Work at SourceForge, help us to make it a better place! We have an immediate need for a Support Technician in our San Francisco or Denver office.


DWSIM - Open Source Process Simulator / News: Recent posts

DWSIM v3.0 Build 5031 released

Build 5031 was released for Windows, Linux and OS X. This is a major release with lots of new features and enhancements. DWSIM is an open-source chemical process simulator with advanced thermodynamic models and CAPE-OPEN support.

Posted by Daniel Medeiros 2013-10-11

DWSIM v2.1 Build 4534 released

Build 4534 was released for Windows (.NET), Linux and Mac (Mono). This is a bugfix release. DWSIM is an open-source chemical process simulator with advanced thermodynamic models and CAPE-OPEN support.

Posted by Daniel Medeiros 2012-05-31

DWSIM v2.1 Build 4503 released

Build 4503 was released for Windows, Linux and Mac. This build adds new flash algorithms and a new property package. A portable version for Windows is now available. DWSIM is an open-source chemical process simulator with advanced thermodynamic models and CAPE-OPEN support.

Posted by Daniel Medeiros 2012-05-01

DWSIM v2.1 Build 4466 released

Build 4466 was released for Windows (.NET), Linux and Mac (Mono). This build adds features and fixes some bugs. DWSIM is an open-source chemical process simulator with advanced thermodynamic models and CAPE-OPEN support.

Posted by Daniel Medeiros 2012-03-24

DWSIM v2.1 Build 4452 released

DWSIM v2.1 Build 4452 was released for Windows, adds a Petroleum Assay Manager and PFD Zoom All/Pan features among others. DWSIM is an open source chemical process simulator.

Posted by Daniel Medeiros 2012-03-10

DWSIM v2.1 Build 4438 released

DWSIM v2.1 Build 4438 was released (Win/Linux/OSX). This build fixes some bugs and enhances the Adjust Logical Operation. DWSIM is an open source chemical process simulator.

Posted by Daniel Medeiros 2012-02-25

DWSIM v2.1 Build 4416 released

DWSIM v2.1 Build 4416 is out. DWSIM is an open source chemical process simulator.

New features: PRSV2-VL Property Package, includes ChemSep 6.90 installer w/ 400+ compound database

Posted by Daniel Medeiros 2012-02-04

DWSIM 2.1 Beta released

DWSIM v2.1 Build 4410 Beta is out. DWSIM is an open source chemical process simulator.

New features: Data Regression utility and PRSV2 Property Package

Posted by Daniel Medeiros 2012-01-30

DWSIM 1.8 Build 4089 (Mono Edition) released

Build 4089 for Mono is now available for download. The Mono Edition is a slightly less featured version of DWSIM, but allows DWSIM to run on Linux and Mac systems.

  • Changes:
  • [FIX] Spreadsheet Tool re-enabled for Mono Edition
  • [FIX] IO Flash 'Fast Mode' re-enabled for Mono Edition
  • [FIX] General Exception Handler re-enabled for Mono Edition
  • [FIX] Fixed unhandled exceptions when using petroleum characterizaton and hypo generation tools
  • [FIX] Property Package configuration window is now working correctly
Posted by Daniel Medeiros 2011-03-13

DWSIM 1.8 Build 4080 (.NET) / 4081 (Mono) released

Build 4080 for .NET and 4081 for Mono are now available for download.

The Mono Edition of DWSIM is a slightly less featured version of DWSIM, but that's for a good reason: you can now run DWSIM on Linux machines using Mono.

Both builds (.NET and Mono) come with a couple of new features: scripting support for pre- and post- Unit Op calculations and a model for Shell and Tube Heat Exchanger rating. I also noticed some problems with the IO Flash algorithm and added a checkbox to disable "Fast Mode" for it. It just enables the calculation of a damping factor on each iteration to improve convergence robustness.

Posted by Daniel Medeiros 2011-03-06

DWSIM 1.7 Build 3875 released

This release includes a German translation by Rainer Göllnitz.

