Title of Invention

A STAGED OXY-FUEL BURNER FOR PRODUCING A GENERALLY FLAT LUMINOUS FLAME , A STAGED OXY-FUEL COMBUSTOR SYSTEM AND A METHOD OF PRODUCING A LOW NOx OXY-FUEL FLAME FOR HEATING A FURNACE TO AN ELEVATED TEMPERATURE

Abstract A STAGED OXY-FUEL BURNER FOR PRODUCING A GENERALLY LUMINOUS FLAME , A STAGED OXY-FUEL COMBUSTOR SYETEM ANSD OF METHOD OF PRODUCTING NOX-FUELFLAME FOR HESTING A FURNACE TO AN ELEVATED TEMPERATURE
Full Text

The present invent.ton p^ri.'.ains to oxy-fuel methods and devices for produciiiij elevated temperatures in industrial melting furnaces tor auch diverse products as metals, glass, ceramic materials and the like.
BACKGROUND OF THE INVENTION
Increased air quality regulations and strong market competition are forcing glass manufacturers to change the process of making glass. While post-combustion flue gas treatment techniques can solve the problem of pollution, they usually involve significant

capital and operating costs making it more difficult for process'improvements by the glaat* manufacturers to be economical.
*■»
One cost effective method for controlling emissions as well as reducing capital, requirements is the implementation of oxy-fuel gl^eu melting technology. Use of oxy-fuel In glauB melting eliminates nitrogen in the melting ptooess and reduces NOx and particulate emissions to below the levels set by the Environmental Protection Agency (EPA) . In addition, oxy-fuel combustion reduces carbon diokide emissions and brings numerous other benefits ranging from increased production capacity to savings in the amount of batch chemicals r&efuired.
Use of oxy-fuel burhers in glass melting permits the burner designer to achieve varying flame momentum, glass melt coverage 4hd flame radiation characteristics. Different burnern produce different levels of NOx ^n furnaces where nitrogen is present from air leakage, low-purity oxygen supplied from a vacuum swing or pressure swing adsorption unit, nitrogen in the fuel, or nitrogen contained in the batch chemicals. Non-compliance with NOx emission standards, rules and regulations can lead to very large penalties and fines, substantial capital expenditure for clean-up technology, or require the purchase of NOx credits.
Conventional oxy-£ut3l burners used in glass melting have a significant problem in that the flame produced by the burner is relatively narrow and short providing very limited coverage of: the molten glass in the furnace. Since such flamea are at very high

temperatures, areas immediate ly Uftdef those flames can easily overheat causing unde»lj:e4 wid» effects such as reboiling of the glass leading!to tlu» formation of scum on the melt surface. The scutn-on the melt surface is usually associated with poor h«t*at transfer and inefficient melting operations. l'o:t laome high quality glasses such as television panal ami float glass, the glass quality can be signif lastly a effected by the presence of scum in the furnace.
1 Another problem with conventional oxy fuel
burners is related to the relatively .low luminosity of
an oxygen-natural gas flame, Radial Inn from such
flames comes from the combustion pi: Mil lets, water vapor
and carbon dioxide, radiating predominantly wavelengths
which are absorbed by the surlace of the glass melt.
This adversely affects the oveirall heat transfer as
this surface absorbed heat is re-radiated not only
where it needs to go, i.e. down into the lower layers
of the -glass melt, but al£o back up towards the furnace
crown. In contrast, luminous flames radiate a
significant portion of radiation in the wavelengths
that penetrate glass, thus making it easier to deliver
heat to the lower layers of the malt,
Another problem associated With the use of oxy-fuel burners is that they operate at relatively high momentum, i.e. flame velocity, which can increase volatilization of volatile batch components and increase particulate emissions. Such burners can also increase refractory corrosion due to higher refractory temperatures and higher volatile concentrations in the 1 gas phase. U.S. Patents 5,199,866; 5,256,058; and 5,346/390 disclose methods and devioee for producing luminous flames at lowered flamed morrlehtums. However,

