JPS6278406A - Gas turbine - Google Patents

Abstract

PURPOSE:To ensure the supply of gas fuel in an optimum amount at all times and the stable burning thereof by mounting a torque converter between a steam turbine and an increasing gear in a gas turbine for combined cycle power generation, and changing the speed of a gas fuel compressor. CONSTITUTION:A combined cycle power generation system is so made as to operate a generator 4 on a gas turbine 3 and a steam turbine 5. In this case, the drive shaft 6a of a gas fuel compressor 6 is coupled to an increasing gear 8 and a torque converter 41 is mounted between the increasing gear 8 and the steam turbine 5 as coaxially arranged with the gas turbine 3. Also, the oil feed line 42 of the torque converter 41 is fitted with an adjusting valve 43. And the amount of feed oil into the torque converter 41 is regulated with the adjusting valve 43 and a ratio of rotary speeds is adjusted between the input and output shafts 41a and 41b of the torque converter 41, thereby changing the speed of the gas fuel compressor 6 depending upon the speed or the load condition of the gas turbine 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas turbine, and more particularly to a gas turbine in which fuel is supplied optimally depending on the speed or load condition of the gas turbine.

[Technical background of the invention]

In recent years, combined cycle power generation has been attracting attention from the perspective of effective energy use, and this system has been adopted not only for commercial power generation but also for private power generation in the steel industry and the like.

Figure 17 shows a combined 1-Nicle power generation system used in the steel industry, etc., where 1 is an air compressor, 2 is a combustor, 3 is a gas turbine, 4 is a generator, 5 is a steam turbine, and 6 is a steam turbine. is a gas fuel compressor. Low-pressure, low-calorie gas 2 emitted from a blast furnace (not shown) as a gas source
After impurities in the gas are removed by a gas collector 7, the gas 1 is compressed by a gas fuel compressor 6 driven by a speed increaser 8 disposed coaxially with the gas turbine 3, and the gas fuel 11 is converted into gas fuel. The gas is supplied to the combustor 2 from a gas fuel supply system A equipped with a valve 9, and the air is compressed! It mixes with the compressed air 22 discharged from fi1 and burns. The high-temperature, high-pressure combustion gas generated in the combustor 2 operates the gas turbine 3, thereby driving the power generation III4. Further, a bypass system B is provided on the discharge side of the gas fuel compressor 6 to recirculate surplus gas fuel F'123, and this bypass system B is provided with a bypass system B that recirculates the surplus gas fuel F'123. A gas cooler 1o and a bypass valve 11 are provided to cool the fuel.

In addition, the high temperature and high pressure lJl gas discharged from the gas turbine 3 is transferred to the waste heat recovery boiler 12, and in this boiler 12, high pressure and low pressure drums (not shown) are used.
exchange heat with condensate inside. The steam generated in the high-pressure and low-pressure drums flows into the steam turbine 5 via the high-pressure steam control valve 13 and the low-pressure steam control valve 14.
It flows into the steam turbine 5 through the steam turbine 5, and operates the steam turbine 5. Further, the steam that has done work in the steam turbine 5 becomes condensate in a condenser 15, and this condensate is returned to the waste heat recovery boiler 12 by a feed water pump 16.

In such a combined cycle power generation, speed and load control are performed by controlling the flow rate of the gas fuel discharged from the gas fuel compressor 6 using the gas fuel valve 9 installed on the gas turbine 3 side. This was done by adjusting the

However, before starting the gas turbine 3, storing speed, etc.
Due to the low rotational speed of the gas turbine shaft, the gas fuel compressor 6
When the discharge pressure is low and sufficient gas fuel cannot be obtained, or when the supply of low-pressure, low-calorie gas 21 from the blast furnace is unstable, use the stand-up combustor 2 as an auxiliary fuel in addition to the above gas fuel.
The gas turbine 3
In other words, combined cycle power generation was being operated.

FIG. 8 shows the operating state of the gas turbine 3 used in the above-mentioned combined cycle power generation, and 31 is the gas turbine 3.
, 32 is the load of the gas turbine 3, 33 is the flow rate of the low-calorie gas fuel discharged from the gas fuel compressor 6, 3
4 is the flow m of low-calorie gas fuel flowing into the gas turbine 3
It shows.

