U.S. patent application number 15/730183 was filed with the patent office on 2018-02-01 for apparatus, systems, and methods for pre-heating feedstock to a melter using melter exhaust.
The applicant listed for this patent is JOHNS MANVILLE. Invention is credited to Aaron Morgan Huber.
Application Number | 20180029915 15/730183 |
Document ID | / |
Family ID | 56853546 |
Filed Date | 2018-02-01 |
United States Patent
Application |
20180029915 |
Kind Code |
A1 |
Huber; Aaron Morgan |
February 1, 2018 |
APPARATUS, SYSTEMS, AND METHODS FOR PRE-HEATING FEEDSTOCK TO A
MELTER USING MELTER EXHAUST
Abstract
Feedstock supply structure apparatus, including an exhaust
conduit fluidly and mechanically connectable to a structure
defining a melting chamber, the exhaust conduit positioned at an
angle to vertical ranging from 0 to about 90 degrees. The exhaust
conduit may include a heat exchange substructure, or the conduit
itself may serve as a heat exchanger. A feedstock supply structure
fluidly connected to the exhaust conduit. Systems include a
structure defining a melting chamber and an exhaust conduit fluidly
connected to the structure. The exhaust conduit includes a heat
exchange substructure for preheating the feedstock. Methods include
supplying a granular or pellet-sized feedstock to the melter
exhaust conduit, the exhaust conduit including the heat exchange
substructure, and preheating the feedstock by indirect or direct
contact with melter exhaust in the heat exchange substructure.
Inventors: |
Huber; Aaron Morgan; (Castle
Rock, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JOHNS MANVILLE |
Denver |
CO |
US |
|
|
Family ID: |
56853546 |
Appl. No.: |
15/730183 |
Filed: |
October 11, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14844198 |
Sep 3, 2015 |
9815726 |
|
|
15730183 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C03B 3/023 20130101;
C03B 5/2356 20130101; C03B 2211/22 20130101 |
International
Class: |
C03B 3/02 20060101
C03B003/02; C03B 5/235 20060101 C03B005/235 |
Claims
1. A system comprising (consisting essentially of, consisting of):
(a) a structure defining a melting chamber; (b) one or more exhaust
conduits fluidly connected to the structure defining the melting
chamber and comprising a heat exchange substructure, the one or
more exhaust conduits positioned at an angle to vertical ranging
from 0 to about 90 degrees; (c) a feedstock supply structure
fluidly connected to the one or more exhaust conduits.
2. The system in accordance with claim 1 wherein the angle ranges
from about 10 to about 75 degrees.
3. The system in accordance with claim 1 wherein the angle is
greater than 80 degrees, and the feedstock supply structure
includes a feedstock advancing mechanism.
4. The system in accordance with claim 1 wherein the feedstock
supply structure and the heat exchange substructure are configured
to allow feedstock having granule or pellet size feedstock to flow
into the melting chamber and allow indirect heat exchange from at
least some of the exhaust flowing from the melting chamber to at
least some of the feedstock.
5. The system in accordance with claim 4 wherein the size of the
feedstock granules or pellets ranges from about 1 cm to about 10 cm
(or from about 1-5 cm, or from about 1-2 cm).
6. The system in accordance with claim 1 wherein at least one of
the one or more exhaust conduits is at an angle of 0 degrees to
vertical, and the feedstock supply structure comprises; a
horizontal feedstock supply conduit fluidly connected to the at
least one of the one or more exhaust conduits above the heat
exchange substructure, a feedstock supply container fluidly
connected to the horizontal feedstock supply conduit, and a
feedstock advancing mechanism disposed in the horizontal feedstock
supply conduit, the feedstock advancing mechanism in turn connected
to a prime mover.
7. The system in accordance with claim 6 wherein the heat exchange
substructure comprises one or more internal structures (baffles,
distributor plates, grids) for causing a tortuous flow path for the
feedstock and for the exhaust.
8. The system in accordance with claim 1 wherein at least one of
the one or more exhaust conduits comprises the first vertical
exhaust conduit comprising the heat exchange substructure fluidly
connecting the melting chamber to a first 3-way flow connector, the
first 3-way flow connector fluidly connecting the first vertical
exhaust conduit comprising the heat exchange substructure with a
second vertical exhaust conduit and an angled exhaust conduit, the
angled exhaust conduit being at an angle ranging from about 25 to
about 60 degrees to vertical, the angled exhaust conduit fluidly
connected to a second 3-way flow connector, the second 3-way flow
connector fluidly connecting the angled exhaust conduit to a third
vertical exhaust conduit and with an angled feedstock supply
conduit, and the feedstock supply structure comprises: a feedstock
supply container fluidly connected to the angled feedstock supply
conduit, and the first 3-way flow connector or the second vertical
exhaust conduit comprising a damper mechanism disposed therein for
diverting at least a portion of the exhaust to the first angled
exhaust conduit, the damper mechanism in turn connected to a prime
mover.
9. The system in accordance with claim 8 comprising an auxiliary
exhaust connection between the second and third vertical exhaust
conduits.
10. The system in accordance with claim 1 wherein at least one of
the one or more exhaust conduits comprises an angled exhaust
conduit serving as the heat exchange substructure, the angled
exhaust conduit fluidly connecting the melter chamber to a 3-way
flow connector, the 3-way flow connector fluidly connecting the
angled exhaust conduit with an angled feedstock supply conduit and
to a vertical exhaust conduit, the feedstock supply structure
comprises a feedstock supply container fluidly connected to the
angled feedstock supply conduit.
11. The system in accordance with claim 10 comprising a vent
conduit fluidly connecting the feedstock supply container to the
second vertical exhaust conduit.
12. A feedstock supply structure apparatus comprising: (a) an
exhaust conduit fluidly and mechanically connectable to a structure
defining a melting chamber, the exhaust conduit positioned at an
angle to vertical ranging from 0 to about 90 degrees; (b) the
exhaust conduit comprising a heat exchange substructure; and (c) a
feedstock supply structure fluidly connected to the exhaust
conduit.
13. The feedstock supply structure apparatus in accordance with
claim 12 wherein the exhaust conduit is at an angle of 0 degrees to
vertical, and the feedstock supply structure comprises; a
horizontal feedstock supply conduit fluidly connected to the
exhaust conduit above the heat exchange substructure, a feedstock
supply container fluidly connected to the horizontal feedstock
supply conduit, and a feedstock advancing mechanism disposed in the
horizontal feedstock supply conduit, the feedstock advancing
mechanism in turn connected to a prime mover.
14. A method comprising: (a) supplying a granular or pellet-sized
feedstock to an exhaust conduit from a melter, the exhaust conduit
comprising a heat exchange substructure; (b) preheating the
granular or pellet-sized feedstock by indirect contact with melter
exhaust in the heat exchange substructure.
15. A method comprising: (a) supplying a granular or pellet-sized
feedstock to an exhaust conduit from a melter, the exhaust conduit
comprising a heat exchange substructure; (b) preheating the
granular or pellet-sized feedstock by direct contact with melter
exhaust in the heat exchange substructure.
16. A method comprising: (a) supplying a granular or pellet-sized
feedstock to an exhaust conduit from a melter, the exhaust conduit
serving as a heat exchange substructure; (b) preheating the
granular or pellet-sized feedstock by direct contact with melter
exhaust in the exhaust conduit.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a division of prior pending U.S.
application Ser. No. 14/844,198 filed Sep. 3, 2015. The entire
disclosure of this application is hereby incorporated by reference,
for all purposes, as if fully set forth herein.
