Advancing process understanding

Our flagship product; VMGSim is a world-class, rigorous and comprehensive steady-state process simulator developed with an integrated flowsheet design in a user-friendly, modern environment.


Providing unparalleled model sophistication and precision

VMGSim is used around the world to model existing processes and to design new facilities from the ground up.

With over 20,000 chemicals, more than 80 thermodynamic property packages and hundreds of unit operations, VMGSim provides unparalleled model sophistication and precision, giving you more time to solve processing challenges creatively.

As a result, you'll find innovative ways to increase the value of your product while reducing your operating costs and wasted material.

Let VMGSim be like your own engineering advisor: propagating information, anticipating your questions, and suggesting effective methods for model development and exploration.

Better still, it builds your models based on rigorous thermodynamic relationships and needs only the information absolutely required to do so, saving you time and processing power.

Real-time process calculations

Experiment with different equipment configurations in your simulation models to see the effects of changes to the whole system instantly and economically.

VMGSim does this by instantly calculating process changes, intelligently propagating information, and continually monitoring degrees of freedom when you modify any unit operation parameters or process conditions.

Bi-directional information propagation

Model your plants using a relatively small number of inputs because VMGSim can extract only the most useful information from your data. That information is then spread throughout your flowsheet automatically, allowing you to develop creative solutions to extremely difficult problems you may not be able to easily solve using traditional sequential simulators.

VMGSim tracks all of your data inputs, making it possible to immediately see what was added to the system and the result. The bi-directional information propagation capability also eliminates the need for artificial recycle blocks and simultaneous convergence of recycles and controllers throughout your flowsheet.

Automatic degrees of freedom monitoring

VMGSim is a true Gibbs-based simulator that is capable of monitoring each variable’s state and its thermodynamic significance. By means of the Gibbs phase rule, with enough degrees of freedom fulfilled, calculations are automatically completed and the results transmitted throughout your flowsheet. 

Simulations are automatically recalculated every time you change the value of a variable without the need for special estimates. You can now concentrate on understanding your process while VMGSim handles the math.


Accurate, robust, and cost effective process simulation solutions to predict the detailed behaviour of your process units and plants.


Inspiring confidence and increasing profitability

Whether you are designing new process units, optimizing, revamping or troubleshooting, Symmetry helps you improve your operating efficiency and product quality, while reducing your overall capital and operating costs.

With Symmetry as your reliable partner in modelling your entire process units, you'll have the confidence of knowing your plant is operating safer and at a higher profit than ever before.

Boost your productivity quickly and easily

Symmetry uses the interactive calculation principles of non-sequential, unit operation calculations with partial data flow developed in the late 1970s by Craig Morris. These concepts combined with Symmetry’s state of the art graphical user interface provides you with the fastest, most intuitive ways to develop and evaluate process models.

Easily and seamlessly simulate important industrial processes such as natural gas sweetening using amines and physical solvents, Claus plants, and tail gas treatment without special workarounds or awkward unit operation combinations.

A true partner

Symmetry behaves like you do, making the most of whatever information you have available while using the rigorous boundaries provided by chemical engineering science and thermodynamics.

It helps you not only set up your simulation but it can perform complex information checking in the background. So now information is propagated through the flowsheet instantly and calculations performed whenever possible.

After using Symmetry for a few days you'll be amazed at how quickly and easily you've increased your productivity.

A commitment to quality and innovative design

Windows and workflows are carefully designed with the expert and novice in mind. Specialized unit operations allow you to quickly build complex flowsheets that closely resemble your plant.

Symmetry handles the solution and convergence of complex flowsheets elegantly and consistently, allowing you to work in an environment that you can understand.

We pride ourselves on the fact that Symmetry is built on the bedrock provided by VMGThermo and a decade of development and validation of thermodynamic models used from online monitoring applications, dynamic simulation, to heat exchanger design.

Our goal is to free your imagination and allow you to be as productive as possible, today, tomorrow and beyond.

Simulations are only as good as their underlying thermodynamic model


Every day we develop and work on thermodynamics, physical properties, and flash calculations, ensuring the foundation of all our simulations is second to none.

We develop and implement our models, determine our own interaction parameters, and work with the best providers of physical property data to provide you the very best models that are validated using the best possible data.

