank 104 is sent out by the water supply pump 105 and guided to the composite boiler 101. The water level in the composite boiler 101 collected in the atmospheric pressure drain tank 104 is adjusted by a float switch (not shown) so as to maintain a constant water level.
As described above, the exhaust heat recovery system 10 recovers exhaust heat of exhaust gas (combustion gas) used as the power of the turbocharger 4 to generate steam, and various devices (oil heater, tank heater, etc.) It can be used as a heat source.

Next, with reference to FIG. 2, the temperature adjustment operation of the cooling water performed by the controller 9 adjusting the three-way valve 8 will be described. Each step shown in FIG. 2 is performed by the control unit 9 reading and executing a control program from a storage unit (not shown).
2 will be described with reference to FIGS. FIG. 3 is a graph showing the scavenging air temperature with respect to the main engine load, the solid line indicates the scavenging air temperature at the inlet of the air cooler 5, and the chain line indicates the scavenging air temperature at the outlet of the air cooler 5. FIG. 4 is a graph showing the amount of heat with respect to the main engine load, the solid line indicates the amount of heat provided by the scavenged air discharged from the turbocharger 4, and the chain line indicates the amount of heat provided by the cooling water discharged from the diesel engine 3.

In step S201, the control unit 9 determines whether the load of the main engine (diesel engine 3) is lower than the predetermined load. If the load is lower than the predetermined load, the control unit 9 proceeds to step S202. Proceed.
Here, the case where the load is lower than the predetermined load means, for example, a case where the main machine load is 60%. When the main machine load is 100%, the output is, for example, 13000 kW (rotation speed: 102.6 rpm). As shown in FIG. 4, when the main engine load is 60%, the amount of heat of the cooling water discharged from the diesel engine 3 is Q2 kW (about 1400 kW). As described above, a certain amount of heat (about 600 kW) included in the amount of heat of the cooling water is consumed as a heat source of the fresh water generator. As shown in FIG. 4, the amount of heat corresponding to (Q2-Q1) is consumed as the amount of heat for the fresh water generator. Accordingly, the amount of heat that can be used as the heat source of the ORC system 2 is Q1 kW (about 800 kW) when the main engine load is 60%.

When the amount of heat available as a heat source for the ORC system 2 is less than 800 kW, the temperature of the chilled water supplied to the ORC system 2 is lower than 85 ° C., and the ORC system 2 can generate the desired generated power (about 100 kW). Disappear. Therefore, when the load on the main engine is lower than the predetermined load, the control unit 9 adjusts the three-way valve 8 as described below to increase the temperature of the cooling water supplied to the ORC system 2.
As shown in FIG. 3 and FIG. 4, even if the main engine load is 60% or less, the temperature and the amount of heat of the scavenging air are sufficient (for example, at about 130 ° C. and about 1200 kW at the main engine load of 50%). ) By using scavenging air as a heat source, the temperature of the cooling water can be increased.

  In step S202 (temperature detection step), the control unit 9 refers to the detection value of the temperature sensor 86 and determines whether or not the temperature of the cooling water flowing through the flow path 75 is lower than a predetermined temperature (for example, 85 ° C.). . If it is determined that the temperature of the cooling water is lower than the predetermined temperature, it is necessary to increase the temperature of the cooling water, and thus the process proceeds to step S203. When it is not determined that the temperature of the cooling water is lower than the predetermined temperature, the process proceeds to step S204 because the temperature of the cooling water is sufficient.

In step S <b> 203, the control unit 9 adjusts the three-way valve 8 to reduce the flow rate (first flow rate) of the cooling water guided to the evaporator 21 via the flow path 74 and evaporate via the flow path 78. The flow rate (second flow rate) of the cooling water led to the vessel 21 is increased. The flow rate adjustment amount may be a previously fixed flow rate, or may be adjusted based on the difference between the detected value of the temperature sensor 86 and a predetermined temperature (for example, 85 ° C.).
Since the control unit 9 returns the process to step S201 again after step S203, the processes of step S201, step S202, and step S203 are repeated until the temperature of the cooling water becomes equal to or higher than the predetermined temperature.