BACKGROUND INFORMATION
Technical Field
[0002] The present disclosure relates generally to the field of
combustion melters and apparatus, and methods of use, and more
specifically to submerged and conventional combustion melters, and
methods of their use, particularly for melting glass-forming
materials, mineral wool forming materials, and other non-metallic
inorganic materials.
Background Art
[0003] A submerged combustion melter (SCM) may be employed to melt
glass batch and/or waste glass materials to produce molten glass,
or may melt mineral wool feedstock to make mineral or rock wool, by
passing oxygen, oxygen-enriched mixtures, or air along with a
liquid, gaseous and/or particulate fuel (some of which may be in
one or more of the feedstock materials), directly into a molten
pool of glass or other material, usually through burners submerged
in a turbulent melt pool. The introduction of high flow rates of
products of combustion of the oxidant and fuel into the molten
material, and the expansion of the gases during submerged
combustion (SC), cause rapid melting of the feedstock and much
turbulence and foaming. Conventional melters operate primarily by
combusting fuel and oxidant above the molten pol of melt, and are
very laminar in flow characteristics compared to SCMs. While most
of the present disclosure discusses SCM, the disclosure is
pertinent to conventional melters as well.
[0004] Oxy-fuel burners and technologies provide high heat transfer
rates, fuel consumption reductions (energy savings), reduced volume
of flue gas, and reduction of pollutants emission, such as oxides
of nitrogen (NOx), carbon monoxide (CO), and particulates. Despite
the reduction of the flue gas volume that the substitution of
combustion with air by combustion with pure oxygen or
oxygen-enriched air yields, a significant amount of energy is lost
in the flue gas (also referred to herein as exhaust or exhaust
gases), especially for high temperature processes. For example, in
an oxy-fuel fired glass furnace where all the fuel is combusted
with pure oxygen, and for which the temperature of the flue gas at
the furnace exhaust is of the order of 1350.degree. C., typically
30% to 40% of the energy released by the combustion of the fuel is
lost in the flue gas. It would be advantageous to recover some of
the energy available from the flue gas in order to improve the
economics of operating an oxy-fuel fired furnace, whether SCM or
conventional melter.
[0005] One technique consists in using the energy available in the
flue gas to preheat and/or dry out the raw materials before loading
them into the furnace. In the case of glass melting, the raw
materials may comprise recycled glass, commonly referred to as
cullet, and other minerals and chemicals in a pulverized form
referred to as batch materials that have a relatively high water
content. The energy exchange between the flue gas and the raw
materials may be carried out in a batch/cullet preheater. Such
devices are commonly available, for example from Zippe Inc. of
Wertheim, Germany. Experience shows that this technology is
difficult to operate when the batch represents more than 50% of the
raw materials because of a tendency to plug. This limits the
applicability of the technique to a limited number of glass melting
operations that use a large fraction of cullet. Another drawback of
this technique (according to the known art) is that the inlet
temperature of the flue gas in the materials preheater must be
generally kept lower than 600.degree. C. In the case of an oxy-fuel
fired furnace where the flue gas is produced at a temperature
higher than 1000.degree. C., one reference (U.S. Pat. No.
6,250,916) discloses that cooling of the flue gas prior to the
materials preheater would be required. This would be
counterproductive.
[0006] One low-cost non-metallic inorganic material being used to
make inorganic fibers is basalt rock, sometimes referred to as lava
rock. US20120104306 discloses a method for manufacturing basalt
filament, comprising the steps of grinding basalt rock as a
material, washing a resultant ground rock, melting the ground rock
that has been washed, transforming a molten product into fiber, and
drawing the fiber in an aligned manner, and winding it. The
temperature of the molten product in the melting step is 1400 to
1650.degree. C., and log .eta. is 2.15 to 2.35 dPas and more
preferably 2.2 to 2.3 dPas, where .eta. is the viscosity of the
molten product. The size of basalt rock may be on the order of
several mm to several dozens of mm, or several .mu.m to several
dozens of mm, according to this reference.
[0007] It would be an advanced in the melter art, and in particular
the submerged combustion melter art, to improve energy usage while
avoiding the heat loss from the exhaust while melting granular or
pellets-size material (much larger than several dozens of mm), and
prolong the run-length or campaign length of submerged combustion
melters.
SUMMARY
[0008] In accordance with the present disclosure, submerged
combustion (SC) burner panels are described that may reduce or
eliminate problems with known SC burners, melters, and methods of
using the melters to produce molten glass and other non-metallic
inorganic materials, such as rock wool and mineral wool.
[0009] One aspect of this disclosure is a system comprising (or
consisting essentially of, or consisting of): [0010] (a) a
structure defining a melting chamber; [0011] (b) one or more
exhaust conduits fluidly connected to the structure defining the
melting chamber and comprising a heat exchange substructure, the
one or more exhaust conduits positioned at an angle to vertical
ranging from 0 to about 90 degrees (or from about 10 to about 75
degrees, or from about 25 to about 60 degrees); and [0012] (c) a
feedstock supply structure fluidly connected to the one or more
exhaust conduits.
[0013] Another aspect of this disclosure is a feedstock supply
structure apparatus comprising (or consisting essentially of, or
consisting of): [0014] (a) an exhaust conduit fluidly and
mechanically connectable to a structure defining a melting chamber,
the exhaust conduit positioned at an angle to vertical ranging from
0 to about 90 degrees; [0015] (b) the exhaust conduit comprising a
heat exchange substructure; and [0016] (c) a feedstock supply
structure fluidly connected to the exhaust conduit.
[0017] Another aspect of this disclosure is a method comprising (or
consisting essentially of, or consisting of): [0018] (a) supplying
a granular or pellet-sized feedstock to an exhaust conduit from a
melter, the exhaust conduit comprising a heat exchange
substructure; [0019] (b) preheating the granular or pellet-sized
feedstock by indirect or direct contact with melter exhaust in the
heat exchange substructure.
[0020] Other system, apparatus, and method embodiments, such as
methods of producing molten non-metallic inorganic materials such
as molten glass or molten rock, in conventional melters and SCMs,
are considered aspects of this disclosure. Certain methods within
the disclosure include methods wherein the fuel may be a
substantially gaseous fuel selected from the group consisting of
methane, natural gas, liquefied natural gas, propane, carbon
monoxide, hydrogen, steam-reformed natural gas, atomized oil or
mixtures thereof, and the oxidant may be an oxygen stream
comprising at least 90 mole percent oxygen.
[0021] Systems, apparatus, and methods of the disclosure will
become more apparent upon review of the brief description of the
drawings, the detailed description of the disclosure, and the
claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The manner in which the objectives of the disclosure and
other desirable characteristics can be obtained is explained in the
following description and attached drawings in which:
[0023] FIGS. 1, 2, and 3 are schematic side elevation views,
partially in cross-section, of three system and method embodiments
in accordance with the present disclosure;
[0024] FIGS. 4A and 4B are schematic side cross-sectional and axial
cross-sectional views, respectively, of one indirect heat exchange
embodiment in accordance with the present disclosure; and
[0025] FIGS. 5A and 5B are schematic side cross-sectional and axial
cross-sectional views, respectively, of another indirect heat
exchange embodiment in accordance with the present disclosure.