Decades of experience, research and development in applied thermodynamics are captured in VMGThermo.

VMGThermo is an extremely comprehensive property package engine which includes support for chemically reactive systems, oil and rigorous multiphase flash, combined with extensive selection of equations of state and activity coefficient models.

It includes a comprehensive pure component database with more than 20,000 pure components developed based on evaluated data from the National Institute of Standards and Technology Thermodynamics Research Center.

It's the engine under the hood of Symmetry and widely used as a plug-in engine by many well-known third-party on-line and off-line applications, such as: 

  • HTRI’s Xchanger Suite
  • NEOTEC’s pipeline simulation products
  • Ariel Corporations Compressor
  • Farris’s iPrism
  • Berwanger’s PPM
  • IDEAS’s Operator Training and Dynamic Simulation

This ensures that our thermodynamic calculations are put under extraordinary stress and provide quality results for conditions and expectations well beyond process simulation.

Learn more about VMGThermo

  • Carefully validated property packages for natural gas, refining, chemical and special processes such as amine sweetening, sulphur treating plants and power cycles.


  • Accurate CO2 freezing point, Hydrate calculations including inhibition using ethylene glycol and methanol.
  • Comprehensive Claus Property package


  • Comprehensive Amines Property package


  • Comprehensive Pure Component Library – 20,000+ pure components
  • Extensive collection of Equations of State and Activity models with consistent interaction parameters.
  • Built-in pure component and mixture parameter estimation
  • Extensive mixture interaction parameter database with data source references
  • Refinery Oil assay characterization and blending
  • Unparalleled coverage of physical properties - speed of sound, actual Cv, isothermal compressibility amongst many others


  • Symmetry offers a comprehensive suite of critically evaluated data for over 20,000 pure components and a mixture interaction parameter database of over 100,000 binary parameters – evaluated in-house and carefully tuned to our flash engine and pure component properties.



A powerful and accurate package for the characterizations of crude oils


You are given a comprehensive selection of distillation curve inter-conversion methods in volume, mass or mole, including TBP, D86, D1160, D1160 Vacuum, D2887, and the option to simply create a curve from a Carbon Number (Cn) analysis or bulk properties.

Also included in the assay description is a wide range of additional data: Density Curves, Molecular Weight Curves, and Viscosity Curves.

  • Input or back-calculate light-ends from the assay data
  • Match the bulk oil density, viscosity and thermal conductivity as a function of temperature
  • Multiple assays and multiple blends can be defined, managed, and used in a simulation case
  • Automatically reflect your changes to assays or blends in the simulation model, including automatic recycle convergence

Symmetry is a general process simulator and possesses a complete suite of process unit operations that can be configured to model virtually any process of interest in the Gas processing, Refining/Petrochemical or Chemical industries. 

Unit Operations Library

  • Distillation - rigorous, robust and fast two and three phase distillation including complex refinery configurations and heterogeneous azeotropic distillation.


  • Two- and Three-phase separators with multiple feeds and energy input
  • Mixers, Tees, Component  Splitters
  • Balances - Mole, Mass and Energy balance operations
  • Excel™ Embedded unit operations with fully featured spreadsheet, macros and Visual Basic for Applications
  • Pumps, compressors, expanders with option to input performance curves
  • Control valves and relief valves
  • Multiphase pipe operation
  • Shell and Tube and Air Cooler rating


  • Shell and Tube exchanger operation with rating using HTRI
  • Multi-stream heat exchangers


  • CSTR, Plug-Flow, Equilibrium, Gibbs and Stoichiometric Reactor models
  • Flowsheet Controllers and Sets
  • Liquid-Liquid extractor
  • Gas orifice
  • Ejector


An open model approach to help you understand your process simulations like never before


Track every stage of your model, giving you a level of detail and insight that’s unparalleled in process simulation software and removes the “black box” approach in refinery modelling.

Symmetry features powerful, easy-to-use and an accurate package for the characterization of crude oils, giving you the power to add more experimental data for more accurate models.

