Glycerin burning system

Abstract

A glycerin burning system having a specialized atomizing burner capable of combusting a continuous feed of crude or pure glycerin. The burner preferably includes an impingement nozzle. The nozzle has an internal distributor which mixes two fluid feed streams (glycerin and air) and expels the fluid through an orifice. The distributor has channels which cause the air to swirl before mixing with the glycerin. An impingement pin is provided outside the orifice. The rapidly ejected glycerin/air mixture strikes a target surface on the impingement pin which transforms the mixture into a fine mist having a reduced velocity. The nozzle is located on the central axis of a turbulator which surrounds the atomized spray with rapidly revolving air. An outlet choke is provided on the combustion chamber to limit the speed of the flow so that steady combustion is maintained.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

MICROFICHE APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of waste product combustion. More specifically, the present invention comprises a glycerin burning system having a specialized atomizing nozzle for the combustion of glycerin.

2. Description of the Related Art

Glycerin, or glycerol, is a byproduct of biodiesel and soap manufacturing. Although there are various uses for pure glycerin, the increase in demand for biodiesel has resulted in the production and stockpiling of large quantities of crude glycerin. This trend is expected to continue.

Currently there is a need for effective combustion systems for the disposal and heat recovery of glycerin. The most effective glycerin combustion systems typically require a substantial amount of combustion enhancer (an alternate fuel source) to be added to the glycerin in order to achieve the complete combustion of the glycerin. This adds significant cost to the process.

Existing burners cannot burn pure glycerin because the combustion air speed produced by conventional burners exceeds the flame propagation speed of the air-glycerin mixture. Even if one is able to instantaneously ignite the air-glycerin mixture the flame will be quickly blown away by the burner (a “flame out”). This phenomenon is a major obstacle to the development of effective glycerin combustion systems. An additional fuel—such as alcohol—has traditionally been mixed with the glycerin to increase the flame propagation speed. However, the cost of the alcohol makes the entire process unprofitable. Accordingly, it would be desirable to provide a glycerin burning system which reduces or eliminates the need for a combustion enhancer.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a glycerin burning system having a specialized atomizing burner capable of combusting a continuous feed of crude or pure glycerin. The burner preferably includes an impingement nozzle. The nozzle has an internal distributor which mixes two fluid feed streams (glycerin and air) and expels the fluid through an orifice. The distributor has channels which cause the air to swirl before mixing with the glycerin. An impingement pin is provided outside the orifice. The rapidly ejected glycerin/air mixture strikes a target surface on the impingement pin which transforms the mixture into a fine mist having a reduced velocity.

The nozzle is located on the central axis of a turbulator. The turbulator feeds an additional volume of rapidly moving air around the nozzle. The turbulator includes a set of angled vanes which impart substantial rotation and turbulence to the air as it passes through the device. This air stream collides with the mist of air/glycerin coming off the target surface of the impingement pin. The result is a widely diffused and highly turbulent mixture of air and glycerin.

This mixture is propelled into a cylindrical combustion chamber where it ignites and burns in a swirling fashion. The far end of the combustion chamber is closed by a choke wall having a choke outlet. The choke outlet is an opening having an area which is smaller than the cross sectional area of the combustion chamber. The opening “chokes” the flow in order to reduce the combustion speed within the combustion chamber and thereby maintain the combustion speed below the flame propagation speed of the air/glycerin mixture.

The burning system preferably includes the ability to start on a secondary fuel or secondary fuel/glycerin mixture in order to pre-heat the combustion chamber and other components. The system preferably also includes a water purging system to clean the feed lines and combustion chamber when a burning cycle is completed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic illustration of a glycerin burning system.

FIG. 2 is a side view, showing a burner for use with the glycerin burning system.

FIG. 3 is a side view, illustrating the operation of the burner.

FIG. 4 is an exploded perspective view, showing an impingement mixing nozzle for use with the burner.

FIG. 5 is a perspective view, showing a distributor for use with the impingement mixing nozzle.

FIG. 6 is a section view, illustrating the operation of the impingement nozzle.

FIG. 7 is an elevation view, showing the exit plane of the turbulator.

