reflux ratio/ minimum reflux/ optimum reflux in distillation column

Hi In this lecture we will discuss the reflux ratio. The reflux ratio is denoted by R which is equal to L/D. R = L/D Where L = liquid coming to top plate from the condenser where D is the distillate. At minimum reflux the operating cost is minimum while the fixed cost is maximum. As the reflux ratio is increasing the fixed cost decreases while operating cost increases. At higher reflux ratio the diameter of the column further increases so, the total cost increases at higher reflux ratio. Therefore it is best to use the optimum reflux ratio which is Ropt = (1.1 – 1.5)Rmin where Ropt is the optimum reflux ratio while Rmin is the minimum reflux ratio Thanks