Get a comprehensive selection of distillation curve inter-conversion methods in volume, mass or mole, including:

  • TBP
  • D86
  • D1160
  • D1160 Vacuum
  • D2887


  • Create a curve from simple bulk properties
  • Include a range of additional data, such as density curves, molecular weight curves, and viscosity curves in your assay description
  • Match the bulk oil density, viscosity and thermal conductivity as a function of temperature.
  • Define, manage, and use multiple assays and multiple blends in your simulation case
  • See changes to assays or blends instantly, including automatic recycle convergence

The sulfur model available in Symmetry has been built based on rigorous thermodynamic model for the key species and the reactors offer a comprehensive set of options to take into account the kinetics of the reactions

Partnership with SRE

Sulfur Recovery Engineering is a company founded in 1998 in Calgary, Alberta. Since then, SRE has been performing on-site services to the sulfur recovery industry. The reaction furnace and Claus converter models available in Symmetry incorporate over 15 years of real, accumulated, field-data provided by SRE. In turn, SRE uses Symmetry to model their clients SRU's. Visit Sulfur Recovery Engineering.



  • Waste Heat Boiler
  • Catalytic Converter
  • Reheat Burner
  • Hydrogenation Reactor
  • Oxidation Reactor
  • Sulphur Condenser
  • Incinerator
  • Sx Properties
  • Air/O2 Ratio Calculator

Claus and tail-gas treating

Design, optimize, monitor, and troubleshoot sulfur plants with a complete set of unit operations.

These features are incorporated into the modern, user-friendly, and comprehensive core of Symmetry so that you can model your sulfur plants in a fully integrated flowsheet with acid gas treating units and general processing such as an entire refinery model.

VMG has also taken great care in capturing the best available data in the world to produce an accurate and validated property package and unit operations.


  • Phase Envelope – Temperature/Pressure (TP), Pressure/Enthalpy (PH), Pressure/Entropy (PS), Temperature/Enthalpy (TH) diagrams including calculation of critical point, hydrate curve and quality lines


  • Saturator - saturate a gas stream with water or any other component
  • Hydrate - calculate the hydrate temperature and pressure for two, three and four phase hydrates including inhibitors such as methanol and ethylene glycol
  • Special Properties for Natural Gas – calculate useful properties such as heating values, dew point, water dew point, Wobbe index, enthalpies of vaporization and pseudo-critical properties
  • Special Properties for Refining – Reid Vapour Pressure (RVP), flash point, pour point, viscosity, Research Octane Number (RON), Motor Octane Number (MON), refractive index


  • Property Table - generate plots and tables of physical properties for mixtures using configurable ranges


  • Distillation Curve  - generate boiling temperature assays for a given composition
  • XY Curve - generate XY diagrams for a given stream and key component at any pressure or temperature
  • Gibbs Curve  - generate Gibbs free energy of mixing curve for a given stream and key component at a pressure and temperature
  • Oxygen Calculator - determine excess O2 for a given reaction
  • Sulfur Detail – track key parameters in you Sulfur plant Sx, Dewpoint, H2S/SO2, etc.
  • Amine Detail - track key parameters in your amine model in the way you work and use them for setting flowsheet parameters such as rich to lean carbon dioxide and hydrogen sulphide loading


  • Material Balance – Easily generate an overall material and energy balance for the entire flowsheet
  • Psychometric Chart– determine or set humidity and relative humidity for a stream
  • Embedded Equipment Rating and Design Third Party Applications such as HTRI’s Xchanger Suite

Symmetry has a quick and robust column algorithm that is carefully tuned to reliably converge on complex refining distillation columns or reactive systems encountered in amine sweetening.

The tower supports 2 and 3 phase distillation and conveniently handles side strippers, pump arounds, heaters, coolers and multiple product and water draws.

The tower has a full range of specifications and trays that can be designed or rated.

Get a comprehensive system for modeling the removal of H2S and CO2 from your process streams


The system includes an extensive slate of chemical and physical solvents, an advanced tower model that incorporates mass transfer effects, along with a carefully validated electrolyte model that accurately predicts chemical and physical equilibrium.

The following solvents are supported:


  • MEA
  • DEA
  • MDEA
  • TEA
  • DIPA
  • AMP
  • DGA

Physical Solvents

  • Propylene Carbonate
  • NFM
  • NMP

Also supported are any number of mixed solvents and/or amines.

Rigorous dynamic simulation

The dynamic models share the same thermodynamics engine as steady state but use a dynamic network pressure-flow solver.

This permits the calculation of flowrates and pressures as a function of system parameters such as valve Cv, rather than using fixed, user-specified values.


