JPH04131619A - Gas turbine combustion device - Google Patents

Abstract

PURPOSE:To improve a thermal efficiency under a partial load and reduce a concentration in discharging NO2 by a method wherein a flow rate control valve is installed at an inlet of an inner cylinder flow passage of air for making pre-mixture gas with fuel, a downstream side of the inner cylinder is provided with a bypass valve and then the opening of each of the flow rate control valve and the bypass valve is controlled in response to a flow rate of fuel. CONSTITUTION:A fuel flow rate F1 at a fuel nozzle 107 is measured by a flow meter 132, a fuel flow rate F2 at a fuel nozzle 101 is measured by a flow meter 134. These flow rates are corrected in references to a temperature of surrounding air and an amount of suction air of a compressor 121 so as to get corrected fuel flow rates F1* and F2*, respectively. Then, F1*+F2* is compared with a constant value K and when a relation of F1*+F2*<K is attained, as rotational angle of each of motors 152 and 162 is controlled in such a way that a flow rate control valve 104 is fully opened and a bypassing valve 105 is fully closed. In turn, when a relation of F1*+ F2*>K is attained, a fuel flow rate correction value F2* is compared with a constant value A and in turn a relation of F2*<A is attained, a rotational angle of each of motors 152 and 162 is controlled in such a way that a flow rate control valve 104 is partially opened and the bypassing valve 105 is partially closed. When a relation of F2*>A is attained, a rotational angle of each of motors 152 and 162 is controlled in such a way that opening of the flow rate control valve 104 is proportional to F2*/F2max* and the opening of the bypass valve 105 is proportional to (F2max*-F2max*)/F2max*.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas turbine combustor, and particularly to an air flow distribution control structure suitable for improving thermal efficiency and reducing No. The present invention also relates to a gas turbine combustor having a premixture formation promoting air supply structure.

[Prior Art] An example of a conventional gas turbine combustor having a structure for controlling the flow rate of air supplied to an inner cylinder is disclosed in Japanese Patent Application Laid-Open No. 63-217141.
This is shown in the publication No. FIG. 7 is a schematic sectional view showing an example of the conventional gas turbine combustor. In FIG. 7, fuel 130 from the fuel nozzle 101 and air 206 from the compressor enter through the inner cylinder external space 221 between the outer cylinder 103 and the inner cylinder 102 and enter from the air hole 202 into the premixing chamber 205. The mixture is mixed in the combustion chamber 220 to form a premixture.
burn inside. Fuel 13 from one fuel nozzle 107
1 is also burned while mixing with the air entering from the air hole 219 and the air from the premixing chamber 206, and the combustion gas 207 is
5124 into the turbine. The air hole 202 is provided with a flow control valve 1°4 for controlling the air flow rate in response to changes in the fuel flow rate. Therefore, at partial loads with low fuel flow, the amount of air required to form a combustible premixture decreases, so the flow rate control valve 104 is throttled to reduce the passage area of the air hole 202 to reduce the air flow flowing into the premixing chamber 205. Decrease. With this structure, the total area of the air holes in the inner cylinder is minimum at low loads and maximum at rated loads. On the other hand, the air flow rate does not change much even if the compressor inlet guide vane opening control is taken into consideration. Therefore, the lower the load, the faster the air flows into the inner cylinder 102.

Another example of a conventional gas turbine combustor having a structure for controlling the air flow rate supplied to the inner cylinder is disclosed in Japanese Patent Application Laid-Open No. 62-23342.
This is shown in Publication No. 5. FIG. 8 is a schematic sectional view showing another example of the conventional gas turbine combustor. In Fig. 8, the same reference numerals indicate corresponding parts throughout the drawings, and when a partial load with a small fuel supply amount occurs, the bypass valve 1
Open 05 and tail from air hole 201! 1j124 to reduce the air flow rate supplied to the inner cylinder 102.

As a result, the flow rate of air flowing into the premixing chamber 205 is relatively reduced, and the air is mixed with the fuel 130 from the fuel nozzle 101 to form a combustible air-fuel mixture. With this structure, the opening degree of the bypass valve 105 increases as the load decreases, so the total cost is $102.
And the total air hole area including the tail @124 becomes larger,
The speed of air flowing into the inner cylinder 102 becomes smaller.

