JPH02118309A - Fuel nozzle - Google Patents

Abstract

PURPOSE:To operate a gas turbine using the same burner and nozzle even if fuel composition is varied by providing a gas jet hole very near to an air jet hole of an air swirl vane and providing a jet hole in a gas nozzle. CONSTITUTION:Oil flows in a passage 35 from an oil fuel inlet and is jetted from an oil nozzle jet hole 36. Atomization air flows simultaneously therewith in a passage 38 and is jetted from an at an atomization air jet hole 40 in order to make atomizated oil mist. On the other hand, a coal gasified gas flows in a gas passage 41 in a gas nozzle and is jetted from a main jet hole 44 provided in the gas nozzle. In the case where the composition and heating value of the gas supplied varies and a flame is unstable, the flow jetted from the main jet hole 44 is varied, and part thereof is jetted from a sub-jet hole 43 provided in the neighborhood of an air jet hole of the outside of the gas nozzle. In other words, in order to optimize the jet speed at the main jet hole 44 largely influencing the stability of combustion, a part of a gas flow is supplied in the sub-jet hole 43. The flow ratio of the main and sub-jet holes is controlled by an orifice provided in the passage in the nozzles.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a gas turbine combustor that uses a fuel whose fuel composition changes depending on the type of coal, such as coal gasification gas, and particularly relates to a gas turbine combustor that uses a fuel whose fuel composition changes depending on the type of coal, such as coal gasification gas, and in particular, This invention relates to a fuel nozzle whose rate is controlled by an orifice.

[Conventional technology]

Conventional fuel nozzles have a structure in which the fuel injection port is divided into a main injection port and a sub injection port in order to stabilize combustion, and
The ratio of the main and sub flow rates is determined by a flow control valve. Further, this flow rate control valve is provided in the fuel flow path upstream from the jet port.

In general, in power plants that use coal gasification gas, the composition and calorific value of the coal gas supplied to the combustor vary greatly depending on the operating conditions of the gasifier and the type of coal used.
The flame in the combustor becomes unstable, causing a misfire.

In order to solve these problems, the fuel nozzle is designed to have the above-mentioned structure. The conventional nozzle and the nozzle of the present invention differ in the method of controlling the fuel supplied to the main ejection port and the sub-ejection port.

In the present invention, an orifice that can adjust the flow rate is provided in the flow path of the fuel nozzle. The flow rate ratio between the main jet port and the sub jet port is controlled by the orifice.

In addition, other conventional examples include the main fuel and the sub-fuel in different concentrations, as in Japanese Patent Laid-Open No. 194208/1983.

Some use the centrifugal force of the piping to control the ratio of main and sub flow rates.

This is a fuel nozzle for a pulverized coal burner, and the main fuel that is ejected from the inside of the nozzle is a pulverized coal flow, and the auxiliary fuel on the outside is a light pulverized coal flow that is mixed with air and then ejected. A mixed method is used.

Since the fuels are supplied tangentially to the nozzle body, they are subjected to centrifugal force in the pipe and then separated into main fuel and secondary fuel.

[Problem to be solved by the invention]

In JP-A-60-194208, no consideration was given to the reliability of controlling the flow rate ratio of the main fuel and the auxiliary fuel, and there was a problem in applying it to an actual gas turbine combustor.

An object of the present invention is to provide a fuel nozzle that allows a gas turbine to be operated using the same fuel nozzle and the same combustor even when the fuel composition changes.

The calorific value and fuel composition ratio of coal gasification gas vary depending on the type of coal, the type of gasifier, and the operating conditions of the gasifier. Therefore, when they are burned as fuel, the flame in the combustor becomes unstable as the calorific value and fuel composition change.

For this reason, it is desirable to avoid replacing the gas nozzle and combustor liner when the fuel composition ratio changes, and ideally the same fuel nozzle and the same combustor liner can be used.

[Means to solve the problem]

The above objective is achieved by optimizing the fuel flow rate through the jet orifice. Therefore, it is necessary to accurately differentiate the flow rate ratio of the fuel ejected from the main ejection port and the sub-ejection port.

Of the supplied fuel flow rate, the amount necessary to stabilize the flame, that is, divided into the main fuel and 2 auxiliary fuels that do not directly affect the stabilization of the flame6 Also, the amount that does not directly affect the stabilization of the large flame The fuel is ejected from the ejection port provided at a position that does not directly cause He to stabilize the flame.

The rate at which each fuel is ejected from the jet port varies depending on the composition of the fuel, and the rate is determined by the maximum required fuel flow rate.

