U.S. patent application number 12/268227 was filed with the patent office on 2009-03-12 for molten metal reactor utilizing molten metal flow for feed material and reaction product entrapment.
Invention is credited to Anthony S. Wagner.
Application Number | 20090065985 12/268227 |
Document ID | / |
Family ID | 21768869 |
Filed Date | 2009-03-12 |
United States Patent
Application |
20090065985 |
Kind Code |
A1 |
Wagner; Anthony S. |
March 12, 2009 |
MOLTEN METAL REACTOR UTILIZING MOLTEN METAL FLOW FOR FEED MATERIAL
AND REACTION PRODUCT ENTRAPMENT
Abstract
A molten metal reactor quickly entrains a feed material in the
molten reactant metal and provides the necessary contact between
the molten reactant metal and the feed material to effect the
desired chemical reduction of the feed material. The reactor
includes a unique feed structure adapted to quickly entrain the
feed material into the molten reactant metal and then transfer the
molten reactant metal, feed material, and initial reaction products
into a treatment chamber. A majority of the desired reactions occur
in the treatment chamber. Reaction products and unspent reactant
metal are directed from the treatment chamber to an output chamber
where reaction products are removed from the reactor. Unspent
reactant metal is then transferred to a heating chamber where it is
reheated for recycling through the system.
Inventors: |
Wagner; Anthony S.;
(Lakeway, TX) |
Correspondence
Address: |
THE CULBERTSON GROUP, P.C.
1114 LOST CREEK BLVD., SUITE 420
AUSTIN
TX
78746
US
|
Family ID: |
21768869 |
Appl. No.: |
12/268227 |
Filed: |
November 10, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10817461 |
Apr 2, 2004 |
7449156 |
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12268227 |
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10014976 |
Dec 11, 2001 |
6717026 |
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10817461 |
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60271825 |
Feb 27, 2001 |
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Current U.S.
Class: |
266/216 |
Current CPC
Class: |
Y02P 10/214 20151101;
C22B 7/001 20130101; Y10S 423/12 20130101; B01J 19/0066 20130101;
A62D 2203/10 20130101; Y02P 10/20 20151101; B01J 10/005 20130101;
C22B 9/00 20130101; B01J 19/02 20130101 |
Class at
Publication: |
266/216 |
International
Class: |
C21C 7/00 20060101
C21C007/00 |
Claims
1. A molten metal reactor including: (a) a treatment chamber having
a treatment chamber inlet; (b) a feed chamber having a feed chamber
outlet located adjacent to the treatment chamber inlet; (c) an
output chamber connected to an outlet of the treatment chamber to
receive molten reactant metal and reaction products from the
treatment chamber; (d) a molten reactant metal source connected to
direct molten reactant metal into the feed chamber; and (e) a feed
arrangement for releasing feed material into the feed chamber at a
point that is spaced apart from a lateral wall of the feed chamber
and adjacent to the feed chamber outlet, the feed material
comprising material to be reacted with the molten reactant
metal.
2. The molten metal reactor of claim 1 wherein the feed arrangement
includes a feed chute extending vertically through a portion of the
feed chamber.
3. The molten metal reactor of claim 1 wherein the feed arrangement
includes a feed chute having a portion that extends transversely
through the feed chamber in a direction from one lateral side of
the feed chamber toward an opposite lateral side of the feed
chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/817,461 filed Apr. 2, 2004, entitled
"Molten Metal Reactor Utilizing Molten Metal Flow for Feed Material
and Reaction Product Entrapment," which is a divisional of U.S.
patent application Ser. No. 10/014,976 filed Dec. 11, 2001,
entitled "Molten Metal Reactor Utilizing Molten Metal Flow for Feed
Material and Reaction Product Entrapment," now U.S. Pat. No.
6,717,026, which claimed priority from U.S. Provisional Patent
Application Ser. No. 60/271,825 filed Feb. 27, 2001, entitled
"Molten Metal Reactor Utilizing Molten Metal Flow for Feed Material
and Reaction Product Entrapment." The Applicant claims priority
from U.S. patent application Ser. Nos. 10/817,461 and 10/014,976
under 35 U.S.C. .sctn.120, and claims priority from U.S.
Provisional Patent Application Ser. No. 60/271,825 under 35 U.S.C.
.sctn.119(e). The entire content of each of these applications is
incorporated herein by this reference.
