| 摘要 |
In a process for the separation of carbon dioxide from gaseous mixtures comprising carbon dioxide and ammonia by scrubbing <PICT:0745406/III/1> the mixture with a cooled aqueous solution of a weak base capable of reversible combination with carbon dioxide, e.g. monoethanolamine so as to absorb both the carbon dioxide and ammonia, subjecting the enriched solvent to a limited heating to expel the ammonia, subjecting the solvent to a further heating at a higher temperature so as to expel most of the carbon dioxide, and finally returning the solvent to the scrubbing step, the expelled ammonia is recovered after reacyling to the scrubbing step. The recycled solvent may be maintained in a purified condition by continuously bleeding off a portion, distilling in the presence of alkali and returning to the cycle. The solvent may contain a decomposition inhibitor, e.g. copper iodide or a vanadium compound. As shown a gaseous mixture comprising carbon dioxide and ammonia is introduced via an upflow line 5 into a system comprising an absorber 1, stripping column 2, and heater 3, the absorber and stripping column being connected by downflow line 4 for the absorbing liquid and upflow line 5 for the evolved ammonia gas. The solution in the absorber is thus continually saturated with ammonia, the excess being passed through an alkali scrubber 7 to produce ammonia free from carbon dioxide at 12a. The car bon dioxide which is substantially completely absorbed is recovered at 25 by passing the solution from stripping column 2 viat heat exchanger 16 into a system comprising regenerating tower 18, heater 19 and solvent condenser 22. The regenerated solvent is returned via heat exchanger 16 to absorber 1. |