[Problems to be Solved by the Invention] The above-mentioned conventional technology does not take into consideration the fact that the combustor pressure loss changes greatly during partial load of the gas turbine, resulting in a significant decrease in overall thermal efficiency and uneven premixture concentration. There was a problem that the emission value increased due to the No.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas turbine combustor in which the pressure loss of the combustor is kept almost constant throughout the entire load range of the gas turbine, the thermal efficiency is improved at partial load, and the concentration of NOx emissions is reduced.

[Means for Solving the Problems] In order to achieve the above object, the gas turbine combustor of the present invention is provided with a flow rate control valve for air for forming a premixture with fuel,
Additionally, a flow rate control valve (bypass valve) for air mixed with the combustion generated gas is provided.

Further, the bypass valve is provided between the combustor and other low pressure space.

Furthermore, in order to prevent the air flowing into the premixing chamber from drifting, a rectifying chamber is provided between the flow rate control valve for the air for forming the premixture gas and the air inlet of the premixing chamber.

Also, in order to increase the speed of air flowing into the premixing chamber,
In addition to the flow path through the flow control valve, an air flow path whose flow rate is not controlled is provided around the fuel nozzle.

[Function] In the gas turbine combustor, the premixture forming air flow rate control valve operates to supply air in a predetermined ratio range to the supplied fuel flow rate, and the bypass valve operates to remove unnecessary air for premixing. The combustion gas flows into the flow path, thereby reducing changes in the air inlet area including the inner cylinder and transition piece over the entire operating range of the gas turbine, and reducing changes in combustor pressure loss. In addition, by providing a bypass valve between the combustor and other low-pressure spaces, air unnecessary for premixing can be released to the outside of the combustor. The internal cylinder air flow rate corresponding to the decrease in combustor pressure drop decreases, and the change in combustor pressure loss becomes smaller.

Furthermore, a rectifying chamber installed between the premixing air flow rate control valve and the premixing chamber air inlet prevents uneven flow of air flowing into the premixing chamber, thereby making the fuel concentration distribution of the premixing uniform. become

In addition, high-speed air always flows through the air passage provided around the fuel nozzle and whose flow rate is not controlled, thereby promoting the mixing of fuel and air and making the fuel concentration distribution of the premixture uniform.

[Example] Examples of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a sectional view showing an embodiment of a gas turbine combustor according to the present invention. In FIG. 1, air 206 compressed by a compressor 121 having guide vanes 123 at its inlet that can control the suction flow rate flows through a passage formed by an outer cylinder 103 and an inner cylinder 102 in the direction of the arrow. Inner cylinder 10
2 is provided with an air hole 202 for combustion air, an air hole 201 for bypass air, and an air hole 219 for a pilot burner in addition to cooling air holes (not shown). The air hole 202 is provided with a flow rate control valve 104, and the air hole 201 is provided with a bypass valve 105. The flow rate control valve 104 is opened and closed by a link rotation motor 152 via a link mechanism consisting of a rotation shaft 150 and a link 151, and the bypass valve 105 is controlled to open and close by a link rotation motor 152 via a link mechanism consisting of a rotation shaft 160 and a link 161. Opening/closing is controlled by After the air flowing in from the air hole 202 is decelerated in the rectifying chamber 204, it flows into the cylindrical premixing chamber 205 through the air holes 217 and 218, and mixes with the fuel 130 supplied from the fuel nozzle 101 to form a premixed air. After being formed, it is combusted in the combustion chamber 220. Here, liquid fuel 130 is used as an example, and an air hole 209 is provided to form a passage that directly communicates the inner cylinder external space 22, 1 and the premixing chamber 205, and this air is supplied to the central passage 211 of the fuel nozzle 101 and the premixing chamber 205. The fuel flows into the premixing chamber 205 from the annular passage 210 provided on the outer periphery of the annular fuel passage 213 to promote atomization and premixing of the liquid fuel 130. Fuel 131 is also supplied from a fuel nozzle 107 provided at the center of one end of the inner cylinder, and is combusted in the combustion chamber 220 while being mixed with air from the air hole 219, and the combustion gas 207 is introduced into the turbine 122. The air hole 219 that communicates the inner cylinder outer space 221 and the combustion chamber 220 has a structure that forms a swirling flow. The fuel 130 supplied to the fuel nozzle 101 is controlled by a flow control valve 133, and the fuel 131 supplied to the fuel nozzle 107 is controlled by a flow control valve 135. Flowmeters 134 and 132 for fuels 130 and 131, respectively
The structure is such that the signal is output to the link rotation motors 152 and 162 of the flow control valve 104 and the bypass valve 105.

