Vitrification of Simulated Combustible Dry Active Wastes in a Pilot Facility

  • Published : 2001.08.01

Abstract

In order to evaluate and finally optimize the vitrification condition for combustible dry active waste (DAW), dust and gas generation characteristics were investigated for PE, cellulose, and mixed waste Tests were conducted by varying the operation variables such as melter configuration, excess oxygen amount, and waste feeding rate. Results showed that dust generation characteristics were affected by the operation parameters and the melter's configuration is the dominant one. For all tested DAWs, dust generation was reduced by increasing the waste feeding rate and the excessive oxygen amount in the melter. Among waste types, dust amount was decreased by the order of mixed wastes, PE, and cellulose. Other parameters such as temperature variation and operation time have also affected the dust generation. The optimum condition for the DAW vitrification was determined as the melter's configuration equipped for minimizing the waste dispersion with 20 kg/h of waste feeding rate and 100% of excessive oxygen supply. CO gas concentration in the off-gas was immediately influenced by the combustion state in the melter, but showed similar trend as the dust generation. For the NOx production during the vitrification process, thermal NOx, which is generated from the Post Combustion Chamber (PCC), rather than fuel NOx was assumed to be dominant. The gas cleaning of efficiencies of the PCC, wet scrubber, and Selective Catalytic Reduction system (SCR) were found to be high enough to keep the concentration of pollutants (CO, NOx, SOx, HCI) in the stack below their relevant emission limits.

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References

  1. 'Chlorine Input and Dioxin Emissions', www.ping.be/~ping5859/Eng/ChlorineDilnp.html
  2. K. H. Yang, et al., 'Characterization of Low- and Intermediate-Level Radioactive Wastes from Nuclear Power Plants in Korea', Proc. EPRI 2000 LILW Conference, Texas, USA, July 19-21 (2000)
  3. J. Bradley Mason, Vitrification Advances for Low Level Radioactive and Mixed Wastes, EPRI-TR-105569
  4. H. F. Mark, N. M. Bikales, C. G. Overberger, G. Menges. Encyclopedia of Polymer Science and Engineering, Vol. 3; John Wiley & Sons(1985)
  5. A. J. Downs and C. J. Adams, The Chemistry of Chlorine, Bromine, Iodine, and Astatine, 1st ed., Pergamon Press (1979)
  6. M.H. Langowski, J. G. Darab, and P. A. Smith, Volatility Literature of Chlorine, Iodine, Cesium, Strontium, Technetium, and Rhenium;Technetium and Rhenium Volatility Testing, PNNL-11052 (1996)
  7. Technical Report Series No. 302, Treatment of off-Gas from Radioactive Waste Incinerators, International Atomic Energy Agency, Vienna (1989)
  8. Hermine N Soud and Kazunori Fukasawa, Developments in NOx abatement and control', IEACR/89 (1996)