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US 10,640,428 B2Granted
Removal of urea and ammonia from exhaust gases
AssigneeStamicarbon B.V.
InventorsJozef Hubert Meessen, Pantelis Orfanidis
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Abstract
The invention relates to a method for recovery of urea dust and ammonia from a gas stream by contacting said gas stream with an aqueous sulphuric acid solution, thus forming an acid solution of ammonium sulphate and urea, characterized in that the acid solution is concentrated to a melt comprising less than 5 wt % of water, which melt is subsequently transferred into solid particles comprising urea and ammonium sulphate.
Claims8
A method for converting urea dust and ammonia from a waste air stream comprising urea dust and ammonia into particles comprising urea and ammonium sulphate which method comprises
- (i) scrubbing said waste air stream comprising air, urea dust and ammonia with an aqueous sulphuric acid solution, thus forming an acidic solution of ammonium sulphate and urea;
- (ii) adding ammonia to the acid solution, thus forming a neutralized solution of urea and ammonium sulphate in water;
- (iii) concentrating the neutralized solution of (ii) to a melt comprising less than 5 wt % of water, and
- (iv) transforming the melt into solid particles comprising urea and ammonium sulphate;
- wherein the waste air stream is from urea granulation or urea prilling;
- and
- wherein step (iv) is performed in a pelletizer.
4 more elements
Dependencies are inferred from the claim text.