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EXECUTIVE SUMMARY 12 High-Temperature, Low-Pressure Pyrolysis Some of the high-temperature pyrolysis and oxidation processes are capable of treating all major stockpile components (agent, energetics, and metal; see Table E-1). High temperatures are required to decontaminate metal parts and to ignite and destroy energetics (see Chapter 5). These temperatures must be sufficient to achieve the equivalent of the 5X criterion (treatment at 1000°F for 15 minutes) for metal decontamination. Kilns with electrical heating can meet these requirements and avoid dependence on the internal firing now used, an alternative approach that has the advantage of reducing total flue gas volume. However, air (or oxygen) must be supplied to oxidize unburned pyrolysis products. This step can be achieved within the kiln or in a secondary burner. An afterburner would be needed to ensure complete oxidation. Variations of this system can accept bulk containers as well as energetics and small metal parts. Plasma arc torches, which generate ionized plasmas at temperatures of up to 12,000 K, are being developed to destroy toxic wastes. Molten metal processes are electrically heated melting furnaces adapted for hazardous waste disposal. Both approaches use electrical heat and operate at higher temperatures than ovens or kilns under oxygen-deficient conditions. They generally introduce air to burn the products resulting from the initial pyrolysis but still require an afterburner. In principle both can handle chemical warfare agents and fragmented energetics and metal parts; the molten metal system would likely be able to handle a larger range of material sizes than would the plasma arc systems. In steam gasification processes, steam is reacted with carbon-containing feed at high temperatures to produce a gas containing the combustible components hydrogen, carbon monoxide, soot, and low-molecular- weight hydrocarbons. Other elements (S, P, F, and C1) require oxidation and removal. Steam gasification is more limited than pyrolysis, since it does not appear directly useful for metal decontamination. However, an approach combining pyrolysis and steam gasification is under private development for use in hazardous waste destruction. High-Temperature, Low-Pressure Oxidation High-temperature, low-pressure oxidation is the current workhorse for destroying toxic waste materials. There are several variations of interest. Molten salt and fluidized-bed oxidation, because of the large heat capacity of the molten salt and the pulverized-solids bed, are less likely to suffer flame-out (flame extinction) than is the fast-response gaseous system of conventional combustion. These alternative methods also provide good contact