TECHNICAL FIELD OF THE INVENTION
[0002] This invention relates to molten metal reactors for treating
waste materials and soils contaminated with waste materials. More
particularly, the invention relates to a molten metal reactor
having an improved arrangement for entraining or entrapping feed
materials with a molten reactant metal to effect the desired
chemical reduction of the feed material. The invention encompasses
a molten metal reactor apparatus, a structure for introducing a
feed material into such a reactor, a method for treating waste
material with a molten metal, and a method for introducing a feed
material into a molten metal reactor.
BACKGROUND OF THE INVENTION
[0003] Molten metal reactors utilize a molten reactant metal to
chemically react with a feed material in order to reduce the feed
material to relatively innocuous compounds and chemical elements.
For example, U.S. Pat. No. 5,000,101 to Wagner discloses a molten
metal reactor for treating chlorinated hydrocarbons and other
dangerous organic chemicals to produce carbon, metal salts, and
gases such as nitrogen and hydrogen. U.S. Pat. No. 5,271,341 to
Wagner discloses a molten metal reactor for treating boxed
biomedical wastes which may include hazardous biological wastes
mixed with other materials and metals. The disclosed molten
reactant metal chemically reduces biological materials and other
organic materials in this waste to carbon, metal salts and
elemental gasses. Metals such as stainless steel "sharps" in the
waste dissolve or melt into the reactant metal.
[0004] A consistent issue with molten metal reactors is providing
the necessary contact between the material to be treated or
reacted, that is, the "feed material," and the molten reactant
metal. U.S. Pat. No. 5,271,341 to Wagner discloses submerging the
boxed biomedical wastes in the reactant metal bath with a
submerging or plunger structure to provide the desired contact
between the waste material and the molten reactant metal. Although
the submerging structure works well with certain types of waste
materials, such structures are not well suited for submerging other
types of materials. In particular, plunger structures are not well
suited for use in relatively high-volume waste treatment
applications in which relatively large quantities of loose or bulk
feed materials, such as contaminated soils, for example, must be
processed.
SUMMARY OF THE INVENTION
[0005] A molten metal reactor according to the present invention
quickly entrains a feed material in the molten reactant metal and
provides the necessary contact between the molten reactant metal
and the feed material to effect the desired chemical reduction of
the feed material. The quick entrainment of feed material in the
molten reactant metal is accomplished with a unique feed structure
in which the feed material is added to the reactant metal and then
quickly transferred into a treatment chamber together with the
molten reactant metal and any initial reaction products. A majority
of the desired reactions occur in the treatment chamber. Reaction
products and unspent reactant metal are preferably directed from
the treatment chamber to an output chamber where reaction products
are removed from the reactor. Unspent reactant metal is then
preferably transferred to a heating chamber where it is reheated
for recycling through the system.
[0006] According to the invention, the feed structure associated
with the reactor introduces feed material into the molten reactant
metal so that a flow of molten reactant metal immediately carries
substantially all of the feed material and any initial reaction
products into the treatment chamber. The feed material and reaction
products are then trapped in the treatment chamber preferably by
means of a suitable gravity trap structure. This combination of
substantially immediate introduction into the treatment chamber and
trapping in the treatment chamber helps ensure that the feed
material and any intermediate reaction products have sufficient
contact with the molten reactant metal to provide the desired
chemical reactions, that is, the substantially complete chemical
reduction of the feed material.
[0007] The desired contact with the reactant metal is enhanced
according to the invention by inducing a swirling or vortex flow in
the molten reactant metal in a feed chamber in which the feed
material first makes contact with the molten reactant metal. This
swirling flow may be produced in any suitable fashion, including by
directing the molten metal into the feed chamber in an off center
position, by driving the molten metal in the feed chamber with an
impeller, or both. Also, a bowl-shaped feed chamber helps
facilitate the desired swirling flow.
[0008] In order to carry the feed material and any initial reaction
products quickly into the treatment chamber in the flow of molten
reactant metal, the feed material preferably comes into contact
with the molten reactant metal in an area adjacent to an inlet to
the treatment chamber. An area "adjacent" to the treatment chamber
inlet means the area of the surface of the molten reactant metal in
the feed chamber generally nearest to the inlet of the treatment
chamber. In the form of the invention in which a swirling flow is
induced in the feed chamber, the feed material drops into the
molten reactant metal in a central area of the feed chamber, at the
center of the swirling flow or vortex, and directly above an outlet
from the feed chamber/inlet to the treatment chamber. The feed
chamber includes an outlet that at least borders the treatment
chamber inlet and more preferably comprises a common opening with
the treatment chamber inlet. By "bordering" the treatment chamber
inlet it is meant that the feed chamber outlet is in the immediate
vicinity of the treatment chamber inlet so that there is only a
small distance between any point of the feed chamber outlet and any
point of the treatment chamber inlet.