In the gas turbine combustor with the above configuration, the fuel nozzle 1 is used from ignition at startup to self-sustaining operation and low load operation.
Fuel 131 is supplied only from 07 and combusted in the combustion chamber 220. At this time, the air flow rate distribution is the same as that at the rated load, or the proportion of air passing through the premixing chamber 105 is slightly smaller than that at the rated load, and the bypass 105 is fully open or slightly open. One flow control valve 104 is fully open or slightly closed, and the total air hole area of the inner cylinder is approximately the same as at rated load. This combustion state is diffusion combustion,
The amount of fuel supplied from the fuel nozzle 107 is controlled by the flow rate control valve 133.
As the load increases, the NOx emission concentration exceeds the environmental regulations. Therefore, when increasing the load, it is considered that the combustion state is mainly premixed combustion, which is less likely to generate No. The flow rate is controlled by the flow rate control valve 135 so that the water is supplied.

At this time, after the fuel 130 supplied from the fuel nozzle 101 is premixed with air in the premixing chamber 205, it is transferred to the combustion chamber 220.
In order to achieve combustion within the combustion chamber, it is necessary to maintain the premixture concentration within a certain range, and the air flow rate must be controlled. Therefore, the flow rate of air flowing into the premixing chamber 205 is controlled by opening and closing the air flow rate control valve 104.
When attempting to oxidize O, the flow rate of air passing through the premixing chamber 205 becomes more than 50% of the total, and if premix combustion is attempted even during low load operation, the opening degree of the flow control valve 1°4 becomes smaller, causing the combustor If the pressure loss becomes too large and the thermal efficiency decreases, or if the guide vanes 123 are controlled to reduce the air flow rate, surging may occur in the compressor 121, so the opening degree of the bypass valve 105 may be increased. control so that the combustor pressure loss is within the allowable value. When increasing the load, the flow control valve 135 increases the flow rate of fuel supplied from the fuel nozzle 101, and the flow control valve 135 increases the flow rate of air flowing into the premixing chamber 205 in proportion to the flow rate.
04 is opened and the bypass valve 105 is closed.

Figure 2 shows the premixture forming air flow control valve 10 in Figure 1.
4 is a flowchart illustrating a procedure for opening/closing control of bypass valve 105 and bypass valve 105. FIG. In Figure 2, fuel nozzle 1
07 fuel flow rate F1 is measured by the flow meter 132, the fuel flow rate F2 of the fuel nozzle 101 is measured by the flow meter 134, and the fuel flow rate F is determined based on the atmospheric temperature and the intake air flow rate of the compressor 121.
l + F 2 is corrected to obtain the fuel flow rate correction value Fl”+F
Find 2*.

Next, the fuel flow rate correction value F-, the sum of F, F, and the bundle+F2* are compared with a constant value, and when F, "+F2 car<K, the flow control valve 104 is fully opened and the bypass valve 105 is fully closed. The rotation angle of each motor 152 is controlled to control the rotation angle of the motor 162 as shown in FIG.
>K, the fuel flow rate correction value F2x is compared with a constant value A, and when F2X (A), the rotation of each motor 152 is adjusted such that the flow rate control valve 104 is partially closed and the bypass valve 105 is partially closed. The rotation angle of the motor 162 is controlled by controlling the angle.Furthermore, when F2''>A, the flow control valve 1
04 is proportional to F 2"/F z'vaax, and the opening degree of the bypass valve 105 is set as (F 2"1.laχ-F
The rotation angle of each motor 152 is controlled so as to be proportional to 2"/F 2"ma2, and the rotation speed of the motor 162 is controlled.

