COMMODITY_GROUP GetKCoeffsGroup(COMMODITY_GROUP grp, double api60)
{
if (grp != COMMODITY_GROUP.GENERALIZED_REFINED_PRODUCT)
{
return(grp);
}
// Try to match density range
var uom = uoms["api"];
COMMODITY_GROUP ret = COMMODITY_GROUP.ANY;
foreach (var limKv in uom.Limits)
{
if (((int)limKv.Key) >= 100) // Limit to refined product subgroups
{
if (limKv.Value.ValueIsWithin(api60))
{
// Found it!
ret = limKv.Key;
break;
}
}
}
if (ret == COMMODITY_GROUP.ANY)
{
throw (new ArgumentException("Density is not in the range of any of the Generalized Refined Products"));
}
return(ret);
}
// API 12.1 - Tank Roof Corrections
public double GetBarrelsDueToTankRoof(COMMODITY_GROUP grp, double api60, double tempF, double presPsi = 0, double vapPresPsi = 0, double roofWgtLb = 0, double bblPerApi = 0, double refApi = 0)
{
// Get CTPL
double CTPL = GetCTPLFromApiDegFPsig(grp, api60, tempF, presPsi, vapPresPsi);
return(GetBarrelsDueToTankRoof(api60, CTPL, roofWgtLb, bblPerApi, refApi));
}
void checkRange(double val, string units, COMMODITY_GROUP grp = COMMODITY_GROUP.ANY)
{
// Validate and get UoM that contains the limits
UnitOfMeasure uom = null;
if (!uoms.TryGetValue(units.ToLower(), out uom))
{
throw (new ArgumentException("Units {0} not recognized or supported"));
}
// If not limits defined, there is nothig to check
if (uom.Limits == null || uom.Limits.Count < 1)
{
return;
}
bool isLiquidGas = (grp == COMMODITY_GROUP.LPG_NGL);
bool isGeneralizedRefinedProduct = ((int)grp >= 100);
// Ignore commodity if limits are for ANY commodity
if (!isLiquidGas && uom.Limits.ContainsKey(COMMODITY_GROUP.ANY))
{
try
{
uom.Limits[COMMODITY_GROUP.ANY].CheckLimits(val);
}
catch (ArgumentOutOfRangeException e)
{
throw(new ArgumentOutOfRangeException(String.Format("{0} with units={1}", e.Message, units)));
}
return;
}
// Check limit for commodity
ValueLimit limit = null;
var type = grp;
if (isGeneralizedRefinedProduct)
{
type = COMMODITY_GROUP.GENERALIZED_REFINED_PRODUCT; // Needed to allow density variations within refined products group
}
if (!uom.Limits.TryGetValue(type, out limit))
{
throw (new ArgumentException("Limits for commodity group {0} not supported"));
}
try
{
limit.CheckLimits(val);
}
catch (ArgumentOutOfRangeException e)
{
throw (new ArgumentOutOfRangeException(String.Format("{0} with units={1} and commodity group={2}", e.Message, units, grp)));
}
return;
}
// Convenient method to handle all in a single call
public double GetCTPLFromApiDegFPsig(COMMODITY_GROUP grp, double api60, double tempF, double?presPsig = null, double?vapPress = null)
{
if (grp == COMMODITY_GROUP.LPG_NGL)
{
if (vapPress == null)
{
vapPress = GetVapPressPsia(api60, tempF) + Conversions.pressAtmPsi; // From API 11.2.5 estimation
}
return(GetCTPLFromAPIDegFPsigLiqGas(api60, tempF, presPsig == null ? 0 : presPsig.Value, vapPress.Value));
}
return(GetCTPLFromApiDegFPsigNONLiqGas(grp, api60, tempF, presPsig == null ? 0 : presPsig.Value));
}
// API 11.1. - Equation (7)
public double GetDensityFromDensity60(COMMODITY_GROUP grp, double api60, double tempF, double presPsi = 0, double vapPresPsi = 0)
{
if (tempF == 60.0 && presPsi == 0.0)
{
return(api60);
}
// Get CTPL
double CTPL = GetCTPLFromApiDegFPsig(grp, api60, tempF, presPsi, vapPresPsi);
// Use to computed API - Remember API is inverse of density
return(api60 / CTPL);
}
// Section 11.1.6.1 Step 3 Ki Table
public KCoeffs GetKCoeffs(COMMODITY_GROUP cgroup, double api60 = 0.0)
{
// If density is passed, try to match commodity group to density
if (api60 > 0.0)
{
cgroup = GetKCoeffsGroup(cgroup, api60);
}
KCoeffs coeffs = null;
if (!kCoeffs.TryGetValue(cgroup, out coeffs))
{
throw (new ArgumentException(String.Format("Coefficients for COMMODITY_GROUP {0} not found", cgroup)));
