CA2162934A1 - Solar ignited landfill gas vent flare and flarehead - Google Patents

Abstract

A landfill gas vent flare is provided which includes a flarehead disposed in communication with a landfill gas vent wherein landfill gas is permitted to flow therethrough. A spark plug is located on the flarehead and is electrically connected to a solar powered ignitor which provides electrical impulses to the spark plug at regular predetermined intervals to generate a spark every 1.5 seconds to ignite the landfill gas and ensure the landfill gas burns continuously. The sparks are continuously generated regardless of the presence of landfill gas or flame in the flarehead. The flarehead comprises an inverted, modified frusto-conical structure and includes a plurality of inlets which permit air to enter the flarehead and mix with the landfill gas to facilitate combustion and to further ensure continuous burning of the gas.

Description

21 ~2934 80~AR ~ ~NDFI~ G~ ~EN~ ~LAR~ AND F~REHEAn ~ackground of the I~vention 1. Field of the In~ention This invention relates to means for controlling odors and greenhouse gas emissions from landfill6.
More particula~ly, the invention relates to gas ~lares disposed at capped landfills and adapted to burn landfill gas generated by the decomposition of organic waste.

2. ~ackg~ound Infor~tion As organic waste pr~sent ln a landfill decomposes, gas commonly known as "land~ill gas" is generated. This is a foul smelling gas that gencrally consists o~ 5S~ methane, 44% carbon dioxide lS and 1% of ot~er various constituents ranging from ~ydrogen sulfide to complex hydrocarbons. When released directly into the atmosphere, landfill gas may cause se~ere odor problems. Additionally, methane has been characterized as a "greenhouse" gas which is believed to significantly contribute to glo~al warming.
currently, once landfill~ have reached full capacity, they are generally capped with among other things, a layer of topsoil to support vegetation and help prevent erosion. A gas vent, gas well, or other gas collection system i~ also typically provided to enable the landfill gas generated by the aforementioned decomposition process to conveniently pass through the cap for release.
lo Because landfill gas burns relati~ely cleanly, the gas emerging from such a vent, etc. may be burned in an effort to eliminate the aforementioned noxious odor and harmful greenhouse effects. A flare may thus be provided to burn the gas as it emerges from the vent. However, significant disadvantages inhere in this approach which tend to of~set the advantages thereof. Pa~ticularly, once such a ~lare ha~ been ignited, it may be difficult to ensure that the flame burns continuously. Several factors contribute to this difficulty, including variations in the flow rate of the gas as a result of environmental conditions such as temperature and ground water level6. Variations in the percentages of the constituents of the landfill gas, namely, ~ethane and c02, may alfio afrect th~ optimum gas/air ratio mixture required to maintain a continuous flame.
Moreover, adverse weather conditions such as wind and precipitation may tend to extinguish the flame.
Because such flares are preferably disposed proximate to the landfill to minimize the use of lengthy gas pipe runs, the rlares are usually disposed in remote locations, where it would be difficult to monitor the presence o~ flame and inconvenient to manually re-igni~e the flares in the event the flame is extinguished. Moreover, during any time in which the flame is out, the gas is permitted to escape into the atmosphere, thereby creating potentially lengthy periods in which the odor and greenhouse e~fects of the landfill are not being treated.
In attempt~ to remedy this drawba~, several devices may be utilized. In particular, vent rlares may be pro~ided with electronic ignitors or propane pilot lights. Electronic ignitors generally include sophisticated technology to monitor the presence of ~lame~ In particular, optical or heat sensors may be employed, w~ich, upon detecting an absence of flame, signal electronic circuitry to automatically re-ignite the gas. A drawback o f this approach is that such sophisticated equipment is relatively expensi~e, involving substantial up-front capital expenditure, while also requiring a relatively high degree o~
routine ~aintenance.
Propane pilot light systems, on the ot~er hand, ~elp ensurQ that the landfill gas flame burns continuously by providing a continuously burning pilot light. This type of system has the advantage of being relatively unsophisticated and thus relatively inexpensive to purchase and simple to maintain. A drawbacX o~ this approach however, is that the system requires a separate supply o~ fuel (propane) which must ~e replaced periodically. In addition, the pilot light itself may ~e extinguished, by, for example, wind and/or precipitation and thus still require manual re-ligh~ing.
A need therefore exists for an improved landfill gas vent flare that is relati~ely inexpensive, requires little maintenance, yet sQrves to reliably maintain a continuou~ flame under a wide range of operating conditions.

