KR102553603B1 - Energy recovery device, its control method, and ship equipped with the same - Google Patents

Abstract

A supercharger 20, a power turbine generator 30 and a control device 50 are provided. The power turbine generator 30 is provided in the power generation line 12 and generates power by energy of exhaust gas discharged from the exhaust manifold M1. A power generation control valve V1 is provided in the power generation line 12 to control the flow rate of exhaust gas supplied from the exhaust manifold M1 to the power turbine generator 30. An exhaust valve V2 is provided in the exhaust line 14 to exhaust the exhaust gas from the exhaust manifold M1 to the outside. The control device 50 controls the power generation control valve V1 and the exhaust valve V2.

Description

Energy recovery device, its control method, and ship equipped with the same

The present invention relates to an energy recovery device capable of responding to the tertiary NOx regulation, a control method thereof, and a ship equipped with the same.

Regulations by the International Maritime Organization on air pollutants emitted from ships become stricter every year, and in the tertiary NOx regulation (NOx　Tier　III, hereinafter referred to as the tertiary regulation), it is obligatory to reduce 80% from the 1st regulation value there is.

In order to cope with this tertiary regulation, an exhaust gas recirculation device (hereinafter referred to as EGR) may be employed as a nitrogen oxide removal device of a diesel main engine.

However, in a ship equipped with EGR, a large amount of surplus exhaust gas is generated in a sea area to which the tertiary regulation is not applied (non-regulation sea area), and energy efficiency is lowered.

Therefore, as a means for recovering exhaust gas energy, for example, Patent Literature 1 is disclosed.

The "exhaust gas energy recovery device of an engine" of Patent Document 1 includes an exhaust turbine supercharger, a power turbine generator, an exhaust gas recirculation device, and an exhaust pipe. The exhaust pipe exhausts exhaust gas from the exhaust manifold to the outside via the turbine unit of the exhaust turbine supercharger and the power turbine generator.

Japanese Unexamined Patent Publication No. 2014-152763

In the apparatus of Patent Literature 1, exhaust gas is exhausted from the exhaust manifold to the outside via the turbine unit of the exhaust turbine supercharger (hereinafter referred to as a supercharger) and the power turbine generator, so that the entire amount of the exhaust gas flowing into the supercharger is the power turbine enters the generator. For this reason, there were the following problems.

(1) Since the entire amount of exhaust gas from the supercharger flows into the power turbine generator, the power turbine generator becomes large.

(2) Since the exhaust gas is reduced in pressure by the supercharger, the power generation output by the power turbine generator is small.

(3) Since the entire amount of exhaust gas from the supercharger flows into the power turbine generator, the power turbine generator cannot be stopped alone.

(4) The back pressure of the supercharger increases due to the power turbine generator, and the performance of the supercharger deteriorates.

In addition, when excess exhaust gas is discharged to the outside by providing a bypass line in the supercharger, the amount of exhaust gas energy cannot be recovered. In particular, exhaust gas energy of a large amount of excess exhaust gas generated when the exhaust gas recirculation device is stopped or its throughput is reduced cannot be recovered.

The present invention was conceived to solve the above problems. That is, an object of the present invention is to provide an energy recovery device capable of efficiently recovering high-pressure exhaust gas energy with a small-sized power turbine generator, a control method thereof, and a ship equipped with the same, while preventing deterioration of supercharger performance.

According to the present invention, the supercharging line, the power generation line and the exhaust line each independently connected to the exhaust manifold of the engine;

a supercharger provided in the supercharging line to compress intake air by energy of the exhaust gas discharged from the exhaust manifold and to supply the compressed air to the scavenging manifold of the engine;

a power turbine generator provided in the power generation line and generating power by energy of the exhaust gas discharged from the exhaust manifold;

a power generation control valve provided in the power generation line to control a flow rate of exhaust gas supplied from the exhaust manifold to the power turbine generator;

an exhaust valve provided in the exhaust line to exhaust exhaust gas from the exhaust manifold to the outside; and

a control device for controlling the power generation control valve and the exhaust valve;

The control device stores a lower limit pressure and a relief pressure within an appropriate range of the scavenging pressure in the scavenging manifold;

(A) closing both the power generation control valve and the exhaust valve when the scavenging pressure is less than the lower limit pressure;

(B) controlling the power generation output of the power turbine generator by opening the power generation control valve when the scavenging pressure is equal to or greater than the lower limit pressure;

(C) When the scavenging pressure is equal to or higher than the relief pressure, the power generation control valve is opened to control the power generation output of the power turbine generator, and the exhaust valve is opened to depressurize the exhaust manifold. .