You can tap into Symmetry’s programmable interface and drive simulations using COM compliant tools such as Excel, Visual Basic, C# and C++.

Using Symmetry as a plug-in simulation engine you can:

  • Develop your own user interface
  • Run embedded models for plant monitoring or optimization
  • Integrate custom calculations originally developed in Excel™ or other programming languages
  • Interface to databases and word processing programs


Take advantage of advanced Excel integration

Symmetry offers Excel™ as an embedded unit operation in the flowsheet, giving you spreadsheets that are fast and seamless, and running interactively with other unit operations in the model.

Workbooks can simply be added to the flowsheet quickly and easily as a standard unit operation. They can also freely exchange data within the model and can obtain data directly from DCS systems, data historians, or other programs.

Use Excel™, macros, and Visual Basic for Applications (VBA) to create custom applications using Symmetry’s COM Interface. Applications like this can bypass the use of the Symmetry GUI, which allows for increased speed and configuration flexibility, which is particularly useful for automation applications. Applications can be written using any COM compliant language available in the Microsoft Windows platform.

Real-time monitoring and optimization tools

Symmetry’s modern programming architecture and component structure makes it one of the easiest modeling systems to integrate with real time applications. We currently have advisory Symmetry models for plant supervisory applications and for profitability modeling running on-line in a variety of facilities including refineries and gas plants.

DCS Interface

Three different link configurations have been implemented successfully between Symmetry and a distributed control system (DCS). This is possible due to the object oriented structure of the Symmetry software, solver holding/triggering capabilities, and the available VSimCom COM interface to Symmetry.

The first option involves a direct connection between VSimCom and the DCS if an object linking and embedding (OLE) or COM interface is available within the DCS. The second option uses the Excel™ operation within Symmetry and the Excel add-in capabilities of a DCS if applicable. The last option has been to read/write Symmetry values from a OLE or COM compliant database, which is then accessed by the DCS as means of an indirect link.

Supported Databases

Symmetry’s modern architecture enables it to talk to just about any program imaginable, including databases of all types. Our users have developed a wide range of applications that read/write to databases such as Microsoft Access™ with relative ease. The modern architecture of Symmetry puts it at the top of the industry in terms of integration with other software applications.

No programming required

Get the convenience of using a professional spreadsheet directly inside Symmetry with Excel Unit Operations.

Simply drag the Excel icon from the unit operation palette to add Excel workbooks to the model. Select import/export to attach information from a stream or another unit operation to the worksheet.

The Excel operations will behave exactly like any other unit operation, triggering flowsheet calculations or reacting to changes in the flowsheet exactly like a native Symmetry unit operation.

Information is automatically recalculated and propagated without the need of cumbersome programming or specialized interfaces.

And there are no limits to the number of Excel worksheets you can have in a model.


Since you are working directly inside Microsoft Excel you have full access to Visual Basic for Applications (VBA) without the need of writing a single line of automation code.

If you are used to program spreadsheets using complex cell formulas and macros you can be immediately productive using Excel unit operations in Symmetry. Develop your own unit operation model such as a specialized reactor and integrate external data easily and consistently.

Save time with a fully integrated reporting system

Extract the most relevant information from your simulation and incorporate it into professional quality reports with Symmetry's fully integrated reporting system.

Project Report can automatically generate a detailed, fully customizable report template of your simulation.

The novel Summary Sets make it easy for you to select, collect, and display the most relevant information from your simulation in tabular format.


Get custom reporting with Excel

Add the Excel operation to the flowsheet and use it for custom reporting. One click will paste the connections of the model data into the spreadsheet in your personal format. These connections will update in the spreadsheet automatically from the model when changes are made.

Permanently built custom reports into your Symmetry cases and keep up to date in your preferred format with Excel's limitless formatting and multiple workbooks.

All numeric data and tables in Symmetry are copy-and-paste-enabled for information transfer to other Windows program.