[0009] The feed material may include substantially any material or
mixture of materials suitable for treatment in a molten metal
reactor. These materials include hydrocarbons and halogenated
hydrocarbons, low and high level radioactive materials, and any
other materials that may be chemically reduced in a molten reactant
metal such as aluminum, magnesium, or combinations of these metals
together with other metals. The invention is particularly suited to
treating soils and other bulk solids which have been contaminated
with hydrocarbons, halogenated hydrocarbons, other chemically
reducible materials, radioactive materials, and metals. As used in
this disclosure and the accompanying claims a "feed material" may
comprise any of the above-described materials or combinations of
these materials.
[0010] It will be appreciated by those skilled in the art of molten
reactors that the chemical reduction reactions produced by contact
with a molten reactant metal may not immediately reduce a given
constituent compound included in a feed material. Rather, many
chemical compounds suitable for treatment with a molten reactant
metal may initially react in or with the metal to produce
intermediate reaction products. These intermediate reaction
products are then further reduced by reaction in or with the molten
reactant metal. The reactions continue in the molten reactant metal
until the reduction reactions are substantially complete, leaving
only final reaction products. Metals in the feed material compounds
are generally reduced to their elemental state, carbon is reduced
to its elemental state and goes to a gaseous state at the
temperature of the molten reactant metal, halogens form salts with
either metals from the molten reactant metal bath or with metals
contained in the feed material itself. Nitrogen and hydrogen
liberated from the reacted compounds escape from the molten metal
bath as gases. Minerals included in soil generally remain unreacted
in the molten reactant metal depending upon the makeup of the
molten reactant metal bath and its temperature, but may go to a
liquid state at the temperature of the molten metal bath.
[0011] As used in this disclosure and the accompanying claims, the
term "reaction product" is used to refer to any reaction product
produced by treatment of the feed material with the molten reactant
metal, whether the reaction product is an initial reaction product
subject to further reactions in the molten metal or a final
reaction product that is chemically stable in the molten reactant
metal. The term "reaction product" also refers to materials such as
quartz that do not chemically react with the molten reactant metal
but may be contained in soil contaminated with materials that do
react in the molten reactant metal. Thus, the term "reaction
product" means generally any material that results from any
reaction of a feed material occurring in the molten reactant
metal.
[0012] The above-described advantages and features of the
invention, along with other advantages and features, will be
apparent from the following description of the preferred
embodiments, considered along with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a diagrammatic view in section showing a molten
metal reactor embodying the principles of the invention.
[0014] FIG. 2 is a diagrammatic top plan view of the molten metal
reactor shown in FIG. 1.
[0015] FIG. 3 is a diagrammatic view in section similar to FIG. 1
but showing an alternate form of the feed arrangement.
[0016] FIG. 4 is a diagrammatic view in section similar to FIG. 3,
showing yet another alternate feed arrangement according to the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Referring particularly to FIGS. 1 and 2, a molten metal
reactor 10 embodying the principles of the invention includes
essentially four chambers including a bowl-shaped vortex or feed
chamber 11, a treatment chamber 12, an output chamber 14, and a
heating chamber 15. Each of these chambers is adapted to contain a
molten reactant metal indicated by the reference numeral 16. The
level of molten reactant metal 16 in feed chamber 11, output
chamber 14 and heating chamber 15 is indicated by the dashed line
in the respective chamber. Molten reactant metal 16 is heated to
the desired temperature in heating chamber 15 and then transferred
to feed chamber 11. From feed chamber 11, molten reactant metal 16
flows rapidly into treatment chamber 12 and then exits the
treatment chamber into output chamber 14. From output chamber 14,
molten reactant metal 16 returns to heating chamber 15 for
reheating and recycling through the reactor 10. Reaction products
are removed from reactor 10 through output chamber 14. According to
the invention, the flow of molten reactant metal from feed chamber
11 to treatment chamber 12 carries feed materials to be treated
into the treatment chamber along with substantially all reaction
products liberated from the feed material on initial contact with
the molten reactant metal. Treatment chamber 12 provides sufficient
residence time to completely react substantially all constituents
in the feed material.
