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APPLICATION OF ALTERNATIVE TECHNOLOGIES TO THE DESTRUCTION OF THE U.S. CHEMICAL WEAPONS 192 STOCKPILE In steam-reforming 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 Cl) require oxidation and removal. The gas formed, after purification, can be a generally useful fuel; however, destroying it may be more practical, as is proposed for the products from pyrolysis. Steam reforming is more limited than pyrolysis because it does not appear directly useful for metal decontamination. However, combined pyrolysis and steam gasification is under private development for possible 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 than are the fast- response gaseous system of conventional combustion. These alternative methods also provide good contact between air and fuel. There would be some tendency for bubble formation to result in bypassing of agent through the combustion zone; thus, afterburners are still needed. These systems can also retain much of the oxidized halogens, sulfur, and phosphorus if appropriate basic acceptors are part of the salt or solids system. They can also manage energetics of small-particle size, although their ability to handle metal parts seems limited. Both molten salt and fluidized-bed systems are used for toxic waste disposal, and it would probably be possible to proceed directly to design and construction of a demonstration unit for demilitarization applications. Molten salt designs might also be used as afterburners and for acid gas removal from gaseous waste streams. The catalytic fixed bed is of special interest for use as an afterburner for the final oxidation of any unoxidized material in gas effluents from an agent destruction process. The familiar automobile catalytic converter is an example of this application. The presence of halogens, phosphorus, and sulfur in the agent and the presence of products from energetics destruction will probably preclude the use of very active catalysts. However, operation at higher temperatures could allow use of rugged catalysts or even common ceramics. For many situations, external heat (electrical) will minimize the need for internal firing to generate heat in the catalytic oxidation unit, thus reducing the production of waste gas. An important variation on all these high-temperature oxidation systems is their operation with pure oxygen instead of air. As discussed below, the volume of waste gas can be greatly reduced (or almost eliminated for some
