PROCESS AND PLANT FOR THE PRODUCTION OF A UREA SOLUTION FOR USE IN SCR PROCESS FOR REDUCTION OF NOX

摘要

A process and a plant for the preparation of an acqueous solution of urea suitable for use in a SCR process for nitrogen oxides removal, wherein the urea solution from the recovery section of a urea plant is subject to at least one step of evaporation, separating a vapour stream containing water and ammonia, and obtaining a concentrated and substantially ammonia-free solution, and said concentrated solution is diluted to the concentration of urea suitable for use in the SCR process.

主权项

1. A process for the preparation of an aqueous solution of urea suitable for use in a SCR process for nitrogen oxides removal, comprising the steps of:
obtaining an aqueous stream containing urea by dissociation of carbamate in a recovery section of a urea production plant which operates at a lower pressure than a synthesis section of the plant; subjecting said acqueous stream to at least one process step of evaporation, thereby separating a vapour stream containing water and ammonia, and obtaining a concentrated and substantially ammonia-free solution; and then diluting said concentrated solution to obtain a solution with a concentration of urea suitable for use in the SCR process.