Institut Francais Du Pe'trole

Thierry Becue

Gil Mabilon

Etienne Lebas

Karin Marchand

Arnold Lambert

Philippe Villeret

Karine Malefant

The invention concerns materials for eliminating oxides of nitrogen NO and NO present in exhaust gases, in particular from the internal combustion engines of automotive vehicles operating in a medium that is super-stoichiometric in oxidizing agents, which can adsorb oxides of nitrogen then desorb the oxides of nitrogen by elevating the temperature with respect to the adsorption temperature or by passage of a rich mixture, the materials comprising mixed oxides the metals of which are in octahedral co-ordination, with the octahedra connecting together so that the structure generates micropores in the form of channels. The channel width of the materials is such that the sides are composed of 2 and/or 3 octahedra. These materials adsorb oxides of nitrogen by insertion and do not become poisoned in contact with oxides of sulfur and carbon contained in the gases. In the presence of a group VIII metal or another suitable element such as iron, zinc or aluminum, these materials are capable of eliminating oxides of nitrogen adsorbed by reduction during passage of a rich mixture.

Material with a channel structure for eliminating oxides of nitrogen

The invention relates to materials for removing the nitrogen oxides NO and NO present in exhaust gases, particularly from internal combustion engines of automotive vehicles running in a medium containing a superstoichiometric proportion of oxidizing agents, said materials being capable of absorbing the nitrogen oxides and of desorbing the nitrogen oxides when the temperature is raised, relative to the absorption temperature, or when the gas composition is changed to a rich mixture, said materials being mixed oxides in which the metals A and B are all octahedrally coordinated and are arranged to form the ilmenite structure ABO . These materials absorb the nitrogen oxides and do not become poisoned in contact with the sulfur oxides and carbon oxides containing in the gases. In the presence of a group VIII metal, the material is capable of eliminating the adsorbed nitrogen oxides by reduction when the gas composition is changed to a rich mixture.

Method of removing nitrogen oxides using an ilmenite material

The invention concerns materials for eliminating oxides of nitrogen NO and NO present in exhaust gases, in particular from the internal combustion engines of automotive vehicles operating in a medium which is super-stoichiometric in oxidising agents, which can adsorb oxides of nitrogen then desorb the oxides of nitrogen by elevating the temperature with respect to the adsorption temperature or by passage of rich mixture, said materials comprising mixed oxides the metals of which are in octahedral coordination, with the octahedra connecting together so that the structure generates micropores in the form of channels. These materials adsorb oxides of nitrogen by insertion and do not become poisoned in contact with oxides of sulphur and carbon contained in the gases. In the presence of a group VIII metal, these materials are capable of eliminating oxides of nitrogen absorded by reduction during passage of a rich mixture.

Process for eliminating oxides of nitrogen

Process for adsorbing and desording oxides of nitrogen

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Paris, France

Thierry Becue