JPS6081408A - Load controller in compound-cycle power plant system - Google Patents

Abstract

PURPOSE:To execute the stable load control even if a vaporizer is put into trouble, by adding, into a load control system, a fuel-pressure control system for controlling the fuel pressure to a certain pressure set according to the atmospheric temperature. CONSTITUTION:The aimed load value (i) instructed to the variation-rate setting device 50 on each shaft is prepared in a load control system 67. In a fuel-pressure control system 66, the deviation value between the fuel pressure 14a at an LNG station and the fuel-pressure set value 61a determined according to the atmospheric temperature 66 is integration-calculated/proportionally, and the result value Ta is added into an adder 65 in the load control system 67. Therefore, even if a vaporizer in an LNG station is put into trouble, a certain pressure of boil-off gas can be obtained, and the operation of a power plant can be continued by effectively utilizing the boil-off gas.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a combined cycle centrifugal plant in which a gas turbine, a magnet generator, and a steam turbine are arranged on one axis. The load control table for plant systems is related to ζ2.

[Technical background of Kogu and its problems]

The fuel for combined cycle power plants is often liquefied natural gas (hereinafter abbreviated as LNG).

The system of the LNG terminal is explained in Figure 1 (see Figure 2). LNG transported by ship etc. is stored in one NG tank, and the LNG is pulled out with pumps 2.3a and 3b and vaporized. On the other hand, pour the seawater 7 pumped up by the seawater pump 6 into the respective vaporizers 4 and 5. The gas is regasified. This gas is sent to the magnetizing PJf through the twister d9 and used as fuel for boilers or turbine turbines.

Ma/ko LNG tank 1 (2) The LNG that is marked with
1. It is warmed up (-162'C), but the temperature outside the tank is 0'C-A0 (2.
If the difference in L is large, the gas will be gasified. This gas is called boil-off gas (hereinafter abbreviated as BOG).

Since this BOG fills the tank 1, a compressor is used to extract it, regasify it, and supply it to the fuel pipe 9. The fuel pressure 14 of this fuel pipe 9 is
It is controlled by adjusting needles 12 and 13 to maintain a constant pressure.

In a single-shaft combined cycle centrifugal plant, the gas from the fuel pipe 9 in Fig. 1 is controlled by a fuel control valve (2) and supplied to the combustor (2) of a gas turbine. The output of the gas turbine is determined by calculating the flow rate of fuel entering the combustor of the gas turbine by calculating the output of the gas turbine. is under control.

In addition, in an axial combined cycle magnet generator plant, the generator is directly connected to the gas turbine and the steam turbine, so the sum of the outputs of the gas turbine and the steam turbine is the output of the generator (2). The actual load detected from the gain and the load set value output from the load target value are calculated, and the load, that is, the generator output is controlled to be equal to the load setting (-).

As mentioned above (in the two-component cycle magnet generation plant C2, load control is always carried out,
If the vaporization 64.5 at the NG terminal stops due to a malfunction, etc., the power plant will be forced to shut down due to the accident at the LNG terminal shown in Figure 1 because not enough gas will be sent to the power plant. In this case (second), boil-off gas from tank 1 was constantly generated and had to be released into the air.

[Purpose of the invention]

The object of the present invention is to use the boil-off gas from the fuel tank in the power plant to stabilize the load d, without releasing the boil-off gas from the fuel tank into the air in the event of a failure of the LNG terminal's vaporizer, etc.
There are two systems that provide load control devices for cycle mine plant systems.

[Summary of the invention]

The present invention (2) provides a load control device for a fatigue cycle magnetizing plant system (2) for an axial combined cycle magnetizing plant (2); boil-off gas (2) to control the fuel pressure as a function of atmospheric temperature (2) to maintain a constant pressure (2) to control the load inside the launcher at a constant (2)
It is characterized by having two configurations.

[Embodiments of the invention]

The present invention will be described below in Figure 2 and! ! The embodiment shown in Figure II3 (
Let me explain about two things. First, a single-shaft pumping cycle centrifugal plant to which the present invention is applied will be shown. In Fig. 1, the gas turbine 21° steam turbine and magnet generator 26 constituting the magnet generating plant are directly connected together with the air compressor/wrinkle (-) by the same shaft. The gas from the fuel pipe 9 of the LNG 4 is connected to the fuel control valve (2, therefore 1IilI).
The combustor 22 of the gas turbine 21 is controlled and supplied to the combustor 22 of the gas turbine 21. The exhaust gas from the gas turbine 21 passes through the exhaust heat recovery boiler U to generate steam. This steam is supplied to the steam turbine δ through a steam control valve, and the enthalpy of the steam (steam that rotates the turbine 6 and drives the generator 26 directly connected to the same shaft to generate force) The steam that has finished working in the turbine station becomes condensed water in the water pump 217.

