2022 Annual Meeting
Process Intensification: Two Enthalpy Feed Explained By Exergy for Use in Distillation
In the current industrial scenario, distillation has emerged as one of the most crucial separation techniques for separating homogenous mixtures into useful end-products based on their boiling point difference or relative volatility. The humongous energy requirements of the process has become a matter of serious concern lately. The problem lies in optimal utilisation of energy that is to increase the exergy which will automatically cut down the energy requirements of the process. The most rudimentary technique that is often followed to lower down energy usage is by integrating the columnâs bottom product heat with the feed. Though this brings about a significant reduction in the reboiler duty as the feed vaporization percentage increases, but it triggers an upward surge in the reflux ratio (from McCabe-Thiele Method) causing the condenser duty to rise. In this work, the scheme proposed for improvement is the splitting of the feed, preheating one and placing the two feeds at different stages in the column. This two enthalpy feed with different enthalpies but same composition generates an additional driving force due to gradient in chemical potential that increases separation which aids in utilisation of the waste heat effectively. With this approach, efficiencies close to 100% can be achieved by splitting the feed and changing the thermal condition of a part of the feed. Apart from this, the use of two enthalpy feed has several advantages which has been discussed in the paper. Incorporating this strategy can help us achieve process intensification inside the refinery.