U.S. patent application number 13/648219 was filed with the patent office on 2013-02-07 for compositions, methods and devices for control and clean-up of hazardous spills.
This patent application is currently assigned to HONEYWELL INTERNATIONAL, INC.. The applicant listed for this patent is HONEYWELL INTERNATIONAL, INC.. Invention is credited to Ian Shankland, Rajiv R. Singh.
Application Number | 20130034474 13/648219 |
Document ID | / |
Family ID | 40119412 |
Filed Date | 2013-02-07 |
United States Patent
Application |
20130034474 |
Kind Code |
A1 |
Singh; Rajiv R. ; et
al. |
February 7, 2013 |
COMPOSITIONS, METHODS AND DEVICES FOR CONTROL AND CLEAN-UP OF
HAZARDOUS SPILLS
Abstract
Disclosed are methods for treating hazardous materials, such as
those which result from an unwanted spill or leak, which comprise
one or more of the steps or effects of: neutralizing the dispersed
material; solidifying the dispersed material; immobilizing the
material; and/or reducing the evolution of harmful or unwanted
gaseous forms from the spillage, preferably using a binding agent
which comprises a polyacrylate-polyacrylamide cross-linked
copolymer.
Inventors: |
Singh; Rajiv R.; (Getzville,
NY) ; Shankland; Ian; (Randolph, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONEYWELL INTERNATIONAL, INC.; |
Morristown |
NJ |
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL,
INC.
Morristown
NJ
|
Family ID: |
40119412 |
Appl. No.: |
13/648219 |
Filed: |
October 9, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12132764 |
Jun 4, 2008 |
8309034 |
|
|
13648219 |
|
|
|
|
60943044 |
Jun 9, 2007 |
|
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Current U.S.
Class: |
422/291 ;
252/189 |
Current CPC
Class: |
C09K 3/32 20130101; B01J
19/06 20130101; B01J 20/26 20130101; B01J 19/00 20130101; B01J
20/264 20130101; B01J 20/267 20130101; B01J 2220/445 20130101; B01J
20/261 20130101 |
Class at
Publication: |
422/291 ;
252/189 |
International
Class: |
C09K 3/32 20060101
C09K003/32; B01J 19/00 20060101 B01J019/00 |
Claims
1. A composition for treating hazardous material containing acidic
material comprising a binding agent and a carrying agent for
delivering said binding agent to the hazardous material, said
binding agent comprising at least one cross-linked copolymer
comprising acrylamide units and acrylate units.
2. The composition of claim 1 wherein said composition further
comprises a water soluble polymer selected from the group
consisting of cellulose ethers, modified starches, starch
derivatives, natural gum derivatives, polyacrylic acid salts,
ethylene oxide polymer, methacrylic acid polymer, polyethyleneimine
polymer, polyvinyl pyrrolidone polymer and mixtures thereof.
3. A system capable of treating acid-containing hazardous material,
said system comprising: binding agent; carrying agent for carrying
said binding agent to the area of the hazardous material, said
carrying agent comprising a fabric carrying or made from said
binding agent; a discharge chute capable of holding said fabric;
and means for propelling said fabric to the site of the hazardous
material from a safe distance therefrom such that the fabric comes
in contact with at least a portion of said hazardous material and
wherein said binding agent reduces the risk from said hazardous
material.
4. The system of claim 3 wherein said discharge chute is connected
to a gun which carries said propelling means.
5. The system of claim 3 wherein said system further comprises at
least a first tank containing at least a portion of said binding
agent and means to propelling binding agent from said tank to the
site of the hazardous material from a safe distance therefrom.
6. A system capable of treating acid-containing hazardous material,
said system comprising binding agent and means for delivering said
binding agent to the area of the hazardous material, said binding
agent comprising a cross-linked copolymer comprising acrylamide
units and acrylate units, wherein said system further comprises at
least a first tank containing at least a portion of said binding
agent and means to propelling binding agent from said tank to the
site of the hazardous material from a safe distance therefrom.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of, and thus claims
priority under 35 U.S.C. .sctn.120 to, U.S. patent application Ser.
No. 12/132,764, filed on Jun. 4, 2008, which claims priority under
35 U.S.C. .sctn.119(e) to U.S. Provisional Application No.
60/943,044, filed on Jun. 9, 2007, and to U.S. Provisional
Application No. 60/943,447, filed on Jun. 12, 2007. U.S. patent
application Ser. No. 12/132,764 and U.S. Provisional Application
Nos. 60/943,044 and 60/943,447 are incorporated herein by
reference.
BACKGROUND
[0002] 1. Field of Invention:
[0003] The present invention relates to compositions, methods, and
devices for containment, mitigation, neutralization and/or clean-up
of unwanted dispersals of hazardous material, particularly spills
of acidic materials such as hydrogen fluoride-containing
compositions.
[0004] 2. Description of Related Art:
[0005] Hydrogen fluoride is a well known compound that is used in
industry in a variety of processes including in alkylation
reactions as a catalyst, in fluorination reactions as a
fluorinating agent, in the manufacture of fluorides, in the
separation of uranium isotopes, and in the production of fluorine
containing plastics. It is well known that hydrogen fluoride is a
volatile, extremely hazardous substance. Moreover, the high vapor
pressure of hydrogen fluoride renders it readily aerosolizable.
[0006] Various compositions and methods have been known to be
useful for the clean-up of hazardous materials, particularly
acid-containing materials, and more particularly materials which
contain hydrogen fluoride. However, many of these compositions and
methods have certain disadvantages.
[0007] U.S. Pat. No. 4,383,868--Braley relates to a method of
treatment of spillages of hazardous chemicals in a liquid form, and
in particular to a method of treatment of such spillages for
controlling and clean-up of a spill of hydrofluoric acid. The
method disclosed in this patent involves the application to a spill
of a solid particulate mixture containing both polyacrylamide and a
polymer or copolymer of an alkyl(alk)acrylate. The material is said
to immobilize the spillage and reduce the evolution of fumes from
the spillage, and is said to be more effective in the treatment of
spillages of many hazardous liquid chemicals than is either the
polyacrylamide or the polyalkyl(alk)acrylate when used alone. The
U.S. Pat. No. 4,383,868 patent indicates that the polymer or
copolymer of the alkyl(alk)acrylate may be a polymer derived from
one or more alkyl(alk)acrylates, e.g. methyl acrylate, ethyl
acrylate, methyl methacrylate, butyl methacrylate or ethyl
methacrylate, or it may be a copolymer of a substantial proportion
of units derived from one or more alkyl(alk)acrylates, e.g. at
least 80 mole %, and units derived from one or more ethylenically
unsaturated monomers copolymerisable therewith. The patent teaches
that the amount of polymer or copolymer of the alkyl(alk)acrylate
should not be present in the composition in an amount that is
greater than 80% by weight of the particulate mixture used in the
treatment of hazardous chemicals.
