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Advanced Process Modelling for separation systems

New accuracy for distillation and absorption modelling

"With gPROMS we made remarkable progress compared to the tools that we used in the past".

- Linde Engineering,
following a three-month evaluation

     AML Gas-liquid contactors

Distillation and absorption are fundamental processes in the Chemical Process Industries.

Despite this, the modelling of separation processes remains relatively unsophisticated, and is not well catered for by commercial simulation software.

Most current modelling of distillation and absorption equipment assumes equilibrium between phases; virtually all modelling is steady-state; there is little software available that caters for less-conventional configurations such as reactive distillation and absorption and heat-integrated columns; and there is little formal optimisation within a flowsheeting environment.

Even the selection of feed and side draw locations is usually done on a trial and error basis.

PSE brings a powerful combination of state-of-the-art tools and expert services to the market:

Collectively these overcome all of the deficiencies described above, to provide high-accuracy predictive models for all types of vapour-liquid separation.

The gPROMS advantage

gPROMS is not just a distillation modelling package. It is a complete process modelling environment that allows the construction and execution of high-accuracy first-principles models within a flowsheeting and optimisation framework.

Some of these capabilities are shown in the diagram below.

gPROMS' combination of capabilities provides unprecedented modelling power for designers of distillation and absorption equipment.

gPROMS capabilities explained

gPROMS provides many advantages over most other distillation modelling software . Here are a few:

 

 

 

 

 

gPROMS modelling power

gPROMS is a general-purpose modelling framework that provides capabilities for modelling of any distillation system to any degree of accuracy, in steady-state or dynamic mode.

gPROMS' open architecture also means that you can incorporate any physical properties package or other external calculation into your model.

Advanced Model Library for Gas-Liquid Contactors (AML:GLC)

The gPROMS AML:GLC is a library of high-fidelity, non-equilibrium component models for gas-liquid separation.

It is designed to cover a wide range of separation operations, including conventional packed columns for distillation, absorption and evaporation, and more complex units such as heat-integrated devices, dephlegmators and falling-film columns.

The library is supplied in 'open model' form to allow you to customise models easily.

Maxwell-Stefan multicomponent diffusion

The AML:GLC models use Maxwell-Stefan multicomponent diffusion models to provide ultimate rate-based accuracy for mass transfer.

This means that operating envelopes can be quantified accurately, and design margins reduced. PSE's implementation caters for fast reaction, including ionic reaction, in the liquid bulk and film and vapour film.

Flowsheeting

Unlike many specialist distillation tools, gPROMS allows you to work with distillation columns in a flowsheeting context. This means that:

Optimisation

It is possible to rigorously determine optimal location of feed and draw trays, or to choose the optimal control scheme from a number of alternatives, using gPROMS' Mixed-Integer Optimisation (MIO) capability.

You can also use the standard steady-state and dynamic optimisation capabilities for optimising – for example – column diameter or heating and cooling start-up trajectories.

 

Export of models to other environments

Once you have a high-accuracy column model in gPROMS, you can use the gPROMS Objects to execute it within other software environments.

For example, gO:MATLAB and gO:Simulink enable execution within MATLABŪ and SimulinkŪ respectively (it is also possible to execute Simulink controllers within gPROMS); gO:CAPE-OPEN executes gPROMS models within CAPE-OPEN compliant flowsheeting packages.

You can also use gO:RUN to provide the model via an MS Excel or other custom interface to non-modelling personnel such as plant operators.