Master Thesis (theoretical) Modeling the Storage Stability of Stabilized Monomers at Various Temperatures
Joint project of divisions 2.2 Process Simulation and 2.3 Classification of Hazardous Substances and Dangerous Goods, Bundesanstalt für Materialforschung und -prüfung (BAM)
Polymers are a ubiquitous part of everyday life. Their precursors are reactive, thermally unstable monomers, also known as polymerizing substances (PS). PS can polymerize with a significant release of heat and can therefore pose a considerable safety hazard during storage and transport (by road or sea). Insufficient heat dissipation can lead to self-heating and, in the worst case, trigger a runaway polymerization and thermal explosion. This was the case in the 2012 accident on the cargo ship “Flaminia” and the “Stolt Groenland” in 2019, as well as in several tank failures in Japan (2012) and Taiwan (2001).
For this reason, reactive monomers are stabilized during storage and transport to prevent unwanted polymerization. For acrylic monomers, inhibitors such as hydroquinone monomethyl ether (MeHQ) are commonly used, whose stabilizing effect depends on the presence of dissolved oxygen. In storage tanks, oxygen is provided by the gas headspace above the liquid, from which it dissolves into the liquid and diffuses. Due to mass transport limitations and the simultaneous consumption of oxygen by the inhibition reactions, local oxygen-deficient regions may form, reducing the effectiveness of the stabilization system and allowing polymerization to proceed.
The objective of the thesis is to develop a dynamic model of a storage tank containing stabilized acrylic monomers that is suitable for analysis of storage stability at different storage temperatures and vessel volumes. Additional factors such as headspace volume, headspace O₂ content, and stabilizer concentration should also be investigated. The model should include the relevant reaction kinetics as well as description of the mass and heat transport processes. A central task will be to determine an appropriate modeling depth and to assess whether a reduced kinetic description is sufficient or whether a more detailed polymerization model is necessary to predict the end of the inhibition period and onset of polymerization. Values for the required kinetic, thermodynamic, and transport parameters will need to be obtained from literature and available experimental data or, where necessary, estimated.
Task Description:
- Literature review of the inhibition and polymerization kinetics of stabilized acrylic monomers, with particular focus on the role of oxygen
- Determination of an appropriate modeling depth suitable for storage stability analysis
- Development of a dynamic storage tank model including relevant reaction kinetics and description of mass and heat transport
- Identification and compilation of the required kinetic, thermodynamic, and transport parameters from literature and available experimental data
- Investigation of the influence of storage temperature, vessel volume, headspace conditions, and stabilizer concentration on storage stability
- Sensitivity analysis of important and uncertain model parameters
Desirable Knowledge and Skills:
- Pursuing a degree in chemical engineering, process engineering, or a related field
- Knowledge of process modeling, thermodynamics, and reaction engineering
- Understanding of reaction kinetics and heat and mass transfer
- Programming experience in Python; experience with C/C++ is advantageous but not required
- Interest in modeling and numerical simulation
Start:
Immediately
Compensation:
Please note that no financial compensation can be offered for this work.
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