Rummary of the Invont~on According to an em~odiment of this invention, a landfill gas vent flare includes a flarehead adapted ~or communication with a landfill gas vent wherein landfill gas is permitted to flow in a downstream direction from the la~dfill gas vent to the ~larehead. ~ ~park initiator is disposed on the ~larehead and generates a continuous series of sparks in the flarehead wherein the land~ill gas ~lowing therethrough is ignited and continuously burned.
Advantageou61y, the continuous series of ~parks generated ~y the subject invention, in a relatively simple and inexpensive manner, serves to ignite the gas flowing through the ~larehead and reliably ensUre that the gas burns continuously under a wide range of environmental and other operating conditions.
The above and other objects and advantagea of this invention will be more readily apparent from a reading of the ~ollowing description of an exemplary embodiment ther~o~ taken in conjunction with the following drawing.

Brief Description o~ the Drawing~

F~G. 1 is schematic elevational front view of the landfill gas vent flare of the subject invention disposed in operative engagement with a landfill gas vent;
F~G. 2 i5 a plan view of the flarehead of the landfill gas vent flare of ~IG. 1;
FIG. 3 is an elevational view of the flarehead of ~IG. 2;
FIG. 4 is a cross-~ectional view of the flarehead taXen along 4-4 o~ FIG. 2; and ~ IG. 5 is a view similar to that of FIG. 3, of an alternate embodiment o~ the flarehead.