When it is determined in step S201 that the temperature of the cooling water is equal to or higher than the predetermined temperature and the load on the main engine is equal to or higher than the predetermined load, the control unit 9 advances the process to step S204.
In step S204, the control unit 9 evaporates through the flow path 74 because the load of the diesel engine 3 as the main engine becomes equal to or higher than the predetermined load and the temperature of the cooling water supplied to the ORC system 2 becomes equal to or higher than the predetermined temperature. The flow rate (first flow rate) of the cooling water guided to the evaporator 21 is 100%, and the flow rate (second flow rate) of the cooling water guided to the evaporator 21 via the flow path 78 is 0%. By setting the second flow rate to 0%, the cooling water is not heated by the air cooler 5.

  As described above with reference to FIG. 2, the control unit 9 is configured such that the load of the diesel engine 3 as the main engine is lower than the predetermined load and the temperature of the cooling water supplied to the ORC system 2 does not exceed the predetermined temperature. The three-way valve 8 is adjusted to increase the temperature of the cooling water. Thereby, even when the load of the diesel engine 3 is low and the temperature of the cooling water discharged from the diesel engine 3 is low, the temperature of the cooling water supplied to the ORC system 2 is maintained at a predetermined temperature or higher. Can do.

The operation and effect of the exhaust heat recovery type ship propulsion device according to the present embodiment described above will be described.
According to the exhaust heat recovery type ship propulsion apparatus 1 (exhaust heat recovery power generation apparatus) according to the present embodiment, the cooling water guided to the flow path 74 (first flow path) is evaporated without being heated by the air cooler 5. The cooling water led to the vessel 21 (heat exchanger) and led to the channel 78 (second channel) is heated by the air cooler 5 and then led to the evaporator 21. The temperature of the cooling water guided to the evaporator 21 is decreased by decreasing the flow rate (first flow rate) of the cooling water guided to the flow path 74 and increasing the flow rate (second flow rate) of the cooling water guided to the flow path 78. To rise. Therefore, even when the temperature of the cooling water discharged from the diesel engine 3 (internal combustion engine) decreases, the flow rate of the cooling water guided to the flow path 74 and the flow rate of the cooling water guided to the flow path 78 are reduced in three directions. By appropriately adjusting with the valve 8 (first flow rate adjusting valve), the temperature of the cooling water led to the evaporator 21 is adjusted to an appropriate temperature.
By doing in this way, even if it is a case where the temperature of the cooling water discharged | emitted from the diesel engine 3 falls, cooling water is heated and the calorie | heat amount (electric power generation amount) which ORC system 2 (electric power generation system) collect | recovers is maintained. It is possible to provide the exhaust heat recovery type ship propulsion device 1 that can perform the above operation.

The exhaust heat recovery type ship propulsion apparatus 1 of the present embodiment is provided on the downstream side of the three-way valve 8, and includes a temperature sensor 86 (temperature detection unit) that detects the temperature of cooling water led from the three-way valve 8 to the evaporator 21. The three-way valve 8 adjusts the flow rate of the cooling water guided to the flow path 74 and the flow rate of the cooling water guided to the flow path 78 so that the temperature of the cooling water detected by the temperature sensor 86 is equal to or higher than a predetermined temperature. .
By doing in this way, the three-way valve 8 adjusts so that the temperature of the cooling water led from the downstream side of the three-way valve 8 to the evaporator 21 of the ORC system 2 becomes a predetermined temperature or more, and the ORC system 2 collects it. The amount of heat (power generation) can be maintained.

In the exhaust heat recovery type ship propulsion apparatus 1 of the present embodiment, the ORC system 2 is driven by the organic fluid (working fluid) evaporated by the evaporator 21, and the electric power is generated according to the rotation of the power turbine 22. And a generator 27 to be generated.
By doing in this way, the exhaust heat of the cooling water discharged | emitted from the diesel engine 3 can be transmitted to an organic fluid, it can be evaporated, and electric power generation can be performed with the evaporated organic fluid.

[Second Embodiment]
Next, an exhaust heat recovery type ship propulsion device 200 according to a second embodiment of the present invention will be described with reference to the drawings.
The second embodiment is a modification of the first embodiment, and is the same as the first embodiment unless otherwise described below. Below, the same code | symbol is attached | subjected about the structure same as 1st Embodiment, and those description is abbreviate | omitted.

