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EXECUTIVE SUMMARY 19 The molten metal furnace is capable of handling metal parts and energetics, but pilot plant work is required. Plasma arc furnaces might also handle these materials but may not be as useful for large metal parts. Further development of this approach is also required. All of these processes could also be used to destroy bulk agent. Treatment of all streams in one device offers equipment simplification but with some loss of control of the composition of the feed streams and the products resulting from destruction of the several streams. Afterburners For all systems that produce waste gas, afterburners are needed to ensure complete oxidation. The baseline practice is to use internal firing with fuel if additional heat is needed. Substituting oxygen for air and external heating for internal firing would minimize waste gas, but the first option would require demonstration. Catalytic oxidation could reduce the temperatures required, but the use of highly active catalysts is made difficult by the deactivation potential of the P, F, C1, and S content of the agents. Molten salt systems might also serve as afterburners as well as for acid gas removal. Another variation would be to complete gas oxidation by supercritical water oxidation. In this approach, it would be necessary to compress the gas to 3,000 psi. With the use of afterburners, gas streams from any of the processes can be brought to specified levels of agent and destruction of organic material, which can be confirmed by storage and certification. Thus, waste gas purity can be ensured independently of the process used. GENERAL OBSERVATIONS 1. The risk of toxic air emissions can be virtually eliminated for all technologies through waste gas storage and certification or treatment by activated-carbon adsorption. Either of these options can be combined with methods to reduce the volume of gas emissions. Agent releases from accidents in the destruction facility and releases to the atmosphere of residual unreacted agent or toxic products from equipment malfunction can all be avoided for any alternative technology by applying a dosed system concept to all gas streams leaving the facilities. That is, gas streams can be stored until chemical analysis has demonstrated their compliance with regulatory standards. The storage volume needed to handle
EXECUTIVE SUMMARY 20 gaseous oxidation products can be made adequate to store any accidental release of vaporized agent from the destruction facility. Large activated-carbon (charcoal) adsorbers can perform much the same function. In this case, agent and products of incomplete combustion are captured and retained on the charcoal. The amount of gas released can be greatly reduced by the use of pure oxygen in destruction processes instead of ordinary nitrogen diluted air. Waste gas can be further reduced by capturing the carbon dioxide it contains with lime, as well as capturing HCl, HF, SO2, and P 2O5 , at the cost of increasing the amount of solid waste produced. These techniques can be applied to all technologies. 2. There are many possible destruction processes. A wide variety of processes have been proposed to replace or augment components of the current baseline destruction system. The scope of possible modifications ranges from simply replacing one component, such as the agent combustion process, to replacing all current combustion-based processes. New components would likely require 5 to 12 years for research and demonstration, the lower figure representing the time required for construction and testing of demonstration facilities, the higher figure including research and pilot plant work as well. 3. Initial weapons disassembly and agent detoxification and partial oxidation could meet international treaty demilitarization requirements and eliminate the risk of catastrophic agent releases during continued storage. The strategy of disassembling weapons and applying liquid-phase processes to destroy agent can meet treaty demilitarization requirements. By destroying the stored agent, the risk of catastrophic agent release during storage is avoided. Final disposal of the wastes generated would be delayed until complete oxidation processes are developed. 4. There are a number of promising chemical processes for agent detoxification or oxidation. Chemical techniques could allow agent detoxification in low-temperature, aqueous systems. The reaction products could be confined and tested to determine whether further processing is needed to meet demilitarization requirements and also for suitability for release to a disposal facility or to local storage. The best results with such processes have been
EXECUTIVE SUMMARY 21 seen in GB destruction. Although there are laboratory leads for similar VX and mustard treatments, this work is at the early laboratory stage. The combined use of peroxysulfates and hydrogen peroxide shows promise for detoxification of agent and also for complete oxidation of its organic components. Biological and electrochemical processes might be used to further oxidize liquid wastes from detoxification processes, but they are in an early stage of research. 5. Processes used in combination with an afterburner can be used to oxidize agent. Processes proposed for oxidation of agent or of products from its chemical detoxification include wet air and supercritical water oxidation, molten salt oxidation, fluidized-bed combustion, steam gasification, plasma arc (electric arc) furnaces, and molten metal baths. All require an afterburner to complete oxidation, and all are promising but would require development and demonstration. 6. There are technologies to replace the baseline metal parts furnace. Alternative technologies to destroy energetics and reliably detoxify metal parts and containers involve heating to high temperatures. Using electrically heated ovens in place of the baseline internally fired kilns would reduce the amount of flue gas produced. Molten metal or salt baths could also treat these stockpile materials. Like the combustion-fired kilns, all these approaches require the use of afterburners to ensure complete oxidation. 7. Afterburner technologies might be used to control waste gas purity. Alternative afterburner options include external heating, catalytic combustion, molten salt or supercritical water oxidation. Afterburners can be designed to meet requirements for contaminant oxidation for both baseline and alternative processes and are essential in control of waste gas purity.
