Short overview of the case

Innovative PAT-based control will be validated on a polymerization reaction using an existing process equipment container, which has been developed within the F³ Factory Project. The model reaction will be a poly-esterification reaction of a poly-acid and a polyalcohol provided by COATEX.

CS2

The quality of the polymer is defined by the length of the polymer chains (molecular weight), the residual unreacted monomer, cross-linked by-products and the ratio of the polymer end-groups. The stoichiometry between the reactants, the catalyst amount, the residence time and the degassing of water are parameters to be accurately controlled to obtain a high quality polymer. The stoichiometry, the end-groups and residual monomers and the viscosity derivation given by cross-linked by-products will be measured in-line or at-line by existing sensors. Rheological properties will be measured in-line by an innovative ultrasound sensor, which is developed by TNO and KROHNE in WP1.
Innovative PAT-based control developed by TUDO will be demonstrated on this reaction. TUDO will also validate the developed sensing and control solutions for the initial stage of the polymerization of water-soluble polymers in continuous pilot-scale equipment in cooperation with SOLVAY.

Which technologies will be validated

  • Novel rheology sensor based on ultrasound technologies
  • Combined use with existing on-line sensors (NIR, pH, …)
  • Novel self-adapting control method based on semi-rigorous models (nonlinear model-based predictive control)
  • Tool for an integrated approach for data mining and performance monitoring
  • Design evaluation of the overall system using realistic production scenarios based on dynamic models and co-simulation

What is the added value to switch from batch to the continuous process

In contrast to the traditional batch process the use of a continuous process reduces the down time of the equipment (therefore maximized throughput, lower/faster cleaning process, reduced energy consumption, enhanced and more narrow distribution of product qualities, etc. …). It will also increase the quality of the products by a direct link between the raw materials management and the final rheology control of the product allowing plant operation for a significant amount of time under controlled conditions. Additionally, running the process under stable parameters reduces the energy amount needed to operate the process at a specified operation point.

Expected achievements of the case

We want to achieve the following:

  • Establish an on-line control flow between the raw material addition to the final polymer properties
  • Reduce waste generated by cleaning of the reactor
  • Reduce the polymers out-of-specification by controlling the derivation of product quality parameters and the beginning of the synthesis of by-products
  • Increase capacity by 20%
  • Increase the robustness of process control to keep always the desired product quality level

First year achievements

Case Study 2 is related to the validation of PAT-based control for an intensified continuous production of a high-viscous polymer. The joined development of a new rheology sensor with control and monitoring tools based also on all the measurements techniques already available will allow to monitor the reaction and avoid degradation problems which can lead to a complete plugging of the reactor. The degradation of the product generates high molecular weight species which disturbs the rheology curves (figures 1 and 2).

2.1Figure1 Possible behaviors of the reaction

2.2Figure2 Rheology corresponding to different degradation

2.3Figure3 Kneader blades of the reactor

Preliminary studies and technical meetings between the involved project partners allowed clarifying the Case Study conditions and targets. The validation of the technologies will be carried out under various working conditions on a modular production plant at pilot scale. Its core component is a kneader reactor which is a kind of tubular reactor with two rotating shafts that are equipped with kneader blades (see figure 3). A preliminary trial will be done in the 2nd quarter 2016 without the new sensor to optimize the process parameters. The development of the sensor is done at TNO in parallel.