Abstract:
The invention provides methods and a reactor for safely destroying containers having toxic chemical and biological materials contained therein. The reactor comprises a pressure vessel having an internal reaction chamber and at least one heater disposed on an exterior of the pressure vessel. A fragment-suppression system is also disposed within the internal reaction chamber. The fragment-suppression system is adapted to receive a container therein, such as an energetic chemical munition, and is adapted to receive a charge for opening the container. An injection port is also provided so that oxidants can be injected into said reaction chamber to neutralize the chemical and biological materials after the container has been opened.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured, used, and/or licensed by or for the Government of the United States of America without the payment of any royalties thereon or therefor. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to oxidation of chemical or biological materials. More particularly, this invention provides a system useful for oxidizing and neutralizing chemical and biological materials housed within containers, for example, energetic or non-energetic chemical munitions. 
     BACKGROUND OF THE INVENTION 
     Frequently, chemical or biological materials are contained in containers, such as a casing of an energetic or non-energetic munition, or containers containing Chemical Agent Instruction Sets (CAISs) which were used by the military as training aids to help prepare military personnel for chemical weapon attacks. In order to neutralize or destroy the chemical or biological materials, the containers are often opened in a protective enclosure using shape charges, for example. This may cause the burster used in energetic munitions to either burn or detonate. The contents are then neutralized using reagent neutralizers. However, many existing systems require a priori information or knowledge of the chemical or biological agent housed in the container so that a proper neutralizer can be used. Moreover, even after using the neutralizer the neutralized chemical or biological agents may still require post processing, such as incineration, to meet environmental regulations and laws. 
     Supercritical water oxidation (SCWO) is a process capable of destroying nearly all chemical and biological materials through oxidation. Supercritical water oxidation avoids the need for incineration and does not require a priori knowledge of the chemical or biological agent being destroyed. Supercritical water oxidation uses supercritical water, i.e., water at a temperature greater than 705.2 degrees Fahrenheit and a pressure greater than 3,200 psia. Supercritical water has a liquid-like density and a gas-like viscosity. Organic materials and gases become highly soluble in supercritical water, whereas inorganic materials are essentially insoluble. When oxygen is introduced, the organic materials are oxidized almost instantly, leaving only materials such as water and inorganic ions. 
     Many supercritical water oxidation systems use a continuous-feed or a steady-flow reactor. This involves adding water, an oxidizer, and the material to be destroyed or oxidized (the reactants) at inlets of the reactor, heating the reactants as they flow through the reactor, managing the heat of combustion, and collecting the products of the reaction at an outlet of the reactor. One problem with this is that when inorganic solids are present or are produced during the reaction, these solids frequently plug the reactor. Moreover, continuous-feed reactors typically do not provide an easy way to reprocess products that are not fully oxidized. Continuous-feed reactors are usually large, expensive, and complex, and tend to be fixed facilities due to their size. Further, continuous-feed reactors are not easily adapted for opening containers using shape charges or the detonation of energetic munitions. 
     Supercritical water oxidation processes can also be performed in batch reactors. Batch reactors typically involve using a pressure vessel in which the reactants are heated at a fixed pressure-vessel volume. That is, there are no flows into or out of the pressure vessel during heating. One batch reactor includes a heating element that projects into a central region of an interior of a pressure vessel for heating the reactants. The reactants in the central region are heated to supercritical conditions, while walls of the vessel are cooled, forming a subcritical region adjacent the walls. This establishes an internal circulation between the supercritical central region and the subcritical near-wall region that reduces corrosion of the walls and promotes rapid oxidation in the supercritical central region by constantly moving reactants into this zone while removing reaction products. However, batch reactors of this type are not easily adapted for opening containers using shape charges or the detonation of energetic munitions. 
     For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternatives for oxidizing chemical or biological materials that are contained within containers. 
