COMPARISON OF ENERGY SAVING METHODS FOR DISTILLATION OF LIQUID MIXTURES

Abstract

The analysis and review of the scientific literature on methods and approaches to energy saving in distillation, as one of the most energy-intensive processes for the separation of binary and multicomponent mixtures was carried out. Directions of the scientific literature are highlighted, showing the relevance of the thermodynamic method assessment of separation processes. A comparative analysis of various methods of energy conservation in the separation of liquid binary mixtures by the distillation method is performed (a binary mixture of benzene-toluene was chosen as an example). A conventional distillation column as well as a column with a heat pump and a column with heat integration were considered. As a result of the calculation experiment for each option performed using the Aspen Plus software package the optimal column parameters were determined - the total number of stages and the position of feed stage. The heat consumption in the column boiler was taken as the objective function. It is also shown that with the same characteristics of the columns, the best way to organize the process for separating the selected mixture is to compress the steam stream from rectifying profile of the column with its subsequent use in the boiler of the stripping profile according to the principle of a heat pump. It was established by a calculation experiment that heat integration by compressing steam from rectifying profile of the column and supplying it to the stripping profile gives significantly less energy saving. The calculation of internal energy saving by distillation column was carried out and it was shown that the distributed heat removal from the plates of the rectifying profile of the column and the supply of this heat to the stripping profile plates reduces internal energy saving and leads to an additional increase in heat consumption in the boiler.