Detailed Description of the Preferred Rm~oA;~ent Brie~ly dQscribed, as shown in ~IG. 1, the s~bject invention comprises a solar powered la~dfill gas vent flare 10 which serves to control landfill odors and abate greenhouse gas emissions from landfills by burning landfill gas as it emerges from a gas vent 12 The gas vent may ~e connected to a gas well (not shown) or other gas collection system located at a landfill site. The landfill gas ~ent flare comprises a conduit or gas flow me~ber 14 fastened to vent 12, which serves to permit landfill ga~ to flow therethrough from the vent to a flarehead 15 where the ga~ is ignited and ~urned. Igni~ion i~
provided by a solar powered ignitor 16 WhiCh ~upplies a continuous series of high ~oltage impulses to a spark initiator or spark plug 18 so that a spark is generated in the flare~ead every l.S seconds. Th~s continuous sparking helps ensure that the gas in the flarehead is reliably ignited and continuously burned, under a ~ariety of conditions, without the need for expensive flame monitoring eguipmQnt or secondary fuel sources. In addition, the flarehead O i5 provided with a geometry and series of inlet~, as at 74 & 76, which facilitate mixing o~ the landfill ga~ with air to promote co~bustion and help ensure 2 ~ 62934 that the flame will be self sustaining even in ad~erse weather conditions.
For the purposes of this specification, the term "vent" shall be de~ined herein as any conduit, pipe or ~imllar member disposQd to convey l~nd~ill ga~
from a land~ill, including, but not limited to, a pipe comprising a component of a conventional vent, well, or other ga~ collection system located at a landfill site.
lo Referring now to FIG. 1 in detail, conduit 14 prefera~ly comprises a metallic pipe and is fastened in an air tight fashion to an exposed end of vent 12 to communicate with and permit the landfill gas to ~low therethrough in a downstream direction indicated by arrow a. In a preferred embodiment, such fastening is accomplished in a conventional manner ~uch as by threadably disposing a bushing 22 on one end of ~he pipe, thread~b~y or otherwise fastening the bushing to ~ pipe flange 24 and mating the pipe flange to a similar ~lange 26 disposed on the exposed end of vent 12. Flanges 24 and 26 may con~eniently be maintained in mating engagement using threaded fasteners 27 as shown. Both conduit 14 and bushing 24 a~e prefe~ably fabricated from ~lack iron.
A valve 28, pre~erably a conventional ~tainless steel ball valve, is provided at a predetermined point along the length of conduit 14, to permit a user to ~ontrol the rate of flow ôf the gas therethrough to vary the size of flame or to shut off 30 the gas flow entirely. A flame arrestor 32 is disposed at a predetermined position along the length of conduit 14, downstream of ~all valve 28 and pre~erably proximate a terminal e~d 3 0 of the conduit, as will be di~cus~ed her~inafter. The flame arrestor i~ of a conventional construction, a suitable example being Model ~FA-100, manufactured by Land~ill Tochnologies, Inc. of West Sand Lake, New ~ork. Briefly described, this deYice comprises a cylindrical housing with a pair of cylindrical arrestor pads 34 disposed therein. The pads preferably comprise a por~us stainless steel wire gauze, similar in con~truction to a con~entional lo ~couring pad and are easily replaceable for routine maintenance, as will be discussed hereina~ter. The fla~e arrestor (as well as pads 34) is disposed concentrically with conduit 14, in blocking relation thereto 50 that the landfill gas passes through the 15 pads when flowing in the downstream direction. The flame arrestor operates in a conventional manner to prevent ignited gases from ~backflashing" upstream of the flame arrestor ~or safety purposes.
As mentioned hereinabove, the landfill gas is burned once it reaches flarehead 15 disposed at terminal end 30 of the conduit, proximate and downstream of flame arrestor 32. As will be discussed in greater detail he~eina~ter w~th regard to FIGS. 2-5, the ~larehead is pre~erably ~abricated from a metallic material, such as black iron and includes walls which diverge in the downstream or gas flow direction to provide a modified frusto-conical or bell shaped structure. Air inlets, such as slot 74 and orif ices 76, are disposed about the flarehead and will also be di~cussed in greater detail hereinafter.
~ s also mentioned briefly hereinabo~e, ignition o~ the gas in the flarehead is provided by a solar powered ignitor 16. A preferred ignitor is commercially available and known as a SFI-100 Solar Ignitor availa~le ~rom ~andfill TechnologiQs, Inc., of West Sand ~ake, New YorX. The ignitor may be disposed at any location proximate the flarehead, while as shown, may preferably be fastened to conduit 14 using conventional fastening means, such as, for example, pipe clamps tnot shown).
Brie~ly described, the ignitor includes a solar lo collector 36 which charges a ~attery (not shown), a transformer (not shown) to step up the voltage of the ~attery output and a time keeping device which sends high voltage impulses to hot line terminal 38 at predetermined intervals. Terminal 38 is electrically connected to spark initiator such as a spark plug 18 disposed on the flarehead by a hot line ignition ca~le 40 of a predetermined length, in combination.
with a spark strap 42. The spark strap, which is preferably fabricated from stainless steel, may be uninsulated and fastened to cable 40 using a conventional connector bolt 44. Both cable 40 and strap 42 are preferably fastened to conduit 14 using a conventional combination of insulators 48 and metallic pipe clamps 50.
The ignitor further includes an On/Off switch 46, ground terminal 48 and a ground cable 50 connected to the terminal, conduit 14 and a ~teel ground sta~e (not s~own) to ef~ectively ground nominally the entire landfill gas vent flare 10, including flarehead 15. One skilled in the art will recognize that such grounding, while providing important safety benefits, is necessary to enable proper operation of spark plug 18.

Thus connectQd, the ignitor supplies a continuous series of high voltage impulses to the sparX plug which in turn, generates a series of sparks in the flarehead at predetermined intQrvals ~o ignite the gas flowing thereto. Such continuous spark generation s~rvQs to effectively ignite the gas and subsequently re-ignite it in the event the flame is extinguished due to ad~erse weather conditions, variations in gas flow rate, or varying percentages lo of constituent gases in the landfill gas. Moreover, the interval between sparXs is preferably close enough to maintain a substantially continuous flame in the flarehead by effectively re-igniting the flame before it has a chance to be extinguished as a result of one or more of the a~ove described conditions or variations. Thu~, the interval may co~veniently be between approximately l and 2 seconds, or preferably 1.5 seconds.
Accordingly, an important advantage of this continuous spark generation is that the aforementioned re-ignition of the gas in the event the flame has been, or is about to be extinguished ~or some reason, is accomplished without the need for sophisticated and expensive flame status monitoring, such as typically provided with p~ior art electrical ignition systems, or conventional pilot light systems which require a separate supply of fuel such as propane to ~uel the pilot light. Moreover, this advantage is provided without the need for ~ine 30 tuning the flare to compensate for the aforementioned variations in gas ~low rate or percentages in constit~ent gases, since even in the event of conditions which would under normal conditions be in~ufficient to provide a self-sustaining ~lame, the continuous sparking of the present invention wo~ld re-ignite the gas with sufficient ~requency as to effectively create a continuous flame.
A further advantage of this invention, is that the battery of the ignitor can supply enough energy ~o operate the spar~ plug continuously for a~proximately two wee~s without recharge from the solar collector 36. Thus, the system is unaffected by relatively long periods of overcast ~eather.
Referring now to FIGS. 2-5, as mentioned hereinabove, flarehead 15 generally comprises a modif~ed ~rusto-conical or bell shaped structure, wherein the landfill gas flows in the downstream or gas flow direction a (FIG. 4) from apex end 52 to base 54 thereof. Referring specifically to FIG8. 3 &

