gO:CFD — the gPROMS^® Object for CFD

An overview

Typical uses of gO:CFD are to:

predict product quality and yield accurately over a wide range of operation
improve yield and throughput
troubleshoot poor operation
identify reactor hotspot locations accurately and determine corrective action
define safe operating envelope for complex reactions
optimise equipment sizes and reduce design margins with confidence
determine control structures and settings based on accurate performance prediction

In contrast with previous approaches for linking CFD and process modelling systems, gO:CFD^®; provides an "off-the-shelf" capability for achieving the benefits from combining the two technologies.

The gPROMS Object for CFD (gO:CFD) is a unique and powerful tool that enables reaction engineers to combine the power of Computational Fluid Dynamics (CFD) packages for fluid flow and mixing modelling with gPROMS' capabilities for modelling of complex reaction systems.

The two technologies are highly complementary. Each has well-developed features for dealing with key phenomena taking place in reactive systems.

Currently-supported CFD packages are Fluent Inc.'s Fluent^® and CD Adapco's STAR-CD^®.

Capability	CFD	gPROMS
Detailed treatment of fluid mechanics and mixing	Yes
Solving equations in irregular geometries	Yes
Handling very large systems of equations	Yes	Yes
Multi-component phase equilibria		Yes
Detailed modelling of multi-component mass transfer		Yes
Modelling complex reaction schemes including equilibrium reactions		Yes
Capability to model other complex phenomena		Yes

By combining the best of these features, the reaction engineer is able to model reaction systems with an unprecedented level of accuracy, providing detailed quantitative information for reactor design, troubleshooting and operational decision support.

Key features and benefits

Reaction models are implemented in the gPROMS modelling language, capturing reaction chemistry knowledge in a maintainable and extendible form that can be used throughout the process model lifecycle.
Kinetic and other model parameters can be determined accurately using gPROMS' parameter estimation capabilities before the model is linked to the CFD package.
gO:CFD allows you to extend your CFD models with detailed modelling of reactions - including implicit sets of reaction equations and a variety of heterogeneous reactions - that are far more sophisticated and complex than those available via standard CFD reaction facilities.
A full range of reactions can be modelled wherever they occur - on the catalyst particles, within the laminar film surrounding the particles, or within the bulk fluid.

How gO:CFD works

gO:CFD links a gPROMS model (prepared and tested in the gPROMS ModelBuilder environment) of reaction kinetics and other physical and chemical phenomena to each CFD cell.

See the brochure "Heterogeneous catalytic reaction applications" for further examples:

gO:CFD applied to Fluent
gO:CFD applied to STAR-CD

This ensures that the gPROMS reaction calculation takes into account the spatial variations in species concentrations and temperature determined by the CFD calculations. In turn, the CFD mass and energy conservation equations take into account the rates of generation or consumption of species, as well as the rate of heat generation resulting from the reactions.

The state-of-the art architecture of the gPROMS Server and gPROMS' advanced mathematical solution methods ensure that gO:CFD achieves remarkable computational efficiency despite the complexity of the underlying calculations.

gO:CFD reaction models

gO:CFD is supplied with four different reaction model templates: gO:CFD for various reaction types

Homogeneous equilibrium and non-equilibrium reactions occurring in a homogeneous fluid comprising a number of chemical species. Where applicable, gO:CFD automatically exploits chemical reaction equilibrium relations in order to reduce model size.
Heterogeneous catalytic reactions occurring at the catalyst surface, with mass and heat transfer limitations in the laminar layer surrounding the catalyst particle in turbulent fluid.
Heterogeneous catalytic reactions occurring at the catalyst surface, with non-catalytic reactions occurring both in the laminar layer and in the bulk of the fluid.
Heterogeneous reactions with dissolving particles of one of reactants, with reactions occurring both in the laminar layer and in the bulk of the fluid.
Surface chemistry for catalytically-active surfaces such as catalyst-coated wires or monolith reactors.

All of the heterogeneous reaction models include detailed descriptions of mass and heat transfer phenomena based on the Maxwell-Stefan formulation for multi-component systems. This accurately models the resistances that limit the reaction rate, as well as the potentially significant differences in temperature and reactant concentrations between the particle surface and the bulk fluid.

Licensing

gO:CFD is licensed as a separate PSE product. A gPROMS ModelBuilder licence is required to build a customised gPROMS reaction model from one of the provided templates.

Prerequisites are:

a gPROMS ModelBuilder licence for creating reaction models
Fluent Inc.'s Fluent v. 6.2.16 or later, or
CD adapco's STAR-CD v. 3.15 or later

See supported platforms for availability.

PSE ModelCare

Through our ModelCare consulting service, PSE can also provide expert assistance in building sophisticated linked CFD-gPROMS models of reaction systems, as well as in the general use of process modelling in optimising process design and operation.

ModelCare is specifically designed to help you or your specialists to implement robust, detailed models in the minimum of time, while ensuring a handover of technology to your organisation to build a strong modelling capability for the future.

gO:CFD — the gPROMS® Object for CFD