The gas turbine 3 is started to operate by a starting device (not shown), and after a predetermined amount of time has elapsed since starting J, at point A, the gas turbine 3 is heated to warm up, and then at point 8, the rotation speed increases to 31. 17
■The engine starts and speeds up to the rated speed. gas turbine 3
After the rotational speed reaches the rated rotational speed, the load 32 is applied at the 0 point, and the load 32 is gradually increased. On the other hand, the gas fuel compression 1 m 6 , J: the gas fuel flow rate 3 discharged
3 and gas fuel flow rate 34 flowing into the gas turbine 13
is gradually increased as the gas turbine 3 starts up and speeds up, and the discharged gas flow rate 33 reaches the rated flow rate at point D when the inlet guide IXI (not shown) of the gas fuel compressor 6 is fully opened. Further, after the discharge gas flow ff133 reaches the rated flow rate, the exhaust gas from the gas turbine 3 starts operating the steam turbine 5, and as the steam turbine 5 operates, the load 32 of the gas turbine 3 increases to the rated load. With this increase in load 32, the gas flow 34 entering the gas turbine 3 is also increased to the rated flow m.

Further, the gas fuel compressor 6 that discharges the gas fuel flowing into the gas turbine 3 is driven by a separately installed starting device (not shown) until the gas turbine 3 reaches the rated rotation speed. After reaching it, it is connected to the gas turbine shaft.

[Problems with background technology]

Regarding the combined cycle power generation configured in this way, the gas fuel 11 discharged from the gas fuel v1 compressor 6 during the period from the startup of the gas turbine 3 to the time when the gas turbine 3 reaches the rated load.
The flow ff133 is larger than the gas combustion mixed flow mother 34 flowing into the combustor 2, as shown by the shaded area in FIG.
This surplus gas fuel 23 had to be returned to the gas supply source through a bypass system B provided on the discharge side of the gas fuel compressor 16.

However, since the gas fuel discharged from the gas fuel compressor 6 is compressed and has a high temperature and high pressure, it is cooled over time in the gas cooler 10 and then refluxed into the gas 21 discharged from the blast furnace. This delay in response in the gas cooler 10 makes it easy for the temperature of the low-calorie gas 21 flowing into the gas fuel compressor 6 to fluctuate, and furthermore, it is discharged from the gas fuel compressor Ilj, 6 to the combustor 2. When the temperature of the gas fuel flowing into the gas turbine 3 is varied and the temperature of the gas fuel Fl is greatly varied, there is a problem in that the speed or load of the gas turbine 3 cannot be sufficiently controlled.

In particular, when starting up the gas turbine 3, it is necessary to flow the surplus gas fuel F123 into the bypass system B while adjusting it with the bypass valve 11, and the opening and closing of the bypass valve 11 is controlled by the gas flowing into the gas fuel compressor 6. There is a problem in that the pressure of the gas turbine 21 tends to fluctuate, and the speed or negative pre-control of the gas turbine 3 cannot be sufficiently controlled, similar to the temperature fluctuation described above.

In addition, except when the gas turbine 3 is operating at the rated load, it is necessary to always bypass the surplus gas fuel 23 as shown in FIG. 8, and this surplus gas fuel 23 is bypassed by the discharge pressure of the gas fuel compressor 6. Since the excess gas fuel 23 flows through the system B, the driving force of the gas fuel compressor 6 is required to compensate for the flow of the surplus gas fuel 23, resulting in a problem that the overall efficiency of the combined cycle power generation decreases.

In addition, the low-pressure, low-calorie gas discharged from the blast furnace21
Since its components, pressure, flow rate, etc. tend to vary depending on the state of the blast furnace, there is a problem in that it is not possible to sufficiently control the speed or load of the gas turbine 3, and by extension, the speed or load of combined cycle power generation.

[Purpose of the invention]

Therefore, the purpose of the present invention is to solve the problems of the prior art described above, and to provide a gas turbine for combined cycle power generation in which R-suitable fuel is combusted in accordance with the speed or load condition in all operating ranges other than rated operation. This is to ensure that the water is supplied to the vessel.