4, in a preferred embodiment, the flarehead includes a cylindrical neck S6, having a predetermined inner diameter dl (FIG. S), which threadably, or other~ise, fastens to flame arrestor 32 (FIG. 1) as di~cussed hereinabove. The neck fairs, at apex 52, into a . first frusto-conical portion 58, which, in turn, fairs ~nto an intermediate cylindrical portion 60.
Portion 60 has a predetermined diameter d~ (FIG. 4) which is greater than ~1, Qxtends for a predetermined distance in direction a, then ~airs into second frusto-conical portion 62. Second frusto-conical portion 62, in turn, fairs into cylindrical end portion 64 which has a predetermined diameter ~
(F~G. 4) ~reater than d2. End portion 62 extends for a predetermined distance in direction a, and terminates at base 54.

Overall dimensions of flarehead 15 are not critical, and one skilled in the art will recognize that ~pecific dimensions of t~e general structure desc~ibed herQin may be determined with regard to the S intended application, including expected volume and flow rate of the landfill gas and size of *lame desired. However, in a preferred embodiment, the ratio o~ the diameters to one another, namely, dl:d2:d3 is approximately 1.5:4:10. The ratio o~
overall length of flarehead 15 ~rom apex 52 to base 54, as indicated by 11 in ~IG. 4 to d3 (ll:d3) iB
preferably within the range o~ .8:1 to 1.5:1.
As mentioned hereinabove, ai~ inlets are disposed about the f~arehead to permit air to mix lS with the landfill gas and thus facilitate combustion thereof.
Referring now to ~IG~. 2-4, t~e air inlets include a plurality of apertures 72 circumferentially spaced about first frusto-conical portion 58, proximate apex end 52. Additional inlets, comprising a plurality of elongated slots 74, are also spaced circum~erentially about first ~rusto-conical portion 58, at a predetermined distance downstream Or said apertures. As shown, each o~ the elongated 510ts is oriented so tha~ tho longitudinal dimension thereof is di~posed in the circumferential direction o~ the flarehead, or transverse to flow direction a.
Air inlets further include a set of circumferentially spa~ed first orifices 75, (first set) and a ~et of similarly spaced second orifices.
76, (second set), both sets being s~bstantially dispo6ed on second frusto-conical portion 62. ~irst and second orifices 75 & 76, respectively, have 2 ~ 62934 ~referably substantially s~milar, predetermined dia~eters which are greater than that of apertures 72. The second set of ori~ices 76 i~ disposed downstream of the first set of orifices 75.
Moreover, the first ~Qt is of~set relative to the second 6et wherein each ori~ice 75 & 76 is disposQd at a different radial position along the perip~ery of the flarehead Further, in a pre~erred ~ bo~;men~ as shown, the afore~entioned offset is such that each lo first orifice ~S i~ disposed equidistantly from the two nearest s~cond orifices 76, and ~ice-versa, to evenly stagger the ori~ices such that orifices 75 and 76 are alternately disposed at ~ constant radial intervals, as in~icated by a in ~G. 2, about the circumference of the flarehead.
As shown in ~IG5. ~-5, a plurality of elongated slits 78 are spaced at constant radial interval~
about the circum~erence of cylindrical end portion 64 and extend in an upstream direction a predetermined distance from base 54. As also shown, spark initiator 18 preferably comprises a conventional spark plug which is threadably engaged to the flarehead to provide ignition sparks the~ein. AS
mentioned hereinabove, thQ rlareheAd is ~abricated from electrically conductive material, pre~erably ~lack iron, and is grounded to permit proper operation of ~he spark plug.
As shown in ~IG5. 2-4, the spark plug is disposed along cylindrical end portion 6~ of the flarehead to ignite gas flows of relati~ely high vo~ume and/or ~elo~ity. Al~ernati~ely, the spark plug may be disposed at a position further up6~ream, such as indicated in FIG. 5, to igni~c gas ~lows o~

