Experiments with a lime slurry in a stirred tank for the fixation of carbon-14-contaminated CO/sub 2/ from simulated HTGR fuel reprocessing off-gas
The fixation of CO/sub 2/ with a lime slurry in a stirred tank reactor appears to be feasible. The rate of reaction is fast, and virtually complete removal of CO/sub 2/ can be attained. At a gas residence time of <1 min, the decontamination factor (DF) is >100 in a single stage reactor for CO/sub 2/ concentrations ranging from 5 to 100%. It has been determined that two-stage contacting sequences which result in a cumulative DF > 10/sup 4/ are feasible. The reaction rate is constant up to 90% utilization of the lime and then rapidly decreases, as does the pH for the remainder of the reaction. The reaction appears to be liquid-phase-controlled, and the overall gas-side mass transfer coefficient (K/sub G/..cap alpha..) increases with impeller speed and gas flow rate, ranging from 0.4 x 10/sup -6/ to 6 x 10/sup -6/ g-moles of CO/sub 2/ per (cm/sup 3/-sec-atm). The reaction rate data are also correlated by a model of mass transfer accompanied by a fast pseudo first-order chemical reaction from which good agreement of calculated and predicted interfacial area is obtained. It was noted that temperature (21 to 46/sup 0/C) and lime concentration (0.5 to 1.5 M) had very little effect on mass transfer rate and DF. The settling rate of the CaCO/sub 3/ product increased significantly with impeller speed and temperature and decreased with gas flow rate. Scale-up calculations indicate that reasonably sized equipment would provide adequate removal of CO/sub 2/ for a full-scale reprocessing plant.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5065862
- Report Number(s):
- ORNL/TM-5757
- Country of Publication:
- United States
- Language:
- English
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CARBON 14
RADIOACTIVE WASTE PROCESSING
FUEL REPROCESSING PLANTS
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CALCIUM CARBONATES
CALCIUM HYDROXIDES
CARBON DIOXIDE
HTGR TYPE REACTORS
SLURRIES
ALKALINE EARTH METAL COMPOUNDS
BETA DECAY RADIOISOTOPES
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CARBON ISOTOPES
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EVEN-EVEN NUCLEI
GAS COOLED REACTORS
GRAPHITE MODERATED REACTORS
HYDROGEN COMPOUNDS
HYDROXIDES
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LIGHT NUCLEI
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MIXTURES
NUCLEAR FACILITIES
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PROCESSING
RADIOISOTOPES
REACTORS
SUSPENSIONS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
YEARS LIVING RADIOISOTOPES
052001* - Nuclear Fuels- Waste Processing
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