[ll of invention! Essential]

In order to achieve the above object, the present invention arranges an air compressor, a gas turbine, a generator, a steam turbine, a speed increaser, and a gas fuel compressor coaxially, and the gas fuel sent from the gas generation source is The gas-fueled F3+ compressor driven by the speed increaser compresses the gas, supplies it to the combustor from the gas fuel supply system to operate the gas turbine, and uses the exhaust gas energy of this gas turbine to generate steam to operate the steam turbine. In a gas turbine for combined cycle power generation in which the generator is driven by the gas turbine and the steam turbine, a torque converter is installed between the steam turbine and the speed increaser, and the input shaft of the torque converter is connected to the steam turbine. It is connected to the rotating shaft of
The shaft is connected to a speed increaser, and by controlling the opening and closing of a UAI valve installed on the oil supply line of the torque converter, the oil supply to the torque converter is adjusted and the rotational speed ratio of the input shaft and output shaft is adjusted. The present invention is characterized in that the rotation speed of the gas fuel compressor is changed by changing the rotation speed of the gas fuel compressor, so that the optimum fuel is supplied depending on the speed or load condition of the gas turbine.

[Embodiments of the invention]

Embodiments of the gas turbine according to the present invention will be described below with reference to FIGS. 1 to 6. Note that the same reference numerals are used for the same parts as in the prior art, and the explanation thereof will be omitted.

In Fig. 1, the reference numeral 21 indicates the low pressure discharged from the blast furnace;
This gas 21 is compressed by a gas fuel compressor 6 and is supplied as gas fuel to the combustor 2 from a gas fuel supply system A equipped with a gas fuel valve 9, and compressed air 22
The gas turbine 3 is operated by mixing with the gas and combusting it. Further, the exhaust gas discharged from the gas turbine 3 uses its thermal energy to generate steam in the drum and operate the steam turbine 5. Then, the gas turbine 3 and the steam turbine 5
Generate electricity by driving! ! 14.

The drive shaft 6a of the gas fuel compressor 6 is connected to a speed increaser 8, and a torque converter 41 is installed between the speed increaser t, 18 and the steam turbine 5 coaxially arranged with the gas turbine 3. It is.

The torque converter 41 has an input shaft 41a connected to the rotating shaft of the steam turbine 5, and an output shaft 41a thereof.
b is connected to the speed increaser 8, and the torque converter 41 is provided with a direct connection device (not shown) such as a clutch that directly connects the input shaft 41a and the output shaft 41b. Further, a control valve (or solenoid valve) 43 is provided in the oil supply line 42 of the torque converter 41, and the amount of oil supplied into the torque converter 41 is adjusted by controlling the opening and closing of this control valve/I3. The rotation speed ratio between the input 4qb 41a of the Herc=1 inverter 41 and the output shaft -11b is adjusted. In addition, the above gas fuel 1'il V
A rotation speed detector 44 for measuring the rotation speed is installed at the end of the rotation shaft 6b of the crumpled squash 6.

FIG. 2 shows a control device for setting the opening degree of the control valve 43, in which 51 is a function generator, 52 is a valve position control circuit, and 5
3 is a high value priority circuit.

When a constant speed signal 61; J5 and a load setting signal 62 of the gas turbine 3 are inputted to the function generator 51, one of the signals 61 and 62 is output depending on the speed control or load control of the gas turbine 3. A speed setting signal 63 for the gas fuel compression 116 selected and corresponding to the selected speed setting signal 63 is output. The speed setting signal 63 output from this function generator 51 is a value obtained by calculating h1 in advance with respect to the signal 61.62, and when the speed of the gas turbine 3 is increasing, The calculated value of Ki, which is obtained by adding the bias divided flow G to the fuel hot stone necessary for rated operation, etc., is output as the speed setting signal 63, and when the gas turbine 3 is under load, the bias is applied to the fuel flow proportional to the load. The il E value to which the divided flow rate has been added is output as the speed setting signal 63. Here, the reason why the bias partial flow rate is added as described above is to provide a margin for the fuel flow m supplied to the gas turbine 3 and to always secure more gas fuel than necessary.