In addition, according to the present invention, as a control method of the energy recovery device,

storing a lower limit pressure and a relief pressure within an appropriate range of the scavenging pressure in the scavenging manifold in the control device;

Detecting the scavenging pressure during operation of the engine and comparing it with the lower limit pressure and the relief pressure;

closing both the power generation control valve and the exhaust valve when the scavenging pressure is less than the lower limit pressure;

Controlling the power generation output of the power turbine generator by opening the power generation control valve when the scavenging pressure is equal to or greater than the lower limit pressure;

When the scavenging pressure is equal to or greater than the relief pressure, the power generation control valve is opened to control the power generation output of the power turbine generator, and the exhaust valve is opened to depressurize the exhaust manifold. .

Further, according to the present invention, a ship equipped with the energy recovery device is provided.

According to the present invention, the supercharging line, the power generation line and the exhaust line are each independently connected to the exhaust manifold, the supercharger is installed in the supercharging line, and the power turbine generator is installed in the power generation line.

Therefore, since the exhaust gas of the supercharger is directly exhausted to the outside without passing through the power turbine generator, the back pressure of the supercharger does not increase and performance degradation of the supercharger can be prevented.

In addition, since the power turbine generator does not use the exhaust gas that has passed through the supercharger, it can operate independently of the supercharger and can be stopped independently. In addition, since the throughput of the power turbine generator can be set regardless of the amount of exhaust gas flowing into the supercharger, the power turbine generator can be downsized.

In addition, since the control device controls the power generation output of the power turbine generator by opening the power generation control valve when the control device is above the lower limit pressure within the appropriate range of the scavenging pressure, it is possible to efficiently recover the high-pressure exhaust gas energy conventionally useless. .

1 is an overall configuration diagram of an energy recovery device according to the present invention.
2 is an overall flowchart of the control method according to the present invention.
3A is a relationship diagram between a main engine load factor and an exhaust gas amount in Patent Document 1;
3B is a relationship diagram between the main engine load factor and the exhaust gas temperature in Patent Document 1;
3C is a relationship diagram between the main engine load factor and PT output in Patent Document 1;
Figure 4a is a relationship between the main engine load factor and PT output of the present invention.
4B is a relationship diagram between the main engine load factor and the surplus exhaust gas amount when the PTG is stopped according to the present invention.
4C is a diagram showing the relationship between the main engine load factor and the passage flow rate of the power generation control valve and the exhaust valve during PTG operation according to the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. On the other hand, the same reference numerals are attached to common parts in each drawing, and redundant explanations are omitted.

1 is an overall configuration diagram of an energy recovery device 100 according to the present invention.

In this figure, the energy recovery device 100 includes a charge line 10, a power generation line 12, an exhaust line 14, a supercharger 20, a power turbine generator 30 and a control device 50. .

The charge line 10 , the power generation line 12 , and the exhaust line 14 are pipe lines each independently connected to the exhaust manifold M1 of the engine 1 .

The engine 1 is the ship's main engine, in this example a diesel engine. Hereinafter, engine 1 is simply referred to as "main engine".

The load data of the engine 1 is input to the control device 50 in real time. As the load data, for example, shaft output, fuel input amount index, scavenging pressure, supercharger rotational speed, or numerical values calculated from a plurality of numerical values among these are used.

The supercharger 20 is provided in the supercharging line 10 and has a turbine 20a and a compressor 20b connected to each other, and the energy of the exhaust gas rotates the turbine 20a at a high speed to rotate the compressor 20b at a high speed, The intake air supplied from the outside is compressed by the compressor 20b.

The supercharger 20 is provided with sensors (not shown) that detect its rotational speed, inlet pressure, and inlet temperature, and their detection data is input to the control device 50 in real time.

The supercharging line 10 has an exhaust gas inlet pipe 10a, an exhaust gas outlet pipe 10b, an intake inlet pipe 10c, and an intake outlet pipe 10d.

