Optional inputs

In addition to the mandatory inputs required for the various flash calculations, three additional inputs may also be present to control the calculation or for requesting additional data in the output. These are:-

• included/excluded solids

• optional properties

• output units

In this example, let's assume the chemistry model file contains H2O, NACL, CO2 and BENZENE as inflows and is using the MSE thermodynamic framework.

include or exclude solid species from precipitating

OLI flash computations by default account for the formation of all solid species in the chemistry model. However, users can choose a subset of solid species in the computation by specifying them in the params.excludedSolids or params.includedSolids array. Example input and description are given below.

Note: Solids must be specified using the fully qualified tag. This is returned as the trueName when using the Chemistry Information API.

exclude solids

"excludedSolids": [
            "NAOH.2H2O",
            "NAOH.4H2O",
            "NACLPPT"
        ]

exclude all solids

"includedSolids": [] 

include solids

"includedSolids": [
            "NAOH.2H2O",
            "NAOH.4H2O",
            "NACLPPT"
        ]

params	type	description
excludedSolids	[string]	list of excluded solid species in the flash computation
includedSolids	[string]	list of included solid species in flash computation, if an empty array is specified, all solids will be excluded

params.excludedSolids and params.includedSolids cannot be specified at the same time.

Optional properties

After the equilibrium solution is obtained, the user has the option to specify a number of optional properties to be computed along with this output. These can be turned on or off using a Boolean flag (true/false) in the params.optionalProperties object. Example input and description is given below

{
    "params": {
        ...<snip>...
        "optionalProperties": {
            "electricalConductivity": true,
            "viscosity": true,
            "selfDiffusivity": true,
            "heatCapacity": true,
            "thermalConductivity": true,
            "surfaceTension": true,
            "interfacialTension": true,
            "prescalingTendencies": true
        }
    }
}

params.optionalProperties	type	desc
electricalConductivity	bool	Electrical conductivity of the liquid phase
viscosity	bool	Viscosity for any liquid or gas phases
selfDiffusivityAndMobility	bool	Self diffusivity and mobility for any liquid or gas phases
heatCapacity	bool	Heat capacity for any phases
thermalConductivity	bool	Thermal conductivity for any phases
surfaceTension	bool	Surface tension for any liquid phases
interfacialTension	bool	Interfacial tension between liquid1 and liquid2 phases
volumeStdConditions	bool	liquid1, liquid2, and vapor phase volume at standard conditions
prescalingTendenciesEstimated	bool	prescaling tendencies of solids using the estimated method
prescalingIndexEstimated	bool	prescaling indices of solids using the estimated method
prescalingTendenciesRigorous	bool	prescaling tendencies of solids using the rigorous method
prescalingIndexRigorous	bool	prescaling indices of solids using the rigorous method
scalingTendencies	bool	scaling tendencies of solids
scalingIndex	bool	scaling indices of solids
hardness	bool	hardness of liquid1 phase
ionicStrengthXBased	bool	x-based ionic strength of any liquid phases
ionicStrengthMBased	bool	m-based ionic strength of any liquid phases
totalDissolvedSolids	bool	total dissolved solids in the liquid1 phase
vaporToInflowMoleFraction	bool	vapor to inflow mole fraction
partialPressure	bool	vapor phase partial pressures of all species
vaporDiffusivityMatrix	bool	vapor diffusivity matrix
entropyStream	bool	entropy of stream for all phases
entropySpecies	bool	entropy of each species for all phases
entropyStreamStandardState	bool	entropy of stream at standard state for all phases
entropySpeciesStandardState	bool	entropy of each species at standard state for all phases
gibbsEnergyStream	bool	Gibbs free energy of stream for all phases
gibbsEnergySpecies	bool	Gibbs free energy of each species for all phases
gibbsEnergyStreamStandardState	bool	Gibbs free energy of stream at standard state for all phases
gibbsEnergySpeciesStandardState	bool	Gibbs free energy of each species at standard state for all phases
activityCoefficientsMBased	bool	m-based activity coefficients of each species for all liquid phases
activityCoefficientsXBased	bool	x-based activity coefficients of each species for all liquid phases
fugacityCoefficients	bool	fugacity coefficients of each species for liquid2 and vapor phases
vaporFugacity	bool	fugacities of each species for vapor phase
kValuesXBased	bool	x-based K-values for all equilibrium reactions
kValuesMBased	bool	x-based M-values for all equilibrium reactions
materialBalanceGroup	bool	material balance group compositions for all phases

params.optionalProperties.volumeStdConditions calculate liquid1, liquid2, and vapor phase volume at default standard conditions, which can be specified in here.

params.optionalProperties.scalingInductionTime calculates induction time for scaling solids. Additional inputs are needed for this calculation and explained here. This property is only supported for MSE and MSE-SRK thermodynamic properties.

