Reflux is used at the top of the catalytic fractionation tower
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According to the information I’ve read, one of the characteristics of a catalytic cracking fractionation tower is the use of recycle stream at the top of the tower. What does recycle stream mean? It is said that using cyclic reflux can reduce the pressure drop from the top of the tower to the compressor inlet, thereby lowering the power consumption of the compressor. What is the difference between this and cold reflux? Thank you, those who know please share
Circulating reflux refers primarily to the process in a catalytic cracking distillation column, where some of the liquid products from the top of the column are returned to the upper sections of the column, in order to control the temperature and composition within the column and to enhance the exchange of material and heat there. This operation can stabilize the quality of the product at the top of the tower, and it also helps to improve the separation efficiency of the entire plant. In the context of catalytic cracking, by increasing the tower top recycle flow, it is possible to reduce the pressure difference that must be overcome by the product vapor as it flows from the tower top to the compressor, thereby lowering the power requirements and energy consumption of the compressor. As for the difference from cold reflux, cold reflux generally refers to the operation of cooling the tower top product before returning it to the tower. This can directly reduce the temperature of the reflux liquid, affecting the temperature distribution within the tower; whereas cyclic reflux involves returning some of the hot liquid back into the tower without undergoing significant cooling. Both play a role in regulating the conditions inside the tower, but cold reflux places more emphasis on achieving better separation through temperature control. .
This post was last edited by liaifeng on 2024-4-16 at 16:46. Are you sure that the overhead reflux from the catalytic cracking distillation column does not go through extensive cooling?
Part of the liquid product at the top of the tower is recycled back to the upper part of the tower in order to exchange material and heat, facilitating the extraction of gasoline from the upper section and the separation of diesel from the lower section