JPH0372807B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a marine power plant.

Some conventional plants of this type have a generator connected directly or via gears to the ship's main propulsion engine (hereinafter referred to as the main engine), and the main engine directly drives the generator to supply power to the ship's load. Such plants have the disadvantage that they cannot generate electricity when the main engine is stopped or rotating at low speed. In addition, since the sailing speed of a ship is normally adjusted by changing the rotation speed of the main engine, the output frequency will fluctuate if this is done, so in order to keep this constant, a variable speed joint is installed between the main engine and the generator. There are some that insert a synchronous generator or supply the output of a synchronous generator as a constant frequency output via a frequency converter.
Such a device has the disadvantage of high cost. Some frequency converters use thyristors, but these generally have the disadvantage of not being able to supply reactive power.

Therefore, in order to eliminate the above drawbacks, there is an exhaust gas turbo power generation plant that uses an exhaust gas economizer to recover the exhaust heat contained in the exhaust gas from the main engine in the form of steam, and uses this steam to drive a turbo generator. Conventional exhaust gas turbo power plants have the following drawbacks.

In other words, (1) In general, the capacity of the exhaust gas turbo generator is considered to be the one that can supply the maximum onboard power during normal navigation, while the amount of steam generated by the exhaust gas economizer depends on changes in sea conditions, weather, dirt on the heat exchanger, etc. over time. Taking into account changes, the amount of steam that can be generated at all times during navigation is set to match the capacity of the exhaust gas turbo generator.

Therefore, the average power demand that occurs during normal navigation is generally much lower than the generator capacity, and in this case, the amount of evaporation recovered by the exhaust gas economizer (hereinafter referred to as electric power equivalent value) is Excess steam that exceeds the electricity demand is exchanged with seawater in a condenser, and the heat energy is wasted in the seawater. Furthermore, the energy loss for sucking in and discharging seawater for heat exchange increases.

(2) If the average onboard power exceeds the amount of evaporation from the exhaust gas economizer, the exhaust gas economizer cannot supply the onboard power, so an exhaust gas turbo generator is often not installed. Heat energy is wasted without being recovered.

(3) Furthermore, in an exhaust gas turbo power generation plant installed in such a way that average power and evaporation are balanced, when the maximum power demand onboard occurs, for example, before starting a large electric motor that exceeds the generator capacity, the For example, predicting the amount of electricity after starting the engine, starting one or two auxiliary diesel generators according to this predicted amount of electricity, and starting the same motor after running it in parallel with the exhaust gas turbo generator. A control device with predictive functionality is required.

In addition, depending on the load power amount, the number of diesel generators is controlled, resulting in extremely low load operation of the diesel generator, which can lead to undesirable results such as cylinder dirt, and the motor cannot be started after parallel operation of the generator. If the electric power forecast after the motor starts is not appropriate due to time delays such as power generation, there is a risk of overloading the generator. It has the disadvantage that it cannot be adapted to

The present invention was proposed in view of the above circumstances, and is capable of completely recovering the thermal energy of the exhaust gas of the main engine, constantly responding to the amount of power generated in response to changes in the onboard load power, and keeping the system frequency constant. The object of the present invention is to provide a marine power generation plant that controls the drum pressure of an exhaust gas economizer to a specified value.

A marine power generation plant according to the present invention includes an exhaust gas turbo generator connected to an exhaust gas economizer,
Operated in parallel with the above exhaust gas turbo generator, and
A main engine drive generator that can freely control the transfer of power to and from the main engine, a drum pressure detector that detects the pressure of the steam drum of the exhaust gas economizer, and a grid frequency detector that detects the frequency of the main bus; an exhaust gas turbo generator control device that controls the rotation speed of the exhaust gas turbo generator to keep the drum pressure at a specified value; and an output (including electric power output) of the main engine drive generator to keep the system frequency at the specified value. ) and a main engine drive generator control device.

