Alumina 3 Bayer Species Model
|Alumina 3 Bayer Species Model||Species Model Theory||General Discussion|
- 1 General Description
- 2 Required Chemical Compounds
- 3 Model Theory
- 4 Bayer Property Calculation Method
- 5 Selecting a Bayer Species Model in a Feeder
- 6 Bayer Liquor Calculator
- 7 Size Data
- 8 Data Sections
The Alumina3 Bayer species model is used to calculate the properties of fluids within an Alumina project using equations defined in the public domain.
Required Chemical Compounds
The following species are referenced by the Alumina3 set of models and are required in the species database and configuration file, except for Sodium Fluoride, which is optional. If it is present in the database, its effects will be included in the correlation calculations.
|NaF(aq)||-||Sodium Fluoride (Optional)|
|Na2C5O7(aq)||-||Organic compound representation|
|NaOH*(s)||-||Bound Soda (Optional) NOTE: This is only used when using the Precipitation3 unit operation.|
|Na2C5O7*(s)||-||Bound Organics (Optional) NOTE: This is only used when using the Precipitation3 unit operation.|
Note: Sodium Fluoride is not required but will be included in total sodium calculation if present.
Please see Species Model Theory for the equations used.
All of the properties that are not explicitly calculated by this model are calculated using the Standard Species Model.
Please see General Bayer Data for some general discussion topics.
Bayer Property Calculation Method
Some Bayer properties have different calculation methods, user may select which method to use in the project. Please note that the method selected is Global to the project.
The method and Constants selection can be selected from Plant Model - Global Tab:
Please see Global Properties Calculation Method Selection for more information.
Selecting a Bayer Species Model in a Feeder
The user must have a project that includes a Bayer species model in the configuration file as shown below.
It is then possible to select the Bayer model (either Bayer3 or a Client Specific Bayer model).
- On the Feeder access window there is a field 'SpModel.Reqd' where the user may select the model, as shown below:
|Tag / Symbol||Input / Calc||Description|
|SpModel.Reqd||Inherit||Model used follows upstream units.|
|Standard||All the variables are calculated using the Mass Weighted Mean of the species.|
|A Bayer Model||('A Bayer Model' will be the Bayer model included in the configuration file. In the view above this is 'Bayer3'). Density, Cp, Boiling Point Elevation, etc calculated using the equations defined for that particular Bayer species model.|
Bayer Liquor Calculator
When defining a Bayer Liquor stream, it is possible to have SysCAD calculate the feed composition based on user defined Bayer species concentrations and ratios.
This is done in the Feeder unit - but only in a 'True' feeder, i.e. not connected to a sink on a different flowhseet:
- First turn on the Calculator, by ticking the Calculator checkbox () located on the FeederSink Tab,
- Then go to the newly created tab called Calc, and define the required composition.
- NaF_Reqd is only visible if it is selected in the project configuration file.
- OtherLiquidMethod is only visible is there are other liquid species selected in the project configuration file in addition to the Required alumina 3 liquid species.
This is shown in the images below:
- For more information on the feed calculator variables, please see Calculator - Bayer Feed Calculator.
The calculated feed composition will be set into the DSp tab. The variables set by the calculator are indicated by the yellow background.
- If the calculator is enabled, the user may NOT manually change the feed composition on the DSp tab. All changes must be made on the Calc tab.
- The calculator will calculate the required concentration based on the required alumina 3 liquid species, if other liquid species are present and contain user specified values, the final concentrations might not match the calculator specifications. Please select one of the "OtherLiquidMethod" to help reduce this error.
- The user may enable the calculator once to get an idea of the values, and then turn the calculator off to manually change the DSp tab values, if required.
- If the feeder is connected to a sink on another flowsheet, the calculated values are ignored.
- The Feed Calculator maybe different for different species model, please see Alumina 1 vs Alumina 3 for the difference between these two generic species models.
If the Bayer stream has Alumina Particle Size information for use in Precipitation3 unit model, see the relevant quality model documentation for Specific Surface Area (SSA) or Size Distribution (PSD) for display and configuration information.