FIG. 8 is a perspective view, showing the orientation of the flow-directing vanes in the turbulator.

FIG. 9 is an exploded perspective view, showing the fuel feed line, the turbulator, and the nozzle.

FIG. 10 is a perspective view, showing the combustion chamber housing.

FIG. 11 is a sectioned elevation view, showing the burner attached to the combustion chamber housing.

FIG. 12 is a sectioned elevation view, showing the burner in operation.

REFERENCE NUMERALS IN THE DRAWINGS

10	glycerin burning system	12	combustion chamber
14	wall	16	port
18	conduit	20	burner
22	nozzle	24	port
26	exhaust	28	fuel pump
30	fuel cutoff solenoid	32	air tube
34	impingement pin	36	flame retention head
38	fuel feed	40	check valve
42	purge fluid solenoid	44	ignition transformer
46	manifold	48	check valve
50	starter feed	52	water feed
54	vents	56	orifice
58	conduit	60	receiver
62	distributor	64	fuel feed connector
66	conduit	68	channels
70	swirl channels	72	orifice
74	surface	76	surface
78	combustion zone	80	target surface
82	turbulator	84	housing
86	vane	88	central passage
90	central axis	92	mounting flange
94	combustion chamber housing	96	cylindrical wall
98	choke wall	100	choke outlet
102	mounting wall	104	spray pattern
106	exhaust flame	108	flame front
110	burner inlet

DETAILED DESCRIPTION OF THE INVENTION

The present invention, glycerin burning system 10 is illustrated in FIG. 1. Glycerin burning system 10 may be used to burn a continuous feed of raw or pure glycerin. Glycerin burning system 10 generally includes burner 20 which expels glycerin through nozzle 22 into combustion chamber 12 where the glycerin is combusted in combustion zone 78. Exhaust gases are vented to the atmosphere through exhaust 26. Air is fed to burner 20 by a burner air blower and a portion of the air fed to burner 20 is diverted into conduit 18 which wraps around wall 14 of combustion chamber 12. Conduit 18 may be the interior region of a “jacket” surrounding wall 14 or any other conduit suitable for directing the flow of air around combustion chamber 12 while allowing the air to exchange heat with combustion chamber 12. Ports 24 and 16 are provided in wall 14 and direct heated air toward combustion zone 78. The direction of hot air towards combustion zone 78 serves two synergistic functions. First, the hot air helps atomize the glycerin expelled from burner 20. Second, the air flow reduces the effective air velocity of air exiting burner 20. These two functions work together to mitigate “flare out.” Flare out occurs when the combustion air velocity exceeds the flame propagation speed in the glycerin-air mixture.

FIG. 2 illustrates burner 20 in greater detail. Burner 20 includes fuel pump 28 which pressurizes the glycerin feeding into burner 20. During glycerin combustion operations, glycerin passes through fuel cutoff solenoid 30 (when in the open position) through check valve 40 into manifold 46 where it is fed to fuel feed line 38. Ignition transformer 44 provides a spark to ignite the fuel after it exits nozzle 22 and strikes impingement pin 34. Starter feed 50 is provided for supplying a feed of a starter fuel (such as alcohol or an alcohol-glycerin mixture) to burner 20 during start-up. The starter fuel is used to heat the combustion chamber to a designed operating temperature before switching to a pure glycerin feed. The starter fuel is supplied to fuel feed line 38 though check valve 48 and manifold 46. An exterior pump is used to supply the starter fuel to burner 20.

Water is used to purge burner 20, thus cleaning the internal components thereof, upon the cessation of combustion operations. Water is supplied to burner 20 though water feed 52. Purge fluid solenoid 42 regulates the flow of water to burner 20. Like the starter fuel, an exterior pump supplies water to water feed 52.

Air is supplied to burner 20 by a burner air blower. As mentioned previously, a portion of this air feed is directed into the conduit wrapping around the combustion chamber. The other portion is fed into air tube 32. Turning to FIG. 3, a portion of the air fed into air tube 32 is diverted through vents 54 in flame retention head 36. Flame retention head 36 helps provide a broad, stable combustion air flow to promote even flame propagation. As mentioned previously, the glycerin is expelled through nozzle 22 where it strikes the tip of impingement pin 34, diffuses, and mixes with combustion air.