even with the advent of the patented burners and processes, flame radiation, fleime coVferage and N0X caused by leaky furnaces have riot beSft fully addressed.
U.S. Patent 4,927,397 discloses a gas-injection lance, burner which producer a flame by having an elongated fuel jet which entrains air from a port above the fuel jet intern0cting mi elongated gas (oxygen) jet inside a furnace to produce a flame flattening effect.
SUMMARY OF THIS INVENTION
In order to overcome problems with prior art burners and combustion systouts and to address the problems of flame radiation, flame coverage and NOx in leaky furnaces, it has been discovered that a staged flat flame combustion system and burner wherein a fuel rich flattened flame overlies %\ fuel lean highly radiative flame with the composite* flame shaped in the form of an elongated or generally flat rectangle, flame luminosity is dramatically increase
passages is an elongated oxidizer passage which is adapted to introduce oxygen Underneath the fuel-rich flame produced by the upper portion of the burner to thus achieve the fuel-rich frame overlying the fuel-lean flame. According to the invention, a precombustor or burner block can be disponed of\ the flame end of the burner to further enhance operating characteristics of the burner. The precombustor or burner block contains an oxidizer passage which is of: a complementary shape and generally parallel to the oxy-fuel flame passage to achieve the same fuel-rich oxy-£uel flame overlying a fuel-lean highly radiative flame.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic perspective view of an apparatus according to the present invention.
Figure 2 is an enlarged front elevational view of the burner of Figure 1Figure 3 is a schematic vlttw representing a horizontal cross-section through the passages of the precombustor of Figure 1.
Figure 4 is a vertical uroBB-section of the passages of the precombustor of Figure 1.
Figure 5 is a perspective view illustrating the process of the present invent Loft *
? Figure 6 is a schematic vertical cross-section of a combustion system according to the present
invention.

Figure 7 is a plot of flame velocity against staging for* an apparatus accnnrcUnif to the present invention.
Figure 8 is plot of flume velocity against staging for an alternate embodiment: of the present invention.
Figure 9 is a plot of lUmp*. velocity against
staging for another embodiment: of the present
invention. '
Figure 10 is a plot of t la* measured NO emissions against percent oxygen flfc&Gfing for the method and apparatus of the present inv^ulIon.
Figure 11 is a plot of normalized NO emissions against percent oxygen staging from ^he data of Figure 10.
Figure 12 is a plot of normalized NO emissions against percent oxygen staging for a variety of burner operating conditions.
Figure 13 is a schematic top plan view of a glass furnace heated according to the prior art.
Figure 14 is a schematic plan view of a glass melting furnace employing a fouriuu: according to the present invention.
Figure 15a is a bar graph depicting relative crown temperatures for conventional oxy-fuel burners

and staged combustion according to the present invention, •
Figure 15b is a bar graph of relative melt temperatures for conventional oxy-fuel burner and staged oxy-fuel burners according to the present invention.
DETAILED DESCRIPTION OF THE! INVENTION
The present invention, in directed to a method and apparatus that is an improvement over the method and apparatus shown and described in co-pending U.S. application Serial No, 03/334,308 Elled November 4, 1994, the specification of which let Incorporated herein by reference. The present invention is an improvement in the sense that it employs the Invention of the copending application in a staged. conbustion system and
process.
!
The following is a list of: terms and assumptions used in describing thus invention:
Oxygen is taken to mean an oxidizer gas with" greater than 30% oxygen, preferably HO to 100% oxygen.
Fuel is taken to mu&n any gaseous hydrocarbon fuel. Natural gas flames are usually not luminous, so the emphasis in the following detailed description is on natural gas as a fuel, hoWever, i£ is reasonable to expect that the present invention increases flame luminosity of other gaseous fuels.
i