An embodiment of the present invention will be explained with reference to the drawings.
Figure 1 is its system diagram, Figure 2 is a block diagram showing the control system in Figure 1, Figure 3 is an explanatory diagram showing the relationship between the exhaust gas economizer and exhaust gas turbo generator in Figure 1, and Figure 4. is an explanatory diagram showing the relationship between the main engine and the main engine drive generator in FIG. 1, FIG. 5 is a diagram showing the relationship between the prime mover load and the power generation frequency in FIG. 1, and FIG. FIG. 2 is a diagram showing the amount of steam generated and fluctuations in power of the main engine drive generator.

First, in FIG. 1, 1 is a propeller driven by the shaft of a main engine drive generator 2 directly connected to the main engine 3, 5 is an exhaust gas economizer attached to a smoke tube 4 that guides exhaust gas from the main engine 3, a water drum 6, It consists of a steam drum 7 and a heating coil 19. 8 is an exhaust gas steam turbine driven by steam from the steam drum 7; 9 is an exhaust gas turbo generator directly connected to the exhaust gas steam turbine 8; 10 is a turbine governor valve; 11 is a steam dump valve; 12 is the pressure of the steam drum 7. 13 is an exhaust gas turbo generator generated power detector that detects the output of the exhaust gas turbo generator 9; 14 is a main engine drive generator generated power detector that detects the output of the main engine drive generator 2; 15 is a system frequency detector, 16 is an inboard load, 17 is a power plant controller, 18 is a main engine drive generator frequency controller, 19 is a heating coil, 20 is a main bus, and 21 is a capacitor.

Next, in FIG. 2, 22 is a drum pressure setting device for setting the pressure of the steam drum 7, 23 is a subtracter, 24 is a function generator, 25 is a proportional-integral amplifier, 27 is a subtracter, and 28 is a Proportional amplifier, 29 is a system frequency setter, 31 is a subtracter, 32 is a proportional integral amplifier, 33 is a subtracter, 35 is a proportional amplifier, 3
7 is a subtracter, 38 is a speed governor for the exhaust gas steam turbine, 40 is a subtracter, 41 is a main engine drive generator frequency controller, and Aa is a drum pressure measurement value,
As is drum pressure setting value, Ae is drum pressure deviation value, EBa is exhaust gas economizer evaporation measurement value,
ETa is the measured power generated by the exhaust gas turbo generator,
ETe is the exhaust gas turbo generator power deviation value, Fs
is the grid frequency setting value, Fa is the grid frequency measurement value,
Fe is the grid frequency deviation value, Ea is the grid power measurement value,
ESa is the measured power generated by the main engine drive generator, ESe is the grid power deviation value, PSs is the main engine drive generator frequency setting value, PSe is the main engine drive generator frequency deviation value, PSa is the main engine drive generator frequency measurement value, and NTs is the main engine drive generator frequency measurement value. The exhaust gas turbo generator rotation speed setting value, NTe is the exhaust gas turbo generator rotation speed deviation value, and NTa is the exhaust gas turbo generator rotation speed measurement value.

In such a plant, the drum pressure measurement value Aa detected by the drum pressure detector 12 is transmitted to a function generator 24 and a subtractor 27 and is subtracted from the drum pressure set value As set by the drum pressure setter 22. , drum pressure deviation value Ae=
Obtain As−Aa.

The drum pressure deviation value Ae is determined by the proportional-integral amplifier 25.
is amplified to become the exhaust gas economizer evaporation measurement value EBa, and EBa is transmitted as it is to the subtractor 27 as the set value of the generated power of the exhaust gas turbo generator, and here the exhaust gas turbo generator generated power detector 1
Subtract the generated power measurement value ETa detected by 3,
Exhaust gas turbo generator power deviation value ETe=EBa−
Becomes ETa. ETa is transmitted to the proportional amplifier 28, and its output NTs is transmitted as the exhaust gas turbo generator rotation speed setting value to the subtractor 37, where the measured exhaust gas turbo generator rotation speed NTa is subtracted, and the output NTs is directly used as the exhaust gas steam turbine speed. Input to regulator 38,
The output signal of the same speed regulator is the exhaust gas steam turbine 8
and its output is the measured rotational speed of the same turbine.
Becomes NTa.

