Information
-
Patent Grant
-
6464491
-
Patent Number
6,464,491
-
Date Filed
Wednesday, November 29, 200024 years ago
-
Date Issued
Tuesday, October 15, 200222 years ago
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Inventors
-
-
Examiners
Agents
- Christensen O'Connor Johnson Kindness PLLC
-
CPC
-
US Classifications
Field of Search
US
- 431 5
- 431 170
- 431 202
- 110 210
- 110 214
- 110 250
- 422 169
- 422 174
- 422 189
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International Classifications
-
Abstract
A gas flare includes an elongate primary combustion chamber and at least one supplementary combustion chamber. A primary burner is positioned in the primary combustion chamber. A secondary burner is positioned in the supplementary combustion chamber. The primary combustion chamber has an outlet which is coupled with an inlet to the supplementary combustion chamber. A flow path is created for waste gas past the primary burner in the primary combustion chamber and past the supplementary burner in the supplementary combustion chamber, so the waste gas is subjected to multiple burner exposure for more complete combustion.
Description
FIELD OF THE INVENTION
The present invention relates to a gas flare.
BACKGROUND OF THE INVENTION
Many oil wells produce small quantities of waste gas. The normal procedure has been to dispose of such small quantities of waste gas with a gas flare. In recent years, government regulations relating to protection of the environment have become more stringent. Flaring of waste gas is prohibited unless it meets emission standards. The oil wells that have been most affected by the more stringent regulations are those that produce hydrogen sulfide gas, commonly known as “sour” gas. Oil wells producing small quantities of sour gas are being shut down, as existing gas flare technologies are either incapable of meeting emission standards or so costly that the oil wells are no longer economically viable when equipped with such gas flares.
SUMMARY OF THE INVENTION
What is required is a gas flare that is capable of meeting stringent emission standards at a comparatively low cost.
According to the present invention there is provided a gas flare, which includes an elongate primary combustion chamber having a first end, a second end, an inlet at the first end, and an outlet at the second end. A primary burner is disposed between the first end and the second end. At least one elongate supplementary combustion chamber is also provided having a first end, a second end, an inlet at the first end, and an outlet at the second end. A supplementary burner is disposed between the first end and the second end. The outlet of the primary combustion chamber is coupled with the inlet of the supplementary combustion chamber, such that a flow path is created for waste gas past the primary burner in the primary combustion chamber and past at least one supplementary burner in the supplementary combustion chamber, whereby the waste gas is subjected to multiple burner exposure.
A gas flare constructed in accordance with the present invention operates on the principle that more complete combustion of waste gases is obtained when the waste gases are subjected to multiple burners. The preferred configuration involves supplementary combustion chambers which are stacked on top of the primary combustion chamber.
Once the basic teachings of the present invention are understood there are further measures that can be taken to increase efficiency. In order to ensure there is adequate oxygen for combustion, each of the supplementary combustion chambers has a supplementary source of combustion air. In order to ensure that the heat is sufficient to ensure as complete a burn as possible, the primary burner and each of the supplementary burners is an electric heating element. Electric heating elements permit greater temperature control.
Although beneficial results may be obtained through the use of the gas flare, as described above, even more beneficial results may be obtained when the outlet of the last of the supplementary combustion chambers is connected to a cooling and chemical reaction chamber. This enables chemicals to be introduced into and react with the waste gas as it cools. The addition of chemicals can turn the residue of the waste gas into a usable byproduct. For example, the addition of ammonia in controlled quantities can turn sour gas residue into fertilizer.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:
FIG. 1
is a schematic diagram of a gas flare fitted onto a source of waste gas.
FIG. 2
is a side elevation view in section of the gas flare shown in FIG.
1
.
FIG. 3
is an end elevation view in section of the gas flare shown in FIG.
1
.
FIG. 4
is a schematic diagram of the gas flare shown in
FIG. 1
with heat exchange capability.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a gas flare generally identified by reference numeral
10
, will now be described with reference to
FIGS. 1 through 4
.
Referring to
FIG. 1
, gas flare
10
includes a body
12
and an insulating enclosure
14
. A gas feed line
16
feeds gas into an air feed line
18
. Air is driven along air feed line
18
by a first fan
20
and through a first flame arrestor
22
and a venturi
24
. The action of the air passing through venturi
24
draws a combustible waste gas along gas feed line
16
from a source
26
, such as a tank, through a check valve
28
and a second flame arrestor
30
. The mixture of waste gas and air is forced from venturi
24
through insulating enclosure
14
via an inlet
32
into a first elongate primary combustion chamber
34
of body
12
.
Referring to
FIG. 2
, insulating enclosure
14
has a body
36
and a lid
38
. Body
36
of insulating enclosure
14
has a base
42
and peripheral sidewalls
44
extending upward from base
42
to an upper peripheral edge
46
, defining an interior cavity
48
. A gasket
50
provides an air tight seal between upper peripheral edge
46
of peripheral sidewalls
44
and a periphery
56
of bottom surface
58
of lid
38
.
