U.S. patent application number 12/581196 was filed with the patent office on 2011-04-21 for submerged oxy-fuel burner.
Invention is credited to Christopher MORAN.
Application Number | 20110088602 12/581196 |
Document ID | / |
Family ID | 43531021 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110088602 |
Kind Code |
A1 |
MORAN; Christopher |
April 21, 2011 |
SUBMERGED OXY-FUEL BURNER
Abstract
A burner for melting material in a furnace includes an elongated
member having a first end with a heat source, a second end with an
exhaust, and a combustion chamber disposed in the elongated member
interconnecting the first and second ends, a portion of the
elongated member between the first and second ends in contact with
the material to be melted. A method for melting the material is
also provided.
Inventors: |
MORAN; Christopher;
(University Heights, OH) |
Family ID: |
43531021 |
Appl. No.: |
12/581196 |
Filed: |
October 19, 2009 |
Current U.S.
Class: |
110/341 ;
126/343.5A; 431/354 |
Current CPC
Class: |
F23L 7/007 20130101;
Y02E 20/34 20130101; F23C 3/004 20130101; Y02E 20/344 20130101 |
Class at
Publication: |
110/341 ;
431/354; 126/343.5A |
International
Class: |
F23C 99/00 20060101
F23C099/00; F23D 14/46 20060101 F23D014/46 |
Claims
1. A burner for melting material in a furnace, comprising an
elongated member having a first end with a heat source, a second
end with an exhaust disposed remote from the material, and a
combustion chamber disposed in the elongated member interconnecting
the first and second ends, a portion of the elongated member
between the first and second ends in contact with the material to
heat and melt said material.
2. The burner of claim 1, wherein the heat source comprises a
combustion flame.
3. The burner of claim 1, wherein at least 20% of the elongated
member is in contact with the material.
4. The burner of claim 1, wherein the second end is at a higher
elevation than the first end.
5. The burner of claim 1, wherein the first and second ends are
parallel with each other.
6. The burner of claim 1, wherein the first and second ends are in
a common plane.
7. The burner of claim 1, wherein the elongated member comprises a
sidewall composition resistant to deformation when in contact with
the melted material.
8. The burner of claim 1, wherein the elongated member may be
arranged up to 90.degree. from a surface of the material to be
melted.
9. The burner of claim 1, wherein the portion of the elongated
member in contact with the material is arranged in a W-shape.
10. A furnace for melting particulate material, comprising: a
housing; a combustion chamber in the housing; a bath of material in
the combustion chamber; a burner for melting the material in the
combustion chamber, comprising an elongated member having a first
end with a heat source, a second end with an exhaust disposed
remote from the material, and a combustion chamber disposed in the
elongated member interconnecting the first and second ends, a
portion of the elongated member between the first and second ends
in contact with the material to heat and melt said material.
11. The furnace of claim 10, wherein the heat source comprises a
combustion flame.
12. The furnace of claim 10, further comprising a port disposed in
the housing through which gas is introduced into the combustion
chamber to inert an atmosphere of the combustion chamber.
13. The furnace of claim 12, wherein the gas is selected from
nitrogen and argon.
14. The furnace of claim 10, further comprising a door disposed in
the housing for providing access to the combustion chamber and the
material.
15. The furnace of claim 14, wherein the door comprises a
transparent portion for viewing the combustion chamber.
16. A method of melting particulate material in a furnace,
comprising providing a combustion flame at a first end of a hollow
elongated member, heating the elongated member with the combustion
flame, disposing at least a portion of the elongated member in the
particulate material, heating the particulate material by
conduction of the heat from the elongated member for melting said
particulate material, and exhausting combustion gases from a second
end of the elongated member disposed at a location remote from the
material.
17. The method of claim 16, wherein the exhausting of the hollow
elongated member is at an elevation higher than the combustion
flame.
18. The method of claim 16, further comprising introducing a gas
into an atmosphere proximate the particulate material, and inerting
the atmosphere with the gas.
19. The method of claim 18, wherein the gas is selected from
nitrogen and argon.
Description
[0001] The present inventive embodiments relate to burners used to
melt for example metal or alloy compositions.
[0002] Oxy-fuel burners are typically installed in a furnace or a
melting furnace in a "direct fired" manner. That is, such burners
are typically disposed such that there is no physical barrier
between the burner flame and/or products of burner combustion, with
the material to be heated or melted.
