The OLI Databank

OLI Systems, Inc. - founded in 1971 by Dr. Marshall Rafal - has developed commercial computer software and databases that simulate aqueous-based chemical systems and employ a predictive thermodynamic framework for calculating the physical and chemical properties of multi-phase, aqueous-based systems.

OLI provides a family of software simulation tools (for example StreamAnalyzer, CorrosionAnalyzer, WaterAnalyzer) that address a wide range of applications - from rates of corrosion, oil and gas well plugging, and wastewater treatment, to chemical processing plant operation and optimization, reactive separations, and environmental simulations.

The core data are stored in the OLI Databank (Public.ddb) that contains thermodynamic, transport, and physical properties for 79 inorganic elements (including actinides, heavy and precious metals) and their associated aqueous species. The databank also includes over 3000 organics (including electrolytes, chelates and organo-metallic species) applicable in the following ranges: temperature, -50 to 300 °C; pressure, 0 to 1500 bar; ionic strength, 0 to 30 molal. It also contains data for the non-ideal gas phase and for many pure solid precipitates. Thus many common mixtures of chemicals in water can be modeled.

FactSage Aqueous Databases

FactSage offers the following aqueous databases:

• very dilute solutions - Henrian activity coefficients at 25 °C for about 300 aqueous species stored in the FACT compound database. These data can be accessed through the View Data, Reaction, EpH and Equilib modules.
• non-dilute solutions - Pitzer parameters at 25 °C for about 100 species stored in the FACT solution database. These data are accessed through the Equilib module.
• dilute high temperature solutions - Helgeson database (including Debye-Huckel and Davies dilute solution activity models integrated into the HKF equation of state) on over 1300 aqueous species. These data are stored in the FThelg database (released in November 2004 with FactSage 5.3.1) and are accessed through the Equilib module.

None of the FACT aqueous databases offer the species selection, temperature and pressure ranges that are available in the OLI Databank. Hence it was decided to develop a link between the FactSage and OLI software that would enable a FactSage user to import OLI aqueous data (possibly together with FACT, SGTE and other data) and employ them in Equilib calculations.

OLI StreamAnalyzer and FactSage Equilib

The OLI StreamAnalyzer (the software supplied by OLI) performs calculations similar to the FactSage Equilib module. For example with the StreamAnalyzer you can run

SinglePoint Calculations - i.e. Equilib equilibrium calculations:
• isothermal - same as in Equilib
• adiabatic - in Equilib Delta H or H(product) can be constrained
• bubble point - Equilib gas formation target
• dew points - Equilib aqueous formation target phase
• set (i.e. target) pH - not yet in Equilib, but you can set other activities and potentials
• precipitation point - Equilib precipitate target phase
• composition targets - not yet in Equilib, but you can specify the amount of a target phase
• transport properties - not yet in Equilib
• etc.

  Survey Calculations - similar to tabular and graphical displays in Equilib and Results:

• temperature, pressure, composition and pH surveys on any stream
• both a primary (one variable adjustment) and a covariant (two variable adjustments) are supported.
• graphical reporting of the results
• etc.

Following extensive FactSage program development we are pleased to report Equilib is now able to access the OLI Databank and perform many of the OLIStreamAnalyzer SinglePoint Calculations. At 25 °C the results are nearly identical or very similar - see Comparison of OLI StreamAnalyzer and FactSage Equilib Results later on.

In addition, one can also import FACT and SGTE data (solid compounds and real solutions) into the calculations and include them as possible products, although thermodynamic consistency with the OLI data can not be guaranteed. (At the present, when FACT and SGTE data are used only full redox equilibrium calculations can be performed.)

How FactSage Users Can Access the OLI Databanks

For FactSage to access the OLI databanks both FactSage and the OLI StreamAnalyzer must be installed on the same PC, and both software packages must be fully licensed and operational (i.e. not demonstration, setup or time expired versions).

In the case of FactSage it must be the current version (or update) that has been released within the previous 12 months - if it is more than 12 months old then the FactSage - OLI Databank link will no longer work. For example, in the case of FactSage 5.3.1 which was released in November 2004, the link will be OK until the end of November 2005.