The exhaust gas inlet pipe 10a communicates the exhaust manifold M1 and the inlet of the turbine 20a. The exhaust gas outlet pipe 10b communicates the outlet of the turbine 20a and an external exhaust gas discharge unit (eg, a stack). The intake inlet pipe 10c communicates the inlet of the compressor 20b with an external intake unit (eg, air filter). The intake outlet pipe 10d communicates the outlet of the compressor 20b and the scavenging manifold M2 of the engine 1.

With the configuration described above, the supercharger 20 compresses the intake air with the energy of the exhaust gas discharged from the exhaust manifold M1 and supplies it to the scavenging manifold M2 of the engine 1 .

A power turbine generator 30 (hereinafter referred to as PTG) is provided in the power generation line 12 and has a power turbine 30a, a speed reducer 30b and a generator 30c. The power turbine 30a is rotated at high speed by the energy of the exhaust gas, and the reduction gear 30b decelerates the rotation to drive the generator 30c to rotate, so the generator 30c generates electric power. The generator 30c may be a synchronous generator or an induction generator.

The power generation line 12 has an exhaust gas supply pipe 12a and an exhaust gas discharge pipe 12b.

With this configuration, the power turbine generator 30 (PTG) generates electricity by the energy of the exhaust gas discharged from the exhaust manifold M1.

In this example, the PTG further includes a shaft brake 30d that brakes the rotation of the power turbine 30a.

In Fig. 1, a power generation control valve V1 is provided in the power generation line 12 to control the flow rate of exhaust gas supplied from the exhaust manifold M1 to the PTG. The power generation control valve V1 is preferably a remotely controllable flow control valve.

The exhaust line 14 communicates the exhaust manifold M1 and an external exhaust gas discharge unit (eg, a stack).

An exhaust valve V2 is provided in the exhaust line 14 to exhaust the exhaust gas from the exhaust manifold M1 to the outside. The exhaust valve V2 is preferably a remotely controllable flow control valve, but may be a remotely controllable on-off valve (eg, a butterfly valve).

The control device 50 controls the power generation control valve V1 and the exhaust valve V2. A pressure detector 2 for detecting a scavenging pressure is provided in the scavenging manifold M2, and the detected scavenging pressure is input to the control device 50.

The control device 50 stores the lower limit pressure PL and the relief pressure PH within an appropriate range of the scavenging pressure in the scavenging manifold, and performs the following control.

(A) When the scavenging pressure is less than the lower limit pressure PL, both the power generation control valve V1 and the exhaust valve V2 are closed.

(B) When the scavenging pressure is higher than the lower limit pressure (PL), the power generation control valve (V1) is opened to control the power generation output of the PTG.

(C) When the scavenging pressure is higher than the relief pressure (PH), the exhaust valve (V2) is opened to depressurize the exhaust manifold (M1).

In FIG. 1 , the energy recovery device 100 further includes an exhaust gas recirculation line 16 and an exhaust gas recirculation device 40 .

The exhaust gas recirculation line 16 has an exhaust gas inlet pipe 16a and an exhaust gas outlet pipe 16b. An inlet flow control valve V3 and an outlet flow control valve V4 are respectively provided in the exhaust gas inlet pipe 16a and the exhaust gas outlet pipe 16b to control the flow rate of exhaust gas flowing therethrough.

An exhaust gas recirculation device 40 (hereinafter referred to as EGR) is provided between the exhaust manifold M1 and the scavenging manifold M2, and has, for example, a sprayer, a cooler, and a blower, and includes an exhaust manifold M1 ) is supplied to the scavenging manifold (M2).

With this configuration, exhaust gas is taken out from the exhaust manifold M1, treated by EGR, and returned to the scavenging manifold M2, thereby lowering the oxygen concentration of combustion air and reducing NOx production.

In order to comply with the tertiary regulation by the International Maritime Organization, installation of the exhaust gas recirculation device 40 (EGR) is indispensable. However, the sea area (regulation sea area) to which the tertiary regulation is applied is limited to, for example, the vicinity of the coast of the United States or Canada, and is not applied in most other sea areas (non-regulation sea area).

Therefore, by using EGR in the regulated sea area and stopping and operating the EGR in the non-regulated sea area, it is possible to increase the energy efficiency of the vessel while satisfying the tertiary regulation.