[0008] U.S. Pat. No. 4,865,761--Mandel et al. relates to methods
and compositions for neutralizing and solidifying hazardous organic
spills. The disclosed composition, in addition to optional
ingredients, contains about 5 to 30% of absorptive clay and about
10 to 50% portland cement. Such compositions and methods have the
disadvantages of being relatively heavy to transport to the site of
the hazardous spill as well as the difficulty associated with
cleanup and/or recovery of the hazardous material once it is
neutralized and absorbed into the disclosed composition.
[0009] While prior methods may have achieved some degree of
success, applicants believe that several disadvantages exist and
that there is a need for better methods, devices and compositions.
For example, applicants believe that a need continues to exist for
clean-up and treatment materials and methods in which the treating
materials have advantageous properties, such as higher capacity to
absorb, retain, immobilize, etc. the hazardous material, such as
HF, per unit mass of treatment material. The present invention
satisfies these needs among others.
SUMMARY OF THE INVENTION
[0010] This invention is directed to novel compositions and
methods, and to devices which use such compositions and methods, to
treat hazardous spill conditions. As used herein, the term "treat"
means to lessen or reduce the negative or harmful effects on the
environment and/or living things of a dispersal of chemicals,
usually in the form of an unintended spill of such materials. In
certain preferred embodiments, the hazardous material comprises an
acid-containing material. The treatment methods of the present
invention in preferred embodiments may comprise one or more of the
steps or effects of: neutralizing the dispersed material;
solidifying the dispersed material; immobilizing the material;
and/or reducing the evolution of harmful or unwanted gaseous forms
from the spillage. It should be understood that each of the above
steps/effects may act on only a portion of the spilled material,
but in preferred embodiments the methods and compositions are
delivered and provided in a manner such that one or more of the
desired effects is achieved on a substantial portion, and even more
preferably substantially all of the dispersed hazardous
material.
[0011] In preferred embodiments, the compositions and methods of
this invention are applied from a safe distance, thus allowing
substantially all of the spill to be reacted, neutralized,
immobilized and/or devolitized (at least partially but
preferentially substantially entirely) with minimal harm to safety
workers and others in the area of the spill.
[0012] The present inventors have found that the present methods
can be carried out in preferred embodiments by contacting, and
preferably substantially covering, at least a portion of the
hazardous material which has been spilled, leaked or otherwise the
subject of an unwanted dispersal, with one or more binding agents.
As a result of the preferred contacting step of the present
invention, a mass is created which comprises the hazardous material
and the binding agent in a form that is substantially less
hazardous than the material without the binding agent. For the
purposes of convenience, but not necessarily by way of limitation,
the mass comprising the binding agent and the hazardous material is
sometimes referred to herein as the "treated mass." The preferred
binding agents can be advantageously used to produce a treated mass
having one or more of the advantageous characteristics, properties,
and/or effects described hereinabove. Examples of binding agents
believed to be generally adaptable for use in connection with the
present invention are described in the following pending
applications, each of which is assigned to the assignee of the
present application: Application No. 60/943026 (Attorney Docket No.
H0014675 (33631); and Application No. 60/943033 (Attorney Docket
No. H0012283 (33342)).
[0013] In certain preferred embodiments, the binding agent
comprises, and preferably consists essentially of, one or more
polyacrylate-polyacrylamide cross-linked copolymers in accordance
with the teachings contained herein. The preferred cross-linked
copolymers have a substantial ability, especially when used in
accordance with the preferred method steps described herein, to
achieve and provide a treated mass having the desirable properties,
characteristics, effects and/or modes of operation described
herein. For example, the preferred polyacrylate-polyacrylamide
cross-linked copolymers of the present invention exhibit a much
higher capacity for retaining acidic materials, such as hydrogen
fluoride (HF), than many of the other materials which have been
known for use in such applications. The surprisingly high capacity
of these preferred binding agents is particularly advantageous in
accordance with the present methods, compositions and devices. For
example, the large capacity of the present materials means that the
relative proportion of hazardous material (such as HF) to binding
agent (e.g., copolymer) in the treated mass is high, which means
that the amount of binding material (and potentially the cost
thereof) that needs to be transported to the spill site is reduced.
This in turn permits the site, in preferred embodiments, to be
treated more quickly and more effectively than prior materials,
resulting potentially in an important saving of health and the
environment.
[0014] In addition, it has been found by the present inventors that
intimate mixtures of polyacrylate-polyacrylamide cross-linked
copolymers and acidic materials, particularly hydrogen fluoride,
which preferably form as a result of the present methods and the
use of the present devices in certain embodiments as disclosed
herein, result in a treated mass in which the volatility of the
hazardous material (such as hydrogen fluoride) is diminished. This
treated mass is also preferably more viscous and has a greater
surface tension as compared to the acidic material generally, thus
hindering formation of an acidic material in a gaseous or fluid
state, including an aerosol cloud. Therefore, the compositions,
methods and devices of the present invention permit a dramatic
reduction in the immediate harm that such a spill would otherwise
create relative to many of the previously used methods. Moreover,
the present invention in certain aspects can make the spill zone
easier to clean up and/or remediate.
[0015] Accordingly, the present invention in one aspect provides a
treatment material comprising a binding agent, which preferably
comprises a cross-linked copolymer comprising acrylamide and
acrylate, preferably in the form of a solid or a gel, and an agent
to assist carrying the copolymer to the material causing the
hazard. In certain preferred embodiments, the carrying agent
comprises a propulsion agent, which is preferably intimately
engaged with the copolymer and provides motive force to the binding
agent to carry it to the hazardous material. Preferably in such
embodiments the carrying agent is a gas that is relatively inert,
stable, readily removed or dispersed, and which is not itself
inherently harmful to the environment or to health. Examples of
such carrying agents include pressurized nitrogen.
[0016] In certain highly preferred embodiments of the invention,
the present treatment material comprises a cross-linked copolymer
comprising acrylamide cross-linked with an acrylic acid salt,
wherein such treatment material is preferably in the form of a
solid or a gel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic view, in axial longitudinal section,
of one embodiment of a portable treatment device according to one
embodiment of the invention.
