摘要:
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 CO 2 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.
摘要:
A process and a plant for the preparation of an acqueous solution of urea suitable for use in a SCR process for nitrogen oxides removal, wherein the urea solution from the recovery section of a urea plant is subject to at least one step of evaporation, separating a vapour stream containing water and ammonia, and obtaining a concentrated and substantially ammonia-free solution, and said concentrated solution is diluted to the concentration of urea suitable for use in the SCR process.
摘要:
In an integrated process for urea and melamine production, urea is produced in a urea plant (10) comprising a high pressure urea synthesis section (11) from which an aqueous solution comprising urea, ammonium carbamate and ammonia is obtained and a urea recovery section (21) operating at low pressure, and melamine is produced in a melamine plant (40) wherein off-gases resulting as by-products of the melamine synthesis are discharged from said plant at a medium pressure and recycled to the high-pressure urea synthesis section (11).
摘要:
A carbamate condensation unit (1) of the submerged type for synthesis urea production plants comprising a tube bundle (5) for the condensation of gaseous compounds, is distinguished in that it further comprises a duct (19,23) structurally independent from the tube bundle (5), for the circulation of part of the condensed gaseous compounds inside the condensation unit (1).
摘要:
A method for the modernisation of a plant for urea production of the type comprising a reactor (2) for urea synthesis, a stripping unit (3) with carbon dioxide and at least one vertical condensation unit (4) of the film type, foresees the provision of means (36) for feeding a major portion of a flow comprising ammonia and carbon dioxide in vapour phase leaving the stripping unit (3) to the condensation unit (4) and the provision in said condensation unit (4) of means (37) for subjecting to substantially total condensation such major portion of the flow comprising ammonia and carbon dioxide in vapour phase, obtaining a flow comprising urea and carbamate in aqueous solution, then fed to the reactor (2) for urea synthesis. Thanks to the present method of modernisation, the efficiency of the condensation unit (4) is remarkably improved, thus permitting an increase of its capacity.
摘要:
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.
摘要:
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.