Adsorbents and adsorption models for capture of Kr and Xe gas mixtures in fixed-bed columns

Austin P. Ladshaw, Alexander I. Wiechert, Amy K. Welty, Kevin L. Lyon, Jack D. Law, Robert T. Jubin, Costas Tsouris, Sotira Yiacoumi

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Off-gases produced during the reprocessing of used nuclear fuel (UNF) include 129I2, 3HHO, 14CO2, 85Kr, and 135Xe, which are volatilized out into the off-gas. In order to meet regulatory requirements for reprocessing plant emissions, these gases must be captured and removed from the off-gas stream prior to off-gas emission. Of particular interest are the noble gases, Kr and Xe, which can be fairly difficult to remove from the off-gas due to their low chemical reactivity. Thus, this work is focused on utilizing engineered adsorbents, AgZ-PAN and HZ-PAN, to capture Kr and Xe from a mixed-gas stream at relatively low temperatures (191–295 K) and various flow rates (50–2000 mL/min). Isothermal data for Kr and Xe on each adsorbent are analyzed to produce the Langmuir parameters needed to model the mixture adsorption capacities at relevant temperatures using the Extended Langmuir model. Those parameters are then incorporated into a fixed-bed adsorption model developed in this work using the Mulitphysics Object-Oriented Simulation Environment (MOOSE). That model is used to simulate breakthrough times for Kr and Xe in packed columns of AgZ-PAN and HZ-PAN, ranging in length from 6 to 20 in., at relevant temperatures and flow rates. Breakthrough times varied from nearly instantaneous for Kr in AgZ-PAN to 30 h for Xe in HZ-PAN. After the developed model was validated by comparisons with experimental breakthrough data, the model framework was used to simulate the performance of multiple fixed-bed columns connected in series.

Original languageEnglish
Article number122073
JournalChemical Engineering Journal
Volume375
DOIs
StatePublished - Nov 1 2019

Funding

The paper is dedicated to the memory of Veronica Rutledge of Idaho National Laboratory, who initiated the work on OSPREY. This research was supported by the Nuclear Energy University Program, Office of Nuclear Energy, U.S. Department of Energy. The authors are thankful to Professor Lawrence L. Tavlarides of Syracuse University and Dr. David W. DePaoli of the Oak Ridge National Laboratory for their valuable comments over the duration of the work. Special thanks to Mu Bai for his contribution to this work on the effect of pressure drop. Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). The paper is dedicated to the memory of Veronica Rutledge of Idaho National Laboratory , who initiated the work on OSPREY. This research was supported by the Nuclear Energy University Program, Office of Nuclear Energy, U.S. Department of Energy. The authors are thankful to Professor Lawrence L. Tavlarides of Syracuse University and Dr. David W. DePaoli of the Oak Ridge National Laboratory for their valuable comments over the duration of the work. Special thanks to Mu Bai for his contribution to this work on the effect of pressure drop.

Keywords

  • Adsorption
  • Finite elements
  • Modeling
  • Noble gases
  • Nuclear fuel recycling
  • Separations

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