When the speed setting signal 63 is input to the valve position control circuit 52, the opening setting signal 64 calculated in advance is set to high Ms f15.
The opening setting signal 64 is outputted to the preceding circuit 53, and in this high value priority circuit 53 is compared with the minimum opening setting signal 65, and the opening setting signal 64 outputted to the control valve/13 becomes the minimum opening setting. Adjustment is made so that the signal does not fall below 65. Here, the opening setting signal 6/l is adjusted in order to prevent the 1-lux transmission from becoming unstable due to a decrease in the amount of oil supplied into the 1-lux converter 41 due to excessive throttling of the control valve 43. It is.

As described above, by controlling the amount of oil supplied into the 1-to-1 converter 41 with the control valve 43 and adjusting the ratio of the rotation speeds of the input shaft 41a and the output shaft 41b, the amount of oil supplied to the output shaft is increased through the speed increaser 8. 41b and j↑ The rotational speed of the gas fuel compressor 6 which is being depleted can be changed according to the speed method or load condition of the gas turbine 3. For this reason, gas-fueled Fl compression reform 6
The flow rate of the gas fuel discharged is changed, and only the necessary gas fuel according to the speed or load condition is obtained, and excess gas fuel is not discharged. Therefore, the conventional bypass system B is not required, and the speed or load of the gas turbine 3 can be stably controlled only by adjusting the gas fuel flow rate using the gas fuel valve 9.

3 to 6 show other embodiments of the control terminology of the control valve 43. Note that the same parts as in the above embodiment are given the same reference numerals, and their explanations will be omitted.

In FIG. 3, the rotation speed of the gas fuel compressor F36 is fed back to the controller 211, and 71 indicates an adder. The speed setting signal D63 output from the function generator 51 and the actual rotation speed 81 of the gas fuel compressor 6 measured by the rotation speed detector 44 are added by the adder 71, and the difference signal 82 is An opening degree setting signal 64 is output from the valve position control circuit 52. In this way, since the actual rotation speed 81 of the gas fuel compressor 6 is fed back, it is possible to perform the rotation speed index DI+ of the gas fuel compressor with higher accuracy.

Figure 4 shows the gas fuel r1 compression in the control device! ! The compressed air pressure 101 discharged from the air compressor 1a11 is calculated by the adder 91 and 92.
A calculated value obtained by adding bias pressure 102 such as fuel valve pressure loss and piping pressure loss to the total pressure and subtracting the discharge pressure 103 of the gas fuel compressor 6 from this total pressure is input to the valve position control circuit 93, and the opening setting signal is It is output as 104 to the high value priority circuit 97I. Here, the opening setting signal 104 is compared with the opening setting signal 64 based on the speed setting signal 63 output from the parameter generator 51, and the signal with the larger value is output to the control valve 43. In this way, the discharge pressure J103 of the gas fuel compressor 6 is smaller than the compressed air pressure 101J, and the opening setting signal 104 outputted to the high value priority circuit is the opening setting signal 6 outputted from the function generator 51. /1, the opening setting signal 104 is output with priority and acts to increase the discharge pressure 103, so that the gas fuel r1 compression 1j! The discharge pressure 103 of the combustor 16 is always higher than the total pressure of the compressed air pressure 10"l plus the bias pressure 102, which makes it possible to stably supply gas fuel to the combustor 2. It is possible to prevent the backflow of gas fuel and the accompanying blow-out of the combustor 2.

FIG. 5 shows an additional circuit that directly connects the torque converter 41 to the control device. When the load of the gas turbine 3 reaches the rated load and enters rated operation, the fuel flow rate becomes constant, so the gas fuel compressor 6 by the torque converter 41
Rotation speed control becomes unnecessary. Therefore, when the rated load is reached, the rated load signal 121 is input to the function generator 111, and the direct connection signal 122 is outputted to operate the direct connection product of the torque converter 41. Also, if the torque converter 41 is directly connected, there is no need to supply oil into the torque converter, so
The rated load signal 121 is input to another function generator 112, and a full open signal for stopping oil supply is outputted to the regulating valve 43 via the timer 113 and the low value priority circuit 114. The timer 113 allows the control valve i43 to be fully opened after the torque converter 41 has been directly connected.

