AU2005206625A1

AU2005206625A1 - Flexible nozzle mixing burner comprising a swirl chamber

Info

Publication number: AU2005206625A1
Application number: AU2005206625A
Authority: AU
Inventors: Volker Hackh; Andreas Kulkies
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2004-01-22
Filing date: 2005-01-14
Publication date: 2005-08-04
Also published as: DE102004003343A1; JP2007518959A; EP1706669B1; NO20063738L; EP1706669A2; WO2005071314A3; US20070287108A1; ZA200604745B; ES2349012T3; DE502005009897D1; EA008661B1; WO2005071314A2; BRPI0507029A; CA2554034A1; PL1706669T3; ATE474190T1; NO330418B1; EA200601111A1; KR20060132676A

Abstract

An apparatus and method for a burner is disclosed. In an embodiment of an apparatus of the present invention, the burner includes a combustion gas tube with a first gas inlet line coupled to the combustion gas tube and an oxygen-containing gas tube with a second gas inlet line coupled to the oxygen-containing gas tube. A swirl chamber is disposed between either the first gas inlet line and the combustion gas tube or between the second gas inlet line and the oxygen-containing gas tube. In accordance with an embodiment of a method of the present invention, the method includes controlling a flow of a combustion gas to the combustion gas tube and controlling a flow of an oxygen-containing gas to the oxygen-containing gas tube. The combustion gas or the oxygen-containing gas is swirled in a swirl chamber and the combustion gas and the oxygen-containing gas is supplied to a burner.

Description

CERTIFICATION OF VERIFICATION 1. Derek Ernest LIGHT BA, BDU. translator to RWS Group Ltd, of Europa House. Marsham Way. Gerrards Cross, Buckinghamshire, England, state that the attached document is a true and complete translation to the best of my knowledge of International Patent Application No. PCT/EP2005/000332. Dated this 26th day of June 2006 Signature of Translator: " For and on behalf of RWS Group Ltd WO 2005/071314 PCT/EP2005/000332 Description Flexible parallel-flow burner with swirl chamber 5 The invention relates to an externally mixing burner with a burner head, at least one fuel gas pipe and at least one pipe for an oxygen-containing gas, the burner head having outlet openings from the fuel gas pipe and from the pipe for the oxygen-containing gas. 10 Furthermore, the invention relates to a method for operating an externally mixing burner which has at least one fuel gas pipe and at least one pipe for oxygen-containing gas, through which fuel gas or oxygen-containing gas respectively flow to the burner 15 head. Externally mixing burners are used for a wide variety of applications. For example, burners of different designs are used for heating and melting metals or 20 glass. Finding a burner that is suitable for all phases of the welding process and for different load cases of the furnace is a challenge here. The object of the present invention is therefore to 25 develop a burner which can be used for many applications and can be used advantageously for each phase of an application. The defined object is achieved by providing gas supply 30 lines for fuel gas and for oxygen-containing gas, which are each in connection with a source for fuel gas or for oxygen-containing gas respectively and of which at least one gas supply line opens out eccentrically into a swirl chamber which is mounted between the gas supply 35 line and the fuel gas pipe and/or between the gas supply line and the pipe for oxygen-containing gas.