shape, having a shape complemen,tary to the shape of the natural gas* passage 16 of burttar 12 Staging oxygen is conducted through passage 22 &t\& out through a passage 24 in the burner block 14. Th« flat Ufa,I gas and the combustion oxygen combine to prodiK?* a flame at a discharge end 17 of natural gn» p&Bfc&g© 16. Staging oxygen exits passage 24 at th* sain® face 21 of burner block 14. The fuel rich oxy-fuel flame combines witrh the staging oxygen flow after being discharged from discharge end 21 of burner block 14,
Figure 2 shows the f'tisch&tge nozzle end of the burner 12 wherein the conduit 16 delivers natural gas and the passage between the conduit 16 and the outer conduit 18 is used to de.livf.vt: oxygen for combustion with the natural gas•
Figure 3 is a top sectional Bchematic view of the passage for both the flam# pjrcMftiaed by the burner 12 and the staging oxygen illustrating the angle of divergence for these passages, Tim emgle of divergence is shown as the half angle (a/3) tioinfl equal to or less than 15%.
Figure 4 is a vertical smntion through the burner block 14 showing the half aiitjle (S/2 being equal to or less than 10°) for the f I tune and oxygenjpassages 20, 22 respectively.
Figure 6 shows th© invent J OH in schematic form which figure can be used to df»f»at:lbe the process , of the invention witph a burmti fclook. As shown in Figure 6, natural gas and combustion oxygen are combined to produce a fuel-rich flame 30. Staging

oxygen is introduced beneath fclie jiiej rich flame to produce a highly radiative fu^l-lean flame 32. Circulation patterns are shown by tins arrows 31, 33 respectively for the fuel-riftfr flame and the fuel-lean flame. As shown in Figure 6 «, highly radiated fuel-lean flame can be produced over a furnace load 34 which can be molten glass as will hereih^fter be more fully discussed. According to the present invention, staging oxygen is conducted to the apparatus by diverting a portion of the combustion oicygen from the burner used to produce the oxy-fuel fuel-rich flame. The amount of oxygen diversion is referred to as percent staging as will hereinafter be more fully described.
According to the preaent: invention, a staged combustion method and apparatus pioduces lower NOx/ higher flame luminosity and better flame coverage than is currently available with oxy-fuel burners. The
0
method and apparatus of the present invention can produce flames with more intense radiation directed toward the furnace load, e«g* glass, aluminum, steel, etc, than towards the crown of: the furnace. This in turn should improve process ajfficiendy, increase the life of furnace crown refractories and improve product quality.
The natural gas surrounded by oxygen permits the flame to pass through the prsoombuator without damaging the walls. The reaot;#ttit lioiRtfle velocities should be kept below 600 ft. per Hiac-Qnd and should be identical for both natural gaji and oxygen to provide optimum results. A discussion of the benefits of oxy-fuel combustion by controlling reaotant velocities can be obtained from U.S. Patent ft#19«fB66; 5,256,058; and

5,346,390 the specifications of which are incorporated herein by reference.
Staging oxygen velocity is, in general, lower or similar to the flame velocity to allow formation of * a continuous higher-radiatiati flairtfe Zone directed towards the furnace load. The flaw® having a higher velocity entrains the lower velocity oxygen producing a fuel-lean flame zone as illustrated-in Figure 6, This is in contrast to the widely used high-velocity staging
where an oxygen jet creates a localised high-
i
temperature flame zone which ueually reduces the overall flame length. The resulting delayed-mixing flame of the present invention, having a fuel-rich zone on the top and a fuel-lean zone on the bottom, is much longer, produces lower NOx and radiates more towards the furnace load than a non-*atagin# flame.
According to the present invention where a precombustor is used, this being the preferred embodiment, a range of precombustor diverging angles is ■ used to control the flame. The half angles for the nozzle and the horizontal plane ate preferably equal to or less than 15°. The precotnbuetoi" in used to enable flame acceleration as the volume of: reectant, i.e. fuel and oxygen, increases due to temperature increase from combustion. The gases expand end J!lame velocity reaches maximum for the lowest angle. On the other hand, a divergence half angle of 1W° in the combustor compensates for gas expansion fttid produces minimum acceleration. The preferred f I Situs velocities at the exit end 21 of the burner block 14 are between 30 and 60 ft. per second as the flame exiattf the prepombustor 14. Flame velocities below 30 ft, per second are too

