Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
  • F23D11/36—Details, e.g. burner cooling means, noise reduction means
  • F23D11/38—Nozzles; Cleaning devices therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
  • F23D11/36—Details, e.g. burner cooling means, noise reduction means
  • F23D11/38—Nozzles; Cleaning devices therefor
  • F23D11/383—Nozzles; Cleaning devices therefor with swirl means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
  • F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
  • F23R3/28—Continuous combustion chambers using liquid or gaseous fuel characterised by the fuel supply
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
  • F23C2900/07021—Details of lances
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/11002—Liquid fuel burners with more than one nozzle

Definitions

• the present invention relates to a dual-nozzle lance injector for injecting fuel oil into a gas turbine combustion chamber, to a gas turbine plant and to a method of supplying a gas turbine.
• gas turbines especially if used in plants for the production of electricity, may be supplied with different types of fuel.
• gas turbines especially gaseous fuels of different nature and characteristics (natural gas, syngas) or with fuel oils such as diesel fuel.
• gas turbines are provided with burner assemblies which include injectors, normally of the lance type, specifically designed to supply a controlled flow of diffusion fuel oil.
• Lance injectors generally comprise a plurality of coaxial tubular bodies, at one end of which a terminal provided with a nozzle is fitted.
• the tubular bodies define therebetween at least one delivery line between an inlet and the nozzle, and a return line, which allows the recovery of the excess fuel supplied to the nozzle.
• a line for supplying water may also be provided .
• the delivery line receives a flow of fuel oil at a pressure much higher than the combustion chamber and the injection flow is imposed by regulating a control valve of the return line.
• the control valve When the control valve is fully closed, the flow rate injected into the combustion chamber is maximum. Conversely, when the control valve is completely open there is maximum recovery of fuel through the return line and the flow rate injected into the combustion chamber is minimal.
• the structure of the power supply system of the fuel oil in known plants is complex, requires a large number of components and has a negative impact on times and costs both in design and in the construction and maintenance .
• the object of the present invention therefore is to provide a lance injector for injecting fuel oil into a gas turbine combustion chamber, a gas turbine plant and a method of supplying a gas turbine which allow overcoming or at least limiting the above drawbacks.
• a lance injector for injecting fuel oil into a gas turbine combustion chamber, a gas turbine plant and a method of supplying a gas turbine combustion chamber as defined in claims 1, 10 and 18, respectively.
• FIG. 1 shows a simplified block diagram of a plant for the production of electricity
• FIG. 2 shows a lateral sectional view according to an axial longitudinal plane, with parts removed for clarity, of a burner of a gas turbine incorporating a lance injector according to an embodiment of the present invention, incorporated in the plant in figure 1 ;
• figure 3 shows an enlarged detail of the lance injector in figure 1 ;
• figure 4 shows a more detailed block diagram of a part of the plant in figure 1 ;
• FIG. 5 shows a more detailed block diagram of a part of the plant in figure 1, according to a different embodiment of the present invention.
• figure 6 shows a graph showing quantities related to the plant in figure 1.
• reference numeral 1 indicates as a whole a gas turbine plant 1, in particular a plant for the production of electricity.
• Plant 1 is selectively connectable to a known distribution network 2 and includes a gas turbine assembly 3 and a control device 5.
• Plant 1 further comprises an alternator 4 of known type, which is mechanically connected to a shaft 7 of the gas turbine assembly 3 and actuated thereby.
• the control device 5 uses measured plant quantities (here not shown in detail) and set reference values to generate control signals, in order to control the operation of plant 1.
• the gas turbine assembly 3 comprises a compressor 8, a combustion chamber 9 and a gas turbine 10.
• Compressor 8 is of the multistage axial type and is provided with an inlet adjustable vane stage or IGV (Inlet Guide Vane) stage 11, driven by an IGV actuator 12 and respective control signals (not shown) provided by the control device 5.
• IGV Inlet Guide Vane
• the combustion chamber 9 receives the fuel from a supply system 15, which is controlled by the control device 5, as explained in more detail hereafter.
• the combustion chamber 9 comprises a plurality of burner assemblies 20, one of which is shown in figure 2, meaning that the others have an identical structure.
