Advanced Process Modelling for separation systems

Bringing new accuracy and sophistication to separation modelling

Vapour-liquid, liquid-liquid and solid-liquid separation are fundamental processes in the Chemical Process Industries. Distillation operations alone are estimated to be responsible for some 40% of energy usage.

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

gPROMS ProcessBuilder provides advanced modelling capabilities for many different types of separation process, allowing true optimisation of separation facilities with potential savings of millions of dollars.

Typical application areas

ProcessBuilder brings the world's most sophisticated modelling and optimisation capabilities to many different types of separation processes, to help achieve optimal design and operation:

Distillation and absorption

gPROMS ProcessBuilder's fluid-fluid separation libraries provides extensive capabilities for high-accuracy modelling of conventional tray-by-tray or packed distillation columns and absorbers, as well as rate-based non-equilibrium column modelling.

Pressure-swing adsorption (PSA)

The power of the gPROMS environment allows easy solution of complex inherently-dynamic separation processes such as pressure-swing adsorption, for example to determine cycle steady-state. Self-interacting bed models help speed up calculation.

Rate-based separation

The standard ProcessBuilder fluid-fluid separation libraries provide 1-D rate-based models suitable for many distillation and absorption applications. The AML:GLC provides high-fidelity 2-film theory models capable of representing virtually any configuraton of separation device to a high degree of accuracy.

Novel separation equipment

The combination of ProcessBuilder library (including AML:GLC) models and custom modelling capabilities allows you to design virtually any type of separation equipment – Petlyuk columns, partition and divided wall columns, heat-integrated distillation columns (HIDiC), multitubular separation equipment.

Reactive distillation

The AML:GLC caters for reactive distillation and absorption in both tray and packed columns. It is possible to model reaction in the liquid bulk phase and both liquid and vapour films, to provide the highest possible accuracy for both steady-state and transient operation.

Heat-integrated distillation (HIDiC)

Heat-Integrated Distillation Columns (HIDiCs) represent a major breakthrough in energy efficiency, with savings of up to 50% possible. The ProcessBuider AML:GLC is the only commercial tool capable of modelling the complex heat transfer and non-equilibrium operations involved.

Membrane separation

ProcessBuilder's membrane separation library provides capabilities unique within flowsheeting tools. Membrane separation can be combined with other separation devices to perform analysis of novel separation systems, using the optimiser to select between alternative configurations.

Falling-film equipment

Falling film evaporators, condensers and reactors involve heat and mass transfer over a continuous transfer surface, within a tightly-defined operating envelope. gPROMS deals easily with the complex interaction of hydrodynamics, heat and mass transfer and reaction kinetics. PSE can supply models on request.

Crystallization processes

PSE's gCRYSTAL environment provides state-of-the-art crystallization process modelling for optimisation of batch and continuous crystallization process design and operation based on high-fidelity models.

Solids separation processes

PSE's gSOLIDS environment provides screens, dryers, centrifuge, cyclone and state-of-the-art solids-vapour and solids-liquid separation models for optimisation of batch and continuous solids process design and operation.

Optimisation and other key technologies

While it is essential to be able to represent separation process accurately for effective design, the true value of model-based design and operation comes from the ability to optimise configuration and operating conditions.

The gPROMS platform's extensive optimisation capabilities make it possible to seek optimal values for design variables and operating conditions directly rather than simply performing manual trial-and-error simulation.

Optimal column configuration

gPROMS's mixed-integer optimisation (MIO) capabilities can be used to optimise the number of column stages and feed and draw tray locations simultaneously with other typical design and operational parameters, to arrive at truly optimal separation section design.

Optimising separation sections

The gPROMS optimisers can easily handle optimisation of large integrated flowsheets involving tens of discrete and continuous decision variables as part of a plant-wide optimisation. This makes possible truly optimal process design and operation, with potential benefits of millions of dollars per year.

Handling of complex recycles

ProcessBuilder has sophisticated facilities for rapid and robust convergence of flowsheets with multiple interacting mass and energy recycles. Solution times of seconds rather than hours open the door to rapid sensitivity analysis and true optimisation of processes such as air separation units (ASUs) for the first time.

Parameter estimation

Unlike vapour-liquid separation, where the physical properties package usually provides accurate thermodynamic data, in processes such as crystallization it is often necessary to estimate kinetic (e.g. growth) parameters from experimental data. gPROMS's extensive parameter estimation capabilities make it possible to create truly predictive models.

PSE tools and capabilities

PSE brings a powerful combination of state-of-the-art tools and expert services to engineers and operations personnel working with separation systems:

ProcessBuilder separation libraries

ProcessBuilder's sophisticated separation libraries represent the state-of-the-art in modelling of fluid-fluid separation systems for standard flowsheeting applications.

AML for Gas-Liquid Contactors

ProcessBuilder's AML:GLC provides rate-based modelling capabilities for representing virtually any separation operation to a high degree of accuracy, including novel configurations such as partition, divided wall or Petlyuk distillation.


gCRYSTAL provides comprehensive facilities for optimising batch and continuous crystallization process design and operation.


gSOLIDS is a flowsheeting environment for design and operational analysis of batch and continuous solids processes.

gSAFT advanced thermodynamics

In addition to standard physical properties options, ProcessBuilder's gSAFT advanced themodynamics option provides a next-generation tool for accurate prediction of pure component and mixture data for non-ideal components such as electrolytes and polymers.

PSE Consulting

PSE provides expert ModelCare assistance and full turnkey consulting services to help apply the technologies and approaches described above rapidly and effectively.

PSE also has an extensive set of models that can be supplied under ModelCare agreements, for applications such as full dynamic hydraulic modelling for tray-to-tray columns (as applied in PSE's analysis of the Texas City Refinery accident [report; 15MB download]).

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