FIG. 3 is a characteristic diagram illustrating the relationship between the opening degrees of the premixture forming air flow rate control valve 104 and the bypass valve 105 in FIG. 1 (FIG. 2) and the fuel flow rate F2x of the fuel nozzle 101. In FIG. 3, the opening degree (%) of the flow rate control valve 104 and the bypass valve 105 in FIG.
l''+F2° is F11+F2'':>K, as shown in FIG. The opening degree (%) of the bypass valve 105 is controlled to be partially (25%), and the opening degree (%) of the bypass valve 105 is controlled partially (75%).
The fuel flow rate correction value F28 (%) of the fuel nozzle 101 is - constant 1i! A (25%) or more and up to the maximum value F2K (100%), the opening degree (%) of the flow rate control valve 104 is the same as that of the fuel nozzle 101.
The opening degree (%) of the bypass valve 105 is controlled in proportion to the fuel flow rate of the fuel nozzle 101 (F 2 ”+aa2- F 2) / F 2”m
It is controlled from partially closed (75%) to fully closed (0%) in proportion to aX.

4(a) and 4(b) are partial top views of the outside and inside of the outer cylinder 103, illustrating the opening/closing mechanism of the flow rate control valve 104 for forming a premixed gas shown in FIG. 1. In FIGS. 4(a) and 4(b), on the outside of the outer cylinder 103 shown in FIG. 4(a), one end of a rotating shaft 150 rotates in the direction of the arrow and a link 151 moves in the direction of the arrow by the link rotation motor 152. constitutes a link mechanism with links 155 and 156, as shown in Fig. 4 (
Inside the outer WJ 103 shown in b), the other end of the rotating shaft 150 rotates in the direction of the arrow and the air hole 202 moves in the direction of the arrow.
The flow rate control valve 104 that controls opening and closing of the flow rate is connected to the link 153.
, 154 constitute a link mechanism. Similarly, in the opening/closing mechanism of the bypass valve 105, on the outside of the outer cylinder 103, one end of the rotating shaft 160 and a link 161 moved by a link rotation motor 162 constitute a link mechanism, and the outer flil○3
Inside the rotating shaft 160, there is a bypass valve 1 that moves in the direction of the arrow in FIG.
05 constitutes a link mechanism.

According to this embodiment, when the air flow rate of the air hole 202 and the air hole 201 is controlled by the flow rate control valve 104 and the bypass valve 105 of the premixture forming air as described above, the inner cylinder outside 221 and the premixing chamber 205 can be kept almost constant, and the air flow rate supplied to the premixing chamber 205 through the air hole 209 is almost constant, so that the liquid fuel can be atomized and premixed with air. gas turbine 1
22 can be maintained in good condition regardless of the load,
By keeping the premixture fuel concentration at a concentration that allows stable combustion at a low combustion gas temperature, it is possible to reduce NOx.

Furthermore, when the liquid fuel combustion in FIG. 1 is replaced with gas fuel combustion, high-speed air is constantly supplied from the air hole 209, so that the air flow rate from the air holes 217, 218 and the gas flow rate from the fuel nozzle 101 are reduced. Mixing is promoted even in low-load conditions where the fuel is slow, and it is possible to burn a premixture without locally high-concentration fuel, thereby reducing NOx.

FIG. 5 is a schematic sectional view showing another embodiment of the gas turbine combustor according to the present invention. FIG. 5 shows an embodiment in which the bypass valve 105 and air hole 201 of FIG. 1 are provided in the transition piece 124. The gas turbine can operate normally by mixing the air not involved in combustion at low load with the combustion gas 207 between the position where the combustion reaction is completed in the combustion chamber 220 and the turbine nozzle inlet. Therefore, as shown in FIG.
01 can be provided.

FIG. 6 is a schematic cross-sectional view showing still another embodiment of the gas turbine combustor according to the present invention. In Figure 6, the first
The bypass valve 105 and air hole 201 shown in the figure are connected to the outer cylinder 103.
An example provided in the figure is shown below.

In a gas turbine combustor that mainly performs fuel lean premix combustion, the concentration of air before mixing with the air from the air holes 201 is approximately constant throughout the entire load range. Premixed air flow control valve 1
If 04 is reduced to a part, the area of the air holes in the inner cylinder will decrease, and if all the air is allowed to flow, the pressure loss in the combustor section will increase. Therefore, considering controlling the air flow rate supplied to the combustor according to the gas turbine load, the bypass valve 1o5 and air hole 201 shown in FIGS. 1 and 5 are provided in the outer cylinder 103 as shown in FIG. Air that does not need to be supplied to the combustor during load is directed to the exhaust duct downstream of the turbine.

According to this embodiment, the exhaust gas concentration and the combustor pressure loss become appropriate, but the thermal efficiency decreases because the gas flow rate passing through the turbine decreases.