2 t 62934 relatively low volume and/or velocity. As shown, the alternate position of the spark plug is preferably along intermediate cylindrical portion 60.
The con~truction of the subject invention thus provide~ se~eral important benefits. Particularly, the air inlets, in combination with the overall geometry of the ~larehead as shown and described herein, in and of themselves, help ensure adequate mixing of the landfill gas with ambient air, to lo ensure t~at the land~ill gas ~urns in a continuous, self-sustaining manner, even in varying weather conditions. Moreover, aS discussed he~einabove, the aforementioned Gontinuous ignition also serves to provide a continuous, sel~-sustaining flame under a wide variety of conditions. Thus, thQ combination of these features, along with the aforementioned ability to place the spark plug optimally for given gas floW
parameters, serve to provide an inexpensive and reliable gas ~ent flare. .
A preferred embodime~t of the invention having been fully described, the following is a description of the operation thereof.
once the subject in~ention has been installed as set ~orth hereinabove, a user need simply mount ~park plug 1~ in one of the a~orQmentioned spark plug locations, depending on the intended volume and/or velocity o~ gas flow. Valve lB is ~hen opened to permit the land~ill gas to flow through conduit 14 and switch 46 is actuated to ignite the gas in flarehead 15. once ignited, the user may modulate the valve 28 to optimize the size of the ~lame relative to the spark plug position. Once the ~alve is so adjusted, no ~urther action is necessary by the ~ser, other than routine maintenance such as cleaning and/or replacing flame arrestor pads 34 and spark plug 18.
The foregoing description is intended primarily for purposes of illustration. Although the invention has been 6hown and described with respect to an exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, o~issions, and additions in the form and detail ther~of may b~ made therein without departing from the spirit and scope of the invention.

PARTS LIST
land~ll gas vent flare 12 landfill gas vent 14 conduit or gas flow member flarehead 16 ignitor 18 ~park initiator or spark plug 22 bushing 24 pipe flange 26 flange 27 threaded ~asteners 28 ball valve terminal end (conduit) 32 rlame arrestor 34 arrestor pads 36 solar collector 38 hot line terminal ~0 ignition cable ~2 spark strap 44 connector ~olt 46 On/Off switch 48 insulators pipe clamps 52 apex end 54 base 56 neck 58 first frusto-conical portion intermediate cylindrical portion 2 1 62~34 62 second frusto-conical portion 64 cylindrical end portion 72 apertures 74 elongate~ slots fir~t ori~ices 76 second orifices 78 elongated slits Having thus described the in~ention, what is claimed is:

Claims (41)

1. A landfill gas vent flare comprising:
a flarehead adapted for communication with a landfill gas vent wherein landfill gas is permitted to flow in a downstream direction from the landfill gas vent to said flarehead;
at least one spark initiator disposed on said flarehead and adapted to generate a continuous series of sparks in said flarehead wherein the landfill gas flowing thereto is ignited and continuously burned.

2. A landfill gas vent flare according to claim 1, further comprising an ignitor disposed in electrical contact with said spark initiator to supply electrical energy thereto at regular predetermined intervals to generate said continuous series of sparks.

3. A landfill gas vent flare according to claim 2, wherein said ignitor is solar powered.

4. A landfill gas vent flare according to claim 2, further comprising a gas flow member which communicates at a first end thereof with the landfill gas vent and at a second end thereof with said flarehead to receive and convey the landfill gas from the vent to said flarehead.

5. A landfill gas vent flare according to claim 1, wherein said continuous series of sparks is generated regardless of the presence of landfill gas or flame in said flarehead.