[0018] FIG. 1 in particular indicates that molten metal reactor 10
includes numerous components that contain or come in contact with
molten reactant metal 16. All components that do come in contact
with the molten reactant metal are either formed from a material
which is resistant to damage from the reactant metal or coated with
such a protective material. For example, the system of chambers 11,
12, 14, and 15 may be cast from a refractory material or may be
formed from a base material which is then coated with a suitable
refractory or other chemically resistant material.
[0019] The particular reactant metal utilized in reactor 10 will
depend upon the constituents in the feed material which must be
destroyed or removed from non-hazardous constituents of the feed
material. A preferred reactant metal suitable for use in treating
many types of chemicals comprises an alloy of aluminum as disclosed
in U.S. Pat. No. 5,000,101 to Wagner, the entire content of which
is hereby incorporated in this disclosure. However, it will be
appreciated that the makeup of reactant metal 16 may be varied to
suit a particular feed material to be treated in reactor 10 and is
not limited to aluminum or aluminum alloys. Also, the temperature
of reactant metal 16 may be varied to suit the particular feed
material to be treated.
[0020] Reactor 10 is well suited for treating a number of feed
materials, including particularly contaminated soils. The soils may
be contaminated with halogenated hydrocarbons or other organic
compounds, metals, and low-level radioactive materials. Organic
compounds are reduced to liberate carbon and hydrogen. Halogens
included in organic compounds generally react with elements of the
reactant metal to form metal salts, while other materials dissolve
or melt into the molten reactant metal or release from the reactant
metal as a gas. Many radioactive materials dissolve or melt into
the reactant metal 16 where the radioactive isotopes can be
concentrated to the desired level together with radioactive
emission absorbing elements. Molten reactant metal and absorbing
metal containing the radioactive isotopes may then be drawn off to
form ingots that can safely store the radioactive isotopes.
[0021] In addition to the chamber arrangement shown in FIGS. 1 and
2, the preferred reactor 10 includes molten metal pumps 20 and 21
shown in FIG. 2, and a heater arrangement 22 associated with at
least heating chamber 15. A feed arrangement 24 is associated with
feed chamber 11 for transferring feed materials into the system.
Also, the illustrated reactor 10 includes a reaction product
removal arrangement associated with output chamber 14. The reaction
product removal arrangement is shown generally at reference numeral
25.
[0022] Referring to both FIGS. 1 and 2, feed chamber 11 includes an
outlet 28 generally at the bottom of the feed chamber. Feed
arrangement 24 is located preferably immediately over or above
outlet 28. Molten reactant metal 16 is supplied into feed chamber
11 through an inlet 29. As shown best in FIG. 2, the preferred form
of the invention has inlet 29 positioned off-center from a center
vertical axis of feed chamber 11 so that the flow of reactant
material into the chamber helps induce a swirling or vortex flow in
the feed chamber as will be described further below. Referring
still to FIG. 2, reactant metal 16 collects in a supply chamber 31
prior to flowing into feed chamber 11. This flow may be continuous
or may be on a batch basis. Where reactant metal is released into
feed chamber 11 in batches, a suitable valve (not shown) may be
associated with inlet 29. The valve may be closed to allow reactant
metal 16 to collect in supply chamber 31 then may be opened to
suddenly release the reactant metal into feed chamber 11.
[0023] It will be appreciated that it is possible to eliminate pump
21 and instead use a moveable crucible or vessel to periodically
lift molten reactant metal from heating chamber 15 and pour the
molten metal into supply chamber 31. This moveable crucible form of
the invention may be used to introduce a rapid flow of molten
reactant metal into supply chamber 31 and then into feed chamber
11.
