Architecture and new interfaces of DWSIM
open-source process simulator.

Should I use DWSIM or DWSIM Pro?

Both versions address different needs. The following table explains the differences.

Terms and Conditions (Commercial)




How you can use the software as an end-user.

GPL (v3)

Named user license

Program version

Which versions you can use as an end-user.

Latest version published on Sourceforge

All older versions available

Built regularly, but not following every version


How much you pay for the usage.


Different paid plans available


How you get help with your simulation task or using DWSIM.

Forum support (public)

Personal (private) support

Forum support (public)

Access (Technical)



Installation and updates

Where the software is installed and who installs updates

You install and update on your own machine

We install on our servers


How you start and use the program

Start the DWSIM program on your operating system (Windows, Linux, MacOS)

Open the DWSIM Pro app in a browser and log in with your personal credentials

Physical Properties



Coming soon

Connect with OLI Engine

Combine the rigor of OLI’s¹ electrolyte approach with DWSIM Pro and accurately account for the electrolytes in your system. This technology uses the same OLI Engine that is used in OLI standalone products.

Separate OLI license required

Connect with REFPROP

REFPROP is an acronym for REFerence fluid PROPerties. This program, developed by the National Institute of Standards and Technology¹ (NIST), calculates the thermodynamic and transport properties of industrially important fluids and their mixtures.

REFPROPTM is based on the most accurate pure fluid and mixture models currently available. See the REFPROPTM website for a detailed list of data and features of REFPROPTM.

Separate REFPROP license required

CoolProp Property Package

Calculate phase properties based on simple mole averages of pure fluids with CoolProp libraries. Phase equilibria are calculated considering the mixture as ideal.

Extended CoolProp Property Package

Adds rigorous calculations for mixtures using high-accuracy Helmholtz mixing rules and equilibrium calculations using CoolProp’s own flash algorithms.

Unit Operations



Pipe Network

Modelling and simulation of pipe networks connected through nodes with multiple sources and sinks. Rigorous compositional fluid property calculations are done by DWSIM Property Packages.

  • Supports Pipe Segments with Rigorous Heat Transfer calculations, Valves, Pumps, Compressors and Gas-Liquid Separators;
  • Rigorous fluid properties and phase distribution calculated with DWSIM Property Packages
  • Fully-featured Graphical Network Designer
  • Supports Pressure and Mass/Molar/Volumetric Flow specification on endpoints (Sources and Sinks)

Up to 20 network objects

Unlimited number of network objects

Air Cooler

Modeling of Air Coolers with three calculation modes: Specify Outlet Temperature, Specify Tube Geometry and Specify Overall UA.

Falling Film Evaporator

Modeling of Falling Film Evaporators with three calculation modes: Outlet Temperature, Outlet Vapor Mole Fraction and Energy Stream. You can also set the number of equilibrium calculations (steps) inside the evaporator.

Advanced energy and material stream handling

Splits an energy stream into two or three other streams.

Mixes up to six energy streams into a single one.

Allows the user to define an expression which, when evaluated as True, will redirect the inlet stream to the first outlet stream, and to the second outlet stream if the expression is evaluated as False.


PPBDesigner simulates the most industrially important liquid-liquid extraction columns such as agitated and non-agitated columns. The column module can be integrated with other flowsheet modules for a complete chemical process flow diagram simulation.

Separate PPBDesigner license required

External Equation Solvers



Python SciPy

Pre-installed interfaces for Python’s SciPy  global minimization methods like Dual-Annealing, Basin-Hopping and Differential Evolution.

Extreme Optimization

Pre-installed interfaces for Extreme Optimization‘s Non-Linear System, Non-Linear Optimization and Ordinary Differential Equation (ODE) solvers for increased robustness and up to 3x faster solving times.




Excel Reporting

Excel Reporting is an extension to generate reports for all objects on the flowsheet. You can customize the objects and properties to show, and select a custom display order. The generated report can be saved to a XLSX worksheet file. It does not require Microsoft Excel to be installed in order to generate the reports.

Capital Cost Estimator

Capital Cost Estimator is an extension that allows the estimation of Capital and Operating Costs for a Chemical Processing Plant based on data from the currently active flowsheet. 


  • CAPEX/ OPEX Capital Cost Estimation
  • Yearly Operating Cost Estimation
  • Saving/Loading of Cost Reports
  • Compare multiple Cost Reports
  • Export results to DOC/ODT/XLS/ODS/PDF files
  • Automatic mapping for selected equipments, product/raw streams and utilities
  • Price correction based on CEPCI and IPC Cost Indexes
  • Currency conversion
  • User-defined Equipments, Materials and Utilities

Simulate 365 Applications




The simulation filemanagement system.

Design of Experiments (DoE)

Run a series of simulations.

Separate DoE license required

Take-Home Exercise / Exam (THEE)

Generate any number of flowsheet simulations for classroom exercises or as individualized exams.

Separate THEE license required

Multivariate Sensitivity Study (MSS)

Calculate the multidimensional solution space (hypercube) of a flowsheet simulation.

Separate MSS license required

Machine Learning (ML)

Create and replace rigorous first principle models of unit operations or flowsheets by Artificial Neural Networks trained by DWSIM data.

Run Surrogate Models from several sources, e.g., process control systems (PCS; plant data) or process simulators (rigorous first-principle modelssimulation data) in DWSIM.

Extend DWSIM ("Hooks")




Create and run Python scripts in DWSIM.

Python (Protected)

Create and run proprietary², licensed Python scripts in DWSIM.

Dynamic Link Libraries (DLL)

Create and run custom² DLL files in DWSIM.

Custom Menus

Create your own menus² in DWSIM or extend existing DWSIM menus with your own items.

External SciPy and Extreme Optimization solvers

Implementations of interfaces for Python’s SciPy methods and for Extreme Optimization‘s solvers. See the section above for details.

MATLAB Applications

Use DWSIM with applications based on MALTLAB(R) 

A unit operation implemented in MATLAB can use DWSIM as a graphical user interface (GUI). See PPBDesigner under the above section Unit Operations.

Partner Applications

Use DWSIM with applications from selected market-leading software vendors¹.

Or extend DWSIM with functionality¹ that is run on initialization of the flowsheet or extension.

¹Contact us at, if you are a software vendor with an application that could nicely integrate with DWSIM.

²Contact us at, if you want to extend DWSIM using one of the hooks.