RU2145669C1 - Method of operation of gas turbine engine and fire unit for combustion of fuel mixture - Google Patents

Abstract

FIELD: mechanical engineering; gas turbine engines. SUBSTANCE: method of operation of gas turbine engine comes to simultaneous combustion of liquid fuel and natural gas delivered in ratio G_g/(G_g+G_lf) = 0,5-0,7, where G_g is gas consumption and G_lf is liquid fuel consumption. Fire unit for combustion of liquid and gas fuels has liquid centrifugal nozzle built into cylindrical gas manifold with gas supply holes, air swirler and vortex mixer. Inner surface of vortex mixer, directly after air swirler, is made as confusing tube changing into cylindrical neck. Axes of gas supply holes in gas manifold are orientated to confusing tube generating line. Geometrical characteristic of liquid centrifugal nozzle and its position are designed to provided intersection of atomized fuel cone on initial section of flow with cylindrical neck of vortex mixer. EFFECT: reduced harmful effluents. 3 cl, 2 dwg

Description

 The invention relates to gas turbine engines and installations for various purposes and can be used in aviation, transport, ship, locomotive and stationary power plants.

A method of operating a gas turbine engine, based on the feed to the combustor and burning the liquid fuel (kerosene, diesel fuel) or gas with the simultaneous injection into the primary zone of the chamber well atomized water to reduce harmful to human emissions of nitrogen oxides NO _x (see., E.g., A. Lefebvre "Processes in the combustion chamber of a gas turbine engine", Moscow, Mir, 1986, p. 500).

However, a reduction in NO _x emissions, in this case, is associated with a significant increase in emissions of another harmful compound - carbon monoxide CO (see ibid., P. 499).

 In addition, the disadvantage of this method of engine operation is the preparation and storage of large quantities of distilled water.

 A known method of operation of a gas turbine engine, based on the supply to the combustion chamber and combustion of gas while supplying steam to the combustion zone (see, for example, Heat Power Engineering, 1992, No. 9).

 The supply of steam to the combustion zone, which is then released into the atmosphere, sharply limits the area of use of gas turbine engines in the “waterless” regions, and large additional costs for generating steam are always required.

Plants operating in this way have a fairly high level of emissions of NO _x and CO.

The issue of reducing nitric oxide emissions has received particular attention. The maximum permissible concentration (MPC) of nitrogen oxides is established. The most stable is nitrogen dioxide, into which all other oxides can pass. Therefore, the established MPC norms are given for the sum of all nitrogen oxides in terms of NO ₂ . This total value of all oxides is designated as NO _x .

 Three types of characteristics are used to indicate the level of emission of nitrogen oxides.

(г/кг топлива)
смешанная концентрация -

(г/нм³)
объемная концентрация -

(ppm).weight concentration -

(g / kg fuel)
mixed concentration -

(g / nm ³ )
volume concentration -

(ppm).

The ratio between these units, corresponding to the regulatory requirement of a 15% oxygen content in combustion products, is as follows:
1 g / kg fuel = 21.8 mg / nm ³ = 11.2 ppm.

 There is also known, selected for the prototype, the method of operation of a gas turbine engine (installation), based on the supply to the combustion chamber and burning at the same time liquid fuel (kerosene, diesel fuel) and natural gas.

 There is also a known fire unit adopted as a prototype that implements a known method of engine operation, comprising a liquid centrifugal nozzle integrated in a gas cylindrical manifold with gas supply openings, a swirler and a vortex mixer (front-end device). See, for example: 1) S.P. Izotov OA Rudakov et al. "Aircraft gas turbine engines in surface installations", L., Mashinostroenie, 1984, p. 96. 2) N.A.Sherlygin, V.G.Shakhverdov "Design and operation of aircraft gas turbine engines", Engineering, Moscow, 1969, p. 109.

 However, the known method of operation and the device for its implementation do not provide the established maximum permissible concentration of nitrogen oxides of 25 ppm.

The objective of the present invention is to reduce NO _x emissions without increasing CO emissions.

где G_г - расход газа;
G_ж.т - расход жидкого топлива.The solution to this problem is achieved by the fact that liquid fuel and natural gas are supplied simultaneously to the combustion chamber of a gas turbine engine through a firing unit in the ratio

where G _g - gas consumption;
G _z.t - liquid fuel consumption.

