| 摘要 |
PURPOSE:To reduce the heat supply in the extractive distillation of a hydrocarbon mixture to obtain an easily soluble hydrocarbon, by providing a chimney tray having a heat exchanger at the bottom part of a distillation column and carrying out the concentration of the easily soluble hydrocarbon repeatedly, thereby increasing the theoretical plate number and reducing the reflux ratio. CONSTITUTION:A hydrocarbon mixture X is fed to an extractive distillation column DA and distilled in contact with the stream of an N-alkyl-substituted lower fatty acid amide solvent fed to the top of the column. The solvent solution containing a relatively easily soluble hydrocarbon flowed down from the tray 1 is collected on the chimney tray A, and introduced into a heat exchanger E. A part of the hydrocarbon is vaporized with a heat source (a hot lean solvent recovered from the bottom of a stripper DB) having a temperature slightly higher than that of steam or the chimney tray, returned to the chimney tray B, and separated into gas and liquid. The liquid is concentrated repeatedly (twice to five times) and introduced through a pipe 15 into the stripper DB to obtain concentrated easily soluble hydrocarbon Y. The eflux ratio can be reduced corresponding to the increase of the theoretical plate number, and the sensible heat of the solvent can be effectively utilized. |