Global Properties Calculation Method Selection
|Tag / Symbol||Input / Calc||Description|
|Menu Command View - Plant Model - Globals Tab - Bayer Properties:|
|ASatMethod||Rosenberg||Saturated Alumina concentration. See Saturated Alumina Concentration for equations used.|
|RosenbergUser||This uses the same equation as above, but user are able to adjust all the constants in the equation manually.|
|SpecHtMethod||LM_1985||See Heat Capacity Calculations for equations used.|
|Mulloy Donaldson||See Heat Capacity Calculations for equations used.|
|EntropyMethod||Standard||Entropy is calculated by the Standard Species Model using mass weighted mean.|
|LM_1985||Based on the LM1985 specific heat. Only available in Build 137. Please see Entropy Calculations for equation used.|
|SpecHt_UseScale||Tickbox||This allows user to add in a scaling factor for the calculated Bayer Specific Heat value, useful when tuning project to match plant conditions.|
|SpecHt_Factor||Input||This field is only visible if the SpecHt_UseScale tick box is selected. Used to adjust the calculated Bayer Specific Heat value linearly.|
|DensityMethod||MulloyDonaldson||See Density Calculations for equations used.|
|MulloyDonaldsonUser||This uses the same equation as above, but user are able to adjust all the constants in the equation manually.|
|Density_UseScale||Tickbox||This allows user to add in a scaling factor for the Bayer Liquor Density value, useful when tuning project to match plant conditions.|
|Density_Factor||Input||This field is only visible if the Density_UseScale tick box is selected. Used to adjust the calculated Bayer Density value linearly.|
|BPEMethod||Dewey||This is the original method implemented in SysCAD. This method becomes inaccurate in high caustic concentration range.|
|Adamson||This method is more accurate in the high caustic concentration range. |
See Boiling Point Elevation for equations used.
|BPE_UseScaleOffset||Tickbox||This enables a global correction (Scale Factor and Offset) to the calculated BPE value. The resulting BPE has a lower limit 0 degrees.|
|BPE_Factor||Input||This field is only visible if the BPE_UseScaleOffset option is selected. Scale for global correction value for Boiling Point Elevation where final BPE = Calculated BPE * BPE Factor + BPE Offset. Result is limited to a minimum of zero.|
|BPE_Offset||Input||This field is only visible if the BPE_UseScaleOffset option is selected. Offset for global correction value for Boiling Point Elevation where final BPE = Calculated BPE * BPE Factor + BPE Offset. Result is limited to a minimum of zero.|
|ViscMethod||EMA1962||Liquid Viscosity. Limitation apply, see Viscosity for equations used.|
|Alexandrov||Caustic solution viscosity. See Viscosity for equations used. This method is only available in SysCAD 93.|
|OxalateEqMethod||Burnt Island||This is the original method implemented in SysCAD, but should be used with caution.|
|Beckham Grocott||This method is based on synthetic liquor and tuned to plant liquor. |
See Oxalate Equilibrium for equations used. This method is only available from Build 138.