low to avoid lofting of the flame and allow for proper flame momentum in a high-temperature furnace. Flame velocity above 60 ft. per second begins to show increased turbulence which can reduce flame length and luminosity and increase the production of NOx-
A straight through or 0° turieaoombustor divergence angle is the best choice for burners firing at low rates, e.g. 1 to 3 Btu/hr. Referring to Figure 7, oxygen staging permits control of flame velocity to maintain flame length luminosity arid low turbulence or mixing for low NOx operation. fat higher firing rates up to 6 million Btu/hr, a 10° preoombuator divergence angle is recommended. The 10° ttivftt'tfertce angle allows for gas expansion and reduces ttatn^ acceleration inside the precombustor. Figure 8 illustrate® the preferred operating ranges where the precombustor has a 10° diverging angle. A 15° precombustttr diverging angle will produce optimum flame velocity for firing rates up to 12 million Btu/hr. Figure $ shown the preferred operating range for the system of I lie present invention where the precombustor has a IS0 diverging angle. However, the flame velocity at firltW rates equal to or less than 3 million Btu/hr. may b© too low causing improper flame shape (lofting). TlHw affect will vary depending upon furnace temperature, i.e. the temperature difference between the flame and furnace gases. The higher this difference ia, the more flame lofting will occur. Flame looting is* the phenomena that occurs when due to improper operation of the burner, the flame instead of extending generally parallel to the load rises toward the ceiling or crown of the furnace.

Set forth in Table 1 belqw are design parameters for a staged combustion systems according to, the present invention.

(
ftfel / total oxygen] actual JUel f total \txygen\ theoretical
Observing the design pat mml&rs set forth in Table I will lead to effective low NO}( combustion systems with luminous flames, Figure* 7, 8 and 9 represent performance of preferred embodiments of the present invention. The flam« velooities would change if the design parameters ar@ tihariij&d $uch as fuel nozzle width, w/h ratio, and twecotiibUNtor length.
High-temperature tvats Kst t\\m staged-combustion oxygen-natural gaa tournar produced according to the present invention wer# yomluat^ci in a combustion laboratory furnace. The testii were to determine the

effects of oxygen staging ori W0X fttnitl&ions, flame length and luminosity. Temperature of the furnace was maintained at about 2300° F whil© measurements were made at different staging level®.
Most of the NOx measurement® were made for a fixed firing rate, overall etoichiometry, and air entrainment in the following order:
1. Base case, no staging - all oxygen through the precombustor.
2. 75% oxygen staging - 26% oxygen to the precombustor.
3. 40% oxygen staging - 60% oxygen to the precombustor.
4. Base case, no stagrittti all oxygen through the precombustor*
The first and last toad! tiff & were taken under identical conditions to check the reproducibility of the data. An example of a d*t$ s$tt: i«i shown in Figures 10 and 11 where NO was reduced tip to 40% with oxygen staging. The same data set but with normalizsed NO emissions is shown in Figure XX* 't'h« data normalization should allow oattip#r:lMoli of NO emissions at various operating condition** -
Another more extenotve *«(: off data using different firing rates, stoiohiometry and furnace temperature is shown in Tabln II below.



formation, came mostly from Curnaise leaks and, in small quantities,•from natural gas. From Table II, it can be seen that the experiments whereifi staging was employed, either at 25 or 60% oxygen through the precombustor,
had a significant reduction in NO.
I
Table III below setn foVih the results of a further series of measurement Ml whw:t«in a controlled amount of air, e.g. 5000 scfh at *>0° I*' was introduced into the furnace.