WO 2005/071314 PCT/EP2005/000332 2 With preference, at least one of the gas supply lines divides upstream of the swirl chamber into two lines, one of these lines opening out eccentrically into the swirl chamber and the other of these lines opening out 5 directly into the fuel gas pipe or into the pipe for oxygen-containing gas. With particular preference, valves are provided in the gas supply lines, in particular valves are provided in 10 that part of the gas supply lines in which at least one gas supply line is already divided into two lines, and a controlling or regulating device is available, which controls or regulates the degrees of opening of the valves, whereby the shape of the flame of the burner 15 can be set. The valves are expediently formed as solenoid valves. These allow variable setting of the shape of the flame in stages. If greater requirements have to be met, 20 some or all of the solenoid valves may be replaced by regulating valves. These allow continuously variable setting of the shape of the flame. With preference, the swirl chamber has in a section 25 perpendicular to the longitudinal axis of the fuel gas pipe a circular cross section. With particular preference, the gas supply line opens out tangentially into the swirl chamber. Each of these refinements allows the friction for the swirl flow to be reduced 30 and altogether minimized. On the method side, the defined object is achieved by the fuel gas and/or the oxygen-containing gas being delivered eccentrically into a swirl chamber, in which 35 a swirl flow is imparted to the fuel gas or the oxygen containing gas and the fuel gas or oxygen-containing gas is fed to the fuel gas pipe or the pipe for oxygen- WO 2005/071314 PCT/EP2005/000332 3 containing gas respectively after leaving the swirl chamber. With preference, the amounts of fuel gas and oxygen 5 containing gas fed to the burner per unit of time via the swirl chamber and without the swirl chamber are controlled or regulated, the fuel gas and the oxygen containing gas being conducted via valves, the degrees of opening of which are controlled or regulated in such 10 a way that the burner produces a flame which has a shape that is as desired and can be set by means of the control or regulation. For example fuel-oxygen burners are often used for 15 firing industrial furnaces for melting metals or glass. In the combustion of fuel with air, the nitrogen contained in the air as the main constituent acts substantially as a ballast gas. To reduce the volume of exhaust gas, a change has taken place in favour of 20 operating the burners with an oxygen-containing gas as oxidizing agent, the oxygen content of which is increased in comparison with the oxygen content of air. This procedure has the advantage that, on account of the low nitrogen content, the temperature of the flame 25 is increased and the heat content in the exhaust gas is reduced, whereby higher thermal efficiency can be achieved and the formation of nitrogen oxides is advantageously reduced. 30 Both air and oxygen-containing gas with an oxygen content increased in comparison with the oxygen content of air are suitable as an oxidizing agent for the invention. The advantage of using air is that it is available constantly and at no cost. The advantages of 35 the higher oxygen content have already been explained. Air is b -- nily used as the oxygen-containing gas. It is available everywhere at no cost.

WO 2005/071314 PCT/EP2005/000332 -4 According to a further refinement of the invention, oxygen-enriched air is used as the oxygen-containing gas. This offers the advantage that it is still 5 inexpensive but already begins to have the advantages of using oxygen for the combustion, comprising the reduced nitrogen content in comparison with air and the higher achievable combustion temperature. 10 According to a preferred refinement of the invention, a gas with an oxygen content greater than the oxygen content of air, in particular with an oxygen content greater than 30% by volume, is used as the oxygen containing gas. The advantages just described of 15 oxygen in the oxidizing agent for combustion are more pronounced in the case of this refinement. According to a particularly preferred refinement of the invention, a gas with an oxygen content greater than 20 70% by volume, in particular greater than 99.5% by volume, is used as the oxygen-containing gas. In the case of this refinement, the advantages of oxygen are maximized, but the costs for the oxidizing agent accordingly increase, so that for each application it 25 should be considered which oxygen content is technically desirable or required and economically acceptable. With preference, a swirl flow is imparted to the fuel 30 gas flow. In this case, the advantage is that good mixing of the fuel with the oxygen is obtained, with a slightly shortened flame. According to another advantageous embodiment of the 35 invention, a swirl flow is imparted to the oxygen containing gas. This is advantageous, since, here, too, the flame is somewh-- shortened and the burner can be produced in a somewhat simpler structural form.

