Rates of Ammonia Absorption and Release in Calcium Chloride

Collin Smith, Mahdi Malmali, Chen Yu Liu, Alon V. McCormick, E. L. Cussler

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


After synthesis, ammonia can be selectively absorbed by calcium chloride; nitrogen and hydrogen are not absorbed. The kinetics of release seem to be diffusion controlled. The kinetics of absorption are consistent with a first-order reaction after an initial period of a higher-order reaction, which may indicate a nucleation event. At 225 °C, both absorption and release show half-lives of around 10 min if the ammonia partial pressure is swung from 2 to 1 bar, which allows design of an absorber for the periodic separation of ammonia. When this absorber replaces the ammonia condenser in a conventional ammonia synthesis, the ammonia production at low pressure can have the same rate as the conventional process operating at higher pressure.

Original languageEnglish (US)
Pages (from-to)11827-11835
Number of pages9
JournalACS Sustainable Chemistry and Engineering
Issue number9
StatePublished - Sep 4 2018

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.


  • Absorption
  • Ammonia
  • Kinetics
  • Metal halide
  • Pressure swing absorption


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