FIG. 4 shows a detailed view of nozzle 22. Nozzle 22 is an internal mix nozzle in which a portion of the combustion air is mixed with the glycerin feed as the glycerin passes through conduit 58 and orifice 56 and strikes impingement pin 34. Distributor 62 rests inside receiver 60. Distributor 62, which imparts rotation to the air feed before the air feed begins mixing with the glycerin feed, is shown in greater detail in FIG. 5. Distributor 62 has fuel feed connector 64 which connects distributor 62 to the fuel feed line of the burner. Fuel passing through the feed line passes through conduit 66 within distributor 62 and out orifice 72. Air passes around distributor 62 through channels 68 into swirl channels 70. Surfaces 74 and 76 mate with the interior of receiver 60 so that air passing around distributor 62 is forced through channels 68 and swirl channels 70. Swirl channels 70 impart rotation to the air feed by directing the air in angularly about the central axis of conduit 66. This rotation aids in the mixing and atomization of the glycerin feed as it exits the nozzle.

FIG. 6 is a section view of nozzle 22 with distributor 62 omitted for greater clarity. Glycerin exiting orifice 72 of conduit 66 is picked up by the rotational air flow passing around distributor. The glycerin passes through conduit and out orifice 56 where it impinges against target surface 80 of impingement pin 34. This diffuses the air-glycerin mixture, reflecting a portion of the stream back onto the stream exiting orifice 56. This creates more collision between glycerin and air particles and greater diffusion around impingement pin 34. This also reduced the velocity of the stream. The glycerin and air mixture passes around impingement pin 34 as a fine mist or fog. Such a nozzle design both reduces combustion air speed and atomizes the glycerin feed for improved flame propagation.

With the various components of the glycerin burning system now described, operation of the glycerin burning system will be described in greater detail. During start-up, starter fuel is fed to burner 20 through starter feed 50. The starter fuel passes through check valve 48 and into manifold 46 before passing through fuel feed 38. Ignition transformer 44 produces a spark as the starter fuel exits nozzle 22. Starter fuel is fed to burner 20 for a sufficient period of time to heat the combustion chamber to the desired temperature.

When the desired temperature is reached, fuel pump 28 feeds fuel to manifold 46 through check valve 40. In order to do this, fuel cutoff solenoid 30 is moved to the open position. The fuel is fed to nozzle 22 where it is atomized and combusted. Check valve 48 prevents the fuel from being forced into starter feed 50.

Upon cessation of combustion operations, fuel cutoff solenoid 30 is moved to the closed position and purge fluid solenoid 42 is opened. Water or other purging fluid is fed to burner 20 via water feed 52. The water passes through purge fluid solenoid 42 into manifold 46. The water then passes out of burner 20 through fuel feed 38 and nozzle 22. This cleans the internal components of burner 20 and nozzle 22 to insure that burner 20 and nozzle 22 will last many burning cycles without “gumming up.” Check valve 40 and check valve 48 prevent the purge fluid from passing back into the fuel and starter fluid feed lines.

A second embodiment of the glycerin burning system is illustrated in FIGS. 8-12. As discussed previously, it is important to reduce the combustion speed of the glycerin and air mixture so that a “flame out” does not occur. One approach to reducing the combustion speed is to enhance the dispersion of the atomized glycerin/air mixture at the point where it is injected into the combustion chamber. The second embodiment used a turbulator in combination with an impingement nozzle to enhance the dispersion.

FIG. 7 shows an elevation view of turbulator 82. A hollow cylindrical housing 84 defines the outer perimeter of the device. A plurality of radially spaced vanes 86 extend inward from the housing. Central passage 88 remains open to receive the nozzle assembly—as will be described subsequently.

FIG. 8 shows the exit plane of the turbulator in a perspective view. The reader will note that each vane 86 is angularly offset with respect to central axis 90 (which runs through the center of the housing). In the embodiment shown, each vane is offset approximately 45 degrees from the central axis. The angled vanes force air flowing through the housing to rotate as it exits the housing. In addition, the reader will observe that each vane extends substantially beyond the end of the housing. This fact means that as the air is rotating faster, it escapes the confinement of the housing. Centrifugal force then forces the air to flow outward. The result is a turbulent, spinning air flow which expands outward as it escapes the turbulator.