WO 2005/071314 PCT/EP2005/000332 5 According to a particularly preferred embodiment of the invention, swirl flows that are in the same direction as each other are imparted to the fuel gas flow and the 5 flow of the oxygen-containing gas. In this case, there is the advantage that the flame is very short and quiet. A further refinement of the invention provides that 10 swirl flows that are in opposite directions to each other are imparted to the fuel gas flow and the flow of the oxygen-containing gas. This is recommendable for the case in which an extremely short, bushy flame is required. 15 A major advantage of the invention is that the length of the flame can be changed infinitely variably (without changing the amount of fuel during operation). Also, no changes have to be made to the burner (such as 20 for example nozzle changes). The length of the flame at any time can therefore be reduced to a third of its maximum length. The invention is suitable in particular for processes 25 in which solid material is melted into liquid material, since here the melting materials change in their form and the shape of the flame can be adapted to this change. 30 A further great advantage of the invention is that the changing of the length of the flame takes place infinitely variably and the imparting of a swirl flow can be commenced and completed again during the operation of the burner, without the burner having to 35 be switched off and without any structural changes being necessary, such as for example changing the conventional swirl disk. Changing the shape of the flame takes place by changing at least one of the two WO 2005/071314 PCT/EP2005/000332 -6 gas flows alone by means of the setting of the degree of opening of the valves described, which in turn takes place by means of the controlling or regulating device which the invention has. 5 The externally mixing burner according to the invention is suitable in particular for melting metals or glass. The invention and further details of the invention are 10 explained more precisely below on the basis of an exemplary embodiment that is represented in the figures, in which: Figure 1 shows a burner according to the invention 15 Figure 2 shows a section along the line A - A Figure 3 shows a section along the line B - B. 20 To be specific, the figures show a burner 1 with a burner head 2, a pipe 4 for an oxygen-containing gas and with a fuel gas pipe 3 (not represented). The two pipes are concentrically arranged, to be precise in such a way that the fuel gas pipe 3 is mounted within 25 the pipe 4. A burner 1 constructed in such a way is also known as a parallel-flow burner. Natural gas is used for example as the fuel gas. The burner 1 is operated by way of example in such a 30 way that both gas flows are made to swirl in the same direction, as follows: when the valve 10 is open, natural gas flows from the gas supply line 6 via the line 6a into the swirl chamber 8. There, a swirl flow is imparted to the natural gas flow. The valve 11 is 35 in this case closed. Oxygen-enriched air is passed via the gas supply line 7 and the line 7a into the swirl chamber 9. There, a WO 2005/071314 PCT/EP2005/000332 - 7 swirl flow in the same direction as the natural gas flow is imparted to this gas flow. In this case, the valve 12 is open and the valve 13 is closed. 5 The flow of oxygen-enriched air leaves the swirl chamber and is delivered into the pipe 4. The natural gas flow is delivered into the fuel gas pipe 3. At the burner head 2, the two gas flows mix, and a 10 characteristic flame is produced. The shape of the flame produced depends directly on the setting of the valves 10, 11, 12 and 13. For example, the flame becomes longer if the fuel gas 15 flow is supplied with the valve 11 open and the valve 10 closed, i.e. no swirl flow is imparted to the natural gas flow. The flame is lengthened in comparison with the flame just described, in the case of which a swirl flow is imparted to both gas flows. 20 Similarly, only the natural gas flow may be made to swirl and the flow of oxygen-containing gas may be fed to the pipe 4 without any swirl, via the line 7b and the open valve 13. 25 By forming the valves 10, 11, 12 and/or 13 as regulating valves, intermediate positions are made possible, that is to say degrees of opening of these valves that can be set. As a result, the shape of the 30 flame can be adjusted infinitely variably. The changing of the shape of the flame takes place without any problem during the operation of the burner 1 by means of the controlling or regulating device for the valves 10, 11, 12, 13. 35 The supplied amounts of fuel gas and oxygen-containing gas must be taken as boundary conditions for the shape of the flame. Once chosen, the supplied amounts remain WO 2005/071314 PCT/EP2005/000332 -8 constant during the operation of the burner. A short, bushy and wide flame through to a long, narrow flame can only be produced by choosing the valve positions for the valves 10, 11, 12, 13.

Claims

1. An externally mixing burner (1) with a burner head (2), at least one fuel gas pipe (3) and at least 5 one pipe (4) for an oxygen-containing gas, the burner head (2) having outlet openings from the fuel gas pipe (3) and from the pipe (4) for the oxygen-containing gas, characterized in that gas supply lines (6, 7) for fuel gas and for oxygen 10 containing gas are provided, which are each in connection with a source for fuel gas or for oxygen-containing gas respectively and of which at least one gas supply line (6, 7) opens out eccentrically into a swirl chamber (8, 9) which is 15 mounted between the gas supply line (6) and the fuel gas pipe (3) and/or between the gas supply line (7) and the pipe (4) for oxygen-containing gas. 20

2. The burner (1) as claimed in claim 1, characterized in that at least one of the gas supply lines (6, 7) divides upstream of the swirl chamber (8, 9) into two lines (6a, 6b, 7a, 7b), one of these lines (6a, 7a) opening out eccentrically into the swirl 25 chamber (8, 9) and the other of these lines (6b, 7b) opening out directly into the fuel gas pipe (3) or into the pipe (4) for oxygen-containing gas.