Symmetry has a number of sizing and rating calculation tools including:

  • Vessel Sizing/Rating – Size two and three phase separators


  • Tray Sizing/Rating – Size or rate distillation trays with a number of methods and multiple designs per vessel
  • Relief Valve – Calculate the orifice area for a single or two phase relief valve given a set of inlet conditions


  • Gas Orifice Meter – Calculate orifice differential pressure value when given the pipe diameter, orifice diameter, gas flow rate and inlet process conditions, or alternatively calculate the flow rate when an orifice differential pressure is provided

Get a comprehensive set of interfaces and automation links to HTRI Xchanger Suite

Perform heat exchanger rating and design calculations directly from a Symmetry simulation model without manually transferring data or leaving the simulation model.

You can also embed rigorous exchanger simulations into a case, enabling rigorous prediction of exchanger output conditions and pressure drops in your models.

From any heat exchanger operation in your simulation model, you can access HTRI's rigorous exchanger design, rating, and simulation capabilities.

Clicking the live link will automatically connect the process model to the heat exchanger design program, propagating the required information, including physical properties and stream inlet and outlet conditions.

At any time, you may view and work in the heat exchanger program interface and the Symmetry interface. In addition to the rating, design, and simulation, the live links feature provides the option to create a separate input file for HTRI's Xchanger Suite and PSF files.


Process simulation models deliver benefits in all phases of engineering. From early process development and design, to engineering and production, these models may initially be simple and focus on phase behavior and material balances.

But as you gain or collect new information the model becomes more complete and with a better representation of reality.

Along this path, you increase process knowledge which leads to improved capital efficiency, engineering quality, and operational productivity.

With a unified modeling environment you are positioned to capture these benefits throughout the life cycle of your manufacturing plant.


The advanced functionality and powerful capabilities of Symmetry Refinery provides a comprehensive modeling solution to address the complex needs of our refining clients. Our technology allows users to fill gaps in their existing processes using our unprecedented, predictive modeling capabilities on a unit or enterprise-wide basis. This advanced technology also allows you to make use of any data from your production facility to be able to tune and refine your models. 

Symmetry Refinery is powered by our proprietary PIONA based molecular structure modeling (paraffins, iso-paraffins, olefins, naphthenes and aromatics) platform. This unique approach uses a chemical family structure-based characterization with a rigorous reactor basis designed to provide the framework for predictive modeling from a property estimation basis as well as being able to investigate the intricacies of reactor configuration details on the performance of the reactor unit. This allows for a single component slate to be used across multiple refinery units, both reactive and non-reactive, enabling multi-unit refinery evaluations. The combination of these leading edge models empowers the simulation of complex plants containing multi-integrated units within a single, flexible flowsheet.


Empowering  Refinery  Reactors Simulation

  • Reaction kinetics based on PIONA molecular structure modeling to characterize any carbon number: light end, naphtha, kerosene, diesel, gas oil, vacuum gas oil, reformate, gasoline, coker gasoline, atmospheric residue, and vacuum residue
  • The simulation is atomic balanced at any point in the flowsheet 
  • Flexible catalyst kinetic adjustments to change product yields and properties to match plant data for specific catalyst performance
  • Rigorous catalyst activity model for a variety of types of catalysts and feedstocks 
  • Optimized flowsheet performance with the Symmetry regression tools 
  • Flexible case study tools to investigate the effects of variables 
  • Providing distillation curve and product distribution of any stream in the flowsheet



Scalability is key to obtaining full value from your models, as one moves from conceptual steady state process models to detailed models with equipment design details actual plant operations.

The Symmetry environment is scalable by design so you can model across the full range of detail. Scalability is key to obtaining full value from your models, as one moves from conceptual steady state process models to detailed models with equipment design details actual plant operations.

The Symmetry environment is scalable by design so you can model across the full range of detail.

The diagram below shows a conceptual design model that evolves to a rating model with detailed equipment details to a dynamic model with the control system and pressure flow hydraulics that drive the process flows.



Get world-class simulation software for your processing applications

  • Production facilities
  • Offshore platforms
  • Gathering systems
  • Fluid properties
  • Gas hydrates
Gas Processing
  • Sweetening
  • Dehydration
  • Sulfur recovery
  • Acid gas injection
LNG Facilities
  • Cryogenic processes
  • Liquefaction
  • CO2 freezing
Oil Refining
Heavy Oil/Oil Sands Process
  • Predicting properties of heavy oil, diluents, and bitumen


Contact Us

To find out how VMG can help you solve your process challenges, email or call in the U.S. and Canada at (403) 457-4595. For all other inquiries, please fill out the form below.

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