Abstract: Tube-bundle equipment for heat exchange operations at high pressures and temperatures, under conditions of high aggressiveness of the process fluids, comprising a titanium lining (11) and a series of tubes (1) consisting of at least one layer of zirconium (2), positioned in contact with said fluids, wherein the tube plate on which said tubes are inserted comprises an outer layer (S) of zirconium or an alloy thereof and an underlying layer (5) of titanium welded to the lining of the equipment. Said equipment is particularly used as a heat exchanger, for example as a stripper, in the high-pressure cycle of urea syntheses processes.

Abstract: Tube-bundle equipment for heat exchange operations at high pressures and temperatures, under conditions of high aggressiveness of the process fluids, comprising a titanium lining (11) and a series of tubes (1) consisting of at least one layer of zirconium (2), positioned in contact with said fluids, wherein the tube plate on which said tubes are inserted comprises an outer layer (S) of zirconium or an alloy thereof and an underlying layer (5) of titanium welded to the lining of the equipment. Said equipment is particularly used as a heat exchanger, for example as a stripper, in the high-pressure cycle of urea syntheses processes.

Abstract: Tube-bundle equipment of the falling liquid film type, comprising a vertical cylindrical body closed at the ends and divided into at least an upper section, an intermediate section and a lower section by means of two perforated tube sheets arranged transversally to support the tubes forming the bundle, wherein each of said tubes is surmounted, on the upper end, by a ferrule, for the inlet and distribution of the liquid in the form of a film, which comprises in the upper part, one or more openings for the outlet of vapours, at an intermediate height one or more openings, preferably tangential, for the inlet of the liquid and below, a circular base for resting on said tube from which an internal cylindrical section, inserted in the tube for a length varying from 10 to 200 mm, protrudes downwards together with an outer metallic strip for a length of at least 2 mm, so that, in the circular area defined between said outer metallic strip and said protruding cylindrical section, there is a gasket, inserted between s

Abstract: An enhanced process is described for the synthesis of urea from ammonia and carbon dioxide, at a high pressure and temperature, with the formation of ammonium carbamate as intermediate, which includes a high pressure synthesis section, comprising at least one separation step by decomposition-stripping with ammonia of the non-converted ammonium carbamate, carried out in a vertical apparatus, commonly called stripper, characterized in that said step also comprises a feeding, in the lower part of said stripper, of a stream of CO2, heated to a temperature ranging from 130 to 230° C., in a quantity of 1 to 15% by weight with respect to the total weight of the fresh CO2 fed to the process, containing a passivating agent in such a quantity that its equivalent content of O2 in moles varies from 0.05% to 0.80% with respect to the moles of CO2 of said stream.

Abstract: An enhanced process is described for the synthesis of urea from ammonia and carbon dioxide, at a high pressure and temperature, with the formation of ammonium carbamate as intermediate, which includes a high pressure synthesis section, comprising at least one separation step by decomposition-stripping with ammonia of the non-converted ammonium carbamate, carried out in a vertical apparatus, commonly called stripper, characterized in that said step also comprises a feeding, in the lower part of said stripper, of a stream of CO2, heated to a temperature ranging from 130 to 230° C., in a quantity of 1 to 15% by weight with respect to the total weight of the fresh CO2 fed to the process, containing a passivating agent in such a quantity that its equivalent content of O2 in moles varies from 0.05% to 0.80% with respect to the moles of CO2 of said stream.