Package 'ISO6976.2016'

Description

Calculates calorific values (gross and net, molar, mass and volumetric bases), density, relative density, and Wobbe indices together with their standard uncertainties from natural gas composition, following ISO 6976:2016 "Natural Gas — Calculation of calorific values, density, relative density and Wobbe indices from composition".

Details

Uncertainty propagation is implemented according to Annex B of that standard (variance-covariance method).

**Application restrictions (ISO 6976:2016 §5):** * Combustion temperature: 0, 15, 15.55 (60 °F), 20, or 25 °C. * Volume reference temperature: 0, 15, 15.55 (60 °F), or 20 °C. * Reference pressure: 90–110 kPa. * Compression factor Z must be > 0.9.

Author(s)

Rüdiger Forster [email protected]

References

ISO 6976:2016 "Natural Gas — Calculation of calorific values, density, relative density and Wobbe indices from composition".

See Also

Useful links:

• https://github.com/RuedigerForster/ISO_6976

• Report bugs at https://github.com/RuedigerForster/ISO_6976/issues

Description

Computes all combustion and volumetric properties of a natural gas mixture together with their standard (or expanded) uncertainties, following the method and tables of ISO 6976:2016 and the uncertainty propagation formulae of its Annex B.

Usage

calculateProperties(
  compositionArray,
  uncertaintyArray,
  correlationMatrix,
  combustionTemperature = 25,
  volumeTemperature = 15,
  pressure = 101.325,
  coverage = 1
)

Arguments

Value

A named list with the following elements (all numeric scalars):

| Name | Description | Unit | |———–|—————————————————–|————| | M | Molar mass | kg/kmol | | Z | Compression factor | — | | G_o | Ideal-gas relative density | — | | D_o | Ideal-gas density | kg/m³ | | G, u_G | Real-gas relative density and uncertainty | — | | D, u_D | Real-gas density and uncertainty | kg/m³ | | Hcg, u_Hcg| Molar gross calorific value and uncertainty | kJ/mol | | Hcn, u_Hcn| Molar net calorific value and uncertainty | kJ/mol | | Hmg, u_Hmg| Mass-basis gross calorific value and uncertainty | MJ/kg | | Hmn, u_Hmn| Mass-basis net calorific value and uncertainty | MJ/kg | | Hvg_o, u_Hvg_o | Ideal-gas vol. gross CV and uncertainty | MJ/m³ | | Hvn_o, u_Hvn_o | Ideal-gas vol. net CV and uncertainty | MJ/m³ | | Hvg, u_Hvg| Real-gas vol. gross CV and uncertainty | MJ/m³ | | Hvn, u_Hvn| Real-gas vol. net CV and uncertainty | MJ/m³ | | Wg_o | Ideal-gas gross Wobbe index | MJ/m³ | | Wn_o | Ideal-gas net Wobbe index | MJ/m³ | | Wg, u_Wg | Real-gas gross Wobbe index and uncertainty | MJ/m³ | | Wn, u_Wn | Real-gas net Wobbe index and uncertainty | MJ/m³ |

References

ISO 6976:2016 "Natural Gas — Calculation of calorific values, density, relative density and Wobbe indices from composition"

See Also

GasComponents, componentNames

Examples

data("example1")
res <- calculateProperties(example1$fractionArray, example1$uncertaintyArray,
                           example1$correlationMatrix,
                           combustionTemperature = 15, volumeTemperature = 15)
res$M      # molar mass [kg/kmol]
res$Hvg    # real-gas vol. gross CV [MJ/m^3]
res$u_Wg   # standard uncertainty of gross Wobbe index

Description

Return the index of a gas component by name

Usage

componentIndex(name)

Arguments

Value

Integer index (1–60) into the composition vector.

Description

Return the name of a gas component by index

Usage

componentName(index)

Arguments

Value

Character string with the English component name.

Description

Returns the ordered character vector of all 60 natural gas components recognised by ISO 6976:2016 (Table A.2). The position of each name corresponds to the index used in compositionArray, uncertaintyArray, and correlationMatrix.