[0018] FIG. 2 is a view of a detail of FIG. 1 on an enlarged
scale.
[0019] FIG. 3 is a perspective view of another embodiment of a
portable treatment device of the present invention.
[0020] FIG. 4 is an environmental view of the treatment device
after deployment at hazard spill.
[0021] FIG. 5 is a graphical representation of vapor pressure as a
function of temperature and HF-Gel composition.
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
The Methods and Devices
[0022] Among the method aspects of the present invention, one
embodiment includes the steps of providing a binding agent and
applying the binding agent to at least a portion of the spill or
otherwise unwanted dispersal of hazardous material. The binder
providing step in certain embodiments comprises providing a source
of the binding agent in its preferred form for use in treatment. In
other embodiments, the binding agent may be provided in preferred
forms as part of applying step. For example, in certain
embodiments, the binding agent may be provided in the form of a
solid block or sheet of binder which is not well adapted to direct
application to the hazardous material. In such cases, the step of
applying the binder may include the step of converting the block or
solid sheet into a fine particulate form of the binder. This might
occur in certain preferred embodiments, for example, in which an
explosive or other high energy force is used to propel the binder
material also first comminutes the block, film or sheet such that
the binding agent is delivered to the site in the form of fine
particles, powder and/or aerosol. Such embodiments may have
advantages in certain applications relating to the portability of
the material to the hazard site.
[0023] In preferred embodiments, the applying step results in
contact between the binding agent and the hazardous material that
is effective to form a treated mass that is less hazardous than the
material prior to the contacting step. Although it is contemplated
that the preferred contacting step forms a treated mass over a wide
range of time periods, it is preferred that the time from initial
contact to the point where such less hazardous treated mass is
formed is not in excess of several hours, and more preferably is
less than about 3 hours, and even more preferably less than about 1
hour. This time period will of course be a function of many
parameters associated with each application, and all such time
periods are within the scope of the present invention.
[0024] In certain preferred embodiments, the applying step
comprises providing a carrying agent, such as a pressurized gas,
and engaging the binding agent with the carrying agent such that
the binding agent is propelled, for example by impulse discharge
associated with a pressure differential, into contact with the
hazardous material. The particular configuration of such devices
may vary widely within the scope of the present invention, and all
such configurations are within the scope hereof. It is
contemplated, for example, that devices which have heretofore been
used to effect sand blasting or other treatment by carrying an
abrasive or other particulate material to a target site may be
readily adapted for use in connection with the present invention.
It is preferred, however, that the discharge velocity and/or
pressure from such devices is controlled, or the impact of the
discharge stream is otherwise limited, to ensure or at least
minimize the extent to which the hazardous material is dispersed
over a substantially greater area upon exposure to the delivery of
the binding agent. The use of a net as described in detail
hereinafter may serve the purpose, in addition to other purposes,
of limiting the impact of the discharge stream to ensure or at
least minimize the extent to which the hazardous material is
dispersed over a substantially greater area.
[0025] In other embodiments, the applying step comprises providing
a carrying agent that possesses a motive force produced by a
chemical reaction, such as results, for example, from the reaction
of an oxidizing agent and a solid fuel subsequent to ignition
thereof. In many embodiments, such a carrying agent produced by
such a reaction is in the form of an aerosol which carries the
binding agent to the hazard site. Such an aerosol is sometimes
referred to herein as a "pyrotechnically generated aerosol." The
binding agent of the present invention can be incorporated in a
canister or module of known type to effect delivery of the binding
agent to the hazardous material. Such embodiments are particularly
effective under circumstances in which the hazardous material is
not exposed to changing environmental conditions, such as large
changes in airflow or other weather changes.
[0026] In other embodiments, the applying step comprises providing
a carrying agent in the form of a fabric or other matrix of fibers
which carries or otherwise incorporates or is capable of carrying
the binding agent and then delivering the fabric or other matrix of
fibers to the hazardous material. For example, in such embodiments,
the copolymer may be embedded in, coated on, and/or integrated in
the form of fibers into a fabric, such as a web or mesh, which can
be readily delivered to the hazardous material, preferably in
certain embodiments by forming a blanket or curtain which can be
deployed so as to cover or surround at least a portion of hazardous
spill. In certain embodiments, such a deployment may involve
forming such a mesh, web, curtain or similar article and propelling
the material containing or carrying the copolymer so as to cover at
least a portion of the area of the spill.
[0027] Many devices known to those in the art may be used to
deliver the binding agent to the hazardous material, and all such
devices are within the scope of the present invention. In certain
preferred embodiments, the delivery device or system of the present
invention includes at least one container and/or conduit for
holding the carrying agent and/or the binding agent, and means for
discharging the carrying agent and the binding agent from a
location safely separated from the hazardous material so as to
deliver the binding agent into contact with at least a portion of
the hazardous material. In one embodiment, the preferred device
comprises a fire extinguisher-type device in which at least the
carrying agent is an inert gas stored or otherwise provided under
pressure. In other cases, the carrying agent is generated in or by
the device as a result of an explosive discharge.
[0028] One embodiment of a device which utilizes an explosive
discharge which may be adapted for use in connection with the
present invention in view of the teachings contained herein is
illustrated in FIGS. 1 and 2. With reference initially to FIG. 1, a
portable binding agent delivery device, generally indicated 1,
comprises a handle 2 and an elongate tubular casing 3, having a
distal end 3a and a proximal end 3b which is fixed to the handle 2.
A chamber 4 is defined in the casing 3 for housing a charge 5 of a
solid substance which can be transformed, at a predetermined
temperature, into a carrying agent of the present invention,
preferably in the form of an aerosol. In one embodiment, the charge
5 includes not only reactive components but also incorporates a
binding agent of the present invention, preferably in small
particulate form, distributed therein. The chemical and physical
characteristics of the reactive components of the mass 5 are not
relevant per se for the purposes of an understanding of the
invention and will therefore not be described in detail herein,
except to note that they are preferably selected such that the
reaction conditions do not cause a deleterious change in the
binding agent, that is, a change that would prevent the functioning
of the binding agent. By way of one example that may be applicable
for certain binding agents, the reactive components comprise a
compacted mixture comprising potassium nitrate, a resin, and an
organic oxidizing agent.
[0029] A sleeve-like portion 8 of a plug, generally indicated 9, is
inserted in the opening 7.
