Distillation of low-boiling components

• US 3,238,735 A
• Filed: 12/05/1962
• Issued: 03/08/1966
• Est. Priority Date: 12/05/1962
• Status: Expired due to Term

• Current Assignee: Howard R. Siewert
• Original Assignee: Howard R. Siewert
• Inventors: Siewert, Howard R.
• Application Number:
  US04/242,477
• Time in Patent Office: 1,189 Days
• US Class Current: 62/623
• CPC Class Codes: B01D 3/14 Fractional distillation or use of a fractionation or rectification column
• CPC Class Codes: C07C 7/04 by distillation
• CPC Class Codes: C07C 9/02 with one to four carbon atoms liquefied petroleum gas C10L3/12
• CPC Class Codes: F25J 2200/02 in a single pressure main column system
• CPC Class Codes: F25J 2200/30 using a side column in a single pressure column system
• CPC Class Codes: F25J 2200/74 Refluxing the column with at least a part of the partially condensed overhead gas
• CPC Class Codes: F25J 2210/12 Refinery or petrochemical off-gas
• CPC Class Codes: F25J 2270/12 External refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 2270/60 Closed external refrigeration cycle with single component refrigerant [SCR], e.g. C1-, C2- or C3-hydrocarbons
• CPC Class Codes: F25J 2270/90 External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
• CPC Class Codes: F25J 2290/40 Vertical layout or arrangement of cold equipments within in the cold box, e.g. columns, condensers, heat exchangers etc.
• CPC Class Codes: F25J 3/0219 Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
• CPC Class Codes: F25J 3/0233 separation of CnHm with 1 carbon atom or more
• CPC Class Codes: F25J 3/0242 separation of CnHm with 3 carbon atoms or more
• CPC Class Codes: Y10S 62/932 From natural gas

Claims

1. IN A PROCESS FOR SEPARATING A LOWER BOILING COMPONENT OF A DISTILLABLE MIXTURE FROM A HIGHER-BOILING COMPONENT THEREOF, COMPRISING FEEDING SAID MIXTURE TO A FRACTIONATION ZONE OPERATED AT A PRESSURE AT WHICH SAID HIGHERBOILING COMPONENT IS CONDENSIBLE AT A TEMPERATURE OBTAINABLE BY COOLING WATER IN THE SURROUNDINGS, WITH DRAWING AN OVERHEAD VAPOR PRODUCT COMPRISING SAID LOWERBOILING COMPONENT AND WITHDRAWING A BOTTOMS LIQUID PRODUCT COMPRISING SAID HIGHER BOILING COMPONENT, WHEREIN UPFLOWING VAPORS ARE GENERATED BY HEATING BELOW THE FEED POINT TO A TEMPERATURE SUBSTANTIALLY ABOVE ATMOSPHERIC IN ORDER TO KEEP THE CONCENTRATION OF LOWER-BOILING COMPONENT IN THE BOTTOMS LIQUID PRODUCT BELOW A SET MAXIMUM, AND WHEREIN REFRIGERATION MEANS IS USED TO SUPPLY TOP REFLUX AT A LOWER TEMPERATURE THAN IS NATURALLY OBTAINABLE IN THE SURROUNDINGS IN ORDER TO KEEP TO CONCENTRATION OF HIGHER-BOILING COMPONENT IN THE OVERHEAD VAPOR PRODUCT BELOW A SET MAXIMUM;

THE IMPROVEMNT FOR MINIMIZING THE REFRIGERATION WORK, WHICH COMPRISES;

WITHDRAWING ALL UPFLOWING VAPOR FROM THE FRACTIONATION ZONE AT A POINT ABOVE THE FEED POINT WHERE THE TEMPERATURE IS SUBSTANTIALLY ABOVE ATMOSPHERIC, PARTIALLY CONDENSING THE WITHDRAW VAPOR AT A TEMPERATURE OBTAINABLE BY COOLING WATER IN THE SURROUNDINGS, PASSING ONLY THE UNCONDENSIBLE PORTION OF THE WITHDRAWN VAPOR TO A RECTIFICATION SECTION OF SAID FRACTIONATION ZONE ABOVE THE POINT OF VAPOR WITHDRAWAL FOR COUNTERCURRENT CONTACT THEREIN WITH DOWNFLOWING TOP REFLUX SUPPLIED BY SAID REFRIGERATION MEANS, AND RETURNING THE RESULTING CONDENSED PORTION OF THE WITHDRAWN VAPOR TO THE FRACTIONATION ZONE BETWEEN THE FEED POINT AND THE POINT OF VAPOR WITHDRAWAL.