Coal plasticity at high heating rates and temperatures. First technical progress report for the fourth quarter 1989

Darivakis, George S.; Peters, William A.; Howard, J.B.

doi:10.2172/10172746

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“…A sample of a clay soil rich in montmorillonite (10) was supplied by the University of Utah. At MIT (16), a 63-90-µm fraction, prepared by sieving, was contaminated by exposing the soil to a dichloromethane (DCM) solution of pyrene and allowing the solvent to evaporate at ambient conditions. Pyrene deposited on the outer surface of the soil particles and caused them to agglomerate.…”

Section: Methodsmentioning

confidence: 99%

“…The soil-pyrene mixture was ground to disperse the pyrene more uniformly. Weight loss of the resulting specimens upon DCM washing revealed a contamination level of 9.3 wt % based on uncontaminated soil (16). The soil moisture content was not determined but is probably no more than 1-2 wt % given that the weight loss from heating neat soil amounted to only 1-1.5 wt % at temperatures from 100 to 250 °C (Figure 1).…”

Section: Methodsmentioning

confidence: 99%

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Evaporation Phenomena during Thermal Decontamination of Soils

Gilot

Howard

Peters

1997

Environ. Sci. Technol.

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Effects of thermal treatment conditions on removal of a low volatility aromatic contaminant from soil are quantified. Shallow beds (10 mg) of a clay soil pretreated with 8 ( 0.4 wt % pyrene were heated in a thermogravimetric analysis at 5, 25, or 50 °C/min or isothermally. Effects of temperature, time, initial soil mass, initial contaminant mass, heating rate, and flow rate of carrier gas (helium at standard conditions) were studied, as were weight loss of uncontaminated soil and evaporation rates of pure pyrene. Extensive pyrene removal from foil (85-90%) was found between 200 (at 5 °C/ min) and 300 °C (at 50 °C/min). Soil decontamination was modeled as pyrene transport without chemical reaction, i.e., (1) evaporation from a liquid sheath encasing each soil particle; (2) diffusion through the soil pile; and (3) diffusion to the ambient through a concentration boundary layer between the soil pile and the top of the thermobalance crucible. Evaporation is important in removing most, i.e., 70% or more, of the pyrene. However, rates of pyrene release from the soil bed are about 5-fold lower than those for evaporation of pure pyrene. Pyrene evaporation is confined largely to thin zones that recede downward through the soil pile as decontamination proceeds.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%