6. A landfill gas vent flare according to claim 5, wherein a spark is generated every 1.5 seconds.

7. A landfill gas vent flare according to claim 1, further comprising a flame arrestor disposed upstream of said flarehead to prevent backflash of ignited gases.

8. A landfill gas vent flare according to claim 7, wherein said flame arrestor is disposed between the vent and said flarehead.

9. A landfill gas vent flare according to claim 7, further comprising a flow control valve disposed upstream of said flarehead to regulate rate of flow of the landfill gas thereto from the landfill gas vent.

10. A landfill gas vent flare according to claim 1, wherein said flarehead is adapted to mix air with the landfill gas to facilitate combustion thereof.

11. A landfill gas vent flare according to claim 10, wherein said flarehead comprises at least one inlet to permit air to enter said flarehead and mix with the landfill gas.

12. A landfill gas vent flare according to claim 11, wherein said flarehead is generally frusto-conical and the landfill gas flows downstream therethrough from an apex end to a base thereof.

13. A landfill gas vent flare according to claim 12, wherein said at least one inlet further comprises a plurality of apertures disposed in spaced relation about a circumference thereof proximate said apex end.

14. A landfill gas vent flare according to claim 13, wherein said at least one inlet further comprises a plurality of elongated slots disposed in circumferentially spaced relation about said flarehead at a position downstream of said apertures, each of said elongated slots having a longitudinal dimension which extends in a circumferential direction relative to said flarehead.

15. A landfill gas vent flare according to claim 14, wherein said at least one inlet further comprises a first set and a second set of circumferentially spaced orifices, said first set being disposed downstream of said elongated slots, said second set being disposed downstream of said first set, and said first set being offset relative to said second set wherein each orifice of said first set and said second set is disposed at a discrete radial position along the periphery of said flarehead.

16. A landfill gas vent flare according to claim 15, wherein said at least one inlet further comprises a plurality of elongated slots disposed in spaced relation about the periphery of said base, each of said slots extending a predetermined distance upstream from said base.

17. A method of treating gaseous landfill emissions comprising the steps of:
disposing a flarehead proximate a landfill gas vent to permit flow of landfill gas thereto;
and generating a continuous series of sparks in said flarehead wherein the landfill gas flowing therethrough is ignited and continuously burned.

18. A method of treating gaseous landfill emissions according to claim 17, wherein said step of generating a continuous series of sparks further comprises:
disposing an ignitor in electrical contact with a spark initiator; and supplying electrical energy from the ignitor to the spark initiator at regular predetermined intervals.

19. A method of treating gaseous landfill emissions according to claim 18, wherein said step of generating a continuous series of sparks further comprises:
generating the sparks regardless of the presence of landfill gas or flame in said flarehead.

20. A method of treating gaseous landfill emissions according to claim 19, wherein said step of generating a continuous series of sparks further comprises:
generating a spark approximately every 1 to 2 seconds.

21. A method of treating gaseous landfill emissions according to claim 20, wherein said step of generating a continuous series of sparks further comprises:
generating a spark substantially every 1.5 seconds.

22. A method of treating gaseous landfill emissions according to claim 18, wherein said ignitor is solar powered.

23. A method of treating gaseous landfill emissions according to claim 18, further comprising the step of:
disposing a flame arrestor proximate the flarehead to prevent backflash of ignited gases into the landfill gas vent.

24. A method of treating gaseous landfill emissions according to claim 23, further comprising the step of:
regulating rate of flow of the landfill gas to the flarehead.

25. A method of treating gaseous landfill emissions according to claim 17, further comprising the step of:
mixing air with the landfill gas to facilitate combustion thereof.

26. A method of treating gaseous landfill emissions according to claim 25, further comprising the step of:
disposing at least one inlet in the flarehead to permit the air to enter the flarehead and mix with the landfill gas.

27. A method of treating gaseous landfill emissions according to claim 26, wherein said step of disposing at least one inlet in the flarehead further comprises disposing a plurality of inlets at predetermined locations about the flarehead.

