Liquid fuel industrial burner

Abstract

A liquid fuel burner comprising a burner tip outputs a thin ring of oil that may be more easily atomized by the flow of atomizing oxidant at lower pressures. The liquid fuel burner comprises a fuel conduit and an atomizing oxidant conduit coaxial about the fuel conduit. The fuel conduit and atomizing oxidant conduit output fuel and oxidant into a furnace through the burner tip. The burner tip includes a central dispersion head in the output end of the fuel conduit which operates to fan the liquid fuel oil outward into a thin fan shaped ring that then is atomized by the surrounding flow of high velocity oxidant.

Description

FIELD OF THE INVENTION

[0001] The present invention relates generally to industrial burners and more specifically to liquid fuel burners that atomize and burn liquid fuel for industrial applications.

BACKGROUND OF THE INVENTION

[0002] In conventional liquid fuel burners, liquid fuel such as oil is atomized by the combination of (1) either a single liquid fuel jet or multiple discrete liquid fuel jets and (2) a surrounding high velocity stream of atomizing oxidant such as air or oxygen. The high velocity oxidant causes the liquid-fuel to break up into small droplets suitable for combustion. Examples of single oil jet configurations are disclosed in Joshi et al., U.S. Pat. No. 5,567,141 and Joshi et al., U.S. Pat. No. 5,251,823. An example of a multiple discrete oil jet configuration is disclosed in Slavejkov, U.S. Pat. No. 5,547,368.

[0003] One of the disadvantages typical in prior art liquid fuel burners is that a relatively high atomizing oxidant pressure is necessary to effect atomization. This is particularly disadvantageous when oxygen (a term when used herein that includes oxygen enriched air) is used as the primary oxidant. In systems such as these, the on-site oxygen plant (not a cryogenic source) produces oxygen at an outlet pressure of only 10-15 PSIG which is typically insufficient to effect the desired atomization of oil. Booster compressors and increased system pressure are required to obtain desirable atomizing oxidant pressure levels, typically around 20 to 40 PSIG. This is undesirable for cost and practical reasons.

SUMMARY OF THE INVENTION

[0004] In view of the foregoing, it is a primary objective of the present invention to provide a liquid fuel burner that is capable of adequately atomizing oil or other liquid fuel at lower pressures for combustion.

[0005] In that regard, it is a further objective according to one embodiment of the present invention related to oxy-oil burners to provide a liquid fuel burning system that atomizes the liquid fuel at pressures obtained from the oxygen plant thereby eliminating or reducing the need for booster compressors.

[0006] In accordance with these and other objectives, the present invention is directed at a liquid fuel burner comprising a burner tip that outputs a thin ring of oil that may be more easily atomized by the flow of atomizing oxidant at lower pressures. The liquid fuel burner comprises a fuel conduit and an atomizing oxidant conduit coaxial about (one generally inside of the other) the fuel conduit. The fuel conduit and atomizing oxidant conduit output fuel and high velocity atomizing oxidant into a furnace through the burner tip. The burner tip includes a central dispersion head in the output end of the fuel conduit which acts to fan the liquid fuel oil outward into a thin fan shaped ring of oil that then is atomized by the surrounding flow of high velocity oxidant.

[0007] In greater detail, the burner tip includes a central liquid fuel nozzle mounted on the end of the liquid fuel conduit and an atomizing oxidant nozzle mounted on the end of the atomizing oxidant conduit. The liquid fuel nozzle is surrounded by an atomizing oxidant nozzle which outputs high velocity atomizing oxidant (or other suitable atomizing media such as compressible fluid, i.e. natural gas). The liquid fuel nozzle comprises a central stem having an enlarged dispersion head which diverts the flow of liquid fuel radially outwardly into a thin annular ring or film and into the stream of high velocity atomizing oxidant.

