Modeling a solvent extraction process for radioactive waste treatment with SPEEDUP{trademark}
SpeedUp{trademark} has been used to model a continuous counter-current solvent extraction process designed to remove cesium from a waste stream at the Savannah River Site. The SpeedUp software from ASPEN Technology, Inc. is an equation-based dynamic chemical process modeling package that has been found particularly convenient to use. SpeedUp allows the user to readily develop unique models of process unit operations that can be combined into a system flowsheet and solved in a time dependent form. Since many of the unit operations at the Savannah River Site are unique this framework is particularly convenient for their modeling needs. The material balance model described in this report was used to evaluate solvent extraction as a method for cesium removal from a radioactive waste stream. If cesium can be efficiently removed, the decontaminated waste stream can be disposed of as low-level radioactive waste in the existing Saltstone grouting facility at the site. The raffinate stream from the solvent extraction process containing the concentrated cesium in an aqueous solution would be sent to the high-level waste vitrification facility which has been operating at the site since 1995. Here the cesium would be incorporated into borosilicate glass with other high-level radioactive waste materials and poured into steel canisters along for permanent disposal. The solvent extraction process is modeled as a series of equilibrium stages. Within each stage, the distribution coefficients that partition dissolved materials between the aqueous and organic phases are user specified parameters. As an enhancement, the basic solvent extraction model was modified to include carryover of the aqueous phase into the organic stream and carryover of the organic phase into the aqueous stream. This version of the model was run to simulate the TRUEX process and model results were found to compare favorablywith those reported in the literature. The SpeedUp formulation is easy to extend to handle additional modifications such as solvent cleanup or direct linking to pre- and post-processing steps used to treat the radioactive waste streams. The SpeedUp code is also very compact using just a generalized model of a single extraction stage and a macro that creates separate units (extraction, scrubbing and stripping) in the extraction process. The macro automatically builds each unit using as many stages as are specified in the operation section of the code.
- Research Organization:
- Savannah River Site, SC (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC09-96SR18500
- OSTI ID:
- 750103
- Report Number(s):
- WSRC-MS-99-00866; TRN: US0000618
- Resource Relation:
- Conference: Advanced Simulation Technologies Conference (2000), Washington, DC (US), 04/16/2000--04/20/2000; Other Information: PBD: 3 Dec 1999
- Country of Publication:
- United States
- Language:
- English
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