EXTRACTIVE DISTILLATION COLUMN &= nbsp;

Liquid hydrous ethanol is drawn from the 190 Proof tank, TK-801 and is pumped under flow control by the E. D. Feed Pump, P-549, thro= ugh the E. D. Column Feed Preheater, E-551 for preh= eating and into the Extractive Distillation Column, T-552. The Extractive Distillation Column= has 60 perforated trays. There ar= e feed trays at trays #42, #46, and #50. The design feed tray is tray #46.

Ethanol is distilled in the Extractive Distillation = under high dilution with water. Ope= rating the column in this manner causes light boiling impurities (heads), propanol= s, and fusel oils to be driven up the column where= they can be drawn from the system. Purified ethanol is driven down the column. The column is operated under press= ure in order to cascade heat into the downstream H.Q. Stripper/Rectifier that is operating at atmospheric pressure.

Overhead vapor from the Extractive Distillation Colu= mn passes through a pressure control valve and is nearly all condensed in the = E. D. Condenser, E-562. The condensed liquid is pumped und= er level control by the E. D. Reflux Pump, P-563 back to the E. D. Column.

A portion of uncondensed vapor is taken from the E. = D. Condenser under flow control and is directed to the E. D. Heads Condenser, E-564, where it is condensed.

A product side stream is taken under flow control fr= om the E. D. Column at tray #13 and becomes feed to the H.Q. Stripper/Rectifier. The draw point is just below the p= inch zone of the column. The setpoint for the flow controller can be reset by casc= ade control from the temperature of the column to maintain the proper temperatu= re profile in the column. The H.= Q. Stripper/Rectifier feed stream first heats the incoming dilution water in t= he Dilution Water Preheater #2, E-553. It then preheats the E. D. feed in= the E. D. Feed Preheater, E-551. It then provides some reboiling for the Demethylizer, T-566, in the Demethy= lizer Reboiler #2, E‑571. It = then enters the H. Q. Stripper/Rectifier, T-557.

The E. D. Column is reboiled by the E. D. Reboiler, E-555 using 125 psig steam.<= span style=3D'mso-spacerun:yes'> The bottoms stream exits the Extra= ctive Distillation Column and is pumped under flow control by the E. D. Bottoms P= ump, P-556, back to the E. D. Column at the dilution water feed tray. Heat is recovered from the steam c= ondensate in the Dilution Water Preheater #1, E-577 before entering the Steam Flash Drum, D-585.

The amount of dilution water entering the E. D. Colu= mn is flow controlled. There are fe= ed trays at tray #56, tray #58, tray #59 and tray #60. The design tray is tray #58.

If required, antifoam is added to the Extractive Distillation Column via the Antifoam Tank, TK-542 and the Antifoam Pump, P-546.