EP0053410A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Process for the removal of urea, ammonia and carbon dioxide from dilute aqueous solutions
Assignee: Unie Van Kunstmestfabrieken BV
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Filing: 1981-10-31
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Granted: —
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Expires: 2001-10-31
Abstract
Abstract Removal of urea, ammonia and carbon dioxide from diluted aqueous solutions, for instance urea process effluent, the solution being led into the top of a reaction column under a pressure of 10-30 bar, in which it flows down in counter-current to a flow of gas, for instance steam. The temperature in the top of the reaction column is 170-220°C; at the bottom, it is 180-230°C. Next, at a pressure of 1-5 bar, ammonia and carbon dioxide are removed from the urea-free bottom solution. The remaining solution contains less than 10 ppm urea and less than 10 ppm ammonia.
Inventors
- 👤 Jan Zuidam
- 👤 Petrus Johannes Marie Van Nassau
- 👤 Pierre Gerard Marie Bernard Bruls
- 👤 Kees Jonckers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 21:54
CPC Classifications
B; B01; B01D; B01D3/00; B01D3/14; B01D3/26; C; C02; C02F; C02F9/00; B01D17/00; C02F1/00; C02F1/58; C02F1/586; C07; C07C; C07C273/00; C07C273/02; C07C273/04; C02F1/02; C02F1/025; C02F1/04; C02F1/048; C02F2101/00; C02F2101/10; C02F2101/16
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
143 words
Process for the removal of urea, ammonia and carbon dioxide from dilute aqueous solutions by hydrolysis of urea, followed by desorption of ammonia and carbon dioxide, characterized in that the solution is passed at a pressure of between 10 and 30 bar into the top of a reaction column and is caused to flow downward therein countercurrently to a gas stream, in the top of which column a temperature of between ween 70 and 220 °C is maintained and in the bottom of which temperature of between 180 and 230 °C is maintained, a gas mixture containing ammonia, carbon dioxide and water vapour is carried off from the top of the column and from the bottom a substantially urea-free aqueous solution of ammonia and carbon dioxide and subsequently, at a pressure of 1-5 bar, ammonia and carbon dioxide are removed from this solution.
Claim 2
Dependent Claim
143 words
Process for the removal of urea, ammonia and carbon dioxide from dilute aqueous solutions by hydrolysis of urea, followed by desorption of ammonia and carbon dioxide, characterized in that the solution is passed at a pressure of between 10 and 30 bar into the top of a reaction column and is caused to flow downward therein countercurrently to a gas stream, in the top of which column a temperature of between ween 70 and 220 °C is maintained and in the bottom of which temperature of between 180 and 230 °C is maintained, a gas mixture containing ammonia, carbon dioxide and water vapour is carried off from the top of the column and from the bottom a substantially urea-free aqueous solution of ammonia and carbon dioxide and subsequently, at a pressure of 1-5 bar, ammonia and carbon dioxide are removed from this solution.
Claim 3
Dependent Claim
44 words
Process according to claim 1, characterized in that, prior to the treatment in the reaction column, ammonia and carbon dioxide are removed, in a pre-desorption zone in which a pressure of 1-5 bar is maintained, from the solution containing urea, ammonia and carbon dioxide.
Claim 4
Dependent Claim
22 words
Process according to claim 1 or 2, characterized in that in the reaction column steam is used as the said gas stream.
Claim 5
Dependent Claim
17 words
Process according to claim 3, characterized in that steam with a pressure of 15-42 bar is used.
Claim 6
Dependent Claim
34 words
Process according to any one of the claims 1-4, characterized in that ammonia and carbondioxide are removed from the solution carried off from the bottom of the reaction column by countercurrently stripping with steam.
Claim 7
Dependent Claim
38 words
Process according to any one of the claims 1-5, characterized in that the solution to be fed to the reaction column is pre-heated by heat exchange with the solution carried off from the bottom of the reaction column.
Claim 8
Dependent Claim
38 words
Process according to any one of the claims 2-6, characterized in that, after expansion to a pressure of 1-5 bar, the gas mixture carried of from the top of the reaction column is passed into the pre-desorption zone
Claim 9
Dependent Claim
40 words
Process according to any one of the claims 2-7, characterized in that the gas mixture containing the ammonia and carbon dioxide separated from the solution carried off from the bottom of the reaction column is passed into the pre-desorption zone.
Claim 10
Dependent Claim
45 words
Process according to any one of the claims 2-8, characterized in that the gas mixture carried off from the pre-desorption is condensed and the dilute aqueous solution of ammonia and carbon dioxide thus obtained is worked-up, at least in part, in the preparation of urea.
Claim 11
Dependent Claim
23 words
Process for the removal of urea, ammonia and carbon dioxide from dilute aqueous solutions as described and elucidated by means of the example.
Claim 12
Dependent Claim
23 words
Process for the removal of urea, ammonia and carbon dioxide from dilute aqueous solutions as described and elucidated by means of the example.
References Cited (Backward Citations)
GB1071929A
Cited
US3357901A
Cited
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