Abstract: A process for synthesis of urea and a related reaction section of a urea plant, where: ammonia and carbon dioxide are reacted in a liquid phase in a first reaction zone (S1) and heat (Q1) is withdrawn from said first reaction zone to promote the formation of ammonium carbamate, the liquid product (103) from said first reaction zone is then passed to a second reaction zone (S2) distinguished from said first reaction zone, and heat (Q2) is added to said second reaction zone to promote the decomposition of ammonium carbamate into urea and water, where the liquid phase in at least one of said first reaction zone and second reaction zone is kept in a stirred condition. A downflow reactor for carrying out the above process is also disclosed.

Abstract: A fluid bed granulation process of a predetermined substance comprises the steps of: forming, through a fluidification. air flow of predetermined flow rate, a fluid bed of granules of said substance to be granulated fed to it in the form of seeds,—feeding said fluid bed with a continuous flow of a growth substance (or liquid).

Abstract: A fluid bed granulation process and apparatus, wherein a suitable fluid bed of a particulate material is maintained in a granulator (1) fed by an input flow (F) comprising a growth liquid (L) and by a flow (S1) of seeds adapted to promote the granulation, and wherein a part (F2) of said input flow (F) is taken upstream the feeding of the fluid bed, and used in a seeds generator (33), to produce the seeds for the fluid bed.

Abstract: A process for high-pressure, liquid phase conversion of urea into melamine is disclosed, where molten urea is fed to a first reaction zone (S1) where the melamine melt is under mechanical agitation, and a heat input (Q1) is provided to maintain the endothermic reaction, and the liquid is then passed to a second reaction zone (S2) kept at a lower temperature and where further agitation is provided. Embodiments of plants adapted to carry out the process are also disclosed, including multiple stirred reactors in cascade and a single reactor with multiple internal compartments defining said first and second reaction zones.

Abstract: A process for the production of granules or pellets containing filamentous fungi is described comprising the steps of selecting and growing filamentous fungi in a suitable culture medium for a predetermined amount of time, adding a gelling agent and at least one carrier to said culture medium, so as to obtain a mixture, subjecting said mixture to gelling through contact, drop by drop, with a solution containing a calcium salt thus obtaining gelled pellets or granules containing said filamentous fungi and drying said gelled pellets or granules to a moisture content of 13-18%.

Abstract: Plant for urea production from ammonia and carbon dioxide having a so-called high-pressure section which comprises a synthesis reactor and a condensation unit (7, 107) positioned inside the reactor, all substantially operating at the same pressure.

Abstract: A process for ammonia -urea production where: liquid ammonia produced in an ammonia section is fed to a urea section directly at the ammonia synthesis pressure, and where the liquid ammonia is purified at high pressure with the steps of: cooling the liquid ammonia (20) obtaining a cooled liquid ammonia stream (21), separating a gaseous fraction (22) comprising hydrogen and nitrogen from said cooled liquid ammonia, obtaining purified liquid ammonia (23) at a high pressure, and reheating said purified liquid ammonia (23) after separation of said gaseous fraction, obtaining a reheated purified ammonia (24) having a temperature suitable for feeding to the urea synthesis process. The application also deals with an ammonia -urea plant comprising an ammonia cooler, a liquid-gas separator and an ammonia re-heater and with a method for revamping existing ammonia -urea plants.

Abstract: A process for preparation of a granular urea product by granulating a urea solution in a fluidized bed, where the granulation process takes place along a substantially longitudinal growth path, from a granulation starting end (1s) to a product discharge end (1E) of said fluidized bed, and said urea solution enters the fluidized bed by means of several urea inputs (2A, 2B, 2C) taken from a main urea feed (2), where an additive (6) is mixed with said urea solution said additive has a non-uniform concentration in said urea inputs, so that at least two of said urea inputs have a different concentration of additive.

Abstract: A process for urea production from ammonia and carbon dioxide, made to react at a predetermined high pressure in an appropriate synthesis reactor (112), from the reaction between NH3 and CO2 being obtained a reaction mixture comprising urea, ammonium carbamate and free ammonia in aqueous solution, from which a recovery of ammonium carbamate and ammonia is carried out with their subsequent recycle to the synthesis reactor (112), said recovery from the reaction mixture taking place through operative steps of decomposition of the ammonium carbamate into NH3 and CO2 and of their stripping and a subsequent operative step of their recondensation into ammonium carbamate that is recycled to the synthesis reactor, the said reaction mixture obtained from the reaction between ammonia and carbon dioxide being pumped to the operative steps of decomposition and stripping.

Abstract: A process for producing urea is disclosed, wherein liquid ammonia and carbon dioxide are reacted in a high-pressure synthesis section (100), and at least part of the carbon dioxide is fed to said synthesis section (100) in liquid phase. A plant operating according to said process and a method for modernizing existing plants accordingly are also disclosed.