In addition you will need to install a security program supplied by us that will enable FactSage to access the OLI security key (dongle). Equilib should then be able to access the electrolyte data from the OLI Databanks and include them in the calculations. If your PC is connected to 2 dongles (one OLI dongle and one FactSage dongle) make sure the dongle for OLI is connected first (i.e. closest to the PC) - it works better that way.

Adding OLI Databanks to the FactSage List of Databases

In order to include the OLI databanks in calculations FactSage must be informed of where to find them. This is usually done by adding them to the FactSage list of databases via the View Data Module. For example, in the FactSage main menu click on View Data to open the View Data module and then click on the ‘Add ...’ button.

(Alternatively in the [Reactants Window] of Equilib click on ‘Data Search > Databases > File > Add ...’).

This opens the [Compound (or Solution) – list of databases Window] – for OLI Databanks compound and solution data are stored in the same file, so you can specify either Compound or Solution and it makes no difference since it is the same databank.

Click on ‘Browse’ to open the [Open Window]. At the bottom click on the ‘Files of type’ drop down menu and make sure ‘OLI Systems database (*.ddb)’ is selected.

Now locate the folder where the OLI databanks are stored (for example 'c:\Program Files\Oli\Databanks\'). Select ‘Public.ddb’ and click on ‘Open’ – this returns you to the [Compound – list of databases Window]. Now click on ‘OK’ to add this ‘OLIP’ databank to the list of databases. Since OLIP (i.e.Public.ddb) is the core of the OLI databanks it must be added first.

You can also add other OLI databanks such as:

• OLIC (Corrosion.ddb) the Corrosion Databank for the CorrosionAnalyzer.
• OLIG (Geochem.ddb) the Geo Chem Databank for minerals.
• OLIL (LowTemp.ddb) the Low Temp Databank for minerals at less than 0 °C.

Including/Excluding OLI Databanks in Calculations

(You can ignore this section if you are going to run the Sample Calculations using OLI Databanks - see next section.)

In order to include or exclude the OLI databanks in your Equilib calculations, click on the ‘Data Search > Databases > ... ’ menu bar at the top of the [Reactants Window].

This opens the [Databases Window] that that lists all databases. Click on the "+" column of OLIP in order to include the database in the data search. Repeat for OLIC, OLIG, OLIL etc. as required.

Sample Calculations using OLI Databanks

For these examples to work both FactSage and the OLI StreamAnalyzer must be installed on the PC, and the OLIP (Public.ddb) databank must be in the list of databases (to see how this is done refer to an earlier section on Adding OLI Databanks to the FactSage List of Databases). However it is not necessary to Include OLI Databanks in Calculations as discussed in the previous section since the sample files automatically do this for you.

In the [Equilib Reactants Window] click on ‘File > Directories > OLI Systems Examples’ for sample calculations. These examples introduce the OLI Systems Databanks and show how to use Equilib to perform a variety of calculations (ex: NaCl solubility in water; water and benzene equilibrium; combined FACT and OLI database calculations, SGTE alloys in water).  

• NaCl(s) solubility in water at 25 °C - an introduction to Equilib and the OLI Databank.
• Water and benzene equilibrium at 25 °C - an example the Oli option ‘2nd liquid’.
• Water and benzene and excess NaCl(s) at equilibrium at 25 °C.
• Water and benzene and excess NaCl(s) at equilibrium at 25 °C - example the OLI option ‘Include Redox’.
• Effect of NaOH addition on the pH of an acetic acid/sodium acetate buffer.
• pH of a weak acid/congugate base buffer - effect of NaOH on lactic acid/sodium lactate.
• Water - methanol - MgSO4 transitions at 25 °C. Alpha composition variable; phase transitions; dormant species.
• Ammonia in water - example of adiabatic decompression from 200 °C and 10 atm.
• Ammonium acetate in water - example of phase transitions (dew point and bubble point).
• Ammonium chloride in water - example of phase transitions and gas-solid phase equilibrium.

