Please check the following so you get an idea of what you are getting into:
1) Ureaknowhow.com has published a document with the title: "2017 12 Cotabarren Production of Granular Urea as Nitrogenous Fertilizer"
2) Also look for the publication: "Analysis of the product granulometry, temperature and mass flow of an industrial
multichamber fluidized bed urea granulator" Published in "Powder Technology" ini 2011
3) Handbook of Powder Technology. Volume 11:
https://books.google...ulation&f=false
Regarding your questions:
- Dimensions: Depend on your scale
- Mass and Energy Balances: This is a complicated issue. Because you need Mass, Energy AND number of particles balances.
- Costings : No idea
- Safety Standards: Same as any chemical plant. Main risk is molten urea and formadehyde. Some jurisdictions may impose limits on plume visibility.
- Materials of construction: Mostly stainless steel. I believe that 304 is enough for everything in contact with powder. For molten urea is 316 Urea Grade. Compressed air and steam is CS.
- Enthalpies: See the refered documents