In-stream burner module

Abstract

A burner module in an air stream has a feed pipe of substantially circular cross section and an axis, fuel injection orifices situated on the pipe and intended to produce a flame, oxidant injection orifices and fins arranged symmetrically with respect to a plane P of flow of the fuel upstream of the burner module and laterally on the pipe on each side of the fuel injection orifices. There are at least two fuel injection orifices in a section of the pipe and they have an axis that makes an angle with the plane of flow P of the oxidant. In this way, gas is injected at several orifices situated in at least two divergent planes. These two planes delimit a space to which fuel and to which oxidant are not supplied.

Claims

1. A burner module in an air stream comprising: a feed pipe of substantially circular cross section and having a central axis; a plane P passing through the center of the feed pipe and parallel to an air stream; at least two primary fuel injection orifices situated on a section of the pipe and intended to produce a flame, the at least two primary fuel injection orifices are arranged symmetrically with respect to the plane P, wherein each of the at least two primary fuel injection orifices is at an angle with the plane P, the angle is between 10 and 30 inclusive; a first fin comprising a first deflection element; a second fin comprising a second deflection element, wherein the first fin and the second fin are arranged symmetrically with respect to the plane P, wherein the first fin and the second fin are each at an angle with the plane, and the angle is between 2 and 3; wherein the first deflection element and the second deflection element are each at an angle with respect to the plane P, and the angle is substantially equal to the angle ; a third fin comprising a third deflection element; a fourth fin comprising a fourth deflection element, wherein the third fin and the fourth fin are arranged symmetrically with respect to the plane P, wherein the third fin and the fourth fin are each at the angle with the plane P; wherein the third deflection element and the fourth deflection element are each at the angle with respect to the plane P; a first oxidant injection opening and a second oxidant opening that are arranged symmetrically with respect to the plane P, wherein the first oxidant injection opening is defined between the first deflection element and the third deflection element, and the second oxidant injection opening is defined between the second deflection element and the fourth deflection element; wherein the third deflection element is positioned further downstream of the first oxidant injection opening relative to the air stream than the first deflection element; and wherein the fourth deflection element is positioned further downstream of the second oxidant injection opening relative to the air stream than the second deflection element.

2. The burner module according to claim 1, wherein the at least two primary fuel injection orifices have different sizes on each side of the plane P.

3. The burner module according to claim 1, wherein at least two secondary fuel injection orifices are each at an angle with the plane P and the angle is greater than the angle .

4. The burner module according to claim 3, wherein the at least two secondary fuel injection orifices have a total area representing 5% to 20% of the total area of the at least two primary fuel injection orifices.

5. The burner module according to claim 1, wherein the first oxidant injection opening and the second oxidant injection opening each have a total area between 3% and 15% inclusive of a total area of each of the first fin, the second fin, the third fin, and the fourth fin.

6. The burner module according to claim 1, wherein the first oxidant injection opening and the second oxidant injection opening have different sizes on each side of the plane P.

7. The burner module according to claim 1, further comprising: a fifth fin comprising a fifth deflection element, wherein a third oxidant injection opening is defined between the third deflection element and the fifth deflection element, wherein respective sizes of the first oxidant injection opening and the third oxidant injection opening increase with the distance from the at least two primary fuel injection orifices.

8. The burner module according to claim 1, further comprising a shield placed downstream of the pipe with respect to the air stream, the shield having holes situated in line with the at least two primary fuel injection orifices.

9. The burner module according to claim 8, wherein the holes are situated on a wall of the shield, wherein each portion of the wall that correspond to one of the holes makes an angle substantially equal to 90 relative to a second central axis of a corresponding one of the at least two primary fuel injection orifices.

10. The burner module according to claim 9, further comprising baffles situated in an exterior part of the burner module and having an interior rim with an angle equal to and opposite that of the first deflection element.

11. A combustion process comprising providing an oxidant that has an oxygen concentration less than 21% to the burner module according to claim 1.

12. A combustion method comprising premixing in a space between a feed pipe and a shield of the burner module according to claim 8.

13. A burner comprising a plurality of burner consisting modules according to claim 1.

14. A burner comprising a pair of adjacent burner modules according to claim 2, wherein for each of the pair of adjacent burner modules, one of the at least two primary fuel injection orifices on a first side of the corresponding plane P has a different size than another of the at least two primary fuel injection orifices on an opposite side of the plane P.