For this reason, the control device 50 of the present invention has a clean operation mode and a power generation operation mode.

In the clean operation mode, the exhaust gas recirculation device 40 (EGR) is operated so that the concentration of NOx in the exhaust gas is equal to or less than the first threshold value. A 1st threshold value is set suitably for the 3rd regulation, for example. The clean operation mode is preferably used in a regulated sea where the tertiary regulation is applied.

In the power generation operation mode, the circulation amount of exhaust gas by EGR is reduced, and surplus exhaust gas is supplied to PTG to generate power. The power generation operation mode is preferably used in an unregulated sea area. Meanwhile, it is okay to completely stop the EGR in the power generation operation mode.

The openings of the inlet flow control valve V3 and the outlet flow control valve V4 are controlled in the clean operation mode and the power generation operation mode.

2 is an overall flowchart of the control method of the energy recovery device 100 according to the present invention.

In this figure, the control method of the present invention has each step (process) of S1 to S5 using the energy recovery device 100 described above. Steps S1 to S5 are repeatedly performed while the engine 1 is running.

In step S1, the control device 50 stores the lower limit pressure PL and the relief pressure PH within the appropriate range of the scavenging pressure in the scavenging manifold M2. The appropriate range of the scavenging pressure is appropriately changed according to the operating state of the engine 1 . Further, for example, the lower limit pressure PL is set to the lower limit of the appropriate range of scavenging pressure, and the relief pressure PH is set to a pressure higher than the lower limit pressure PL and lower than the upper limit of the appropriate range.

In step S2, the scavenging pressure is detected during operation of the engine 1 and compared with the lower limit pressure PL and the relief pressure PH.

In step S3, when the scavenging pressure is less than the lower limit pressure PL, both the power generation control valve V1 and the exhaust valve V2 are closed. Accordingly, the exhaust gas exhausted to the outside from the exhaust manifold M1 can be eliminated, and the entire amount of the exhaust gas can be supplied to the scavenging manifold M2.

In step S4, when the scavenging pressure is equal to or higher than the lower limit pressure PL, the power generation control valve V1 is opened to control the power generation output of the PTG 30. Accordingly, it is possible to generate power by surplus exhaust gas energy while maintaining the scavenging pressure in an appropriate range. The generated electricity can be effectively used on board.

On the other hand, in step S4, it is determined that the PTG can be started when any one or more of the load of the engine 1, the scavenging pressure, the number of revolutions of the supercharger 20, the inlet pressure, or the inlet temperature is equal to or greater than a predetermined set value.

In addition, when the PTG starts, the power generation control valve V1 is opened, and in addition, any one or a plurality of the load of the engine 1, the scavenging pressure, the number of revolutions of the supercharger 20, the inlet pressure, or the inlet temperature It is better to adjust the opening of the power generation control valve V1 so that it does not fall below the set value.

In addition, when the PTG stops, the exhaust valve V2 is opened, and then the power generation control valve V1 is closed, thereby preventing the PTG from overrunning.

In addition, when the PTG is cut off by overcurrent, the power generation control valve V1 is completely closed at the same time as the exhaust valve V2 is opened, and the rotation of the power turbine 30a of the PTG is braked by the shaft brake 30d. .

In step S5, when the scavenging pressure is equal to or higher than the relief pressure (PH), the exhaust valve V2 is opened to open the exhaust manifold M1 while controlling the power generation output of the PTG 30 by opening the power generation control valve V1. depressurize Accordingly, the scavenging pressure can be lowered to an appropriate range.

On the other hand, when the exhaust valve V2 is a flow control valve, when the scavenging pressure is equal to or higher than the relief pressure PH, any one of the load of the engine 1, the scavenging pressure, the number of revolutions of the supercharger 20, the inlet pressure, and the inlet temperature It is preferable to adjust the opening degree of the exhaust valve V2 so that one or more does not fall below a predetermined set value.

The above-described control of steps S1 to S5 is preferably performed in both the clean operation mode and the power generation operation mode.

That is, as long as surplus exhaust gas is generated even in the clean operation mode, power generation is generated in the PTG 30 by opening the power generation control valve V1. In this way, the generated power can be effectively used on board.

