JPS60104728A - Purging for fuel oil in gas turbine - Google Patents

Abstract

PURPOSE:To prevent the sharp rise of combustion temperature by gradually purging fuel oil by gradually increasing the amount of purging air when the fuel oil in a fuel oil line is purged by air in the case when fuel gas is used in substitution for fuel oil. CONSTITUTION:When a gas turbine is driven by feeding fuel gas 26 in substitution for fuel oil 1 into a fuel injector 8, a solenoid valve 19 is excited by a control signal 25, after switching of fuel from oil to gas is performed, and a purge valve 22 is opened by the compressed air 11. After flow rate is controlled by allowing the purging air 20 to flow into a bypass 47 and a cushion tank 49 having orifices 48 and 51 on the upstream and downstream sides, said purging air is introduced into each fuel injector 8 through a manifold 23, and the residual oil is gradually purged. After the delay for a prescribed time on a timer 52, a solenoid valve 18 is excited to open a purge valve 50, and the amount of purging air is increased, and the residual oil is completely purged, and the top edge part of a fuel injection valve 31 is cooled.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is configured to enable switching operation between fuel oil and fuel gas (including mixed use of fuel oil and fuel gas).
The present invention relates to a method for purging fuel oil in a fuel oil line with purge air when the use of fuel oil is stopped and the operation is switched to fuel gas operation in Hygas turbine equipment.

[Background of the invention]

Fig. 1 is a system diagram showing the fuel and purge system of a cast turbine having a multi-cylinder combustor capable of dual fuel combustion using fuel oil and fuel gas, and Fig. 2 shows the fuel injection system for dual fuel combustion and the purge system. FIG. 3 is a detailed diagram showing a combination with a combustor. (See Figure 1) In the case of fuel oil firing, the fuel oil 1 passes through a fuel cutoff valve 2, is pressurized by a fuel pump 3, is controlled in flow rate by a fuel flow rate adjustment valve 4, passes through a fuel oil filter 5, and is sent to a fuel distributor. After being equally distributed among the fuel oil 6, the fuel oil is led to each fuel injection device 8 through a check valve 7. On the other hand, compressed electricity 11 extracted from a turbine compressor (not shown) is adjusted to a constant temperature by a spray air compressor 13.
4 is compressed and guided as fuel atomizing air 12 from an atomizing air manifold 15 to each fuel injection device 8 .

(See Fig. 2) The fuel oil 1 introduced into the fuel injection device 8 is guided through the entire fuel oil passage 32 inside the fuel injection device to the fuel injection valve 31, and then through the entire atomizing air passage 34. The fuel is atomized by the atomized fuel air and sprayed into the combustor inner cylinder 10 through the fuel injection port 35, where it is combusted.

When switching the fuel from fuel oil to fuel gas, the fuel switching operation opens the gas cutoff valve 27 shown in FIG. The fuel gas is guided to the fuel injection device @ 8 and passes through the fuel gas passage 33 shown in FIG.
Injected into the combustor inner cylinder 10 from δ. On the other hand, the flow rate of the fuel oil 1 is slightly reduced by the regulating valve 4, and the fuel cutoff valve 2 is closed after the fuel gas operation is completely switched to the fuel gas operation. At the same time, the solenoid valve (A) 18 is energized by the solenoid valve control signal 25, and the compressed air 11 opens the atomizing air bypass valve 17, so that the fuel atomizing air 12 is bypassed to the atomizing nitrogen bypass line 16. In addition, the solenoid valve (B) 19 is also energized, the purge valve 22 is opened, and the purge air 2o is released.
The purge manifold 23 passes the purge check valve 24 to each fuel injection device 8, and the fuel oil flowing into the fuel oil passage 32 and fuel injection valve 31 shown in FIG. This prevents clogging of the fuel injection valve 31 and fuel oil passage 32 due to carbonization of oil, and cools the tip of the fuel injection valve 31.

