Activity monitoring and polymerization process control

摘要

The present invention relates to a method to control a liquid feed stream carried out by measuring at least one spectrum of the liquid feed stream comprising an initiator or catalyst, determining its activity using a predictive model on the basis of said spectrum and adjusting the feed streams and/or the preparation conditions of the feed stream comprising the initiators or catalysts in order to attain or maintain a desired level of total activity. In a further aspect the invention relates to a controlled process for the preparation of polymers in a polymerization reactor by contacting liquid feed streams comprising monomers and initiators or catalysts, whereby the control of the feed streams entering the polymerization reactor and/or the initiator or catalyst preparation is carried out by measuring at least one spectrum of the liquid feed stream comprising an initiator or catalyst, determining its activity using a predictive model on the basis of said spectrum and adjusting the feed streams and/or the preparation conditions of the feed stream comprising the initiators or catalysts in order to attain or maintain a desired level of total activity within the polymerization reactor. More particularly, the invention relates to a method for controlling the activity of aluminum containing initiators in a process for the co-polymerization of isolefins and multiolefins, in particular isobutylene and isoprene. The present invention further to device and a chemical plant suitable to operate said process.

主权项

1. A controlled process for the preparation of polymers, the process comprising:
a) preparing an active first liquid medium comprising at least one polymerisation catalyst or at least one polymerisation initiator; b) contacting in a polymerization reactor
a volume of a first feed stream of the active first liquid medium, witha volume of a second feed stream of a second liquid medium comprising an amount of at least one polymerizable monomer,to form a reaction medium, wherein the at least one polymerizable monomer polymerizes within the reaction medium to form a product medium comprising a polymer, and during the contacting, controlling at least one of the first feed stream and the second feed stream by:
i) measuring at least one spectrum of the active first liquid medium;ii) determining the specific activity (aspecific) of the active first liquid medium using a predictive model;iii) determining a desired volume ratio (Rdesired) of the active first liquid medium and the second liquid medium necessary to obtain a desired ratio of total activity aTotal (=aspecific×V1) and the amount of monomer contained in the second feed stream, wherein V1 is the volume of the first feed stream; and iv) controlling
the volume V1 of the first feed stream, orthe volume V2 of the second feed stream, orboth volumes V1 and V2entering the polymerization reactor in such a manner, that the volume ratio of V1 and V2 at least converges to Rdesired; and whereby the predictive model is generated by a process comprising:
A) measuring spectra for a plurality of active liquid media having different activity;B) determining the specific activity (aspecific) for the plurality of active liquid media by their employment in a polymerisation reaction with known volumes V1 and V2 and a known amount of the at least one monomer and analysis of the polymer formed thereby, whereby the polymerisation reaction proceeds substantially via the same mechanism as the polymerisation in step b); andC) correlating the spectra of the active liquid media measured in step A) with their specific activity (aspecific) determined in step B).