3A to 3C are performance characteristics of the energy recovery device of Patent Document 1;

3A is a relationship diagram between a main engine load factor and an exhaust gas amount. The amount of exhaust gas increases almost in proportion to the increase in the main engine load factor. The commercial area of the main engine is, for example, 75 to 85% indicated by oblique lines in the drawing.

3B is a relationship diagram between the main engine load factor and the exhaust gas temperature. The exhaust gas temperature depends on the characteristics of the supercharger (20). That is, the exhaust gas temperature is not proportional to the main engine load factor because the supercharger efficiency is usually selected to be the maximum value near the normal power output.

The exhaust gas temperature generally rises from low load to medium load, becomes constant with an increase in turbocharger efficiency in the heavy load range, and rises dramatically in the high load range by bypassing the turbocharger 20.

3C is a relationship diagram between the main engine load factor and the PT output (output of the power turbine generator 30).

From the characteristics of FIGS. 3A and 3B, when the main engine load ratio exceeds the commercial range, the rise rate of the PT output increases as indicated by the broken ellipse in FIG. 3C. Due to its characteristics, the output of the PTG increases when the gas temperature increases, so in Patent Document 1, it is necessary to set the rated capacity of the PTG according to the 100% load of the main engine.

However, the frequency of operating the main engine at a load exceeding the commercial range is generally low, and rather, it is often operated at a load of about 40 to 70% lower than the commercial range due to reduced speed sailing. Therefore, in the PTG set according to the 100% load of the main engine as in Patent Document 1, the efficiency of the PTG is greatly reduced at a part load with high use frequency.

In addition, when an induction generator other than a synchronous generator is employed for the generator 30c of the PTG, since the PTG cannot operate independently, it is necessary to operate in parallel with a diesel generator. In this case, when the PTG is tripped (cut off), the diesel generator operating in parallel needs to generate extra power from the power generated by the PTG. The required capacity of the generator increases.

In the case of providing the EGR, as a characteristic of the EGR, since a certain amount of exhaust gas generated in the main engine returns to the intake air side during EGR operation, this amount of exhaust gas bypasses the supercharger. Since the operation amount of the supercharger is reduced by the bypass amount, the scavenging pressure is lowered in the tertiary regulation mode, resulting in deterioration in fuel economy. In order to compensate for this and suppress deterioration in fuel consumption, it is necessary to increase the size (rated capacity) of the supercharger.

However, if the size of the supercharger is increased, the supercharger becomes too large in the secondary regulation mode. That is, in the secondary regulation mode, exhaust gas energy is excessive with respect to the selected supercharger.

4A to 4C are characteristic diagrams showing the performance of the energy recovery device 100 of the present invention.

Figure 4a is a relationship between the main engine load factor and PT output in the present invention. In the present invention, the rated output of the PTG is set according to a load lower than the commercial area of the main engine. By this setting, the following effects can be obtained.

(1) PTG efficiency can be increased in partial load operation of the main engine.

(2) Since the rating of PTG is lowered, the cost of PTG can be lowered.

(3) Optimization of the capacity of diesel generators requiring parallel operation can be achieved.

FIG. 4B is a diagram showing the relationship between the main engine load factor and the surplus exhaust gas amount when the PTG is stopped in FIG. 1 .

In general, as the load on the main engine increases, the amount of surplus exhaust gas also increases.

Fig. 4C is a relationship diagram between the main engine load factor and the passage flow rate of the power generation control valve V1 and the exhaust valve V2 during PTG operation.

In the load region below the normal load region, when the scavenging pressure is equal to or greater than the lower limit pressure PL, the generation control valve V1 is opened to control the generation output of the PTG. In addition, the opening of the power generation control valve V1 is adjusted so that the scavenging pressure of the main engine is in an appropriate range (between the lower limit and the upper limit).

In general, since the scavenging pressure increases as the load of the main engine increases, the degree of opening of the power generation control valve V1 also increases.

Next, since the PTG is set to have a rated output in the vicinity of the normal load range, when the main engine load rises and the output of the PTG reaches the rated output, the power generation control valve V1 is turned on so that no more exhaust gas flows to the PTG. The degree of opening is adjusted.

