GB1310975A - Method of and apparatus for regulating the temperature and conversi on in a polymerization reactor - Google Patents

Abstract

1310975 Automatic control of temperature & fluid flow rate SNAM PROGETTI SpA 16 July 1970 [21 July 1969] 34622/70 Heading G3R Relates to a method of regulating the temperature of and degree of conversion in a polymerization reaction in which at least one polymerizable monomer is fed to a reactor together with a catalyst dissolved or suspended in a liquid medium, by controlling the feedrate of the catalyst and the temperature of the liquid medium. In the drawing thick lines represent pipe lines for process fluids and thin lines represent electrical connections. Monomer is fed at a constant rate and temperature via pipe-line 1 to a reactor vessel 5 and the polymerized product is discharged through 6. A pipe-line 3 conveys a catalyst dissolved in a solvent, at a constant composition and temperature but variable flowrate. A line 4 conveys the majority of the solvent at a variable temperature, solvent streams in lines 13, 14 and at different temperatures being fed via a controlled mixing valve 12 and a combined stream at an adjusted temperature being fed to the pipe-line 4. The flow-rates in the pipe-lines 3, 4 are regulated by controlled valves 20, 16 so that the solvent and catalyst conveyed by line 2 to the reactor, flows at a constant rate. ELECTRICAL CONTROL ARRANGEMENT The reaction temperature is measured by a sensor 7 in the reactor or pipe-line 6 and is compared in a comparator 8 with a desired reaction temperature signal in a conductor 9. The comparator 8 output is compared in a comparator 10 with the solvent/catalyst temperature in pipe-line 2 and measured by a sensor 11. The resulting output from comparator 10 controls the mixing valve 12 as described above, whereby the solvent temperature in pipe-line 4 and hence in pipe 2, is maintained at a value imposed by comparator 8. The flow-rate in pipe 2 is sensed by a unit 15 which controls valve 16 to adjust the flow-rate in pipe 4 in conjunction with any flow-rate changes in pipe 3, whereby to maintain a constant flowrate in pipe 2. A signal representing the desired degree of monomer conversion is fed via a conductor 21 to a signal processor 22, together with the desired reaction temperature signal in conductor 9. The processor 22 produces a control signal therefrom in a conductor 18. This signal is compared with the solvent/catalyst temperature sensed by 11, in a comparator 17, the output of which is fed as a reference value to a regulator 19. The regulator 19 also receives an input significant of the flow-rate of catalyst/ solvent in pipe 3 and regulates the said flow-rate accordingly, by means of the valve 20. Thus the reference control signal in conductor 18 is such that the difference between the temperature of solvent entering the reactor vessel 5 as measured by 11 and the temperature of product discharged therefrom as measured by 7, corresponds to the heat developed by the reaction in accordance with the desired degree of monomer conversion.