Posted by Daniel Medeiros 2010-08-11

DWSIM 1.7 Build 3868 released

This release includes the interface for external plugin development (specific documentation to come later) and updates to rigorous column solvers (IO and SC). Changelog:

  • [NEW] Interface definition for external plugins
  • [FIX] Updated Rigorous Column solvers (Inside-Out and Simultaneous Correction)
  • [FIX] Updated Critical Point calculation
Posted by Daniel Medeiros 2010-08-06

DWSIM 1.7 Build 3850 released

Minor fixes and the new Lee-Kesler-Plöcker Property Package. Changelog:

  • [NEW] Lee-Kesler-Plöcker Property Package
  • [FIX] Fixed K-value calculation call in the Sum Rates method for solving Absorption Columns
  • [FIX] Fixed IO Flash calculation in single phase region
  • [FIX] Fixed Critical Point calculation with PR and SRK Equations of State
  • [FIX] Fixed portions of GUI language that were not being set on the first run
Posted by Daniel Medeiros 2010-07-17

DWSIM 1.7 Build 3840 released

Build 3840 introduces the Gibbs Reactor and comes with important changes in the thermodynamics framework. Changelog:

  • [NEW] Gibbs Reactor model (vapor phase only) with two solving methods: reaction extents and direct minimization
  • [NEW] New global settings for Property Packages: Flash Algorithm and Calculate Bubble/Dew points
  • [NEW] New approach for equilibrium calculation: Inside-Out by Boston and Britt
  • [NEW] Added an option to adjust Rackett Parameters and Acentric Factors to match SG and NBP in Petroleum Characterization Utilities
  • [NEW] New Quick Settings toolbar: Unit system and number formatting
  • [NEW] New menu gives quick access to DWSIM Tools
  • [NEW] Added the option to select stream component amounts as properties to show on PFD tables
  • [CHG] Completely rewritten Equilibrium Reactor model
  • [CHG] Updated ChemSep database loading code to support ChemSep 6.62
  • [FIX] Fixed an exception when working with pump curves to calculate pump power
  • [FIX] Fixed a bug in temperature calculation with the Steam Tables Property Package... read more
Posted by Daniel Medeiros 2010-07-09

DWSIM 1.6 Build 3676 released

Build 3676 fixes a lot of bugs and adds important features to DWSIM. What's new:

  • Napthali-Sandholm Simultaneous Correction (SC) method for rigorous column solving
  • New Flowsheet color scheme, improved connector drawing algorithm, faster object drawing
  • Expression support for the Sensitivity Analysis Utility
  • Support for performance & system curves in the Adiabatic Pump

Updated documentation, samples and source code in VB.NET are also available for download in the "Files" section.

Posted by Daniel Medeiros 2010-02-05

DWSIM 1.6 Beta Build 3605 Released

DWSIM 1.6 Beta is now available for download. Here is the list of changes since build 3399:

  • [NEW] Added Spanish GUI translation (many thanks to Abad Lira and Gustavo León!)

  • [NEW] Added a Multivariate, Constrained Optimization utility

  • [NEW] Added a Sensitivity Analysis utility supporting up to 2 independent variables

  • [NEW] Added "command-line run mode" (read the documentation for more details)... read more

Posted by Daniel Medeiros 2009-11-15

Blog updated

DWSIM's Blog was updated with a quick preview of the new features which will be available in the next build. Visit for more details.

Posted by Daniel Medeiros 2009-08-31

DWSIM 1.5 beta build 3399 released

This one was fast. I just found an error in the calculation of the ideal gas enthalpy/entropy for ChemSep/CheResources components that affects all unit ops' heat balances, so it just couldn't wait. Other fixes were included as usual.

I also created a new simulation file reproducing the PS Azeotropic Distillation (Methanol/Acetone) case built by Harry Koojiman for the COCO simulator.

Go to the download page ( to get the files.

Posted by Daniel Medeiros 2009-04-22

DWSIM 1.5 beta build 3398 released

This updated v1.5 build fixes some bugs reported by users and others found during testing sessions. New features include:

  • Component volumetric flow /fraction information in Material Streams;

  • The possibility to choose how the liquid density should be calculated with EOS-specific Property Packages - use the EOS itself or the Rackett equation. This decision directly affects the calculation of partial volumes (used for the calculation of the volumetric fractions/flows).

Posted by Daniel Medeiros 2009-04-21

DWSIM 1.5 beta build 3377 released

DWSIM Build 3377 was released yesterday and adds important features to the Calculator, like 'abort calculation' and 'recalculate flowsheet'. Some bugs were also fixed, as usual.

Because of the changes needed to implement the new features, the interface became even more responsible during calculation. Check it out!

Posted by Daniel Medeiros 2009-04-02

DWSIM 1.5 beta build 3372 released

DWSIM v1.5 beta build 3372 is available for download. This is just a maintenance release with some bug fixes and optimizations. Most important corrections are in the calculation of viscosity and surface tension of liquid mixtures. Also, the components that are missing some important data (like acentric factor and critical compressibility) in the CheResources database are now marked in red for your convenience.... read more

Posted by Daniel Medeiros 2009-03-26

DWSIM 1.5 Beta released

DWSIM 1.5 Beta is now available for download. Here is the list of changes since version 1.4:

  • [NEW] Redesigned component database system
  • [NEW] Added two new Property Packages: NRTL/Peng-Robinson and UNIQUAC/Peng-Robinson
  • [NEW] Added support for loading ChemSep(TM) databases
  • [NEW] Added a tool to characterize petroleum fractions from ASTM/TBP distillation curves
  • [NEW] Added a tool to insert user-defined components
  • [NEW] Added the ability to use multiple property packages in a single simulation
  • [NEW] Dockable help window with localized tips
  • [NEW] New Unit Operations: Distillation Column, Absorption Column, Refluxed Absorber and Reboiled Absorber
  • [NEW] Rigorous Column solving methods: Bubble-Point, Sum-Rates and Inside-Out
  • [NEW] New utility for calculation of Petroleum Cold Flow Properties
  • [CHG] Surface Tension is now correctly listed as a liquid phase property
  • [CHG] Redesigned splash and welcome screens
  • [BUG] Fixed high-pressure vapor viscosity calculation
  • [BUG] Fixed liquid viscosity calculation error when supercritical components are present
  • [BUG] Fixed flash calculation vapor fraction initialization error (should avoid some impossible solutions)
  • [BUG] Fixed culture-specific error related to Property Package parameter storage
  • [BUG] Fixed calculation of vapor phase thermal conductivity
  • [BUG] Fixed a bug in internal calculation of heat capacity ratio
  • [BUG] Fixed MRU filelist... read more
Posted by Daniel Medeiros 2009-03-07

DWSIM 1.4 released

DWSIM version 1.4 is now available for download. Major changes include the addition of three new unit operations (Equilibrium Reactor, Shortcut Column and Heat Exchanger [basic]) and three utilities (PSV/Vessel sizing and Spreadsheet).

The documentation is not up-to-date (lost my Lyx installation), so it will probably be updated only in the 1.5 version release, which shouldn't take too long and will include a Rigorous Column unit operation.... read more

Posted by Daniel Medeiros 2008-11-05

Latest SVN updates & more

The latest SVN update contains important bug fixes to the True Critical Point utility. In case you haven't noticed, Prof. Cartaxo also included a basic implementation of the Heat Exchanger Unit Operation. You can also find among the Property Packages an initial implementation of Michelsen's stability algorithm, which, hopefully, will evolve to a full Multiphase Property Package for DWSIM. Stay tuned!

Posted by Daniel Medeiros 2008-09-13

DWSIM 1.3 released

DWSIM version 1.3 is now released along with documentation in English and Portuguese Brazilian languages. You can also find in the Downloads page an example simulation (Cavett's problem) in order to view some of DWSIM's main features.

This release is the first to be hosted on SourceForge and is licensed under the GPL v3 license. The source code can be compiled with Visual Basic 2005 Express Edition (a free Visual Studio VB.NET-specific version).... read more

Posted by Daniel Medeiros 2008-07-11