Patent ID: 6514387
Filing Date: 2003-02-04
Classification: B01D,Y10S

Abstract:
A rectifying column for extractive distillation of close-boiling or azeotropic boiling mixtures, comprisinga column main section (204) having two chambers (216, 217) connected in parallel; a raffinate section (205) located above the column main section; an evaporating device (208) located at a lower end of the column and having at least one evaporator (209); an arrangement (210) at a cap of the column with a raffinate drain (211), a condenser (212) and a device (213) for partly recycling the raffinate liquefied in the condenser; an inlet (214) located between the column main section (204) and the raffinate section (205) for feeding a starting mixture to be separated; and a solvent inlet located on a top side of the raffinate section for charging an extracting agent; wherein the chamber (216) of the column main section is open at the top and bottom sides and contains installations (207) designed as a stripping section with a plurality of separation stages for separating the raffinate from a mixture containing the extracting agent; and wherein the other chamber (217) is closed at the top side against the interior of the column and open at the bottom side and contains installations (207) having devices (218, 219) in a space above the installations for withdrawing a substantially extracting agent-free product in a gaseous state and for recycling a liquefied partial product stream; a column sump (221) connected at the lower end of the column with a solvent inlet (215) by a device (223) for withdrawing and recycling extracting agent; a column stripping section (222) with a plurality of theoretical separation stages arranged between the column sump (221) and the column main section (204), in which stripping section concentration of the extracting agent takes place from the top down; a catching tray (231) permeable to gas arranged below the column main section (204), a drain for liquid of said catching tray being connected to a continuous-flow heater (230) for heating liquid draining from the two chambers (216, 217) of the column main section (204), wherein the heated mixture exiting from the continuous-flow heater (230) can be fed below the catching tray (231) into the stripping section (222) of the column.