|OxalateEq_UseScaleOffset||Tickbox||This enables a global correction (Scale Factor and Offset) to the calculated Oxalate Equilibrium value. The resulting Oxalate Equilibrium is limited between 0 and 100 g/L Na2C2O4.|
|OxalateEq_Factor||Input||This field is only visible if the OxalateEq_UseScaleOffset option is selected. Scale for global correction value for Oxalate Equilibrium where final OxEq = Calculated OxEq * OxEq Factor + OxEq Offset. Result is limited to a minimum of zero.|
|OxalateEq_Offset||Input||This field is only visible if the OxalateEq_UseScaleOffset option is selected. Offset for global correction value for Oxalate Equilibrium where final OxEq = Calculated OxEq * OxEq Factor + OxEq Offset. Result is limited to a minimum of zero.|
|H2OTestFrac0||Input||This is used to handle very dilute concentration in the stream. If the Water Fraction in the stream is higher than this value, then the stream property will be calculated using the Standard Species Model. The maximum value for this is 99.99%.|
|H2OTestFrac1||Input||This is used to handle very dilute concentration in the stream. If the Water Fraction in the stream is lower than this value, then the stream property will be calculated using the Bayer3 Species model. For water fraction higher than this value but lower than H2OTestFrac0, a proportional calculation will be performed using both the Standard Species Model and the Bayer3 Species model.|
|ShowNa2O_Equiv||Input||Selecting this option will add to the display list of Bayer liquor properties variables expressed on Na2O basis.|
Calculator - Bayer Feed Calculator
|Tag (Long/Short)||Input / Calc||Description||Maximum|
|Bayer Liquor Design Values|
|DefineLiquor||Check Box||If this box is checked, the Feeder will automatically calculate the make-up of the feed stream, based on the variables supplied below.|
|Rqd_A/C / A/C_Reqd||Input||The required ratio of A:C in the Feed stream, where A is Sodium Aluminate NaAl[OH]4 concentration, expressed as grams of Al2O3 /L liquor and C is Caustic Soda concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor.||0.962003767 (MWAl2O3/MWNa2CO3)|
|Rqd_C/S / C/S_Reqd||Input||The required ratio of C:S in the Feed stream, where C is Caustic Soda concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor and S is C+ Na2CO3 concentration, expressed as grams Na2CO3/L liquor. A minimum ratio of 0.1 is applied, however depending on other required concentrations a low A/C ratio can result in an unachievable mixture.||1.0|
|Rqd_C / C_Reqd||Input||The required Caustic Soda concentration in NaOH + NaAl[OH]4, expressed as grams Na2CO3/L liquor @ 25°C.||550.0|
|Rqd_Na2SO4 / Na2SO4_Reqd||Input||Required concentration of Na2SO4 in g/L @ 25°C||550.0|
|Rqd_NaCl / NaCl_Reqd||Input||Required concentration of NaCl in g/L @ 25°C||550.0|
|Rqd_NaF / NaF_Reqd||Input||Required concentration of NaF in g/L @ 25°C. Only appears if NaF is present as a species.||50.0|
|Rqd_Oxalate / Oxalate_Reqd||Input||Required concentration of oxalate in g/L @ 25°C.||550.0|
|Rqd_TOC / TOC_Reqd||Input||Required total organics [Na2C5O7(aq) + Na2C2O4(aq)] concentration in the stream expressed as grams of elemental carbon /L liquor @ 25°C. This determines the non oxalate organics. If the specified oxalate organics result in a higher TOC than specified, non oxalate organics are set to zero.||200.0|
|Rqd_SiO2 / SiO2_Reqd||Input||Required concentration of Na2SiO3 expressed as grams SiO2 /L liquor @ 25°C||550.0|
|The ZeroOtherLiqs tickbox or OtherLiquidMethod list box is only visible when other liquid species in addition to the Required alumina 3 liquid species are present in the project.
|OtherLiquidMethod||Zero Other Liqs||Selecting this method will set all the liquid flows not used by the bayer calculation to zero, this will ensure the output from Bayer DefineLiquor will match the specified concentrations.||N/A|
|Original||(This method is NOT recommended, it is available only for backward compatibility.) User can manually specify composition for the other liquids, the amount of liquids specified will be added to the Total from the Bayer DefineLiquor Calculation. That means, the end result may not match the specified concentrations.||N/A|
|Reduce Bayer Liqs||User can manually specify composition for the other liquids. The calculated bayer liquor composition will be adjusted to offset the user specified values. The end result may not match the specified concentrations.||N/A|
|Reduce Water Only||(This is the recommended method). User can manually specify composition for the other liquids. The calculated water composition will be adjusted to offset the user specified values. The end result will match the specified concentrations.||N/A|
|SolidsDefn||Mass Fraction Solids||The required solids are specified by solids mass fraction.||N/A|
|Total Solids Conc||The required solids are specified by total solids concentration.||N/A|
|SolFracReqd / Rqd_SolFrac||Input||The mass fraction of solids in the feed. The proportion of the different solid species is maintained. If there are no solid species specified then THA is assumed.||0.99|
|SolConcReqd / Rqd_SolConc||Input||The concentration (at 25°C) of solids in the liquor. The proportion of the different solid species is maintained. If there are no solid species specified then THA is assumed.||1600.0|
Bayer Properties Data
A number of these will be deprecated in 9.2 since they are unused or their use has proved confusing. In particular there are a number of organic quantities (TOS, TOOC etc) that fall into this category.
