Urea granulation device

A fluidized bed granulator for granulation with urea or urea-containing liquids, the granulator comprising a granulator enclosure, wherein the granulator enclosure comprises:

• a lower wall, an upper wall, an inlet for fluidization gas, an inlet for secondary gas, an outlet for solid product particles, an outlet for exhaust gas, and optionally an inlet for seed particles,
• wherein the granulator enclosure comprises a plurality of granulation compartments, which are arranged in series in a length direction of the granulator,
• wherein the granulator further comprises an inlet for granulation liquid and a granulation liquid supply manifold, wherein the granulation liquid supply manifold comprises a granulation liquid header and a plurality of risers, wherein the granulation liquid header is connected to said inlet for granulation liquid and to a plurality of said risers,
• wherein the granulator enclosure further comprises a fluidization plate and at least in said granulation compartments a separation plate, wherein the separation plate is spaced apart from the fluidization plate in vertical direction and is placed below the fluidization plate, wherein the separation plate is arranged between said lower wall and said fluidization plate,
• wherein said granulator enclosure comprises a first space between said upper wall and said fluidization plate, a second space between said fluidization plate and said separation plate, and a third space between said separation plate and said lower wall, said first, second and third space each having an enclosure,
• wherein said granulator is configured for holding a fluidized bed of particles in operation in said first space, and wherein the enclosure of said first space comprises said outlet for solid product particles, said outlet for exhaust gas, and optionally said inlet for seed particles,
• wherein the enclosure of said second space comprises said inlet for fluidization gas, and wherein the fluidization plate comprises openings for passage of said fluidization gas from said second space to said first space,
• wherein said enclosure of said third space comprises said inlet for secondary gas,
• wherein the granulator comprises in said granulator compartments a plurality of nozzles for supplying said granulation liquid into said first space,
• wherein at least one of said nozzles comprises a nozzle inlet for said secondary gas and a nozzle inlet for said granulation liquid, wherein said granulator comprises a secondary gas channel which extends from a secondary gas opening in said separation plate through said second space to said nozzle inlet for secondary gas,
• wherein said granulation liquid supply manifold is in part provided in said third space and in part in said second space and wherein at least one of said risers is at least in part provided inside said secondary gas channel, wherein said riser passes through said secondary gas opening or is joined to said header at said secondary gas opening.