Pillared interlayered clay catalysts for the selective reduction of nitrogen oxides with ammonia

US5415850A · kind A · utility

Assignees

• The Research Foundation of the State University of New York · US
• Electric Power Research Institute, Inc. · US

Inventors

• Ralph T. Yang · Middle Island, US
• J. Edward Cichanowicz · Saratoga, US

Key dates

• Filing date: Feb 24, 1993
• Grant date: May 16, 1995
• Expiry date: Feb 24, 2013

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D53/8628
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Pillared interlayered clay catalysts (PILC) are formed and used in the selective reduction (SCR) of nitrogen oxides (NO.sub.x) in exhaust gases in the presence of ammonia. Cr.sub.2 O.sub.3 -PILC, Fe.sub.2 O.sub.3 PILC, TiO.sub.2 -PILC, ZrO.sub.2 -PILC and Al.sub.2 O.sub.3 -PILC each have considerable activities in the SCR of NO by NH.sub.3. Forming the catalysts in a bimodal pore structure provides increases poison resistance and increases reaction rates. Doping the catalyst with CeO.sub.2 and/or Ce.sub.2 O.sub.3 can promote increased activities. The PILC SCR catalysts do not oxidize SO.sub.2 to undesirable SO.sub.3 in any detectable amount.