The price setting signal 31a of the pricing cycle generator plant shown in FIG. Steam turbine 2!
5 and the rotational speed 2'la of the magnet generator are subtracted by the subtractor 32 (two people), and the deviation signal obtained as a result of the subtraction is subjected to proportional calculation using the operational amplifier performance gain 33, and then the servo amplifier 34
This is done by increasing or decreasing the addition of the fuel control valve once through the fuel control valve.
22 (There are two people.The fuel flow rate is controlled and the gas turbine 2
1 output is controlled. On the other hand, for steam turbine b,
Since the enthalpy of the exhaust gas from the gas turbine 2 (2) determines the enthalpy of steam from the waste heat recovery boiler rot (2), the steam control valve side is kept open at a certain level (2) the vacuum of the condenser 27 degree (two more unique (two blades are determined).

As a result, since the generator 26 is connected to the gas turbine 21 and the steam turbine 25, the difference between the outputs of the gas turbine 21 and the steam turbine 2 becomes the output of the generator 26. The load detected by the output droplet load detector 35, the load output from the load target 1st shift 36, and the ir setting 5'
If the deviation of the rL generator signal is calculated by the subtractor 37 and the speed setting device 31 is changed according to the output (2), the final result (2 is the deviation is 4, that is, the load is the sulfur generator load output 35 is the load) Setting 361: C2 is controlled to be equal.

Next (1st brother 3rd figure shows the uniaxial compound cycle generation plant.
Multiple axes from IIaj+ to A load control device is shown.

Fig. 3 (In Figure 2, each axis is indicated by the part surrounded by a dotted line, the subtractor 37° in the 2nd df2, the generator load detector 35
The speed setter 31 has an independent valley circuit, and the input side of the valley subtractor 37 for each axis (a two-change rate foot device is provided).

The load target value l commanded by the change-overlapping device BO+2 for each of these axes is created by the negative DF control system 67 (2) shown in the figure. Either the load target value 41 of the combined cycle magnet generation plant system or the station mode YZ load target value 42 given from the load setter in the magnet generating station is selected by the switch 43, and then the target 1 is selected. This signal 43a passes through the entire load change rate setting device 44 and becomes the load signal 44a, which is then sent to the main open side (
2, the signal Ta of the fuel pressure control system 66 which controls the fuel pressure detected by the fuel pipe 9 in FIG.
When the carburetors 4 and 5 of the LNG terminal shown in FIG.

The signal 65a of the addition 465 passes through the load lower limit limiter 45 and the load upper limit limiter 46 and becomes the load command value 4 as a starting point.
It becomes 6a. In addition, the negative 1;・j from the first axis to the nth axis is added and is increased by the n unit 47. The i flatness difference of is calculated by the subtractor 481-, and the load target value 1 for each axis is obtained from the proportional-integral calculator 49 (2) which inputs the deviation. The load target value l becomes the load command value 36 for each axis by being removed so that the rate of change is within the rate of change limit value set by the rate of change setting device force for each axis.

Deviation l between the load command value 36 of each axis and the grinding force output 35 of each axis
is calculated by the subtracter 37, and the set value of the speed setter 31 is increased or decreased in accordance with the deviation l(2).From then on, the output control I+1 of the combined cycle plant is performed by the sub-circuit shown in FIG.

Now, the fuel pressure sub□□□ system circle provided according to the present invention 42 is as follows:
The pressure detector 14 detects the fuel pressure 14a of the fuel pipe 9 of the LNG terminal shown in FIG. is input into the subtractor 62 to calculate the deviation 62a, this deviation 62a is subjected to proportional and integral calculations in the calculator 63, and the resulting value Ta is applied to the load 10I through the switch 464.
I 11Il system 67 7IIll leg 65 (-additional (two-pointed).

In the fuel pressure setting device 61-, a function of the atmospheric temperature (= fuel pressure setting 4i[61a] is determined. As shown in FIG.
+Y2 (t2.p2) It is determined by the linear equation (2). When the LNG base is normal, the switch 64 selects the no signal Tb side (2) and circuit (2) is grounded,
In the case of an abnormality at the G base (2), the signal value Ta is selected and the adder 65 of the load weight 11 system 67 (2 is connected. This adder 65 is set in the central command center or power plant 1 section of the load setter 41 or 42 that has been
44a and Ix from the fuel pressure control system 66.
J! Add the resulting value Ta.

Next, the operation of the load control device of a combined cycle magnetization plant according to the present invention (2) will be explained with reference to FIG.
2, the signal is switched to the no-signal Tb side. and load T
In the olJIiIII system 67, the switching device 43 switches between the negative pre-target value 41a and the magnetic field internal mode load a li! 42a
The target load value i for each axis is obtained through control calculations each time it passes through each circuit. This load target 1 shift i
is the load command value 3 of each axis by the change rate setting device 50 of each axis.
The setting value of the speed setting device 31 is increased or decreased according to the deviation l between the generator output 35 of each axis and the generator output 35 of each axis.