Usage

componentNames()

Value

Character vector of length 60.

See Also

componentIndex, componentName

Description

A five-component natural gas mixture from Annex D.2 of ISO 6976:2016. Non-zero components: methane, ethane, propane, nitrogen, carbon dioxide.

Format

A named list with three elements:

fractionArray

Numeric vector (length 60) of mole fractions [mol/mol].

uncertaintyArray

Numeric vector (length 60) of standard uncertainties [mol/mol].

correlationMatrix

60×60 identity correlation matrix.

Source

ISO 6976:2016 Annex D.2, Table D.2.

Description

An eleven-component natural gas mixture including water vapour from Annex D.3 of ISO 6976:2016.

Format

A named list with three elements (same structure as example1).

Source

ISO 6976:2016 Annex D.3, Table D.3.

Description

An eleven-component natural gas mixture from Annex D of ISO 6976:2016 with an identity correlation matrix (no inter-component correlations). Used to verify calculations at 15/15 °C and 25/0 °C.

Format

A named list with three elements (same structure as example1).

Source

ISO 6976:2016 Annex D.

Description

The same eleven-component mixture as example3 but with a full inter-component correlation matrix from a GC calibration covariance analysis, as given in Annex D of ISO 6976:2016.

Format

A named list with three elements (same structure as example1).

Source

ISO 6976:2016 Annex D (extended correlation case).

Description

R6 class for natural gas composition input

R6 class for natural gas composition input

Details

GasComponents holds the mole fractions, their standard uncertainties, and the inter-component correlation matrix for a natural gas mixture. All three quantities are required as input to calculateProperties.

Components are identified either by their integer index (1–60, matching ISO 6976:2016 Table A.2) or by English name (see componentNames).

Public fields

Methods

Public methods

• GasComponents$new()

• GasComponents$getFraction()

• GasComponents$getUncertainty()

• GasComponents$getCorrelation()

• GasComponents$setFraction()

• GasComponents$setUncertainty()

• GasComponents$setCorrelation()

• GasComponents$setFractionArray()

• GasComponents$setUncertaintyArray()

• GasComponents$setCorrelationMatrix()

• GasComponents$clone()

Method new()

Create a new GasComponents object. Initialises fractions and uncertainties to zero and correlations to the 60x60 identity matrix.

Usage

GasComponents$new()

Method getFraction()

Get the mole fraction of a single component.

Usage

GasComponents$getFraction(name)

Arguments

Returns

Numeric scalar.

Method getUncertainty()

Get the standard uncertainty of a single component.

Usage

GasComponents$getUncertainty(name)

Arguments

Returns

Numeric scalar.

Method getCorrelation()

Get the correlation between two components.

Usage

GasComponents$getCorrelation(name1, name2)

Arguments

Returns

Numeric scalar in \[-1, 1\].

Method setFraction()

Set the mole fraction of a single component.

Usage

GasComponents$setFraction(name, value)

Arguments

Method setUncertainty()

Set the standard uncertainty of a single component.

Usage

GasComponents$setUncertainty(name, value)

Arguments

Method setCorrelation()

Set the correlation between two components.

Usage

GasComponents$setCorrelation(name1, name2, value)

Arguments

Method setFractionArray()

Set all mole fractions at once.

Usage

GasComponents$setFractionArray(x)

Arguments

Method setUncertaintyArray()

Set all uncertainties at once.

Usage

GasComponents$setUncertaintyArray(u)

Arguments

Method setCorrelationMatrix()

Set the full correlation matrix.

Usage

GasComponents$setCorrelationMatrix(r)

Arguments

Method clone()

The objects of this class are cloneable with this method.

Usage

GasComponents$clone(deep = FALSE)

Arguments

Description

Calculate all ISO 6976:2016 properties and their uncertainties

Usage

iso6976_calc(x, u_x, r_x, t1, t2, p2, k = 1)

Arguments

Value

Named list of properties and uncertainties