A significant difference of the proposed method of operation of a gas turbine engine is that with the specified ratio of the supply through the fire unit to the combustion chamber and the combustion of liquid fuel and natural gas, the emission of NO _x is minimal. There is no increase in CO emissions.

This is evidenced by the experimental data shown in FIG. 1, where the abscissa shows the ratio of liquid fuel to natural gas consumption, and the ordinate shows the levels of NO _x and CO emissions. The experiment was carried out while satisfying the regulatory requirement of a 15% oxygen content in the combustion products, with a degree in the compressor Pc = 10, air temperature behind the compressor 609 K. Completeness of combustion η _к = 0.999.

Processing of experimental data allows us to represent the dependence of the level of NO _x emissions on the ratio of the consumption of liquid fuel and natural gas by the equation:
y = 96.45 - 268x + 225.53 x ² .

The graph shows that the lowest (and less than 25 ppm) level of nitrogen oxide emission occurs at G _g / (G _g + G _z.t ) = 0.5 ... 0.7. The emission of carbon monoxide does not change.

 In the proposed device for implementing the method of operation of a gas turbine engine, the problem is solved in that in a firing unit containing a liquid centrifugal nozzle integrated in a gas cylindrical manifold with gas supply openings, an air swirl and a vortex mixer, the inner surface of the vortex mixer, directly behind the air swirl, made confuser, turning into a cylindrical neck, and the axis of the gas supply holes in the gas manifold are oriented to the confuser generatrix, and The geometric characteristics of the liquid centrifugal nozzle and its location in the firing unit are designed in such a way that the spray of fuel intersects in the upstream section with the cylindrical neck of the vortex mixer.

 An example implementation of the invention is presented in FIG. 2, where a longitudinal section is given of a firing unit for burning a mixture of fuels as a combustion of a gas turbine engine.

 The firing unit 1 is mounted in the housing of the combustion chamber 2.

 The firing unit 1 comprises a liquid centrifugal nozzle 3 for supplying liquid fuel integrated in a gas cylindrical manifold 4 with an opening 5 for supplying natural gas.

 To form a mixture of fuels and air, an aerodynamic air swirl 6 and a vortex mixer 7 are provided located at the entrance to the flame tube 8. Moreover, the inner surface of the vortex mixer 7, directly behind the air swirl 6, is made confuser, turning into a cylindrical neck, and the axis of the feed openings gas 5 in the gas manifold 4 are oriented to the generatrix of the confuser of the vortex mixer 7.

Through the firing unit 1, natural gas and liquid fuel are simultaneously supplied to the combustion chamber 2 in the ratio G _g / (G _g + G _z.t ) = 0.5 ... 0.7.

 Liquid fuel is fed through a liquid centrifugal nozzle 3, and natural gas is supplied through a collector 4 and openings 5.

 The air required to burn the fuel mixture passes through the aerodynamic swirl 6 and then enters the vortex mixer 7, placed at the entrance to the flame tube 8.

 To improve mixture formation, liquid fuel at a calculated angle of the spray pattern is fed to the section of the cylindrical mouth that is initial in the flow, and natural gas is fed to the vortex mixer confuser generatrix.

 The proposed method of operation of a gas turbine engine and a firing unit for burning a mixture of fuels provide a low level of emission of nitrogen oxides without increasing the emission of carbon monoxide.

 The use of the invention will significantly improve the environmental cleanliness of the exhaust gases of high temperature gas turbine engines.

Claims (2)

1. The method of operation of a gas turbine engine based on the supply of liquid fuel and natural gas to the combustion chamber and combustion at the same time, characterized in that liquid fuel and natural gas are supplied in a ratio of G _g / (G _g + G _z.t ) = 0.5 - 0.7, where G _g is the gas flow rate, G _Wt is the liquid fuel consumption.  2. A firing unit for burning a fuel mixture containing a liquid centrifugal nozzle integrated in a gas cylindrical manifold with gas supply openings, an air swirl and a vortex mixer, characterized in that the inner surface of the vortex mixer, directly behind the air swirl, is made confuser, turning into a cylindrical the neck and the axis of the gas supply openings in the gas manifold are oriented to the confuser generatrix, and the geometric characteristic of the liquid centrifugal nozzle and its position They are designed so that the fuel spray plume intersects in the initial flow section with the cylindrical neck of the vortex mixer.

Images