• the burner assembly 20 extends along a main axis A and comprises a peripheral main burner 21, a central pilot burner 22 and a lance injector 23 for injecting fuel oil into the combustion chamber 9.
• the main burner 21 is of the premixing type, is arranged around the pilot burner 22 and is provided with a diagonal swirler 25, which comprises a plurality of vanes 26, defining therebetween respective flow channels for conveying, with an oblique pattern with respect to the main axis A, a flow of combustion air and fuel gas towards the combustion chamber 9.
• the fuel is supplied through nozzles 27 placed on vanes 26.
• the pilot burner 22 is arranged coaxial to the main burner 21 and is provided with an axial swirler 30, which comprises a plurality of vanes 31, defining therebetween respective flow channels for conveying, substantially along the main axis A, a further flow of combustion air towards the combustion chamber 9.
• the lance injector 23 extends along the main axis A and has one end inserted inside the pilot burner 22.
• the lance injector 23 comprises a tubular casing 33, a first inner supply conduit 35, a second inner supply conduit 36 and a terminal element 38 provided with a first nozzle 40 and a second nozzle 41 for the first inner supply conduit 35 and the second inner supply conduit 36, respectively. Moreover, the lance injector 23 is provided with a mounting flange 42.
• the tubular housing 33 extends from the mounting flange 42 along the main axis A of the injector and therein houses both the first inner supply conduit 35 and the second inner supply conduit 36.
• the first inner supply conduit 35 and the second inner supply conduit 36 in turn extend along the main axis A, about which they are twisted.
• the first inner supply conduit 35 and the second inner supply conduit 36 extend along respective coiled paths having the main axis A as coil axis and have equal length and equal flow cross-section.
• a supply end 35a of the first inner supply conduit 35 is coupled to a first supply inlet 44 formed in the mounting flange 42, while an injection end 35b is coupled to the first nozzle 40.
• a supply end 36a of the second inner supply conduit 36 is coupled to a second supply inlet 45 formed in the mounting flange 42, while an injection end 36b is coupled to the second nozzle 41.
• the second supply inlet 45 is accessible from the outside independently of the first supply inlet 44.
• the two inner supply conduits 35, 36 and the relative nozzles 40, 41 can thus be supplied independently, since there are no reciprocal fluid couplings inside the lance injector 23.
• the terminal element 38 in which the first nozzle 40 and second nozzle 41 are formed, is fitted on the injection ends 35b, 36b of the first inner supply conduit 35 and the second inner supply conduit 36 and is attached to one end of the terminal casing by a fixing bush 47.
• the fixing is obtained by a threaded coupling or by hot fitting on the side of the tubular casing 33 and through opposed circumferential projections 48, 49 on the side of the terminal element 33.
• a guide bush 50 inserted by a stretch inside the tubular casing 33 and welded therein, is accommodated into respective seats and holds in place the injection ends 35b, 36b of the first inner supply conduit 35 and the second inner supply conduit 36.
• the guide bush 50 acts as a spacer element between the end of the tubular casing 33 and the terminal element 38. The latter is retained in abutment against the guide bush 50 by the fixing bush 47.
• the injection ends 35b, 36b of the first inner supply conduit 35 and the second inner supply conduit 36 communicate with the first nozzle 40 and the second nozzle 41, respectively, through a first outlet passage 51 and a second outlet passage 52 substantially straight, extending parallel inside the terminal element 38 and arranged symmetrically with respect to the main axis A.
• the first nozzle 40 and the second nozzle 41 are identical and arranged symmetrically with respect to the main axis A and, moreover, they have respective injection axes Bi, B 2 parallel to the main axis A.
• a first swirler 51a and a second swirler 52a are arranged inside the first outlet passage 51 and the second outlet passage 52, respectively.
• the first swirler 51a and the second swirler 52a are configured so as to generate a strong turbulence and rotate in-transit flows about the injection axes Bi, B 2 of nozzles 40, 41.
• FIG. 4 schematically shows the supply system 15, some of the burner assemblies 20 and the control device 5. Moreover, there is shown a water supply line 53 with a respective supply pump 54, used in certain operating conditions for flushing or cooling.
• the supply system 15 comprises a premix supply line 55 and a diffusion supply line 56, both connected to a fuel pump assembly 57 to receive respective flow rates of fuel oil .
• the premix supply line 55 is further connected to the premixing portion of the burner assembly 20, i.e. to the main burner 21 and the pilot burner 22 through a premix manifold 58 and premix fittings 59.
• a stop valve 60 and a premix control valve 61 allow adjusting a fuel flow rate Q F p to the main burner 21 and the pilot burner 22.
