JPH01267324A - Gas turbine combustor for low calorie gas - Google Patents

Abstract

PURPOSE:To ignite low calorie gas so easily by setting up a ceramic subcombustion chamber, provided with an auxiliary burner, at the inlet side of a main combustion chamber, while installing a main fuel injection nozzle and a combustion air injection nozzle in and around an outlet of the subcombustion chamber. CONSTITUTION:A ceramic subcombustion chamber 2 is set up at the inlet side of a main combustion chamber 1. Likewise a main fuel injection nozzle 6 and a combustion air injection nozzle 4 are set up in and around an outlet of this subcombustion chamber 2. Then, a low calorie gas header for low calorie gas or the main fuel is thus constituted. In addition, an auxiliary burner 5, spraying a mixture between high calorie gas or the auxiliary fuel and combustion air, is set up in an inner part of the subcombustion chamber 2. A high temperature flame formed in the inner part of the subcombustion chamber is whirled and sprayed to the side of the main combustion chamber 1. With this constitution, the high temperature flame is generated in the subcombustion chamber 2 where combustion air for cooling is no longer required, whereby combustion for the low calorie gas being sprayed out of the circumference is made so easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (-Field of Application of Togami) The present invention relates to a gas turbine combustor. More specifically, the present invention relates to a gas turbine combustor for low-calorie gas that uses low-calorie gas, such as coal gasified gas, as fuel.

(Conventional technology) Currently, the development of coal gasification or liquefaction technology has been proposed as a means of developing coal conversion and utilization technology, and is being promoted in various countries. As part of this development, we will develop a gas turbine for low-calorie gas that uses gas produced by coal gasification (hereinafter referred to as coal gasified gas or produced gas), especially low-calorie gas of less than 2000 kcal/Nm3, as fuel. The development of a combustor is required.

In other words, the conventional gas turbine combustor (compaster) is
It is a device that injects fuel into a stream of compressed air and burns it continuously, and has the following characteristics: ■ High pressure in the combustion chamber, ■ High air velocity in the combustion chamber, and ■ High combustion load rate. , natural gas (LNG) and propane gas (LPG)
, assumes the use of high-calorie fuel such as oil.

On the other hand, coal gasification gas supplied from an air-blown entrained bed coal gasification furnace, which is especially suitable for large-scale power generation, has a content of approximately 1000 kcal/N m3 containing components such as CO1H2, N2, CO2, and H20. It is a low-calorie gas, and most of its main component, CO1H2, is CO gas, which is difficult to burn. For this reason, it is difficult to ignite and lacks flame stability, making it undesirable as a fuel for gas turbines.

Furthermore, it contains 1000 to 2000 pI) NH3 as an impurity, which generates NOx during the combustion process. Furthermore, when high-load combustion is performed, the fuel gas flows at a speed higher than the flame propagation speed, making it increasingly difficult to ignite. In addition, when using low-calorie gas, the amount of fuel increases dramatically compared to conventional gases, so changing the amount of combustion, or in other words, changing the amount of fuel supplied, changes the flow pattern of the combustion gas. ) itself, which greatly affects the stability of the flame, and which is different from conventional gas turbines in which the flow is determined by the combustion air due to the use of high-calorie gas, which essentially has no effect on the combustibility of the fuel. There is a difference.

For this reason, when low-calorie gas such as coal gasified gas is used as fuel in a conventional general turbine combustor, ignition failure, misfire, and combustion instability may occur.

Therefore, a turbine combustion system for low-calorie coal gas has been proposed to eliminate the instability of combustion when using this low-calorie gas as fuel (Japanese Patent Laid-Open No. 62-182
No. 532), as shown in Figure 5, this invention aims to maintain stable combustion by capturing the combustion flame and input gas components when the combustion state becomes unstable and replenishing an appropriate amount of oxygen. It is something.

(Problems to be Solved by the Invention) However, this conventional turbine combustor attempts to stabilize the combustion state by directly supplying oxygen into the combustion chamber when the combustion state becomes unstable. Therefore, it is not possible to achieve fuel-rich combustion on the upstream side of the combustion chamber, that is, near the fuel injection nozzle, and the generation of NOx cannot be reduced.In fact, the generation of NOx increases due to the supply of oxygen. In addition, it is not effective against misfires caused by accidents such as water or other foreign matter getting into the fuel supply system, especially when using ceramic turbines for high-pressure, high-temperature combined cycle power generation. If it flows into the turbine side, there is a risk of damage to the ceramic stator blades due to thermal stress.
It is essential to reliably avoid misfires, and this is an important problem that cannot be ignored.

