Selective catalytic reduction of nitrogen oxides

US5552128A · kind A · utility

Assignee

• Mobil Oil Corporation · US

Inventors

• Clarence D. Chang · Princeton, US
• Jose G. Santiesteban · Baton Rouge, US
• David S. Shihabi · Pennington, US
• Scott A. Stevenson · Houston, US
• James C. Vartuli · West Chester, US

Key dates

• Filing date: Mar 24, 1995
• Grant date: Sep 3, 1996
• Expiry date: Mar 24, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B21/02
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

There is provided a catalytic method for converting nitrogen oxides to nitrogen (i.e., N.sub.2). The catalyst for this method comprises an acidic solid component comprising a Group IVB metal oxide modified with an oxyanion of a Group VIB metal and further comprising at least one metal selected from the group consisting of Group IB, Group IVA, Group VB, Group VIIB, Group VIII, and mixtures thereof. An example of this catalyst is zirconia, modified with tungstate, and iron. This method may be used for reducing emissions of nitrogen oxides from waste gases, including industrial exhaust gases and automobile exhaust gases. In a particular embodiment, nitrogen oxides in waste gases may be reacted with ammonia before the waste gases are discharged to the atmosphere.