3 replies to this topic

[aliadnan]

Dear Fellows

Always start the project search from the Encyclopideas. They are the best source of information and you will find references to other literature also from there. Try

1 ) McKetta, J.J, ”Encyclopedia of Chemical Processing and Design”
2 ) Encylopedia of Chemical Engineering by Kirk Othmer
3 ) Shreves "Chemical Process Industries Handbook"
4) lang's "Chemistry handbook"
5)Handbook of industrial chemistry by Reigel

Hope this helps

Regards
Ali

[abhi_agrawa]

Andres,
I worked for a small time in a DAP plant, but that was about 7-8 years ago. So I do not remember the process conditions, but I'll try to explain to you the process. In this process, liquid ammonia is reacted with hot Phosphoric Acid in a CSTR to produce Monoammonium Phosphate (MAP). Then this hot solution of MAP is sprayed on to fines, this is done in a granulator. Liquid ammonia is also injected in the granulator. The product from the granulator is DAP. The hot product is dried and then cooled. After cooling, the product is sent to screens, where it is separated into fines, on-specification and over sized particles. The fines are recycled to the granulator and the over sized are crushed and returned to the screens.
I will try to see if I have some process data, but the chnces are remote.
The art in this process is cooling the product. If the product is cooled suddenly, it will give thermal shocks to the granules and the quality will not be too good. If the cooling is slow, then there are chances of the product picking up moisture. A number of granules can also coalesce and form a large granule if to cooling is slow.
Another important point from the point of operation is maintaining the Nitrogen to Phosphorus ratio in the reactors.
As far as the design of the process is concerned, the design of the franulator is the key.

-abhishek