Therefore, a first object of the present invention is to provide a gas turbine combustor that can use low-calorie gas as fuel. A second object of the present invention is to provide a misfire-free gas turbine combustor for low-calorie gas. A third object of the present invention is to provide a gas turbine combustor that burns a low-calorie gas that is difficult to burn without generating NOx.

(Means for Solving the Problems) In order to achieve the above object, the gas turbine combustor for low-calorie gas of the present invention is provided with a ceramic sub-combustion chamber equipped with an auxiliary burner on the inlet side of the main combustion chamber, and a ceramic sub-combustion chamber equipped with an auxiliary burner. A main fuel injection nozzle and a combustion air injection nozzle are arranged around the outlet of the auxiliary combustion chamber.

In addition, the gas turbine combustor for low-calorie gas of the present invention is provided with a ceramic sub-combustion chamber equipped with an auxiliary burner on the inlet side of the main combustion chamber, and a main fuel injection nozzle for combustion around the outlet of the sub-combustion chamber. An air injection nozzle is arranged to burn high-calorie gas in the sub-combustion chamber.

Further, in the gas turbine combustor for low-calorie gas of the present invention, the main combustion chamber burns the low-calorie gas of 90% or more of the total generated heat, and the sub-combustion chamber burns 10% of the total generated heat.
It is characterized by burning less high-calorie gas.

In addition, the gas turbine combustor for low-calorie gas of the present invention is provided with a ceramic sub-combustion chamber equipped with an auxiliary burner on the inlet side of the main combustion chamber, and a main fuel injection nozzle for combustion around the outlet of the sub-combustion chamber. An air injection nozzle is arranged, and the high calorie gas is combusted in the sub-combustion chamber, and is swirled within the sub-combustion chamber to be injected into the main combustion chamber.

Further, in the gas turbine combustor for low-calorie gas of the present invention, the main combustion chamber burns the low-calorie gas of 90% or more of the total generated heat, and the sub-combustion chamber burns 10% of the total generated heat.
It is characterized by burning less high-calorie gas.

Further, in the gas turbine combustor for low-calorie gas of the present invention, the injection axis of the auxiliary burner in the auxiliary combustion chamber is inclined with respect to the central axis of the auxiliary combustion chamber, and the outlet portion of the auxiliary combustion chamber is opened to widen toward the end. It is characterized by

(Operation) Therefore, since air for cooling the sub-combustion chamber is not required, λ can be set to 0.8 to 1.0, and high-temperature combustion gas/flame that is stable as a spark source can be obtained.

The flame of this high-calorie gas serves as a spark and improves the ignitability of the low-calorie gas injected around it.

In addition, the flame of high-calorie gas that is injected into the main combustion chamber while swirling in the sub-combustion chamber spreads due to its momentum as soon as it enters the main combustion chamber, and does not destroy the recirculation flow system (flame holding mechanism) in the main combustion area. .

(Example) Hereinafter, the configuration of the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows an embodiment of the present invention in a central vertical cross-sectional view. This gas turbine combustor is equipped with a ceramic sub-combustion chamber 2 on the inlet side of a main combustion chamber 1, and around the outlet of the sub-combustion chamber 2. A main fuel injection nozzle 3 and a combustion air injection nozzle 4 are arranged in the auxiliary combustion chamber 2 to form a low-calorie gas header for the low-calorie gas which is the main fuel, and high-calorie gas which is the auxiliary fuel and combustion air are placed in the sub-combustion chamber 2. An auxiliary burner nozzle 5 is provided to inject the mixture with the auxiliary burner nozzle 5, and the high-temperature flame formed in the auxiliary combustion chamber 2 is swirled and injected toward the main combustion chamber 1 side.

The combustor usually has a double-tube structure consisting of a gauging 6 and a liner 7, with a combustion air passage 8 formed between the liner 7 and the gauging 6, and the inside of the liner 7 forming the main combustion chamber 1. has been done. There are secondary air holes 9 in the front half of the liner 7.
And if necessary, a large number of tertiary air holes 10 are arranged in the circumferential direction, and the combustion air supplied to the flow path 8 between the casing 6 and the liner 7 is used as secondary air and, if necessary, tertiary air, to the combustion chamber 1. Secondary combustion and cooling of the combustion gas is performed if necessary. Further, a secondary air supply duct 11 is connected to the casing 6 and is provided so as to introduce combustion air into the flow path 8 through a supply port 12 connected to a combustion compressed air supply source. Further, in the liner 7, a primary air supply duct 13 surrounding the combustion air injection nozzle 4 of the low calorie gas header is connected to a secondary air supply duct 11.
The primary air is injected from the combustion air injection nozzle 4 around the main fuel injection nozzle 3 through a supply port 14 connected to the combustion air compressed air supply source so as to pass through the main fuel injection nozzle 3. There is. In addition, combustion air injection nozzle 4
A swirler may be installed as necessary to swirl the injected air.