[0026] It is to be noted, however, that the appended drawings are
schematic in nature, may not be to scale, and illustrate only
typical embodiments of this disclosure and are therefore not to be
considered limiting of its scope, for the disclosure may admit to
other equally effective embodiments.
DETAILED DESCRIPTION
[0027] In the following description, numerous details are set forth
to provide an understanding of the disclosed systems, apparatus,
and methods. However, it will be understood by those skilled in the
art that the systems, apparatus, and methods covered by the claims
may be practiced without these details and that numerous variations
or modifications from the specifically described embodiments may be
possible and are deemed within the claims. For example, wherever
the term "comprising" is used, embodiments and/or components where
"consisting essentially of" and "consisting of" are explicitly
disclosed herein and are part of this disclosure. All published
patent applications and patents referenced herein are hereby
explicitly incorporated herein by reference. In the event
definitions of terms in the referenced patents and applications
conflict with how those terms are defined in the present
application, the definitions for those terms that are provided in
the present application shall be deemed controlling. All
percentages herein are based on weight unless otherwise
specified.
[0028] As explained briefly in the Background, one drawback to
present melters, especially those employing oxy-fuel burners and
technologies, despite the fact that they provide high heat transfer
rates, fuel consumption reductions (energy savings), reduced volume
of flue gas, and reduction of pollutants emission, such as oxides
of nitrogen (NOx), carbon monoxide (CO), and particulates, a
significant amount of energy is lost in the flue gas (also referred
to herein as exhaust or exhaust gases), especially for high
temperature processes. For example, in an oxy-fuel fired glass
furnace where ail the fuel is combusted with pure oxygen, and for
which the temperature of the flue gas at the furnace exhaust is of
the order of 1350.degree. C., typically 30% to 40% of the energy
released by the combustion of the fuel is lost in the flue gas. The
present application is devoted to resolving this challenge by
pre-heating large size feedstock prior to that feedstock entering
the melter. As used herein, unless indicated to the contrary,
"feedstock" means pieces of porous, semi-porous, or solid rock or
other non-metallic inorganic material having a weight average
particle size ranging from about 1 cm to about 10 cm, or from about
2 to about 5 cm, or from about 1 to about 2 cm. The only upper
limit on feedstock weight average particle size is the internal
diameter of feedstock supply structure components, as described
herein, while the lower size limit is determined by angle of flow,
flow rate of feedstock, and (in those embodiments where heat
exchange is direct) flow rate of exhaust.
[0029] Various terms are used throughout this disclosure.
"Submerged" as used herein means that combustion gases emanate from
combustion burners or combustion burner panels under the level of
the molten glass; the burners or burner panels may be
floor-mounted, wall-mounted, or in melter embodiments comprising
more than one submerged combustion burner, any combination thereof
(for example, two floor mounted burner panels and one wall mounted
burner panel). Burner panels (such as described in Applicant's U.S.
patent application Ser. No. 14/838,148, filed Aug. 27, 2015 may
form part of an SCM floor and/or wall structure. In certain
embodiments one or more burner panels described herein may form the
entire floor. A "burner panel" is simply a panel equipped to emit
fuel and oxidant, or in some embodiments only one of these (for
example a burner panel may only emit fuel, while another burner
panel emits only oxidant, and vice versa). "SC" as used herein
means "submerged combustion" unless otherwise specifically noted,
and "SCM" means submerged combustion melter unless otherwise
specifically noted.
[0030] As used herein the phrase "combustion gases" as used herein
means substantially gaseous mixtures comprised primarily of
combustion products, such as oxides of carbon (such as carbon
monoxide, carbon dioxide), oxides of nitrogen, oxides of sulfur,
and water, as well as partially combusted fuel, non-combusted fuel,
and any excess oxidant. Combustion products may include liquids and
solids, for example soot and unburned liquid fuels. "Exhaust",
"melter exhaust", and "melter flue gas" are equivalent terms and
refer to a combination of combustion gases and effluent from the
feedstock being melted, such as adsorbed water, water of hydration,
CO.sub.2 liberated from CaCO.sub.3, and the like. Therefore exhaust
may comprise oxygen or other oxidants, nitrogen, combustion
products (including but not limited to, carbon dioxide, carbon
monoxide, NO.sub.x, SO.sub.x, H.sub.2S, and water), uncombusted
fuel, reaction products of melt-forming ingredients (for example,
but not limited to, basalt, sand (primarily SiO.sub.2), clay,
limestone (primarily CaCO.sub.3), burnt dolomitic lime, borax and
boric acid, and the like.
[0031] "Oxidant" as used herein includes air, gases having the same
molar concentration of oxygen as air (for example "synthetic air"),
oxygen-enriched air (air having oxygen concentration greater than
21 mole percent), and "pure" oxygen grades, such as industrial
grade oxygen, food grade oxygen, and cryogenic oxygen.
Oxygen-enriched air may have 50 mole percent or more oxygen, and in
certain embodiments may be 90 mole percent or more oxygen.
[0032] The term "fuel", according to this disclosure, means a
combustible composition comprising a major portion of, for example,
methane, natural gas, liquefied natural gas, propane, hydrogen,
steam-reformed natural gas, atomized hydrocarbon oil, combustible
powders and other flowable solids (for example coal powders, carbon
black, soot, and the like), and the like. Fuels useful in the
disclosure may comprise minor amounts of non-fuels therein,
including oxidants, for purposes such as premixing the fuel with
the oxidant, or atomizing liquid or particulate fuels. As used
herein the term "fuel" includes gaseous fuels, liquid fuels,
flowable solids, such as powdered carbon or particulate material,
waste materials, slurries, and mixtures or other combinations
thereof.
[0033] The sources of oxidant and fuel may be one or more conduits,
pipelines, storage facilities, cylinders, or, in embodiments where
the oxidant is air, ambient air. Oxygen-enriched oxidants may be
supplied from a pipeline, cylinder, storage facility, cryogenic air
separation unit, membrane permeation separator, or adsorption unit
such as a vacuum swing adsorption unit.
[0034] FIGS. 1, 2, and 3 are schematic side elevation views,
partially in cross-section, of three system and method embodiments
100, 200, and 300 in accordance with the present disclosure.
Systems, apparatus, and methods of the present disclosure aim to
solve or at least reduce the problem of energy loss as heat in
combustion melters, and even in purely electric (Joule heated)
melters. Embodiment 100 illustrated schematically in FIG. 1
includes a structure 2 (otherwise referred to herein as a melter)
defining a melting chamber 4, a plurality of SC burners 6 producing
a turbulent melt 8 of molten glass, molten rock, and the like, as
indicated by curved arrows in turbulent melt 8 in melting chamber
4. A turbulent surface 10 is illustrated as viewable in cutout
section 11. A batch feeder 12 for feeding particulates and/or
powdered batch materials (materials having weight average particle
size less than about 1 cm, or less than about 1 mm) through a batch
feed conduit 15 and valve arrangement 13, such as one or more glass
batch materials, is illustrated fluidly attached to melter 2. Batch
feed conduit 15 may be positioned at an angle .theta..sup.4 ranging
from about 25 to about 75 degrees. A melter outlet 14, system
supports 16, and plant floor 18 are illustrated schematically in
FIG. 1, as are exhaust conduit longitudinal axis L.sub.1.