The main and sub-flow ratio control is performed by installing an orifice that can adjust the flow rate in the fuel flow path from the main nozzle to the sub-nozzle, and the orifice can be easily replaced without removing the fuel nozzle. Structure.

By doing so, it is possible to stably burn fuels having different compositions.

[Operation] The calorific value and fuel composition of coal gasification gas vary depending on the type of coal, the type of gasifier, and the operating method of the gasifier. Therefore, it is desirable to avoid replacing fuel nozzles and combustor liners every time the gas composition changes.

That is, the development of a fuel nozzle with a wide operating range for gas turbines is an important technical issue.

The fuel nozzle of the present invention is divided into a main nozzle that directly affects flame stabilization, and a sub-nozzle that does not directly affect flame stabilization, and also has a branch that is divided into a main and a sub-nozzle in the middle of the fuel flow path inside the nozzle. The structure is such that a point is provided, and an orifice is provided there to adjust the flow rate.

By adjusting the area of the main jet nozzle to match the fuel with a higher calorific value among the target fuels, it is possible to easily handle fuels with a lower calorific value.

If you determine the optimal main nozzle area for fuel with a high calorific value, the total amount of fuel will increase for lower calorific values, so if the entire amount passes through the main nozzle, the ejection speed from the main nozzle will decrease. becomes faster. If this jetting speed is too high, a part of the total amount of fuel is branched off as auxiliary fuel, and the jetting speed from the main jetting port is set to an optimum value.

In this case, the main and sub flow rates are controlled by orifices.

With this configuration, a stable flame can be obtained using the same fuel nozzle regardless of the fuel composition.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Fifth
The figure is a system diagram of a coal gasification power plant.

The gas turbine 31 and the air compressor 14 are directly connected by a shaft 18, and the air pressurized by the compressor 14 is further pressurized by a booster 16 and supplied to the gasifier 5. Gasifier 58 uses coal 1. or.

2.3 is supplied, which is gasified and used as fuel.

Therefore, it is necessary to operate the gas turbine 31 with a fuel other than coal gasification gas before operating the gasifier 5. This plant does that with oil.

In addition, oil is not only used when starting up the gas turbine, but also when a problem occurs in the gasifier 5, desulfurization 6, dust removal device 7, etc. and coal gasification gas is not supplied to the combustor 26. use.

Next, the operation of the present invention will be explained.

Air compressor 1 is powered by external power such as a diesel engine.
4 is driven, and the turbine also rotates accordingly. When the rotational speed of the turbine 31 gradually increases and the speed of the turbine and compressor is increased to about 20% of the no-load rated rotational speed, the intake air is pressurized and supplied to the combustor as combustion air.

Then, the oil 12 is supplied to the combustor 26, starts ignition and combustion, and enters self-sustaining operation.

After that, the gas turbine/compressor gradually increases its speed and compressor 1
Air is discharged from 4, and a portion of the air is supplied to gasifier 5.

Meanwhile, the gasifier is supplied with coal and begins producing gas.

The gas gasified in the gasifier 5 is led to a desulfurizer 6 to remove sulfur contained in the gas. The desulfurized gas here is led to a dust removal bag [7] in order to remove solids contained in the gas, and is supplied to the combustor as purified coal gas 10.

When coal gasification gas is supplied to the combustor, it becomes possible to switch from oil-fired to coal-gas fired.

By switching to coal gas firing and increasing the rotational speed of the turbine 31, the driving force is utilized to cause the generator 32 to generate electricity.

Next, an embodiment of the fuel nozzle will be briefly described.

FIG. 1 is a sectional view of the fuel nozzle. The fuel nozzle consists of an oil system, a coal gas system, and an air system. An oil nozzle for performing oil-fired combustion is provided at the center of the fuel nozzle, and an atomizing air line 38 for spraying oil in the form of mist is provided on the outside thereof.

On the other hand, the coal-gas fired fuel nozzle has a gas nozzle 46 inside the fuel nozzle, in which a main ejection port 44 is provided. Further, an air jet port 45 is provided in a part of the outer swirler, and a sub-air jet port 43 is provided very close to the air jet port 45.

FIG. 2 is a cross section taken along the line ■-■ in FIG. Oil passes through the flow path 35 from the oil fuel inlet and is injected from the oil nozzle spout 36. At the same time, atomizing air is ejected from the atomizing air outlet 40 through the flow path 38 to atomize the injected oil. When the atomized air passes through the near ring 39, a swirling force is applied to the atomized air, and the atomized air collides with the oil at the tip of the nozzle. As a result, the atomized air spreads in a conical shape in front of the nozzle, making it easier to burn.

