Abstract: A method for the removal of nitrogen oxides contained in combustion flue gas through treatment with gaseous ammonia, in which the gaseous ammonia is generated in situ by hydrolysis reaction of an aqueous urea solution (L4) whereby the ammonia generated by the) hydrolysis (L5) is accumulated in gaseous state, under pressure, in an accumulator (A5).

Abstract: A process for effecting mass transfer between a liquid phase and a gaseous phase in a filled-type column comprising an external shell which accommodates at least one filler-containing basket wherethrough the phases are caused to flow in countercurrent relationship, advantageously comprises the step of feeding the gaseous phase to the at least one basket through a gas-permeable surface thereof which is larger than the basket cross-section, preferably in a prevailing radial flow direction.

Abstract: A method for carrying out chemical reactions in so-called pseudo-isothermal conditions and in a predetermined reaction environment, for example a catalytic bed, comprises the step of arranging in the reaction environment at least one heat exchanger crossed by an operating fluid along a main direction.

Abstract: A pseudo-isothermal chemical reactor comprises a plurality of boxed, plate-shaped heat exchangers with a substantially flattened rectangular shape, formed from a pair of juxtaposed metallic plates, spaced apart and joined perimetrically, defining an inner chamber intended to be crossed by a heat exchange operating fluid. Spacer elements are located between said metallic plates. The reactor may be used for high pressure urea production.

Abstract: Pseudo-isothermal chemical reactor (1) for catalytic reactions with a vertical axis, comprising a substantially cylindrical shell (2), Closed at the opposite ends by upper (4) and lower (3) bottoms respectively, a reaction zone (8) in which a catalytic bed (11) and a plurality of flat, boxed, plate-shaped heat exchangers (12), having the shape of a parallelepiped and having long sides parallel to said vertical axis and short sides perpendicular to it, situated in said reaction zone and supported in an arrangement on parallel cords at a predetermined distance.

Abstract: In a process for urea production of the type comprising the reaction between ammonia and carbon dioxide in a high-pressure reactor followed by an autothermal stripping of the resulting reaction mixture so as to obtain a gaseous flow comprising ammonia and carbon dioxide and a liquid flow comprising urea and residual carbamate in aqueous solution and by a stripping of said gaseous flow in units operating at medium pressure, a gaseous flow coming from said units operating at medium pressure and comprising ammonia and carbon dioxide is partially condensed in a condenser to give a mixed liquid/gaseous flow. The uncondensed gases comprising ammonia and carbon dioxide are separated from the liquid phase in a separator and subjected to washing in a packed portion of a column in countercurrent with a flow of a carbonate solution obtaining a gaseous flow essentially consisting of ammonia and a liquid flow comprising a carbamate solution in which the carbon dioxide contained in said uncondensed gases has been absorbed.

Abstract: Heat exchange unit of the so-called multiservice type comprising a substantially cylindrical shell closed at the opposite ends by respective base plates, a plurality of heat exchangers supported inside this shell and in fluid communication with the outside thereof.

Abstract: Method for carrying out in continuous, under so-called pseudo-isothermal conditions and in a predetermined reaction environment, such as a catalytic bed, a selected chemical reaction, comprising the steps of providing in the reaction environment at least one tubular heat exchanger fed with a first flow of a heat exchange operating fluid at a respective predetermined inlet temperature, the fluid passing through the at least one tubular heat exchanger according to a respective inlet/outlet path, which method also provides the step of feeding into the at least one tubular heat exchanger and at one or more intermediate positions of said path, a second flow of operating fluid having a respective predetermined inlet temperature.

Abstract: A nozzle for distributor devices of granule's growth liquid substance in fluid bed granulators, is distinguished by the fact that it comprises a first duct (2), with substantially rectilinear axis (A) and with a predetermined diameter, which duct has an end portion (3) including a supply opening (4) and made of at least two subsequent segments, a first cone-shaped segment (5) converging on the axis (A) and a further cone-shaped segment (7) diverging from the axis (A) and ending in the supply opening (4), a second duct (8) extending co-axially inside the first duct (2), with which it forms an annular space (9), the second duct (8) having a supply end (10) extended inside the first cone-shaped segment (5) of the first duct (2).

Abstract: In an integrated process for urea and melamine production, urea is produced in a urea plant (12) comprising a high pressure urea synthesis section (15) and a urea recovery section (16) for separating urea from a carbamate aqueous solution, and melamine is produced in a melamine plant (11) wherein off-gases resulting as byproducts of the melamine synthesis are discharged therefrom at a pressure of at least 2 bar and recycled to the high pressure urea synthesis section (15).

Abstract: A process for obtaining finished granules of a predetermined substance in a granulation fluid bed (F1) of the so-called vertical growth type, the bed being formed and maintained by a respective flow of fluidification air, comprises a transfer phase by falling of the finished granules in a pressurized space below the granulation bed and a recovery phase of the finished granules from the pressurized space.