The auxiliary combustion chamber 2 is provided on the inlet side of the main combustion chamber 1, and is installed at the center inside the main fuel injection nozzle 3. The auxiliary combustion chamber 2 is constituted by a cylindrical container, usually a cylinder, made entirely of ceramic or covered with a ceramic lining. As the ceramic, it is preferable to use, for example, silicon carbide ceramics, silicon nitride ceramics, sialon, etc.
This auxiliary combustion chamber 2 is fixed to a support plate 25 attached to the primary air supply duct 13 by, for example, a holding metal fitting 24. This support plate 25 is burnt. In addition, an auxiliary burner 5 is provided in this auxiliary combustion chamber 2, and a gas having a higher calorie than the fuel gas supplied to the main combustion chamber 1, for example, L
It is installed to burn NG, LPG, etc. as fuel.

The high-calorie gas is mixed in advance with combustion air at a constant air ratio, and is provided so as to be injected into the sub-combustion chamber 2 in a swirling manner. Therefore, the combustion gas turns in the auxiliary combustion chamber 2 and is ejected to spread rapidly toward the main combustion chamber 1.For example, in the case of this embodiment, the fuel gas and the combustion air are mixed in advance in the burner, A burner with a structure that swirls and injects the mixed gas is used. Specifically, a burner tip is used in which the injection axis of the burner tip is swung approximately 45 degrees from the inside to the outside. In addition, since this auxiliary burner 5 forms a high-temperature flame regardless of the amount of combustion, it is provided with a structure that allows the amount of combustion air to change depending on the amount of fuel injection and automatically maintain a constant air ratio. There are 6
For example, in the case of the auxiliary burner 5 of this embodiment, an ejector consisting of a drum-shaped diaphragm f@17 and a partition plate 18 is installed between the fuel injection nozzle 15 and the igniter (ignition device 16) installed in the center of the interior. At the same time, the fuel injection nozzle 15 is provided with an air supply hole 19, and combustion air is sucked in by an ejector effect using the velocity energy of the auxiliary fuel gas to obtain a constant mixture ratio.The mixture ratio λ is is normally set at 0.8 to 1.0 in order to obtain the maximum flame temperature.The outlet of this sub-combustion chamber 2 is widened into a conical shape, so that when the flame ejects into the main combustion chamber 1, An introduction pipe 23 is installed around the air supply port 19 to facilitate intake of combustion air flowing through the primary air supply duct 13.

Further, a main fuel injection nozzle 3 is formed around this sub-combustion chamber 2 . In the case of this embodiment, the main fuel injection nozzle 3 is provided with a large number of injection ports on the circumference that are inclined from the outside to the inside and in the circumferential direction, as shown in FIG. It is provided so as to collide with the auxiliary flame to be injected. An annular header 20 is connected to the main fuel injection nozzle 3, and is provided so as to uniformly inject low-calorie gas supplied from a low-calorie gas supply source, such as a coal gasifier, from the entire circumference. The header 20 is connected to an annular ladder 22 in the primary air supply duct 11 via a connecting pipe 21, and is connected to a gasification furnace or the like.

The high-calorie gas supplied to the auxiliary combustion chamber 2 accounts for less than about 10% of the total heat generated at rated output, that is, the proportion of the high-calorie gas supplied to the sub-combustion chamber 2 in the total heat generated by combustion of the entire fuel including low-calorie gas is less than 10%. The low-calorie gas supply system and the high-calorie gas supply system, which are preferably suppressed to a certain amount, are controlled separately, and have two mutually independent fuel systems.

Although the above-mentioned embodiment is an example of a preferred embodiment, it is not limited thereto, and various modifications can be made without departing from the gist of the present invention.9For example, as shown in FIG. If the structure is such that an economizer 31 is formed in the sub-combustion chamber 2 to preheat the fuel gas, high-calorie gas will be used as fuel from the time of ignition until it reaches the rated combustion state, and the combustion state will be stable. It is also possible to save on fuel costs by switching to low-calorie gas.

With the above configuration, low calorie gas such as coal gasification gas can be stably combusted. First, 1 of the total amount of heat generated
Less than 0% high calorie gas such as LPG or LNG
is supplied to the sub-combustion chamber 2, and ignited by the igniter 16.Next, coal gasification gas containing 90% or more of the total generated heat is supplied to the main combustion chamber 1 side, and the high-temperature flame of the high-calorie gas is used as the ignition source to generate low-calorie gas. Ignites and burns gas. Combustion air is supplied from the supply port 14 at an air ratio such that low-calorie gas and high-calorie gas are subjected to fuel-rich combustion on the upstream side of the main combustion chamber.

