Molecular modeling and process simulation: Real possibilities and challenges (original) (raw)

Molecular-Modeling Methods and Use for Product and Process Design

Significant progress has been made in recent years on development of molecularly based methods for accurate prediction of chemical and physical properties relevant for product and process design. A number of ideal-gas properties are routinely predictable. However, despite progress in computing hardware and simulation methodologies, prediction of condensed-phase properties of interest to industrial applications is not currently practiced on a routine basis. Present status of theory, molecular models, and industrial practice will be described. Molecular simulation refers to computational statistical mechanics based on force fields. Most existing force fields have been optimized to the configurational properties of isolated molecules and thermodynamic or structural properties of liquids near room temperature. Recently developed force fields have become available that also reproduce phase coexistence properties and critical parameters for selected systems, but they are not yet generally applicable to many systems of interest. Simulation methodologies for rapid determination of intermolecular potential parameters from experimental data are discussed. Two key unresolved questions remain, namely how to incorporate polarizability and other non-additive interactions, and the logistics of large-scale efforts to obtain parameters for broad classes of components. Computational quantum chemistry does not require predetermined force fields. Instead, it predicts energy and related properties from the nuclear (geometric) structure and the electronic orbital structure using the Schrödinger equation. Solution time and storage requirements increase rapidly with the number of atoms, but high accuracy can be achieved. At present, most results are for the zero-K, isolated-molecule (ideal-gas) case, but methods are advancing rapidly, including for solvation.

Chemical process modelling from a micro to a macro approach: Closing the gap

Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales

The present study discusses the multiscale modeling of chemical processes. Despite the existence of very good models for chemical processes from a macroscopic point of view, they can be limited due to the use of poorly estimated transport and transfer coefficients that reduce the accuracy needed for good technology development. Even if models are supported by fundamental relations, there is an unclear connection between their transport coefficient and molecular dynamics. The microscopic models can model several phenomena at atomic or molecular sizes with extreme precision. However, creating a link between the micro and the macro scale takes a huge computation time, as the way they link is not direct. We study this in detail here.

On industrial applications of molecular simulations

Molecular Simulation, 2020

Specific applications of molecular simulations, referred to as molecular-understanding-driven simulations, are exemplified by considering three industrial processes: needleless electrospinning and two membrane separations, one of a racemic mixture and the other of flue gas. Simulation setups for one and the same process are not unique and differences in the setups of such simulations are discussed with respect to properties in focus, results and general goals. Valuable information need not be obtained only from numerical values of some physical quantities but also from qualitative relations between various quantities; understanding of the process at the molecular level may be obtained even only from a visualisation of the system evolution. A novel version of the volume-control molecular dynamics simulation driven by the pressure gradient is proposed and tested.

A molecular-based equation of state for process engineering

2005

We outline here some of the steps we are taking towards the development of reliable tools for quantitative predictions of thermodynamic properties of complex fluids with equations based on statistical mechanics. The long term objective is to provide a userfriendly computer code and a wide database of molecular parameters for different compounds, able to be implemented in a process simulator. We have observed that the keys of the success when using molecular modelling tools for predictions rely on the selection of the appropriate model, representative of the molecular structure, and the use of physically meaningful molecular parameters.

A Modeling Framework for Chemical Process Design Through a Computer-Aided System

2004

This paper deals with a modeling environment for systematic chemical process design through a Computer-Aided Modeling System (CAMS), whose potential is highlighted through a case study. In particular, the capability of ICAS-MoT (an integrated modeling environment) to build, analyze, manipulate, solve and visualize mathematical models is shown. Our main interest is to use models for process design and analysis by testing and implementing them as fast as possible (in a reliable and efficient manner), writing the model equations without any programming effort, generating modules that can be exported through a model transfer feature to other simulation engines and/or external software, and implementing several process/model configurations in the same environment. From the application perspective, the modeling, operational analysis and process configuration of an emulsion polymerization reactor is considered. The case study highlights the advantages of using a computer-aided modeling sys...

MANUFACTURING CAPABILITY OF MATHEMATICAL MODELING OF CHEMICAL PROCESSES

Processes of petrochemistry and oil-refining, 2016

An overview about the modern state of mathematical modeling and optimization of chemical-engineering systems was given. An explanation to the concept “computer chemistry” was supplied and using in chemical structures identification. Chemical processes software is based on programs such as InvensysProcessSystems, AspenTechnologies, ChemStations. AspenPlus и HYSYS, Chemcad which permit not only occurring computing on high level, but also transfer from laboratory experiment to industry adoption of processes on basis of database of physicochemical equation and chemically pure products.

The triplet “molecular processes–product–process” engineering: the future of chemical engineering ?

Chemical Engineering Science, 2002

Today chemical engineering has to answer to the changing needs of the chemical and related process industries and to meet the market demands. Being a key to survival in globalization of trade and competition, the evolution of chemical engineering is thus necessary. Its ability to cope with the scientiÿc and technological problems encountered will be appraised in this paper. To satisfy both the markets requirements for speciÿc end-use properties of products and the social and environmental constraints of the industrial-scale processes, it is shown that a necessary progress is coming via a multidisciplinary and a time and length multiscale approach. This will be obtained due to breakthroughs in molecular modelling, scientiÿc instrumentation and related signal processing and powerful computational tools. For the future of chemical engineering four main objectives are concerned: (a) to increase productivity and selectivity through intelligent operations via intensiÿcation and multiscale control of processes; (b) to design novel equipment based on scientiÿc principles and new methods of production: process intensiÿcation; (c) to extend chemical engineering methodology to product focussed engineering, i.e. manufacturing and synthesizing end-use properties required by the customer, which needs a triplet "molecular processes-product-process" engineering; (d) to implement multiscale application of computational chemical engineering modelling and simulation to real-life situations, from the molecular scale to the overall complex production scale.