SHAPED BURNER PIECE WITH INTERNAL FLUE GAS RECIRCULATION

Description

Technical field

[0001] The invention relates to a burner shaped piece for monobloc burners for water heating and steam generation with low nitrogen oxide emissions.

State of the art

[0002] In large power plants such as power stations, refineries or chemical plants, power burners with burner shaped pieces are used. In field of water heating or steam generation, monobloc burners with compact design are commonly used, and no concrete elements are used. Currently, there is an effort to design burners with nitrogen oxide emissions as low as possible. Lessons learned from the design of shaped pieces for power burners could be used by design of a burner shaped piece suitable for reduction of NOx emissions with use of flue gas recirculation.

[0003] Document WO 01/63176 A1 introduces a burner assembly that is designed for installation into the wall or roof of a furnace. The front part of the burner assembly which projects into the combustion zone of the furnace consists of a cylindrical body of a larger diameter and a concentric smaller cylindrical body arranged therein, so that an annular channel between them for inlet of recirculated flue gas is formed. Outside the wall of the furnace the inlet of the air is arranged, which is mixed in the annular channel with the recirculated flue gas in the required ratio to reduce NOx emissions.

[0004] EP 1 867 923 A2 introduces a burner with low CO and NOx emissions, comprising a hollow cylindrical burner body in the centre of which primary gas is fed through a nozzle into the air stream and secondary gas is fed along the inner and outer perimeter of the body. The burner body has ports in the upper part around the perimeter, which have rounded upper surfaces to take advantage of the effect of the flowing viscous gas which flows along the rounded upper surfaces and this allows to introduce more gas to enter the gas/air mixture resulting in better flame stability and it solves the problems of flame pulsation.

[0005] Document EP 0 408 171A presents a burner assembly with two diffusers installed in the furnace wall. The fuel is fed into the inner combustion diffuser. This combustion diffuser has a shaped, elongated front portion around which a mixing diffuser is arranged, so that a channel is formed between the outer wall of the combustion diffuser and the inner wall of the mixing diffuser in order to enable the air to flow into the fuel to form a mixture.

[0006] The aim of the invention is to introduce a burner shaped piece with internal flue gas recirculation adapted to the compact dimensions of monobloc natural gas burners.

Summary of the invention

[0007] The above mentioned shortcomings are eliminated by a burner shaped piece with internal flue gas recirculation according to the invention, the substance of which is that it comprises an inlet gas-air diffuser and in front of it at an axial distance an outlet gas-air-flue diffuser is arranged, wherein the diffusers are connected together by four regularly spaced ribs arranged around an inner circumference of the burner shaped piece and the gas-air diffuser has a hollow conical taper terminated by a cylindrical flow-direction regulator, wherein the gas-air-flue diffuser has a hollow conical taper terminated by a cylindrical flow-direction regulator, wherein the gas-air-flue diffuser has a larger diameter as at the beginning and so at the end of its hollow conical taper than the diameter at the beginning and at the end of the hollow conical taper of the gas-air diffuser, and in the spaces between the outer surface of the gas-air diffuser and the inner face of the gas-air-flue diffuser and the inner surface of the hollow conical taper of the gas-air-flue diffuser, four evenly spaced flue gas channels are formed around the peripheral shell of the burner shaped piece with inlets for flue gas and on the outer circumference of the burner shaped piece groove-shaped channels are formed along its entire length and are recessed into each rib.

[0008] In a preferred embodiment the gas-air diffuser has a cylindrical surface on the outer circumference provided with a set-up opening adapted for adjusting a monobloc burner having an axis perpendicular to the axis of the gas-air diffuser.

Brief description of drawings

[0009] The invention will be further explained by use of drawings, in which Fig. 1 is a front view of an outlet of a burner shaped piece according to the invention, Fig. 2 is a section through the burner shaped piece along the Z-Z line of Fig. 1, Fig. 3 is a perspective view of an inlet of the burner shaped piece, Fig. 4 is a perspective view of an outlet of the burner shaped piece and Fig. 5 is a perspective view of the burner shaped piece from aside.

Description of preferred embodiments

[0010] 

Fig. 1 is a front view of the outlet of a rotationally symmetrical burner shaped piece 1 according to the invention. Only edges of the flow-direction regulators 6 and 7 of diffusers 2 and 3, respectively, and further, four circumferentially uniformly spaced channels 9 for the installation of the secondary gas nozzles can be seen.

