Abstract: Disclosed is a method for urea finishing. A urea solution is subjected to crystallization and, other than in conventional processes, the urea crystals are shaped by exerting mechanical force onto them. Thus, the conventional prilling or granulation finishing steps can be avoided, and so are the corresponding emissions of ammonia and/or dust. The crystallization comprises a flash crystallization. The invention also pertains to the urea particles obtainable by the process, to a urea plant, and to a method of modifying an existing urea plant.

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: Disclosed is a plant for the production of urea. The plant comprises conventional sections for synthesis and recovery, for evaporation and condensation, for urea finishing, and for dust scrubbing. According to the invention, an additional evaporation and condensation loop is introduced from and to the dust scrubbing section. This loop results in a more favorable energy consumption of the plant.

Abstract: Disclosed is a urea plant comprising an additional reactor. With reference to the regular components of a urea plant, including a recovery section and a high pressure carbamate condenser, the additional reactor is positioned between the recovery section and the high pressure carbamate condenser. The invention also relates to a process for the synthesis of urea, comprising an additional reaction step converting, at an earlier stage than conventional, recovered carbamate into urea.

Abstract: A method and device for evaporating a predeterminable volume of fluid includes successive addition of partial volumes of the predeterminable volume to a supply line at different adding rates, at least partially evaporating the partial volumes forming vapor film between them and a supply line wall, conveying the partial volumes through the supply line to an evaporator surface, and applying the partial volumes to an evaporator surface region varying as a function of mass and/or volume adding rate of the partial volume, permitting effective evaporation of fluid, particularly urea/water solution. Utilization of the highest possible proportion of evaporator surfaces is achieved by mass and/or volume addition rate-dependent distribution of impingement surfaces on the evaporator surface. This heating strategy in the supply line region ensures the Leidenfrost effect when individual partial volumes are added.

Abstract: A process for the manufacture of a flowable granulate by means of spray granulation, which comprises using as starting material a formulation in liquid form comprising (a) a substance or a mixture of substances that is in the form of a waxy or cohesive solid at room temperature, and (b) up to 20% by weight, based on the amount of component (a), of a substance having a specific surface >3 m2/g that is insoluble in component (a), yields granulates that have a narrow particle size distribution and a low dust content and that are stable to storage.

Abstract: A hydrolysis reactor for removal of urea, ammonia and carbon dioxide from a liquid phase comprising urea in aqueous solution advantageously comprises a dividing baffle extending horizontally at a preset height in the reactor in which it defines a first and a second respectively lower and upper reaction space, means of collection and extraction from the reactor of a first portion of a gaseous phase comprising high pressure and temperature steam, previously fed into the first reaction space and means for feeding a second portion of the gaseous phase comprising high pressure and temperature steam to the second reaction space.

Abstract: In a process for urea production, substantially pure ammonia and carbon dioxide are reacted in a main reaction space from which outgoes a reaction mixture subjected to stripping to obtain a partially purified mixture sent to a urea recovery section. From this section, a dilute carbamate solution is obtained which is recycled to an auxiliary reaction space in which the residual carbamate is converted into urea. This process achieves high average conversion yield with reduced energy consumption.