SLB Symmetry 2025.2

Nomenclature

+ addition
o changes
x bug fix
(x.y.z) update version/build in which a feature was first available (Major.Minor.Build)
this format is used for features that were released in between major releases

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Thermodynamics
+ Added a new setting for the Thermodynamic Model: "Apply Correction to CO2 Thermal Properties". This setting applies a correction based on the Span-Wagner method to the calculated CO2 thermal properties when using the APR NG 2.0 Thermal method in the APR for Natural Gas 2 Thermodynamic Model.
+ Added an internal flag to label the Ideal Gas Enthalpy basis from the Amines 2 Thermodynamic Model as being calculated with the reference of the ideal gas heat of formation at 25 C. This allows setting the Enthalpy offset used for reactive energy balances to zero in this model.
o Improved fugacity coefficient calculations for mixed amines systems when using the Amines 2 Thermodynamic model. The improved calculations allow for a better and faster convergence of flash computations.
o Vapor phase enthalpy calculations in the Amines 2 thermodynamic model are based on the Advanced Peng-Robinson thermodynamic model.
x Fixed calculation of fugacity coefficients in SRK based property packages when the alpha function is evaluated at high temperature.
x Fixed fugacity coefficient calculations in the Amines 2 thermodynamic model when ions not participating in reactions are added to the component list.
x Fixed Status message when modifying equilibrium constant parameters for a reaction in the Reaction window from the Amines 2 property package.
x Fixed the use of "," for decimal points based on locale settings when defining chemical reactions in the Amines 2 thermodynamic model.
x Fixed vapor phase thermal conductivity calculation for the VMG(Yaws) model when Water is part of the component list but it has zero amount in the fluid. Previous calculation was considering a water pressure correction when water was in the component list but in zero amount.
x Improved phase identification for single phase fluids in REFPROP-based property packages.
x Improved the convergence of 2-phase flashes where the vapor fraction remains steady after several iterations once the residual error has been bracketed. These type of flashes could be found in water wash sections of absorption towers where a small amount of amines is present in the corresponding trays.
x Improved viscosity parameters for PGMEA (Propylene glycolmonomethyl ether acetate).
x Updated Ideal Gas Heat Capacity parameters for ALUMINUM OXIDE in the Symmetry database, new values are available in the 2025.2 Database Version and are estimated from the method used for gasification compounds.

Flaresim
x Fixed error when switching between shield types in Flaresim.

Pipe Workspace
x Fixed an issue in the Pipe Workspace where integrated Pipe-Process cases were not solving in downstream of valve as a source.

Network Solver
x Fixed an issue in the Pipe Workspace where switching the producing wells to high pressure resulted in solver error.

Dynamics
o Improved convergence of dynamics flash when there are trace amounts of hydrocarbons in water.
x Fix to prevent a crash in certain cases when being imported from a json file. The issues were present in the background dynamics objects creation.
x Fixed a bug in fluid synchronization that resulted in incorrect sizing of Dynamics Tower Section when initialized from Steady-State.
x Fixed an issue where initializing a depressuring system would fail to set a variable if a unit operation had the same name as the variable.
x Fixed issue preventing Multi-Sided Heat Exchangers from being configured properly in the dynamics engine.
x Fixed spurious increase in holdup mass when Iterate Between PFS and Comp is turned on.
x Fixed the status of the "Is Choked" checkbox in Valves that indicated choked flow even when "Choke Calculation" was set to "No Choke".
x Fixed wall temperature not updating in dynamic multi-sided exchanger causing energy balance discrepancies.

Extensions and Links
+ OLGA Link - Added variables to OLGA Link to track the status of the OLGA Server.
+ OLGA Link - Added warning message for mismatched property packages between OLGA link and connected streams.
+ OLGA Link - Added warning message when the expected and actual number of OLGA components does not match.
o OLGA Link - Updated the default maximum number of cores to use in Olga when running the OLGA link to 16. Added the option for configuring this setting in the OLGA Link's Configuration tab.
x OLGA Link - Disable Add and Delete connections buttons for upstream, downstream and signal connections when the OLGA Link unit operation is connected to the server or when the integrator is running.
x OLGA Link - Fixed a rare hang when using the Symmetry-OLGA link due to sequencing of variable connections and OLGA time-stepping.
x OLGA Link - Fixed Integrator Time synchronization issue between the internal OLGA Link time and the Symmetry flowsheet time when connecting to the OLGA server.
x OLGA Link - Fixed OLGA link composition mapping when a mix of hydrocarbons, water, and hydrate inhibitors are present in the component list, both when using Multiflash and SFE in OLGA.
x OLGA Link - Fixed the Symmetry and OLGA snapshot directory paths to handle %USERPROFILE% environment variable.

