Build139 Changes that Affect Results

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Navigation: User Guide ➔ SysCAD Version History ➔ Build 139 Release Notes ➔ Changes that Affect Results

Build 139 Release Notes (Summary)
New Models and Add-Ons Model Improvements User Interface Improvements Other Improvements Changes that Affect Results Project Upgrade & Tag Changes Discontinued Unit Models

Latest SysCAD Version: 21 September 2021 - SysCAD 9.3 Build 139.29552

Related Links: Build 139 Revision History, Upgrading Projects


Changes that Affect Results

  • Molecular Weights - The Standard Atomic Weights have been updated to latest values from IUPAC.
  • Steam IF97 equations - For steam equations, user now only has one simple choice – namely “IF97”. This uses the correct steam Enthalpy and Density equations for region5 (ie the IF97_2 equation in Build138 and earlier).
    • This may affect results if the project was using the old equation with steam at high temperatures. You can avoid this, by first ensuring you use "IF97_2" for Steam Density and Cp(Enthalpy) in Build 138 then solve and save; then on project upgrade there will be no effect on results.
    • Cfg files are upgraded in Build139, the files are not backward compatible, so if they are re-used in earlier build there will be load errors/warnings.
  • Bug fix for H2SO4(aq) if attempting to use user-defined Cp equation data (in the SysCAD.93.db3). It was always ignored, and hardwired data "KWA()" was always used. This has been fixed, user can now override the H2SO4(aq) Cp data with user-defined data.
    • This may result in change of heat flow if user-defined equation is used.
  • Precipitator3 changes:
    • GrowthAsDeposition option removed. All growth rate functions now give GrowthRateR (radial/crystal growth) as a result, with GrowthRateD (diametric/particle growth) shown independently. If a mismatch between GrowthMethod and GrowthAsDeposition is detected when upgrading to 139, a warning is shown and the option UseCorrectedGrowth should be selected. This may require retuning of growth rate and/or agglomeration rate parameters.
      PPT3 GrwChange.png
    • Evap.AllowDiscard option removed. Vapours from evaporation can no longer be discarded to "nowhere". Tanks require a Vent connection or vapours will be sent to Product (with a warning). An additional option ProdGasEntrainment has been added to allow entrainment of a fraction of vapours present in the feed or evolved from reactions. This excludes evaporation water vapour as this must be removed by definition.
      PPT3 VentChange.png
    • A correction to the calculation of thermal loss due to evaporation may cause slightly different results in tanks with an Evaporation method selected.
    • Simplification of Free-in-Space and Restricted-in-Space collision options. Agglom.UseCorrectedCollision option will show for precip tanks upgraded from earlier builds, to maintain old results. Recommend this option be selected and agglomeration parameters retuned. New tanks will include this correction automatically.
  • General Separator - Bug fixes for General Separator when using Density separation method:
    • Fixed calculations for Underflow Concentration and UF density methods, previously not returning the correct concentrations.
    • Fixed calculations when "BypassSeparCalcs" is enabled, underflow concentration and UF density methods were not returning correct concentrations.
  • Flash Tank 2 - Bug Fix for FlashTank2 in FlashTrain mode not clearing some results when model is turned Off. This may affect reported values from the FlashTank2 unit when offline.
  • Shell and Tube Heat Exchanger 2 - Bug Fix for Shell and Tube 2 model with reaction sub-model in use, the LMTD calculations has been corrected to include heat of reaction. This fix may change theoretic area and theoretical duty calculation displays, no changes to the actual duty.
  • Evaporative Dryer - if the new option UseOriginalMethod (used for backward compatibility) is unticked, different (but more accurate) solutions can be obtained in some situations. For instance, when liquids other than H2O are present in the final cake, often the target moisture content was not obtained. The new Moisture Method allows the user to specify either desired water or liquid fraction in the final cake and this will now be achieved if possible.
  • Free Energy Minimisation (FEM) - The core algorithms are completely rewritten for efficiency and stability. Substantial speed gains arise from using the previous solution as a starting point - the option UseConvergedSoln is enabled by default.
    • Results may differ in the sixth decimal place, (effectively the tolerance of the solver) and this may also affect quantities of trace species in particular. You can disable this option and rerun the model if the results are significantly different (but also check error messages - in the new build SysCAD will complain if certain thermophysical data is missing)
    • For the FixedHeat option (solving for temperature), the new algorithm will always converge - if a FixedHeat model was not converged in 138 (generally a MaxFixedHeatIterations warning, or energy imbalance), then results in 139 are likely to be significantly different.
    • The change in Molecular Weights (above) may also affect quantities of Selenium, Germanium and Cadmium in the solution since the molar flows are now different: these changes will be of the order of 0.01%.