  The exhaust heat recovery type ship propulsion apparatus 200 of the first embodiment uses steam generated by the composite boiler 101 only by the heater 103. On the other hand, the exhaust heat recovery type ship propulsion apparatus 200 according to the second embodiment uses steam generated by the composite boiler 101 in both the heater 103 and the heater 203 (auxiliary heat exchanger). The steam supplied to the heater 203 is used as a heat source for heating the cooling water flowing through the flow path 78 of the cooling water flow path 7.

Hereinafter, a mechanism for heating the cooling water flowing through the flow path 78 of the cooling water flow path 7 will be described.
As shown in FIG. 5, the steam in the composite boiler 101 can be supplied to both the heater 103 and the heater 203. The controller 9 adjusts the amount of steam supplied to each of the heater 103 and the heater 203 by adjusting the opening degree of the control valve 202.

The heater 203 circulates steam supplied from the control valve 202 therein, and heats the cooling water by exchanging heat between the steam and the cooling water flowing through the flow path 78. Steam used as a heat source that passes through the heater 203 and heats the cooling water is collected in the atmospheric pressure drain tank 104.
In this way, the control unit 9 supplies the steam in the composite boiler 101 to the heater 203 and adjusts the amount of steam supplied by the control valve 202, thereby cooling the coolant flowing through the flow path 78 of the cooling water flow path 7. Heat the water to the proper temperature.

Next, with reference to FIG. 6, the temperature adjustment operation of the cooling water performed by the controller 9 adjusting the three-way valve 8 and the control valve 202 will be described. Each step shown in FIG. 6 is performed by the control unit 9 reading and executing a control program from a storage unit (not shown).
6 will be described with reference to FIGS. FIG. 7 shows the main engine exhaust gas temperature (temperature of the combustion gas discharged from the diesel engine 3) with respect to the main engine load. FIG. 8 is a graph showing the amount of steam generated in the composite boiler 101 with respect to the main engine load.

In step S601, the control unit 9 determines whether or not the load on the main engine (diesel engine 3) is lower than the predetermined load. If the load is lower than the predetermined load, the control unit 9 proceeds to step S602; otherwise, the process proceeds to step S606. Proceed.
Here, the case where the load is lower than the predetermined load means, for example, a case where the main machine load is 60%. As described with reference to FIG. 4 in the first embodiment, the amount of heat available as the heat source of the ORC system 2 is Q1 kW (about 800 kW) when the main engine load is 60%.

  When the amount of heat available as a heat source for the ORC system 2 is less than 800 kW, the temperature of the chilled water supplied to the ORC system 2 is lower than 85 ° C., and the ORC system 2 can generate a desired generated power (about 100 kW). Disappear. Therefore, when the load on the main engine is lower than the predetermined load, the control unit 9 adjusts the three-way valve 8 and the control valve 202 as described below to increase the temperature of the cooling water supplied to the ORC system 2.

  As shown in FIG. 3 and FIG. 4 of the first embodiment, even if the main engine load is 60% or less, the temperature and the amount of heat of the scavenging air are sufficient (for example, about 50% main engine load) The temperature of the cooling water can be increased by using scavenging air as a heat source at about 130 kW at 130 ° C. As shown in FIGS. 7 and 8 of the present embodiment, as the main engine load decreases from about 60% to about 35%, the temperature of the exhaust gas discharged from the diesel engine 3 as the main engine rises. .

  This is because the combustion efficiency is deteriorated by lowering the load set in advance in consideration of the combustion efficiency, and as a result, exhaust gas having a large amount of heat is discharged. As the heat amount of the exhaust gas increases, as shown in FIG. 8, the steam generation amount generated by the composite boiler 101 increases as the main engine load decreases from about 60% to about 35%. As will be described below, the control valve 202 is adjusted to increase the temperature of the cooling water supplied to the ORC system 2 using the steam generated by the composite boiler 101 as a heat source of the cooling water.

