Reheat burner injection system with fuel lances
View Patent ↗The disclosure relates to a burner such as for a secondary combustion chamber of a gas turbine with sequential combustion having a first and a second combustion chamber, with an injection device for introduction of at least one gaseous and/or liquid fuel into the burner. The injection device has at least one body which is arranged in the burner with at least one nozzle for introducing the at least one gaseous fuel into the burner, the at least one body being configured as a streamlined body which has a streamlined cross-sectional profile and which extends with a longitudinal direction perpendicularly or at an inclination to a main flow direction prevailing in the burner. At least one nozzle has its outlet orifice downstream of a trailing edge of the streamlined body.
1. Burner for a combustor of a turbine, comprising:
an injection device for introduction of at least one gaseous and/or liquid fuel into the burner, wherein the injection device has at least one body which is arranged in the burner with at least two nozzles at a trailing edge of the body for introducing the at least one fuel into the burner, the at least one body being configured as a streamlined body which has a streamlined cross-sectional profile and which extends with a longitudinal direction perpendicularly or at an inclination to a main flow direction prevailing in the burner, the at least one body including tubing for supplying the at least one gaseous and/or liquid fuel to the at least two nozzles and an interspace for delivery of carrier air to the at least two nozzles; and
two lateral surfaces of the body essentially parallel to the main flow direction, wherein the at least two nozzles have outlet orifices downstream of the trailing edge of the streamlined body for injecting the fuel and the carrier gas at an inclination angle of between 0-30° with respect to the main flow direction.
2. Burner according to claim 1 , wherein the distance (d) between the essentially straight trailing edge at the position of the nozzles, and the outlet orifices of said nozzles, measured along the main flow direction, is at least 2 mm.
3. Burner according to claim 1 , wherein the body comprises:
an enclosing outer wall defining said streamlined cross-sectional profile, wherein within this outer wall, there is provided a longitudinal inner fuel tubing for introduction of liquid and/or gaseous fuel, with branching off tubing leading to the at least two nozzles.
4. Burner according to claim 3 , wherein the longitudinal inner fuel tubing is circumferentially distanced from the outer wall defining the interspace for delivery of carrier air to the at least two nozzles.
5. Burner according to claim 3 , wherein transitions between the longitudinal inner fuel tubing and the branching off tubing, on the fuel side thereof, are provided with rounded edges.
6. Burner as claimed in claim 1 , wherein the streamlined body has a cross-sectional profile which is mirror symmetric with respect to a central plane of a body.
7. Burner according to claim 3 , wherein within said longitudinal inner fuel tubing there is provided a second inner fuel tubing for a second type of fuel, wherein this second type of fuel is a liquid fuel and wherein gaseous fuel is delivered by an interspace between walls of said longitudinal inner fuel tubing and walls of the second inner fuel tubing.
8. Burner as claimed in claim 1 , wherein upstream of the at least two nozzles on at least one of the at least two lateral surfaces there is located at least one vortex generator, wherein the vortex generator has an attack angle in a range of 15-20° and/or a sweep angle in a range of 55-65°, wherein the at least two nozzles are arranged at different positions along said trailing edge, wherein upstream of each of these at least two nozzles at least one vortex generator is located, and wherein vortex generators to adjacent nozzles are located at opposite lateral surfaces.
9. Burner according to claim 8 , wherein the at least one vortex generator is provided with cooling elements, wherein these cooling elements are effusion cooling holes provided in at least one surface of the vortex generator, and wherein the cooling holes are fed with air from the carrier gas feed used for fuel injection.
10. Burner according to claim 1 , wherein the streamlined body extends across an entire flow cross section between opposite walls of the burner, wherein the burner is an annular burner arranged circumferentially with respect to a turbine axis, and wherein between 10-100 streamlined bodies, are arranged around the circumference, all of them being equally distributed along the circumference.
11. Burner according to claim 1 , wherein the body is provided with cooling elements, wherein these cooling elements are for internal circulation of cooling medium along sidewalls of the body and/or cooling holes located near the trailing edge, and wherein the cooling elements are fed with air from the carrier gas feed also used for fuel injection.
12. Burner according to claim 1 , wherein upstream of the body and downstream of a last row of rotating blades of the turbine there are no additional vortex generators, and no additional flow conditioning elements arranged inside the walls of the burner.
13. Burner according to claim 1 , wherein the nozzles are configured to inject fuel together with a carrier air stream, and wherein the carrier air is low pressure air with a pressure in a range of 10-20 bar.
14. A burner according to claim 1 , in combination with a combustion chamber for the combustion of MBtu fuel with a calorific value of 5000-20,000 kJ/kg.
15. Burner according to claim 1 , wherein the distance (d) between the essentially straight trailing edge at the position of the nozzles, and the outlet orifices of said nozzles, measured along the main flow direction, is at least 3 mm.
16. Burner according to claim 1 , wherein the distance (d) between the essentially straight trailing edge at the position of the nozzles, and the outlet orifices of said nozzles, measured along the main flow direction, is at least 4-10 mm.
17. Burner according to claim 8 , wherein at least four nozzles are arranged along said trailing edge and vortex generators alternatingly are located at the two lateral surfaces, or wherein downstream of each vortex generator there are located the at least two nozzles.
18. Burner according to claim 1 , wherein the streamlined body extends across an entire flow cross section between opposite walls of the burner, wherein the burner is an annular burner arranged circumferentially with respect to a turbine axis, and wherein between 40-80 streamlined bodies, are arranged around the circumference, all of them being equally distributed along the circumference.
19. Burner according to claim 1 , wherein the nozzles are configured to inject fuel together with a carrier air stream, and wherein the carrier air is low pressure air with a pressure in a range of 16-20 bar.
20. A burner according to claim 1 , in combination with a combustion chamber for the combustion of MBtu fuel with a fuel comprising hydrogen gas.