[0003] Radiant tube burners are considered "indirect fired"
burners, that is they consist of an air-fuel burner having a flame
and products of combustion which are confined to an interior of the
tube, prior to being exhausted. The tube is positioned in the
furnace such that 1) the flame and products of combustion heat the
tube from the tube interior, 2) the tube is positioned in the
furnace, but not in contact with the material to be heated or
melted, and 3) the tube's outer surfaces, heated from the inside,
radiate heat to the furnace combustion chamber atmosphere to heat
the material to be melted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] For a more complete understanding of the present
embodiments, reference may be had to the following detailed
description taken in conjunction with the drawings, of which:
[0005] FIG. 1 shows an elevation view of an oxy-fuel burner of the
present embodiment;
[0006] FIG. 2 shows an elevation view of an oxy-fuel burner of
another embodiment;
[0007] FIG. 3 shows an elevation view of an oxy-fuel burner of
still another embodiment;
[0008] FIG. 4 shows a plan view along line IV-IV of the embodiment
of FIG. 3;
[0009] FIG. 5 shows a cross-sectional view of a portion of the
oxy-fuel burner of the present embodiments;
[0010] FIG. 6 shows a melter embodiment using a plurality of the
oxy-fuel burners of for example FIG. 2;
[0011] FIG. 7 shows an elevation view of an oxy-fuel burner of
still another embodiment;
[0012] FIG. 8 shows a plan view along line VIII-VIII of the
embodiment of FIG. 7; and
[0013] FIG. 9 shows an elevation view of an oxy-fuel burner of
still another embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present embodiments provide for improved heat transfer
with respect to the products to be melted.
[0015] The embodiments of FIGS. 1-6 find use for example in
reverberatory furnaces for aluminum and/or copper melting. The
burner embodiments are disposed such that a substantial portion of
such embodiments are submerged in the molten or semi-molten metal,
while products of combustion of the burner embodiments are
exhausted so as not to contact the melt.
[0016] Referring to FIGS. 1-5, a melting furnace shown generally at
10 includes a side wall 12 constructed to provide a combustion
chamber 14 therein in which a material to be melted is disposed
which will be brought to a molten consistency as shown generally at
16 as a molten or semi-molten bath or melt.
[0017] The oxy-fuel burner or burner 18 is constructed in a tubular
shape having for example a circular cross section, with an inlet
shown generally at 22 and an outlet or exhaust shown generally at
24. An oxygen feed 26 and a fuel feed 28 are connected to a burner
portion 30 for providing a combustion flame 32 at an interior 34 of
the burner tube 18. The interior 34 of the burner tube 18 is
hollow, wherein the combustion flame 32 provides for the necessary
heat to be transferred through the burner tube 18 to contact and
heat the molten bath 16. That portion of the interior 34 exposed
only to the combustion atmosphere 14, and not the melt 16, provides
for heating of the combustion atmosphere 14 to further maintain the
molten consistency of the bath 16 after such material has been
melted. Exhaust gases from the combustion flame 32 are exhausted
through the outlet 24 as indicated by arrow 36. The exhaust 36 may
be sent to a scrubber or other capture device (neither of which is
shown).
[0018] A material from which the tube 18 is constructed is selected
from silicon carbide or a material with similar characteristics,
i.e. such material being able to withstand the characteristics of
the combustion atmosphere 14 and the bath 16. The inlet 22 and the
outlet 24 may be arranged so that they are parallel and in a common
plane.
[0019] As shown in the drawings, including FIG. 6, that portion of
the burner tube 18 in direct contact with the melt 16 provides the
heat transfer effect for melting and maintaining the molten aspect
of the bath 16. Approximately 20% to 80% of the tube 18 may be
submerged in the bath 16. The burner 18 may be arranged in the
furnace 10 up to 90.degree. from the vertical or in other words up
to 90% from a surface of the melt 16. Such a range of disposition
is shown for example when comparing FIG. 2 and FIG. 3.
[0020] Heating of the tube interior by all the embodiments of FIGS.
1-6 is by convection and radiation.
[0021] As shown in FIG. 5, for example, the quotient (Q) of
radiation and the quotient of convection is added to the quotient
of conduction to facilitate the melting which occurs in, for
example, an aluminum (Al) bath 16. The oxy-fuel flame that is
created at an interior of the burner tube 18 transfers energy to
the tube by convection and radiation. In this case, the heated
exhaust gases from the flame, made up of carbon dioxide and water
vapor, circulate inside the tube and in turn transfer energy to the
tube's inside surface. Radiation, in this case, the relatively
bright oxy-fuel flame created inside the tube, transfers energy in
the form of heat via wavelengths of light. Once energy (in the form
of heat) is transferred to the interior surface of the tube, the
energy is then transferred through the tube wall by conduction into
the bath 16. Once the outside surface of the tube is heated, energy
is then further transferred to the bath again by conduction. The
products of combustion are exhausted from the tube without coming
in contact with the product to be melted.
[0022] In FIG. 6, the burners of for example those shown in FIG. 1
or 2, are mounted in a furnace for operation. The furnace 10
includes the side wall 12 constructed to provide the combustion
chamber 14 in which is charged a metal or alloy material to be
melted into a bath 16. The burners 18 will be employed to provide
the melting of the metallic charge material. As shown in FIG. 6,
the portion of the tube 18 shown generally at 38 lies below the
surface of the molten or semi-molten bath 16.
