Abstract: A process for producing nitric acid comprising: catalytic oxidation of ammonia in the presence of oxygen to form a nitrous gas containing NO, O2, N2O and water vapor; a catalytic abatement of N2O which is performed over a first catalyst; a catalytic conversion of NO into NO2 which is performed over a second catalyst; the so obtained nitrous gas is then subject to absorption in water to produce nitric acid.

Abstract: The present invention relates to a reaction device with air-lift type internal circulation which includes: a vertical cylindrical volume (1), more than one draft tube vertical element (2) positioned within the cylindrical volume (1) in such a manner as to form an gap with the walls of said volume, more than one gas distributor (3), each of which is positioned on the bottom of said device; wherein: each vertical internal element (2) has an internal diameter which increases along the vertical axis of said element, and the ratio between the total height of the reaction device and the internal diameter of the reaction device is less than 1.

Abstract: The present invention relates to a reaction device with air-lift type internal circulation which includes:—a vertical cylindrical volume;—a vertical element positioned within said volume in such a way as to form an interspace with the walls of said volume, having a cross-section which is circular and orthogonal to the vertical axis of the element and with a variable internal diameter along said axis, said element being denoted “draft tube”;—at least one gas distributor positioned on the bottom of said device; said device being characterised in that:—the ratio between the diameter of the internal vertical element and the internal diameter of the cylindrical volume ranges from 0.05 to 0.5, and—the ratio between the height of the vertical element and the height of the cylindrical volume is less than 0.5.

Abstract: The present invention relates to a reaction device with air-lift type internal circulation which includes: a vertical cylindrical volume (1), more than one draft tube vertical element (2) positioned within the cylindrical volume (1) in such a manner as to form an gap with the walls of said volume, more than one gas distributor (3), each of which is positioned on the bottom of said device; wherein: each vertical internal element (2) has an internal diameter which increases along the vertical axis of said element, and the ratio between the total height of the reaction device and the internal diameter of the reaction device is less than 1.