Catalyst system and method for the catalytic combustion of ammonia to form nitrogen oxides in a medium-pressure system

US12378115B2 · kind B2 · utility

Assignee

• HERAEUS DEUTSCHLAND GMBH & CO. KG · DE

Inventors

• Willi Boll · Hanau, DE
• Dirk Maier · Hanau, DE

Key dates

• Filing date: Jan 9, 2020
• Grant date: Aug 5, 2025
• Expiry date: Apr 17, 2042

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Known catalyst systems for the catalytic combustion of ammonia to form nitrogen oxides consist of a plurality of single- or multilayer catalyst gauzes warp-knitted, weft-knitted or woven from platinum-based noble metal wire, which, when arranged one behind the other in a fresh gas flow direction, form a front group of gauze layers and at least one downstream group of gauze layers arranged after the front group. To provide from this starting point a catalyst system for use in a medium-pressure plant for ammonia oxidation, with which a high service life and a high yield of the main product NO can be achieved, it is proposed that the front group comprises a gauze layer or a plurality of gauze layers made of a first, rhodium-rich noble metal wire, wherein the gauze layer or one of the gauze layers made of the rhodium-rich noble metal wire is a front gauze layer facing the fresh gas, and that the downstream group comprises gauze layers made of a second, rhodium-poor noble metal wire, wherein the rhodium content in the rhodium-rich noble metal wire is at least 7 wt. % and no more than 9 wt. % and is at least 1 percentage point higher than the rhodium content in the rhodium-poor noble met…