| 摘要 |
The present invention regards a process for the production of an aqueous solution comprising urea for use in the removal of nitrogen oxides from combustion gas or fumes, the process being characterised in that it comprises the steps of:
- subjecting at least a part of a urea-concentrated aqueous solution comprising residual free ammonia, obtained directly from or downstream of a recovery section of a plant for the production of urea, to washing with carbon dioxide, so obtaining a first vapour phase comprising carbon dioxide and optionally ammonia and a urea-concentrated aqueous solution comprising carbamate and essentially lacking in free ammonia, and
- diluting said urea-concentrated aqueous solution comprising carbamate and essentially lacking in free ammonia with water until the desired concentration of urea in aqueous solution is reached. |
