CN101169251B - Gas turbine multiple nozzle for dilution diffusion and combustion of synthesis gas - Google Patents

Abstract

The invention is a multi-nozzle dilution and diffusion combustion system suitable for syngas with low pollutant discharge and low noise. The arrangement of one liquid fuel spray combustion nozzle and five syngas nozzles with the same rotation direction can carry out dilution diffusion combustion. The fuel swirler and the air swirler are respectively in the form of tangential holes and vane-type radial swirlers, and the direction of rotation between them is opposite. The blade adopts two special structures of slotted back and tangential hole.

Description

Diluted Diffusion Combustion of Gas Turbine Syngas with Multiple Nozzles

technical field

The invention relates to the technical field of gas turbine combustors, in particular to the field of gas turbine combustors using syngas as fuel.

Background technique

With the rapid development of my country's economy, the pressure on energy and environment is becoming increasingly urgent. The relatively limited reserves of oil and natural gas and the relative abundance of coal resources determine my country's coal-based energy structure. However, coal is prone to produce a large amount of pollutants in the process of traditional power generation and utilization, and is the main source of environmental pollution in my country. Among them, IGCC opens up a new way for the clean utilization of coal and a clean and efficient power generation system. IGCC first converts coal gas into syngas, and after purification, the syngas is passed into the combustor of the gas turbine for combustion, and then drives the turbine to generate power. However, traditional gas turbine combustors are mainly divided into lean premixed combustion and diffusion combustion, but the current two methods are not suitable for syngas combustion. Due to the characteristics of syngas (containing hydrogen and more carbon monoxide), if the lean premixed combustion method is used, problems such as combustion instability, flashback and thermoacoustic oscillation will occur; Diffusion combustion will produce a large amount of NO _x , and high hydrogen content will lead to high combustion noise. Therefore, it is necessary to develop a gas turbine combustion system suitable for burning syngas with low pollutant emission and low noise.

Contents of the invention

The object of the present invention is to provide a gas turbine syngas dilution and diffusion combustion multi-nozzle, which is used in a low _NOx emission and low noise multi-nozzle diffusion combustion system suitable for synthesis gas characteristics. Due to the adoption of diffusion combustion technology, there are no problems such as combustion instability, flashback and thermoacoustic oscillation in lean premixed combustion.

In order to achieve the above object, the technical solution adopted in the present invention is: a multi-nozzle for gas turbine synthesis gas dilution and diffusion combustion, which is suitable for a low-pollutant emission and low-noise synthesis gas combustion system; it adopts a multi-nozzle structure; it adopts fuel dilution or Air-diluted diffusion combustion method; radial vane air swirler and tangential hole fuel swirler are used.

The multi-nozzles for the dilution and diffusion combustion of syngas have a plurality of syngas nozzles in the circumferential direction of the liquid fuel spray nozzles, and the rotation direction of each syngas nozzle is the same, so as to form a recirculation zone suitable for syngas combustion.

In the syngas dilution and diffusion combustion multi-nozzle, the air swirler and the fuel swirl are opposite in direction of rotation.

The syngas dilution and diffusion combustion multi-nozzle uses a diluent to dilute fuel or air, or simultaneously dilute fuel and air to achieve low _NOx emissions.

Said syngas dilution and diffusion combustion multi-nozzle, said diluent is water vapor, nitrogen or carbon dioxide.

The multi-nozzle for syngas dilution and diffusion combustion is suitable for combusting syngas with different components and different calorific values.

In the syngas dilution and diffusion combustion multi-nozzle, the air swirler adopts two types of specially processed vane structures: slotted type or tangential hole type, so as to improve the temperature field distribution of the combustion chamber.

In the syngas dilution and diffusion combustion multi-nozzle, the plurality of syngas nozzles are arranged in such a way that a liquid fuel spray combustion nozzle is in the middle.

The syngas dilution and diffusion combustion multi-nozzle, the fuel of the liquid fuel spray combustion nozzle is liquid fuel methanol or diesel.

In the multi-nozzle for the dilution and diffusion combustion of syngas, the number of syngas nozzles is five.

The effect of the present invention is to realize a set of multi-nozzle system, so that the combustion of syngas is stable and efficient, and at the same time, the goals of low pollutant emission and low noise are achieved.

Description of drawings

Fig. 1 is a schematic diagram of nozzle arrangement of the present invention;

Fig. 2 is a structural schematic diagram of a single syngas nozzle;

Fig. 3 is a schematic structural view of a slotted blade, wherein: Fig. 3a is a front view; Fig. 3b is a rear view; Fig. 3c is a left view;

Fig. 4 is a schematic view of the structure of a blade with tangential holes, wherein: Fig. 4a is a front view; Fig. 4b is a rear view; Fig. 4c is a left view.

Detailed ways

In order to solve the problem of combustion chamber noise, the present invention adopts a multi-fuel nozzle combustion system, which has the advantage of not only significantly reducing the noise of the combustion chamber, but also reducing the wear and tear of the combustion chamber and reducing operating costs. According to the arrangement of nozzles, the multi-nozzle form is selected as one liquid fuel spray combustion nozzle in the middle and five syngas nozzles in the circumferential direction. Such nozzle arrangement can not only utilize the area of the end cover of the flame tube to the greatest extent, but also avoid the mutual interference between the flames of the nozzles to the greatest extent.

In view of the great difficulty in combusting the hydrogen-rich synthesis gas in the lean premixed combustor, the present invention adopts the diffusion combustion method. High _NOx emissions are due to the high adiabatic flame temperature of the syngas.