[0008] According to one embodiment dealing with an oxy-oil type industrial burner, the present invention is also directed toward an industrial burner system which bums oxygen with liquid fuel and that only needs the output pressure of the on-site oxygen plant as the operating pressure for atomizing the liquid fuel thereby eliminating or reducing the need for booster compressors.

[0009] Other objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:

[0011] FIG. 1 is a one quarter cross sectional side view of a oxygen-oil industrial burner in accordance with a preferred embodiment of the present invention.

[0012] FIG. 2 is an enlarged cross section of the burner tip for the burner illustrated in FIG. 1.

[0013] FIG. 3 is a schematic of the burner of FIG. 1 arranged in a system according to a preferred embodiment of the present invention.

[0014] FIG. 4 is a cross sectional side view of an oil only industrial burner in accordance with another preferred embodiment of the present invention.

[0015] FIG. 5 is an enlarged cross section of the burner tip for the burner illustrated in FIG. 4.

[0016] FIG. 6 is a fragmented partial cross sectional side view of a hot air liquid fuel industrial burner in accordance with another preferred embodiment of the present invention.

[0017] FIG. 7 is an enlarged cross section of the burner tip for the burner illustrated in FIG. 6.

[0018] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An oxygen-oil industrial burner 20 is illustrated in FIG. 1 in accordance with a preferred embodiment of the present invention that is adapted to atomize and combust oil or other suitable liquid fuel in a tube or furnace for heating in a variety of industrial applications. This particular type of burner 20 illustrated in FIG. 1 would typically be mounted to a burner tube (not shown).

[0020] Except for the novel burner tip 22 which will be described later, the rest of the burner 20 is rather conventional in several respects. The burner comprises a tubular liquid fuel conduit 24 having a liquid fuel inlet port 26 for receiving liquid fuel and an outlet end 28 for dispensing oil or other such suitable liquid fuel for combustion. The liquid fuel conduit 24 is coaxial and generally concentric within an atomizing oxidant conduit 30 forming an annular chamber 32 that provides a flow path for high velocity atomizing oxidant or other suitable atomizing media such as compressed fluid, e.g. natural gas. The atomizing conduit 30 has an inlet port 34 for receiving pressurized oxidant and an outlet end 36 arranged adjacent to and in substantially the same plane as the fuel outlet end 28, and is configured to form a venturi 38 or atomization region such that high velocity atomizing oxidant causes sprayed liquid-fuel to break up into small droplets suitable for combustion. The position of the fuel outlet end 28 may be adjusted over a range and controlled axially relative to the atomizing outlet end 36 by a linear control mechanism 40 that in turn adjusts the configuration of the venturi 38 and therefore the characteristic of the atomizing oxidant flow and droplet size of atomized oil. This particular burner 20 also includes a combustion oxidant conduit 42 concentrically surrounding the fuel and atomizing conduits 24, 30 for conveying the large volume of combustion oxidant, which in this case is oxygen, to complete the combustion of atomized droplets of liquid fuel. The combustion oxidant conduit 42 has an inlet port 44 for receiving the oxidant and an outlet end 46 that outputs into the furnace tube (not shown) that carries the oxidant further for combustion.

[0021] In accordance with the present invention, and referring to FIGS. 1 and 2, the preferred embodiment includes a novel burner tip 22. The burner tip 22 is preferably a separate assembly of machined or formed components that are mounted to ends of coaxially disposed pipes 48, 50. O-Rings 51 may be arranged to provide a seal and prevent leakage between conduits. The pipes 48, 50 form the majority stretch of the liquid fuel and atomizing conduits 24, 30 while the burner tip 22 forms the respective ends 28, 36 of the conduits 24, 30. The burner tip 22 comprises a liquid fuel nozzle 54 disposed concentrically within a surrounding atomizing nozzle 56. The surrounding atomizing nozzle 56 comprises an outer sleeve having a converging end 58 that converges radially inward as it extends toward the downstream atomizing and combustion area. The atomizing nozzle 56 also includes angularly spaced, inward projecting locating ribs 62 which slidably engage the inner liquid fuel conduit 24 and center the liquid fuel conduit 24 therein. Flow passages 64 are defined between adjacent ribs to communicate the high velocity oxidant to the atomizing outlet end 36.