FIG. 3 shows changes over time during fuel switching, and changes in the amount of heat 41 due to fuel oil entering the cast turbine, the amount of heat 42 due to fuel gas, the gas turbine load 45, and the amount of purge nitrogen 43. It shows. After the fuel switching start time t1, while maintaining the amount of heat entering the turbine constant, the amount of fuel oil is decreased and the amount of fuel gas is increased, and the amount of fuel gas 1 is increased.
Fuel switching ends at time t2 when it reaches 00%. Immediately after the fuel switching ends, the purge valve 22 is opened at time 13 to start purging, and purge air flows, but the fuel oil remaining inside the fuel injection device 8 is instantly purged and combusted, so the combustion temperature rises rapidly. However, sudden load fluctuations 46 occur. Therefore, if the load at the time of fuel switching is large, there is a risk that the turbine trip will occur due to a sudden rise in exhaust temperature, which will cause damage and shortened lifespan of the high-temperature parts of the turbine. In order to avoid the above-mentioned danger, in the prior art, it has not been possible to switch from fuel oil to fuel gas in the high load range of the gas turbine.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a purge method that can prevent a sudden rise in combustion temperature at the start of purge and the accompanying load fluctuation, and to The aim is to prevent damage to parts and improve the reliability of gas turbine equipment.

[Summary of the invention]

In order to achieve the above-mentioned object, the method of the present invention, in gas turbine equipment that can selectively use fuel oil and fuel gas, connects the fuel oil line after switching from operation using fuel oil to operation using fuel gas. The amount of purge gas supplied to
The present invention is characterized in that the flow rate is gradually increased by the flow rate adjusting means, and the fuel remaining in the fuel oil line is gradually purged, thereby preventing a sudden rise in combustion temperature at the start of purging.

[Embodiments of the invention]

FIG. 4 shows a trellis of a fuel and purge system diagram constructed in order to carry out the method of the present invention, and this figure corresponds to part A surrounded by a chain line in FIG. 1 (prior device).

As shown in Fig. 4, a purge bypass line consisting of a purge tank (A) 50, a cushion tank 49, and orifices (A) 481, 4 ref. Furthermore, a timer 52 is connected to the solenoid valve control signal 25 line to the solenoid valve (A) 18.
It is installed.

Each of the above-mentioned components is operated as if they were not provided by a control device (not shown). When performing all purge operations according to the method of the present invention using this device, after switching the fuel from oil to gas, the solenoid valve control signal 25 is used to control the solenoid valve (B
) 19 is energized and the purge valve 22 opens, the purge air 2
0 is connected to the purge bypass line 47, orifice (A) 48, cushion tongue 49, orifice (B).
) 51 and is guided from the purge manifold 23 to each fuel injection device a8 to gradually purge the remaining fuel oil. After purging residual fuel oil, the solenoid valve control signal delayed by timer 52 causes stains (A).
18 is energized, purge valve (A) 5 (1) opens, increases the amount of purge air, completely purges the residual fuel oil, and cools the tip of the fuel injection valve 31.

FIG. 5 shows the change over time at the time of fuel switching in the above embodiment, and since the purge air amount change 56 after the purge start time t3 is small, the change in the residual fuel oil purge flow rate 55 is small. This prevents a sudden rise in combustion temperature, reducing turbine load &! ! ! 1(B)53 also becomes smaller. If the timer set time Tk/AwI is set to be longer than the time required to purge fuel oil, even if the purge valve (A) is opened at time t4 after time T and the purge air increases, the turbine load will fluctuate. does not occur. Therefore, smooth switching from fuel oil to fuel gas is possible over the entire load range.

When the purge operation was performed by the conventional method, the time required from zero to the steady-state value Q was on the order of 1/10 seconds when the purge air amount 43 rose at time 13 in FIG. In this embodiment (FIG. 5), by setting the illustrated time T to 4 seconds, the load fluctuation curve 53 increases 71.
11i has been reduced to virtually negligible S[.

According to experiments conducted by the present inventors, when the time T is varied, if this time is less than 1 second, there is a danger in the purge operation under high load conditions. By setting this time T' to 1 second or more, a significant improvement (reduction) in load fluctuation is observed.

In the present invention, gradually increasing the purge air tt' means increasing the time from zero flow rate to steady flow rate by 1.
It is meant to be more than a second. No upper limit is specified for this time due to technical constraints.

FIG. 6 is an example of a fuel and purge system diagram constructed for a different embodiment of the method of the present invention.

In this example 4', a flow control valve 59-t- is provided in the purge line to control the amount of purge air, and this figure corresponds to the 8 parts shown by chain lines in the conventional device (Figure 1) .

An example of implementing the method of the present invention using this device is to gradually open the purge air flow control valve 59 via the control valve drive device 60 in response to the flow control signal 61. That is, it is fully opened for more than one second from the fully open state. As a result, the amount of purge air is gradually increased, and the residual fuel oil is gradually purged (over 1 second), achieving the same effect as in the previous example.

FIG. 7 is a chart showing temporal changes in the purge air flow rate in order to explain a further different embodiment.