FIG. 9 is an exploded perspective view which illustrates how the nozzle assembly is located within the turbulator. Nozzle 22 lies along central axis 90. Fuel feed 38 passes through the turbulator and connects to nozzle 22 when it is in position. Central passage 88 is preferably sized to just accommodate the diameter of the nozzle. When the nozzle is in position a gap is formed between the turbulator housing and the nozzle. The canted vanes preferably fill substantially all of this gap.

Mounting flange 92 is provided to mount the turbulator to a combustion chamber housing. The mounting hardware is not significant to the present invention, so the flange illustrated should properly be viewed as one example among many possibilities.

FIG. 10 shows combustion chamber housing 94, which is configured for use with the turbulator and nozzle assembly previously illustrated. Cylindrical wall 96 joins a mounting wall on the far side of the view (not shown) and choke wall 98 on the near side of the view. Choke wall 98 includes choke outlet 100.

The combustion chamber housing is generally not made of a unitary material. Rather, it is typically made as a steel weldment with a refractory layer on its inner surfaces. However, the material and method of construction of this component is well known to those skilled in the art and—accordingly—it will not be described in further detail.

FIG. 11 shows a sectioned elevation view with burner 20 being assembled to the combustion chamber housing. Burner 20 is conventionally attached to mounting wall 102—though this need not always be the case. Combustion chamber 12 is defined by cylindrical wall 96, mounting wall 102, and choke wall 98. Burner 20 is directed toward choke outlet 100 in choke wall 98.

Nozzle 22 rests in the middle of turbulator 82. Fuel feed 38 passes through the turbulator to the nozzle. Pressurized air must be fed into the turbulator housing using any suitable duct (not shown. As discussed previously, pressurized air must also be fed to the nozzle to feed swirl channels 70 (see FIGS. 4-6).

FIG. 12 shows the assembly in operation. Pressurized air is fed through turbulator 82. Pressurized glycerin is fed to the nozzle through fuel feed 38. The swirling turbulator air and wide dispersion from the impingement nozzle produce a wide spray pattern 104. This spray pattern contains a turbulent mist of glycerin in air. This mixture is ignited to produce a rolling, turbulent flame front 108.

Choke outlet 100 is sized to retain the flame front within the combustion chamber housing—in order to avoid a “flame out.” For given feed pressures of air and glycerin, the choke outlet may be sized to produce a steady combustion state in which flame front 108 is appropriately positioned within combustion chamber 12. RExhaust flame 106 extends out through choke outlet 100. The heat of the exhaust may be captured to drive an energy recovery device such as a steam turbine. In a more sophisticated embodiment, the diameter of choke outlet 100 could be varied using devices such as are employed on afterburner-equipped jet aircraft engines.

The flow of gas and combustion products is decelerated to balance the flame propagation speed of the glycerin/air mixture. As the glycerin/air mixture can be difficult to consistently ignite, it is desirable to provide alternate means for initiating the combustion. As described previously, an alternate fuel (such as alcohol) can be supplied to nozzle 22 to start the device. The alcohol is atomized and ignited. The combustion is then allowed to continue until the combustion chamber is well heated and stable combustion exists. At a suitable point, glycerin is phased in and alcohol is phased out. The combustion then continues using glycerin as the only fuel.

Another alternative is to start the device on a mixture of glycerin and alternate fuel, then shift the mixture to glycerin. As for the previously described embodiments, a water purging system is preferably provided so that the lines can be cleaned after the combustion cycle is completed. In addition, any of the features of the embodiment of FIGS. 1-3 can be combined with the embodiment of FIGS. 7-12.

The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.