[0022] In a preferred embodiment, the liquid fuel nozzle 54 is a two piece assembly comprising a nozzle sleeve 66 and a nozzle stem 68 mounted into the nozzle sleeve 66, preferably via threads to allow for removal and replacement. The nozzle sleeve 66 comprises central through-hole 70 that includes a large diameter section 72 and a smaller diameter section 74 joined by a radially planar seat 76. The nozzle stem 68 comprises a smaller diameter partially threaded shank portion 78 mounted into the smaller diameter section 74 and an enlarged diameter tip portion 80. The nozzle stem 68 includes an axial passage 82 through the center of the stem 68 and cross holes 84 which communicate oil other liquid fuel from the fuel pipe 48 to an annular recess or collection chamber 86 formed in or between the nozzle stem 68 and/or nozzle sleeve 66.

[0023] At its end, the enlarged diameter tip section 80 also includes a central enlarged frusto-conical dispersion head 88 arranged in close spaced apart relationship to the fuel outlet end 38 of the fuel conduit 24. When the stem 68 is mounted into the nozzle sleeve 66 with a nut on the back side for securement, the enlarged diameter tip section 74 seats on the seat 76 to maintain this spaced apart relationship. The dispersion head has a conical surface 90 that in the illustrated embodiment expands radially outwardly toward the atomization and combustion area. The fuel outlet end 28 also includes a complementary conical surface 92 in parallel spaced relation to conical surface 90. Between the enlarged dispersion head 88 and the outlet end 38 is an annular orifice forming the outlet port 94 from which oil is dispersed with radial and axial components. The outlet port 94 is preferably continuous all the way around the dispersion head.

[0024] In operation, pressurized oil or other liquid fuel at preferably between about 1 PSIG and about 50 PSIG is received in the fuel inlet port 26 and travels to the conical outlet port 94 where it is dispersed by the enlarged dispersion head 88 into a thin, uniform ring of oil which includes both axial components and radial components. The atomizing oxidant travels through atomizing oxidant conduit 30 and intersects the thin and uniform ring of oil atomizing the oil into fine droplets suitable for combustion. Once atomized, the oil droplets are then combusted by oxidant, most of which is supplied from the outermost conduit, namely, the combustion oxidant conduit 42. It is an advantage that the configuration and production of a thin film or thin ring of oil that intersects the high velocity atomizing oxidant in the area of the venturi 38 reduces the atomizing oxidant pressure necessary to effect desired combustion. In fact, it has been found that the atomizing oxidant in conduit 30 may be at a pressure of between about 1 and about 15 PSIG, although higher atomizing oxidant pressures are certainly acceptable. This advantageously eliminates or reduces the need for booster compressors used in other burner systems associated with on site oxygen plants at the factory or other site at which the burner operates.

[0025] In this regard, an improved industrial burner system 95 incorporating the improved burner 20 is schematically illustrated in FIG. 3. The burner system 95 includes an oxygen plant 96 and an oil supply 97. The oxygen plant 96 separates oxygen from other components of atmospheric air and outputs oxygen at a pressure of between about 10 PSIG and about 15 PSIG to a combustion oxygen flow control train 98 and an atomizing oxygen flow control train 99. The combustion oxygen flow control train 98 controls oxygen flow rate to the combustion oxygen inlet port 44. The atomizing oxygen flow control train 99 controls oxygen flow rate to the atomizing oxygen inlet 34. The system further includes an oil flow control train 100 that controls the pressurized flow of oil to the fuel inlet port 26. Advantageously, no booster compressors are necessary to effect suitable atomization of the oil. Lower oxygen pressure may be used throughout the system both for atomization and combustion purposes.

