A 2‐D observer to estimate the reaction rate in a stopped flow fixed bed reactor for gas phase olefin polymerization

Abstract

A two-dimensional high gain observer has been constructed to estimate the reaction rate parameters in a laboratory scale stopped flow fixed bed reactor for gas phase ethylene polymerization. The observer is based on the heat balances of a validated model of the reactor and the measured variable is the outlet temperature of the fixed bed. To create an observable system of equations, the polymerization rate is considered in two parts, an activation energy term and a lumped parameter. The effective radial conductivity in the fixed bed and the heat-transfer coefficient at the wall are considered separately. The polymerization rate is calculated from the observer results and is in good agreement with the measured data and calculated values.

Polymerization of ethylene in the gas phase—A new combined hardware and software tool

“…All reactors were pressurized with nitrogen for 20 s to avoid compression heat effects when initiating the monomer flow. It was observed by Browning et al [20,21] that if the pressure in a small reactor was instantaneously increased from 1-7 bars, the temperature of the gas in the reactor increased. The polymerization is launched by opening the monomer flow to the system once thermal equilibrium has been reached.…”

“…However, a detailed modelling study later showed that despite the redesign, there was a possibility of encountering non-negligible temperature gradients inside the reactor despite its small volume. [20,21] Finally, this set-up was not adapted to inject components that are liquid at room temperature (e.g., comonomers and alkanes used in condensed mode operation).…”