|Tag | Symbol||Input or Calc||Description|
|Bayer Liquor Values @ 25°C|
|A | AluminaConc||Calc||NaAl[OH]4 concentration expressed as Al2O3 @ 25°C. (g/L liquor)|
|C | CausticConc||Calc||NaOH + NaAl[OH]4 concentration, expressed as grams Na2CO3/L liquor @ 25°C.|
|S | SodaConc||Calc||NaOH + NaAl[OH]4 + Na2CO3 concentration, expressed as grams Na2CO3/L liquor @ 25°C.|
|A/C||Calc||Ratio of A to C|
|C/S||Calc||Ratio of C to S|
|Cl/C||Calc||Ratio of Cl to C|
|TOC@25||Calc||Total Organic Carbon concentration, as carbon equivalent. Grams of [Na2C5O7*5 + Na2C2O4*2] / L liquor @ 25°C.|
|TOS@25 (Deprecated)||Calc||Total Organic Soda concentration, grams of [Na2C5O7 + Na2C2O4] / L liquor @ 25°C.|
|SodiumCarbConc||Calc||Sodium Carbonate concentration|
|SolidConc25||Calc||Expressed as grams of solids / L Slurry @ 25°C.|
|FC | FreeCaustic||Calc||Free Caustic, Caustic Concentration excluding the amount asscoiated with NaAl[OH]4, expressed as g/L of Na2CO3.|
|Sulphate*@25||Calc||Sodium Sulphate concentration @ 25°C|
|Chloride*@25||Calc||Sodium Chloride concentration @ 25°C|
|Oxalate*@25||Calc||Oxalate Concentration @ 25°C|
|Silica*@25||Calc||Silicate Concentration as SiO2 @ 25°C|
|Silica/C||Calc||Silica to Caustic ratio times 1000.|
|NaOnCS||Calc||Ratio of Total Sodium (TotalNa) to Caustic Concentration (C)|
|TOS/TOC (Deprecated)||Calc||Ratio of TOS to TOC (Total Organic soda expressed as Na2CO3 / Total Organic Carbon expressed as Carbon)|
|Concentration @ 25°C, as Na2CO3 equivalent|
|Organate@25||Calc||Grams of organic Na2C5O7(l) / L liquor @ 25°C.|
|Oxalate@25||Calc||Grams of oxalate Na2C2O4(l) / L liquor @ 25°C.|
|NaCl@25||Calc||Grams of NaCl(l) / L liquor @ 25°C.|
|Na2SO4@25||Calc||Grams of Na2SO4(l) / L liquor @ 25°C.|
|TotalNa@25||Calc||Total sodium as per TNa Equation in Model Theory section, but expressed as g/L liquor @ 25°C.|
|Other properties @ 25°C|
|LRho25 | LiquidDensity@25||Calc||The liquor density @ 25°C.|
|SLRho25 | SlurryDensity@25||Calc||The slurry density @ 25°C.|
|LQv25 | LVolFlow25||Calc||Liquor Volumetric Flowrate @25°C.|
|SLQv25 | SLVolFlow25||Calc||Slurry Volumetric Flowrate @25°C.|
|Bayer Liquor Values @ 25 °C, as Na2O Equivalent |
NOTE: This group of variables is only visible if the View|PlantModel|Globals - ShowNa2O_Equiv tickbox is selected.