[0035] During operation of embodiment 100, melter 2 and SC burners
6 produce an exhaust, indicated at arrow 20 in embodiment 100 of
FIG. 1. In previously known systems and methods, exhaust 20 would
pass up exhaust conduit 22 and much energy as heat would be wasted.
In accordance with embodiment 100 of the present disclosure, a
feedstock heat exchange substructure 24 is provided as a section of
exhaust conduit 22, substructure 24 including in embodiment 100 a
refractory lining 26 and a metal superstructure 28, the latter
possibly fluid-cooled or insulated as conditions dictate. One or
more feedstock flow diverters 30 is provided internal of
substructure 24 in embodiment 100 for effecting direct heat
exchange from exhaust 20 flowing tortuously upward to feedstock 35
flowing tortuously downward. Feedstock flow diverters 30 may for
example comprise one or more baffles, distributor plates, grids,
and the like for causing a tortuous flow path for feedstock 35 and
for exhaust 20. Feedstock flow diverters 30 may take any shape, for
example flat plates, corrugated plates, plates having a variety of
projections or protuberances therefrom such as spikes, knobs,
lumps, bumps, and the like, of a variety of sizes, or all the same
size. In certain embodiments the relative flow of feedstock and
exhaust through feedstock heat exchange substructure 24 may be
counter-current, co-current, or cross-current. Flow of feedstock
may be continuous, semi-continuous, semi-batch, or batch. For
example, in certain embodiments feedstock could flow into feedstock
heat exchange substructure 24 until feedstock heat exchange
substructure 24 is partially full or completely full of feedstock,
then the pre-heated stock may be dumped into melting chamber 4. One
way of accomplishing that may be by use of a grating at the bottom
of feedstock heat exchange substructure 24 having openings slightly
smaller than the feedstock particle size.
[0036] Referring again to FIG. 1 and embodiment 100, a feedstock
supply structure 33 is provided in embodiment 100 comprising a
horizontal feedstock supply conduit 32, one or more feedstock
supply containers 34, and a feedstock advancing mechanism 36.
Horizontal feedstock supply conduit 32 is at an angle to vertical
.theta. of about 90 degrees in embodiment 100. Feedstock advancing
mechanism 36 may be a piston, plunger, or other like component
within horizontal feedstock supply conduit 32, and may be connected
via a tie rod 38 or other feature to a prime mover 40, such as a
reciprocating engine or motor. A feedstock flow control component
60 may comprise a sliding gate device, valve, or other component
that functions to control and/or stop flow of feedstock in case of
emergency. A vent conduit 42 may be provided, allowing any exhaust
that should escape exhaust conduit 22 and travel into the feedstock
supply structure to be vented back to exhaust conduit 22. One or
more pressure relief devices (not illustrated) may also be
provided. It should be recognized that such an arrangement of
feedstock supply structure 33 (including a feedstock advancing
mechanism) may be required in other embodiments where feedstock
supply conduit 32 is not strictly horizontal, such as when angle to
vertical .theta. is less than 90 degrees, such as 85, 80, 75
degrees, or lower, depending on the feedstock composition, average
particle size, size of equipment (internal diameters) and the like.
In yet other embodiments, in addition to or in place of feedstock
advancing mechanism, a shaker device (not illustrated) may be
employed, with suitable flexible connections between components (or
no physical connection) that shakes or agitates feedstock supply
conduit 32.
[0037] Optionally, one or more auxiliary batch feeders 64 may be
provided, feeding batch or other material through an auxiliary
batch feed conduit 65 and valve 62 into exhaust conduit 22 to be
pre-heated in feedstock heat exchange substructure 24. Such
arrangement may be beneficial if feedstock heat exchange
substructure 24 is shut down for repair or renovation. Auxiliary
batch feed conduit 65 may be positioned at an angle .theta..sup.3
ranging from about 25 to about 75 degrees.
[0038] FIG. 2 illustrates another system embodiment 200 in
accordance with the present disclosure. System 200 includes a
non-submerged combustion melter 44 having a plurality of non-SC
burners 50 that combust a fuel with an oxidant above a
non-turbulent molten pool of melt 46. A non-turbulent surface 48 of
non-turbulent molten pool of melt 46 is very calm compared to the
very turbulent SC embodiment illustrated schematically in FIG. 1,
embodiment 100. Embodiment 200 comprises a primary exhaust conduit
22A having a longitudinal axis L.sub.1, an offset exhaust conduit
22B having a longitudinal axis L.sub.2, an auxiliary exhaust
conduit 22C, and an insulated exhaust conduit 22D. Feedstock supply
structure 33A includes an angled feedstock supply conduit 32
including an insulated section 54, and insulation 55. Insulated
section 54 is at an angle of .theta..sup.1 ranging from about 25 to
about 75 degrees to axis L.sub.1, and feedstock supply conduit 32
is at an angle of .theta..sup.2 ranging from about 25 to about 75
degrees to axis L.sub.2, where .theta..sup.1 and .theta..sup.2 may
be the same or different; in certain embodiments .theta..sup.1 may
be more than .theta..sup.2 (for example, .theta..sup.1 may be about
75 degrees, and .theta..sup.2 may be about 45 degrees).
[0039] Exhaust conduits 22A and 22D fluidly connect to insulated
section 54 of feedstock supply conduit 32 through a first 3-way
connector 56, while a second 3-way connector 58 fluidly connects
insulated section 54, feedstock supply conduit 32, and offset
exhaust conduit 22B. First and second 3-way connectors may be
Y-connectors, T-connectors, and the like. Feedstock 35 flows by
gravity out of feedstock supply container 34, controlled by size of
angled feedstock supply conduit 32 and angle .theta..sup.2 ranging
from about 25 to about 75 degrees, or from about 25 to about 60
degrees, and optionally by valve 60, through insulated section 54
and into heat exchange substructure 24, and finally into melting
chamber 4 of melter 44, as viewable in cutout section 11. A damper
or other flow diverter mechanism 52 is provided to divert part or
all of flow of exhaust 20 from melter 44 to flow through insulated
conduit 54 rather than through primary exhaust conduit 22A. In
embodiment 200, direct heat exchange may be provided only in heat
exchange substructure 24, if flow diverter 52 is open, or direct
heat exchange may be provided in both heat exchange substructure 24
and in insulated conduit 54, if flow diverter 52 is closed or
partially closed. Flow diverter mechanism 52 is in turn connected
to a prime mover (not illustrated) controlled for example by a
supervisory melter controller.
[0040] During operation of embodiment 200, in conduit 54 the
feedstock may be tumbling and closely packed, while in heat
exchange substructure 24 the feedstock is falling and may be less
compact, providing essentially two different heat exchange
opportunities.
[0041] It will be understood that one or more non-SC combustion
burners 50 may be replaced by SC burners; Joule heating elements
may be employed in conjunction with SC or non-SC burners, or as
complete replacements for all burners, although roof burners may be
desired for start-up.
[0042] FIG. 3 illustrates another system embodiment 300 in
accordance with the present disclosure, wherein at least one of the
one or more exhaust conduits comprises an angled, insulated exhaust
conduit 22E serving as the heat exchange substructure. The angled,
insulated exhaust conduit 22E fluidly connects melting chamber 4 to
a 3-way flow connector 56, the 3-way flow connector 56 fluidly
connecting angled, insulated exhaust conduit 22E with an angled
feedstock supply conduit 32 and to a vertical exhaust conduit 22F.