On the other hand, when the scavenging pressure is equal to or higher than the predetermined relief pressure (PH), the exhaust valve (V2) is opened to depressurize the exhaust manifold (M1). For this reason, the scavenging pressure is less than the relief pressure (PH) at a load lower than the normal range, and the exhaust valve V2 is all closed.

At a load above the normal range, the PTG output reaches the rated value, and surplus gas that cannot be completely recovered from the PTG is generated and the scavenging pressure rises, so the scavenging pressure becomes higher than the relief pressure (PH) and the exhaust valve (V2) opens and the exhaust gas is discharged to the outside, and the exhaust manifold (M1) is depressurized.

In particular, when EGR is provided, it is expected that a large amount of exhaust gas energy remains in the secondary regulation mode, and this energy can be effectively used in the present invention.

As described above, in the present invention, when EGR is mounted to conform to the tertiary regulation, the supercharger 20 secures sufficient scavenging pressure in the tertiary regulation mode and generates excess exhaust gas in the secondary regulation mode. It selects, and also equips with the power turbine generator 30 (PTG). The PTG can recover the energy of surplus exhaust gas generated in large quantities when driving in the secondary regulation mode.

According to the present invention, since the size of the supercharger is large in a ship to which EGR is applied, the surplus exhaust gas energy discarded in the secondary regulation mode can be effectively used as power, and the overall thermal efficiency of the ship equipped with it can be increased.

As described above, in the present invention, in a ship corresponding to the tertiary regulation, the main engine is provided with a supercharger 20, a power turbine generator 30 (PTG), and an exhaust gas recirculation device 40 (EGR). The supercharger 20 secures sufficient scavenging pressure in an operation mode that satisfies the tertiary regulation (third regulation mode), and in the NOx secondary regulation (NOx Tier II, hereinafter referred to as secondary regulation), surplus exhaust gas energy selected to occur. Excess exhaust gas energy generated in an operation mode that satisfies the secondary regulation (secondary regulation mode) is recovered by the PTG.

The position of the power generation control valve V1 described above is preferably set to the starboard side or the stern side of the exhaust manifold M1. In the case of the starboard side, the exhaust gas discharge pipe 14b at the PTG outlet is in a position where it is easy to return to the main engine exhaust gas pipe. Further, in the case of the stern side, it is easy to support the exhaust gas bypass pipe, and there is an advantage that it is easy to secure a place to mount the PTG on the stern side of the ship.

The exhaust valve V2 is controlled to open at high speed when the power turbine generator 30 (PTG) trips the ACB (low pressure air circuit breaker).

In addition, preferably, the shaft brake 30d is operated to prevent the PTG from over-rotating when the ACB trips.

Other controls by the control device 50 are as follows.

(1) When selecting the secondary regulation mode, the PTG is enabled to start when any one or a plurality of conditions are satisfied among the load of the main engine, the scavenging pressure, the number of revolutions of the supercharger 20, the inlet pressure, or the inlet temperature.

(2) When the PTG starts, the power generation control valve V1 opens and the exhaust valve V2 completely closes. At this time, one or more of the load, scavenging pressure, rotation speed of the supercharger 20, inlet pressure, or inlet temperature of the main engine is then monitored so that the power generation control valve V1 does not fall below a predetermined set value Opening of the control valve V1 It is good to adjust the degree.

Further, in a preferable valve operation sequence, first, the power generation control valve V1 is opened, and the exhaust valve V2 is completely closed in response to the opening signal.

(3) When the PTG is stopped, the exhaust valve V2 is opened and the power generation control valve V1 is entirely closed. In a preferable valve operation sequence, the exhaust valve V2 is first opened, and the power generation control valve V1 is closed in response to the opening signal. A normal trip operation performs this control.

(4) When the PTG trips the ACB, the exhaust valve V2 is opened and the power generation control valve V1 is closed. At this time, preferably, the exhaust valve V2 and the power generation control valve V1 simultaneously operate at high speed. In addition, when the shaft brake 30d is provided, the shaft brake 30d operates simultaneously with the PTG trip to prevent over-rotation of the power turbine 30a.

On the other hand, when the power generation control valve V1 is completely closed, it is preferable to release the operation of the axial brake 30d to prevent overload of the axial brake 30d.