However, since the combustion air supplied to the auxiliary burner 5111 is sucked in by the ejector effect, the high-calorie gas is mixed in advance at a constant air ratio of 0.8 to 1.0 and swirl-injected into the auxiliary combustion chamber 2. Ru. Therefore, the flame injected from the sub-combustion chamber becomes a high-temperature pilot flame, spreads toward the entrance side of the main combustion chamber, and is ejected, forming a high-temperature combustion zone. Therefore, even low-calorie gas, which is inherently difficult to burn and is even more combustible due to its twitch-rich combustion state, is easily ignited and stably combusted.

(Effects of the Invention) As is clear from the above description, the gas turbine combustor for low-calorie gas of the present invention is provided with a ceramic sub-combustion chamber equipped with an auxiliary burner on the inlet side of the main combustion chamber, and the sub-combustion chamber is equipped with an auxiliary burner. Since the main fuel injection nozzle and combustion air injection nozzle are arranged around the chamber outlet, a high-temperature flame is formed in the sub-combustion chamber, which does not require combustion air for cooling, and is then injected into a jet of low-calorie gas. Place it in the center of 1. It facilitates and stabilizes the combustion of low-calorie gas injected from its surroundings. That is, even if the low-calorie gas misfires, it will be ignited again by the high-temperature pilot flame spewing out from the auxiliary combustion chamber, and stable combustion will be maintained. In particular, in the combustor of the present invention, if high-calorie gas is burnt in the sub-combustion chamber, ignition becomes easy and this becomes a stable ignition source, so the supply of combustion air is reduced to achieve twin rich combustion. The generation of NOx can be suppressed to a low level. Moreover, 2
It is extremely rare for fuel systems to stop supplying fuel to both systems at the same time, and misfires caused by foreign substances such as water being mixed into the fuel can be prevented.

In addition, in the present invention, if the high-calorie combustion gas combusted in the sub-combustion chamber is swirled and injected into the main combustion chamber, the high-temperature flame injected from the sub-combustion chamber will spread in the main combustion chamber and cause the main combustion. The recirculation flow in the chamber 1, ie, the flame-holding mechanism, is not destroyed, so combustion is stabilized.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the center M showing an embodiment of the low-calorie gas turbine combustor of the present invention, Fig. 2 is an enlarged sectional view of the auxiliary combustion chamber, and Fig. 3 is a view indicated by the ■ arrow in Fig. 2. , FIG. 4 is a schematic explanatory diagram showing an embodiment of a pond sub-combustion chamber, and FIG. 5 is a schematic diagram of a conventional gas turbine combustor. 1...Main combustion chamber, 2...Sub-combustion chamber, 3...Main fuel injection nozzle, 4...Combustion air injection nozzle, 5...Auxiliary burner, 17.18...Ejector The diaphragm and partition plate that constitute: 19...Air supply port. Figure 3

Claims (6)

[Claims] (1) A low combustion engine characterized by having a ceramic auxiliary combustion chamber equipped with an auxiliary burner on the inlet side of the main combustion chamber, and arranging a main fuel injection nozzle and a combustion air injection nozzle around the outlet of the auxiliary combustion chamber. Gas turbine combustor for caloric gas. (2) A ceramic auxiliary combustion chamber equipped with an auxiliary burner is provided on the inlet side of the main combustion chamber, and a main fuel injection nozzle and a combustion air injection nozzle are arranged around the outlet of the auxiliary combustion chamber,
A gas turbine combustor for low-calorie gas, characterized in that high-calorie gas is combusted in the sub-combustion chamber. (3) The main combustion chamber burns low-calorie gas that accounts for 90% or more of the total generated heat, and the auxiliary combustion chamber burns 1 of the total generated heat.
The gas turbine combustor for low-calorie gas according to claim 2, characterized in that less than 0% of high-calorie gas is combusted. (4) A ceramic auxiliary combustion chamber equipped with an auxiliary burner is provided on the inlet side of the main combustion chamber, and a main fuel injection nozzle and a combustion air injection nozzle are arranged around the outlet of the auxiliary combustion chamber,
A gas turbine combustor for low-calorie gas, characterized in that high-calorie gas is combusted in the sub-combustion chamber, and is swirled within the sub-combustion chamber and injected toward the main combustion chamber. (5) Burn low-calorie gas of 90% or more of the total generated heat in the main combustion chamber, and 1 of the total generated heat in the auxiliary combustion chamber.
The gas turbine combustor for low-calorie gas according to claim 4, characterized in that less than 0% of high-calorie gas is combusted. (6) The low calorie according to claim 4, characterized in that the injection axis of the auxiliary burner in the auxiliary combustion chamber is inclined with respect to the central axis of the auxiliary combustion chamber, and the outlet portion of the auxiliary combustion chamber is opened to widen toward the end. Gas turbine combustor for gas.