A smoker equation based algorithm for binary distillation design calculations

Abstract

An algorithm- based on smoker’s analytical equation- suitable for the development of computer programs, for the determination of some design parameters of a binary distillation column was presented. A sample problem presented by Richardson et. al. (2003) was modified, with respect to constant relative volatility, and solved using the algorithm. We compared the solution obtained using the algorithm to that by Backhurst and Harker (1999) using McCabe-Thiele method. The deviation of 4.25% observed can be explained based on the assumption of constant relative volatility. This deviation is not only acceptable in comparison to a deviation of about 23.25% that could exist between solutions obtained using McMabe-Thiele and Fenske’s method at total reflux, but also safe since it does not reduce but adds to the number of theoretical plates, thus ensuring that operational targets of purity in the product are met. Apart from suitability under normal conditions, the algorithm is suitable when concentration of more volatile component of either product is very low or relative volatility is low, conditions under which the McCabe-Thiele method is impracticable.