On the other hand, the grid frequency measurement value Fa detected by the grid frequency detector 15 is the grid frequency setter 29
is subtracted by the subtractor 31 from the set value Fs by
The deviation value Fe=Fs-Fa is input to the proportional-integral amplifier 32, and the output Ea becomes the measured value of the grid power.

Ea is subtracted by the subtractor 33 from the main engine drive generator generated power measurement value ESa detected by the main engine drive generator generated power detector 14 and the exhaust gas economizer evaporation measurement value EBa, resulting in the grid power deviation value ESe, which is proportionally amplified. 35 and becomes the main engine drive generator frequency set value PSs.

PSs is subtracted by the main engine drive generator frequency measurement value PSa by the subtractor 40, resulting in the main engine drive generator frequency deviation value PSe, which is input to the main engine drive generator frequency controller 41, and its output is the main engine drive generator frequency The measured value is PSa.

Furthermore, in order to maintain the drum pressure at a specified value even if the drum pressure measurement value Aa increases abnormally due to an abnormal occurrence of drum steam or an abnormal stop of the exhaust gas turbo generator, Aa is input to the function generator 24. If Aa is above the specified value, the output opens the steam dump valve 11 and releases the steam in the steam drum 7 to the condenser 21.

(1) In such a marine power plant, the following relationship holds true in the steady state of the power supply.

(a) EBa is proportional to the amount of steam generated by the exhaust gas economizer (electricity equivalent value).

As shown in FIG. 3, equation (1) holds true in the gas phase portion of the steam drum 7 of the exhaust gas economizer.

Vdγ/dt=Ga−ETa...(1) Where, V: Volume of steam drum gas phase, Ga: Evaporation amount (power equivalent value), ETa: Electricity generated by exhaust gas turbo generator, γ: Specific weight of steam, Here In a steady state, the temperature of the evaporated vapor and the pressure in the drum gas phase are constant, so dγ/dt=0, and therefore Ga=ETa. On the other hand, Aa, As, EBa, ETa, ETe,
Considering a control system consisting of NTs, NTe, and NTa, since it is in a steady state, ETe = EBa
−ETa=0 holds, therefore Ga=
ETa=EBa.

(b) Ea is proportional to load power.

The equation of motion (2) holds true for the main engine and main engine drive generator shown in FIG.

Tj/ωdω/dt=EEa−ESa...(2) However, EEa: Main engine power ESa: Measured power generated by main engine drive generator ω: Angular speed Tj: Acceleration constant Since it is in a steady state, there is no change in angular speed ω, Since dω/dt=0, EEa=ESa.

On the other hand, Fs, Fa, Ea, ESa, ESe, PSs,
PSe, PSa, EBa, ETa, ETe, NTs,
Considering a control system composed of NTe and NTa, it is in a steady state, so ESe = Ea - ESa - ETa = 0, and Ea = ESa + ETa.

(2) From the above relationship, in steady state,
The exhaust gas turbo generator generates electric power equal to the evaporation amount of the exhaust gas economizer (ETa = Ga), and the main engine drive generator generates electric power ESa = the load power minus the electric power equivalent to the evaporation amount of the exhaust gas economizer.
It is controlled to operate at Ea-ETa.

If the amount of evaporation from the exhaust gas economizer exceeds the load power, ESa=Ea-ETa<0, and the main engine drive generator receives electric power from the exhaust gas turbo generator as an electric motor to drive the main engine.

On the other hand, since dγ/dt=0, As=Aa, and since dω/dt=0, Fs=Fa, and the gas phase pressure and system frequency of the exhaust gas economizer are controlled to be equal to the set values.

(3) Furthermore, the operation in the case of load change and evaporation amount change will be explained with reference to FIG.