The air passing through the bypass valve 105 in FIG.
Although it is conceivable to supply it after the second stage, the same effect as the embodiment shown in FIG. 6 can be obtained.

[Effects of the Invention] According to the present invention, by controlling the opening degrees of the two flow control valves according to the fuel flow rate, the combustion air flow rate can be controlled according to the gas turbine load without significantly changing the combustor pressure loss. This has the effect of improving thermal efficiency during partial load.

In addition, since the air flow rate supplied to the combustor can be controlled proportionally to the gas turbine load, the turbine outlet gas temperature is always kept high, which has the effect of improving the partial load thermal efficiency of a combined power generation system equipped with an exhaust heat recovery boiler. .

Furthermore, since air can be uniformly supplied to the premixing chamber, it becomes easier to form a homogeneous air-fuel mixture, which has the effect of reducing the Nox concentration during combustion.

Furthermore, since high-speed air can always be supplied to the premixing chamber, the performance of splitting liquid fuel into fine particles is improved, promoting the mixing of air and fuel, and achieving low NOx combustion. In the case of gas fuel, mixing with air can be promoted, resulting in low NOx combustion.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of a gas turbine combustor according to the present invention, FIG. 2 is a flowchart illustrating the opening/closing control procedure of the flow control valve 104 and bypass valve 105 shown in FIG. 1, and FIG. Characteristic diagrams illustrating the relationship between the opening degrees of the flow rate control valve 104 and the bypass valve 105 and the fuel flow rate Fz of the fuel nozzle 101 in FIG. 1 (FIG. 2), FIGS. 4(a) and (b)
) is a partial top view of the outside and inside of the outer cylinder 103 illustrating the opening/closing mechanism of the flow control valve 104 in FIG. 1, and FIG. 5 is a schematic sectional view showing another embodiment of the gas turbine combustor according to the present invention. FIG. 6 is a schematic sectional view showing still another embodiment of a gas turbine combustor according to the present invention, FIG. 7 is a schematic sectional view showing an example of a conventional gas turbine combustor, and FIG. 8 is a schematic sectional view showing an example of a conventional gas turbine combustor. It is a schematic sectional view showing other examples of a combustor. 101... Fuel nozzle, 102... Inner cylinder, 103...
...Outer cylinder, 104...Flow rate control valve, 105...Flow rate control valve (bypass valve), '107...Fuel nozzle, 12
1...Compressor, 122...Turbine, 124...
Tail piece, 201.202... Air hole, 204... Rectification chamber, 205... Premixing chamber, 209... Air hole, 22
0... Combustion chamber. Hitachi Urasakusho Co., Ltd. Representative Patent Attorney Tadashi Akimoto Jitsuzuzusuzuzuzuzu (Q) (b)

Claims (1)

[Claims] 1. An inner cylinder that mixes and burns high-pressure air supplied from a compressor and fuel supplied from a separate system in its internal space;
Premixing with fuel is performed in a gas turbine combustor that consists of a fuel nozzle that supplies fuel into the inner cylinder, a transition pipe that guides the combustion gas generated inside the inner cylinder to the downstream turbine, and an outer cylinder that houses these. A first flow control valve is provided at the inlet of the inner cylinder flow path for air to form air, and a second flow control valve is provided at the downstream side of the inner cylinder or at the transition pipe, and the first and second flow control valves are provided. A gas turbine combustor characterized in that the opening degree of the gas turbine combustor is controlled according to the fuel flow rate. 2. The opening degree of the first flow control valve is increased approximately in proportion to the fuel flow rate above a predetermined value, and the opening degree of the second flow control valve is increased approximately in inverse proportion to the fuel flow rate above the predetermined value. The gas turbine combustor according to claim 1, characterized in that the gas turbine combustor is configured to reduce the number of combustors. 3. Claim 1 or Claim 2, characterized in that the second flow rate control valve is provided at a connecting portion between the outer cylinder and the combustor external low pressure chamber.
Gas turbine combustor as described. 4. Any one of claims 1 to 3, characterized in that a rectifying chamber is provided between the first flow rate control valve and the air inlet of the inner cylinder premixing chamber to prevent uneven flow of incoming air. The gas turbine combustor according to item 1. 5. Claims 1 to 4, characterized in that an air flow path is provided around the fuel nozzle to communicate the outside of the inner cylinder and the premixing chamber.
The gas turbine combustor according to any one of the above.