Claims

1. A method for burning glycerin, comprising: a. providing a combustion chamber housing having a mounting wall on a first end and a choke wall on a second end opposite said first end;b. providing a burner attached to said mounting wall and directed toward said choke wall, said burner including a central axis;c. said burner including, i. a nozzle,ii. wherein said nozzle includes a target surface,iii. wherein said nozzle includes an orifice directed toward said target surface,iv. wherein said nozzle includes a conduit for carrying said glycerin toward said orifice;v. wherein said nozzle includes at least one swirl channel for mixing air into said glycerin traveling down said conduit before said glycerin is ejected through said orifice;d. said burner including a turbulator surrounding said nozzle, said turbulator including, i. a cylindrical housing centered on said central axis, with a gap between said cylindrical housing and said nozzle,ii. a plurality of radially-spaced vanes within said gap between said cylindrical housing and said nozzle, wherein each of said vanes is angularly offset from said central axis so that said plurality of vanes forces air flowing through said turbulator housing to rotate;e. providing pressurized glycerin to said conduit in said nozzle;f. providing pressurized air to said swirl channels within said nozzle, so that a mixture of pressurized glycerin and air is forcefully ejected through said orifice and impacts said target surface, thereby atomizing said mixture;g. providing pressurized air to said turbulator, so that said pressurized air flows through said turbulator, with said turbulator causing said air to rotate as it flows past said nozzle, creating a swirling, atomized mixture of glycerin and air within said combustion chamber housing;h. igniting said atomized mixture of glycerin and air within said combustion chamber housing, so that said mixture combusts and converts into combustion products; andi. providing a choke outlet in said choke wall, with said choke outlet being sized to restrict the flow of said combustion products out of said combustion chamber housing in order to reduce the combustion speed of said mixture of glycerin and air below the flame propagation speed of said mixture.

2. A method for burning glycerin as recited in claim 1, further comprising: a. providing a source of alternate fuel to said conduit in said nozzle;b. prior to providing said pressurized glycerin to said conduit, providing said alternate fuel to said conduit in order to create an atomized mixture of said alternate fuel and air within said combustion chamber housing;c. igniting said atomized mixture of alternate fuel and air;d. continuing to burn said alternate fuel and air for a time period sufficient to produce stable combustion within said combustion chamber housing; ande. thereafter switching said alternate fuel to said glycerin so that said mixture within said combustion chamber housing transitions to glycerin and air while combustion continues within said combustion chamber housing.

3. A method for burning glycerin as recited in claim 1, further comprising: a. providing a source of alternate fuel to said conduit in said nozzle;b. prior to providing said pressurized glycerin to said conduit, providing a mixture of said alternate fuel and said glycerin to said conduit in order to create an atomized mixture of said alternate fuel, said glycerin, and air within said combustion chamber housing;c. igniting said atomized mixture of alternate fuel, glycerin, and air;d. continuing to burn said alternate fuel, glycerin, and air for a time period sufficient to produce stable combustion within said combustion chamber housing; ande. thereafter switching off said alternate fuel so that said mixture within said combustion chamber housing transitions to glycerin and air while combustion continues within said combustion chamber housing.

4. A method for burning glycerin as recited in claim 1, further comprising: a. shutting off said pressurized glycerin to said conduit in order to terminate said combustion; andb. providing a source of water to said conduit in said nozzle in order to flush said glycerin out of said nozzle.

5. A method for burning glycerin as recited in claim 1, wherein: a. said combustion chamber housing is cylindrical; andb. said choke outlet has a circular cross section.

6. A method for burning glycerin as recited in claim 2, wherein: a. said combustion chamber housing is cylindrical; andb. said choke outlet has a circular cross section.

7. A method for burning glycerin as recited in claim 3, wherein: a. said combustion chamber housing is cylindrical; andb. said choke outlet has a circular cross section.

8. A method for burning glycerin as recited in claim 1, wherein said nozzle includes multiple swirl channels for mixing air into said glycerin traveling down said conduit before said glycerin is ejected through said orifice.

9. A method for burning glycerin as recited in claim 2, further comprising: a. shutting off said pressurized glycerin to said conduit in order to terminate said combustion; andb. providing a source of water to said conduit in said nozzle in order to flush said glycerin out of said nozzle.

10. A method for burning glycerin as recited in claim 3, further comprising: a. shutting off said pressurized glycerin to said conduit in order to terminate said combustion; andb. providing a source of water to said conduit in said nozzle in order to flush said glycerin out of said nozzle.