[0026] Turning to the second and third embodiments of FIGS. 4-5 and FIGS. 6-7 respectively, similarly reference characters are used to designate similar and like function components (the numbers being increased by 100 or 200 for the second and third embodiments, respectively, for purposes of differentiation). The second embodiment illustrated in FIGS. 4-5 is an “oil only” industrial burner 120. The industrial burner 120 comprises a fuel conduit 124 having an inlet port 126 and an outlet end 128 and an atomizing oxidant 130 conduit having an inlet port (not shown) and an outlet end 136. In this embodiment, combustion oxidant does not travel through burner itself (except for the atomizing oxidant) but instead is otherwise introduced further downstream from the outlet ends 128, 136 in a combustion zone for mixing with combustion air and for formation of a flame having the desired length, shape, heat release rate and profile.

[0027] The novel burner tip 122 of the second embodiment is similar in many respects as the first embodiment having an outer sleeve/atomizing nozzle 156 and inner sleeve/fuel nozzle 166 disposed concentrically therein. A stem 168 is mounted into the center of the fuel nozzle 166 and includes the enlarged dispersion head 188 which disperses oil with radial and axial components into a thin ring of oil that is subsequently atomized by the high velocity atomizing oxidant expelled through the atomizing nozzle 156. A couple differences will be pointed out in this second embodiment. One difference is that an end plate 159 is mounted and welded onto the end of the atomizing nozzle 156. Another difference is that a threaded ring or nut 163 secures the stem 168 to the fuel nozzle 166. A third difference is that the locating ribs 162 are part of the fuel nozzle 166 not the atomizing nozzle 156 and project radially outwardly from the outer periphery surface of the fuel nozzle 166 to slidably engage the inner cylindrical surface of the atomizing nozzle. In any event, the burner tip 122 sprays oil into an annular ring which is more easily atomized at lower atomizing oxidant pressures.

[0028] The third embodiment of the present invention illustrated in FIGS. 6-7 takes the form of a “hot air” liquid fuel burner 220 which uses heated air as the oxidant (which is blown by a blower (not shown)). The industrial burner 220 comprises a fuel conduit 224 having an inlet port 226 and an outlet end 228, and an atomizing oxidant conduit 230 having an inlet port 234 and an outlet end 236. In this embodiment, combustion oxidant in the form of preheated air travels through burner 220 itself through a combustion oxidant conduit 242 coaxially surrounding and mounted via welding generally concentric about both the fuel conduit 224 and atomizing conduit 230. A mounting plate 243 is mounted directly on the combustion oxidant conduit 242 to facilitate mounting of the burner to a complimentary furnace surface. In this embodiment, combustion air is introduced immediately downstream from the outlet ends 228, 236 in a combustion zone in which combustion air and atomized oil mix and combust. The end of the combustion oxidant conduit 242 extends axially just beyond that of the burner tip 222.

[0029] The novel burner tip 222 of the third embodiment is similar in many respects as the first and second embodiments having an outer sleeve/atomizing nozzle 256 and inner sleeve/fuel nozzle 266 disposed concentrically therein. A stem 268 is mounted into the center of the fuel nozzle 266 and includes the enlarged dispersion head 288 which disperses oil with radial and axial components into a thin ring of oil that is subsequently atomized by the high velocity atomizing oxidant expelled through the atomizing nozzle 256. A couple differences will be pointed out in this third embodiment. One difference is that the fuel nozzle sleeve 266 is of two piece assembly including a first sleeve 271 screwed into a second sleeve 275 which includes a threaded stub end 279 that in turn screws internally into the fuel pipe. In this embodiment, the locating ribs 262 also project radially outward from the fuel nozzle sleeve 266. From the forgoing, it should be apparent that the locating ribs can be provided by the inner or outer sleeve depending upon the desired configuration. The locating ribs may also extend axially in a spiral or helical manner if desired.

