CONCEPTUAL DESIGN OF SIMPLE DISTILLATION COLUMNS Goals: u Determine feasibility of proposed separation u Estimate tray and reflux requirements u Estimate column diameter and height 9/27/99 Simple Distillation Design 1 DEFINITION OF SIMPLE DISTILLATION u A distillation column with a single feed and no side streams u Vapor-liquid equilibrium ð Ideal (Raoult’s Law) ð Nearly ideal (modified Raoult’s Law) ð No azeotropes u Modest heat effects - no substantial variations in vapor and liquid traffic above and below the feed 9/27/99 Simple Distillation Design 2 REQUIREMENTS FOR A FEASIBLE DESIGN u Achieve product specifications ð Purity ð Fractional recovery u Reboil and condense using availability utilities u Column diameter and height should be within fabricatable limits ð Diameter < 7 m ð Height < 35 m 9/27/99 Simple Distillation Design 3 Distillation Column Design Procedure Determine Calculate Column Specs Modify Minimum Reflux and Constraints Requirement (Underwood) Choose Reflux Rate Estimate Overall Set Column and Estimate Tray Efficiency Operating Theoretical Tray (O'Connell, Pressure Requirement (Gilliland) Murphree) Calculate Vapor Calculate Actual No and Liquid Trays Required OK? Traffic and Column VB, VT, LB, LT Height (HCOL) Yes Calculate Calculate Column Mininum Tray Diameter No Ab
