Abstract: A process for synthesis of urea from ammonia and carbon dioxide comprising the synthesis of urea in parallel in a first urea reactor (1) at a first urea synthesis pressure and in a second urea reactor (2) at a second and lower urea synthesis pressure; a stripping step of the reaction effluent of the first reactor, which is performed in a stripper (4) operating at a stripping pressure lower than the first urea synthesis pressure; the reaction effluent (21) of the second reactor (2) and the stripper liquid effluent (11) are sent to a recovery section (13) where a carbamate-containing recycle solution (17) is produced, and said recycle solution (17) is sent partly to said first reactor and partly to said second reactor.

Abstract: A process for synthesis of urea from ammonia and carbon dioxide wherein: the urea synthesis is performed with a stripping process in a synthesis loop including at least a reactor (1), a stripper (2) and a condenser (3); the reactor effluent is treated in the stripper to remove unreacted ammonia and carbon dioxide; the urea solution (14) from the stripper is sent to a low-pressure recovery section (4); the stripper vapours are split into a first portion (151) directed to the reactor and a second portion (152) sent to the condenser; the condenser (3) is a shell-and-tube kettle condenser where condensation of stripper vapours is performed in the tube side (30); a carbamate-containing effluent (20) from the condenser is returned to the reactor.

Abstract: A process for purifying a urea-containing aqueous stream, such as the aqueous stream from the recovery section of a urea plant, comprising a step of removing biuret from the urea-containing stream by reverse osmosis in one or more reverse osmosis stages.

Abstract: A method for measuring a liquid level (L) in a pressure vessel (2) the method comprising: providing a thermometric well (10) inside the pressure vessel, heating an inner surface of the thermometric well which is not in contact with the fluid, detecting the temperature of at least one detection point of said inner surface; estimating a position of the liquid level based on the difference between a reference temperature and the temperature so detected.

Abstract: A process for synthesis of urea from ammonia and carbon dioxide comprising the synthesis of urea in parallel in a first urea reactor (1) at a first urea synthesis pressure and in a second urea reactor (2) at a second and lower urea synthesis pressure; a stripping step of the reaction effluent of the first reactor, which is performed in a stripper (4) operating at a stripping pressure lower than the first urea synthesis pressure; the reaction effluent (21) of the second reactor (2) and the stripper liquid effluent (11) are sent to a recovery section (13) where a carbamate-containing recycle solution (17) is produced, and said recycle solution (17) is sent partly to said first reactor and partly to said second reactor.

Abstract: Plant for the synthesis of urea comprising: a synthesis section (101), wherein ammonia (1) and carbon dioxide (2) react to give an aqueous solution (3) containing urea and ammonium carbamate; at least one recovery section fed with said depressurized aqueous solution and in a two-phase state, said recovery section comprising a separator (104,108) which processes said two-phase solution; a pre-decomposer (105, 109), a decomposer (106, 110) and a condenser (107, 111), wherein the gaseous streams obtained in the separator and in the decomposer are condensed in said condenser of the recovery section.

Abstract: Plant for the synthesis of urea comprising: a synthesis section (101), wherein ammonia (1) and carbon dioxide (2) react to give an aqueous solution (3) containing urea and ammonium carbamate; at least one recovery section fed with said depressurized aqueous solution and in a two-phase state, said recovery section comprising a separator (104,108) which processes said two-phase solution; a pre-decomposer (105, 109), a decomposer (106, 110) and a condenser (107, 111), wherein the gaseous streams obtained in the separator and in the decomposer are condensed in said condenser of the recovery section.

Abstract: A process for the finishing of urea comprising: (a) removing water from an aqueous urea solution in a first evaporation and condensation section, obtaining a urea melt; (b) subjecting said urea melt to a finishing treatment comprising granulation and resulting in solid urea and air contaminated with urea dust and ammonia; (c) subjecting said contaminated air to acid scrubbing, producing an aqueous solution comprising urea and ammonium salts; (d) subjecting at least part of said aqueous solution to evaporation in a second evaporation section, obtaining a liquid stream comprising urea and ammonium salts and a gaseous stream; (e) condensing said gaseous stream in a second condensation section, obtaining a recycle aqueous stream; (f) using at least a part of said recycle aqueous stream for the scrubbing of contaminated air; (g) converting at least a portion of said liquid stream comprising urea and ammonium salts into solid particles, and (h) using said solid particles as seeds for the granulation; a correspondin

Abstract: An integrated process for the synthesis of urea and melamine, wherein: urea is synthesized with a stripping process in a high-pressure synthesis loop comprising a reactor, a stripper and a carbamate condenser, and the urea solution leaving said stripper is sent to a recovery section to produce a concentrated urea product and a recovered carbamate solution; at least part of said urea product is converted to melamine, and the off-gas from the synthesis of melamine are recycled to the urea synthesis by mixing with the gas phase from the stripper and with said recovered carbamate solution, thus forming a mixed flow which is then condensed in said carbamate condenser, and the condensate is eventually directed to the reactor.