[0030] The plug 9, which is preferably made of plastics material,
is held on the distal end of the tubular casing 3 by means of a
peripheral rim 10 and by radial interference between the delivery
opening 7 and the central sleeve-like portion 8. In this portion, a
starting capsule, generally indicated 11, is held in an outer or
front position, and an associated delay fuse 12 is held in a
position immediately further in or to the rear, interposed between
the capsule 11 and the charge 5. The starting capsule 11 includes a
small inflammable charge 13 arranged closely in contact with the
end portion 16a of a manually-operable activation element 16, for
example, a metal wire, a cord, or the like, which the user can pull
by gripping a gripping ring 15. The inflammable charge 13 is
contained in a thin inverted cup-shaped container 17, the base of
which has a central hole for the insertion of the cord 14. The plug
9 has a transverse wall 18 with a hole 19 aligned with the hole in
the container 17. A protective cover 20 closes the distal end of
the fire-extinguisher to protect the starting capsule 11 and its
activation element 16. In preferred operation, the user opens the
cover 20, grips the gripping ring 15 and pulls the cord 14
energetically in the direction indicated by the arrow A. The
friction or other forces exerted by the activation element against
the inflammable charge 13 brings about ignition thereof and the
production of a flare which lights the fuse 12. The fuse, which
preferably burns for a few seconds, gives the user time to move his
hand away from the distal portion of the device before the carrying
agent and binding agent are discharged. When the combustion, which
is propagated along the fuse 12, reaches the reactive elements in
mass 5, it triggers the exothermic chemical reaction thereof, with
the production of an aerosol suspension of particles of extremely
small particle size. The increase in pressure which accompanies the
reaction causes the expulsion of the plug 9. The aerosol fluid
produced by the combustion of the charge is discharged
energetically from the opening 7 and can be directed towards the
hazardous material from a safe distance.
[0031] In an alternative form of the device, the binding agent may
be provided as a separate mass positioned to be jettisoned from the
end of an elongated version of tubular casing 3. In such
embodiments, the cord 14 may be passed through a small, sealed
opening in a side wall of the casing, with binding agent located in
the tube on the distal side of the charge 13. In such embodiments,
the binding agent may be provided in particulate form, or the
binding agent may be in a form that is frangible upon operation of
the device so as to produce the desired size of binding particles.
Alternatively, the device of FIGS. 1 and 2 may be modified to carry
a fabric of the present invention packed in a distal portion of the
casing so as to be ejected by the reactive forces in a manner
designed to cover the desired area in which the hazardous material
is located. Further, it should be appreciated that any combination
of any two or more of these options may be incorporated into a
device so, for example, both a binding agent impregnated net and an
aerosol of binding agent particles are ejected upon operation of
the device.
[0032] Another embodiment which would permit the multiple modes of
operation is disclosed in FIGS. 3 and 4. Referring now to the
drawings, it is seen that the device preferably incorporates a
treatment net of the present invention, generally denoted by
reference numeral 10. In the preferred embodiment illustrated, the
net 12 is generally round in shape and has a central point 14 and
an outer periphery 16. It will be appreciated, however, that other
shapes are adaptable for use in accordance with the present
invention. The net 12 is manufactured from a fabric or mesh which
incorporates a binding agent of the present invention. For
embodiments in which the hazardous material also presents a danger
of explosion, the net may preferably be formed of an explosion
containment material, which material has a high tensile strength,
such as aramid yarn (sold under the trademark KEVLAR and
manufactured by the E.I. Du Pont de Nemours and Company), which is
an organic yarn within the family of aromatic polyamides.
[0033] Although in certain embodiments the net 12 may be
un-tethered to the device, in certain preferred embodiments the net
is connected via a tether 40 (see FIG. 4) to the device 10. In the
illustrated embodiment, the tether 40 is a tubular tether for
purposes of delivering a separate flow of binding agent to the
hazardous site as described herein below, although it will be
appreciated that the tether need not perform this function in all
embodiments. Likewise, it will be appreciated that the net need not
be a carrying agent for binder in those embodiments in which the
tether 40 is a tubular tether for delivering binding agent to the
hazardous material. Nevertheless, it is generally preferred that
the device incorporate both mechanisms for delivering binding
agent.
[0034] In preferred embodiments, a nozzle 18 is located on the net
12 and may be located at the central point 14. Preferably a series
of weights 20 are located on the net, preferably about the outer
periphery 16 of the net. The device/system of this embodiment of
the invention includes a gun 24 having a cone loader 26,
appropriate hand grips 28, a butt stock 30 (if desired) and a
trigger 32. Of course, the shape of the loader may be readily
modified according to the shape of the net being used. In preferred
embodiments, the gun is configured to have the loader readily
replaceable so that the shape and size of the net may be selected
upon arrival at the site to suit the circumstances of each hazard
condition. A bayonet type arrangement may be used to make the
loader readily replicable to suit size and shape needs. Screw-type
mounting of the loader is also possible.
[0035] The gun may be pneumatically fired wherein a source of high
pressure gas (not illustrated) provides the pneumatic force to fire
the gun 24. This high pressure gas source may be either an external
or internal canister or may be a small cartridge that is fed into
the gun through the gun's chamber 34. Alternately, the gun 24 may
be fired by a firing cartridge such as a standard firing blank.
[0036] A first tank 36 is provided and holds a carrying agent
and/or binding agent. A second tank is also provided in certain
embodiments for holding carrying agent and/or binder, or possibly
other materials which may be desirable to deliver also the site of
the hazardous material. The first tank 36 and the second tank 38
are fluid flow connected with the nozzle 18 on the net 12 via a
conduit 40 which passes through the gun 24 so that the trigger 32
on the gun can control discharge of the contents of the two tanks
36 and 38. In preferred embodiments the two tanks 36 and 38 pass
through a manifold 42 prior to entering the conduit 40. A section
of the conduit 40 (the section that is disposed between the gun 24
and the nozzle 18) may be coiled for compactness of design.
Carrying straps 44 may be provided for ease of carrying of the two
tanks 36 and 38.
[0037] Preferably the manifold 42 is selectable so as to allow the
carrying agent to be held in one tank and the binder to be held in
another tank such that mixing of the two can occur in the manifold
or in appropriately designed chambers of the gun. Of course, it is
possible that in certain embodiments the carrying agent and binder
are premixed and held together in one or both of the tanks In other
embodiments, the tanks may hold only binding agent and the carrying
agent is supplied via nozzles 28.