[0024] The preferred form of the invention produces a vortex or
swirling flow in the reactant metal 16 contained in feed chamber 11
as the molten metal flows rapidly into the feed chamber and then
into treatment chamber 12. This swirling or vortex flow is
indicated by the arrows 32 in FIG. 2. In the form of the invention
shown in FIGS. 1 and 2, the off-center molten metal inlet 29,
bowl-shaped feed chamber 11, and flow rate of molten reactant metal
all combine to provide a vortex inducing arrangement. The swirling
flow of reactant metal 16 in feed chamber 11 provides a good mixing
action to rapidly incorporate or ingest the feed material into the
reactant metal. It will be appreciated that the swirling reactant
metal or vortex flow of molten reactant metal in feed chamber 11,
is not necessary to the present invention but is helpful to the
operation of the present invention. Sufficient reactant metal 16
flow rates may be produced to provide the desired waste material
entrainment without inducing a vortex in the reactant metal as it
flows from feed chamber 11 into treatment chamber 12. For example,
molten metal pump 21 may pump molten reactant metal into feed
chamber 11 at a rate on the order of fifteen thousand (15,000)
pounds per minute to produce high molten metal flow velocities from
an appropriately sized feed chamber outlet to an appropriately
sized treatment chamber inlet.
[0025] Feed arrangement 24 is adapted to transfer feed materials
into reactor 10 while minimizing the amount of oxygen entering the
reactor. Feed arrangement 24 includes an elongated chute 35 which
is preferably centered within feed chamber 11 to drop feed material
into the center of vortex or swirling flow, immediately above or
adjacent to outlet 28 from the feed chamber to treatment chamber
12. The bottom end of feed chute 35 may be referred to as a feed
material inlet into feed chamber 11. Feed chute 35 includes a purge
chamber 36 defined between an upper dump gate 38 and a lower dump
gate 39. A purge gas, in this case flue gas from heater arrangement
22 is circulated to the purge chamber through conduit 40 to purge
chamber 36 of oxygen. In operation, lower dump gate 39 is held in a
closed position sealing a bottom of purge chamber 36 while upper
dump gate 38 is held open and feed material is loaded into the
purge chamber. Once purge chamber 36 is loaded with feed material,
upper dump gate 38 is closed and purge gas is circulated through
the chamber to purge the chamber of oxygen. After the chamber is
sufficiently purged, lower dump gate 39 is opened so that the feed
material in chamber 36 drops into the molten reactant metal in feed
chamber 11. The opening of lower dump gate 39 to drop feed material
into feed chamber 11 may be coordinated with the release of molten
reactant metal 16 into the feed chamber to create the desired
swirling flow and suction effect as the molten reactant metal flows
out of the feed chamber and into treatment chamber 12.
[0026] An additional sealing conduit 42 may be associated with the
feed chute 35 to isolate the area of feed chamber 11 generally
above or adjacent to the feed chamber outlet 28. Additional sealing
conduit 42 may be used to ensure that the feed material and
reaction products flow along with the reactant metal 16 into
treatment chamber 12. It will also be noted that the top of feed
chamber 11 above the level of reactant metal 16 is sealed to the
atmosphere so that any reaction products that may remain in feed
chamber 11 are not released to the atmosphere.
[0027] Treatment chamber 12 comprises a tube or conduit extending
from the feed chamber outlet opening 28 to output chamber 14. The
preferred treatment chamber 12 also includes a gravity trap 44
having a U-shaped segment that helps prevent gases from flowing
back into feed chamber 11. Treatment chamber 12 is long enough to
provide sufficient residence time, considering the reactant metal
flow rate through the tube, to effect a substantially complete
reaction of materials that are to be destroyed in the molten metal
reactor. Residence times should be approximately three (3) minutes
to effect the desired treatment for most feed materials. The flow
velocity in treatment chamber 12 may be eight (8) feet per
minute.
[0028] In order to help maintain the reactant metal 16 at a desired
treatment temperature in treatment chamber 12, the treatment
chamber may be located immediately adjacent to heating chamber 15
so that heat from the heating chamber is transferred to material
within the treatment chamber. Also, although not shown in the
drawing, a separate heating system may be associated with the
treatment chamber 12 for maintaining the temperature of the molten
metal at a desired temperature within the treatment chamber. Any
suitable heating system may be used with treatment chamber 12
including an induction heating system using one or more
electromagnetic field induction coils positioned adjacent to the
treatment chamber.
[0029] Although a molten reactant metal level is shown by a dashed
line in FIG. 1 for chambers 11, 14 and 15, FIG. 1 does not show a
molten reactant metal level in treatment chamber 12. This should
not be taken to imply that there will be no gas phase in treatment
chamber 12. For many feed materials, a distinct gas phase of
reaction products will emerge in the top of treatment chamber 12.
However, these reaction products will be held in close proximity to
the surface of the molten reactant metal 16 in position to
facilitate further reaction of the reaction product if not fully
reduced. Gaseous reaction products will also bubble up through
molten reactant metal in the output chamber 14 to allow any further
reactions possible between the reaction products and molten
reactant metal.