[0023] The side wall 12 is constructed with a top 40 and a bottom
42. The top 40 and the bottom 42 are joined together with stepped
side walls 44, 46. The burners 18 selected for use in the
embodiment of FIG. 6 have the inlet portion 22 disposed at the
corresponding stepped side walls 44,46, while the outlet portion 24
containing for the exhaust 36 is provided for at the top 40. In
this manner of construction, the exhaust 36 may be released to a
scrubber or other capture device (not shown) away and elevated from
the inlet 22 of the tubular burner 18. Neither exhaust gases nor
particulate matter are introduced into the chamber 14 or the bath
16.
[0024] The heat transfer via an oxy-fuel burner in a radiant tube
submerged into the metal to be melted, is more efficient than the
conventional method wherein a direct fired air-fuel burner is
positioned in a furnace such that the flame is developed above the
metal to be heated. The improved heat transfer provided by the
burner embodiments results in more efficient and economic fuel
consumption. In addition, the products of combustion at the
interior 34 of the tubular burner 18 do not contact the molten
metal in the bath 16, thereby reducing if not eliminating oxidation
of the composition being melted in the bath 16. Further, because
combustion occurs in the tube, and not in the chamber 14 (head
space) above the bath 16, this translates into being able to use a
smaller melter or furnace 10, thereby reducing the initial capital
expense and ongoing operating expense. In addition, because the
combustion flame 32 is not provided in the combustion chamber 14 of
the furnace, the combustion chamber 14 or head space can be at a
reduced or minimum height which correspondingly translates into
reduced air infiltration to the furnace and reduced oxidation of,
for example, aluminum if such metal is being processed in the
furnace.
[0025] Since the products of combustion from the oxy-fuel flame are
not in contact with the material being melted, an inert gas can be
provided through injection port 52 into the chamber 14 above the
molten metal (the gas being confined to the chamber 14 by the walls
of the furnace), as shown by arrows 54, to protect the material
from oxidation caused by ambient air possibly leaking into the
furnace through a furnace door 50 or other openings in the furnace
structure. The inerting gas 54 can be selected from nitrogen, argon
or similar inert gas. The door 50 can include a transparent portion
of heat resistant glass for observing the combustion chamber,
material being melted, and the furnace operation. Injecting the
inert gas into the chamber 14 would not be practical or effective
in a conventional furnace because the injected nitrogen would mix
with the products of combustion from the flame, i.e., CO.sub.2,
H.sub.2O and N.sub.2 in some cases.
[0026] In FIG. 7 and FIG. 8, the tubular burner 18 is constructed
in an "L" shape. The embodiment of FIG. 9 shows the tubular burner
18 constructed in a "W" shape. In both the embodiments of FIGS.
7-9, a portion of a respective one of the tubular burners 18 is
disposed to contact the particulate material to be melted, or
submerged in the bath 16 for heating thereof, as may be done with
other of the embodiments herein. The tubular member 18 can be
formed in a myriad of different shapes, a portion of which is
submerged into the bath 16.
[0027] In addition, the embodiments of FIGS. 7-9 can be arranged
individually or in combination with each other in a furnace 10 as
shown in FIG. 6.
[0028] The burner 18 is fabricated from material that can withstand
thermal and mechanical shock, chemical reaction (fluxing) and be
able to absorb and transfer heat readily and efficiently. The
material from which a sidewall of the burner 18 is fabricated will
not deform or be structurally compromised when in contact with the
molten material in the bath 16.
[0029] A method is also provided from the embodiments of FIGS. 1-9
for melting particulate material in a furnace, the method including
providing a combustion flame in a hollow elongated member, heating
the elongated member with the combustion flame, disposing at least
a portion of the elongated member in the particulate material, and
heating the particulate material by conduction of the heat from the
elongated member for melting said particulate material.
[0030] Reduced specific energy consumption will also be realized by
the embodiments of FIGS. 1-9, in view of the reduction of energy
consumed per unit weight of metal, such as aluminum, melted.
Reduced melting times result in increased productivity and lower
production costs.
[0031] There is also realized reduced oxidized material (`dross` is
the term used within the aluminum industry, the copper industry
uses `slag`, in both cases it's metal originally charged in its
pure state, but then oxidized in the melting process) formation as
a result of no contact between the exhaust 36 and the product being
melted in the bath 16.
[0032] The present embodiments can be used with copper, tin and
magnesium furnaces or melters.
[0033] It will be understood that the embodiments described herein
are merely exemplary, and that a person skilled in the art may make
many variations and modifications without departing from the spirit
and scope of the invention. All such variations and modifications
are intended to be included within the scope of the invention as
described and claimed herein. It should be understood that
embodiments described above are not only in the alternative, but
may also be combined.
* * * * *