WO2023178427A1

WO2023178427A1 - Vortex combustion burner

Info

Publication number: WO2023178427A1
Application number: PCT/CA2023/050373
Authority: WO
Inventors: Kenneth Arnold Lawton
Original assignee: De.Mission Inc.
Priority date: 2021-03-23
Filing date: 2023-03-22
Publication date: 2023-09-28
Also published as: TW202340649A; CA3153242A1; CA3113029A1

Abstract

A vortex combustion burner is disclosed. Air and a gas for combustion are introduced into a burner housing via at least one inlet thereof. An outlet at a remote end of the burner housing is configured to attach to a fire tube. A central rod has a proximal end anchored to the burner housing and a distal end extending past the remote end into the fire tube. A vortex generator induces a helical flow of a mixture of the air and the gas around the central rod. An igniter is inserted into the burner housing via an igniter inlet of the burner housing to ignite the mixture.

Description

VORTEX COMBUSTION BURNER

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Canadian Patent Application No. 3,153,242, filed on 23 March 2022.

TECHNICAL FIELD

This disclosure generally relates to burners and combustion devices, and more particularly to vortex combustion burners.

BACKGROUND

A “vortex” may refer to 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. For example, an example of a vortex burner is disclosed in U.S. Patent 5,697,776 (Van Eerden et al) titled “Vortex Burner”. Typically, combustion burners used with fire tubes generate very high temperatures at one end while the remainder of the fire 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. A vortex generally spins 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 may not move fast enough to overcome turbulent combustion zone conditions and, as a result, the vortex rapidly breaks down. Attempts have been made to address such issues by suggesting improvements to the vortex generator.

SUMMARY

There is disclosed 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. 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.

There is disclosed a vortex combustion burner. The vortex combustion burner also includes a burner housing defining at least one inlet through which air and a gas for combustion are introduced into the burner housing, a remote end configured to attach to a fire tube, and an outlet at the remote end. The vortex combustion burner also includes a central rod having a proximal end anchored to the burner housing and a distal end extending past the remote end into the fire tube; a vortex generator to induce a helical flow of a mixture of the air and the gas around the central rod; and an igniter inlet through which an igniter is inserted into the burner housing to ignite the mixture.

It is found that the use of a central rod generally 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 may only at the outside of the vortex. The burnt gases resulting from combustion being hot and less dense may be forced radially outward to remain in contact with the circumference of the fire tube, while the more dense unbumt air and fuel stretch the flame down the entire length of the fire tube.

When a fire tube is attached to the remote end of the burner housing, it may be particularly advantageous that the central rod extends for most, or substantially all, of a 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.

Although beneficial results may be obtained through the use of a central rod that is inert, it may be particularly advantageous that the central rod is made from a heat conducting material. The central rod may become glowing hot during use and may serve as a secondary ignitor for unbumt air and fuel. For example, beneficial results have been obtained when the heat conducting material is metal or ceramic.

A centralizer support may be 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 the burner housing. When electrically isolated, the central rod may be used as a flame rectification rod for a flame detection system. 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. For example, the vortex generator may define an air inlet tangential to the central rod such that forced air passing through the air inlet induces the helical air flow. In the detailed description, the air inlet is described as 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 the 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.

In order to function, as described above, central rod may be solid or hollow. It is found to be particularly advantageous that the central rod is hollow so as to define 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 to provide a flow of fluid from the proximal end to the distal end of the central rod. The type of fluid used may depend upon the intended application. The fluid may be waste gas from another process. The fluid may be made up of air.

Embodiments can include combinations of the above features.

Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description included below and the drawings.

DESCRIPTION OF THE DRAWINGS

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:

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

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;

FIG. 3 is a side elevation view of the vortex combustion burner, with fire tube removed; and

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

DETAILED DESCRIPTION

A vortex combustion burner 10, will now be described with reference to FIG. 1 through FIG. 4. STRUCTURE AND RELATIONSHIP OF PARTS

Referring to FIG. 3, the vortex combustion burner 10 has a burner housing 12 with at least one inlet. The at least one inlet may include 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 the burner housing 12. Referring to FIG. 2, there is an outlet 18 at a remote end 20 of the burner housing 12. Referring to FIG. 1 and FIG. 2, a fire tube 100 is attached to the remote end 20 of the burner housing 12. This may be a permanent attachment, such as welding, or a removable attachment using a form of a coupling 101. In various embodiments, the fire tube 100 and the coupling 101 may be separate components that may be added later, e.g. they may not have to be sold with the vortex combustion burner 10.

Referring to FIG. 2, a vortex generator 24, is associated with the burner housing 12 and creates a vortex flow as will hereinafter be further described.

Referring to FIG. 1 and FIG. 3, an igniter inlet 26 is provided in the burner housing 12 through which an igniter 102 is inserted into the burner housing 12 to ignite a mixture of the air from the air inlet 16 and the gas from the gas inlet 14. In various embodiments, the igniter 102 may be a separate component that may be added later, e.g. it may have to be sold with the vortex combustion burner 10.

