Nozzle structure of combustion chamber in low heat value of gas turbine and combustion method
Technical field
The present invention relates to the gas turbine technology field, is a kind of nozzle structure of combustion chamber in low heat value of gas turbine and combustion method.
Background technology
Enter 21 century, rational energy is effectively utilized and two indexs of environmental protective measure all must meet the requirements.Chinese large-sized iron and steel enterprise high energy consumption is the problem that we pay close attention to always, and during the 11th Five-Year, country has proposed employing blast furnace gas and oven gas and mixed from the purpose of low burnup iron and steel production, carries out the measure of gas turbine power generation.In addition this novel energy of living beings because have continuous recyclability, to the friendly of environment with can suppress the unusual effect of global climate, become the fourth-largest energy that is only second to coal, oil, natural gas, account for 3% of global total energy consumption.Therefore, promote the biomass fermentation power technology has particular importance to China meaning.But the calorific value of blast furnace gas and air gasification biogas all is lower than 1000Kcal/Nm
3, so the core difficult point of blast furnace gas turbine and the design of low heat value biomass gas gas turbine is the designing technique of low-calorific-value gas turbine combustion chamber.
The gas turbine combustion calorific value is lower than 1000Kcal/Nm
3Fuel gas mainly face combustion stability and residual two problems of CO.When gas turbine was operated in underload, the equivalent proportion in primary zone was lower, and flame is put out easily, needed to set up local diffusion swirl flame and came smooth combustion; When gas turbine was operated in high load capacity, because the increase of fuel quantity, the burn rate of CO was lower in the low calorie fuels, and it is residual easily to produce unburnt CO, reduced efficiency of combustion, increased the CO discharging, therefore needed to strengthen primary zone fuel and air blending process.At two problems that above low calorie fuels gas firing faces, general solution for the method that adopts complete diffusion flame and strengthen eddy flow under low load condition the retention flame, strengthen blending at high load capacity.But strengthen the increase that eddy flow can bring the combustion chamber flow resistance loss.
Summary of the invention
Nozzle structure of combustion chamber in low heat value of gas turbine of the present invention and combustion method, its objective is defective at prior art, proposed a kind of new solution: adopt diffusion flame with the partly-premixed method that combines, the two large problems that faces when solving the low calorie fuels gas firing: combustion stability and CO are residual.
For achieving the above object, technical solution of the present invention provides a kind of combustion method of combustion chamber in low heat value of gas turbine nozzle, it adopts diffusion flame with the partly-premixed combustion method that combines, combustion stability when solving the low calorie fuels gas firing and carbon monoxide residue problem; Step is:
Compressed air enters the circular passage from the rear portion, combustion chamber, and the various air admission holes by the burner inner liner wall enter burner inner liner successively, and remaining air is formed primary air, enters swirler passages by the air cyclone on the combustion chamber burner of burner inner liner head;
First row's fuel jet is directly injected swirler passages by first row's fuel swirl jet orifice, forms rich premix gas with the primary air in the swirler passages;
Second row's fuel swirl jet orifice is positioned at the swirler passages outlet, and its jet path is directly injected the combustion chamber;
When gas turbine was operated in underload, second row's fuel jet formed pure diffusion flame, as the stable ignition point, keeps flameholding;
When gas turbine is operated in high load capacity, first row's fuel jet promptly forms blending with an air in swirler passages, and second row's fuel jet is positioned at the swirler passages outlet, also can finish blending rapidly, strengthen the blending process in primary zone, guaranteed the carbon monoxide after-flame.
The combustion chamber burner that described combustion method uses comprises air cyclone, swirl jet hole, fuel nozzle; Its air cyclone comprises ring, cyclone outer shroud and swirl jet hole in the cyclone;
The cyclone inner and outer rings is totally one central axis, the umbrella portion of ring in the cyclone of mushroom hollow, insert in the axial region cavity of cylindric air cyclone outer shroud, the top of ring is concordant with the upper end of cyclone outer shroud in the cyclone, umbrella portion periphery is fixed in the inwall of cyclone outer shroud, and the top end face of ring and the space between the cyclone outer shroud inwall constitute swirler passages in the cyclone;
On the cylindrical cyclone outer shroud side wall upper part Zhou Yuan, be provided with the equally distributed majority of a ring-type air swirl jet orifice; The top axis of ring is provided with a fuel port in the cyclone of mushroom hollow, in its top umbrella portion, be provided with two row's fuel jet holes: first row's most fuel swirl jet orifices are positioned at the swirler passages bottom, ring-type evenly distributes, near the outlet of air swirl jet orifice, be eddy flow in the same way with the air swirl jet orifice, corresponding one by one; Second row's most fuel swirl jet orifices are positioned at the swirler passages outlet, and ring-type is evenly distributed on the interior Zhou Yuan of swirler passages outlet, enclose in fuel port Zhou Yuan, also are eddy flow in the same way with the air swirl jet orifice;
Fuel nozzle is inserted in the axial region cavity of ring in the air cyclone, and sealed sliding is joined, and the spout of fuel nozzle is positioned on the common axis of cyclone inner and outer rings over against fuel port.
