Process and apparatus for fractionating close boiling components of a multi-component system

• US 4,315,802 A
• Filed: 05/12/1980
• Issued: 02/16/1982
• Est. Priority Date: 05/12/1980
• Status: Expired due to Term

• Current Assignee: The Lummus Company
• Original Assignee: The Lummus Company
• Inventors: Tsao, Utah
• Primary Examiner(s): Sever, Frank
• Application Number:
  US06/148,977
• Time in Patent Office: 645 Days
• Field of Search: 423/580, 203/5, 203/21, 203/22, 203/24, 203/25, 203/26, 62/23, 62/30, 62/38, 62/39, 62/41, 202/158, 202/182, 202/233-235, 196/134, 196/139
• US Class Current: 202/158
• CPC Class Codes: B01D 1/2846 The compressed vapour is not directed to the same apparatus from which the vapour was taken off
• CPC Class Codes: B01D 1/2856 The compressed vapour is used for heating a reboiler or a heat exchanger outside an evaporator
• CPC Class Codes: B01D 3/146 Multiple effect distillation
• CPC Class Codes: B01D 3/322 Reboiler specifications
• CPC Class Codes: C01B 5/02 Heavy water; Preparation by chemical reaction of hydrogen isotopes or their compounds, e.g. 4ND3 + 7O2 ---> 4NO2 + 6D2O, 2D2 + O2 ---> 2D2O

Abstract

There is disclosed a process and apparatus for the fractionation of close boiling components of a multi-component system and comprised of at least two fractionation columns having a plurality of equilibrium stages wherein the vapor from a downstream fractionation column is compressed and passed into a lower portion of a preceding fractionation column. In a particularly preferred embodiment, the compressed overhead vapor stream is passed in heat transfer relationship to a liquid stream withdrawn from the preceding fractionation column prior to introduction into the lower portion of such preceding fractionation column.

Claims

1. In an apparatus for fractionating close-boiling components of a multi-component system in a plurality of fractionation columns wherein there are at least two of said columns in series, said plurality of columns being of like operating pressures, wherein a conduit for liquid is provided for passing a liquid bottoms from a penultimate fractionation column to an upper portion of the last fractionation column of said series and wherein a conduit for vapor is provided for withdrawing a vapor stream from the upper portion of said last fractionation column and wherein a higher boiling component of said multi-component system is withdrawn as a liquid from said last fractionation column and wherein a lower boiling component of said multi-component system is withdrawn as a vapor, an improved apparatus which comprises:

means for eliminating the requirement for a pump, comprising a first conduit having an orifice therein, for feeding from the bottom of said first column;

aid orifice being sized, and spaced sufficiently below said bottom to provide self venting; and

means for eliminating the requirement of a reboiler in said first column, comprising a second conduit having a compressor therein for feeding from the top of said last column to the bottom of said first column.

2. The apparatus as defined in claim 1 and further including a heat exchanger for said liquid conduit and conduit means for cooling said compressed vapor stream.

3. The apparatus as defined in claim 1 wherein a restriction orifice is disposed in said liquid conduit with a head level of at least five feet.

4. The apparatus as defined in claim 1 wherein there are more than two fractionation columns, and further including a compressor means in a vapor conduit between said next to last fractionation column and a preceding fractionation column.