Abstract: Process for cooling and crystallizing solid melamine from the gaseous phase or from melamine melts as they develop in technical processes used to produce melamine, characterized in that the melamine-containing process gases or melamine melts are introduced into a liquid, organic phase at high pressure, said phase comprising polyvalent alcohols such as ethylene glycol, glycerine or their homologous series or of amines such as ethanol amines. Mixtures of both groups of compounds are suitable as well. The advantage of this process is that the hot melamine is cooled very quickly without forming thermal decomposition products and that during quenching no reaction of the melamine with the solvent occurs as in the case with a water quench.

Abstract: Fluid bed granulation process comprising the step of cooling the granules in a cooling fluid bed (F2). At least part of the fluidizing air coming out from said cooling fluid bed (F2) is fed into the granulation fluid bed (F1).

Abstract: A process for the separation and recovery of carbon dioxide from waste gases produced by combustible oxidation is described comprising the steps of feeding a flow of waste gas to a gas semipermeable material, separating a gaseous flow comprising high concentrated carbon dioxide from said flow of waste gas through the gas semipermeable material, and employing at least a portion of the gaseous flow comprising high concentrated carbon dioxide as feed raw material in an industrial production plant and/or stockpiling at least a portion of the gaseous flow comprising carbon dioxide.

Abstract: Apparatus for the granulation of a predetermined substance provided in fluid, semi-fluid and similar state, comprising a prilling tower.

Abstract: Process for cooling and crystallizing solid melamine from the gaseous phase or from melamine melts as they develop in technical processes used to produce melamine, characterized in that the melamine-containing process gases or melamine melts are introduced into liquid, organic phase at high pressure, said phase comprising polyvalent alcohols such as ethylene glycol, glycerine or their homologous series or of amines such as ethanol amines or a mixture of both groups. The advantage this process is that the hot melamine is cooled very quickly without forming thermal decomposition products and that during quenching no reaction of the melamine with the solvent occurs, the formation of higher deammoniation products such as melam and melem is prevented and higher deammoniation products of the melamine such as melam and melem, are partially converted back into melamine.

Abstract: A method for formaldehyde production through catalytic oxidation of methanol, comprising the steps of feeding to a first oxidation catalytic bed (2) a gas flow comprising methanol and oxygen at a predetermined crossing linear flow rate, obtaining at the outlet of said first catalytic bed (2) a flow of gaseous reaction products comprising unreacted methanol, and feeding the flow of gaseous products to a second oxidation catalytic bed (6) is distinguished by the fact that the flow of gaseous reaction products comprising unreacted methanol is fed to the second catalytic bed (6) with a crossing linear flow rate substantially equal to said predetermined first catalytic bed (2) feeding flow rate.

Abstract: Pseudo-isothermal chemical reactor for heterogeneous chemical reactions comprising a substantially cylindrical shell closed at the opposite ends by respective bottoms, upper and lower, a reaction zone containing at least one catalytic bed and at least one tubular heat exchanger, intended to be crossed, along a predetermined direction, by an operating heat exchange fluid and embedded in said catalytic bed.

Abstract: In a process for urea production of the type comprising the reaction between ammonia and carbon dioxide in a high-pressure reactor followed by an autothermal stripping of the resulting reaction mixture so as to obtain a gaseous flow comprising ammonia and carbon dioxide and a liquid flow comprising urea and residual carbamate in aqueous solution and by a stripping of said gaseous flow in units operating at medium pressure, a gaseous flow coming from said units operating at medium pressure and comprising ammonia and carbon dioxide is partially condensed in a condenser to give a mixed liquid/gaseous flow. The uncondensed gases comprising ammonia and carbon dioxide are separated from the liquid phase in a separator and subjected to washing in a packed portion of a column in countercurrent with a flow of a carbonate solution obtaining a gaseous flow essentially consisting of ammonia and a liquid flow comprising a carbamate solution in which the carbon dioxide contained in said uncondensed gases has been absorbed.

Abstract: Catalysts for ammonia synthesis based on ruthenium, directly supported over graphite having BET specific surface area in excess of 10 m2/g, preferably in excess of 100 m2/g and more preferably in excess of 280 m2/g, the graphite being characterised by X-ray diffraction pattern containing the diffraction lines characteristic of the crystalline graphite only, with exclusion of relevant bands due to amorphous carbon, to which catalysts barium, caesium and potassium are added as promoters. The graphitic supports allow to avoid the known pre-treatments and post-treatments needed in the case of supports obtained by partial graphitisation of active carbons and during use they are affected negligibly by the methanation shown by the supports obtained from active carbons. Furthermore, the catalysts of the present invention are characterised by a very high activity, even with ruthenium loadings well below the known loading.