Described combustion chamber burner, its described majority air swirl jet orifice is at least the through hole of 24 Φ 12, and air swirl jet orifice axis and axial angle are 29 °.
Described combustion chamber burner, most fuel swirl jet orifices of its described first row are at least the through hole of 24 Φ 10; Second row's most fuel swirl jet orifices are at least the through hole of 12 Φ 10.
The umbrella portion of ring is fixed in the inwall of cyclone outer shroud in the described combustion chamber burner, its described cyclone, is the below that is fixed in the air swirl jet orifice outlet of cyclone outer shroud side wall upper part.
Described combustion chamber burner, it comprises that also a flange-like master installs the limit, and it is the cyclone inner and outer ring, and the connector between fuel nozzle and the nozzle body is made of the linkage section and the flanged plate of cartridge type; The barrel dliameter of the cartridge type linkage section on main installation limit and the external diameter of cyclone outer shroud are suitable, the lower end is provided with circular bottom plate, the base plate diameter is greater than the barrel dliameter of cartridge type linkage section, the part that base plate stretches out cartridge type linkage section barrel dliameter is provided with through hole, through hole and bolt are suitable, by being bolted on the flanged plate, contact-making surface is with gasket seal; Flanged plate is positioned at the part center of cartridge type linkage section barrel dliameter, be respectively equipped with cyclone in the suitable protruding joint chair in rear end and fuel nozzle rear end that encircles, with the suitable protruding joint chair inwall in fuel nozzle rear end on be provided with screw thread, on the joint chair center flange plate through hole is arranged; With cyclone in the lateral seal groove is arranged on the suitable protruding joint chair in the rear end encircled, on the flanged plate between cartridge type linkage section tube inwall and the protruding joint chair through hole is arranged.
Described combustion chamber burner, the bottom edge of its described cyclone outer shroud are fixed in the main upper end that the cartridge type linkage section on limit is installed, in the cyclone on the flanged plate on the side, bottom of ring and main installation limit the respective inner walls of protruding joint chair be connected with expansion ring seale; The cavity that ring 13 lower, outer perimeter circles surround in cyclone outer shroud axial region cavity inner wall and the cyclone communicates by through hole on the flanged plate and fuel supply pipe road.Fuel nozzle is connected with thread seal with the main joint chair of installing on the axis of limit, and the fuel nozzle rear portion communicates with the fuel oil supply line.
Described combustion chamber burner, its described combustion chamber is the reverse-flow type multcan, and a combustion chamber burner is arranged in each tubular combustor.
Description of drawings
Fig. 1 is that the present invention adopts diffusion flame with partly-premixed low heat value of gas turbine structure of nozzle that combines and combustion method schematic diagram;
Fig. 2 is a blast furnace gas of the present invention combustion chamber overall structure schematic diagram;
Fig. 3 is a blast furnace gas combustion chamber burner perspective view of the present invention;
Fig. 4 is a blast furnace gas combustion chamber burner internal structure schematic diagram of the present invention;
Fig. 5 is a blast furnace gas combustion chamber burner process structure schematic diagram of the present invention
Fig. 6 is axial velocity profile figure on the longitudinal section, combustion chamber of the present invention;
Fig. 7 is head of combustion chamber CO of the present invention
2The mass fraction distribution map;
Fig. 8 is a head of combustion chamber radial velocity distribution map of the present invention;
Fig. 9 is a burner inner liner top wall surface temperature distribution map of the present invention;
Figure 10 is changeover portion of the present invention longitudinal section and out temperature distribution map.
The specific embodiment
Fig. 1 is to be that the present invention adopts diffusion flame with partly-premixed low heat value designs of nozzles method and the architectural feature that combines.This novel nozzle 9 adopts radial air cyclone 1, fuel jet is divided into two rows, first row's fuel jet 2 is directly injected swirler passages 4 by first row's fuel swirl jet orifice 3, form rich premix gas with the primary air in the swirler passages 45, second row's fuel swirl jet orifice 6 is positioned at swirler passages 4 outlets, and its jet path is directly injected the combustion chamber.When gas turbine was operated in underload, second row's fuel jet 7 formed pure diffusion flame, keeps flameholding as stable ignition point.When gas turbine is operated in high load capacity, first row's fuel jet 2 promptly forms blending with an air 5 swirler passages 4 in, and second row's fuel jet 7 is positioned at swirler passages 4 and exports, and also can finish blending rapidly, strengthen the blending process in primary zone 8, guaranteed the CO after-flame.