For one year thereafter, the output control of the combined cycle plant will be performed by the control circuit shown in FIG.

Next, if during normal operation of the plant, the vaporizers 4, 5, etc. at the LNG terminal shown in Figure 1 fail and fuel cannot be normally sent to location i, the fuel specific force control system The switch 64 of 66 switches to the signal Ta 4111. At that time, if the load setter 41 from the central power dispatch center is selected by the switch 43, the switch 64 switches to the signal Ta 4111. The load setting position 42a in this case is
A value determined anew in the case of an LNG terminal accident is set.

In addition, in the case of an LNG terminal accident, the signal 6 from the fuel pressure setting device 61, which is set by a function of atmospheric temperature (2)
The deviation 62a between 1a and the actual fuel pressure 14a (this fuel pressure 14a is the pressure of the boil-off gas itself) is calculated as follows: The load target value 65a as a series determined in this way passes through the load upper limit value 45 and the load lower limit 1ji46 and reaches the load target value I as a series.
T! It becomes 46a. The following il and ill terms are the same as those described in step 11, so they will be omitted.

In this way, if an accident occurs at an LNG terminal and all the vaporizers are stopped (2), only the boil-off gas is at atmospheric temperature (2), so a constant pressure determined by
The load Tl1111111 is continued in order to effectively utilize the boil-off gas (1) to operate the generator 4 plant.

〔Effect of the invention〕

As mentioned above (in the second invention, a gas turbine.

The starting point is a single-shaft f-cycle plant system (2) in which multiple shafts are installed, including a single-shaft F anti-cycle centering plant with a model and a steam turbine. The load iI+lJ# system (
2. A fuel pressure control system has been added to control the fuel pressure by boil-off gas ζ1 to a constant pressure determined by the atmospheric temperature (2) when the vaporizer at the LNG base that supplies fuel to the front gas turbine is stopped. Therefore, even if the LNG terminal's vaporizer malfunctions, the boil-off gas from the LNG tank will not be released into nitrogen, but rather this gas will be used at the magnetic station to operate at a constant 1 tilJ s/u. By continuing, it becomes a Noh performance.

[Brief explanation of the drawing]

Figure 1 is a system diagram showing the gas distribution/a relationship at the LNG terminal, Figure 2 is a schematic configuration diagram showing a single-shaft combined cycle @tun plant, and Figure 3 is a system diagram showing the relationship between gas distribution and a at the LNG terminal. Fig. 4 is a system diagram showing an embodiment of the shell #1 control device of the magnetic gland system, and is a characteristic diagram showing a function of the boil-off gas pressure setting value depending on the atmospheric temperature (2). 1... LNG tank 4, 5 ... Carburetor 9 ... Fuel internal tube 21 ... Gas turbine 22 ... Combustor O ... Total air compressor 24 ... Exhaust heat recovery boiler δ ... Steam turbine 31 ...
...Speed setter 33...Adjustment rate gain 34...Servo amplification 435...Power generation load detector 36...Load target section 1 41.42...Load target (Direct-13...
Switcher 44... Load change rate setting device 45... Load lower limit limiter 46... Load upper limit limiter 49... Ratio,
Compensation calculation unit... Rate of change setter 61... Fuel pressure control system 63... Calculation unit 64... Switch 65...
adder

Claims (2)

[Claims] (1) A combined cycle plant system in which a gas turbine, a magnet wall, and a steam turbine are combined. In response to the load setting value, the load in the power generation station is made to follow the A load setting value (2) The load tfIIJ @ system and when the vaporizer at the LNG terminal that supplies fuel to the gas turbine is stopped (2)
The fuel pressure control system is equipped with a fuel pressure control system that determines the fuel pressure as a function of atmospheric temperature (=therefore determining the set value of the fuel pressure). The deviation between the fuel pressure set value, which is a function of atmospheric temperature (2), and the actual fuel pressure is calculated, and this is calculated as a function of the set fuel pressure (2), which is used as a load control system (
A load control device for a combined cycle to one plant system, characterized by having two configurations. (2) The fuel pressure control system is a function of atmospheric temperature (2) The deviation between the fuel pressure setter that determines the fuel pressure setting value and the fuel pressure detected by this fuel pressure setting value and the fuel piping of the LNG base. A calculator that calculates $, a calculator that calculates the deviation (proportionality and integral for two), and a calculator that calculates the result of this calculation into LNG.
Load control of a combined cycle generation plant system according to claim 1, characterized in that it is configured with two load jtllJ f'J system (two addition (two selection) switching devices) of the base. Device.