[0038] In operation, the net 12 is folded appropriately and placed
into the cone loader 26 of the gun 24 and the gun 24 is
appropriately primed (either a firing cartridge is inserted into
the firing chamber 32 or a supply of pressurized gas is provided
for the gun). Once the user identifies an appropriate target for
treatment, such as a spill of HF, the user squeezes the trigger 32
in order to fire the gun 24 which propels the net 12 at the target
in order to drape the net 12 over the hazardous material, or at
least a portion thereof. The weights 20 along the outer periphery
of the net 12 help the net land appropriate about the target in
order to effectively cover the target area. Continued squeezing of
the trigger 32 causes operation of the carrying agent such that
binding agent is discharged through the nozzle 18 onto the target
being covered by the net 12. Of course this sequence of operation
may be altered within the scope of the present invention.
[0039] In certain embodiments, the deployment means propels the
binding agent with a force adequate to substantially disperse the
binding agent throughout the hazardous liquid. That is, the binding
agent is mixed with the hazardous liquid so as to rapidly and
substantially form a less hazardous composition. In other
embodiments, the deployment means propels the binding agent onto
the surface of the hazardous liquid where it forms a protective
layer over the liquid. In still other embodiments, the deployment
means propels the binding agent onto the surface or into one or
more discrete portions of the hazardous liquid from which it is
subsequently mixed with the hazardous liquid. It will be
appreciated that a device or method may comprise any combination of
two or more of these and other deployment means.
[0040] In certain preferred embodiments of the invention, provided
is a system for suppressing the spread of an acid-containing
hazardous material, said system comprising: a container, preferably
a portable container, having an interior portion and an exterior
side, said interior portion being adapted to receive a propellant;
a propellant in fluid communication with said interior portion; a
nozzle, preferably a pivotal nozzle, disposed on said exterior
portion and in fluid communication with said interior portion; and
a binding agent disposed within said interior portion or said
nozzle. Preferably, the binding agent in such embodiments comprises
at least one cross-linked copolymer comprising acrylamide units and
acrylate units in solid form, preferably pellets, powder, granules,
fibers, or some combination thereof. Preferably, the propellant is
disposed within the container and is a combustible fuel, a
pressurized gas, or a compressed liquid, such as for example,
nitrous oxide, carbon dioxide, air, noble gas, hydrofluoroalkane,
hydrofluoroolefin, and combinations thereof.
[0041] The Compositions
[0042] In preferred embodiments, the hazardous material is
contacted by a composition comprising a binding agent, such as an
absorbent polymer or complexing agent, to form a treated material
comprising at least a portion of the hazardous material, wherein
the treated material is a solid, semisolid, or viscous liquid,
and/or has a vapor pressure that is at or below ambient pressure,
and/or has a high surface tension. In preferred embodiments, the
acidic material, preferably HF, being treated is substantially
unchanged in its chemical make-up from its untreated state and,
thus, may be readily and quantitatively recovered from the treated
material.
[0043] As used herein, the term "restraining" means to hold back or
keep in check.
[0044] Examples of restraining include, but are not limited to,
immobilization and suppression of a propensity to volatilize and/or
aerosolize.
[0045] As used herein, the term "immobilizing" means to impede
movement.
[0046] As used herein, the term "hazardous" means a property or
condition that imperils or otherwise adversely effects the safety
or stability of a person, plant, animal, or the environment, or is
a nuisance if unrestrained. Examples of hazardous materials
include, but are not limited to, those that are flammable,
corrosive, explosive, carcinogenic, toxic, mutagenic, odoriferous,
radioactive, volatile, or otherwise chemically unstable.
[0047] As used herein, the term "binding agent" means a material
having the capacity to exert or create a strong chemical or
physiochemical attraction between two substances. Examples of
strong chemical and physiochemical attractions include ionic
bonding, nonionic bonding, electrophilicity, electrophobicity, and
the like. Examples of binding agents include, but are not limited
to, absorbent polymers, such as hydrogels, and complexing agents,
such as ionic liquids.
[0048] Preferably, the binding agent is in a form that is easily
and rapidly deployable into a liquid or onto the liquid's surface.
Examples of easily and rapidly deployable forms include liquid and
solids such as powder, granules, pellets, fibers, or combinations
thereof.
[0049] In certain preferred embodiments, the composition binds the
hazardous material in such a way as to readily release the
hazardous material under certain conditions, such as changing the
temperature and/or pressure of the composition. In such
embodiments, the hazardous material may be recovered after it has
been re-secured.
[0050] In certain embodiments, the carrying agent may comprise a
compressed gas, such as air, nitrogen, carbon dioxide, or a noble
gas instead of, or in addition to, an oxidizable fuel. For such
embodiments, the compressed gas is rapidly released and propels the
binding agent.
[0051] The choice of binding agent is primarily determined based
upon the hazardous material held in the receptacle. Examples of
hazardous materials that may be practiced with the present
invention include, but are not limited to, nitric acid,
concentrated sulphuric acid, concentrated hydrochloric acid,
aqueous sodium cyanide, anhydrous sodium cyanide, aqueous hydrogen
cyanide, anhydrous hydrogen cyanide, bromine, bromine trifluoride,
ammonia, trifluorophosphine, titanium tetrachloride, oleum,
chlorosulphonic acid, chlorine, fluorine, aqueous hydrogen
fluoride, anhydrous hydrogen fluoride, phosgene, petroleum, and
derivatives thereof. As used herein, the term "derivative" means a
compound or chemical structure having the same fundamental
structure, underlying chemical basis, or chemical properties as the
relevant related compound. Such derivatives are not limited to, but
may include, a compound or chemical structure produced or obtained
from the relevant related compound.
[0052] In certain preferred embodiments, the binding agent is an
absorbent material.
[0053] Particularly preferred absorbent materials are absorbent
polymers. Examples of absorbent polymers include, but are not
limited to, polyacrylamide, polyalkylacrylamide, polyacrylate,
polyalkylacrylate, polyacrylic acid salts, cross-linked
polyacrylamide-polyacrylate copolymer, cellulose ethers, modified
starches, starch derivatives, natural gum derivatives, ethylene
oxide polymer, polyethyleneimine polymer, polyvinyl pyrrolidone
polymer, and mixtures or copolymers thereof. Such binders are
described, for example, in U.S. Pat. No. 4,383,868 and U.S.Pat. No.
6,177,058, each of which are incorporated herein by reference.
[0054] These absorbent polymers are particularly preferred for
binding nitric acid, concentrated sulphuric acid, concentrated
hydrochloric acid solution, aqueous sodium cyanide solution,
bromine, titanium tetrachloride, oleum, chlorosulphonic acid and
anhydrous hydrogen fluoride.
