CA3113029A1

CA3113029A1 - Vortex combustion burner

Info

Publication number: CA3113029A1
Application number: CA3113029A
Authority: CA
Inventors: Kenneth Lawton
Original assignee: De Mission Inc
Current assignee: De Mission Inc
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2022-09-23
Also published as: CA3153242A1; WO2023178427A1; AR128866A1; TW202340649A

Abstract

A vortex combustion burner having a burner housing with a gas inlet through which a combustion gas is introduced into the burner housing, an air inlet through which combustion air is introduced into the burner housing and an outlet at a remote end of the burner housing. The remote end of the burner housing is where a fire tube is positioned. A
vortex generator associated with the burner housing creates a vortex flow. A
central rod has a proximal end anchored to the burner housing and a distal end extending past the remote end of the burner housing into the fire tube. The use of a central rod helps avoid a breakdown of the vortex flow, as the vortex tends to be maintained for the length of the central rod.

Description

TITLE
[0001] Vortex Combustion Burner FIELD

[0002] There is described an improvement to a vortex combustion burner.
BACKGROUND

[0003] A "vortex" is defined as a "mass of whirling fluid". A "vortex burner" is a combustion burner that has a vortex generator which creates a vortex. The vortex generator can take a number of forms, such tangential gas jets oriented to impart a whirling motion to gaseous fuel. U.S. Patent 5,697,776 (Van Eerden et al) titled "Vortex Burner"
is an example of a vortex burner.

[0004] Typically, combustion burners used with fire tubes generate very high temperatures at one end while the remainder of the fir e tube experiences a temperature gradient as the hot gases travel to the exit port.
A vortex burner stretches the gas combustion flame to distribute the heat more evenly over the length of the fire tube.

[0005] A vortex must spin at very high velocity to remain intact without breaking down into turbulent mixing. Although a vortex generator generates a fast rotating column of air, it is not fast enough to overcome turbulent combustion zone conditions and, as a result, the vortex rapidly breaks down.

[0006] Attempts have been made to address this problem by suggesting improvements to the vortex generator. Canadian Patent Application 3,102,511 (Garossino et al) titled "Combustion Burner With Fixed Vanes" discloses a combustion burner in which fixed vanes are used to improve the generation of a vortex.
SUMMARY

[0007] There is provided a vortex combustion burner having a burner housing with a gas inlet through which a combustion gas is introduced into the burner housing, an air inlet Date Recue/Date Received 2021-03-23 through which combustion air is introduced into the burner housing and an outlet at a remote end of the burner housing. The remote end of the burner housing is where a fire tube is positioned. A vortex generator associated with the burner housing creates a vortex flow. An igniter inlet is provided in the burner housing through which an igniter is inserted into the burner housing to ignite a mixture of the air and the gas. A central rod has a proximal end anchored to the burner housing and a distal end extending past the remote end of the burner housing into the fire tube.

[0008] The use of a central rod helps avoid a breakdown of the vortex flow, as the vortex tends to be maintained for the length of the central rod. While the fuel and air are mixed in the rotating vortex flowing along the inner rod, combustion occurs only at the outside of the vortex. The burnt gases resulting from combustion being hot and less dense are forced radially outward to remain in contact with the circumference of the fire tube, while the more dense unburnt air and fuel stretch the flame down the entire length of the fire tube.

[0009] When a fire tube is attached to the remote end of the burner housing, it is preferred that the central rod extend for most of the length of the fire tube. It will be appreciated, however, that the described benefits can be obtained even if the central rod only extends partially down the fire tube.

[0010] Although beneficial results may be obtained through the use of a central rod that is inert, it is preferred that the central rod is made from a heat conducting material. The central rod will become glowing hot during use and will serve as a secondary ignitor for unburnt air and fuel. Beneficial results have been obtained when the heat conducting material is metal or ceramic.

[0011] A centralizer support is used to centre and support central rod within the burner housing. Although beneficial results may be obtained through the use of vortex combustion burner, as described above, even more beneficial results may be obtained when the centralizer support is an electric insulator, which electrically insulates the central rod from Date Recue/Date Received 2021-03-23 the burner housing. When electrically isolated, the central rod may be used as a flame rectification rod for a flame detection system.

[0012] There are a number of ways of configuring a vortex generator to generator the desired flow. As described above, tangential gas jets may be oriented to impart a whirling motion or fixed vanes may be provided to impart a whirling motion. In the detailed description, the air inlet is tangential to the central rod and forced air, in combination with the tangential orientation of the air inlet, function as a vortex generator to induce a helical flow. Even more beneficial results may be obtained when a reducer having a decreasing diameter is positioned in the air inlet to further increase air velocity as air enters the burned housing.