(a) In the figure, when the main engine drive generator is operating at ₁ point S and the turbo generator is operating at ₁ point T, the amount of evaporation from the exhaust gas economizer is ETa _1.
Suppose that it increases from ETa ₂ . This increase is due to an increase in the drum pressure measurement value Aa, a decrease in the drum pressure deviation value Ae, an increase in the exhaust gas economizer evaporation measurement value EBa, an increase in the exhaust gas turbo generator generated power deviation value ETe, and an increase in the turbo generator governor frequency set value NTs. As a result, the operating point of the turbo generator moves from T ₁ to T ₂ .

On the other hand, the load, that is, the grid power measurement value Ea, is constant, so if the main engine drive generator generated power measurement value ESa is initially constant, the grid power deviation value ESe is negative, and the main engine drive generator operating point is S ₁ Then, the process moves to _S2 , and at this point, Ea-EBa-ESa=ESe=0 and a steady state is reached.

The same applies when the amount of evaporation in the exhaust gas turbo generator decreases.

(b) When the system load becomes zero while the exhaust gas turbo generator is operating at ₁ point T and the main engine drive generator is at ₁ point S, the system frequency begins to rise to Fao, Fe decreases, and Ea decreases. Decrease. but,
Since EBa still exists at ETa ₁ , ESe starts to decrease with ESa constant initially, and eventually Ea = 0, ESa < 0, ESe = -ESa - EBa
=0. That is, the operating point of the main engine drive generator also becomes the _T1 point, the main engine drive generator receives the output of the exhaust gas turbo generator, and the main engine drive generator acts as an electric motor.

(c) If the grid load power suddenly increases while the exhaust gas turbo generator is operating at ₁ point T and the main engine drive generator is at ₁ point S, the frequency Fa of the grid becomes Fao−T ₁ point,
Fao−S starts to decrease along _one point, Fe increases,
Fa increases, initially ESe increases, ESa increases, and finally ESa = Ea − EBa,
The power generated by the main engine drive generator increases.

Figure 6 shows an example of the fluctuations in the above-mentioned onboard power, evaporation amount, and power generation amount of the main engine drive generator.
P ₁ represents the power generated by the main engine drive generator as an electric motor to drive the main engine, and P ₂ represents the power generated by the main engine drive generator as a generator.

According to such a marine power plant, the following effects can be achieved. In other words, (1) When the amount of evaporation from the exhaust gas economizer is equal to the onboard power demand, the hull power is supplied by the exhaust gas turbo generator, and the main engine drive generator is operated with no load, so that the main engine of the ship generates electricity. As much as possible, the exhaust heat energy can be recovered as electricity.

Furthermore, since there is no excess steam to be dumped, the amount of seawater used to cool the condenser is also reduced, thereby reducing the amount of power required for the pumps that circulate the seawater.

(2) When the amount of evaporation from the exhaust gas economizer exceeds the onboard power demand, the electrical energy recovered by the exhaust gas turbo generator is supplied to the main engine drive generator, which uses the generator as an electric motor to drive the main engine. can reduce fuel consumption.

(3) When the onboard demand power exceeds the generated power of the exhaust gas turbo generator, the main engine drive generator is instantly used as a supply source for the increased onboard demand power, and the onboard demand power exceeds the exhaust gas turbo generator power generation. By performing constant feedback control so that the main engine drive generator instantly becomes a recovery source for the reduced onboard power demand when the generated power is reduced, it is possible to adjust the increase or decrease of the onboard power demand without special operation monitoring means. Able to respond immediately.

(4) Even in marine power plants where exhaust gas energy is not recovered by an exhaust gas turbo generator because the amount of evaporation from the exhaust gas economizer is small compared to the onboard power, the present invention can be applied to generate an exhaust gas turbo generator, Parallel operation of the main engine drive generators increases the responsiveness to onboard power demand and makes it possible to recover exhaust gas energy.

