JPS6086328A - Catalyst burner - Google Patents

Abstract

PURPOSE:To obtain a constant catalyst combustion temperature by advancing and retreating a pre-combustion burner to change the amount of combustion air and to prevent blow off by providing the pre-combustion burner with a holder. CONSTITUTION:A cylindrical casing 1 is provided with an inner tube 2 concentrically at the inside thereof and the inner tube 2 is arranged with the catalyst 9 at the intermediate part in the inner tube 2 while compressed air for combustion is passed through a path 14 between the casing 1 and the inner tube 2 to flow it into the inner tube 2 from the opening 15 of the end face of the inner tube. In such catalyst burner, the inner tube 2 is provided with a bypass air port 10 at the downstream side of the catalyst and a fuel nozzle 12 is opened at the upstream side of the same. The pre-combustion burner 5, consisting of a tubular holder 4 and a conical section 4a, is provided at the end in the inner tube and the conical section 4a is advanced or retreated in the opening 15 to change the amount of inflow air. As a result, the catalyst combustion temperature will never be changed even in case the output of a turbine is fluctuated and blow off is eliminated even in case of change of the flow amount of air whereby the stabilized pre-combustion may be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a combustor for a gas turbine using a catalytic combustion method, and particularly to a catalytic combustor that can control the fuel-air ratio upstream of a catalyst.

[Technical background of the invention and its problems] Today, there is a strong desire to reduce harmful air pollutants such as nitrogen oxides (NOx) generated from gas turbine combustors, and various methods are being used to reduce NOx. There is.

Conventional gas turbine combustors have used a method of injecting water or steam to lower the combustion temperature and suppress thermal NOx. However, in order to further reduce NOx and enable high-temperature, high-efficiency operation, The catalytic combustion method is said to be effective for this purpose.

A catalytic combustor is a honeycomb-shaped ceramic base with a highly effective catalyst added to it, which is installed in the middle of the combustor's inner cylinder.The combustor is preheated to several hundred degrees Celsius and passes through the air-fuel mixture, which has been preheated to several hundred degrees Celsius and mixed sufficiently uniformly. The combustion is performed by

The catalytic reaction has limits on the temperature of the mixture supplied to it, the lower limit being the lowest temperature at which the catalytic reaction occurs, and the upper limit being the temperature at which the catalyst itself deteriorates. It must be possible to set an operating schedule based on the load, and the catalyst combustion temperature will not change even if the load fluctuates! L cannot be.

However, a catalytic combustor that satisfies these conditions has not yet been realized.

[Object of the Invention] The present invention has been developed based on the above considerations, and the catalyst combustion temperature does not change even when the turbine output fluctuates, and there is no blow-out even when the air flow rate changes and is stable. It is an object of the present invention to provide a catalytic combustor with a preheating burner that can sustain precombustion.

[Summary of the Invention] In order to achieve the above object, the present invention provides a bypass air hole in the combustor inner cylinder on the downstream side of the catalyst, opens a fuel nozzle on the upstream side, and provides a bypass air hole in the inner cylinder at the end of the inner cylinder. A preheating burner consisting of a cylindrical holder and a conical portion is provided, and the amount of incoming air is varied by moving the conical portion back and forth within an opening in the end face of the inner cylinder.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows a combustor according to the present invention, in which a cylindrical casing 1 and an inner cylinder 2 placed inside the casing 1 are shown.
A preheating burner 5 having a holder 4 having a precombustion air hole 3 and movable in the axial direction is provided at the inner end of the inner cylinder 2. One end of this preheating burner opens inside the inner cylinder 2, and the other end is connected to a preheating fuel supply pipe 6 and an outer pipe 7 that protects the preheating fuel supply pipe 6. A swirler 8 is attached to the outer surface of the holder 4 to support the preheating burner 5 and swirl the air in order to improve mixing with the catalyst fuel. Further, a catalyst 9 is disposed in the center of the inner cylinder 2, a bypass air hole 10 is disposed on the downstream side of the catalyst 9, and an external igniter 11 and a fuel nozzle 12 for catalytic combustion are disposed on the upstream side. Ru. The preheating burner 5 consists of a conical part 4a to which the outer pipe 7 of the precombustion fuel supply pipe is connected, and a cylindrical holder 4, and the conical part 4a is provided with a plurality of precombustion air holes 3. Further, a swirler 13 for creating a swirling flow is provided inside the holder 4.