Additional sample calculations are available - these include:

'H2O + 10 molal NH4Cl - phase transitions', 'Arsenic V acid with sodium hydroxide - an example of an aqueous poly-basic titration', 'Copper dissolution in aqueous ammonia - an example of partial redox', 'CuO + NH3 with (NH4)2SO4 - no redox', 'NiO + NH3 with (NH4)2SO4 in air - partial redox', 'PbCl2 in aqueous NaCl - an example of enhanced solubility by complex formation' 'Ni-Fe leaching in aqueous ammonia - a metallurgical example of partial redox with H2 formation suppressed', 'Aluminium hydroxide solution in pressurised aqueous NaOH - an example of the principles of the Bayer Process', 'Cyanidation of Au-Ag as an ideal solution alloy', 'AgCl + Pb in aqueous NaCl - example of cementation with partial redox and H2 formation suppressed', 'CdSO4 + Zn in aqueous solution - example of cementation with partial redox and H2 formation suppressed', 'Reduction of NiSO4 from aqueous NH3 solution by H2 - a metallurgical example with partial redox', 'Titration of iron II with dichromate - example of a redox titration with O2 formation suppressed', 'Activity of FACT Fe(s) vs OLI Fe(s) - effect of OLI's polynomial fit of Helgeson's solute model', 'Evaporation of sea water under air at 25 °C - example of sequential precipitation', etc.

Most of the OLI sample calculations have been prepared by Dr. Michael (Mike) W. Wadsley, Austherm Pty Ltd as part of the FACT Industrial Consortium Project. For more information Mike may be contacted by email at Wadsley@austherm.com.au.

Comparison of OLI StreamAnalyzer and FactSage Equilib Results

If you examine the above examples you will note that the StreamAnalyzer results are never identical to the Equilib results for the same calculation, even when accesssing the same database(s).

• OLI Public database only
  When the StreamAnalyzer and Equilib programs access the OLI Public database (Public.ddb), although the database is the same the algorithms for calculating the thermochemical equilibria are totally different and the properties accessed in these calculations are also different. Also slightly different values are adopted for physical constants such as the gas constant.

  Generally, the StreamAnalyzer applies a Newton-Raphson iteration technique on the equilibrium constants (K-fit polynomials). The calculation is efficient but only applicable to aqueous-based systems up to 300 °C. On the other hand Equilib applies a general Gibbs energy minimization approach to the thermodynamic data (derived in part from the K-fit polynomials) for each compound and solution phase, and the aqueous phase is treated just like all the other phases. The calculation is much slower, but it is more general and not limited to aqueous-based systems.

  At 25 °C the two sets of results should be in good agreement. However as temperatures increase the agreement may not be as satisfactory (due to an increasing inconsistency between the K-fits and the derived thermodynamic data), but nevertheless the difference between the sets of results should still be very acceptable. We believe that the calculated results between FactSage and OLI are equivalent when numerical accuracy and different values for primary constants are considered.

• Mixed OLI and FactSage databases
  You can import FACT and SGTE data (solid compounds and real solutions) into the calculations and include them as possible products. This must be done with considerable caution because the method OLI uses to calculate the thermodynamic properties of solid species differs significantly from that used by FactSage. Because the OLI codes indicating valence have not yet been assigned in the FactSage databases, the Full Redox option is currently automatically invoked when mixed databases are used. You may delete undesired species from the system in the usual manner.

  At 25 °C, data from the OLI databases should be in reasonable agreement with data on the pure solid species with the same chemical formula from FactSage databases since the original standard state data are often taken from the same source. The method OLI uses to calculate the thermodynamic properties of solids is that for low solubility solids, when the default calculation method is used, the calculated values are less accurate at temperatures below 25 °C and above 100 °C. That is, OLI solid precipitates are consistent with OLI aqueous data; FACT and SGTE solid precipitates may not be consistent with OLI aqueous data, especially at higher temperatures. It is suggested that if you are working at these conditions with low solubility FACT solids in the system, you activate the ‘Helgeson direct’ option. With this option active, calculation times will be significantly increased.

  Also, unlike FactSage solid species, in Equilib precipitates from OLI databases can not be extrapolated outside their reported temperature ranges.