11. A method for burning glycerin, comprising: a. providing a combustion chamber housing having a burner inlet on a first end and a choke outlet on a second end opposite said first end;b. providing a burner mounted to said combustion chamber housing proximate said burner inlet, said burner being directed toward said choke outlet;c. said burner including, i. an impingement nozzle with an orifice directing a pressurized stream against a target surface,ii. wherein said nozzle includes a conduit for carrying said glycerin toward said orifice;d. said burner including a turbulator surrounding said nozzle, said turbulator including, i. a cylindrical housing centered on said central axis, with a gap between said cylindrical housing and said nozzle,ii. a plurality of radially-spaced vanes within said gap between said cylindrical housing and said nozzle, wherein each of said vanes is angularly offset from said central axis so that said plurality of vanes forces air flowing through said turbulator housing to rotate;e. providing pressurized glycerin to said conduit in said nozzle, so that said pressurized glycerin is forcefully ejected through said orifice and impacts said target surface, thereby atomizing said glycerin;f. providing pressurized air to said turbulator, so that said pressurized air flows through said turbulator, with said turbulator causing said air to rotate as it flows past said nozzle, creating a swirling, atomized mixture of glycerin and air within said combustion chamber housing;g. igniting said atomized mixture of glycerin and air within said combustion chamber housing, so that said mixture combusts and converts into combustion products; andh. wherein said choke outlet is sized to restrict the flow of said combustion products out of said combustion chamber housing in order to reduce the combustion speed of said mixture of glycerin and air below the flame propagation speed of said mixture.

12. A method for burning glycerin as recited in claim 11, further comprising: a. providing a source of alternate fuel to said conduit in said nozzle;b. prior to providing said pressurized glycerin to said conduit, providing said alternate fuel to said conduit in order to create an atomized mixture of said alternate fuel and air within said combustion chamber housing;c. igniting said atomized mixture of alternate fuel and air;d. continuing to burn said alternate fuel and air for a time period sufficient to produce stable combustion within said combustion chamber housing; ande. thereafter switching said alternate fuel to said glycerin so that said mixture within said combustion chamber housing transitions to glycerin and air while combustion continues within said combustion chamber housing.

13. A method for burning glycerin as recited in claim 11, further comprising: a. providing a source of alternate fuel to said conduit in said nozzle;b. prior to providing said pressurized glycerin to said conduit, providing a mixture of said alternate fuel and said glycerin to said conduit in order to create an atomized mixture of said alternate fuel, said glycerin, and air within said combustion chamber housing;c. igniting said atomized mixture of alternate fuel, glycerin, and air;d. continuing to burn said alternate fuel, glycerin, and air for a time period sufficient to produce stable combustion within said combustion chamber housing; ande. thereafter switching off said alternate fuel so that said mixture within said combustion chamber housing transitions to glycerin and air while combustion continues within said combustion chamber housing.

14. A method for burning glycerin as recited in claim 11, further comprising: a. shutting off said pressurized glycerin to said conduit in order to terminate said combustion; andb. providing a source of water to said conduit in said nozzle in order to flush said glycerin out of said nozzle.

15. A method for burning glycerin as recited in claim 11, wherein: a. said combustion chamber housing is cylindrical; andb. said choke outlet has a circular cross section.

16. A method for burning glycerin as recited in claim 12, wherein: a. said combustion chamber housing is cylindrical; andb. said choke outlet has a circular cross section.

17. A method for burning glycerin as recited in claim 13, wherein: a. said combustion chamber housing is cylindrical; andb. said choke outlet has a circular cross section.

18. A method for burning glycerin as recited in claim 11, wherein said nozzle includes multiple swirl channels for mixing air into said glycerin traveling down said conduit before said glycerin is ejected through said orifice.

19. A method for burning glycerin as recited in claim 12, further comprising: a. shutting off said pressurized glycerin to said conduit in order to terminate said combustion; andb. providing a source of water to said conduit in said nozzle in order to flush said glycerin out of said nozzle.

20. A method for burning glycerin as recited in claim 13, further comprising: a. shutting off said pressurized glycerin to said conduit in order to terminate said combustion; andb. providing a source of water to said conduit in said nozzle in order to flush said glycerin out of said nozzle.