Compressed air supplied from the compressor is delivered to the casing 1 and inner cylinder 2.
The preheating burner 5 passes through the passage 14 between the
air from the air hole 3 of the preheating burner 5 to the β part, and passes through the α part through the gap formed between the outer peripheral surface of the conical part 4a of the preheating burner 5 and the opening 15 of the inner cylinder 2 (see Fig. 2), and enters the combustion chamber. Supplied. The preheating fuel is injected into the r section of the preheating burner 5 from the fuel supply pipe 6 having a double pipe structure and mixed with compressed air.
It is ignited by the igniter 11. The burner position at the time of ignition is in the backward position (left side) as shown in Figure 2 (a),
The pressure at the combustion air inlet (combustor head) is high, and the combustion air is introduced from the air hole 10 downstream of the catalyst 9 and supplied to the turbine. After igniting with the igniter 11 in this state, the fuel in the preheating burner is increased until the preheating temperature necessary for catalytic combustion is reached, and after reaching the catalytic combustion temperature, the preheating burner 5 is moved forward (moved to the right) and at the same time 2
Fuel is injected from the fuel nozzle 12 to start catalytic combustion.

Thereafter, as the load increases, the flow rate from the second fuel nozzle is increased, and the preheating burner 5 is moved forward until the state shown in Fig. 2(b) is reached. (Fig. 2 (C)). In this state, the area of the combustion air inlet (combustor head) becomes large, so the pressure becomes low, and until then the catalyst downstream air hole 10
The air that was previously bypassed is now introduced from the combustor head. At this time, the air flow rate in the combustion chamber reaches its maximum, but the air flow rate entering the β section of the preheating burner 5 hardly changes, and the fuel-air ratio at the r section does not decrease. Due to the holder 4 around the upper r section, it is not affected by the large amount of rising air flowing through the alpha section. Therefore, the preheating burner 5 can always maintain stable precombustion from a low load to a maximum load, and no blowout occurs even if the amount of air flowing into the combustor head increases extremely.

[Effects of the Invention] As described above, according to the present invention, since the amount of combustion air is changed by moving the preheating burner back and forth, it is possible to always obtain a constant catalytic combustion temperature even when the load fluctuates (when the fuel flow rate fluctuates). A catalytic combustor is obtained in which a fuel-air ratio can be created, and blow-out can be prevented by providing a holder on the preheating burner, so that stable preheating is always possible over the entire operating range.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view showing the operation of the preheating burner shown in the figure. DESCRIPTION OF SYMBOLS 1... Casing 2... Inner cylinder 4... Holder 48... Conical part 5... Preheating burner 9... Catalyst 10... Bypass air hole 12... Fuel nozzle 14
...Aisle 15...Opening agent Patent attorney Noriyuki Chika (and 1 other person) 2nd (α) (e) Ru141- (C) 5

Claims (1)

[Claims] It includes a cylindrical casing, an inner cylinder arranged concentrically inside the casing, and a catalyst arranged in the middle of the inner cylinder, and compressed air for combustion is passed through a passage between the casing and the inner cylinder. In a catalytic combustor of a type in which the air flows through the inner cylinder and flows into the inner cylinder from an opening on an end face of the inner cylinder, a bypass air hole is provided on the downstream side of the catalyst with respect to the inner cylinder, and a solvent nozzle is opened on the upstream side, A preheating burner consisting of a cylindrical holder and a conical part is provided at the end of the inner cylinder, and the amount of incoming air is changed by moving the conical part back and forth within the opening of the end face of the inner cylinder. catalytic combustor.