[0055] For binding anhydrous and aqueous hydrogen fluoride,
polyacrylate-polyacrylamide cross-linked copolymers, particularly
those derived from a polyacrylic acid salts, and mixtures of
cross-linked polyacrylamide-polyacrylate copolymer and at least one
of polyacrylamide, polyalkylacrylamide, polyacrylate,
polyalkylacrylate, and polyacrylic acid salts.
[0056] In certain embodiments, the binding agent is a complexing
agent. Preferred complexing agents include, but are not limited to,
organic salts, particularly organic salts that form ionic liquids.
Examples of preferred organic salts include, but are not limited
to, salt comprising a cation selected from the group consisting
tetraalkylphosphonium, tetraalkylammonium, pyridinium,
N-alkylpyridinium, N,N'-dialkylimidazolium, and imidazolium.
Particularly preferred organic salts is a substituted imidazolium
chloride, with 1-methyl-3-ethylimidazolium chloride being more
preferred. These organic salts are particularly useful for binding
chlorine. Preferred compositions of these organic salts and
chlorine have a vapor pressure that is lower than the ambient vapor
pressure.
[0057] Other binding agents that may be practiced with the
invention include polyacrylic acid which is useful for binding
aqueous and anhydrous hydrogen cyanide and ammonia; calcium
stearate which is useful for binding petroleum and petroleum-based
compounds; and azolium tetrafluoroborate, which is useful in
producing an electrolyte with bromine trifluoride and
trifluorophosphine.
[0058] In certain preferred embodiments of the invention the
binding agent comprises, and preferably comprises in major
proportion and even more preferably consists essentially of at
least one polyacrylate/polyacrylamide crossed-linked copolymer. As
used herein, the term "copolymer" means a polymer having two or
more different monomer residues that have been polymerized and
constructed as one or more chains. The arrangements of these
monomer units in the chain include those that regularly alternate
the different monomers or those that repeat monomer units in
regular or random sequences. In addition, the chain can be
straight, branched, or grafted, or can exist as a block
copolymer.
[0059] As used herein, the term "cross-linked" means the attachment
of two chains of polymer molecules by bridges composed of an
element, a functional group, a compound, or a polymer unit, which
join certain atoms of the chains by primary chemical bonds. In
certain embodiments, cross-linking occurs between two or more
polymer chains to form a copolymer structure. In certain other
embodiments, cross-linking occurs between two or more copolymer
chains that are similar in arrangement. Preferably, cross-linking
occurs between amide groups and carboxylic groups of the
copolymer.
[0060] The cross-linked copolymer of the present invention in its
dry form is preferably solid in the form of a powder, granules,
pellets, and the like. When exposed to acidic material,
particularly hydrogen fluoride, the copolymer chains expand or
unfold and uptake or absorb the acidic material to form a solid or
a semi-solid material, such a gel. Due to the copolymer's
cross-linking, the copolymer is preferably insoluble in the acidic
material, particularly hydrogen fluoride, and water.
[0061] Though not intending to be bound by a particular theory, it
is believed that hydrogen fluoride uptake by the copolymer is
facilitated by the negative carboxylic groups of the copolymer and
their hydration with hydrogen fluoride molecules. For embodiments
in which the copolymer comprises an alkali metal or ammonium ion
(e.g., copolymers form with an acrylic acid salt), it is believed
that, in the presence of hydrogen fluoride, the alkali metal or
ammonium disassociates from the carbonyl group creating two ions: a
carboxyl (COO.sup.-) and an alkali metal or ammonium ion (e.g.,
Na.sup.+). The carboxyl groups begin to repel each other because
they have the same negative charge. This repulsion unfolds or
swells the polymer chain. The swelling action also allows more
hydrogen fluoride to associate with the polymer chain and reside in
the spaces within the polymer's network.
[0062] The cross-linking between polymer chains prevents the
copolymer from dissolving in liquid hydrogen fluoride or other
liquids. When the chains become hydrated, the cross links prevent
them from moving around randomly. In general, the cross-linking
affects the copolymer's adsorption capacity, with more cross links
in a chain corresponding to a decrease in the polymer's ability to
adsorb liquids. (See, e.g., Osmosis and Super Absorbent Polymers,
U. of Illinois at Urbana-Champaign.) However, the inventors have
surprisingly found that cross-linked copolymers of the present
invention have a significantly higher capacity for liquid hydrogen
fluoride compared to the copolymer's constituent polymers
individually.
[0063] Preferred cross-linked copolymers of the present invention
are constructed of both acrylamide units and acrylate units. Within
the scope of the term "acrylamide", included is acrylamide itself
(i.e., 2-propenamide), polyacrylamides, polyalkylacrylamides (e.g.,
polymethylacrylamide), monomer residues of such acrylamides, and
derivatives thereof. As used herein, the term "derivative" means a
compound or chemical structure having the same fundamental
structure or underlying chemical basis as the relevant related
compound. Such a derivative is not limited to a compound or
chemical structure produced or obtained from the relevant related
compound. Acrylamide units that can be utilized in the present
invention include individual structural units of acrylamide,
repeating units of acrylamide, and polymer chains constructed, at
least in part, of acrylamides.
[0064] Within the scope of the term "acrylate", included is acrylic
acid (i.e., 2-propenoic acid), acrylic acid salt (e.g., sodium
acrylate, potassium acrylate, and the like), alkylacrylates (e.g.
methyl acrylate, butyl methylacrylate, and the like),
polyacrylates, polyalkylacrylates, polyacrylic salts, monomer
residues of such acrylates, and derivatives thereof. Acrylate units
that can be utilized in the present invention include individual
structural units of acrylates, repeating units of acrylates, and
polymer chains constructed, at least in part, of acrylates.
[0065] Particularly preferred acrylic acid salts include potassium
acrylate, sodium acrylate, and ammonium acrylate, with potassium
acrylate being particularly preferred.
[0066] Polyacrylate-polyacrylamide cross-linked copolymers are
commercially available from a variety of sources including Degussa
AG of Krefeld, Germany (sold under the trade name STOCKOSORB.RTM.),
Kyoritsu Yukikogyo Kenkyusho of Japan (sold under the trade name
Hymosab.RTM.200), and Aldrich of Milwaukee, Wisconsin (Cat. No.
43,277-6).