OLI Options in Equilib

When the OLI Databank is included in the Equilib calculation, the [Equilib Reactants Window] automatically displays the following OLI Options :

• Include Redox
  Let us consider the dissolution of NaCl(s) into water as Na[+](aq) + Cl[-](aq). For FACT database calculations with the ‘aqueous phase’ or ‘FACT-PITZ’ (Pitzer parameters) redox reactions involving changes in oxidation states can take place. This leads to the formation of a variety of additional aqueous species such as ClO[-1](aq), Cl2(aq), ClO2[-1](aq), HClO2(aq), ClNaO3(aq), ClO3[-1](aq), etc. Although thermodynamically stable the actual formation of such species may not occur because of kinetic factors. For OLI data it is possible to control which redox reactions are permitted. If ‘Include Redox’ is NOT checked then only Na[1+] and Cl[1-] oxidation states are permitted and this leads to a much simpler equilibrium. If ‘Include Redox’ is checked then all (or some, you are presented with a selection) possible oxidation states are permitted. (Note: when other databases (FACT, SGTE) are included in the data search then ‘Include Redox’ is automatically checked and full redox calculations are always performed - that is, with mixed databases it is not possible to suppress the redox reactions.)

• 2nd Liquid
  For FactSage Databases (FACT, SGTE, etc.) compound and solution phases can be included as possible products via the [Equilib Menu Window]. However inclusion of an OLI liquid phase (other than water, benzene for example) requires a special treatment. If you wish to include as a possible product the formation of a second liquid phase then the ‘2nd Liquid’ option must be ‘checked’. This phase then becomes active in the [Menu Window]. For ‘2nd liquid’ calculations OLI requires that the gas phase be present. In the [Menu Window] if you add/remove the gas (for example click on the gas ‘+’ box) then the ‘2nd liquid’ phase is automatically included/excluded in the calculation.

• Helegeson Direct
  This option is special to the OLI Databanks and becomes important at higher temperatures. When this option is activated the calculation speed may be slower but the Helgeson infinite dilution Cp equations are used in their complete and more accurate form.

• List Inflows
  This option assists in the entry of the reactant species by proposing a list of possible inflows that match what you are typing. The list contains both the chemical formulae (case sensitive) and OLI component names (uppercase) for all species stored in the OLI Public databank. For example if you type the chemical formula 'C6' it will propose 'C60H122 HEXACONT' followed by 'C65H122 PENHEXCONT' and so on, or if you start with the OLI component name 'BENZ' it will propose 'BENZENE C6H6' followed by 'BENZIDINE C12H12N2' etc. By clicking on one of the proposed inflows the rest of the species is automatically filled for you. This feature is mainly used to save time in identifying complex organic species. Since sodium chloride is stored under the formula 'ClNa' and OLI component name 'NACL' then although entry of say 'NaCl' is permitted it would not appear in the list of proposed inflows.

• Help Button
  Click on 'Help' to display this file you are currently reading.

Restrictions on Equilib when accessing OLI Databanks

The list of restrictions will change as the FactSage-OLI interface is developed. Currently OLI Databanks can only be included in Equilib calculations. For example it is not possible to access the OLI Databanks through the View Data module.

The following is a partial list of restrictions on Equilib when OLI Databanks are included in the calculation.

• [Reactants Window]
  All reactant species (i.e. OLI Inflows) must come from the OLI Databanks. The following are deactivated: Reaction Table, Input Stream, Initial conditions.

• [Menu Window]
  The gas and aqueous phases can contain only OLI species - that is, it is not possible to include aqueous species from the FACT database. The upper temperature limit is 300 °C. Use the Equilibrium option 'Transitions' option with caution. The following are deactivated: Equilibrium Options: Predominant and Open.

• [Results Window]
  Unlike FactSage compound species, OLI species can not be extrapolated outside their reported Cp(T) ranges. Where possible such species will be automatically dropped from the Equilib calculation. If not then an offending species will be flagged since its calculated value may be so inaccurate as to be meaningless. OLI solid precipitates are consistent with OLI aqueous data; FACT solid precipitates may not be consistent with OLI aqueous data, especially at higher temperatures.