Economical Disposal of Municipal Solid Waste with Minimal Discharges to the Atmosphere and Maximum Recycling of Energy and Metal Values.

摘要

A process has been developed at Brookhaven National Laboratory for the disposal of municipal solid wastes with minimal discharges to the atmosphere and maximum recycling of the energy and metal values contained therein. The energy values are recovered as zero ash, zero sulfur, zero nitrogen, zero chlorine particulate carbon (carbon black) fuels and a hydrogen-rich (or methane-rich) gaseous co-product. The process is especially adaptable to the disposal of plastic wastes and recycling of its energy values. Also, the inclusion of medical wastes should be no problem. The process consists of hydrogasifying prepared MSW (or any carbonaceous feedstock) to form a methane-rich process gas, which is then thermally decomposed (cracked) to form the primary product, carbon black, and hydrogen which is recycled to the hydrogasifier. Oxygen in the MSW is presently removed as water from the hydrogasifier effluent before it enters the methane decomposer. Any remaining hydrogen in the MSW feed is ultimately removed from the process as a co-product gas as hydrogen per se and/or methane (SNG). Chlorine in feed containing PVCs, for example, is removed as relatively minute amounts of hydrogen chloride in the condensed water discharged from the recuperative partial condenser. Desulfurization is not required to produce sulfur-free carbon black per se. Various options are available for desulfurization of the co-product gas. Since the process operates under a highly-reducing hydrogen atmosphere, toxic oxygenated compounds such as dioxins cannot form and metals entering with the MSW are removed with the ''ash'' as metals, not oxides.