Body
12
of gas flare
10
is constructed of a material capable of withstanding exposure to temperatures up to 3000 F. without sustaining damage or distortion. Body
12
of gas flare
10
has several levels, including elongate primary combustion chamber
34
positioned at a first level, an elongate first supplementary combustion chamber
52
positioned at a second level, and an elongate second supplementary combustion chamber
54
positioned at a third level. There are several ways in which the levels of body
12
can be assembled. Referring to
FIG. 3
, it has been found that one method by which the levels of body
12
can be stacked so as to minimize heat losses and to minimize the a size of interior cavity
48
of insulating enclosure
14
within which body
12
is located is as follows. Each of primary combustion chamber
34
, first supplementary combustion chamber
52
and second combustion chamber
54
has peripheral sidewalls
106
and a base
108
. Sidewalls
106
of each of first supplementary combustion chamber
52
and second supplementary combustion chamber
54
extend below base
108
. A peripheral trough
110
extends around an interior surface
111
at an upper peripheral edge
112
of sidewalls
106
of each of primary combustion chamber
34
and first supplementary combustion chamber
52
. Each of first supplementary combustion chamber
52
and second supplementary chamber
54
are sized such that a lower peripheral edge
116
of sidewalls
106
can sit within trough
110
of the level immediately below. A gasket
118
provides for a gas tight seal between lower peripheral edge
116
of sidewalls
106
and trough
110
. Base
108
of first supplemental combustion chamber
52
encloses a top of primary combustion chamber
34
and base
108
of second supplementary combustion chamber
54
encloses a top of first supplementary combustion chamber
52
. A lid
120
closes the top of second supplementary combustion chamber
54
. A gasket
122
provides for a gas tight seal between an upper peripheral edge
124
of sidewalls
106
of second supplemental combustion chamber
54
and lid
120
.
Referring to
FIG. 2
, primary combustion chamber
34
has a first end
60
and a second end
62
. Inlet
32
feeds the mixture of air and combustible gas into primary combustion chamber
34
at first end
60
as indicated by arrow
78
. A primary burner
64
in the form of an electric heating element is disposed between first end
60
and second end
62
. An outlet
66
is at second end
62
of primary combustion chamber
34
.
First supplementary combustion chamber
52
has a first end
68
, a second end
70
, an inlet
72
at first end
68
, an outlet
74
at second end
70
, and a first supplementary burner
76
in the form of an electric heating element disposed between first end
68
and second end
70
. When the levels of body
12
are stacked as shown in
FIG. 2
, outlet
66
of primary combustion chamber
34
is coupled with inlet
72
of first supplementary combustion chamber
52
. Referring to
FIG. 1
, a second fan
82
forces air through a first supplementary air inlet
83
into first supplementary combustion chamber
52
, as indicated by arrow
85
to support combustion of the waste gas by first supplemental burner
76
.
Referring to
FIG. 2
, second supplementary combustion chamber
54
has a first end
84
, a second end
86
, an inlet
88
at first end
84
, an outlet
90
at second end
86
, and a second supplementary burner
92
in the form of an electric heating element disposed between first end
84
and second end
86
. Referring to
FIG. 1
, a third fan
96
forces air through a second supplementary air inlet
98
into second supplementary combustion chamber
54
, as indicated by arrow
100
to support combustion of the waste gas by second supplemental burner
92
. When the levels of body
12
are stacked as shown in
FIG. 2
, outlet
74
of first supplementary combustion chamber
52
is coupled with inlet
88
of second supplementary combustion chamber
54
. A flow path is created for waste gas past primary burner
64
in primary combustion chamber
34
as indicated by arrow
78
, past first supplementary burner
76
in first supplementary combustion chamber
52
as indicated by arrow
80
, and past second supplementary burner
92
in second supplementary combustion chamber
54
as indicated by arrow
94
. The waste gas thereby is subjected to multiple burner exposure before exiting second supplementary combustion chamber
54
via outlet
90
, as indicated by arrow
102
.
The use of electric heating elements for primary burner
64
, first supplementary burner
76
and second supplementary burner
92
with insulating enclosure
14
enables a temperature in each of the levels of body
12
to be kept substantially constant during operation of gas flare
10
.
The provision of air through first supplementary air inlet
83
and second supplementary air inlet
98
ensures that the ratio of air to waste gases is high enough so that sufficient air is available for the complete combustion of waste gases from source
26
. A ratio of 10 volumes of air for each volume of waste gases has been found to be sufficient for several applications using gas flare
10
.
Referring to
FIG. 1
, first flame arrestor
22
and second flame arrestor
30
serve to prevent flash back from gas flare
10
into air feed line
18
and gas feed line
16
in the event that there is a power failure and first fan
20
is not operating.
The nature of the products from combustion of waste gas either may be harmful, and so cannot be discharged into the atmosphere, or may be valuable as chemical feedstock, and so may be worth capturing. For example, when the waste gas contains hydrogen sulfide, combustion of said waste gas produces oxides of sulfur. It is undesirable to vent oxides of sulfur as they are harmful pollutants and they are a factor in the formation of acid rain. It is therefore desirable to scrub oxides of sulfur from the exit gases from second supplementary combustion chamber
54
. Oxides of sulfur can be reacted with other chemical reagents to form useful and valuable products, such as a reaction with ammonia to form a compound valuable as a fertilizer. Referring to
FIG. 1
, outlet
90
of second supplementary combustion chamber
54
is connected to a combination of a cooling chamber
130
and a chemical reaction chamber
132
external to insulating enclosure
14
. Chemical reagents are introduced from a supply vessel
134
into chemical reaction chamber
132
and react with the products from combustion of the waste gas as the products cool or after they are cooled. Depleted exhaust gases are vented to atmosphere through vent
136
and the reaction products are continually removed after reaction through take of
138
.