[0067] Copolymers of the present invention preferably comprise from
about 1 to about 99 weight percent, and more preferably from about
5 to about 60 weight percent, of acrylamide units based upon the
total weight of the copolymer. Copolymers of the present invention
also preferably comprise from about 1 to about 99 weight percent,
and more preferably from about 5 to about 60 weight percent, of
acrylate units based upon the total weight of the copolymer.
[0068] Generally, the cross-linked copolymers used in the invention
have molecular weights of from about 5,000 to about 10,000,000.
Preferably, cross-linked copolymers with molecular weights of from
about 5,000 to about 5,000,000 are used.
[0069] The inventors have found that the cross-linked copolymers of
the present invention have an exceptionally high capacity for
hydrogen fluoride. It is possible to measure the capacity of a
polymer for HF by mixing the polymer with an excess of HF, allowing
the mixture to sit for a period of time such that the polymer
becomes saturated, filtering off the excess HF, and weighing the
saturated polymer as well as the excess HF.
[0070] Although cross-linked copolymer capacity is important to a
practical HF-gel system, other properties should be considered as
well. Other properties of interest include exotherm upon mixing the
copolymer and HF, vapor pressure of the resulting composition,
viscosity of the composition, gelatinization time, density/volume
of the starting polymer, capacity of the composition under
pressure, ease of recovery of the HF from the composition,
reduction in HF aerosol formation by the system, and mixing or
dispersing of the polymer into HF.
[0071] It is contemplated therefore, that in addition to
polyacrylate/polyacrylamide crossed-linked copolymers, other
HF-absorbing polymers and copolymers may be practiced with the
present invention. Preferably, these other polymers and copolymers
will be mixed with the polyacrylate/polyacrylamide crossed-linked
copolymer to optimize several properties of the composition. For
example, for applications in which the time required to gel a given
quantity of HF is important, the invention involves a mixture a
copolymer having high HF capacity and another polymer or copolymer
which gels quickly. The evolution of excessive heat may accompany
the formation of the gel when HF and a copolymer or polymer are
mixed. Accordingly, certain embodiments of the invention utilize a
mixture of a high capacity cross-linked copolymer and a polymer or
copolymer with a lower capacity that exhibits a smaller
exotherm.
[0072] Examples of other polymers that may be mixed with a
polyacrylate/polyacrylamide crossed-linked copolymer include those
described in U.S.Pat. No. 6,177,058, which is incorporated herein
by reference. Preferred polymers include water soluble polymers
selected from the group consisting of cellulose ethers, modified
starches, starch derivatives, natural gum derivatives, polyacrylic
acid salts, ethylene oxide polymer, methacrylic acid polymer,
polyethyleneimine polymer, polyvinyl pyrrolidone polymer and
mixtures thereof
[0073] Without departing from the scope of the invention, it will
be recognized that other components also may be included in the
binder compositions of this invention. The specific nature of these
components will depend on the desired end use of the
compositions.
[0074] Preferably hydrogen fluoride may be recovered readily from
the treated material by exposing the treated material to conditions
effective to liberate hydrogen fluoride vapors. One means of
liberating hydrogen fluoride vapor is by heating the composition at
elevated temperatures, generally from about 0 to about 200.degree.
C., preferably from about 80 to about 150.degree. C., resulting in
the liberation of hydrogen fluoride vapor. The vapor may then be
condensed by any convenient means. Alternatively, the hydrogen
fluoride may be liberated by decreasing the pressure over the
composition or increasing both the pressure and temperature and
then condensing the vapors. This alternative means for recovering
hydrogen fluoride may be accomplished at pressures of from about 60
to about 1 psia and temperatures of from about 20 to about
50.degree. C. As yet another alternative, hydrogen fluoride value
may be recovered from the treated compositions by use of the
compositions in any of the wide variety of processes that use
hydrogen fluoride.
EXAMPLES
[0075] The invention will be clarified further by a consideration
of the following examples that are intended to be purely
exemplary.
Example 1
[0076] Approximately, 0.5 grams of Stockosorb M
(acrylamide/potassium acrylate copolymer, cross-linked),
commercially available from Degussa AG, of Krefeld, Germany, was
placed into a perfluoroalkoxy (PFA) vessel fitted with a screen
above the polymer, and evacuated. The PFA vessel was then weighed,
and cooled to about -78.degree. C. About 29 grams of anhydrous HF
were distilled onto the polymer. The PFA vessel was warmed to room
temperature and weighed. After about two hours, the PFA vessel was
inverted and the excess HF drained into a second, evacuated PFA
vessel. The HF-polymer gel remained on the filter screen in the
first PFA vessel. The vessel containing the polymer gel was again
weighed and the polymer found to have absorbed about 45.6 grams of
HF per gram of polymer. This experiment was repeated several times
and the average capacity was found to be about 45.2 grams of
anhydrous HF per gram of polymer, which is reported in Table 1.
Examples 2-4
[0077] The procedure in Example 1 was repeated for Examples 2-4,
except that Stockosorb
[0078] M was substituted for Stockosorb CW, FW, and SW,
respectively. The results for each composition are reported in
Table 1.
Example 5
[0079] The procedure in example 1 was hard to perform with small
particle sized polymers and had unacceptable scatter in the
results, so a different approach was taken to characterize their
capacity. Approximately 0.5 grams of Stockosorb CW was placed in a
PFA vessel, connected to a vessel containing HF, and the system was
evacuated. The valve of the HF container was opened and the polymer
allowed to absorb HF vapor for two days. At the end of this period
the polymer had adsorbed 37.62 grams of HF/gram of polymer. The
experiment was repeated with fresh polymer which was allowed to
absorb HF vapor for about 4 days. At the end of this period the
polymer had adsorbed 40.90 grams of anhydrous HF per gram of
polymer. The average of these two measurements is reported in Table
1. Although this technique is different than the approach described
in example 1, it shows the polymer absorbs much more HF than
previously reported systems.
Example 6
[0080] The procedure in example 2 was repeated with Stockosorb FW.
The average of multiple runs for each composition is reported in
Table 1.
[0081] Comparative Examples 7-15
[0082] The procedure in example 1 was repeated, except with the
polymers listed Table 1. The HF capacities of these polymers is
summarized in Table 1. The test results show that
acrylamide/potassium acrylate cross-linked copolymers have a much
higher HF capacity compared to acrylate polymers.
