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Real Time On Line Process for Continuous Polymerization of Styrene-Butadiene Latex

IP.com Disclosure Number: IPCOM000094780D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 59K

Publishing Venue

IBM

Related People

Cooper, HR: AUTHOR

Abstract

This computer controlled process is for emulsion polymerization of styrene-butadiene rubber. Shown is a cold rubber system. Raw materials. such as styrene, butadiene, etc., are fed into a reactor unit. Normally, such a unit consists of twelve kettle-type vessels with agitators. Cold rubber polymerization takes place at a temperature from 40 degrees to 50 degrees F. A coolant is supplied to each reactor to maintain this temperature. Sensing elements S, S', and P detect changes in the inlet and outlet coolant temperatures, and return pressure of coolant, respectively. Sensing elements FM detect coolant flow to each reactor.

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Real Time On Line Process for Continuous Polymerization of Styrene- Butadiene Latex

This computer controlled process is for emulsion polymerization of styrene- butadiene rubber. Shown is a cold rubber system. Raw materials. such as styrene, butadiene, etc., are fed into a reactor unit. Normally, such a unit consists of twelve kettle-type vessels with agitators. Cold rubber polymerization takes place at a temperature from 40 degrees to 50 degrees F. A coolant is supplied to each reactor to maintain this temperature. Sensing elements S, S', and P detect changes in the inlet and outlet coolant temperatures, and return pressure of coolant, respectively. Sensing elements FM detect coolant flow to each reactor.

The computer is programmed with a mathematical model of the emulsion polymerization process. During the process, data from sensing elements S, S', P, and FM is fed to the computer. The latter determines the reaction rates in each reactor and the amount of monomer conversion. This information is used in the mathematical model to project the monomer conversion and reaction rates into the future. The projection is made by calculating the fraction f of the contents of each reactor transferred to downstream reactors in a given time interval delta t based on equations for mixing in stirred vessels. Mixing in one stirred reactor with flow in and out at a rate F is described by f= e/-F deltat/v./ In this equation, f is the fraction of the original contents removed from the vessel of volume V in the time increment delta t.

For a series of N reactors, the fraction of the total original contents NV transferred downstream is given by

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For calculating future reaction rates, the following equation is used

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where R(n)/t+ deltat/ is the reaction rate computed for a future time increment delta t. The terms gamma n,m represent the volume of reactor m transferred to reactor n during the time delta t. The terms omega represent the correction term applied to the volume factors gamma n m for computing the reaction rate in n based on latex transferred from m. The omega terms represent the adjustment necessary to account for the effect of induction phenomena or tail-off of reaction rates at the end of the train due to decreased mass transfer efficiency, as well as correction for non-ideal mixing and consistent measurement errors. The omega's are computed by comparing the predicted to the changes which actually occur in the system.

The future monomer conversion is computed through incrementing the forward mixing process and polymer production at the future reaction rates in each reactor using the relationship

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In the second equation, W is the total weight of monomers in the reactor, converted and unconverted, based on the charge recipe and w(n) is the quantity of converted mo...