In embodiment 300, angled, insulated exhaust conduit 22E and
feedstock supply conduit 32 are each positioned at an angle of 0
ranging from about 25 to about 75 degrees to axis L of vertical
exhaust conduit 22F. Embodiment 300 may also include an exhaust
flow control mechanism 52 (damper or other component) to vary the
flow rate of exhaust through exhaust conduits 22E, 22F; for
example, it may be desired to decrease the flow of exhaust 20 in
order to provide more time for heat transfer from exhaust 20 to
feedstock 35. Similarly, embodiment 300 may include a feedstock
flow control mechanism 70 to control or completely shut off flow of
feedstock.
[0043] FIGS. 4A and 4B are schematic side cross-sectional and axial
cross-sectional views (A-A), respectively, of one indirect heat
exchange substructure embodiment 24A in accordance with the present
disclosure, including an internal plenum 80 (refractory, noble
metal, or other high-temperature material) serving to route exhaust
20 from melter 2 through a space between plenum 80 and refractory
26. Plenum 80 also serves to define a passage for feedstock 35 to
fall without directly contacting exhaust 20. A downcomer 82,
optionally angled away from the melting chamber, for example at an
angle .theta..sup.5 to vertical ranging from about 25 to about 75
degrees, may be provided to enhance the tendency of exhaust 20 to
travel up through the space between plenum 80 and refractory 26.
The cross-sectional shape of plenum 80 is illustrated schematically
in FIG. 4B as circular, but this could vary to other shapes such as
rectangular, triangular, and the like, and a plurality of plenums
80 may be provided, for example two or more conduits having
internal diameters larger than the feedstock size. The
cross-sectional shape of refractory 26 and metal superstructure 28
may also vary from rectangular as illustrated in FIG. 4B.
[0044] FIGS. 5A and 5B are schematic side cross-sectional and axial
cross-sectional views (B-B), respectively, of another indirect heat
exchange embodiment in accordance with the present disclosure. In
this embodiment an internal feedstock supply conduit 90 is
provided, which may be simply a continuation of feedstock supply
conduit 32 illustrated in embodiments 100, 200, and 300. As
illustrated schematically in FIG. 5A, internal feedstock supply
conduit may have a distal end 92 protruding in to melter 2 a short
distance I order to enhance the tendency of melter exhaust 20 to
traverse around internal feedstock supply conduit 90 as
illustrated. Due to the high temperatures experienced at the distal
end 92, distal end 92 (or a part or all of internal feedstock
conduit 90) may comprise one or more high-temperature refractory
materials or one or more noble metals. While FIG. 5B illustrates
internal feedstock conduit 90 and insulated exhaust conduit 22E as
having circular cross-sections, other shapes such as rectangular,
triangular, and the like may be employed.
[0045] Methods of the disclosure may be summarized for system
embodiment 100, 200 and 300 as follows. System 100 may be operated
by a method comprising: [0046] (a) supplying a granular or
pellet-sized feedstock to an exhaust conduit from a melter, the
exhaust conduit comprising a heat exchange substructure; [0047] (b)
preheating the granular or pellet-sized feedstock by indirect
contact with melter exhaust in the heat exchange substructure.
[0048] Other methods may comprise: [0049] (a) supplying a granular
or pellet-sized feedstock to an exhaust conduit from a melter, the
exhaust conduit comprising a heat exchange substructure; [0050] (b)
preheating the granular or pellet-sized feedstock by direct contact
with melter exhaust in the heat exchange substructure.
[0051] Yet other methods may comprise: [0052] (a) supplying a
granular or pellet-sized feedstock to an exhaust conduit from a
melter, the exhaust conduit serving as a heat exchange
substructure; [0053] (b) preheating the granular or pellet-sized
feedstock by direct contact with melter exhaust in the exhaust
conduit.
[0054] The initial raw material feedstock 35 may include any
material suitable for forming molten inorganic materials having a
weight average particle size such that most if not all of the
feedstock is not fluidized when traversing through the heat
exchange structure or exhaust conduit serving as the heat exchange
structure. Such materials may include glass precursors or other
non-metallic inorganic materials, such as, for example, limestone,
glass cullet, feldspar, basalt or other rock wool forming material,
and mixtures thereof. Typical examples of basalt that are
compositionally stable and available in large quantities are
reported in the afore-mentioned U.S. Patent Publication
2012/0104306, namely an ore having a larger amount of SiO.sub.2 (A,
for high-temperature applications) and an ore having a smaller
amount of SiO.sub.2 (B, for intermediate-temperature applications),
both of which have approximately the same amount of Al2O3. Although
ore A can be spun into fiber, the resultant basalt fiber has
heat-resistance problem at temperature ranges exceeding 750.degree.
C. Ore B, on the other hand, is associated with higher energy cost
for mass production of fiber. The basalt rock material feedstock
for use on the systems and methods of the present disclosure may be
selected from: (1) high-temperature ore (A) having substantially
the same amount of Al.sub.2O.sub.3 and a larger amount of
SiO.sub.2; (2) intermediate-temperature ore (B) having
substantially the same amount of Al.sub.2O.sub.3 and a smaller
amount of SiO.sub.2; and (3) a mixture of the high-temperature
basalt rock ore (A) and the intermediate-temperature basalt rock
ore (B).
[0055] Basalt rock (basalt ore) is an igneous rock. According to
U.S. Patent Publication 2012/0104306, major examples of the
constituent mineral include: (1) plagioclase:
Na(AlSi.sub.2O.sub.8)--Ca(Al.sub.2SiO.sub.8); (2) pyroxene: (Ca,
Mg, Fe2+, Fe3+, Al, Ti).sub.2[(Si, Al).sub.2O.sub.6]; and (3)
olivine: (Fe, Mg).sub.2SiO.sub.4. Ukrainian products are
inexpensive and good-quality.
[0056] Tables 1 and 2 (from U.S. Patent Publication 2012/0104306)
show examples of element ratios (wt. %) and the oxide-equivalent
composition ratios (wt. %) determined by ICP analysis (using an
inductively-coupled plasma spectrometer ICPV-3100 by Shimadzu
Corporation) performed on a high-temperature basalt ore (for
high-temperature applications), an intermediate-temperature basalt
ore (for intermediate-temperature applications), and a glass
consisting of 85% high-temperature ore and 15%
intermediate-temperature ore.
TABLE-US-00001 TABLE 1 Ore Ore (for Ore (for high-temp.) (for high-
intermediate- 85 wt % Ore (for temp.) temp.) intermediate-temp.)
(wt %) (wt %) 15 wt % (wt %) Si 23.5~28.8 23.5~28.5 25.0~28.8 Al
8.7~9.3 8.7~9.3 9.0~9.5 Fe 6.0~6.6 6.0~7.1 5.7~6.7 Ca 4.0~4.5
5.6~6.1 4.2~4.7 Na 2.1~2.3 1.8~2.0 2.0~2.3 K 1.4~1.8 1.2~1.5
1.4~1.9 Mg 0.1~1.6 1.4~3.0 1.5~1.7 Ti 0.4~0.6 0.5~0.7 0.4~0.6 Mn
0.1~0.2 0.1~0.2 0.1~0.2 P 0.05~0.10 0.05~0.09 0.07~0.10 B 0.02~0.08
0.01~0.06 0.03~0.10 Ba 0.03~0.05 0.03~0.05 0.09 Sr 0.02~0.04
0.02~0.04 0.02~0.05 Zr 0.01~0.04 0.01~0.04 0.01~0.03 Cr 0.01~0.03
0.01~0.03 0.01~0.03 S 0.01~0.03 0.01~0.03 0.01~0.03
TABLE-US-00002 TABLE 2 Ore Ore (for Ore (for high-temp.) (for high-
intermediate- 85 wt % Ore (for temp.) temp.) intermediate-temp.)