     SUMMARY 
     The above-mentioned problems with oxidizing chemical or biological materials that are housed within containers and the difficulties of destroying energetic munitions are addressed by the present invention and will be understood by reading and studying the following specification. 
     Embodiments of the present invention provide a reactor capable of opening a container, such as an energetic or non-energetic munition containing a biological or chemical material, and oxidizing the biological or chemical material contained therein. 
     For one embodiment, the invention provides a reactor with a pressure vessel having an internal reaction chamber. At least one heater is disposed on an exterior of the pressure vessel. A fragment-suppression system is disposed within the internal reaction chamber. The fragment-suppression system is adapted to receive a container therein and is adapted to receive a charge for opening the container. 
     Further embodiments of the invention include methods and apparatus of varying scope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a reactor according to an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of the reactor of  FIG. 1 . 
         FIG. 3  is a view taken along line  3 - 3  in  FIG. 2 . 
         FIG. 4  illustrates a feed-through assembly according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, electrical, or other physical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims and equivalents thereof. 
       FIG. 1  is a perspective view illustrating a reactor  100  mounted on a portable platform  102 , such as a skid, a trailer bed, etc., according to an embodiment of the present invention.  FIG. 2  is a cross-sectional side view of reactor  100 . In one embodiment, reactor  100  destroys chemical or biological materials through oxidation, e.g., of an energetic or non-energetic chemical or biological munition or the chemical materials of a Chemical Agent Instruction Set (CAIS). 
     Reactor  100  includes a pressure vessel  110 . Pressure vessel  110  has an internal reaction chamber  112  located within a body  114  of pressure vessel  110  and a cover  116  that removably and repeatedly seals against body  114  via a seal  115  disposed between cover  116  and body  114 . For one embodiment, pressure vessel  110  is capable of operating at temperatures and pressures exceeding the critical temperature (about 705.2° F.) and pressure (about 3200 psia) of water and is capable of withstanding a pressure shock induced by detonation of an energetic munition of the type used for chemical or biological munitions. For example, pressure vessel  110  may comprise an ASME (American Society of Mechanical Engineers) pressure vessel that is ASME code stamped for 4900 psig at 1200° F. In addition, seal  115  may comprise a 718 Inconel GRAYLOC seal, manufactured by GRAYLOC Products, Houston, Tex., USA. For another embodiment, a clamp  118 , such as a C-clamp, clamps cover  116  to body  114 , squeezing seal  115  therebetween. For some embodiments, a hinge  120  pivotally attaches cover  116  to platform  102 , as illustrated in  FIG. 1 . Clamp  118  may also be attached to platform  102 , as shown in  FIG. 1 . In another embodiment, end cap  117  may be replaced by another cover, such as described for cover  116 , so that reactor  110  may be opened at either end. 
     For one embodiment, heaters  122  are disposed on an exterior surface of body  114 , as shown in  FIG. 2 , so as to make contact therewith. Heaters  122  can be ceramic band heaters, inductive heaters, or the like. For another embodiment, heaters  124 , such as cartridge heaters, are embedded in cover  116 , as shown in  FIG. 2 . In a preferred embodiment, each of heaters  122  and  124  can be individually controlled. 
     A fragment-suppression system  126  is contained in chamber  112 , as shown in  FIG. 2 .  FIG. 3  is a view of fragment-suppression system  126  taken along line  3 - 3  in  FIG. 2 . Fragment-suppression system  126  includes a fragment suppression tube  128  disposed on a stand  130  that is mounted on an interior surface of body  114 , as shown in  FIGS. 2 and 3 . In one embodiment, fragment suppression tube  128  is open at each of its ends  132 , as shown in  FIG. 2 . Fragment suppression tube  128  may comprise any material capable of absorbing or mitigating blast fragments or shrapnel creating by an exploding munition. For some embodiments, stand  130  is of a ceramic material or any other such non-corrosive material. For one embodiment, stand  130  comprises a series of ceramic disks (not shown). 