Abstract: The present invention concerns process for obtaining melamine at high purity characterized by comprising the steps of:—quenching a melamine melt, deprived of off-gases of the melamine synthesis and containing melamine impurities such as ammeline, ammelide and polycondensates, with an aqueous solution comprising ammonia under conditions such to substantially convert polycondensates into melamine, obtaining a melamine solution substantially free of polycondensates, recovering melamine from said melamine solution by melamine crystallisation, obtaining melamine crystals and a melamine crystallization mother liquor,—treating said crystallization melamine mother liquor under conditions such to convert at least a portion of its ammeline content into ammelide and melammine, obtaining a treated mother liquid having at least a reduced ammeline content.

Abstract: A stripper (SN) for carbamate decomposition and ammonia plus carbon dioxide recovery from a urea solution (U) is realized with a shell-and-tube heat exchanger, where a liquid falling film of urea solution and a counter-current gaseous flow of a stripping medium fed to a bundle of surface-heated tubes (6); the stripping medium such as carbon dioxide is distributed into the tubes (6) by a plurality of gas risers (32); the gas risers are preferably associated to a perforated tray (30) in the bottom chamber (11) of the stripper. Revamping of a conventional CO2 stripper is also disclosed.

Abstract: A process for producing urea is disclosed, wherein liquid ammonia and carbon dioxide are reacted in a high-pressure synthesis section (100), and at least part of the carbon dioxide is fed to said synthesis section (100) in liquid phase. A plant operating according to said process and a method for modernizing existing plants accordingly are also disclosed.

Abstract: A granulation process wherein a liquid is sprayed into a prilling tower (1) by means of a rotating prilling bucket (15) having a perforated side wall (15a), and the liquid jets exiting said perforated side wall are subjected to a vibrating action according to the axial direction (A-A) of the prilling tower (1), while the remaining liquid mass inside the bucket is kept substantially free from said vibrating action. A suitable apparatus is also disclosed, wherein the peripheral side wall (15a) of the prilling bucket (15) is connected to vibration imparting means and has a flexible connection with the frame (15b, 15c) of the bucket.

Abstract: A method for revamping a conventional self-stripping urea plant is disclosed, where a minor portion (18a) of the carbon dioxide feed is fed to the stripper (7) and used as a stripping agent. In further embodiments, another carbamate condenser is installed, or the conventional horizontal shell-and-tube carbamate condenser (6) is replaced with a vertical submerged unit.

Abstract: A process and a related plant layout for producing urea are disclosed, wherein the high-pressure loop (1) comprises a synthesis reactor (2), a thermal stripper (3), a condenser (4), and an adiabatic CO2 stripper (10) disposed upstream said thermal stripper, separating a vapour phase (13) containing ammonia from the urea solution (9) discharged from the reactor, and recycling said vapour phase to the reactor. The adiabatic stripper (10) can be incorporated in a reactor (200) having a top reaction zone and a bottom adiabatic stripping zone. A revamping method for a conventional urea plant in accordance with the inventive process is also disclosed.

Abstract: In a method for preparing granules containing filamentary fungi, a filamentary fungi culture is mixed with at least one modified starch and a starchy flour, then fillers and possible nutrients are added to the obtained product, obtaining a paste that is subsequently subjected to granulation and drying.

Abstract: A process and a related plant layout for producing urea are disclosed, wherein the high-pressure loop (1) comprises a synthesis reactor (2), a thermal stripper (3), a condenser (4), and an adiabatic CO2 stripper (10) disposed upstream said thermal stripper, separating a vapour phase (13) containing ammonia from the urea solution (9) discharged from the reactor, and recycling said vapour phase to the reactor. The adiabatic stripper (10) can be incorporated in a reactor (200) having a top reaction zone and a bottom diabatic stripping zone. A revamping method for a conventional urea plant in accordance with the inventive process is also disclosed.

Abstract: A method for atomizing a liquid (L) in a spraying nozzle (1), wherein a gaseous phase (G) and said liquid (L) are fed to a mixing chamber (30) inside said nozzle (1), obtaining an emulsion of the gas in the liquid, the emulsion being under pressure inside said chamber and formed by gas bubbles enveloped by the liquid in a film state; the speed of the gaseous phase at the inlet of the mixing chamber is around the speed of sound or greater, and the atomized liquid is obtained by an expansion of said emulsion at the outlet of said chamber. A suitable nozzle (1) is also disclosed, comprising a mixing chamber (30) and a distribution device (D) adapted to provide appropriate gas and liquid feed to form said emulsion.

Abstract: A process for urea production from ammonia and carbon dioxide, in which part of the aqueous solution comprising urea, ammonium carbamate and ammonia obtained in a urea synthesis section is subjected to dissociation in a treatment section operating at a predetermined medium pressure for the recovery of the ammonium carbamate and of the ammonia contained in it, comprises the steps of subjecting the urea aqueous solution resulting from the aforementioned dissociation step to decomposition in a low pressure urea recovery section and of using at least a part of the condensed steam, obtained by indirect thermal exchange with a second part of said aqueous solution comprising urea, ammonium carbmate and ammonia in a high-pressure stripping unit, as a heating fluid for the dissociation of the first part of the aqueous solution comprising urea, ammonium carbmate and ammonia in the medium-pressure treatment section.