The blast furnace gas combustion chamber burner of using the inventive method design is the combustion chamber critical piece, is positioned at the head of combustion chamber.Fig. 2 is a combustion chamber overall structure schematic diagram, this combustion chamber is the reverse-flow type multcan, a combustion chamber burner 9 is arranged in each tubular combustor, cylindrical shape burner inner liner 23, the water conservancy diversion lining 27 of burner inner liner 23 and outside forms the circular passage, compressed air enters the circular passage from the rear portion, combustion chamber, various air admission holes by burner inner liner 23 walls (comprise cooling hole 28 successively then, blending hole 26 and primary holes 25 etc.) enter burner inner liner 23, remaining air is formed primary air 5, enters the combustion chamber by the air cyclone 1 on the combustion chamber burner 9 of burner inner liner 23 heads at last.Connect changeover portion 24 behind burner inner liner 23,23 outlets of circular burner inner liner are changed into fan-shaped, the back connects combustion gas turbine again.
As shown in Figure 3, be use the inventive method design blast furnace gas nozzle 9 stereochemical structures, constitute by air cyclone 1, swirler passages 4, fuel jet hole 3,6.Air cyclone 1 is a radial swirler, evenly is provided with the swirl jet hole 11 of 24 Φ 12 on its sidewall Zhou Yuan, and swirl jet hole 11 is 29 ° with axial angle.
Fig. 4 is a blast furnace gas combustion chamber burner internal structure schematic diagram of the present invention, can see among the figure, in the cyclone, outer shroud 13,17 totally one central axis, the top of ring 13 is provided with fuel port 14 in the cyclone of mushroom hollow, space in the cyclone between ring 13 and the cylindrical cyclone outer shroud 17 constitutes swirler passages 4, fuel jet hole 3,6 are positioned at the umbrella portion of cyclone ring 13, divide two rows to be provided with: first row's fuel swirl jet orifice 3 is positioned at swirler passages 4 bottoms, have first row's fuel swirl jet orifice 3 of 24 Φ 10, ring-type evenly distributes, near air swirl jet orifice 11 outlet, be eddy flow, correspondence one by one in the same way with air swirl jet orifice 11; Second row's fuel swirl jet orifice 6 is positioned at swirler passages 4 outlets, have second row's fuel swirl jet orifice 6 of 12 Φ 10, ring-type is evenly distributed on the interior Zhou Yuan of swirler passages 4 outlet, encloses in 14 week of fuel port circle, also is eddy flow in the same way with air swirl jet orifice 11.
When gas turbine was operated at full capacity, the swirl jet 2 of first row's fuel swirl jet orifice 3 formed rich premix gas with an air 5 premix in the passage 4 of air cyclone 1.When the gas turbine sub-load was worked, second row's fuel jet 7 that second row's fuel swirl jet orifice 6 produces became the point of safes burning things which may cause a fire disaster.
Fig. 5 is a blast furnace gas combustion chamber burner process structure schematic diagram of using method for designing of the present invention, and among the figure: combustion chamber burner 9 comprises main limit 16, interior 13 (having the fuel jet hole), cyclone outer shroud 17, fuel nozzle 18, the nozzle body 10 of encircling of cyclone installed.On the cylindrical cyclone outer shroud 17 side wall upper part Zhou Yuan, finish the air swirl jet orifice 11 of 24 Φ 12 by spark machined, each swirl jet hole 11 all is 29 ° with axial angle.Ring 13 also is cylindric in the cyclone of mushroom hollow, on its umbrella top, finish two row's fuel swirl jet orifices by spark machined: first row's fuel swirl jet orifice 3 of 24 Φ 10, be positioned at umbrella portion edge, second row's fuel swirl jet orifice 6 of 12 Φ 10, be positioned at umbrella portion top, on 14 weeks of fuel port are round; The trend of two row's fuel swirl jet orifices 3,6 is identical with air swirl jet orifice 11.
Umbrella portion with ring 13 in the air cyclone, insert in the axial region cavity of cylindric air cyclone outer shroud 17, the top of ring 13 is concordant with the upper end of cyclone outer shroud 17 in the cyclone, pass through Laser Welding, the umbrella portion edge of ring 13 in the cyclone is welded in the inwall of cyclone outer shroud 17,19 places, below of air swirl jet orifice 11 outlets make the interior ring 13 of cyclone affixed with cyclone outer shroud 17.Fuel nozzle 18 is inserted in the axial region cavity of ring 13 in the air cyclone, sealed sliding is joined, and the spout of fuel nozzle 18 is over against fuel port 14.