     For another embodiment, a container support  134  is disposed within fragment suppression tube  128  on an interior of the fragment suppression tube  128 , as shown in  FIGS. 2 and 3 . Container support  134  is adapted to receive a container  136  containing a biological or chemical material destined for destruction by reactor  100 , such as an energetic munition having a burster  138  or a non-energetic munition, or a container containing Chemical Agent Instruction Sets (CAISs), etc., as shown in  FIGS. 2 and 3 . Container support  134  is further adapted to receive an explosive charge  140 , such as a linear-shaped charge, so that charge  140  is disposed between container stand  134  and container  136 , as shown in  FIGS. 2 and 3 . For one embodiment, charge  140  is disposed in a groove  142  of container stand  134 , as shown in  FIG. 3 . In a preferred embodiment, a blast plate  156  is disposed between fragment-suppression system  126  and an interior surface of cover  116 , as shown in  FIG. 2 . For various embodiments, the charge  140  and container support  134  are adapted so that the charge  140  opens the container, accesses the burster  138 , and initiates oxidation of a charge of the burster  138  and the contents of the container. 
     A feed-through assembly  144  passes from internal chamber  112  through cover  116  to an exterior of reactor  100 , as shown in  FIG. 2 .  FIG. 4  illustrates feed-through assembly  144  without cover  116  according to another embodiment of the present invention. Feed-through assembly  144  has a fitting  146 , shown in  FIGS. 2 and 4 , having a threaded taper  148  that threads into cover  116  at an interior surface of cover  116 . Electrical wires  150  are electrically connected to charge  140  and pass through a tube  152  of feed-through assembly  144  to the exterior of reactor  100 , as shown in  FIGS. 2 and 4 . A seal  154 , such as a gland seal, e.g., of polyethylene, disposed in fitting  146  seals tube  152  and thus electrical wires  150  to prevent fluids from escaping from chamber  112  during operation of reactor  100 . For one embodiment, feed-through assembly  144  is available from CONAX Buffalo Technologies, Buffalo, N.Y., USA. For another embodiment, fitting  146  is located between blast plate  156  and cover  116 , as shown in  FIG. 2 , and wires  150  pass through blast plate  156 . Feed-through assembly  144  can withstand the high voltages required for detonating charge  140  and contains a minimal amount of organic materials that can consume oxygen that can otherwise be used for oxidizing chemical or biological materials. 
     In another embodiment, a pressure relief device  158 , such as a rupture disc, e.g., available from Oseco, Inc., Broken Arrow, Okla., USA, is disposed on end cap  117 , as shown in  FIG. 2 , for protecting reactor  100  against over pressure. A temperature sensor  160 , such as a thermocouple probe or the like, passes through end cap  117  for one embodiment. Reactor  100  also includes a sealable injection port  162 , e.g., in end cap  117 , as shown in  FIG. 2 . For other embodiments, a relief device  158 , a temperature sensor  160 , and/or a sealable injection port  162  can be located at other locations on pressure vessel  110  in addition to or instead of at end cap  117 , such as at cover  116 . 
     To oxidize a chemical or biological material using reactor  100 , container  136  containing the chemical or biological material is disposed within fragment-suppression system  126  so that charge  140  is adjacent to or is in contact with container  136 , as shown in  FIG. 3 . Reactor  100  is then sealed and leak tested. For one embodiment, leak testing involves adding helium to chamber  112 , e.g., through injection port  162 , and checking for helium leaks. After the helium leak rate is determined to be below an established criterion, the helium is removed from chamber  112  through exit ports (not shown) in reactor  100 . 