|C_Na2O||Calc||NaOH + NaAl[OH]4 concentration, expressed as grams Na2O/L liquor @ 25°C.|
|S_Na2O||Calc||NaOH + NaAl[OH]4 + Na2CO3 concentration, expressed as grams Na2O/L liquor @ 25°C.|
|TotalNa@25_Na2O||Calc||Total Sodium, expressed as grams Na2O/L Liquor @ 25°C.|
|RP | A/C_Na2O||Calc||Ratio of A : C expressed as Na2O.|
|RPSat | A/C_Sat_Na2O||Calc||Ratio of ASat : C@25 expressed as Na2O.|
|Bayer Liquor Values @ Temperature|
|A@T | AluminaConcT||Calc||Al2O3 concentration @ Temperature (g/L liquor)|
|C@T | CausticConcT||Calc||NaOH + NaAl[OH]4 concentration, expressed as grams Na2CO3/L liquor @ Temperature.|
|S@T | SodaConcT||Calc||NaOH + NaAl[OH]4 + Na2CO3 concentration, expressed as grams Na2CO3/L Liquor @ Temperature.|
|TOC@T||Calc||Total organic carbon concentration as Carbon equivalent. Grams of [Na2C5O7*5 + Na2C2O4*2] / L liquor @ Temperature.|
|SodiumCarbConc@T||Calc||Sodium Carbonate concentration @ Temperature.|
|SolidConc@T||Calc||Expressed as grams of solids / L Slurry @ Temperature.|
|BPE@T | BoilPtElev||Calc||Boiling Point Elevation calculated as a function of stream temperature.
Note: this differs to the BPE value displayed under the Saturation section as BPE is calculated as a function of pressure. The two values and BPE@P will be the same if the stream is at saturated conditions.
|BPE@P | BoilPtElev@P||Calc||Boiling Point Elevation calculated as a function of stream pressure.
Note: this is the same as the BPE value displayed under the Saturation section. BPE@T will be the same as BPE@P if the stream is at saturated conditions.
|Bayer Liquor Values @ T, as Na2O Equivalent|
NOTE: This group of variables is only visible if the View|PlantModel|Globals - ShowNa2O_Equiv tickbox is selected.
|CausticConc@T_Na2O||Calc||NaOH concentration, expressed as grams Na2O/L liquor @ Temperature.|
|SodaConc@T_Na2O||Calc||NaOH plus Na2CO3 concentration, expressed as grams Na2O/L liquor @ Temperature.|
|TotalNa@T_Na2O||Calc||Total Sodium, expressed as grams Na2O/L Liquor @ Temperature.|
|Bayer Liquor Solubility Properties @ T|
|ASat | A_Saturation||Calc||The saturated Alumina concentration @ stream temperature. (Note: As described in Model Theory, concentrations used in the correlation are referenced to 25°C).|
|AConcEquil | AConcEquilibrium||Calc||Alumina Concentration (A) at Equilibrium, ie accounting for changes in composition to liquor if equilibrium saturation is reached.|
|CConcEquil | CConcEquilibrium||Calc||Caustic Concentration (C) at Equilibrium, ie accounting for changes in composition to liquor if equilibrium saturation is reached.|
|A/CSat | A/C_Saturation||Calc||The ratio of ASat : C. (Note: Concentrations used in ASat correlation are referenced to 25°C, so ratio is ASat : C@25).|
|SSN_Ratio||Calc||The ratio of A : ASat which is the same as ratio of fields 'A/C' : 'A/CSat'. (Note: Concentrations used in ASat correlation are referenced to 25°C, so ratio is A@25 : ASat).|
|A_ASat_Diff||Calc||The difference between Alumina Concentration @ temperature and Alumina Saturation Concentration. So result is fields 'A@T' - 'ASat'.|
|I | IonicStrength||Calc||The Ionic strength. See model theory under Alumina Saturation for equation.|
|OxalateEq | OxalateEquilibrium||Calc||The Oxalate Equilibrium value. See Model Theory for equation.|
|THA.Qm | THAMassFlow||Calc||The mass flowrate of THA - Al[OH]3(s).|
|THA.Rho | THADens||Calc||The density of THA - Al[OH]3(s).|