In this embodiment, from the purge start time t3 to the time t4 when the purge air flow rate reaches the steady value Q,
<Q <Q tk airflow 1fq is flown and increased stepwise. This also provides the same effect as the previous example. In the present invention, "gradually increasing" means that the purge air flow rate is kept on for more than 1 second from the start of purge until the purge air flow rate reaches a steady value. It may be curved or stepped.

[Effects of the Invention] As detailed above, the purging method of the present invention can switch from operation using fuel oil to operation using fuel gas in gas turbine equipment that selectively uses fuel oil and fuel gas. Immediately after, the purge air filter that supplies the fuel oil line,
By gradually increasing the flow rate using the flow rate adjustment means and gradually purging the fuel remaining in the fuel oil line to prevent a sudden rise in combustion temperature at the start of purge, a sudden rise in combustion temperature at the start of purge can be prevented. , and the accompanying load fluctuations can be prevented, and the switch from fuel oil to fuel gas can be safely performed even under high load conditions.It has excellent fc practical effects and improves the reliability of gas turbine equipment. There is a lot to contribute.

[Brief explanation of the drawing]

Figure 1 is a fuel and purge system diagram of a conventional gas turbine with a multi-tube combustor capable of dual fuel firing of fuel oil and fuel gas, and Figure 2 is a diagram of the fuel injection system and combustor for dual fuel firing. FIG. 3 is a diagram showing various changes over time during conventional fuel switching, FIG. 4 is a fuel and purge system diagram for explaining one embodiment of the present invention, and FIG. FIG. 6, which is a diagram showing each change over time during fuel switching in the above embodiment, shows an application example of the present invention, and shows a purge system in which the purge air region of the fuel oil line is controlled by a full flow rate control valve. FIG. 7 shows a further different embodiment f: a chart showing changes in the purge air flow rate for explanation. DESCRIPTION OF SYMBOLS 1...Fuel oil, 2...Fuel cutoff valve, 3...Fuel pump, 4...Fuel flow rate adjustment valve, 5...Fuel oil filter, 6...Fuel distributor, 7...・Fuel oil check valve, 8
...Fuel injection device, 9...Combustor outer cylinder, 10...
Combustor inner cylinder, 11... Compressed air, 12... Fuel atomizing air, 13... Atomizing air cooler, 14... Atomizing air compressor, 15... Atomizing air manifold, 16...
Atomizing air bypass line, 17... Atomizing air bypass valve, 18... Solenoid valve (A), 19... Solenoid valve (B)
, 20... Purge air, 21... Purge filter, 2.2... Purge valve, 23... Purge manifold, 24... Purge trace valve, 25... Electric #P control signal, 26...Fuel gas, 27...Gas cutoff valve, 28
...Gas flow control valve, 29...Gas manifold,
30...Cooling water, 31...Fuel injection valve, 32...
Fuel oil passage, 33... Fuel gas passage, 34... Spraying air passage, 35... Fuel injection port, 36... Waste injection port, 37... Compressor discharge air, 41... Fuel L in oil
/) Calorific value, 42... Calorific value due to fuel gas, 43...
Purge air amount, 44...Fuel oil, 45...J turbine load, 46...Rapid load fluctuation, 47.
... Purge bypass line, 48... Orifice (A
), 49... Cushion tank, 50... Purge valve (A), 51... Orifice (B), 52... Timer, 5.3... Load fluctuation (B), 55... Residual fuel oil purge distribution, 56...Kuichiji airflow filter, 57.
... When purge valve (A) is open, 59 ... Flow rate control valve, 60
... Control valve drive device, 61... Current control monument area. Agent Patent Attorney Masami Akimoto No. 1 Day 1V 2 and 29 Fig. 2 Kaya 50 Fig. 2 ↑ 1 No. 7 Continuation of page 1 [Phase] Inventor Takashi Miura Saiwai-cho, Hitachi City: Inventor Nobuyuki Mazai Hitachi City Kaisei Co., Ltd. Nemi-chome 1-1 Hitachi, Ltd. Hitachi Factory Chome 2-9-1 Hitachi Service Engineer Lido

Claims (1)

[Claims] 1. In gas turbine equipment that can selectively use fuel oil and fuel gas, immediately after switching from operation using fuel oil to operation using fuel gas, adjust the flow rate of the desired purge air amount supplied to the fuel oil line. A method for purging fuel oil in a gas turbine, the method comprising: gradually increasing the fuel oil percentage by increasing the percentage of fuel remaining in the fuel oil line, and gradually purging the fuel remaining in the fuel oil line to prevent a sudden increase in combustion temperature at the start of purge.