Productivity Tools
+ Optimizer - Added messages in the status bar to display the optimizer progress.
o Optimizer - Added messaging to the status bar of LEX optimizer to indicate if any manipulated variables are out of bounds. Additionally, the LEX optimizer is prevented from running if any of the manipulated variables are out of bounds.
o Optimizer - Changed the Specification Status for optimizers variables to prioritize "Out of Bounds" to "Missing Bound(s)" when the two happen simultaneously.
o Optimizer - Enhanced the status tab to display the progress of auto-perturbation as percentage.
o Optimizer - The optimization summary in the Status tab is changed for Interior Point to show the percentage improvement in the objective function, and whether or not the initial solution is feasible in which case the improvement is not reported.
x Optimizer - Fixed issues where LEX, ALM, MINLP, and MIGA optimizers were showing 'Done Solving' as a status without reaching a feasible solution. The messaging has been updated to 'No Feasible Solution Found'.
x Optimizer - Fixed optimizer plot to refresh as the optimization progresses.
x Optimizer - Fixed the discrepancy between optimizer plot data and the Results data when Maximum History points is reached.
x Optimizer - Fixed the optimizer plot options to only show active optimizer variables.
x Optimizer - Fixed the Specification Status for optimizer variables to consider the optimizer tolerances when checking for bounds.
x Optimizer - Fixed unresponsiveness when clicking the Stop button in the Optimizer when the Auto-perturbation option is enabled.

Unit Operations
+ Amine Detail - A new frame is available in the Ion Contents tab from the Amine Detail unit operation, displaying information about the reactions involved in the solution of the equilibrium reactive system. The frame is only available for the Amines 2 thermodynamic model and requires an additional license.
+ Membrane - Added new 'Side T Equal' Calc Temperature Mode to the membrane unit operation, which allows the feed side to be specified at a constant temperature and the permeate side to be specified at a separate constant temperature.
o Direct Column - The Linear Programming Split method is no longer available.
o Heat Exchanger - Changed the status message of heat exchanger's rating to be more specific when the solver failure is due to failure in flash calculations.
o Rate-Based Towers - Improved convergence by improving inner loop models and outer loop updating strategies.
o Reduced Order Model - ROM trained units copied and pasted will remain in ROM mode
x Amines and Physical Solvents are set as non-reactive in the Burner unit operation when their fuel mole flows are zero and using the Amines 2 thermodynamic model.
x Ejector - Fixed Ejector unit operation to check for supersonic conditions in its streams and show a proper warning message indicating the unreliability of calculations in this regime.
x Electrolyzer - Fixed energy balance of electrolyzer unit operations to include latent heat under two-phase operating conditions.
x Fixed issue where Cut Names were missing after copying and pasting a Distillation Curve unit operation.
x Heat Exchanger - Fixed the status message of heat exchanger to be synched with the status of its rating.
x Membrane - Fixed calculation of stage cut profiles for counter current solve method in the membrane unit operation so that stage cut profile definitions are consistent across all membrane flow patterns and configurations.
x Membrane - Fixed issue in one of the internal CounterCurrent Membrane solve methods that was excluding the sweep from driving force calculations.

User Interface
+ Flip Horizontal and Flip Vertical options added on right click of unit operations.
o Composition window will no longer accept non-numeric entries and will show an "Invalid Data Entry" message.
o Improved the reaction to open the composition window when editing mole composition in Material Streams and Cooler unit operation windows. Users should no longer lose data when typing fast.
o Material Balance Table - Selecting streams for material balance table now uses the searchable and generally more modern selection control seen elsewhere in such as Summary Sets and the material balance table Variables selection.
x Fix Reoptimize PFD silently failing when reoptimizing cases with energy connectors, and corrupting the PFD.
x Fixed PFD Messages incorrectly showing for hidden background pages.
x Fixed Symmetry partially corrupting cases when renaming sub-flowsheets.
x Fixed the report generation for Claus unit operations for both PDF and Excel report outputs.
x Material Balance Table - Items in the Selected Items list of a selection control can now be selected by clicking anywhere on the row.
x Material Balance Table - Moving groups of objects in the selection control will now move the entire group rather than just the first or last item in the group.

Built-In PFD
+ Built-In PFD - 2D shapes for all unit operations and tools are available.
+ Built-In PFD - Ability to bring shapes to front or send them back using right-click menu or shortcut keys.
+ Built-In PFD - Material Balance Tables are available. User can create new Material Balance Tables and configure existing ones.
+ Built-In PFD - Option to print PFD is available as right click option for current flowsheet or current view.
+ Built-In PFD - Text boxes are available. Text boxes support advanced configuration options.
o Built-In PFD - Zoom controls are no longer displayed on the bottom status bar when using Built-In PFD or no PFD.
x Built-In PFD - Fixed cleaning up message when cutting or deleting a special property unit operation while using Built-In PFD with datasheets.
x Built-In PFD - Fixed issue causing Symmetry to display an "Error in Accessing Required Folders" message on computers with Non-English language.
x Built-In PFD - Fixed membrane port logic to allow Sweep and Permeate ports to now have dynamic position based on the Flow Pattern variable value.
x Built-In PFD - Fixed Permissions Warning showing up on machines even with the proper permissions.
x Built-In PFD - Fixed separator port (separator 3ph vertical & horizontal) logic to allow Liq1 port to now have dynamic position based on the existence of Solid0 port for OLI link.
x Built-In PFD - Fixed SymmetryUIBackgroundService.bat not registering the Built-in PFD properly in languages that are not English.
x Built-In PFD - Unregistered extension unit ops will now appear as a default white box on the Built-In PFD.

Documentation
+ Added documentation for the Currency tab of the Economics module in the Symmetry user manual.

Miscellaneous
x Fixed an issue where hypo creation failed when running a tst file due to multiple matching units (e.g., kPa and kPa(g)).
x Fixed the interpretation of previously unhandled formats of OLI hypothetical component formulas when importing OLI dbs file.
x HYSYS XML import - Fixed issues preventing proper connections between a spreadsheet (process calculator) cell with a formula to another spreadsheet or to an adjust (controller).