Scaling Induction Time

Induction time is estimated based on the supersaturation level of the scaling solid. Therefore, such solids need to be excluded to calculate their induction times, as specified below.

{
    "params": {
        ...<snip>...
        "inductionTimeExcludedSolids": [
            "ARAGONITEPPT",
            "BACO3PPT",
            "BASO4PPT",
            ...<snip>...
        ]
    }
}

Standard conditions

Standard conditions can be specified to calculate the optional property params.optionalProperties.volumeStdConditions.

{
    "params": {
        ...<snip>...
        "standardConditions": [
            {
                "phase": "oil",
                "temperature": {
                    "unit": "°C",
                    "value": 15.5556
                },
                "pressure": {
                    "unit": "atm",
                    "value": 1.0
                }
            },
            {
                "phase": "gas",
                ...<snip>...
            },
            {
                "phase": "aqueous",
                ...<snip>...
            }
        ]
    }
}

params.standardConditions[i]	type	description
phase	string	name of the phase, which can be oil, aqueous, or gas
temperature	valueObject	standard condition temperature
pressure	valueObject	standard condition temperature

phase	default temperature in °C	default pressure in atm
oil	15.5556	1.0
gas	16.8500	1.48038
aqueous	25.0	1.0

Output units

Users can optionally specify units of the output values in the Stream output. More details are explained in User-defined output unit set.

params.unitSetInfo is optional. OLIEngine default units will be used if this object is not specified.

Molecular conversion

There are two types of speciation information in the stream output: true concentration and molecular concentration. While the true concentration reflects the speciation of the real species which is unique, the molecular concentration is one of many representations for the true species in molecular/inflow forms. Users have the option to specify three weighting methods for this molecular conversion:

{
    "params": {
        ...<snip>...
        "molecularConversion": {
            "option": "userSpecified",
            "weightFactors": {
                "NAOH": 50.0,
                "CACO3": 10.0
            }
        }
    }    
}

molecularConversion.option	description
automatic	no weightage preference
inflowRateBased	weightage is proportional to input inflow values
userSpecified	user-specified weight factors for any inflows

molecularConversion.weightFactors object is only specified when molecularConversion.option is "userSpecified". The weight factor of each inflow is specified as "inflow_name": number, in the range from 0.0 to 100.0

params.molecularConversion object is optional. By default, "inflowRateBased" option is used.

JSON input (sample)

Below is the sample JSON input covering all three options using isothermal flash as an example.

{
    "method": "oliengine.isothermalFlash",
    "params": {
        "temperature": {
            "value": 40.0,
            "unit": "°C"
        },
        "pressure": {
            "value": 1.5,
            "unit": "atm"
        },
        "inflows": {
            "unit": "mol",
            "values": {
                "H2O": 50.0,
                "BENZENE": 10.0,
                "CH4": 20.0,
                "NAOH": 35.0
            },
            "totalAmount":
            {
                "value": 3402.68,
                "unit": "g"
            }
        },
        "excludedSolids": [
            "NAOH.2H2O",
            "NAOH.4H2O"
        ],
        "optionalProperties": {
            "electricalConductivity": true,
            "viscosity": true,
            "selfDiffusivity": true,
            "heatCapacity": true,
            "thermalConductivity": true,
            "surfaceTension": true,
            "interfacialTension": true,
            "prescalingTendencies": true
        },
        "unitSetInfo": {
            "inflows": "mol",
            "total": "g",
            "liq1_phs_comp": "mol/mol",
            ...<snip>...
            "hardness": "mg/L of Mg+2 and Ca+2",
            "tic": "mol C/L"
        }
}