     A mixture of an oxidant, e.g., hydrogen peroxide, and water is injected into chamber  112  through injection port  162 . For one embodiment, the mixture is about 35 percent hydrogen peroxide and 65 percent water. For another embodiment, a base, such as calcium peroxide, magnesium peroxide, or sodium percarbonate is added to the mixture of water and oxidant to reduce corrosion. A controlled amount of the aqueous hydrogen peroxide solution is injected into chamber  112  for determining the pressure in pressure vessel  110 , via the water fraction. Hydrogen peroxide eliminates problems of handling gaseous oxygen. The base provides a counter ion for the acids to reduce corrosion and adds more oxygen for treating more chemical or biological material. 
     Electrically activating or detonating charge  140  by supplying electrical power to a detonator (not shown) on the charge  140  via electrical wires  150  opens container  136 , releasing the chemical or biological agent within container  136  into chamber  112 . For one embodiment, charge  140  produces a jet of molten metal that cuts open container  136 . In addition, where container  136  is an energetic munition having the burster  138 , activating charge  140  causes the burster to detonate or deflagrate resulting in an explosion of container fragments that are contained by fragment suppression tube  128  of fragment-suppression system  126 . In this way, fragment-suppression system  126  acts to protect the interior of pressure vessel  110  from exploding container fragments. Moreover, fragment-suppression system  126  is designed to remain in tact and at its fixed location within pressure vessel  110  as the container is opened by detonating the charge  140 , i.e., during the explosion of the container fragments, so that fragment-suppression system  126  or fragments thereof do not impact the interior of pressure vessel  110 . For another embodiment, the jet of molten metal produced by charge  140  accesses the burster and initiates oxidation of the charge of the burster. 
     After opening container  138 , heaters  122  and  124  are activated to heat the contents of chamber  112  to a temperature above the critical temperature and pressure of water to initiate a supercritical water oxidation process for oxidizing the biological or chemical material contained in chamber  112 . For one embodiment, the contents are heated to a temperature between about 1000° F. and about 1100° F. and a pressure between about 3900 psig and about 4200 psig. For some embodiments, the temperature and pressure are maintained at these levels for about 60 minutes to produce environmentally benign materials, such as water, carbon dioxide, sulfur oxide, nitrogen, chloride, and phosphate. Reactor  100  is subsequently cooled to about ambient temperature, and the contents of chamber  112  are sampled to verify that the biological or chemical material is completely oxidized. For one embodiment, this involves sampling a vapor phase for excess oxygen, e.g., using an oxygen sensor, and an aqueous effluent, e.g., water and non-organic salts, for total organic compounds. Sampling can be done through any access port, for example, injection port  162 . Typically, an acceptable level of total organic compounds is about 50 ppm. The vapor phase can then be removed by passing it through a carbon filter and the aqueous effluent is drained from reactor  100 . If the biological or chemical material is not completely oxidized the contents of chamber  112  are reheated to reinitiate the super critical water oxidation process. Sampling and reheating is repeated until complete oxidation of the chemical or biological material occurs. The cover can then be opened and any solid container fragments removed. For one embodiment, any solids that are removed meet U.S. Army 5X decontamination criteria, meaning commercial recyclers or disposal contractors can handle the solids without further decontamination. 
     In one embodiment, after opening container  136 , but before heating the contents of chamber  112 , electrical wires  150  are severed, exteriorly of reactor  100 , from a power source that supplied the electrical power to charge  140 , and feed-through assembly  144  is closed, e.g., by a plug or cap, at an exterior of cover  116 . This acts to seal feed-through assembly  144  during heating, because in some embodiments, seal  154  of feed-through assembly  144  may be damaged during heating. 
     CONCLUSION 
     Embodiments of the present invention provide a reactor capable of opening a container such as an energetic or non-energetic munition containing a biological or chemical material and oxidizing the biological or chemical material. The reactor can also safely treat Chemical Agent Instruction Sets (CAISs) without first opening or breaking the vials of the CAISs containing various chemical agents. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. Many adaptations of the invention will be apparent to those of ordinary skill in the art. Accordingly, this application is intended to cover any modifications, adaptations or variations of the invention. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof.