SEPARATION OF ACETYLENE AND ETHYLENE FROM CRACKED GAS

• US 3,607,963 A
• Filed: 02/10/1969
• Issued: 09/21/1971
• Est. Priority Date: 02/13/1968
• Status: Expired due to Term

• Current Assignee: Axel Danneil, Kurt Taglieber, Otto Nagel, Rolf Platz
• Original Assignee: Axel Danneil, Kurt Taglieber, Otto Nagel, Rolf Platz
• Inventors: Nagel, Otto, Platz, Rolf, Taglieber, Kurt, Danneil, Axel
• Primary Examiner(s): Yudkoff, Norman
• Assistant Examiner(s): Purcell, Arthur F.
• Application Number:
  US04/798,041
• Time in Patent Office: 953 Days
• Field of Search: 62/23,24,27,28,39 260/683,679
• US Class Current: 62/634
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: F25J 2200/74 Refluxing the column with at least a part of the partially condensed overhead gas
• CPC Class Codes: F25J 2205/04 in the feed line, i.e. upstream of the fractionation step
• CPC Class Codes: F25J 2205/50 using absorption, i.e. with selective solvents or lean oil, heavier CnHm and including generally a regeneration step for the solvent or lean oil
• CPC Class Codes: F25J 2210/12 Refinery or petrochemical off-gas
• CPC Class Codes: F25J 2215/62 Ethane or ethylene
• CPC Class Codes: F25J 2245/02 Recycle of a stream in general, e.g. a by-pass stream
• CPC Class Codes: F25J 2270/04 Internal refrigeration with work-producing gas expansion loop
• 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 3/0238 separation of CnHm with 2 carbon atoms or more
• CPC Class Codes: F25J 3/0271 separation of H2/CO mixtures, i.e. of synthesis gas production of carbon monoxide containing gas in general C01B32/40, C10J, C10K, production of hydrogen containing gas C01B3/00

Abstract

Joint separation of acetylene and ethylene from cracked gas, obtained by submerged-flame methods, by condensing the hydrocarbons in one or more stages by cooling to a temperature above the solidification temperature of acetylene in admixture with the other condensable constituents, separating the condensate, washing the residual gas mixture with liquid ethylene and/or ethane, and further cooling the gas mixture free from acetylene to -140* to -170* C.

Claims

2. In a method of joint separation of acetylene and ethylene from cracked gas which has been obtained by cracking liquid hydrocarbon fractions by means of a flame burning beneath the surface of said hydrocarbons from which the carbon dioxide and hydrogen sulfide have been removed and the cracked gas is dried by condensation the improvement which comprises cooling said hydrocarbons to a temperature which is above the solidification temperature of acetylene in admixture with the other condensable constituents and which is in the range of -82* to -120* C., the condensate thus obtained being separated and the remaining gas mixture containing small amounts of acetylene being freed from acetylene by scrubbing with a liquid consisting of ethylene, ethane or a mixture thereof, the gas mixture devoid of acetylene then being cooled to from -140* to -170* C., separating the condensate from the gas which has been cooled to from -140* to -170* C., warming said gas to -130 * to -100* C. countercurrent to the gas leaving the ethylene scrubber, and flashing said gas in a flash unit while performing external work so that the gas mixture is cooled and is used for countercurrent cooling in the condensation stages.

3. In a method as claimed in claim 1 the improvement which comprises using the condensate obtained by cooling to from -140* to -170* C. as the scrubbing liquid.

4. In a method as claimed in claim 2 the improvement which comprises using the condensate obtained by cooling to from -140* to -170* C. as the scrubbing liquid.