Decomposition of ammonia with iron and calcium catalysts supported on coal chars

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)685-692
Journal / PublicationFuel
Volume83
Issue number6
Publication statusPublished - Apr 2004
Externally publishedYes

Abstract

Decomposition of NH3 to N2 with Fe and Ca catalysts supported on brown coal chars has been studied with a cylindrical quartz reactor from a viewpoint of hot gas cleanup. The catalyst is prepared by pyrolyzing a brown coal with Fe or Ca ions added. In the decomposition of 2000 ppm NH3 diluted with He at 750°C and at a space velocity of 45,000 l/h, 2-6wt% Fe catalysts are more active than not only 6wt% Ca catalyst but also 8wt% Fe catalyst loaded on a commercial activated carbon. The transmission electron microscope observations show that fine iron particles with the sizes of 20-50 nm account for the higher catalytic performances. When reaction temperature is increased to 850°C, all of Fe and Ca catalysts on the chars achieve complete decomposition of NH3. The co-feeding of H2 with 2000 ppm NH3 improves the performance of the 2% Fe catalyst at 750°C, but contrarily the coexistence of syngas (CO/H 2=2) deactivates it remarkably, whereas the addition of CO 2 to syngas restores the catalytic activity of the Fe to the original state without syngas. The powder X-ray diffraction and temperature programmed desorption measurements strongly suggest that the Fe and Ca catalysts promote NH3 decomposition through cycle mechanisms involving the formation of N-containing intermediate species and the subsequent decomposition to N2. © 2003 Elsevier Ltd. All rights reserved.

Research Area(s)

  • Ammonia decomposition, Calcium catalyst, Hot gas cleanup, Iron catalyst

Bibliographic Note

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Citation Format(s)

Decomposition of ammonia with iron and calcium catalysts supported on coal chars. / Ohtsuka, Yasuo; Xu, Chunbao; Kong, Dapeng et al.
In: Fuel, Vol. 83, No. 6, 04.2004, p. 685-692.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review