Fig. 2 is an axial section of the burner shaped piece 1 along the Z-Z line of Fig. 1. It can be seen that it consists of a gas-air diffuser 2 at the inlet and a gas-air-flue diffuser 3 at the outlet. Diffusers 2 and 3 are arranged spaced apart from each other and are connected together by four ribs 8 regularly spaced along the inner circumference of the shaped piece 1. The gas-air diffuser 2 has a hollow conical taper 4 and a cylindrical surface 12 on its outer circumference. The conical taper 4 is terminated by a cylindrical flow-direction regulator 6. The diffuser 2 is provided with a set-up opening 10 on said cylindrical surface 12 for adjusting an monobloc burner (not shown). This opening 10 has an axis perpendicular to the axis of the diffuser 2. The gas-air-flue diffuser 3 has a hollow conical taper 5 terminating in a cylindrical flow-direction regulator 7. The gas-air-flue diffuser 3 has a larger diameter as at the beginning and so at the end of its taper 5 than the diameter at the beginning and at the end of the taper 4 of the gas-air diffuser 2, because a larger amount of the mixture of fuel-air and flue gas B flows through it, than it is the case of the gas-air diffuser 2, where only fuel-air mixture A flows. In the spaces between the outer surface of the diffuser 2 and the inner face 13 of the diffuser 3 and the inner surface of the taper 5, four evenly spaced flue gas channels 11 with four inlets for flue gas B are formed around the peripheral shell of the burner shaped piece 1
The gas-air mixture A is accelerated in the gas-air diffuser 2 and a vacuum is created, thereby ensuring the suction of the flue gas B through the flue gas channel 11, as shown by the arrow, where the flue gas B arrives at the periphery of the burner shaped piece 1 directly from the combustion chamber.
On the outer circumference of the burner shaped piece 1, groove-shaped channels 9 are formed along its entire length and are recessed into each rib 8. Into these channels 9 secondary nozzles (not shown) of the gas burner are installed. The ribs 8 are important for reinforcement of the entire burner shaped piece 1 and their thickness is also one of the factors which affects the amount of flue gas B sucked through the channel 11.

Fig. 3 is a perspective view of the inlet of burner shaped piece 1and ilustrates the inlets of flue gas channels 11 for flue gas B. The symmetrically arranged channels 9 for the installation of the secondary nozzles can also be seen here, and the inner surface of the flow-direction regulator 6 of the gas diffuser 2 can be seen inside the burner shaped piece 1.

Fig. 4 is a perspective view of the outlet of burner shaped piece 1. The inner surface of the flow-direction regulator 7 of the gas-flue diffuser 3 and the inlets of the flue gas channels 11 can be seen.

Fig. 5 is a perspective view of the burner shaped piece 1 from aside. The flue channel 11 and the shape of the ribs 8 are ilustrated.

List of reference signs

[0011] 

A

- gas-air mixture

B

- flue gas

1

- burner shaped piece

2

- gas-air diffuser

3

- gas-air-flue diffuser

4

- taper of the gas-air diffuser

5

- taper of the gas-air flue diffuser

6

- gas-air diffuser flow-direction regulator

7

- flow-direction regulator for gas-air-flue diffuser

8

- ribs

9

- channel for installation of secondary nozzle

10

- set-up opening

11

- flue gas channel

12

- cylindrical surface of the gas diffuser

13

- inner face of the gas-air-diffuser

Claims

1. Burner shaped piece (1) with cylindrical shape, which comprises an inlet gas-air diffuser (2) and in front of it at an axial distance an outlet gas-air-flue diffuser (3) is arranged, wherein the diffusers (2, 3) are connected together by four regularly spaced ribs (8) arranged around an inner circumference of the burner shaped piece (1) and the gas-air diffuser (2) has a hollow conical taper (4) terminated by a cylindrical flow-direction regulator (6), wherein the gas-air-flue diffuser (3) has a hollow conical taper (5) terminated by a cylindrical flow-direction regulator (7), wherein the gas-air-flue diffuser (3) has a larger diameter as at the beginning and so at the end of its hollow conical taper (5) than the diameter at the beginning and at the end of the hollow conical taper (4) of the gas-air diffuser (2), and in the spaces between the outer surface of the gas-air diffuser (2) and the inner face (13) of the gas-air-flue diffuser (3) and the inner surface of the hollow conical taper (5) of the gas-air-flue diffuser (3), four evenly spaced flue gas channels (11) are formed around the peripheral shell of the burner shaped piece (1) with inlets for flue gas (B) and on the outer circumference of the burner shaped piece (1) groove-shaped channels (9) are formed along its entire length and are recessed into each rib (8).

