Novel derivatives of MCM-36 as catalysts for the reduction of nitrogen oxides from FCC regenerator flue gas streams

Jan Olaf Barth, Andreas Jentys, Eleni F. Iliopoulou, Iacovos A. Vasalos, Johannes A. Lercher

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

MCM-36 materials containing mixed oxide pillars (MgO-Al 2O 3-MCM-36, BaO-Al 2O 3-MCM-36, MgO-Al 2O 3SiO 2-MCM-36, BaO-Al 2O 3SiO 2-MCM-36) were investigated as additives for the in situ reduction of NO x formed during the regeneration of coked cracking catalysts in FCC units. The additives were investigated under reaction conditions similar to the oxygen-depleted and the oxygen-enriched zone of the FCC regenerator. MCM-36-type materials with basic mixed oxide clusters in the interlayer galleries showed high NO conversions (∼85%) and high N 2 yields (∼80%) under oxygen-deficient reaction conditions. The catalytic activity of MCM-36 with alkaline earth metal aluminum oxide pillars incorporated between the zeolitic layers was higher (MgO-Al 2O 3-MCM-36: 77% N 2 yield at 650°C) compared to the nonpillared parent material MCM-22 (22%). The materials have been added in regeneration experiments to industrial (coked) FCC catalysts in a fluidized-bed reactor. The materials led to a reduction of NO emissions also in the presence of Pt-based CO combustion promoters (∼30% NO reduction). It is speculated that Brønsted acid sites in the zeolite layers of the composite materials catalyze the reduction of NO with NH 3, which is an intermediate in the regeneration of nitrogen-containing carbonaceous deposits on deactivated FCC catalysts.

Original languageEnglish
Pages (from-to)117-129
Number of pages13
JournalJournal of Catalysis
Volume227
Issue number1
DOIs
StatePublished - 1 Oct 2004

Keywords

  • Fluid catalytic cracking (FCC)
  • NO reduction
  • Oxidative regeneration
  • Pillared zeolites

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