The spray air is pressurized by a separate atomizing air compressor and supplied to the nozzle.

On the other hand, the coal gasification gas passes through a gas flow path 41 within the fuel nozzle and is injected from a main jet port 44 provided in the gas nozzle.

If the composition or calorific value of the gas supplied here changes and the flame becomes unstable, you can change the flow rate ejected from the main nozzle and place a part of it near the air nozzle outside the gas nozzle. It is ejected from a certain sub-spout.

That is, in order to optimize the ejection speed of the main ejection port, which has a large effect on combustion stability, a part of the gas flow rate is supplied to the sub-ejection port.

The ratio of the main and sub flow rates is controlled by an orifice provided in the flow path within the nozzle.

FIG. 3 is a diagram showing an orifice provided in the fuel flow path within the nozzle. The gas nozzle has a main ejection port 44.

An auxiliary fuel flow path 42 that supplies gas to the auxiliary ejection port 43 is provided. An orifice 48 is provided between the auxiliary fuel passage 42 and the auxiliary nozzle 43 to control the flow rate ratio supplied to the main nozzle and the auxiliary nozzle. 6 After the coal gasification gas passes through the fuel passage 41 .

It is swirled and spouted from the main spout 44. At this time, if the flow rate of the fuel jetted out from the main jetting port 44 is too fast, a part of it is jetted out from the sub jetting port to optimize the jetting flow speed of the fuel.

This is because the orifice 48 has a removable structure.

By changing the diameter, the main and sub flow rate ratios can be separated with high accuracy.

FIG. 5 shows the ejection port of the fuel nozzle from the front. The oil fuel spout 36 is located in the center.

Atomizing air outlets 40 are provided around the periphery.

The main jetting port 44 for coal gas, which directly affects the stability of the flame, is provided at a position required to stabilize the flame slightly away from the center.

On the other hand, the auxiliary ejection port 43, which does not directly affect the stability of the flame, is provided at a position that does not affect the stability of the flame as much as possible.

According to the embodiment, when gas fuels having different compositions are used, the nozzle can be used as a common nozzle by simply replacing the orifice, if necessary.

〔Effect of the invention〕

According to the present invention, even if the calorific value and fuel composition ratio change depending on the type of coal and the operating status of the gasifier, a stable flame can be obtained by dividing the fuel into main and secondary parts and setting the optimum ejection speed. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fuel nozzle according to an embodiment of the present invention, and FIG.
The figures are a cross-sectional view taken along the line nn in Fig. 1, Fig. 3 is a detailed view of the orifice attachment part in the fuel nozzle, Fig. 4 is a front view of the fuel nozzle, and Fig. 5 is a plant system diagram of the present invention. . 1-3... Coal, 5... Gasifier, 21... Fuel nozzle.

Claims (1)

[Scope of Claims] 1. In a fuel nozzle comprising a nozzle body with a gas flow path, a gas nozzle, an air swirl vane, and an oil nozzle, a gas nozzle is provided in close proximity to the air nozzle of the air swirl vane, A fuel nozzle characterized by having a gas nozzle also provided with a nozzle. 2. The fuel according to claim 1, wherein the gas nozzle is not provided with the air nozzle, and the fuel ejected from the nozzle provided in the gas nozzle is configured so that the air does not directly collide with the fuel. nozzle. 3. Part of the flow path of the fuel ejected from the gas nozzle provided in the air swirling vane passes through the gas nozzle, and part of the fuel flow path to the nozzle provided in the gas nozzle is branched. The fuel nozzle according to claim 1, characterized in that the fuel nozzle has a structure in which the flow rate to each nozzle port is appropriately sealed. 4. Controlling the flow rate of fuel ejected from the gas nozzles either in the middle of the flow path up to the gas nozzle provided in the air swirling vane or in the middle of the flow path up to the gas nozzle provided in the gas nozzle. 2. The fuel nozzle according to claim 1, further comprising an orifice. 5. The orifice for controlling the fuel flow rate is made detachable, and the ratio of the jetting flow rate from the gas nozzle provided in the air swirling vane and the jetting flow rate from the nozzle provided in the gas nozzle can be changed depending on the diameter of the orifice. 5. The fuel nozzle according to claim 4, characterized in that: 6. The ratio of the amount of ejection from the gas nozzle provided on the air swirl vane to the amount of ejection from the gas nozzle provided on the gas nozzle is such that the lower the calorie gas, the higher the flow rate from the gas nozzle provided on the air swirl vane. The fuel nozzle according to claim 5, characterized in that the flow rate can be adjusted so that the ratio increases.