Method for prilling urea and urea prilling apparatus

A method for prilling urea using a urea prilling tower including an exhaust port provided at a tower top, a spraying portion for molten urea, a plurality of atmosphere inlet ports and a collection portion for prilled urea particles, in which

• the urea prilling tower is configured such that the spraying portion for molten urea is disposed on an upper side of the urea prilling tower, the plurality of atmosphere inlet ports are disposed on a lower side of the urea prilling tower, the collection portion is disposed at a tower bottom on a further lower side of the atmosphere inlet ports, and the plurality of atmosphere inlet ports are disposed at intervals in a circumferential direction,
• wherein, in a process of spraying the molten urea in an interior of the urea prilling tower, taking in an atmosphere at an ambient temperature of the urea prilling tower through the atmosphere inlet ports upwardly from below to cool and solidify the molten urea to form the urea particles,
• heating an interior of the urea prilling tower by supplying heating air having a temperature higher than the ambient temperature,
• the heating air at a temperature higher than the ambient temperature being supplied in addition to the atmosphere at the ambient temperature to heat the interior of the urea prilling tower.