Abstract: A process for the finishing of urea comprising: (a) removing water from an aqueous urea solution in a first evaporation and condensation section, obtaining a urea melt; (b) subjecting said urea melt to a finishing treatment comprising granulation and resulting in solid urea and air contaminated with urea dust and ammonia; (c) subjecting said contaminated air to acid scrubbing, producing an aqueous solution comprising urea and ammonium salts; (d) subjecting at least part of said aqueous solution to evaporation in a second evaporation section, obtaining a liquid stream comprising urea and ammonium salts and a gaseous stream; (e) condensing said gaseous stream in a second condensation section, obtaining a recycle aqueous stream; (f) using at least a part of said recycle aqueous stream for the scrubbing of contaminated air; (g) converting at least a portion of said liquid stream comprising urea and ammonium salts into solid particles, and (h) using said solid particles as seeds for the granulation; a correspondin

Abstract: A method for revamping a self-stripping urea plant comprising the installation of a new CO2-stripping synthesis section (6), wherein at least part of the aqueous urea solution (10) leaving said new section (6) is directed to the existing low pressure recovery section (4) of the self-stripping plant, by-passing the existing self-stripping high-pressure section (2) and medium pressure treatment section (3).

Abstract: An integrated process for the synthesis of urea and melamine, wherein: urea is synthesized with a stripping process in a high-pressure synthesis loop comprising a reactor, a stripper and a carbamate condenser, and the urea solution leaving said stripper is sent to a recovery section to produce a concentrated urea product and a recovered carbamate solution; at least part of said urea product is converted to melamine, and the off-gas from the synthesis of melamine are recycled to the urea synthesis by mixing with the gas phase from the stripper and with said recovered carbamate solution, thus forming a mixed flow which is then condensed in said carbamate condenser, and the condensate is eventually directed to the reactor.

Abstract: A method for revamping a self-stripping urea plant comprising the installation of a new CO2-stripping synthesis section (6), wherein at least part of the aqueous urea solution (10) leaving said new section (6) is directed to the existing low pressure recovery section (4) of the self-stripping plant, by-passing the existing self-stripping high-pressure section (2) and medium pressure treatment section (3).

Abstract: Interference fit assembly of a first metal part and a second metal part, wherein the first metal part has a recess with an inner contact surface, and the second metal part has an outer contact surface being coupled to the inner contact surface by an interference fit. At least one of the contact surfaces includes a surface layer including a diamond-like carbon. In a method for producing an interference fit assembly the surface layer is applied on at least one of the contact surfaces by a Physical Vapor Deposition or a Chemical Vapor Deposition process with the surface layer having the diamond-like carbon.

Abstract: A valve assembly (80) of an injection valve (82) has a valve body (4) including a central longitudinal axis (L), the valve body (4) having a cavity (8) forming an inner surface (18) of the valve body (4), the cavity (8) having a fluid inlet portion (42), and a fluid outlet portion (44), a valve needle (10) axially movable in the cavity (8), the valve needle (10) preventing a fluid flow through the fluid outlet portion (44) in a closing position and releasing the fluid flow through the fluid outlet portion (44) in further positions, the valve needle (10) and/or the inner surface (18) of the valve body (4) having a surface layer (48) with a tungsten carbide layer (70) and a carbon layer (72).

Abstract: An injection valve (16) has an actuator module (4) with a cavity (20) and an actuator unit (14). The injection valve (16) further has a fluid module (2), being disposed at least partially within the cavity (20) of the actuator module (4) and a housing and a valve needle (8). The valve needle (8) is disposed in the housing and is actuatable by the actuator unit (14). The valve needle (8) is operable to prevent a fluid injection in a closing position and permit the fluid injection in further. The actuator module (4) is adhered to the fluid module (2) via a metal adhesive (16), which is arranged between a surface of the housing of the fluid module (2) and a surface of a wall of the cavity (20) of the actuator module (4).

Abstract: Interference fit assembly (10) of a first metal part (12) and a second metal part (18), wherein the first metal part (12) has a recess (14) with an inner contact surface (16), and the second metal part (18) has an outer contact surface (20) being coupled to the inner contact surface (16) by an interference fit. At least one of the contact surfaces (16, 20) has a surface layer (22) has a diamond-like carbon layer (24). In a method for producing an interference fit assembly (10) the surface layer (22) is applied on at least one of the contact surfaces (16, 20) by a Physical Vapor Deposition (PVD) or a Chemical Vapor Deposition (CVD) process with the surface layer (22) having the diamond-like carbon layer (24).

Abstract: A valve assembly (80) of an injection valve (82) has a valve body (4) including a central longitudinal axis (L), the valve body (4) having a cavity (8) forming an inner surface (18) of the valve body (4), the cavity (8) having a fluid inlet portion (42), and a fluid outlet portion (44), a valve needle (10) axially movable in the cavity (8), the valve needle (10) preventing a fluid flow through the fluid outlet portion (44) in a closing position and releasing the fluid flow through the fluid outlet portion (44) in further positions, the valve needle (10) and/or the inner surface (18) of the valve body (4) having a surface layer (48) with a tungsten carbide layer (70) and a carbon layer (72).

Abstract: A lever-operated control device (1) for mounting on the handlebar of a motorcycle, snowmobile or the like, said device being arranged to operate a user associated with the vehicle, such as its engine gear shifter, and comprising a body with at least one annular portion (3) to be mounted on the vehicle handlebar (4), the device presenting pusher-type control elements (34) connected electrically to a control member of said motorcycle user. The pusher-type control elements (34) are associated with lever elements (21, 22) hinged to the annular body (2) and movably inserted into corresponding seats (20) of this latter, the elements (21, 22) cooperating with corresponding electrical members (35) inside the body to sense the movement or operation of the lever elements (21, 22) and generate an electrical signal directed to the control member of the motorcycle user, to modify the gear ratio upwards or downwards on the basis of the operated lever element (21, 22) in the case of the gear unit.