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 Process provides advanced modelling capabilities for many different types of separation process, allowing true optimization of separation facilities with potential savings of millions of dollars.
Typical application areas
gPROMS Process brings the world’s most sophisticated modelling and optimization capabilities to many different types of separation processes, to help achieve optimal design and operation:
Distillation and absorption
gPROMS Process’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.
The standard gPROMS Process 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 gPROMS Process 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.
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 gPROMS Process AML:GLC is the only commercial tool capable of modelling the complex heat transfer and non-equilibrium operations involved.
gPROMS Process’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 optimizer to select between alternative configurations.
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.
Optimization 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 optimize configuration and operating conditions.
The gPROMS platform’s extensive optimization 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 optimization (MIO) capabilities can be used to optimize 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.
Optimizing separation sections
The gPROMS optimizers can easily handle optimization of large integrated flowsheets involving tens of discrete and continuous decision variables as part of a plant-wide optimization. This makes possible truly optimal process design and operation, with potential benefits of millions of dollars per year.
Handling of complex recycles
gPROMS Process 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 optimization of processes such as air separation units (ASUs) for the first time.
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:
gPROMS Process separation libraries
gPROMS Process’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
gPROMS Process’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.
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]).