| 摘要 |
The invention relates to an energy-saving circuit of the rectification devices in continuous distillation plants and various embodiments of this circuit. Apart from the entire waste heat of the depleted solution stream, the entire heat of dephlegmation can also be used by this circuit over a wide separation range for preheating the enriched solution. This heat recovery becomes possible with a co-current dephlegmator which is connected, on the vapour side, in parallel to the enrichment section of the rectification column and is preferably cooled by a part-stream of the enriched solution. At the same time, product vapour at the required purity and condensate for the reflux of the enrichment section of the column relieved on the vapour side are recovered in this manner from a part-stream of the vapour mixture present at the beginning of the stripping section of the rectification column. In the case of an ammonia/water absorption heat pump, by this energy-saving circuit, for example, the heating efficiency index can be increased from 1.3 to 1.5 and in addition the heating water admission temperature can be increased from 65 DEG C to 80 DEG C. The annual energy consumption of the underlying heat pump-district heating plant would thus be decreased by 23%.
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