[0030] A molten metal reactor within the scope of the present
invention may include a feed chamber having an outlet that is
separate and distinct from an inlet to the treatment chamber in the
reactor. However, in the preferred form of the invention shown in
FIGS. 1 and 2, feed chamber outlet 28 is common with the inlet to
treatment chamber 12, that is, the feed chamber outlet and
treatment chamber inlet comprise the same opening. The outlet from
the feed chamber according to the invention at least borders the
inlet to the treatment chamber. This proximity between feed chamber
outlet 28 and the inlet to the treatment chamber combined with the
proximity between the point at which the feed material makes
initial contact with the molten reactant metal 16 and the rapid
flow of molten reactant metal into treatment chamber 12 ensures
that the feed material and even any initial reaction products are
carried into the treatment chamber where the desired reactions may
proceed to completion. The residence time for feed materials in the
feed chamber after initial contact with the molten reactant metal
should be on the order of ten (10) seconds or less. Residence times
in this range will be considered insignificant residence times
within the scope of the following claims.
[0031] Output chamber 14 is connected to receive material exiting
an outlet 45 of treatment chamber 12. The material which flows into
outlet chamber 14 includes molten reactant metal 16 remaining after
the desired reactions with the feed material and reaction products
from the reaction of the feed material with the reactant metal. The
reaction products may include molten or gaseous metal salts,
gaseous carbon, unreacted solids such as clay particles included in
the feed material, metals from the feed material that have
dissolved or melted into the reactant metal, and other gases
liberated in the various reactions between the molten reactant
metal 16 and the feed material. These other gasses will commonly
include primarily nitrogen and hydrogen.
[0032] The reaction product removal arrangement 25 associated with
output chamber 14 includes a skimming system shown generally at
reference numeral 49 and a gas and particulate removal system shown
generally at reference numeral 50. A tapping system including
tapping line 51 with a suitable valve may also be connected to
output chamber 14 for removing heavy molten material or dissolved
material that may segregate to the bottom of the output
chamber.
[0033] Gas and particulate removal system 50 includes a collection
hood 54 at the top of output chamber 14 and an outlet conduit 55.
This outlet conduit 55 preferably leads to particulate control
equipment (PCE) 56 such as a bag house or an aqueous scrubber that
removes particulates included in, or forming from, the gases
exiting output chamber 14 through conduit 55. Flue gas from the
heater arrangement 22 may be directed into collection hood 54
through conduit 57 to enhance the flow of gases and particulates
out of the system through conduit 55. The purge gas from purge
chamber 36 may also be directed into conduit 55 to exit the system
through particulate control equipment 56.
[0034] Skimming system 49 is located at the top of output chamber
14 for removing solids and light molten materials that segregate to
the top of the reactant metal 16 in the output chamber. The
illustrated skimming system 49 includes an auger 58 which is
rotated by a suitable drive device 59 to skim material floating at
the surface of the molten reactant metal 16 to the right in FIG. 1
toward an outlet chute 60. Outlet chute 60 leads to an airlock
chamber 61 defined between an upper airlock gate 62 and a lower air
lock gate 63. In operation, lower gate 63 is closed and upper gate
is held open while auger 59 skims material through outlet chute 60
and into the airlock chamber 61 above the lower gate. After an
appropriate amount of skimmed material has collected in airlock
chamber 61, upper gate 62 is closed and lower gate 63 is opened to
allow material collected in the air lock chamber to drop into a
collection vessel 64. Positive pressure maintained in the
collection hood 54 provided by the heater flue gas helps ensure
significant amounts of oxygen does not flow into the reactor 10 as
solid material and light molten material is removed through airlock
chamber 61.
[0035] One or more deflectors such as deflector 66 may be
associated with output chamber 14 to deflect reaction products to
the desired locations within the outlet chamber and ensure that
materials do not inadvertently enter heating chamber 15. Deflectors
may also be used in outlet chamber to enhance contact with the
molten reactant metal and help ensure that the desired reactions
proceed to completion. That is, deflectors in output chamber 14 may
be arranged to cause relatively light reaction products to follow a
tortuous path through the molten reactant metal in output chamber
14 before reaching the surface of the molten reactant metal.