The invention adopts the way of dilution combustion to reduce _NOx emission in the combustion process. This is done by injecting nitrogen, carbon dioxide or water vapor+ into the fuel or the air. For multi-nozzle combustion systems, dilution combustion can significantly reduce _NOx emissions without significantly increasing the combustion chamber noise level.

Diluted syngas becomes low calorific value syngas, which has combustion stability problems. Therefore, the present invention adopts the following means to increase the recirculation zone and strengthen blending, so as to achieve the purpose of stably and efficiently burning diluted syngas.

The air swirler adopts vane type radial swirler, and the fuel swirler adopts tangential hole type swirler. Radial swirlers are more suitable for counter-flow combustors, which can achieve high swirl numbers with less pressure loss. The direction of the fuel and air swirls is opposite, which can produce a larger recirculation zone than the same swirl flow. The main reason is that the strong shear on the boundary of the inner and outer swirls leads to the diffusion and dissipation of the inner swirl, which leads to Stronger reverse pressure gradient and thus enhanced recirculation. This allows for better mixing and a large recirculation zone at lower swirl numbers. The rotation direction of each nozzle is the same, because the tangential velocity of two adjacent nozzles is opposite, which can increase the size of the recirculation zone, which is beneficial to the stability of the flame and the complete combustion. Adding divergent extensions to the nozzle outlet has the combined effect of increasing the radial separation between the axial and tangential velocity peaks and increasing the reverse mass flow.

The blades of the radial air swirler adopt two structural modes of slotting on the back of the blade or tangential holes. Such a blade structure can increase the turbulence intensity at the outlet of the swirl blade by generating a small-scale turbulent structure, which can make the fuel and air mix quickly and uniformly, which is conducive to more complete combustion and lower local flame temperature, so it is beneficial to reduce CO and _NOx . Discharge, improve the temperature field distribution at the outlet of the flame tube.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

In the nozzle layout diagram shown in Figure 1, a liquid fuel spray combustion nozzle 11 is arranged at the center of the end cover 1, and five syngas nozzles 12 are evenly distributed around it, and the rotation direction of each syngas nozzle 12 is the same .

In the structural diagram of a single syngas nozzle 12 shown in Figure 2, the fuel swirler 3 is a tangential hole swirler, the air swirler 4 is a vane radial swirler, and the fuel swirler 3 and the air swirler The rotation direction of flow device 4 is opposite. An expansion type extension section 5 is installed at the outlet of the fuel swirler 3 .

In the structural diagram of a single syngas nozzle 12 shown in Figure 2, when performing dilution diffusion combustion, a diluent (nitrogen, carbon dioxide or water vapor) is injected into the air or fuel in advance, and after the air or fuel is uniformly mixed with the diluent Enter the air swirler 4 or the fuel swirler 3 respectively for combustion, and the combustion schematic diagram is shown as 2 in Fig. 1 .

The air swirler 4 adopts a vane-type radial swirler, and its vane structure adopts two structures: the back slot type and the tangential hole type, as shown in Figures 3 and 4, respectively, where Figures 3a and 4a are front views , Figure 3b, Figure 4b is a rear view, Figure 3c, Figure 4c is a left view. For the back slotted blade 13, each triangular groove is the same, the cone angle used by the triangular groove ranges from 30° to 120°, and the depth of the cone valley is 1/3 to 1/2 of the thickness of the top of the blade. For the slotted blade 13 on the back, the air flows in from the top of the blade 13, flows out from the bottom of the blade 13 through the triangular grooves arranged in a staggered manner; The number of holes is 4 to 6, and several tangential holes are opened on the back of the blade to penetrate the round hole. When burning, part of the air flows in from the top of the blade 14, flows out along the back of the blade 14, and part of the air enters from the round hole on the side of the blade 14. , flowing out from the tangential holes arranged on the back of the blade 14.

Claims (9)

1. a gas turbine multiple nozzle dilution, diffusion and combustion system for synthesis gas is applicable to low pollutant emission, low noise synthesis gas combustion system; It is characterized in that: adopt the multiinjector structure; Adopt the diffusion combustion mode of fuel dilution or air dilution; Adopt radial blade formula air cyclone, tangential cellular type fuel swirl device;

Described multiple nozzle dilution, diffusion and combustion system for synthesis gas, wherein: described multiinjector structure is that the week of liquid fuel within spray nozzle upwards is a plurality of synthesis gas nozzles, and the rotation direction of each synthesis gas nozzle is identical, thereby forms the recirculating zone that is fit to the synthesis gas burning.

2. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 1 is characterized in that: the rotation direction of described air cyclone and fuel swirl device is opposite.

3. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 1 is characterized in that: described fuel dilution or air dilution, and be to adopt diluent dilution fuel or air, or dilute fuel and air simultaneously, reach low NO _xDischarging.

4. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 3 is characterized in that: described diluent is water vapour, nitrogen or carbon dioxide.

5. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 1 is characterized in that: the synthesis gas that is applicable to burning different component, different calorific values.

6. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 1 is characterized in that: described air cyclone is to adopt open flume type or open the blade construction form of two kinds of special processing of tangential cellular type, to improve the chamber temperature field distribution.

7. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 1 is characterized in that: the centre of described a plurality of synthesis gas nozzles is a liquid fuel atomizing combustion nozzle.

8. multiple nozzle dilution, diffusion and combustion system for synthesis gas according to claim 7 is characterized in that: the fuel of described liquid fuel atomizing combustion nozzle is liquid fuel carbinol or diesel oil.

9. according to claim 1 or 7 described multiple nozzle dilution, diffusion and combustion system for synthesis gas, it is characterized in that: described a plurality of synthesis gas nozzles are five.

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