[0013] In order to function, as described above, central rod may be solid or hollow. It is preferred that the central rod is hollow and defines an annular bore. This enables a supplemental fluid inlet to be is connected to the annular bore at the proximal end of the central rod, thereby providing a flow of fluid from the proximal end to the distal end of the central rod. The type of fluid used will depend upon the intended application.
The fluid may be waste gas from another process. The fluid may be make up air.
BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:

[0015] FIG.
1 is a side elevation view of a vortex combustion burner connected to a fire tube.

[0016] FIG.
2 is a section view of the vortex combustion burner connected to a fire tube taken along section lines A-A of FIG 1.

[0017] FIG.
3 is a side elevation view of the vortex combustion burner, with fire tube removed.

[0018] FIG. 4 is section view taken along section lines B-B of FIG. 3.

Date Recue/Date Received 2021-03-23 DETAILED DESCRIPTION

[0019] A
vortex combustion burner generally identified by reference numeral 10, will now be described with reference to FIG. 1 through FIG. 4.
.. Structure and Relationship of Parts:

[0020]
Referring to FIG. 3, vortex combustion burner 10 has a burner housing 12 with a gas inlet 14 through which a combustion gas is introduced into burner housing and an air inlet 16 through which combustion air is introduced into burner housing 12.
Referring to FIG. 2, there is an outlet 18 at a remote end 20 of burner housing 12.
Referring to FIG. 1 and FIG. 2, a fire tube 100 is attached to remote end 20 of burner housing 12.
This can be a permanent attachment, such as welding, or a removable attachment using a form of a coupling 101. Fire tube 100 and coupling 101 have been identified by a different number sequence [100 & 1011, as fire tube 100 and coupling 101 can be added later and does not have to be sold with vortex combustion burner 10.

[0021]
Referring to FIG. 2, a vortex generator, generally identified by reference numeral 24, is associated with burner housing 12 and creates a vortex flow as will hereinafter be further described.

[0022] Referring to FIG. 1 and FIG. 3, an igniter inlet 26 is provided in burner housing 12 through which an igniter 102 is inserted into burner housing 12 to ignite a mixture of the air from air inlet 16 and the gas from gas inlet 14. Igniter 102 has been identified by a different number sequence [102], as the igniter 102 can be added later and does not have to be sold with vortex combustion burner 10.

[0023]
Referring to FIG. 2 and FIG. 3, a central rod 28 is provided that has a proximal end 30 anchored to burner housing 12 and a distal end 32 extending past remote end 20 of burner housing 12 into fire tube 100. The positioning of central rod defines an annulus 29.

[0024] Referring to FIG. 2, a blower 104 [a displacement pump could be used as an Date Recue/Date Received 2021-03-23 alternative] is connected to air inlet 16. Referring to FIG. 4, an adaptor 34 is positioned in air inlet 16. Blower 104 creates a flow of forced air through air inlet 16.
Adaptor 34 ensures that the flow of forced air is tangential to central rod 28. This features functions as vortex generator 24 to induce a helical flow around central rod 28. It is preferred that adaptor 34 have a reducer portion 36 of decreased diameter to further increase air velocity entering blower housing 12. It will be appreciated that if air inlet 16 is positioned tangentially, adaptor 34 is not required, except for the purpose of functioning as a reducer. Blower 104 has been identified by a different number sequence [104], as the blower 104 can be added later and does not have to be sold with vortex combustion burner 10.

[0025] Referring to FIG. 2, when fire tube 100 is attached to remote end 20 of burner housing 12, it is preferred that central rod 28 extend for most of the length of the fire tube in order to get the maximum benefit of the use of central rod 28. As will hereinafter be described, this extends the vortex region for the length of fire tube 100. It is preferred that central rod 28 is made from a heat conducting material, such as metal or ceramic. This facilitates central rod 28 glowing hot during use and enables central rod 28 to serve as a secondary ignitor for unburnt air and gas. As will hereinafter be further described, this extends the combustion zone for the length of fire tube 100.

[0026] Referring to FIG. 2, a series of centralizer supports 38 are used to centre and support central rod 28 within burner housing 12. It is preferred that each centralizer support 38 is an electric insulator, which electrically insulates central rod 28 from burner housing 12.
When electrically isolated, central rod 28 may be used as a flame rectification rod for a flame detection system. The use of flame detection systems are known in the art and will not be further described.

[0027] Referring to FIG. 2, it is preferred that central rod 28 is hollow and defines an annular bore 40. This enables a supplemental fluid inlet 42 to be is connected to annular bore 40 at proximal end 30 of central rod 28. This provides a path for a flow of fluid from the proximal end 30 to distal end 32 of central rod 28.