• the stop valve 60 and the premix control valve 61 are provided with respective actuators 60a, 61a, which are controlled by the control device 5 through a premix stop signal S S p and a premix control signal S RP , respectively.
• the premix supply line 55 is shown here as a single line. It is however understood that independent control lines and/or members may be provided for the main burner 21 and the pilot burner 22.
• the premix portion of the burner assembly 20 receives fuel gas instead of fuel oil and is thus supplied by separate and independent lines with respect to the diffusion supply line 56.
• the diffusion supply line 56 has a first branch 56a, which supply the first nozzles 40 through a first diffusion manifold 63, respective first diffusion fittings 64 and the respective first inner supply conduits 35, and a second branch 56b, which supplies the second nozzle 41 through a second diffusion manifold 65, respective second diffusion fittings 66 and the respective second inner supply conduits 36.
• the adjustment of the first flow rate of fuel oil QFDI to the first nozzle 40 is independent of the adjustment of the second flow rate of fuel oil QFD2 ⁇
• the stop valve 68 and the first diffusion control valve 69 are arranged along the diffusion supply line 56 upstream of the bifurcation between the first branch 56a and the second branch 56b, while the second diffusion control valve 70 is arranged along the second branch 56b.
• the first diffusion control valve 69 is arranged along the first branch 56a and the second diffusion control valve 70 is arranged along the second branch 56b.
• the stop valve 68, the first diffusion control valve 69 and the second diffusion control valve 70 are provided with respective actuators 68a, 69a, 70a, which are controlled by the control device 5 through a diffusion stop signal S SO , a first diffusion control signal S RD i and a second diffusion control signal S RD 2, respectively.
• control device 5 is configured for continuously supplying the first nozzle 40 of the lance injectors 23 during the whole operating period of the gas turbine 10 and for supplying the second nozzles 41 selectively in a condition of intermediate load between a low load condition, for example upon startup or in premixed operation, and a high load condition, in which the gas turbine 10 substantially delivers the nominal power.
• the intermediate load condition corresponds for example to a load range between 30% and 55% of the maximum load that can be delivered by the gas turbine 10.
• the graphs in figure 6 show the flow rates of fuel supplied to the lance injectors 23 according to the load.
• the upper portion of figure 6 shows the overall fuel flow rate QFDI+QFD2 ; the lower portion separately shows the first flow rate of fuel oil Q F DI supplied to the first nozzles 40 and the second flow rate of fuel oil Q F D2 supplied to the second nozzles 41.
• the control device 5 stops supplying fuel oil to the second nozzles 41 under low load conditions and high load conditions, when the system is in premix operation.
• the injection conditions are always optimal for both the first nozzles 40 and for the second nozzles 41, when they are used, and the required flow rates can be correctly atomized even in the absence of a return line or atomization air.
• the lance injectors 23 always work in an effective manner, while allowing obtaining an overall range of flows wide enough to meet all load conditions.
• the plant is simplified thanks to the structure of the lance injectors 23, since there is no need to provide a dedicated manifold and fittings.
• the water supply line 53 is connected to the second branch 56a of the diffusion supply line 56, for example to the second diffusion manifold 65.
• a stop valve 71 and a water control valve 72 arranged along the water supply line and provided with respective actuators 71a, 72a, are used to supply a water flow to the second nozzles 41 of the burners.
• Actuators 71a, 72a are controlled by the control device 5 through a water stop signal S S w and a water control signal S RW .
• the water flow is supplied when the supply of fuel oil to the second nozzles 41 is deactivated, i.e. in the low load condition or in the high load condition.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Nozzles For Spraying Of Liquid Fuel (AREA)
• Engine Equipment That Uses Special Cycles (AREA)
• Pressure-Spray And Ultrasonic-Wave- Spray Burners (AREA)
• Spray Control Apparatus (AREA)

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Publications (1)

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Cited By (1)

Citations (4)

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• 2013
  • 2013-10-31 IT IT001816A patent/ITMI20131816A1/it unknown
• 2014
  • 2014-10-31 EP EP14809708.2A patent/EP3063472B1/en active Active
  • 2014-10-31 CN CN201480060116.2A patent/CN105829801B/zh active Active
  • 2014-10-31 WO PCT/IB2014/065743 patent/WO2015063733A1/en active Application Filing
  • 2014-10-31 RU RU2016120851A patent/RU2672009C2/ru active

Patent Citations (4)

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