Lab-Scale Testing of Low-Temperature, Vacuum-Aided Thermal Desorption, to Certify Organic Sludge Waste for Transportation to a Designated Repository

摘要

This paper investigates vacuum-aided, low-temperature thermal desorption as a potential technology alternativernto incineration, to allow drums of transuranic- (TRU-) contaminated organic sludge wastes to be shipped to a designated offsiternrepository. The lab-scale tests were performed to provide information on temperature profiles and rates of volatilernorganic desorption that can be used to model a full-scale thermal desorption application, involving in situ thermal desorptionrnfrom a 208-l waste drum. Results indicate that reduced pressure can enhance the rate of thermal desorption from an organicrnsludge waste, while maintaining a temperature profile sufficient to prevent destruction of the waste packaging materialsrnsurrounding the waste. Results also indicate that the thermal desorption process cannot be simply modeled via a bulk liquidliquidrnmass-diffusion model, partly due to the varying temperature gradient within the sludge, which is expected to be greaterrnfor full-scale drum applications. Even with smaller lab-scale volumes, however, the calculated effective diffusivities are 90-rn180 times greater than predicted. The high effective diffusivities are expected to be due to micro boiling of the volatilernorganics within the simulated sludge. The results support the need for model development and/or testing of the vacuumaidedrnthermal desorption process at a full-scale condition.