(wt %) (wt %) 15 wt % (wt %) SiO.sub.2 57.1~61.2 54.0~58.2
57.7~60.6 Al.sub.2O.sub.3 16.1~19.2 14.9~18.1 16.5~18.9 FeO +
Fe.sub.2O.sub.3 8.0~9.7 8.1~9.6 7.7~9.6 CaO 5.5~6.8 7.5~8.8 5.8~7.0
Na.sub.2O 2.8~3.3 2.2~2.9 2.6~3.2 K.sub.2O 1.8~2.1 1.4~1.8 1.8~2.2
MgO 0.20~2.5 1.4~4.8 0.2~2.8 TiO.sub.2 0.7~1.0 0.8~1.1 0.1~0.3 MnO
0.1~0.3 0.1~0.3 0.1~0.3 P.sub.2O.sub.5 0.1~0.3 0.1~0.3 0.1~0.3
B.sub.2O.sub.3 0.1~0.3 0.04~0.20 0.04~0.30 BaO 0.03~0.07 0.02~0.06
0.03~0.12 SrO 0.02~0.06 0.02~0.07 0.01~0.06 ZrO.sub.2 0.02~0.05
0.02~0.05 0.01~0.30 Cr.sub.2O.sub.3 0.01~0.05 0.01~0.05 0.01~0.04
SO 0.01~0.03 0.01~0.03 0.01~0.03
[0057] In embodiments wherein glass batch is used as a supplemental
feedstock, one glass composition for producing glass fibers is
"E-glass," which typically includes 52-56% SiO.sub.2, 12-16%
Al.sub.2O.sub.3, 0-0.8% Fe.sub.2O.sub.3, 16-25% CaO, 0-6% MgO,
0-10% B.sub.2O.sub.3, 0-2% Na.sub.2O+K.sub.2O, 0-1.5% TiO.sub.2 and
0-1% F.sub.2. Other glass batch compositions may be used, such as
those described in Applicant's published U.S. application
2008-0276652A1.
[0058] As noted herein, submerged combustion burners and burner
panels may produce violent turbulence of the molten inorganic
material in the SCM and may result in sloshing of molten material,
pulsing of combustion burners, popping of large bubbles above
submerged burners, ejection of molten material from the melt
against the walls and ceiling of melter, and the like. Frequently,
one or more of these phenomena may result in undesirably short life
of temperature sensors and other components used to monitor a
submerged combustion melter's operation, making monitoring
difficult, and use of signals from these sensors for melter control
all but impossible for more than a limited time period. Processes
and systems of the present disclosure may include indirect
measurement of melt temperature in the melter itself, as disclosed
in Applicant's U.S. Pat. No. 9,096,453, using one or more
thermocouples for monitoring and/or control of the melter, for
example using a controller. A signal may be transmitted by wire or
wirelessly from a thermocouple to a controller, which may control
the melter by adjusting any number of parameters, for example feed
rate of feeder 658 may be adjusted through a signal, and one or
more of fuel and/or oxidant conduits 24, 22 may be adjusted via a
signal, it being understood that suitable transmitters and
actuators, such as valves and the like, are not illustrated for
clarity.
[0059] Melter apparatus in accordance with the present disclosure
may also comprise one or more wall-mounted submerged combustion
burners, and/or one or more roof-mounted burners (not illustrated).
Roof-mounted burners may be useful to pre-heat the melter apparatus
melting zone, and serve as ignition sources for one or more
submerged combustion burners and/or burner panels. Melter apparatus
having only wall-mounted, submerged-combustion burners or burner
panels are also considered within the present disclosure.
Roof-mounted burners may be oxy-fuel burners, but as they are only
used in certain situations, are more likely to be air/fuel burners.
Most often they would be shut-off after pre-heating the melter
and/or after starting one or more submerged combustion burners. In
certain embodiments, if there is a possibility of carryover of
batch particles to the exhaust, one or more roof-mounted burners
could be used to form a curtain to prevent particulate carryover.
In certain embodiments, all submerged combustion burners and burner
panels may be oxy/fuel burners or oxy-fuel burner panels (where
"oxy" means oxygen, or oxygen-enriched air, as described earlier),
but this is not necessarily so in all embodiments; some or all of
the submerged combustion burners or burner panels may be air/fuel
burners. Furthermore, heating may be supplemented by electrical
heating in certain embodiments, in certain melter zones.
[0060] Certain system embodiment may comprise burner panels as
described in Applicant's U.S. patent application Ser. No.
14/838,148 filed Aug. 27, 2014 comprising a burner panel body and
one or more sets of concentric conduits for flow of oxidant and
fuel. Certain burner panels disclosed therein include those wherein
the outer conduit of at least some of the sets of concentric
conduits are oxidant conduits, and the at least one inner conduit
is one or more fuel conduits. Certain burner panel embodiments may
comprise non-fluid cooled or fluid-cooled protective members
comprising one or more noble metals. Certain burner panel
embodiments may comprise non-fluid cooled or fluid-cooled
protective members consisting essentially of one or more noble
metals. Certain burner panel embodiments may comprise non-fluid
cooled or fluid-cooled protective members consisting of one or more
noble metals. Certain burner panel embodiments may comprise those
wherein the lower fluid-cooled portion and the upper non-fluid
cooled portion are positioned in layers, with the lower
fluid-cooled portion supporting the sets of conduits and the
associated protective members. Certain burner panel embodiments may
comprise those wherein the non-fluid cooled protective member is a
shaped annular disk having a through passage, the through passage
of the shaped annular disk having an internal diameter
substantially equal to but not larger than an internal diameter of
the outer conduit. Certain burner panel embodiments may comprise
those wherein an internal surface of the through passage of the
shaped annular disk and a portion of a top surface of the shaped
annular disk are not engulfed by the fluid-cooled or
non-fluid-cooled portions of the panel body. Certain combustion
burner panels may comprise a panel body having a first major
surface defined by a lower fluid-cooled portion of the panel body,
and a second major surface defined by an upper non-fluid cooled
portion of the panel body, the panel body having at least one
through passage extending from the first to the second major
surface, the through passage diameter being greater in the lower
fluid-cooled portion than in the upper non-fluid cooled portion,
the panel body supporting at least one set of substantially
concentric at least one inner conduit and an outer conduit, each
conduit comprising proximal and distal ends, the at least one inner
conduit forming a primary passage and the outer conduit forming a
secondary passage between the outer conduit and the at least one
inner conduit; and (b) a fluid-cooled protective member associated
with each set and having connections for coolant fluid supply and
return, each fluid-cooled protective member positioned adjacent at
least a portion of the circumference of the outer conduit between
the proximal and distal ends thereof at approximately a position of
the fluid-cooled portion of the panel body. Certain burner panel
embodiments may comprise those wherein each fluid-cooled protective
member is a fluid-cooled collar having an internal diameter about
the same as an external diameter of the outer conduit, the
fluid-cooled collar having an external diameter larger than the
internal diameter. Certain burner panel embodiments may comprise a
mounting sleeve. In certain burner panel embodiments the mounting
sleeve having a diameter at least sufficient to accommodate the
external diameter of the fluid-cooled collar. In certain
embodiments, the burner panel may include only one or more fuel
conduits, or only one or more oxidant conduits. These embodiments
may be paired with other panels supplying fuel or oxidant (as the
case might be), the pair resulting in combustion of the fuel from
one panel with the oxidant from the other panel. In certain
embodiments the burner panel may comprise a pre-disposed layer or
layers of glass, ceramic, refractory, and/or refractory metal or
other protective material as a protective skull over the non-fluid
cooled body portion or layer. The layer or layers of protective
material may or may not be the same as the material to be melted in
the SCM.