The function generator 112 always outputs a fully open signal for the control valve 43 when the rated load signal 121 is not under human power, and this full open signal is output to the control valve 43 via the low value priority circuit 114. Therefore, the opening degree setting signal 64 from the function generator 51 is output to the control valve 43 except for the rated load.

In FIG. 6, the signal input to the function generator 51 is used as the opening degree setting signal 131 of the gas fuel valve 9.

Since the opening setting signal 131 is proportional to the fuel flow rate, the rotation speed of the gas fuel compressor 6 can also be controlled by this embodiment.

Furthermore, by combining the various control devices described above, a more reliable control valve/I3 control device can be provided, and the speed of the gas turbine 3 is stabilized by controlling the rotation of the gas fuel compressor 6 by the torque converter 41. load control. Further, the present invention can be applied to a combined cycle power generation system equipped with a conventional bypass system B, and gas fuel can be stably supplied.

〔Effect of the invention〕

As is clear from the above description, the present invention connects the input shaft of a torque converter to the rotating shaft of a steam turbine disposed coaxially with the gas turbine, and connects the output shaft of the torque converter to a speed increaser. By adjusting the oil supply to the converter and adjusting the rotation speed ratio of the input shaft and output shaft, the rotation speed of the gas fuel compressor driven by the speed increase mode is changed according to the speed or load condition of the gas turbine. The required gas fuel r1 according to the speed or load condition can be supplied and stable combustion can be performed.

[Brief explanation of drawings]

Fig. 7 is a block diagram showing a combined cycle power generation system including a gas turbine according to the present invention, and Figs. 7 is a block diagram showing conventional combined cycle power generation, and FIG. 8 is a diagram not showing the operating state of the gas turbine in conventional combined cycle power generation. 1...Air compressor, 2...! ! Burner, 3...gas turbine, 4...fil! , 5... Steam turbine, 6... Gas fuel r1 compressor, 8... Speed increaser, 9...
・Gas fuel valve, 10...Gas cooler, 11...Bypass valve, A...Gas fuel reserve system, B...Bypass system, 21...However, calorie gas, 22...Compression air,
23... Surplus gas fuel, 31... Gas turbine rotation speed, 32... Gas turbine load, 33... Gas fuel compressor discharge stream, 34... Incoming gas flow, 41...
Torque converter, 41a...input shaft, 41b...
Output shaft, 42... Oil supply line, 43... Control valve, 5
1... Function generator, 52... Valve position control circuit, 53
...High value priority circuit, 61...Speed setting signal, 62.
...Load setting signal, 63...Speed setting signal, 64...
- Opening degree setting signal, 65... Minimum opening degree setting signal. Figure 4 Figure 5

Claims (1)

[Claims] 1. An air compressor, a gas turbine, a generator, a steam turbine, a speed increaser, and a gas fuel compressor are arranged coaxially, and the gas fuel sent from the gas generation source is transmitted through the speed increaser. The gas fuel is compressed by a driven gas compressor and supplied to a combustor from a gas fuel supply system to operate a gas turbine, and the exhaust gas energy of this gas turbine is used to generate steam to operate a steam turbine. In a gas turbine for combined cycle power generation in which a steam turbine drives the generator, a torque converter is installed between the steam turbine and the speed increaser, and the input shaft of the torque converter is connected to the rotating shaft of the steam turbine. At the same time, the output shaft is connected to a speed increaser, and the amount of oil supplied to the torque converter is adjusted by controlling the opening and closing of a control valve provided on the oil supply line of the torque converter, and the output shaft is connected to the input shaft and output shaft. A gas turbine characterized in that the rotation speed of the gas fuel compressor is changed by changing the rotation speed ratio. 2. The gas turbine according to claim 1, wherein the torque converter is provided with a direct connection device that directly connects the input shaft and the output shaft. 3. The gas turbine according to claim 1, wherein the opening degree of the control valve is set by a speed setting signal and a load setting signal of the gas turbine.