Kinetics of hydrocarbon and pesticide removal from clay soils during thermal treatment in a pilot-scale rotary kiln
- Univ. of Utah, Salt Lake City, UT (United States). Dept. of Chemical and Fuels Engineering
- Reaction Engineering International, Salt Lake City, UT (United States)
- Ciba-Geigy Corp., Tarrytown, NY (United States)
The kinetics of hydrocarbon removal from contaminated clay soils during thermal treatment in rotary kilns were studied experimentally, and kinetic parameters were obtained for simple first-order models. Results are given for seven hydrocarbons: toluene, naphthalene, n-hexadecane, lindane ({gamma}-HCH or 1,2,3,4,5,6-hexachlorocyclohexane), DDT (1,1{prime}-(2,2,2-trichloroethylidene) bis [4-chlorobenzene]), DDD (1,1{prime}-(2,2-dichloroethylidene) bis [4-chlorobenzene]), and DDE (1,1-dichloro-2,2-bis [p-chlorophenyl] ethylene). The activation energies ranged from 18 kJ/mol for toluene on wet soil, to 90 kJ/mol for the chlorinated pesticides. All the kinetic data were obtained in a 130 kW pilot-scale rotary kiln. The wall temperature of the kiln was 700 C for the pesticides. Three of the hydrocarbons, toluene, naphthalene and n-hexadecane, were studied on both wet soil (5.0 and 8.5 wt%) and on oven-dried soil at temperatures ranging from 300 to 650 C in order to understand better the effects of water on desorption rates. Water increases the rate of desorption of toluene but decreases the rates for the heavier compounds. The pilot-scale data and correlations should be useful to those who are operating and/or designing rotary kilns to remediate soils thermally. A methodology for taking pilot-scale results and using them to estimate full-scale performance is given.
- OSTI ID:
- 260455
- Journal Information:
- Waste Management, Vol. 15, Issue 5-6; Other Information: PBD: 1995
- Country of Publication:
- United States
- Language:
- English
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