From Table III, it can be seen thefonygen staging was effective to reduce the NO emissions over operation when no staging was employed. Figure .12 graphically illustrates the efficiency ot lowering NO emissions with staged combustion. As seen from Figure 12, the NO reduction is about 40% compared to the non-staged operation for any particular set of burner operating parameters with or without additional air.
After the laboratory testa were conducted, a staged oxygen combustion system according to the present invention was installed in ft glass melting furnace operating at an average temperature of about

2800° F at a constant pull r«t« of about 150 tons per day of glass- The test involved replacing one conventional oxy-fuel burner having a relatively short and narrow visible flame, low flaifle luminosity and relatively high flame momentum With a new stage
combustion burner having a lons/3/wid© flame, high
iff**' ' *
flame luminosity and much lowejr flam© momentum. Figure
13 shows the glass furnace 40 With the conventional
burners 42, 44, 46, 48/50, 55!* 36 and 58. For the
purposes of the present invention* burner 42 which
utilizes 15% of the fuel utilised in the entire furnace
was replaced with a combustion pysl:em according to the
present invention. Burner 42 \%\ nimr the pull end 60
of the furnace 40.
The objectives of the teut: were to:
f
1. observe the changes in furnace temperature
by observing thermocouples in the f'tmmoe crown and in the bottom of the glass melt;
2. determine the increase in fuel efficiency, i.e. potential fuel savings, it the temperature readings increased;
3. observe if improved flam& characteristics including coverage, high luminosity, and lower momentum affect the scum blanket pretfeftt on the glass surface.
The scum blanket is shown as $2 in Figure 13 and extends almost to the position Of th* Opposed firing burners 42, 58 in the furnace 40, '.the portion of Figure 13 indicated as batch indicates the position of batch materials that are unreached Which batch line
0

extends to the position of burner 44 . The use of oxy-fuel burners in a glass furnace can oauae localized heating Immediately under the flumen Which results in surface reboiling of the glas© leading to scum formation. The scum on the glam$ eurtaup is usually associated with poor overall heat fcratiet'er and inefficient melting operations. For pome high quality glasses such as television panelfl aru:| float glass, the glass quality is reduced significantly by the presence of scum on the surface of the welt. Localized glass surface overheating also affect^ Volatilization of the batch chemicals and emissions of: pa? Li emulates. It has been shown that an increase in glass mi? lace 1 temperature of 150° C can more than double sodium sulfate dust emissions and al&o ityo:t.ftflf»io corrosion rate of furnace refractories when the £\N"Xmwn has been converted to oxy-fuel firing.
According to the present invention, as shown in Figure 14, a burner system 10 was installed in place of the burner 42 in furnace 40, As shown in Figure 15a the average furnace crown temperature was higher when using staged combustion oxy-fuel firing according to the present invention. As showh in Figure 16b the average melt bottom temperature was much higher during staged combustion according to the present invention as opposed to conventional oxy-fuel he^tillQ' of the furnace. The temperature increase^ (significantly when a staged combustion burner was installed, It was also observed that the total furnace fuel consumption, i.e. firing rate trend, was reduced 24 hre. after the burner according to the present invention wae installed. The reasons for fuel flow reduction was th® furnace operators concern that the overall furnace temperatures

were getting too high. Even With the lower firing rate, the temperature in,the sipne of. the furnace under the burner 10 was still higher than the base line operation. The flame radiation mftmct was confirmed when the burner was pulled out of the furnace and the conventional burner reinstalled, thu© producing a sharp temperature drop. Fuel concumption was then increased to prevent the furnace from cooling down.
As can be seen from ^igUr^ 14, utilizing the burner according to the pre^rtit ihv^jrUion not only-increased temperature, but moVed tha ecum line back toward the batch end of the furnao© to a location approximately at burner 44 and pushed the batch line back to approximately the location of burner 46. Both conditions which would be conducive to producing high quality glass such as necessary for television panels, and float glass. In actual nwH^utwinpnt-, the scum and batch lines were moved back approximately 8 to 10 feet in the furnace,
Recently a plant producing high quality glass converted to use of the burner syibiatw and method according to the present invent:iotj. the user was able to achieve much higher furn^cm charging rates and higher furnace packing rates than With prior krt oxy-fuel burners heating the furnace. THi* use has confirmed that higher flame r^ttiai-ioil results in more efficient heat transfer to th« gl*»»l malt and may lead to fuel and oxygen savings ov«r dqtJVWltional oxy-fuel -melting systems. The industrial Wmt has confirmed higher radiation has proven to effectively reduce scum which has a direct bearing on improvih? the quality of glass produced-

Having thus described our invention what is desired to be secured by Letters Patent of the United States is set forth in the appended claims.