[0030] The foregoing description of various preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

1. A liquid fuel industrial burner for burning liquid fuel and oxidant, comprising:

a liquid fuel conduit having a liquid fuel inlet for receiving pressurized liquid fuel and a first discharge end for discharging liquid fuel;

an atomizing media conduit surrounding the liquid fuel conduit having an atomizing media inlet for receiving pressurized atomizing media and a second discharge end for discharging atomizing media; and

a burner tip at the discharge ends of the of the liquid fuel conduit and the atomizing media conduit, the burner tip including a dispersion head arranged in the first discharge end forming an annular discharge orifice between the first discharge end and the dispersion head.

2. The liquid fuel industrial burner of claim 1 wherein the dispersion head has a conical deflecting surface at the annular discharge orifice, the conical deflecting surface adapted to impart radial components to discharged liquid fuel and direct discharged liquid fuel into the path of discharged atomized media for atomization of the liquid fuel.

3. The liquid fuel industrial burner of claim 1, further comprising a combustion oxidant conduit for receiving pressurized oxidant adapted to discharge oxidant downstream of the first and second discharge ends for completing stochiometric combustion of atomized liquid fuel.

4. The liquid fuel industrial burner of claim 1 wherein the first and second discharge ends lie in substantially the same plane such that during operation rapid expansion of atomizing media discharged through the second discharge end atomizes liquid fuel via the venturi effect.

5. A liquid fuel industrial burner for burning liquid fuel and oxidant, comprising:

an inner pipe for transmitting liquid fuel toward an atomization region;

an outer pipe coaxial about the inner pipe for transmitting atomizing media toward the atomization region;

a burner tip comprising a liquid fuel nozzle and an atomizing nozzle;

the liquid fuel nozzle mounted on an end of the inner pipe including (a) a nozzle sleeve and (b) a nozzle stem, the nozzle sleeve having a central through hole extending toward an annular first discharge end proximate the atomization region, the nozzle stem mounted into the through hole and having an enlarged dispersion head forming an annular discharge orifice between the dispersion head and the annular first discharge end, the dispersion head arranged and configured to form a thin ring of liquid fuel that includes radial and axial components;

the atomizing nozzle mounted on an end of the outer pipe coaxial about the liquid fuel nozzle adapted to output a atomizing flow of atomizing media through a second discharge end for atomizing said thin ring of liquid fuel.

6. the liquid fuel industrial burner of claim 5 wherein the dispersion head is frusto-conical having a conical surface substantially parallel to a conical surface of the annular discharge end.

7. The liquid fuel industrial burner of claim 6 wherein the nozzle stem is mounted into the nozzle sleeve, the stem including an internal passage fluidically connecting the interior of the inner pipe to an internal annular chamber formed between nozzle stem and the nozzle sleeve proximate the dispersion head.

8. The liquid fuel industrial burner of claim 6 wherein the respective discharge ends of the atomizing nozzle and the liquid fuel nozzle lie in substantially the same plane such that during operation rapid expansion of atomizing media discharged through the second discharge end atomizes liquid fuel via the venturi effect.

9. The liquid fuel industrial burner of claim 6 wherein the burner tip includes a plurality of radially projecting ribs between the inner surface of the atomizing nozzle and the outer surface of the liquid fuel nozzle centering the inner pipe inside of the outer pipe, flow channels being formed between adjacent ribs for communicating atomizing media therethrough.

10. The liquid fuel industrial burner of claim 9 wherein the inner pipe is movable along an axis relative to the outer pipe to adjust the relative positions of the atomizing nozzle and liquid fuel nozzle and thereby the characteristic of the burner tip, further comprising a control mechanism adapted for adjusting the position of the inner pipe.

11. The liquid fuel industrial burner of claim 6 wherein the second discharge end converges radially inward toward the atomization region, and wherein the head includes a diversion surface along the discharge orifice that diverges radially outward as in extends toward the atomization region.