3. The burner (1) as claimed in claim 1 or 2, 30 characterized in that valves (10, 11, 12, 13) are provided in the gas supply lines (6, 7), in particular valves in that valves (10, 11, 12, 13) are provided in that part of the gas supply lines (6, 7) in which at least one gas supply line (6, 7) 35 is already divided into two lines (6a, 6b, 7a, 7b), and a controlling or regulating device is available, which corI----ls or regulates the degrees of opening of the valves (10, 11, 12, 13), whereby WO 2005/071314 PCT/EP2005/000332 - 10 the shape of the flame of the burner (1) can be set.

4. The burner (1) as claimed in one of claims 1 to 3, 5 characterized in that the valves (10, 11, 12, 13) are formed as solenoid valves (10, 11, 12, 13).

5. The burner (1) as claimed in one of claims 1 to 4, characterized in that the swirl chamber (8, 9) has 10 in a section perpendicular to the longitudinal axis of the fuel gas pipe (3) a circular cross section.

6. The burner (1) as claimed in claim 5, characterized in that the gas supply line (6, 7, 6a, 7a) opens 15 out tangentially into the swirl chamber (8, 9).

7. A method for operating an externally mixing burner (1), which has at least one fuel gas pipe (3) and at least one pipe (4) for oxygen-containing gas, 20 through which fuel gas or oxygen-containing gas respectively flow to the burner head (2), characterized in that the fuel gas and/or the oxygen-containing gas is delivered eccentrically into a swirl chamber (8, 9), in which a swirl flow 25 is imparted to the fuel gas or the oxygen containing gas and the fuel gas or oxygen containing gas is fed to the fuel gas pipe (3) or the pipe (4) for oxygen-containing gas respectively after leaving the swirl chamber (8, 9). 30

8. The method as claimed in claim 7, characterized in that the amounts of fuel gas and oxygen-containing gas fed to the burner (1) per unit of time via the swirl chamber (8, 9) and without the swirl chamber 35 (8, 9) are controlled or regulated, the fuel gas and the oxygen-containing gas being conducted via valves (10, 11, 12, 13), the degrees nt opening of which are controlled or regulated in such a way WO 2005/071314 PCT/EP2005/000332 - 11 that the burner (1) produces a flame which has a shape that is as desired and can be set by means of the control or regulation. 5

9. The method as claimed in claim 7 or 8, characterized in that air is used as the oxygen containing gas.

10. The method as claimed in claim 7 or 8, 10 characterized in that oxygen-enriched air is used as the oxygen-containing gas.

11. The method as claimed in claim 7 or 8, characterized in that a gas with an oxygen content 15 greater than the oxygen content of air, in particular with an oxygen content greater than 30% by volume, is used as the oxygen-containing gas.

12. The method as claimed in claim 11, characterized in 20 that a gas with an oxygen content greater than 70% by volume, in particular greater than 99.5% by volume, is used as the oxygen-containing gas.

13. The method as claimed in one of claims 7 to 12, 25 characterized in that a swirl flow is imparted to the fuel gas flow.

14. The method as claimed in one of claims 7 to 13, characterized in that a swirl flow is imparted to 30 the flow of the oxygen-containing gas.

15. The method as claimed in one of claims 7 to 14, characterized in that swirl flows that are in the same direction as each other are imparted to the 35 fuel gas flow and the flow of the oxygen-containing gas. WO 2005/071314 PCT/EP2005/000332 - 12

16. The method as claimed in one of claims 7 to 14, characterized in that swirl flows that are in opposite directions to each other are imparted to the fuel gas flow and the flow of the oxygen 5 containing gas.

17. The use of the externally mixing burner (1) as claimed in one of claims 1 to 6 for melting metal or glass.