1. A staged oxy-fu*X tmrriet' for producing a generally flat luminous flam© comprising in combination:
a housing having a first and and a flame end, said housing having a cross-sootianul afrape with a width and height of different ciimfaftjtloft;
a fuel conduit having 4 I'itiit end and a nozzle end disposed in spaced relation to and generally concentrically within said hoUNinfJ dflid fuel conduit having a cross-sectional shapit coiftpXfitoentary to that of said housing thus defining a passage between said fuel conduit and said housing, said fuel nozzle having a width to height ratio of betwfeen 2 and 60, said nozzle end of said fuel conduit and said flame end of said housing adapted for positioning relative to each other along a longitudinal axis of said housing;
means to introduce fuel into said fuel conduit and an oxidizer into $4id passage between said fuel conduit and said housing, ©aid £u&l and oxygen exiting said nozzle end of said £u«l conduit to produce a flame; and
staging means to divert a portion of the total volume of oxidizer for •fificient combustion from said passage between said fu©l conduit and said housing, said staging means including a nozzle to introduce said diverted portion of said oxidizer beneath and coextensive with «4i
introduced beneath said flanta a fuel rich flame? overlying a highly radiative fuel lean flame is produced.
2. An oxy-fuel burner according to claim 1 wherein said width to height ratio of said fuel nozzle and said staging nozzle are between B and 30.
3. An oxy-fuel hurrter According to claim 1 adapted to operate at a firing rata oi! between 0.5 and 40 million Btu/hr.
4. An oxy-fuel burner according to claim 1 adapted to operate at a firing rata of between 1 and 20 million Btu/hr.
5. An oxy-fuel burner according to claim 1 wherein the width of the £u«I hoz^le and the staging nozzle are between 4 and 40 itteh3@.
6. An oxy-fuel burner according to claim 1 wherein the width of the fuel notbale «nd the staging nozzle are between 8 and 24 inohew.
7. An oxy-fuel bu*t*fi£ nocurding to claim 1 wherein said housing, said fUAl oundU.lt and said staging means includes an oxidizer conduit all having generally rectangular cross-s#atiuiltt ♦
8. A burner according to claim 1 wherein said housing, said fuel conduit Mid A*id staging means includes an oxidizer conduit All-hAVtUg generally arctuate elongated cross-sections.

9. A staged oxy-fual oombuator system comprising in combination:
s
an oxy-fuel burner having a housing having a first end and a flame end, said housing having a cross-sectional shape with a width and height of different dimensions, a fuel conduit having 4- first end and a nozzle end disposed in spaaed delation to and concentrically within said housing gaid fuel conduit having a cross-sectional shape complementary to that of said housing thus defining a paaaaga between said fuel conduit and said housing, said tnml nozzle having a width to height ratio of betwatm 2 and 60;
a precombustor mounted on Ha id burner, said precombustor having a first centraL passage complementary to and of a width and height equal to or larger than the width and height of: said burner housing said precombustor having a fitut and in fluid tight relation to the flame end of Mid IjpUHing and a second end adapted to direct said flaaw produced by said burner for heating in industrial aftV'ironmentsj the longitudinal axis of said precotnbuatotr being an extension of the longitudinal aicist of aaid housing of said burner, a second separata paaaaqa disposed beneath and coextensive with said firab c«utiral passage said second passage having a nozzla mncl tanninating in said second end of said precombuatur passaiJ® and nozzle adapted to direct a fluid underneath and generally parallel to said flame, said precombustor having a length of from 1 to 24 inohaa* ^^d
means to introduca {liel iftto said fuel conduit of said burner and an oxidizer into said