  In step S602, the control unit 9 refers to the detection value of the temperature sensor 86 and determines whether or not the temperature of the cooling water flowing through the flow path 75 is lower than a predetermined temperature (for example, 85 ° C.). When it is determined that the temperature of the cooling water is lower than the predetermined temperature, it is necessary to increase the temperature of the cooling water, and thus the process proceeds to step S603. If it is not determined that the temperature of the cooling water is lower than the predetermined temperature, the process proceeds to step S606 because the temperature of the cooling water is sufficient.

In step S <b> 603, the control unit 9 causes the flow rate of the cooling water (second flow rate) guided to the evaporator 21 via the flow path 78 to be less than 100% of the flow rate with respect to the cooling water flowing through the flow path 73. If less than 100%, the process proceeds to step S604; otherwise, the process proceeds to step S605.
The case where the control unit determines NO in step S <b> 603 refers to the case where the entire amount of cooling water flowing through the flow path 73 flows through the flow path 78 via the air cooler 5. In this case, the flow rate of the cooling water flowing through the flow path 78 cannot be increased any more.

In step S <b> 604, the control unit 9 adjusts the three-way valve 8 to reduce the flow rate (first flow rate) of the cooling water guided to the evaporator 21 via the flow path 74 and evaporate via the flow path 78. The flow rate (second flow rate) of the cooling water led to the vessel 21 is increased. The flow rate adjustment amount may be a previously fixed flow rate, or may be adjusted based on the difference between the detected value of the temperature sensor 86 and a predetermined temperature (for example, 85 ° C.).
Since the control unit 9 proceeds to step S601 again after step S604, the processing from step S601 to step S604 is repeated until the temperature of the cooling water becomes equal to or higher than the predetermined temperature.

In step S605, the control unit 9 cannot further heat the cooling water using the air cooler 5 as a heat source, so that the flow rate (third flow rate) of the steam supplied from the evaporation drum 101a to the heater 203 is increased. Then, the control valve 202 is adjusted. The adjustment amount of the flow rate of the steam may be adjusted in advance, or may be adjusted based on the difference between the detected value of the temperature sensor 86 and a predetermined temperature (for example, 85 ° C.).
Since the control unit 9 proceeds to step S601 again after step S605, the processes from step S601 to step S603 and step S605 are repeated until the temperature of the cooling water becomes equal to or higher than the predetermined temperature.

When it is determined in step S601 that the temperature of the cooling water is equal to or higher than the predetermined temperature and the load on the main engine is equal to or higher than the predetermined load, the control unit 9 advances the process to step S606.
In step S604, the control unit 9 evaporates through the flow path 74 because the load of the diesel engine 3 as the main engine becomes equal to or higher than the predetermined load and the temperature of the cooling water supplied to the ORC system 2 becomes equal to or higher than the predetermined temperature. The flow rate (first flow rate) of the cooling water guided to the evaporator 21 is 100%, and the flow rate (second flow rate) of the cooling water guided to the evaporator 21 via the flow path 78 is 0%. By setting the second flow rate to 0%, the cooling water is not heated by the air cooler 5. Further, the controller 9 sets the flow rate (third flow rate) of the steam supplied from the evaporation drum 101a to the heater 203 to 0% so that the cooling water is not heated by the heater 203.

  As described above with reference to FIG. 6, the control unit 9 is configured such that the load of the diesel engine 3 as the main engine is lower than the predetermined load and the temperature of the cooling water supplied to the ORC system 2 does not exceed the predetermined temperature. Adjust the three-way valve 3 to increase the temperature of the cooling water. Further, if the temperature of the cooling water cannot be increased even after adjusting the three-way valve 3, the control valve 107 and the control valve 202 are adjusted to increase the temperature of the cooling water. Thereby, even when the load of the diesel engine 3 is low and the temperature of the cooling water discharged from the diesel engine 3 is low, the temperature of the cooling water supplied to the ORC system 2 is maintained at a predetermined temperature or higher. Can do.

