2022年10月12日 · Flow simulations of ammonia oxidation on Pt-gauzes applying mechanistic kinetics. First observation of local variation in N 2 O selectivity across gauze. Upstream wires influence downstream N 2 O selectivity due to flow-guiding effect. Results explain how gauze geometry influences N 2 O selectivity.

Catalytic oxidation of ammonia (NH 3) to nitric oxide (NO), the first step in the Ostwald process for industrial nitric acid (HNO 3) production, uses woven or knitted Pt-alloy gauzes due to their excellent yield and selectivity to NO.

2017年2月1日 · Pt-Rh-Pd alloy group gauzes were installed in dual pressure ammonia oxidation apparatus with the diameter of 3880 mm, which was operated under a pressure of 0.35 MPa. Based on the characterization by FESEM and EDS, the catalysis mechanism of the gauze catalysts was proposed.

2019年1月31日 · In this work, we elucidate the dependency of ammonia oxidation rates and selectivities on both Pt structure and temperature. We perform density functional theory (DFT) computations to compare the reaction and activation energies of elementary reactions on …

2024年1月3日 · observed locally (∼2 μm resolution) for typical Pt/Rh gauze catalysts aged under industrial NH 3 oxidation conditions for 24 to100 h in abench-scale reactor31 and up 50 days pilot plant. This quantitative study of local compositional changes can specify the extent of Pt loss and Rh segregation leading to a redistribution of metals with ...

In the industrial production of nitric acid by the oxidation of ammonia over rhodium-platinum gauze catalysts the infrequent occurrence of an inactive gauze has prompted a number of investigations into their behaviour.

2020年2月29日 · Herein, (100)-terminated Pt-M nanocubes (M = 3d-transition metals Fe, Co, Ni, Zn) are synthesized via wet-chemistry method and their catalytic activities toward AOR are evaluated. The addition of Fe, Co, Ni and Zn elements can enhance the AOR activity due to decrease in oxophilicity of platinum and bifunctional mechanism.

1996年5月1日 · To understand the “pressure and material gap” in the platinum-catalyzed ammonia oxidation over Pt, the reaction was studied over a wide range of pressures (10 −3 – 10 5 Pa) and temperatures (293–1073 K) with different Pt catalysts: stepped Pt (533) single crystal, knitted Pt gauze, and Pt foil.

2016年2月1日 · Modelling of catalytic ammonia oxidation reactor for nitric oxide production in nitric acid plant over gauzes of Pt/Rh catalyst was the subject of current study. Viscosity, mass transfer and kinetic equations were used for the gas mixture feeding the reactor, partial pressure and mole fraction of ammonia was essential, also wire diameter was ...

2018年5月23日 · In the nitric acid industry, platinum loss is the second largest cost due to vaporization of the Pt gauze catalyst at high temperature. In this research, Pt is loaded on TiO 2, ZrO 2, CeO 2, and ceria–zirconia solid solution by photoreduction and used as catalysts for ammonia oxidation.