passage defined by said housing and Nftid nozzle conduit, and staging means to introduce an oxidizer into said second separate pasaage In imid precombustor whereby a fuel rich oxy-fuel flume overlays a highly radiative fuel lean flame beyond thai flame end of said precombustor.
I
10. A burner system Mod a fell act to claim 9 wherein said precombustor is b&ttyean 4 and 18 inches in length.
11j A burner system ftCcofding to claim 9 wherein said fuel nozzle and iftid second passage nozzle have a width to height ratio of between 5 and 30-1
12. A burner system according to claim 9 wherein the ratio of the hydraulic diameter of the flame end of the precombustot to the hydraulic diameter of the fuel nozzle in between 1 and 6.
13. A burner system according to claim 12 wherein the ratio is between 2 and 4,
14. A burner system according to claim 9 wherein walls defining the width of the first central passage and the second separate passage of the precombustor are disposed at an angle of between -15° \ to +30° on either side of a central axis of said precombustor.
15. A burner system aticottUttg to claim 14 wherein said angle is between 0° to t!S° on either side of a central axis of said precombustor.

16. A burner system according to claim 9 wherein walls defining the height of th© first central passage and the second separata passage of the precombustor are disposed at an jangle of between -15° to +20° on either side of a central &xia of said precombustor.
17. A method of producing a low NOx oxy-fuel flame for heating a furnace to an e'.tesr«t*d temperature comprising the steps of: producing a fuel rich oxy-fuel flame by using a post mix concentric) peonage oxy-fuel burner to produce said flame by equaling fuel to exit a central passage and oxygen to exit ® ticitoplementary passage surrounding said central passage said passages each having a width to height ratio of between 2 and 6 0 said fuel and oxygen exiting said burner at a minimum velocity of 15 ft/sec, introducing a highly radiative fuel lean flame underneath and aoextemive to said fuel rich flame; and introducing the generally flat, fuel rich flame overlying the fuel lewh flam® into said furnace. I
18. A method according to alalm 17 wherein said velocity for said fuel lean *n4 tuml rich flames exiting said burner are greater than 30 ft/sec*
19. A method according to blftim 17 wherein said fuel rich flame is directed into a precombustpr disposed on said burner said precombustor having a central passage with a shape complementary to and of a size equal to or greater than that of s&id passage surrounding said fuel passage, wherein said flame extends throughout the length of said precombustor without significant combustion occurring on the wall

forming the precombustor and iiaid fuel lean flame is' created and' directed by directing oxidizer underneath said fuel rich flame from a location at an exit end of said precombustor.
20. A method according to claim 19 wherein said precombustor directs said flame for a distance not to exceed 24 inches,
21♦ A staged oxy-fuel burnt* for producing a generally flat luminous flame ©^filing in combination substantially as herein dascrilM With reference to the accompanying drawings.


Documents:

1101-mas-1996-abstract.pdf

1101-mas-1996-assignment.pdf

1101-mas-1996-claims duplicate.pdf

1101-mas-1996-claims original.pdf

1101-mas-1996-correspondance others.pdf

1101-mas-1996-correspondance po.pdf

1101-mas-1996-description complete duplicate.pdf

1101-mas-1996-description complete original.pdf

1101-mas-1996-form 1.pdf

1101-mas-1996-form 26.pdf

1101-mas-1996-form 3.pdf

1101-mas-1996-other documents.pdf


Patent Number 207253
Indian Patent Application Number 1101/MAS/1996
PG Journal Number 26/2007
Publication Date 29-Jun-2007
Grant Date 01-Jun-2007
Date of Filing 21-Jun-1996
Name of Patentee M/S. AIR PRODUCTS & CHEMICALS INC
Applicant Address 7201 HAMILTON BOULEVSRD, ALLENTOWN,PA 18195-1501.
Inventors:
# Inventor's Name Inventor's Address
1 ALEKSANDAR GEORGI SLAVEJKOV 216 MURRAY DRIVE ALLENTOWN PA 18018-5320
PCT International Classification Number G01N21/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 08/523988 1995-09-05 U.S.A.