Date Recue/Date Received 2021-03-23

[0028] Referring to FIG. 1 and FIG. 2, a quartz window port 44 is provided for a flame detection system such as is sold under the Trademark "FireEye".
Operation:

[0029] Referring to Fig. 2, forced air from blower 104 is supplied to air inlet 16.
Referring to FIG. 4, air passes through adaptor 34 which positions the flow of forced air tangential to central rod 28. Reducer portion 36 of adaptor 34 assists in adding further velocity to the forced air entering burner housing 12. Referring to FIG. 1, igniter 102 is extends into burner housing 12 through igniter inlet 26 and serves to ignite a mixture of the air from air inlet 16 and the gas from gas inlet 14. When the mixture of air and gas is ignited, vortex combustion burner 10 produces a rapidly rotating flame which wraps around central rod 28. Whereas formerly the vortex would decay in the turbulent flow caused by combustion, the use of central rod 28 helps maintain the vortex for substantially the entire length of central rod 28.

[0030] The reason central rod 28 is able to maintain the vortex is directly related to the manner in which combustion occurs. While the fuel and air are mixed in the rotating vortex flowing along central rod 28, combustion occurs only at the outside of the vortex. The burnt gases resulting from combustion being hot and less dense are forced radially outward to remain in contact with the circumferential interior sidewall of fire tube 100, while the more dense unburnt air and fuel stretch the flame down the entire length of fire tube 100.

[0031] In operation, the air and fuel ratio adjusted between stoichiometric and excess oxygen. The volume and mixture can be varied over a large dynamic range dependent upon fuel gas caloric content. It is preferred that central rod 28 extend for most of the length of the fire tube. This enables the flame and subsequent thermal energy to be stretched along central rod 28 and distributed evenly across the length of fire tube 100. This is highly desirable where fire tube is intended for use as a heat exchanger for heating gases and liquids.

Date Recue/Date Received 2021-03-23

[0032] As described above, central rod 28 can be solid and achieve the benefits described. Referring to FIG. 2, it is preferred that central rod 28 is hollow and defines an annular bore 40. This enables a supplemental fluid inlet 42 to be is connected to annular bore 40 at proximal end 30 of central rod 28. This provides a path for a flow of fluid from the proximal end 30 to distal end 32 of central rod 28. Depending upon what is intended to be achieved, the flow of fluid could be waste gases from another process introduced for the purpose of incineration. The flow of fluid could be supplemental oxygen introduced for the purpose of providing additional oxygen for combustion. The feature makes vortex combustion burner more versatile for use in different applications.

[0033] In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

[0034] The scope of the claims should not be limited by the illustrated embodiments set forth as examples, but should be given the broadest interpretation consistent with a purposive construction of the claims in view of the description as a whole.

Date Recue/Date Received 2021-03-23

Claims

What is Claimed is:

1. A vortex combustion burner, comprising:
a burner housing having a gas inlet through which a combustion gas is introduced into the burner housing, an air inlet through which combustion air is introduced into the burner housing and an outlet at a remote end of the burner housing, the remote end having means for attaching a fire tube;
a vortex generator to create a vortex flow;
an igniter inlet through which an igniter is inserted into the burner housing to ignite a mixture of the air and the gas; and a central rod having a proximal end anchored to the burner housing and a distal end extending past the remote end of the burner housing into the fire tube.

2. The vortex combustion burner of Claim 1, with a fire tube attached to the remote end of the burner housing.

3. The vortex combustion burner of Claim 2, wherein the central rod extends for most of the length of the fire tube.

4. The vortex combustion burner of Claim 1, wherein the central rod is made from a heat conducting material.

5. The vortex combustion burner of Claim 4, wherein the heat conducting material is one of metal or ceramic.

6. The vortex combustion burner of Claim 1, wherein a centralizer support is used to centre and support central rod within the burner housing.

7. The vortex combustion burner of Claim 6, wherein the centralizer support is an electric Date Recue/Date Received 2021-03-23 insulator, which electrically insulates the central rod from the burner housing.

8. The vortex combustion burner of Claim 1, wherein the air inlet is tangential to the central rod and forced air, in combination with the tangential orientation of the air inlet, functions as a vortex generator to induce a helical air flow.

9. The vortex combustion burner of Claim 8, wherein a reducer having a decreasing diameter is positioned in the air inlet to further increase air velocity.

10. The vortex combustion burner of Claim 1, wherein the central rod is hollow and defines an annular bore and a supplemental fluid inlet is connected to the annular bore at the proximal end of the central rod, thereby providing a flow of fluid gas from the proximal end to the distal end of the central rod.

Date Recue/Date Received 2021-03-23