2. Burner shaped piece (1) according to claim 1, wherein the gas-air diffuser (2) has a cylindrical surface (12) on the outer circumference provided with a set-up opening (10) adapted for adjusting a monobloc burner having an axis perpendicular to the axis of the gas-air diffuser (2).

Ansprüche

1. Brennerformstück mit einer zylinrischen Form, der ein Einlauf-Gas-Luft Difuzor (2) beinhaltet und vor dem in einem axialen Abstand ein Auslauf-Gas-Luft Difuzor (3) angeordnet ist, wobei die Dufusers (2, 3) miteinander mit vier auf dem Innerumfang des Brennerformstücks (1) regelmässig angeordneten Rippen (8) verbunden sind und der Einlauf-Gas-Luft Difuzor (2) hat eine hohle Kegelverengung (4) die mit einem zylindrischen Umlenkstück (6) versehen ist und der Abstand Auslauf-Gas-Luft Difusor (3) hat eine hohle Kegelverengung (4) die mit einem zylindrischen Umlenkstück (7) beendet ist, wobei der Auslauf-Gas-Luft Difusor (3) einen grosseren Durchmesser auf dem Anfang als auch auf der Ende der Verengung (5) als der Durchmesser auf dem Anfang als auch auf der Ende der Verengung (4) des Einlauf-Gas-Luft Difuzor (2) ist, hat und in den Zwischenräumen zwischen den Aussenfläche des Einlauf-Gas-Luft Difuzor (2) und zwischen der Aussenfläche des Einlauf-Gas-Luft Difuzors (2) und einem Innerstirn (13) des Auslauf-Gas-Luft Difuzors (3) und der Innerfläche der Verengung (5) des Auslauf-Gas-Luft Difuzors (3) auf dem Umfangmantel des Brennerformstücks (1) vier regelmässig angerdneten Abgaskanäle (11) mit Entritt für Abgas (B) versehen sind und auf dem Aussenumfang des Brennerformstücks (1) auf derer ganzen Länge die Kanäle (9) in der Form einer Nut versehen sind, die in jede Rippe (8) eingesenkt sind.

2. Brennerformstück nach dem Anspruch 1, wo der Einlauf-Gas-Luft Difuzor (2) auf dem Aussenumfang eine zylindrische Fläche (12) hat, die mit einer Ausrichtungsöffnung (10) für das Ausrichten eines nicht dargestellten Monoblockbrenners, der eine senkrechte Achse zur Achse des Difusors (2) hat, versehen ist.

Revendications

1. Pièce de brûleur façonné de forme cylindrique, composé d'un diffuseur de gaz-air d'entrée (2) et d'un diffuseur de fumée gaz-air de sortie (3) espacés à une distance axiale, dans lequel les diffuseurs (2, 3) sont reliés entre eux par quatre nervures (8) régulièrement positionnées le long de l'intérieur de la circonférence du pièce de brûleur (1) et le diffuseur de gaz-air (2) possède un cône creux (4) terminé par un redresseur cylindrique (6) et le diffuseur de fumée gaz-air (3) comporte un cône creux terminé par un redresseur cylindrique (7), dans lequel le diffuseur de fumée gaz-air (3) a un diamètre plus grand au début ainsi qu'à l'extrémité du cône (5) que le diamètre au début et à l'extrémité du cône (4) du diffuseur de gaz-air (2) et dans les espaces entre la surface extérieure du diffuseur de gaz-air (2) et la face intérieure (13) du diffuseur de fumée gaz-air (3) et la face intérieure du cône (5) diffuseur de fumée gaz-air (3), quatre canaux de fumée (11) régulièrement positionnés avec entrées de fumée (B) sont créés sur la face périphérique du pièce de brûleur (1) et des canaux (9) en forme rainure sont créés le long de la circonférence extérieure du pièce de brûleur (1), qui sont encastrés dans chaque nervure (8).

2. Pièce de brûleur selon la revendication 1, dans lequel le diffuseur de gaz-air (2) contient une surface cylindrique (12) sur sa circonférence extérieure équipée d'une ouverture (10) pour la mise en place d'un brûleur monobloc, qui n'a pas été représenté, ayant un axe perpendiculaire à l'axe du diffuseur (2).

Drawing