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The CO‐catalyzed conversion of H 2 S to H 2 + sulfur part 2. The thermal decomposition of COS
Author(s) -
Faraji Farhad,
Safarik Imre,
Strausz Otto P.,
Yildirim Erdal,
Torres Manuel E.
Publication year - 1999
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450770113
Subject(s) - disproportionation , catalysis , thermal decomposition , decomposition , yield (engineering) , pyrolysis , sulfur , chemistry , atmospheric temperature range , hydrogen sulfide , hydrogen , product distribution , inorganic chemistry , sulfide , selectivity , analytical chemistry (journal) , materials science , thermodynamics , organic chemistry , metallurgy , physics
The pyrolysis of COS has been studied over the temperature range 300 to 750°C using a variety of catalysts. The observed product distribution confirmed that two parallel reaction paths: 2 COS → 2 CO S 2 (2) and 2 COS → CO 2 + CS 2 (4) are involved in the decomposition. The decomposition yield increased with rising temperature, accompanied with a shift in selectivity. At temperatures lower than ∼700°C the disproportionation reaction 4 was predominant, whereas at temperatures higher than 700°C, reaction 2 was favoured. In the high‐temperature region (700 to 750°C) it was possible to achieve full suppression of reaction 4 with added CS 2 . The pyrolysis of COS was also studied in a reactor packed with quartz chips without catalysts at high temperatures. Between 800 and 900°C, up to 99% conversion (with respect to the thermodynamic limit) could be achieved, with the almost complete absence of the disproportionation reaction 4. The results point to the commercial potential in the two‐step reaction sequence:\documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{\begin{array}{*{20}c} {2{\rm H}_2 {\rm S} + 2{\rm CO} \leftrightarrow 2{\rm COS} + 2{\rm H}_2 } \hfill \\ {2{\rm COS} \leftrightarrow 2{\rm CO} + {\rm S}_2 } \hfill \\ \end{array}}}{{2{\rm H}_2 {\rm S} \leftrightarrow 2{\rm H}_2 + {\rm S}_2 }} $$\end{document}for the economic conversion of hydrogen sulfide to hydrogen and sulfur.