Patent GB-831979-A (GB)
Title: Method and apparatus for controlling catalytic processes
IPC: C08F10/00
Filed: 1956-08-16
Abstract: <PICT:0831979/III/1> A liquid-phase catalytic reaction, wherein catalyst and feed are introduced into a reaction zone and effluent from the reaction zone is separated into an unreacted component and a reaction product, is controlled by producing a control output which varies according to the rate of flow of the unreacted component from a separation zone and using this output to vary the ratio of catalyst to feed, so as to maintain constant the amount of unreacted feed in the effluent.  The process is especially suitable for the polymerization of olefines, e.g. ethylene (see Group IV (a)).  As shown, the reaction zone 10 is supplied with reactant feed through line 13, catalyst through line 17, and solvent through line 20, the reaction zone being maintained full of liquid.  Effluent reaction product flows through line 21 to heater 25 and flash separator 27, product being withdrawn at 31 and the gaseous fraction passing to condenser 36 and separator 37; liquid from separator 37 is returned via heater 40 to separator 27 and gas is removed at 41.  The rate of flow of effluent gas at 43 or 43a is maintained constant by controller 42 which in conjunction with controller 15 or 19 varies the amount of reactant or catalyst fed to the reactor.  The control output may be integrated to produce a value proportional to an average flow rate of unreacted component over a period of time.  The reactor pressure is maintained constant by controller 23, the temperature of the effluent entering separator 27 by controller 30, the level in separator 27 by controller 31b, and the pressure in separator 27 by controller 34.  In addition the temperature in the reactor may be maintained constant by controller 15a which varies the amount of coolant flowing through jacket 15e or the rate of feed in line 13.  In a modified process, a gas phase is maintained above the liquid phase in the reactor, the liquid level being controlled by varying the effluent flow, and the gas pressure by varying the feed flow.ALSO:Polymerization of olefines is carried out by a liquid phase process, in which catalyst and feed are introduced into a reaction zone and effluent from the reaction zone is separated into an unreacted component and a reaction product, and which is controlled by producing a control output which varies according to the rate of flow of the unreacted component from a separation zone and using this output to vary the ratio of catalyst to feed, so as to maintain constant the amount of unreacted feed in the effluent (see Groups III and XXXV).  Ethylene is polymerized at 285 DEG  F. and 500 lbs. per sq. inch pressure in the presence of a chromium oxide catalyst supported on silica, alumina, or silica-alumina. Reference is made also to the polymerization of propylene, 1-octene, and diolefines. The chromium oxide may alternatively be supported on zirconia or thoria and promoted with zinc oxide, magnesium oxide, or strontium oxide.  The catalyst is preferably introduced as a slurry in a hydrocarbon solvent, e.g. iso-octane, propane, normal butane, cyclohexane, or methylcyclohexane.