[0036] Heating chamber 15 comprises a chamber having a lower
portion adapted to contain a volume of reactant metal and an upper
area which is isolated from the feed chamber 11 and output chamber
14. This isolation is required in the illustrated form of the
invention to accommodate the gas fired burners 70 that make up
heating arrangement 22 used to heat the reactant metal 16 within
heating chamber 15. Exhaust gas from burners 70 exits the upper
part of the heating chamber through flue gas stack 71. A portion of
this flue gas is directed to purge chamber 36 and to collection
hood 54 as described above. Although gas fired burners are shown in
the illustrated form of the invention, other heating systems such
as an induction heating system for example, may be employed to heat
the reactant metal 16 in heating chamber 15. Of course, when
electromagnetic induction heating is used to heat reactant metal
16, a separate purge gas must be used in connection with feed purge
chamber 36 and collection hood 54 since the flue gas would not be
present.
[0037] Proper flow and circulation of molten reactant metal 16 in
reactor 10 is important to the proper operation of the reactor. In
particular, the flow of molten reactant metal 16 from feed chamber
11 to treatment chamber 12 should be at a sufficient rate to
entrain or entrap feed material and substantially any initial
reaction products, and cause these materials to be carried or swept
into the treatment chamber and ultimately into output chamber 14.
Minimum flow velocities of molten reactant metal into treatment
chamber 14 will depend upon the fluid properties of the particular
molten reactant metal and the specific gravity and other properties
of the feed material. The desired flow rates may be produced using
pumps for moving the molten reactant metal. FIG. 2 shows two molten
metal pumps in the preferred form of the invention. Pump 20 pumps
molten reactant metal 16 from output chamber 14 to heating chamber
15. Pump 21 pumps the heated or reheated molten reactant metal 16
from heating chamber 15 to feed chamber 11, in the illustrated case
through supply chamber 31.
[0038] It will be noted from FIG. 1 that the level of molten
reactant metal 16 in feed chamber 11 may be higher than in heating
chamber 15 and output chamber 14. In this arrangement the molten
reactant metal 16 provides a hydrostatic head which helps cause the
molten metal to flow from feed chamber 11 into treatment chamber 12
and then into output chamber 14. However, the desired flow rates
and vortex or swirling flow may be produced without the higher
molten reactant metal level in feed chamber 11. Also, it will be
appreciated that the desired flow rates of molten reactant metal
into treatment chamber 14 may be produced without the illustrated
molten metal pumps. As discussed above, in alternative arrangements
a portion of the molten reactant metal from heating chamber 15 may
be lifted in a suitable vessel and dumped into feed chamber 11 (or
into supply chamber 31) in order to produce the desired flow of
reactant metal 16 through the feed chamber and into treatment
chamber 12. Alternatively, molten reactant metal 16 may be
collected in supply chamber 31 and released abruptly to flush feed
material from feed chamber 11 into treatment chamber 12.
[0039] FIG. 3 shows an alternate vortex inducing arrangement
according to the invention. This alternative form of the invention
includes the same preferably bowl-shaped feed chamber 11, treatment
chamber 12, and heating chamber 15 included in the embodiment shown
in FIGS. 1 and 2. FIG. 3 is broken to omit other portions of the
reactor that are identical to those set out in FIGS. 1 and 2, and
do not involve the alternate vortex inducing arrangement. In the
form of the invention shown in FIG. 3, an impeller 80 is included
to help induce the desired swirling or vortex flow of molten
reactant metal in feed chamber 11. Impeller 80 may comprise any
suitable impeller device suitable for use in a molten reactant
metal. U.S. Pat. No. 4,930,986 shows a suitable impeller, and is
incorporated herein by this reference. The type of impeller shown
in this patent also forces feed material and molten reactant metal
downwardly in feed chamber 11 toward the outlet to treatment
chamber 12. Impeller 80 is driven by drive shaft 81 about a
vertical axis V aligned generally in the center of feed chamber 11.
A suitable motor and drive device 82 rotates drive shaft 81. Drive
shaft 81 preferably extends though a protective conduit 84. Conduit
84 helps protect drive shaft 81 from feed material entering the
reactor through feed arrangement 85.
[0040] Because the center portion of feed chamber 11 is occupied by
the impeller 80 and supporting structure, feed arrangement 85
differs from feed arrangement 24 shown in FIG. 1. Feed arrangement
85 includes an elongated feed chute 86 that extends at an acute
angle with respect to axis V. Feed chute 86 includes upper and
lower dump gates 87 and 88 respectively to define a purge chamber
89 similar to purge chamber 36 shown in FIG. 1. The dump gates
purge line 90 and purge chamber all operate similarly to the
corresponding elements shown in FIG. 1 and thus will not be
described further here.
