Patent GB-474377-A (GB)
Title: Preparation of gases for polymerization
IPC: C07C7/00
Filed: 1936-04-29
Abstract: <PICT:0474377/IV/1> Hydrocarbons readily polymerizable to low boiling liquids, admixed only with saturated hydrocarbons containing 3 and 4 carbon atoms and possibly ethane, are obtained from a crude gas containing them together with higher and lower boiling hydrocarbons by first separating non-carbonaceous gases and methane and permissibly part of the hydrocarbons containing 2 carbon atoms, and then treating the remaining gases to eliminate hydrocarbons having 5 or more carbon atoms.  A preliminary separation of sulphurous gases and entrained liquid may be effected.  Gases and vapours from a crude oil topping unit, cracking plant, coking unit or the like are discharged into a fractionator 2, and the overhead material passes to a condenser 4 and separator 5 for removal of liquid, through a purifier 7a for removal of sulphurous gases, if necessary, and thence to the first separating zone which may be a fractionation zone but preferably utilizes a selective adsorbent such as carbon, silica gel or activated alumina.  This is contained in vessels 8, 8a, 8b which receive the gases from a line 9, non-carbonaceous gases, methane, and possibly part of the C2 hydrocarbons which are not adsorbed leaving by a line 10.  The adsorbed gases are ejected, for example, by high pressure steam supplied from line 11 and leave by a line 12.  Any remaining steam is removed by connection to a vacuum line 13.  The vessels are used in sequence so that a continuous stream of gas passes to the second separating zone comprising a fractionating tower 14.  This operates at the pressure imposed by the ejecting agent which is that required in the subsequent polymerization zone 17, for example, 150 lbs. upwards.  Heavy material leaves by line 15.  If the selected hydrocarbons contain a high proportion of paraffins, they may pass to a catalytic or thermal cracking zone prior to polymerization.ALSO:<PICT:0474377/III/1> Hydrocarbons readily polymerizable to low boiling liquids, admixed only with saturated hydrocarbons containing 3 and 4 carbon atoms and possibly ethane, are obtained from a crude gas containing them together with higher and lower boiling hydrocarbons by first separating non-carbonaceous gases and methane and permissably part of the hydrocarbons containing 2 carbon atoms, and then treating the remaining gases to eliminate hydrocarbons having 5 or more carbon atoms.  A preliminary separation of sulphurous gases and entrained liquid may be effected.  Gases and vapours from a crude oil topping unit, cracking plant, coking unit or the like are discharged into a fractionator 2, and the overhead material passes to a condenser 4 and separator 5 for removal of liquid, through a purifier 7a for removal of sulphurous gases, if necessary, and thence to the first separating zone which preferably utilizes a selective adsorbent such as carbon, silica gel or activated alumina.  This is contained in vessels 8, 8a, 8b which receive the gases from a line 9, non-carbonaceous gases, methane, and possibly part of the C2 hydrocarbons which are not adsorbed leaving by a line 10.  The adsorbed gases are ejected, for example, by high pressure steam supplied from line 11 and leave by a line 12. Any remaining steam is removed by connection to a vacuum line 13. The vessels are used in sequence so that a continuous stream of gas passes to the second separating zone comprising a fractionating tower 14.  This operates at the pressure imposed by the ejecting agent which is that required in the subsequent polymerization zone 17, for example 150 lb. upwards.