28. A flarehead for a landfill gas vent flare adapted to permit landfill gas to flow therethrough in a downstream direction from an apex end to a base thereof, comprising:
a first frusto-conical portion depending from said apex end, which fairs, in the downstream direction, into an intermediate cylindrical portion; said intermediate cylindrical portion extending a predetermined distance in said downstream direction and fairing into a second frusto-conical portion;
said second frusto-conical portion in turn fairing into a cylindrical end portion which terminates at said base.

29. A flarehead for a landfill gas vent flare according to claim 28, wherein said apex end is an annular orifice having a predetermined first diameter, said intermediate cylindrical portion having a predetermined second diameter which is greater than said first diameter, and said cylindrical end portion having a predetermined third diameter which is greater than said second diameter.

30. A flarehead for a landfill gas vent flare according to claim 29, wherein a ratio of said first diameter to said second diameter to said third diameter is approximately 1.5:4:10.

31. A flarehead for a landfill gas vent flare according to claim 30, wherein an overall length of said flarehead is defined as distance in the downstream direction from said apex end to said base, and a ratio of said overall length to said third diameter is preferably within the range of .8:1 to 1.5:1.

32. A flarehead for a landfill gas vent flare according to claim 29, further comprising a plurality of inlets disposed thereabout to permit ambient air to enter said flarehead and mix with the landfill gas.

33. A flarehead for a landfill gas vent flare according to claim 32, wherein said inlets further comprise a plurality of apertures disposed in circumferentially spaced relation about said first frusto-conical portion.

34. A flarehead for a landfill gas vent flare according to claim 33, wherein said inlets further comprise a plurality of elongated slots disposed in circumferentially spaced relation about said first frusto-conical portion at a predetermined distance downstream of said apertures, each of said elongated slots having a longitudinal dimension which extends in a circumferential direction relative to said flarehead.

35. A flarehead for a landfill gas vent flare according to claim 34, wherein said inlets further comprise a first set and a second set of circumferentially spaced orifices, both said first set and said second set being substantially disposed on said second frusto-conical portion, said second set being disposed downstream of said first set, and said first set being offset relative to said second set wherein each orifice of said first set and said second set is disposed at a discrete radial position along the periphery of said flarehead.

36. A flarehead for a landfill gas vent flare according to claim 35, wherein said inlets further comprise a plurality of elongated slits disposed in spaced relation about the periphery of said cylindrical end portion, each of said slits extending a predetermined distance in the upstream direction from said base.

37. A flarehead for a landfill gas vent flare adapted to permit landfill gas to flow in a downstream direction therethrough, comprising:
a first frusto-conical portion wherein landfill gas flows downstream therethrough from an apex end to a terminal end thereof;
a plurality of apertures disposed in circumferentially spaced relation about said first frusto-conical portion;

a plurality of elongated slots disposed in circumferentially spaced relation about said first frusto-conical portion at a predetermined distance downstream of said apertures, each of said elongated slots having a longitudinal dimension which extends in a circumferential direction relative to said flarehead; wherein said apertures and elongated slots are adapted to permit ambient air to enter said flarehead and mix with the landfill gas to facilitate combustion thereof.

38. The flarehead of claim 37, wherein said first frusto-conical portion fairs, in the downstream direction, into an intermediate cylindrical portion;
and said intermediate cylindrical portion extends a predetermined distance in said downstream direction.

39. The flarehead of claim 38, wherein said intermediate cylindrical portion fairs, in the downstream direction, into a second frusto-conical portion;
said second frusto-conical portion having a first set and a second set of circumferentially spaced orifices disposed substantially thereon, being adapted to permit ambient air to enter said flarehead and mix with the landfill gas to facilitate combustion thereof;
said second set being disposed downstream of said first set; and said first set being offset relative to said second set wherein each orifice of said first set and said second set is disposed at a discrete radial position along the periphery of said flarehead;

40. The flarehead of claim 39, wherein said second frusto-conical portion fairs into a cylindrical end portion which terminates at a base of said flarehead;
a plurality of elongated slits are disposed in spaced relation about the periphery of said cylindrical end portion; and each of said slits extend a predetermined distance in the upstream direction from said base.

41. The flarehead of claim 40, wherein said apex end is an annular orifice having a predetermined first diameter;
said intermediate cylindrical portion has a predetermined second diameter which is greater than said first diameter; and said cylindrical end portion has a predetermined third diameter which is greater than said second diameter.