Project number:

PROJECT TITLE

Amine characterisation using molecular simulation

THESIS DIRECTOR Allan MACKIE e-mail: allan.mackie@urv.cat Tel. + 34 977 55 96 74

SUPERVISOR IFP Véronique LACHET e-mail: Veronique.LACHET@ifp.fr Tel. + 33 1 47 52 61 22

DESCRIPTION

Overview:

This project focuses on the development and application of molecular simulation techniques for the prediction of thermodynamic properties for systems of interest to the Chemical and Petroleum industries. Particular emphasis will be placed on the study of aqueous amine systems including the development of new intermolecular potentials and novel simulation methodologies. This is a collaborative project with the IFP and approximately half of the time will be spent at the IFP in Paris and half at the URV in Tarragona.

Background:

Aqueous amines are commonly used in many industrial processes developed for the treatment of natural gases. Researchers at the IFP have been working for several years on the development of “sweetening” technologies to remove CO2, H2S and impurities, such as COS, RSH and other sulphur compounds that are present in variable quantities in natural gases. These technologies are based on the absorption of these contaminants in chemical and/or physical solvents. The accurate knowledge of phase equilibrium as well as phase properties of the involved systems is essential for the correct sizing of the gas processing units. In the proposed work, these required properties will be studied using molecular simulation techniques. Equilibrium properties will be studied by Monte Carlo simulation, whereas transport properties will be assessed using molecular dynamics.

Research Group at the URV:

Research in our group centres on the development and application of theoretical and computer simulation techniques for the study of the properties of fluids and materials. Both molecular and mesoscopic models are used: the molecular-based models explicitly describe the main interactions between the constituents whereas the mesoscopic models use a coarse-grained approach. These models are used to predict the behaviour of fluids and materials at conditions which are difficult to access by experiments, as well as to gain a microscopic understanding of the fundamental processes at work. Areas of current interest include: the prediction of the thermodynamic and dynamic properties of fluids, self-assembly in surfactant solutions, drug delivery and controlled release, and the dynamics of mesoscopic systems.

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IFP:

The IFP is a world-class public-sector research and training centre, aimed at developing the technologies and materials of the future in the fields of energy, transport and the environment. It provides public players and industry with innovative solutions for a smooth transition to the energies and materials of tomorrow – more efficient, more economical, cleaner and sustainable. In this project, the student will interact with different researchers of the Thermodynamics and Molecular Simulation Department at the IFP. The department’s work primarily concerns the thermodynamic properties of fluids, adsorption phenomena and transport properties, together with a solid background in the development of molecular modelling tools and intermolecular force fields.

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Project Scope:

In recent years, significant progress has been made with methodologies that permit the calculation of properties from molecular based algorithms. Monte Carlo techniques such as the Gibbs ensemble and grand canonical ensemble with histogram rescaling permit the accurate prediction of thermodynamic properties such as phase equilibria. These methods have been successfully applied in order to predict the behaviour of alkane mixtures at temperatures and pressures typically found in oil reservoirs amongst other systems. We are currently involved, in collaboration with the French Petroleum institute (IFP), in the development of intermolecular potentials and simulation methodologies that permit the prediction of both thermodynamic and dynamic properties of industrially relevant systems. In particular, a set of models is being developed which is similar in spirit to the functional group contribution methods, but at the molecular scale, that allow the construction of any type of molecule out of a reduced set of basic units. For example, a model has been developed that allows aromatic molecules to be treated that has been shown to be successful for benzene, tolune and ortho, meta and para -xylene, styrene, naphthalene and anthracene.

The first step of the proposed work will be the development of an accurate transferable intermolecular potential required to study the thermo-physical properties of different amine molecules. These developments will be carried out for standard primary, secondary and tertiary amines, and also for more complex amines baring other polar groups like alkanolamines (MEA, DEA, MDEA...). The different properties that will be studied during this work include vapour pressures, heat capacities, densities, viscosities and critical coordinates. Properties of new solvents developed in IFP projects could also be calculated using the proposed potential for amines.

The second step of the proposed work will be devoted to the study of water-amine and gas-water-amine mixture properties. This work program will imply substantial methodological developments in order to accurately model the hydrogen bonding that can occur between water and amine molecules and also to take into account possible chemical reactions in the system (protonation of amines for instance). A generalization of the Reaction Ensemble recently implemented in the GIBBS simulation code will be undertaken in order to extend its application to flexible molecules. Transport properties of these mixtures will also be studied. Among others, the diffusion coefficients of different gases (CH4, CO2, H2S, O2, N2, Ar) in amine solvents will be calculated using molecular dynamics.

If successful, this work will allow predictions for properties to be made for a wide range of important compounds which have up to now been unreachable for simulation techniques. These predictions will be of importance in the design and optimisation of current chemical processes based on theses mixtures as well as in the creation of novel alternatives.

The Ideal Candidate:

The candidate should preferably have an engineering or physical science degree and be prepared to be involved in large scale numerical calculations along with algorithm and theoretical development. Candidates should preferrably hold a Master's degree, or have an official title enabling them to start a Ph.D. in their country of origin, with a minimum of 300 ECTS credits of higher education

Prospectives after Graduation:

At the end of the PhD, the student will have acquired expertise in molecular modelling techniques and in particular Monte Carlo and molecular dynamics simulation as well as in algorithm and computer code development. The candidate will then be well suited to enter both into industrial research and development departments as well as initiating research work in an academic framework.