Flange-like master installs limit 16, and it is a cyclone inner and outer ring 13,17, and the connector between fuel nozzle 18 and the nozzle body 10 is made of the linkage section 29 and the flanged plate 30 of cartridge type; The barrel dliameter of the cartridge type linkage section 29 on main installation limit 16 and the external diameter of cyclone outer shroud 17 are suitable, the lower end is provided with circular bottom plate, the base plate diameter is greater than the barrel dliameter of cartridge type linkage section 29, the part that base plate stretches out cartridge type linkage section 29 barrel dliameters is provided with through hole, through hole and bolt 15 are suitable, be fixed on the flanged plate 30 by bolt 15, contact-making surface is with pad 20 sealings; Flanged plate 30 is positioned at the part center of cartridge type linkage section 29 barrel dliameters, be respectively equipped with cyclone in ring 13 the suitable protruding joint chair in rear end and fuel nozzle 18 rear ends, with the suitable protruding joint chair inwall in fuel nozzle 18 rear ends on be provided with screw thread, on the joint chair center flange plate through hole is arranged; With cyclone in the lateral seal groove is arranged on the suitable protruding joint chair in ring 13 rear end, on the flanged plate between 29 inwalls of cartridge type linkage section and the protruding joint chair through hole is arranged.
The bottom edge of cyclone outer shroud 17 is fixed in the upper end of the cartridge type linkage section 29 on main installation limit 16, and the respective inner walls of protruding joint chair is tightly connected with packing 21 on the flanged plate on the side, bottom of the interior ring 13 of cyclone and main installation limit 16; The cavity that ring 13 lower, outer perimeter circles surround in cyclone outer shroud 17 axial region cavity inner walls and the cyclone is not by through hole on the flanged plate 30 and fuel supply pipe road communicate (illustrating among the figure).Fuel nozzle 18 and the main joint chair of installing on 16 axis of limit are tightly connected with screw thread 22, fuel nozzle 18 rear portions communicate with the fuel oil supply line (not illustrating among the figure).
Use the blast furnace gas combustion chamber CFD analog result of the inventive method:
In order to check the effect of this new type nozzle, the operating mode when certain model gas-turbine combustion chamber has been adopted jet combustion low combustion value furnace gas of the present invention has been carried out numerical simulation.
Fig. 6 is the axial velocity profile figure on the longitudinal section, combustion chamber of the present invention, because the axial jet velocity of this nozzle is very big, therefore in the primary zone, combustion chamber, do not form the recirculating zone, center, but an annular low speed recirculating zone has appearred in the injection stream outside, high-temperature flue gas will reach the purpose of the retention flame from outer side reflux like this.
Fig. 7 is the CO of head of combustion chamber of the present invention
2The mass fraction distribution map.As shown in the figure, because jet expansion is the convergence form, so jet has radial velocity entad when just leaving nozzle, and because the axial velocity of injection stream is very big, the firm delivery nozzle of jet also can not expanded laterally; Along with the distance of leaving nozzle increases, jet is under action of centrifugal force, and radial velocity entad becomes centrifugal gradually, and its radial velocity reaches maximum (see figure 8) before primary holes, so jet begins to expand outwardly, forms recirculating zone, the outside.The high-temperature flue gas that burning produces and all be brought into recirculating zone, the outside from the air that primary holes enters flows to head of combustion chamber, both can play the effect of the retention flame, has strengthened the mixing of air and fuel again.Because the following current district of head of combustion chamber is positioned at the center, for the impulse ratio of primary holes jet a little less than, so very big (see figure 8) of the penetration depth of primary holes has further strengthened the blending of fuel and air.
Fig. 9 is that the burner inner liner top wall surface temperature of combustion chamber of the present invention distributes, because fuel and the key reaction district of air and the center (see figure 7) that high-temperature flue gas all is positioned at the combustion chamber, away from the burner inner liner wall, therefore the wall surface temperature of burner inner liner relatively evenly and peak less than 800K, also be lower than the maximum temperature that the burner inner liner material can bear, help prolonging the service life of burner inner liner.
Figure 10 is connected on the changeover portion longitudinal section behind the burner inner liner and imports and exports and go up Temperature Distribution, as shown in the figure, high-temperature flue gas is after the process changeover portion, temperature distributing disproportionation evenness reduces greatly, maximum temperature on the cross section drops to 1363K by the 619K of inlet, the Temperature Distribution coefficient drops to 0.086 from 0.256 of changeover portion inlet (being the burner inner liner outlet), satisfies the requirement that turbine distributes to inlet temperature.
In sum, gas-turbine combustion chamber adopts new type nozzle of the present invention to come the lower heat of combustion blast furnace gas, can guarantee the combustion stability under the underload, can strengthen fuel and Air mixing again, strengthens CO and O
2Reaction, reduce the discharging of CO, improve efficiency of combustion, can satisfy the designing requirement of combustion chamber.