[0061] Suitable materials for glass-contact refractory, which may
be present in SCMs and non-SC melters and downstream flow channels,
and refractory panel bodies of burner panels, include AZS
(alumina-zirconia-silica), .alpha./.beta. alumina, zirconium oxide,
chromium oxide, chrome corundum, so-called "dense chrome", and the
like. One "dense chrome" material is available from Saint Gobain
under the trade name SEFPRO, such as C1215 and C1221. Other useable
"dense chrome" materials are available from the North American
Refractories Co., Cleveland, Ohio (U.S.A.) under the trade
designations SERV 50 and SERV 95. Other suitable materials for
components that require resistance to high temperatures are fused
zirconia (ZrO.sub.2), fused cast AZS (alumina-zirconia-silica),
rebonded AZS, or fused cast alumina (Al.sub.2O.sub.3). The choice
of a particular material may be dictated by the geometry of the
apparatus, the type of material being produced, operating
temperature, burner body panel geometry, and type of glass or other
product being produced.
[0062] The term "fluid-cooled" means use of a coolant fluid (heat
transfer fluid) to transfer heat away from the component in
question (such as structural walls of an SCM), either by the fluid
traveling through the refractory of the panel, through conduits
positioned in or adjacent the refractory of the panel, and the
like, and does not include natural heat transfer that may occur by
ambient air flowing past the panel, or ambient air merely existing
adjacent a panel. For example, portions of the heat transfer
substructure nearest the melter, distal portion of feedstock supply
conduits, and the like may require fluid cooling. Heat transfer
fluids may be any gaseous, liquid, slurry, or some combination of
gaseous, liquid, and slurry compositions that functions or is
capable of being modified to function as a heat transfer fluid.
Gaseous heat transfer fluids may be selected from air, including
ambient air and treated air (for example, air treated to remove
moisture), inorganic gases, such as nitrogen, argon, and helium,
organic gases such as fluoro-, chloro- and chlorofluorocarbons,
including perfluorinated versions, such as tetrafluoromethane, and
hexafluoroethane, and tetrafluoroethylene, and the like, and
mixtures of inert gases with small portions of non-inert gases,
such as hydrogen. Heat transfer liquids and slurries may be
selected from liquids and slurries that may be organic, inorganic,
or some combination thereof, for example, water, salt solutions,
glycol solutions, oils and the like. Other possible heat transfer
fluids include steam (if cooler than the expected glass melt
temperature), carbon dioxide, or mixtures thereof with nitrogen.
Heat transfer fluids may be compositions comprising both gas and
liquid phases, such as the higher chlorofluorocarbons. Certain SCMs
and method embodiments of this disclosure may include fluid-cooled
panels such as disclosed in Applicant's U.S. Pat. No.
8,769,992.
[0063] In certain SCMs, one or more fuel and/or oxidant conduits in
the SCM and/or flow channel(s) downstream thereof may be adjustable
with respect to direction of flow of the fuel or oxidant or both.
Adjustment may be via automatic, semi-automatic, or manual control.
Certain system embodiments may comprise a mount that mounts the
fuel or oxidant conduit in a burner panel of the SCM and/or flow
channel comprising a refractory, or refractory-lined ball joint.
Other mounts may comprise rails mounted in slots in the wall or
roof. In yet other embodiments the fuel and/or oxidant conduits may
be mounted outside of the melter or channel, on supports that allow
adjustment of the fuel or oxidant flow direction. Useable supports
include those comprising ball joints, cradles, rails, and the
like.
[0064] Certain systems and processes of the present disclosure may
utilize measurement and control schemes such as described in
Applicant's U.S. Pat. No. 9,096,453, and/or feed batch
densification systems and methods as described in Applicant's U.S.
Pat. No. 9,643,869. Certain SCMs and processes of the present
disclosure may utilize devices for delivery of treating
compositions such as disclosed in Applicant's U.S. Pat. No.
8,973,405.
[0065] Certain systems, apparatus, and method embodiments of this
disclosure may be controlled by one or more controllers. For
example, combustion (flame) temperature may be controlled by
monitoring one or more parameters selected from velocity of the
fuel, velocity of the primary oxidant, mass and/or volume flow rate
of the fuel, mass and/or volume flow rate of the primary oxidant,
energy content of the fuel, temperature of the fuel as it enters
burners or burner panels, temperature of the primary oxidant as it
enters burners or burner panels, temperature of the effluent
(exhaust) at melter exhaust exit, pressure of the primary oxidant
entering burners or burner panels, humidity of the oxidant, burner
or burner panel geometry, combustion ratio, and combinations
thereof. Certain SCMs and processes of this disclosure may also
measure and/or monitor feed rate of batch or other feedstock
materials, such as rock wool or mineral wool feedstock, glass
batch, cullet, mat or wound roving and treatment compositions, mass
of feed, and use these measurements for control purposes. Flow
diverter positions may be adjusted or controlled to increase heat
transfer in heat transfer substructures and exhaust conduits.
[0066] Various conduits, such as feedstock supply conduits, exhaust
conduits, oxidant and fuel conduits of burners or burner panels of
the present disclosure may be comprised of metal, ceramic,
ceramic-lined metal, or combination thereof. Suitable metals
include carbon steels, stainless steels, for example, but not
limited to, 306 and 316 steel, as well as titanium alloys, aluminum
alloys, and the like. High-strength materials like C-110 and C-125
metallurgies that are NACE qualified may be employed for burner
body components. (As used herein, "NACE" refers to the corrosion
prevention organization formerly known as the National Association
of Corrosion Engineers, now operating under the name NACE
International, Houston, Tex.) Use of high strength steel and other
high strength materials may significantly reduce the conduit wall
thickness required, reducing weight of the conduits and/or space
required for conduits. In certain locations, precious metals and/or
noble metals (or alloys) may be used for portions or all of these
conduits. Noble metals and/or other exotic corrosion and/or
fatigue-resistant materials such as platinum (Pt), ruthenium (Ru),
rhodium (Rh), palladium (Pd), silver (Ag), osmium (Os), iridium
(Ir), and gold (Au); alloys of two or more noble metals; and alloys
of one or more noble metals with a base metal may be employed. In
certain embodiments a protective layer or layers or components may
comprise an 80 wt. percent platinum/20 wt. percent rhodium alloy
attached to a base metal using brazing, welding or soldering of
certain regions, as further explained in Applicant's pending U.S.
patent application Ser. No. 14/778,206.