12. The liquid fuel industrial burner of claim 6 wherein the nozzle sleeve is connected to the inner pipe via threads, further comprising a ring gasket arranged between the inner pipe and the nozzle sleeve for preventing liquid fuel leakage therebetween.

13. The liquid fuel industrial burner of claim 6 wherein the liquid fuel industrial burner is an oxy-oil industrial burner.

14. The liquid fuel industrial burner of claim 6 wherein the liquid fuel industrial burner is an oil only industrial burner.

15. The liquid fuel industrial burner of claim 6 wherein the liquid fuel industrial burner is a preheated air-oil burner wherein the air is preheaded.

16. The liquid fuel industrial burner of claim 6, further comprising a combustion oxidant conduit coaxial about the inner and outer pipes for receiving pressurized oxidant adapted to direct oxidant toward the first and second discharge ends for completing combustion of atomized liquid fuel.

17. An oxy-liquid fuel industrial burner system for burning liquid fuel and oxygen, comprising:

a liquid fuel supply;

a liquid fuel flow control train connected to the liquid fuel supply adapted to control a pressurized flow of liquid fuel

an oxygen plant producing a pressurized source of oxygen;

a combustion oxygen flow control train connected to the oxygen plant adapted to control a pressurized flow of oxygen;

an atomizing oxygen flow control train connected to the oxygen plant in parallel with the combustion oxygen flow control train adapted to control a pressured flow of atomizing oxygen; and

a liquid fuel industrial burner comprising:

(a) a liquid fuel conduit having a liquid fuel inlet connected to the liquid fuel flow control train for receiving pressurized liquid fuel and a first discharge end for discharging liquid fuel;

(b) an atomizing oxidant conduit surrounding the liquid fuel conduit having an atomizing oxidant inlet connected to the atomizing oxygen flow control train for receiving pressurized oxidant and a second discharge end for discharging atomizing oxidant;

(c) a burner tip at the discharge ends of the of the liquid fuel conduit and the atomizing oxidant conduit, the burner tip including a dispersion head arranged in the first discharge end forming an annular discharge orifice between the first discharge end and the dispersion head; and

(d) a combustion oxidant conduit connected to the combustion oxygen flow control train for receiving pressurized oxidant adapted to discharge oxidant downstream of the first and second discharge ends at a selected location for completing stochiometric combustion of atomized liquid fuel.

18. The oxy-liquid fuel industrial burner of claim 17 wherein the oxygen plant produces oxygen at a pressure of between about 10 and about 15 psi, wherein no booster compressor is used in the atomizing oxidant flow.

19. A liquid fuel industrial burner, comprising:

a liquid fuel conduit connected to a supply of liquid fuel;

an atomizing media conduit coaxial about the liquid fuel conduit connected to a source of pressurized atomizing media;

a burner tip at ends of the liquid fuel conduit and atomizing oxidant conduit comprising a fuel nozzle for the liquid fuel conduit and an atomizing nozzle for the atomizing media conduit coaxial about the fuel nozzle forming a venturi about the fuel nozzle, the fuel nozzle having an outlet orifice with an enlarged dispersion head therein imparting axial and radial components to liquid fuel exiting the outlet orifice and intersecting atomizing media flowing through the venturi.

20. The liquid fuel industrial burner of claim 19 wherein the fuel nozzle is a multiple piece assembly comprising a nozzle stem mounted into a nozzle sleeve, the stem providing the enlarged dispersion head.

21. The liquid fuel industrial burner of claim 19, further comprising a combustion oxidant conduit coaxial about the liquid fuel and atomizing conduits connected to a source of pressurized oxidant, the combustion oxidant conduit adapted to direct oxidant toward the first and second discharge ends for completing combustion of atomized liquid fuel.

22. The liquid fuel industrial burner of claim 19 wherein the enlarged dispersion head is frusto-conical.