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PROCESSES AT MEDIUM AND HIGH TEMPERATURES 137 7 Processes at Medium and High Temperatures Processes beyond those previously discussed might be applied to the destruction of the chemical weapons stockpile.1 In contrast to the liquid-phase processes reviewed in Chapter 6 that operate at low temperatures and atmospheric pressure, most of the technologies reviewed in this chapter operate under much more severe conditions. Many of these technologies, even the oxidative ones, produce gaseous waste streams that would require further oxidation in some form of afterburner. The technologies examined here can be grouped in the following categories: ⢠Moderate-temperature, high-pressure processes: Wet air and supercritical water oxidation are processes that occur in water at moderate temperatures and high pressures. ⢠High-temperature, low-pressure pyrolysis: Some technologies involve agent vaporization and decomposition upon heating. The gaseous products resulting from this pyrolysis will generally need to be oxidized further to destroy organic by-products of agent breakdown. Molten metal and plasma arc (electric arc) are such technologies and will be discussed below. Gasification and steam reforming are also in this category. ⢠High-temperature, low-pressure oxidation: One class of technologies, including catalytic fluidized-bed systems, molten salt, and catalytic oxidation, entails agent reaction with oxygen to produce carbon dioxide, water, gases, and other inorganic substances. ⢠Other processes: A hydrogenation process might be used to destroy agent or a sulfur process might be used to create a polymer while destroying agent. Reduction and pyrolytic processes will result in products that are themselves toxic, such as PH3 or H2S. These will require safe handling as well as final destruction to create stable products. 1 Much of the information presented in this chapter is based on presentations made at the committee's workshop (Appendix F).