[0067] When in alloyed form, alloys of two or more noble metals may
have any range of noble metals. For example, alloys of two noble
metals may have a range of about 0.01 to about 99.99 percent of a
first noble metal and 99.99 to 0.01 percent of a second noble
metal. Any and all ranges in between 0 and 99.99 percent first
noble metal and 99.99 and 0 percent second noble metal are
considered within the present disclosure, including 0 to about 99
percent of first noble metal; 0 to about 98 percent; 0 to about 97
percent; 0 to about 96; 0 to about 95; 0 to about 90; 0 to about
80; 0 to about 75; 0 to about 70; 0 to about 65; 0 to about 60; 0
to about 55; 0 to about 50; 0 to about 45, 0 to about 40; 0 to
about 35; 0 to about 30; 0 to about 25; 0 to about 20; 0 to about
19; 0 to about 18; 0 to about 17; 0 to about 16; 0 to about 15; 0
to about 14; 0 to about 13; 0 to about 12; 0 to about 11; 0 to
about 10; 0 to about 9; 0 to about 8; 0 to about 7; 0 to about 6; 0
to about 5; 0 to about 4; 0 to about 3; 0 to about 2; 0 to about 1
; and 0 to about 0.5 percent of a first noble metal; with the
balance comprising a second noble metal, or consisting essentially
of (or consisting of) a second noble metal (for example with one or
more base metals present at no more than about 10 percent, or no
more than about 9 percent base metal, or no more than about 8, or
about 7, or about 6, or about 5, or about 4, or about 3, or about
2, or no more than about 1 percent base metal).
[0068] In certain noble metal alloy embodiments comprising three or
more noble metals, the percentages of each individual noble metal
may range from equal amounts of all noble metals in the composition
(about 33.33 percent of each), to compositions comprising, or
consisting essentially of, or consisting of 0.01 percent of a first
noble metal, 0.01 percent of a second noble metal, and 99.98
percent of a third noble metal. Any and all ranges in between about
33.33 percent of each, and 0.01 percent of a first noble metal,
0.01 percent of a second noble metal, and 99.98 percent of a third
noble metal, are considered within the present disclosure.
[0069] The choice of a particular material is dictated among other
parameters by the chemistry, pressure, and temperature of fuel and
oxidant used and type of melt to be produced with certain
feedstocks. The skilled artisan, having knowledge of the particular
application, pressures, temperatures, and available materials, will
be able design the most cost effective, safe, and operable heat
transfer substructures, feedstock and exhaust conduits, burners,
burner panels, and melters for each particular application without
undue experimentation.
[0070] The total quantities of fuel and oxidant used by burners or
burner panels of the present disclosure may be such that the flow
of oxygen may range from about 0.9 to about 1.2 of the theoretical
stoichiometric flow of oxygen necessary to obtain the complete
combustion of the fuel flow. Another expression of this statement
is that the combustion ratio may range from about 0.9 to about 1.2.
The amount of heat needed to be produced by combustion of fuel in
the melter (and/or Joule heating) will depend upon the efficiency
of the preheating of the feedstock in the feedstock heat exchange
substructure. The larger the amount of heat transferred to the
feedstock, the lower the heat energy required in the melter from
the fuel and/or Joule elements.
[0071] In SCMs, the velocity of the fuel in the various burners
and/or burner panel embodiments depends on the burner/burner panel
geometry used, but generally is at least about 15 meters/second
(m/s). The upper limit of fuel velocity depends primarily on the
desired penetration of flame and/or combustion products into the
glass melt and the geometry of the burner panel; if the fuel
velocity is too low, the flame temperature may be too low,
providing inadequate temperature in the melter, which is not
desired, and if the fuel flow is too high, flame and/or combustion
products might impinge on a melter wall or roof, or cause carryover
of melt into the exhaust, or be wasted, which is also not desired.
Baffles may be provided extending from the roof, and/or in the
melter exhaust conduit, such as in the heat exchange substructure,
in order to safeguard against this. Similarly, oxidant velocity
should be monitored so that flame and/or combustion products do not
impinge on an SCM wall or roof, or cause carryover of melt into the
exhaust, or be wasted. Oxidant velocities depend on fuel flow rate
and fuel velocity, but in general should not exceed about 200
ft/sec at 400 scfh flow rate.
[0072] A combustion and/or Joule heating process control scheme may
be employed. A master controller may be employed, but the
disclosure is not so limited, as any combination of controllers
could be used. The controller may be selected from PI controllers,
PID controllers (including any known or reasonably foreseeable
variations of these), and may compute a residual equal to a
difference between a measured value and a set point to produce an
output to one or more control elements. The controller may compute
the residual continuously or non-continuously. Other possible
implementations of the disclosure are those wherein the controller
comprises more specialized control strategies, such as strategies
selected from feed forward, cascade control, internal feedback
loops, model predictive control, neural networks, and Kalman
filtering techniques.
[0073] The term "control", used as a transitive verb, means to
verify or regulate by comparing with a standard or desired value.
Control may be closed loop, feedback, feed-forward, cascade, model
predictive, adaptive, heuristic and combinations thereof. The term
"controller" means a device at least capable of accepting input
from sensors and meters in real time or near-real time, and sending
commands directly to burner panel control elements, and/or to local
devices associated with burner panel control elements able to
accept commands. A controller may also be capable of accepting
input from human operators; accessing databases, such as relational
databases; sending data to and accessing data in databases, data
warehouses or data marts; and sending information to and accepting
input from a display device readable by a human. A controller may
also interface with or have integrated therewith one or more
software application modules, and may supervise interaction between
databases and one or more software application modules.
[0074] The phrase "PID controller" means a controller using
proportional, integral, and derivative features. In some cases the
derivative mode may not be used or its influence reduced
significantly so that the controller may be deemed a PI controller.
It will also be recognized by those of skill in the control art
that there are existing variations of PI and PID controllers,
depending on how the discretization is performed. These known and
foreseeable variations of PI, PID and other controllers are
considered within the disclosure.
[0075] The controller may utilize Model Predictive Control (MPC).
MPC is an advanced multivariable control method for use in multiple
input/multiple output (MIMO) systems. MPC computes a sequence of
manipulated variable adjustments in order to optimise the future
behavior of the process in question. It may be difficult to
explicitly state stability of an MPC control scheme, and in certain
embodiments of the present disclosure it may be necessary to use
nonlinear MPC. In so-called advanced control of various systems,
PID control may be used on strong mono-variable loops with few or
nonproblematic interactions, while one or more networks of MPC
might be used, or other multivariable control structures, for
strong interconnected loops. Furthermore, computing time
considerations may be a limiting factor. Some embodiments may
employ nonlinear MPC.
[0076] A feed forward algorithm, if used, will in the most general
sense be task specific, meaning that it will be specially designed
to the task it is designed to solve. This specific design might be
difficult to design, but a lot is gained by using a more general
algorithm, such as a first or second order filter with a given gain
and time constants.
[0077] Although only a few exemplary embodiments of this disclosure
have been described in detail above, those skilled in the art will
readily appreciate that many modifications are possible in the
exemplary embodiments without materially departing from the novel
teachings and advantages of this disclosure. Accordingly, all such
modifications are intended to be included within the scope of this
disclosure as defined in the following claims. In the claims, no
clauses are intended to be in the means-plus-function format
allowed by 35 U.S.C. .sctn. 112, Section F, unless "means for" is
explicitly recited together with an associated function. "Means
for" clauses are intended to cover the structures, materials,
and/or acts described herein as performing the recited function and
not only structural equivalents, but also equivalent
structures.
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