In short, according to the present invention, an exhaust gas turbo generator connected to an exhaust gas economizer, and a main engine drive generator that is operated in parallel with the exhaust gas turbo generator and that can freely control the transfer of electric power between the main engine and the exhaust gas turbo generator. , a drum pressure detector that detects the pressure of the steam drum of the exhaust gas economizer, a system frequency detector that detects the frequency of the main bus, and a rotation speed of the exhaust gas turbo generator to maintain the drum pressure at a specified value. and a main engine drive generator control device that controls the output (including electric power output) of the main engine drive generator so as to maintain the system frequency at a specified value. INDUSTRIAL APPLICABILITY The present invention is industrially extremely useful because it provides a marine power generation plant that completely recovers the heat energy of the exhaust gas and constantly adapts the amount of power generated to fluctuations in onboard power demand.

[Brief explanation of drawings]

Figure 1 is a system diagram showing one embodiment of the present invention, Figure 2 is a system diagram showing an embodiment of the present invention.
The figure is a block diagram showing the control system in Figure 1, and Figure 3 shows the control system in Figure 1.
The figure is an explanatory diagram showing the relationship between the exhaust gas economizer and the exhaust gas turbo generator in Figure 1, Figure 4 is an explanatory diagram showing the relationship between the main engine and main engine drive generator in Figure 1, and Figure 5 is the diagram shown in Figure 1. FIG. 6 is a diagram showing the relationship between the prime mover load and the power generation frequency in FIG. 1...Propeller, 2...Main engine drive generator, 3...
... Main engine, 4 ... Smoke tube, 5 ... Exhaust gas economizer, 6 ... Water drum, 7 ... Steam drum, 8 ...
Exhaust gas steam turbine, 9... Exhaust gas turbo generator, 10... Turbine governor valve, 11... Steam dump valve, 12... Drum pressure detector, 13... Exhaust gas turbo generator generated power detector, 14... Main engine drive generator generated power detector, 15...System frequency detector, 16...Inboard load, 17...Power plant controller, 18...Main engine drive generator frequency controller,
19... Heating coil, 20... Main bus bar, 21...
Capacitor, 22...Drum pressure setting device, 23...
...Subtractor, 24...Function generator, 25...Proportional integral amplifier, 27...Subtractor, 28...Proportional amplifier, 29...System frequency setter, 31...Subtractor, 32 ...Proportional integral amplifier, 33...Subtractor, 35...Proportional amplifier, 37...Subtractor, 38
...Speed governor for exhaust gas steam turbine, 40...
Subtractor, 41...Main engine drive generator frequency controller,
Aa...Drum pressure measurement value, As...Drum pressure set value, Ae...Drum pressure deviation value, EBa...Exhaust gas economizer evaporation measurement value, ETa...Exhaust gas turbo generator generated power measurement value, ETe...Exhaust gas Turbo generator generated power deviation value, Fs... Grid frequency setting value, Fa... Grid frequency measurement value, Fe... Grid frequency deviation value, Ea... Grid power measurement value, ESa...
...Main engine drive generator generated power measurement value, ESe...System power deviation value, PSs...Main engine drive generator frequency setting value, PSe...Main engine drive generator frequency deviation value, PSa
...Main engine drive generator frequency measurement value, NTs...Exhaust gas turbo generator rotation speed setting value, NTe...Exhaust gas turbo generator rotation speed deviation value, NTa...Exhaust gas turbo generator rotation speed measurement value.

Claims (1)

[Claims] 1. An exhaust gas turbo generator connected to the exhaust gas economizer, a main engine drive generator that is operated in parallel with the exhaust gas turbo generator and can freely control the transfer of electric power to and from the main engine, and a steam generator of the exhaust gas economizer. A drum pressure detector that detects the pressure of the drum, a system frequency detector that detects the frequency of the main bus, and an exhaust gas turbo generator that controls the rotation speed of the exhaust gas turbo generator to maintain the drum pressure at a specified value. A marine power generation plant comprising: a control device; and a main engine drive generator control device that controls the output (including electric power output) of the main engine drive generator so as to maintain the system frequency at a specified value.