troductionA chemical plant spends approximately 50 to 90% of capital investment on separation equipment (1,1) Therefore, the ability to utilize a small laboratory column and to scale-up a column is an important skill for a chemical engineer.This report will outline the steps taken to design a packed distillation column. The column needs to separate a 50:50 mixture of ethanol and isopropanol into a distillate stream containing no more than 3 wt% isopropanol and a bottoms stream containing no more than 3 wt% ethanol. The design of the full-scale column was based on a laboratory simulation column. This column allowed the team to determine vapor velocities and HETP values for the 0.24 inch Pro-Pakq packing.Once the simulation vapor velocities are determined, they can be translated to the column design and used in the design of the reboiler and condenser. Areas for the reboiler and condenser will be found and costs will be calculated. Finally, the actual packing height will be determined for the scaled-up column.Theory and MethodsThe primary goal of this project was to deterimine the design specifications for a one foot diameter by forty foot high packed distillation column. The laboratory was run at total reflux. Total reflux occurs when the entire overhead vapor flow is returned as reflux and all of the bottoms liquid is returned as boil up. Total reflux is useful for starting up columns, maintaining column operation when all or part of a plant is shut down, or for our purposes: determining column efficiency. However, since our column was a packed column and not a tray or sieve plate column, efficiency is measured not in terms of overall efficiency, but in terms of HETP. HETP is defined as follows:HETP = height of column packing y number of theoretical stages(1)There are two basic ways to determine the number of theoretical stages (Nmin): McCabe Thiele analysis and/or using the Fenske equation. Both of these methods will give N...