15. A burner comprising a pair of adjacent burner modules according to claim 6, wherein for each of the pair of adjacent burner modules, the first oxidant injection opening on a first side of the corresponding plane P has a different size than the second oxidant injection opening on an opposite side of the plane P.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view of a burner module in accordance with the invention showing the fuel flow,

(2) FIG. 2 is a view of the FIG. 1 burner module showing the oxidant flow,

(3) FIG. 3 is a detail of the pipe of the burner module,

(4) FIG. 4 is a variant of the pipe from FIG. 3,

(5) FIG. 5 is a view of one side of the fins,

(6) FIG. 6 is a view in section of an in-stream burner consisting of an assembly of burner modules,

(7) FIG. 7 is a rear view of FIG. 6,

(8) FIG. 8 shows a variant of an in-stream burner consisting of a plurality of modules seen from the front,

(9) FIG. 8a is a section of FIG. 8 on the plane AA,

(10) FIG. 8b is a section of FIG. 8 on the plane BB,

(11) FIG. 9a shows in section a variant of the FIG. 8 burner on the plane AA,

(12) FIG. 9b is a section of the same variant as FIG. 9a on BB.

DETAILED DESCRIPTION

(13) The assemblies of in-stream burners that can be seen in FIG. 7 consist of a plurality of in-stream burner modules I disposed side-by-side, each in-stream burner module comprises a pipe 2 constituting a fuel feed pipe. Each burner module I comprises fins 3 disposed on either side of the pipe 2 in which the fuel 4 flows symmetrically with respect to a plane P and at an angle . The fuel flows through injection orifices 20 symmetrically disposed on either side of the plane P.

(14) The pipe 2 is covered by a shield 5 pierced with holes 50 facing the orifices 20.

(15) The fins 3 on one side are at a greater or lesser distance from the pipe 2. The fin 30 is the closest, the fin 31 is at an intermediate location and the fin 32 is disposed farthest to the outside i.e. farthest from the pipe 2. The fins 30, 31, 32 are separated from one another by openings 33. It is of course possible to have more than or less than three fins.

(16) The operation of the burner module will now be explained.

(17) The fuel 4 arrives via the pipe 2, it is injected into the combustion chamber 6 via the orifices 20. These orifices 20 are oriented with an angle relative to the plane P of flow of the fuel. This angle makes it possible to delimit a space with no input of fuel and with no input of oxidant, which encourages internal recirculation of the combustion gases 4 inside the flame as shown in FIG. 1 by creating a principal vortex or turbulence 40 that brings toward the center a great part of the burnt gases. The angle of the fins is between substantially 2a and 3a inclusive.

(18) In the embodiment illustrated by FIGS. 8, 8a and 8b, the injection orifices 20 of the same module I have sections of different size and therefore different flow rates of fuel 4 on each side of the plane P, i.e. between the top and the bottom if P is horizontal. Thus by alternating modules I with the section size of the orifices 20 increased below the plane P and modules I with the section size of the orifices 20 increased above the plane P a component 41 radial to the main turbulence 40 is created. This radial component 41 reduces the flame lengths. The ratio of the sizes of the sections between the orifices 20 at the top and at the bottom can therefore vary between 0.25 and 4 and advantageously between 0.5 and 2.

(19) In an embodiment illustrated by FIGS. 9a and 9b, the TEG openings 33 of the same module I have sections of different size between the top and the bottom sides of the plane P. Thus by alternating modules I with openings 33 of increased size at the bottom and modules with openings 33 of increased size at the top the complementary component 41 radial to the turbulence 40 is created or increased, which decreases the flame lengths.

(20) FIG. 2 shows the circulation of the TEG 7 or turbine gases that enter via the openings 33 with an angle thanks to the deflection elements 34. This makes it possible to create a stabilization zone 70.

(21) As FIG. 5 illustrates, the baffles 8 have an end having a rim 80 that cooperate with the deflection element 34 of the fin 32 to enable a flow of the TEG 7 around the burner modules 1 parallel or nearly parallel to the plane P. The space between the deflection element 34 of the fin 32 and the rim 80 is larger than the openings 33. The rim 80 makes an angle .

(22) Between the pipe 2 and the shield 5 circulate TEG (cf. FIG. 3) that are aspirated via the orifice 20, the diameter of which is preferably larger than that of the holes 50, toward the combustion chamber 6 and therefore enables premixing of the fuel 4. The shield 5 has plane walls 52 that are more favorable to the creation of vortices. The holes 50 enables the injection of the gas with an angle relative to the wall 52 of the shield 5.

(23) In accordance with a variant FIG. 4 illustrates, the pipe 2 has secondary injection openings 21 that enable the injection of the fuel 4 with an angle greater than . Each secondary opening 21 is placed facing a secondary hole 51 of the shield 5. The quantity of fuel 4 injected is from 80% to 95% via the orifices 20 and the holes 50 and from 5% to 20% via the secondary orifices 21 and the secondary holes 51.