[0041] An outlet end 91 of feed chute 86 represents a feed material
inlet to feed chamber 11 and terminates in a sealing or confinement
conduit 94 similar to the sealing conduit 42 shown in FIG. 1 and
functions similarly to help confine feed material just to the
volume of molten reactant metal 16 immediately above the feed
chamber outlet 28.
[0042] The flow rate of molten reactant metal 16 into and out of
feed chamber 11 may be the same as in the embodiment described with
reference to FIGS. 1 and 2. Thus, the flow of molten metal 16
through inlet 29 and the bowl shape of feed chamber 11 may be
sufficient to induce some swirling flow in the feed chamber around
axis V. Impeller 80 enhances the swirling flow and further helps to
submerge and entrain feed material in the molten reactant metal 16
so that the feed material may be quickly carried in the flow of
molten metal into treatment chamber 12.
[0043] FIG. 4 shows yet another alternate feed arrangement for a
reactor within the scope of the present invention. This alternative
feed arrangement includes a treatment chamber 12 and heating
chamber 15 similar to those described in FIG. 1. The output chamber
14 and related components are also similar to those shown in FIG. 1
and are therefore omitted from FIG. 4.
[0044] The alternative feed arrangement shown in FIG. 4 includes a
feed chamber 95 that is just large enough in diameter to
accommodate an impeller 96 similar to impeller 80 described above
with reference to FIG. 3. Impeller 96 is driven on a shaft 97 by
motor 98 and the shaft is protected by housing 99. Molten reactant
metal 16 enters feed chamber 95 through inlet 101 which preferably
resides near the level of molten reactant metal maintained in the
feed chamber. Impeller 96 is positioned so that it traverses the
level of the molten reactant metal 16 in feed chamber 95, and
preferably comprises an impeller such as that described in U.S.
Pat. No. 4,930,986 to force materials downwardly along axis V in
the feed chamber. The illustrated preferred positioning of impeller
96 also allows the impeller to contact and quickly submerge feed
materials into the molten reactant metal 16 in feed chamber 95. In
other arrangements within the scope of the accompanying claims, the
impeller may be located below the level of molten reactant metal in
feed chamber 95. In other arrangements within the scope of the
invention or set out in the accompanying claim, the impeller may be
below the level of molten reactant metal.
[0045] Feed materials enter feed chamber 95 through feed material
conduit 104. A suitable feed material pump 105 pumps or forces feed
material from a feed material supply vessel 106 through conduit 104
and into feed chamber 95. Feed material pump 105 may comprise a
diaphragm pump or an auger type pump for example. This feed
material arrangement shown in FIG. 4 is particularly suited for
feed materials in the form of loose particles such as loose soils
or feed materials in the form of a slurry.
[0046] The pumping arrangement for the feed material obviates the
need for the purge chamber and dump gate arrangement shown in FIGS.
1 and 3. The positive pressure provided by pump 105 prevents gasses
from exiting feed chamber 95 through feed material conduit 104. A
pressure relief line 107 with suitable valving may be provided in
the top of feed chamber 95 to periodically remove reaction product
gasses or other gasses that might collect in the feed chamber.
Depending upon the nature of these gasses, the gasses removed
through line 107 may or may not be subjected to treatment before
release to the atmosphere. In some cases the gasses may simply be
directed through particulate control equipment associated with the
reactor's reaction product removal equipment shown in FIG. 1.
[0047] The above described preferred embodiments are intended to
illustrate the principles of the invention, but not to limit the
scope of the invention. Various other embodiments and modifications
to these preferred embodiments may be made by those skilled in the
art without departing from the scope of the following claims. For
example, the feed pump and feed conduit 104 arrangement shown in
FIG. 4 may be replaced by the feed chute and dump gate arrangement
shown in FIG. 3, and the feed chambers 11 shown in FIGS. 1 and 3
may include a relief line similar to line 107 shown in FIG. 4.
Also, those skilled in the art will appreciate that many technical
details have been omitted from the diagrammatic representations
shown in FIGS. 1 and 2 in order to avoid obscuring the invention in
unnecessary detail. These details such as valves and control
systems will be apparent to those of ordinary skill in the art from
the above description of molten metal reactor 10.
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