Example 16
[0083] A small amount of Stockosorb M was placed into a previously
weighed FEP vessel. The vessel was evacuated and weighed again to
determine the weight of polymer (0.1111 grams). The sample was then
reconnected to the metal vacuum line, cooled to -78 .degree. C. and
an excess of HF distilled onto the polymer. The weight of the
vessel+polymer+HF was then obtained. The vapor pressure of this
system was measured at 20 .degree. C. A small amount of HF was then
distilled from the vessel and the weight of the vessel+polymer+HF
was then obtained. The vapor pressure of this reduced HF system was
again measured at 20 .degree. C. This procedure was repeated
multiple times until nearly all of the HF had been removed. This
experiment was run in triplicate, the vapor pressures were then
calculated at several standard compositions and plotted in FIG. 1.
The results demonstrate the low vapor pressure of the
composition.
Example 17
[0084] Example 16 was repeated at 0.degree. C. The results are
shown in FIG. 1.
Example 18
[0085] Example 16 was repeated at 40.degree. C. The results are
shown in FIG. 1.
Example 19
[0086] Example 16 was repeated at 60.degree. C. The results are
shown in FIG. 1.
Example 20
[0087] About 8 grams of Stockosorb M was quickly added to a
cylinder containing about 180 grams of HF at 20.degree. C. In about
160 seconds the HF was about 65% gelled based on the height of the
expanding polymer in the cylinder. Shortly afterward, the HF was
completely gelled. The temperature of the cylinder contents reached
29.degree. C. before cooling to 20.degree. C. This test
demonstrates the rapid uptake of HF by the copolymer.
Example 21
[0088] Approximately, 0.49 grams of Stockosorb M
(acrylamide/potassium acrylate copolymer, cross-linked),
commercially available from Degussa AG, of Krefeld, Germany, was
placed into a perfluoroalkoxy (PFA) vessel fitted with a screen
above the polymer, and evacuated. About 78.8 grams of aqueous HF
(49 wt %) transferred onto the polymer. The PFA vessel was weighed.
After about two hours, the PFA vessel was inverted and the excess
HF drained into a second, evacuated PFA vessel. The HF-polymer gel
remained on the filter screen in the first PFA vessel. The vessel
containing the polymer gel was again weighed and the polymer found
to have absorbed about 72.5 grams of aqueous HF per gram of
polymer.
Comparative Example 22
[0089] About 150 grams of water was added to 0.5 grams of
Stockosorb M and allowed to sit for about 2 hours. The mixture was
then filtered. Based on the weight increase, the polymer absorbed
about 254 grams of water per gram of polymer.
Comparative Example 23
[0090] About 165 grams of deionized water was added to 0.58 grams
of poly(acrylic acid) partial sodium salt from Aldrich, mixed, and
filtered as in comparative example 14. The polymer absorbed about
231 grams of water per gram of polymer. The Stockabsorb M therefore
absorbed about 10% more water than this Aldrich polymer. Based on
these water examples the two polymers have very similar absorbent
capacities for water. It is therefore completely unexpected that
the Stockosorb absorbs about 22 times more HF than the Aldrich
polymer (Table 1).
Example 24
[0091] Polymer A, which quickly absorbs HF will be mixed with
polymer B which absorbs HF more slowly, but yields a gel with a
lower vapor pressure than polymer A. This polymer mixture will then
be added to HF. The resulting gel will form quickly and will have
an acceptably lower vapor pressure and reduced tendency to form HF
aerosol droplets.
Example 25
[0092] Polymer C, which quickly absorbs HF, will be mixed with
polymer D which absorbs
[0093] HF more slowly, but has a higher capacity for absorbing HF.
This polymer mixture will then be added to HF. The resulting gel
will form quickly and will have an acceptably high capacity for
HF.
Example 26
[0094] Polymer A, B, and D will be mixed and then added to HF. The
resulting gel will form quickly, will have a good capacity for
absorbing HF, an acceptably low vapor pressure, and a reduced
tendency to form HF aerosol droplets.
TABLE-US-00001 TABLE 1 Polymer Capacity (grams HF/gram polymer)
Avg. Value Ex. Avg. (vapor No. Value expt) 1 Stockosorb .RTM. M
(polyacrylate-polyacrylamide 45.20 cross-linked copolymer) 2/5
Stockosorb .RTM. CW (polyacrylate-polyacrylamide 52.72 39.26
cross-linked copolymer) 3/6 Stockosorb .RTM. FW
(polyacrylate-polyacrylamide 75.42 27.14 cross-linked copolymer) 4
Stockosorb .RTM. SW (polyacrylate-polyacrylamide 57.56 cross-linked
copolymer) 7 AQUAKEEP .RTM. (sodium polyacrylate) 3.50 8 Luquasorb
.RTM. 1030 (sodium polyacrylate) 2.50 9 Luquasorb .RTM. 1270
(potassium polyacrylate) 1.70 10 Luquasorb .RTM. 1210 (sodium
polyacrylate) 2.30 11 AP73 (cross-linked sodium polyacrylate) 1.50
12 Aldrich .RTM. Na.sup.+ salt (sodium polyacrylate) 1.90 13
Aldrich .RTM. K.sup.+ salt (potassium polyacrylate) 1.92 14 AP80HS
(sodium polyacrylate) 2.52 15 SXM 70 (salt of polyacrylic acid)
1.83
Example 27
[0095] An empty dry chemical-type fire extinguisher canister
equipped with a nozzle and a triggering mechanism will be provided.
The canister will be partially filled with binder comprising a
cross-linked copolymer comprising acrylamide units and acrylate
units. The canister will then be pressurized using a compressed
gas.
[0096] Liquid hydrogen fluoride will be poured into shallow pan.
The nozzle of the canister will be directed to the hydrogen
fluoride and the triggering mechanism activated. The binder will
then be released from the canister and propelled into contact with
the hydrogen fluoride.
[0097] Upon contacting the hydrogen fluoride, the binder will start
to form a gelatinous material comprising the copolymer and the
hydrogen fluoride. Within minutes, substantially all of the
hydrogen fluoride will be immobilized within the gelatinous
material.
[0098] Having thus described a few particular embodiments of the
invention, it will be apparent to those skilled in the art, in view
of the teachings contained herein, that various alterations,
modifications, and improvements not specifically described are
available and within the scope of the present invention. Such
alterations, modifications, and improvements, as are made obvious
by this disclosure, are intended to be part of this description
though not expressly stated herein, and are intended to be within
the spirit and scope of the invention. Accordingly, the foregoing
description is by way of example only, and not limiting. The
invention is limited only as defined in the following claims and
equivalents thereto.
* * * * *