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

Referring to FIG. 2, a blower 104 is connected to air inlet 16. In various embodiments, a displacement pump may be used instead of the blower 104. In various embodiments, a turbomachine for forcing air through the air inlet 16 may be used. Referring to FIG. 4, an adaptor 34 is positioned in the air inlet 16. The blower 104 may create a flow of forced air through the air inlet 16. The adaptor 34 may ensure that the flow of forced air is tangential to the central rod 28. These features may function as the vortex generator 24 to induce a helical flow around the central rod 28. It is found that it is particularly advantageous that the adaptor 34 may have a reducer portion 36 of decreased diameter to further increase air velocity entering or blowing into the burner housing 12. It will be appreciated that if air inlet 16 is positioned tangentially, the adaptor 34 may not required, except for the purpose of functioning as a reducer. In various embodiments, the blower 104 may be a separate component that may be added later, e.g. it may have to be sold with the vortex combustion burner 10.

Referring to FIG. 2, when the fire tube 100 is attached to the remote end 20 of the burner housing 12, it is found particularly advantageous that the central rod 28 extend for most, or substantially all, of the length of the fire tube 100 in order to get achieve greater or possibly the greatest benefit of the use of the central rod 28. As will hereinafter be described, this may extend the vortex region for up to the length of the fire tube 100. It is found to be particularly advantageous that the central rod 28 is made from a heat conducting material, such as metal or ceramic. This may facilitate the central rod 28 glowing hot during use and may enable the central rod 28 to serve as a secondary ignitor for unbumt air and gas. As will hereinafter be further described, this may extend the combustion zone for up to the length of the fire tube 100.

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

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

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

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

Without being bound by theory, it is proposed that the reason that the central rod 28 is able to maintain the vortex may be directly related to the manner in which combustion occurs. For example, while the fuel and the air are mixed in the rotating vortex flowing along central rod 28, combustion may occur only at the outside of the vortex. For example, the burnt gases resulting from combustion being hot and less dense may be forced radially outward to remain in contact with the circumferential interior sidewall of the fire tube 100, while the more dense unbumt air and fuel may stretch the flame down the entire length of the fire tube 100.

In operation, the air and fuel ratio may be 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 found to be particularly advantageous that the central rod 28 extend for most, or substantially all, of the length of the fire tube 100. This may enable the flame and subsequent thermal energy to be stretched along the central rod 28 and distributed evenly across the length of fire tube 100. This may be highly desirable where the fire tube 100 is intended for use as a heat exchanger for heating gases and liquids.

As described above, in some embodiments, the central rod 28 may be solid and achieve the benefits described. Referring to FIG. 2, it is found particularly advantageous that the central rod 28 is hollow so as to define the annular bore 40. This may enable the supplemental fluid inlet 42 to be connected to the annular bore 40 at the proximal end 30 of the central rod 28. This provides a path for a flow of fluid from the proximal end 30 to the distal end 32 of the central rod 28. In various embodiments, 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. For example, the flow of fluid could be supplemental oxygen introduced for the purpose of providing additional oxygen for combustion. This feature may make the vortex combustion burner 10 more versatile for use in various applications.

The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. For example, a non-hollow central rod may be used. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.

Claims

WHAT IS CLAIMED IS:

1. A vortex combustion burner, comprising: a burner housing defining at least one inlet through which air and a gas for combustion are introduced into the burner housing, a remote end configured to attach to a fire tube, and an outlet at the remote end; a central rod having a proximal end anchored to the burner housing and a distal end extending past the remote end into the fire tube; a vortex generator to induce a helical flow of a mixture of the air and the gas around the central rod; and an igniter inlet through which an igniter is inserted into the burner housing to ignite the mixture.

2. The vortex combustion burner of claim 1, wherein the at least one inlet comprises: a gas inlet through which the gas is introduced into the burner housing; and an air inlet through which the air is introduced into the burner housing.

3. The vortex combustion burner of claim 1, with the fire tube attached to the remote end of the burner housing.

4. The vortex combustion burner of claim 3, wherein the central rod extends past the remote end into the fire tube for most of a length of the fire tube.

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

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

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

8. The vortex combustion burner of claim 7, wherein the centralizer support is an electric insulator for electrically insulating the central rod from the burner housing.

9. The vortex combustion burner of claim 1, wherein the vortex generator defines an air inlet tangential to the central rod such that forced air passing through the air inlet induces the helical air flow.

10. The vortex combustion burner of claim 9, wherein a reducer having a decreasing diameter is positioned in the air inlet to increase velocity of the forced air.

11. The vortex combustion burner of claim 1, wherein the at least one inlet comprises an air inlet through which the air is introduced into the burner housing and that is tangential to the central rod, and the vortex generator comprises a blower to create a flow of forced air through the air inlet so as to induce the helical flow.

12. The vortex combustion burner of claim 1, wherein the central rod is hollow so as to define an annular bore, a supplemental fluid inlet being connected to the annular bore at the proximal end of the central rod to provide a flow of gas from the proximal end to the distal end of the central rod.