TOPCAT - Taming recOnstruction and loss of Platinum metals in high temperature industrial CATalytic processes (completed)
One of the major routes for the utilisation of Norwegian Natural Gas resources, and general on the world scale is in the production of fertiliser (production approx. 100.000.000 ton/ year). Ammonia is produced from Natural gas, and ammonia oxidation over platinum-rhodium gauze catalysts at high temperatures and short contact times is one of the important steps in production of nitric acid a cornerstone in fertilizer production. This critical step is an energy intensive high temperature process in which a major challenge is continual loss of the valuable platinum metal from the catalyst.
About the project
During operation the catalytic material undergoes dramatic changes, including extreme reconstruction with formation of excrescences resembling cauliflowers and a continuous loss of noble metals through the gas phase. These changes in the material have significant economic implications on the industrial processes. The issue of surface reconstruction and catalyst modification under operating conditions is a generic issue for many catalytic processes. The present project aims at utilizing and building competence in reproducing the industrial conditions at lab scale and applying advanced surface characterization techniques tailor-made for the study of these types of changes. The goal is to make the knowledge and expertise more generally available by active dissemination through the involvement of the industrial partners. A central topic will be to assess whether the cauliflower shaped reconstructions are essential for the catalytic process or if they are merely a consequence of it, and also to determine the role of formation of noble metal oxides in the catalytic process. By developing the methods and applying the techniques needed for obtaining detailed insight into the processes behind the reconstruction and the factors affecting it, in addition to attaining a more general understanding of the surface reconstruction in such high temperature ammonia oxidation processes.
To understand the reconstruction and mechanism of loss of PGM metals during ammonia oxidation and the factors affecting it though increased competence in characterization of catalyst surfaces.
- Establish lab scale experimental facilities for evaluation of catalyst performance, aging of samples for characterization of reconstruction and to investigate window of stable operation.
- To establish an improved understanding of diffusion of platinum in rhodium and vice versa, their transport mechanism and study the structural properties of the bulk and surface of model samples at operating conditions.
- To establish an improved understanding of effects such as elemental composition, impurities and defects on the reconstruction of platinum-rhodium alloys
Financed by the Research Council of Norway.
Sintef (project leader)
Yara International ASA
K. A. Rasmussen AS