Fluid bed granulation for high efficiency and excellent quality
The urea melt from the evaporation section is fed to the fluid bed granulation unit and further processed to high-grade solid granules. Formaldehyde is injected into the urea melt as a granulation agent before it is sent to the granulator.
The granulated product extracted from the granulator is cooled down and lifted to the screening section. The oversize material is crushed and returned as seeding particles to the granulator together with the undersize grains. After final cooling, the specification-grade product is sent to the storage facility.
The granules produced by this technology are round and very hard and therefore highly resistant to crushing and abrasion. They can be produced in a wide range of defined sizes.
Urea dust, which is entrained in the air from the granulator, the fluidized-bed coolers and various dedusting points, is recovered in a scrubbing system. Process condensate from the desorption section is used as make-up water for the scrubbing liquid, which is recycled to the evaporation section.
Because of its high efficiency and a granulator that ensures excellent product quality with extremely low solid recycle rates, the fluid bed granulation process by Uhde Fertilizer Technology is the leading granulation technology. It permits the construction of single-train granulation plants which are in line with the largest synthesis units so far constructed. The process conforms to the most stringent environmental laws as there is no waste water and only minimum dust emissions. Maximum operating flexibility and reliability as well as minimum maintenance and operating staff requirements are further features of this advanced process, which is used in more than 70 urea plants worldwide.