According to the embodiment of the present invention described above, the supercharging line 10, the exhaust line 14 and the power generation line 12 are each independently connected to the exhaust manifold M1, and the supercharger 20 is the supercharging line 10 ), and the power turbine generator 30 is installed in the power generation line 12.

Therefore, since the exhaust gas of the supercharger 20 is directly exhausted to the outside without passing through the power turbine generator 30, the back pressure of the supercharger 20 does not increase and the performance of the supercharger 20 can be prevented from being deteriorated.

In addition, since the power turbine generator 30 does not use the exhaust gas that has passed through the supercharger 20, it can independently operate separately from the supercharger 20 and can be stopped independently. In addition, since the throughput of the power turbine generator 30 can be set regardless of the amount of exhaust gas flowing into the supercharger 20, the power turbine generator 30 can be downsized.

In addition, since the control device 50 controls the power generation output of the power turbine generator 30 by opening the power generation control valve V1 when the scavenging pressure is equal to or higher than the lower limit pressure PL within an appropriate range, the exhaust is conventionally useless. It is possible to efficiently recover the high-pressure exhaust gas energy that was present.

On the other hand, the present invention is not limited to the above-described embodiment, and various changes are possible without departing from the gist of the present invention.

1: engine (main organ) 2: pressure detector
10 supercharging line 10a exhaust gas inlet pipe
10b: Exhaust gas outlet pipe 10c: Intake inlet pipe
10d: intake air outlet pipe 12: power generation line
12a: exhaust gas supply pipe 12b: exhaust gas discharge pipe
14 exhaust line 16 exhaust gas recirculation line
16a: exhaust gas inlet pipe 16b: exhaust gas outlet pipe
20: supercharger 20a: turbine
20b: pressure 30: power turbine generator (PTG)
30a: power turbine 30b: reducer
30c: generator 30d: axis brake
40: exhaust gas recirculation device 50: control device
100: energy recovery device M1: exhaust manifold
M2: scavenging manifold PL: lower limit pressure
PH: relief pressure V1: power generation control valve
V2: exhaust valve

Claims (10)

a charge line, a power generation line, and an exhaust line each independently connected to an exhaust manifold of the engine;
a supercharger provided in the supercharging line to compress intake air by energy of the exhaust gas discharged from the exhaust manifold and to supply the compressed air to the scavenging manifold of the engine;
a power turbine generator provided in the power generation line and generating power by energy of the exhaust gas discharged from the exhaust manifold;
a power generation control valve provided in the power generation line to control a flow rate of exhaust gas supplied from the exhaust manifold to the power turbine generator;
an exhaust valve provided in the exhaust line to exhaust exhaust gas from the exhaust manifold to the outside; and
A control method of an energy recovery device having a control device for controlling the power generation control valve and the exhaust valve,
storing a lower limit pressure and a relief pressure within an appropriate range of a scavenging pressure in the scavenging manifold in the control device;
Detecting the scavenging pressure during operation of the engine and comparing it with the lower limit pressure and the relief pressure;
closing both the power generation control valve and the exhaust valve when the scavenging pressure is less than the lower limit pressure;
When the scavenging pressure is equal to or greater than the lower limit pressure, the power generation control valve is opened to control the power generation output of the power turbine generator;
When the scavenging pressure is equal to or greater than the relief pressure, the power generation control valve is opened to control the power generation output of the power turbine generator, and the exhaust valve is opened to depressurize the exhaust manifold;
When the power turbine generator is cut off by overcurrent, the exhaust valve is fully opened and the power generation control valve is fully closed at the same time, and the shaft brake brakes the rotation of the turbine of the power turbine generator. control method. According to claim 1,
A control method of an energy recovery device that determines that the power turbine generator can be started when any one or a plurality of the load of the engine, the scavenging pressure, the number of revolutions of the supercharger, the inlet pressure, or the inlet temperature is greater than a predetermined set value. . According to claim 1,
A control method of an energy recovery device, wherein the exhaust valve is opened when the power turbine generator is stopped, and then the power generation control valve is closed. According to claim 1,
When the scavenging pressure is greater than or equal to the relief pressure, adjust the opening of the exhaust valve so that one or more of the load of the engine, the scavenging pressure, the number of revolutions of the supercharger, the inlet pressure, and the inlet temperature do not fall below a predetermined set value A control method of an energy recovery device.
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