Gas flare
10
can be reconfigured so that a section of outlet
90
and a section of inlet
32
together serve as a heat exchanger
140
, as illustrated schematically in FIG.
4
. The heat of the hot exhaust from outlet
90
is used to pre-heat the mixture of air and waste gases fed through inlet
32
into primary combustion chamber
34
, thereby improving the overall thermal and operating efficiency of gas flare
10
.
In prototype development is was discovered that only high temperature materials could be used. This led to the use of ceramic in the commercial version. With the switch to ceramic the unit became one piece rather than modular, as had been the case with the original proto-type. It was also determined that better performance could be obtained when the electrical elements used as burners were spaced at intervals along each combustion chamber. The number of electrical elements used depends upon the length of the unit. With a combusion chamber thirty four inches long, three electrical elements were found to be adequate.
Care should be taken when introducing gas into the unit. The unit should be preheated in preparation for receiving the gas. There should also be circulating through the unit an abundant supply of combustion air. If gas is allowed to accummulate in the unit and is then ignited, an explosion may occur.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
Claims
- 1. A gas flare, comprising:an elongate primary combustion chamber having a first end, a second end, an inlet at the first end, an outlet at the second end and at least one primary burner disposed between the first end and the second end; at least one elongate supplementary combustion chamber having a first end, a second end, an inlet at the first end, an outlet at the second end and at least one supplementary burner disposed between the first end and the second end, the outlet of the primary combustion chamber being coupled with the inlet of the at least one supplementary combustion chamber, such that a flow path is created for waste gas past the at least one primary burner in the primary combustion chamber and past the at least one supplementary burner in the at least one supplementary combustion chamber, whereby the waste gas is subjected to multiple burner exposure, each of the at least one supplementary combustion chambers having a supplementary source of combustion air.
- 2. The gas flare as defined in claim 1, wherein the at least one primary burner and each of the at least one supplementary burners is an electric heating element.
- 3. The gas flare as defined in claim 1, wherein the at least one supplementary combustion chamber is stacked on top of the primary combustion chamber.
- 4. A gas flare, comprising:an elongate primary combustion chamber having a first end, a second end, an inlet at the first end, an outlet at the second end and at least one primary burner disposed between the first end and the second end; at least one elongate supplementary combustion chamber having a first end, a second end, an inlet at the first end, an outlet at the second end and at least one supplementary burner disposed between the first end and the second end, the outlet of the primary combustion chamber being coupled with the inlet of the at least one supplementary combustion chamber, such that a flow path is created for waste gas past the at least one primary burner in the primary combustion chamber and past the at least one supplementary burner in the at least one supplementary combustion chamber, whereby the waste gas is subjected to multiple burner exposure, wherein the outlet of the at least one supplementary combustion chamber is connected to a cooling and chemical reaction chamber, whereby chemicals are introduced into and react with the waste gas as it cools.
- 5. A gas flare, comprising:a body having several levels, including: an elongate primary combustion chamber positioned on a first level, the primary combustion chamber having a first end, a second end, and inlet at the first end, an outlet at the second end and a primary burner assembly in the form of electric heating elements disposed between the first end and the second end; a elongate first supplementary combustion chamber positioned on a second level above the first level, the first supplementary combustion chamber having a first end, a second end, an inlet at the first end, an outlet at the second end and a first supplementary burner assembly in the form of electric heating elements disposed between the first end and the second end, the outlet of the primary combustion chamber being coupled with the inlet of the first supplementary combustion chamber; a elongate first supplementary combustion chamber positioned on a third level above the second level, the second supplementary combustion chamber having a first end, a second end, an inlet at the first end, an outlet at the second end and a second supplementary burner assembly in the form of an electric heating element disposed between the first end and the second end, the outlet of the first supplementary combustion chamber being coupled with the inlet of the second supplementary combustion chamber, such that a flow path is created for waste gas past the primary burner assembly in the primary combustion chamber, past the first supplementary burner assembly in the first supplementary combustion chamber and past the second supplementary burner assembly in the second supplementary combustion chamber, whereby the waste gas is subjected to multiple burner exposure, each of the fist supplementary combustion chamber and the second supplementary combustion chambers have a supplementary source of combustion air.
- 6. The gas flare as defined in claim 5, wherein the outlet of the second supplementary combustion chamber is connected to a cooling and chemical reaction chamber, whereby chemicals are introduced into and react with the waste gas as it cools.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2292199 |
Dec 1999 |
CA |
|
US Referenced Citations (15)
Foreign Referenced Citations (1)
Number |
Date |
Country |
5-332523 |
Dec 1993 |
JP |