The operation and effect of the exhaust heat recovery type ship propulsion device according to the present embodiment described above will be described.
The exhaust heat recovery type ship propulsion apparatus 200 according to the present embodiment is a composite boiler 101 that generates steam using the exhaust gas discharged from the turbocharger 4 as a heat source with respect to the exhaust heat recovery type ship propulsion apparatus 1 according to the first embodiment. And a heater 203 (auxiliary heat exchanger) for exchanging heat between the steam generated by the composite boiler 101 and the cooling water guided to the evaporator 21.
By doing in this way, even if the temperature of the cooling water discharged from the diesel engine 3 (internal combustion engine) is low and the temperature of the cooling water cannot be sufficiently maintained by heating with the air cooler 5, the heater 203 It becomes possible to maintain the temperature of the cooling water.

1,200 Waste heat recovery type ship propulsion device (exhaust heat recovery device)
2 ORC system (power generation system)
3 Diesel engine (internal combustion engine)
4 Turbocharger (supercharger)
4a Turbine 4b Compressor 5 Air cooler 5a 1st air cooling part 5b 2nd air cooling part 7 Cooling water flow path 8 Three-way valve (1st flow regulating valve)
9 Control unit 10 Waste heat recovery system 21 Evaporator (heat exchanger)
22 Power turbine (turbine)
27 Generator 74 Flow path (first flow path)
78 channel (second channel)
86 Temperature sensor (temperature detector)
101 Composite boiler 202 Control valve D Branch point

Claims (7)

An internal combustion engine;
A supercharger that is driven by exhaust gas discharged from the internal combustion engine, compresses the air, and supplies the compressed air to the internal combustion engine as combustion air;
An air cooler for cooling the combustion air supplied from the supercharger to the internal combustion engine;
A cooling water passage for circulating cooling water for cooling the internal combustion engine;
A heat exchanger for exchanging heat between the cooling water circulating in the cooling water flow path and a working fluid,
The cooling water flow path is
A first flow path for guiding the cooling water discharged from the internal combustion engine without passing through the air cooler to the heat exchanger;
A second flow path for guiding the cooling water discharged from the internal combustion engine through the air cooler to the heat exchanger,
A first flow rate of the cooling water guided to the heat exchanger via the first flow path and a second flow rate of the cooling water guided to the heat exchanger via the second flow path are adjusted. An exhaust heat recovery apparatus including a first flow rate adjustment valve. A temperature detection unit that is provided on the downstream side of the first flow rate adjustment valve and detects the temperature of the cooling water led from the first flow rate adjustment valve to the heat exchanger;
2. The exhaust heat recovery according to claim 1, wherein the first flow rate adjusting valve adjusts the first flow rate and the second flow rate so that a temperature of the cooling water detected by the temperature detection unit is equal to or higher than a predetermined temperature. apparatus. An exhaust heat recovery system for recovering heat of the exhaust gas that has passed through the supercharger;
The exhaust heat recovery apparatus according to claim 2, further comprising an auxiliary heat exchanger that performs heat exchange between the heat recovered by the exhaust heat recovery system and the cooling water guided to the heat exchanger. A second flow rate adjusting valve for adjusting the flow rate of the steam guided to the auxiliary heat exchanger;
The exhaust heat recovery apparatus according to claim 3, wherein the second flow rate adjustment valve adjusts the flow rate of the steam so that the temperature of the cooling water detected by the temperature detection unit is equal to or higher than a predetermined temperature. The internal combustion engine is a main engine that generates a propulsive force of a ship,
An exhaust heat recovery type ship propulsion device comprising the exhaust heat recovery device according to any one of claims 1 to 4. A process of exhausting exhaust gas;
Compressing air with the exhaust gas to generate combustion air;
Cooling the combustion air with cooling water;
Heat exchange of the cooling water with the working fluid;
An exhaust heat recovery method comprising a step of adjusting a flow rate of the cooling water that cools the combustion air and a flow rate of the cooling water that passes the combustion air without cooling. Detecting the temperature of the cooling water before exchanging heat with the working fluid,
The adjusting step is performed without cooling the combustion air and the flow rate of the cooling water that cools the combustion air so that the temperature of the cooling water detected by the step of detecting the temperature is equal to or higher than a predetermined temperature. The exhaust heat recovery method according to claim 6, wherein a flow rate of the cooling water to be passed is adjusted.

Images