}
return(coeffs);
}
// Section 11.1.6.1 CTPL (commonly known as VCF)
double GetCTPLFromApiDegFPsigNONLiqGas(COMMODITY_GROUP grp, double api60, double tempF, double presPsig = 0)
{
// Step 1 - Check range for density,temperature and pressure
checkRange(api60, "API", grp);
checkRange(tempF, "degF");
if (presPsig < 0)
{
presPsig = 0;
}
checkRange(presPsig, "psig");
KCoeffs coeffs = GetKCoeffs(grp, api60);
// Step 2 and 3 - Get corrected temp and density at ITP68 basis
double tempITPS68 = Conversions.TempITS90toITPS68(tempF, "degF");
double densITSP68 = Conversions.Api60ITS90tokgm3ITPS68(api60, coeffs); // kg/m3
// Step 4 - Compute coefficient of thermal expansion
double thermExpCoeff60 = GetThermExpCoeff60(densITSP68, coeffs);
// Step 5 - Compute temperature correction factor
double CTL = GetCTL(thermExpCoeff60, tempITPS68);
double CPL = 1.0; // No compensations
// If not ATM pressure correct for pressure
if (presPsig > 0)
{
// Step 6 - Compute compressibility factor
double Fp = GetCompressFactor(densITSP68, tempITPS68);
// Step 7 - Compute pressure correction
CPL = GetCPL(Fp, presPsig);
}
// Step 8
double CTPL = CTL * CPL;
return(RoundUpAPI11_1(CTPL, "CTPL"));
}
public double GetDensity60FromDensity(COMMODITY_GROUP grp, double api, double tempF, out double CTPL, double presPsi = 0, double vapPresPsi = 0)
{
CTPL = 1.0;
if (tempF == 60.0 && presPsi == 0.0)
{
return(api);
}
// Guess desired initially set to the same as input density
double api60 = api;
double apiGuessed = api;
// Iterate
int i = 0;
do
{
if (i > MAXITERATIONS)
{
throw(new OperationCanceledException("Maximum iterations {0} have been exceeded when trying to compute api60 from api"));
}
api60 = api60 - 0.61803 * (apiGuessed - api); // Using golden ratio for simplicity
// Get CTPL using guessed number
CTPL = GetCTPLFromApiDegFPsig(grp, api60, tempF, presPsi, vapPresPsi);
// Get guessed api
apiGuessed = api60 / CTPL;
i++;
}while (CTPL * Math.Abs(api - apiGuessed) > 0.1 * uoms["api"].Precision); // A little better than precision
// Check ranges
checkRange(api60, "api", grp);
// Return reached at api60
return(api60);
}
// API 11.2.4 Section 5.1.1.3
// Temperature compensation CTL
public double GetCTLLiqGas(double tempF, double api60)
{
// Step T24/3
// Check Density and Temperature range
COMMODITY_GROUP grp = COMMODITY_GROUP.LPG_NGL;
checkRange(api60, "API", grp);
checkRange(tempF, "degF", grp); // Group must be specified
// Step T24/2
// Convert temp to Kelvin and roundup
tempF = RoundUp(tempF, -1);
double Tx = Conversions.DegFtoDegK(tempF);
// Convert to relative density and roundup
double relDens60 = Conversions.APItoSG(api60);
relDens60 = RoundUp(relDens60, -4);
// Step T24/4
// Chose reference fluid subscripts (1,2)
LiqGasProperties f1 = null;
LiqGasProperties f2 = null;
LiqGasProperties prev = null;
foreach (var lgProp in lgProps)
{
if (prev != null)
{
if (lgProp.Value.relDens60 >= relDens60)
{
f2 = lgProp.Value;
f1 = prev;
break;
}
}
prev = lgProp.Value;
}
if (f2 == null || f1 == null)
{
throw (new ArgumentException(String.Format("Relative density {0} is out of the range of API 11.2.4 Table 1", api60)));
}
// Step T24/5
// Compute interpolation variable
double delta = (relDens60 - f1.relDens60) / (f2.relDens60 - f1.relDens60);
// Step T24/6
// Compute interpolated critical temperature
double Tc = f1.tempCritK + delta * (f2.tempCritK - f1.tempCritK);
// Step T24/7
// Compute reduced temperature ratio
double Trx = Tx / Tc;
if (Trx > 1)
{
throw (new ArgumentException(String.Format("Temperature {0} will result in supercritical conditions which are not supported by this computation", tempF)));
}
// Step 24/8
// Compute reduced temperature at 60F
double t60K = Conversions.DegFtoDegK(60);
double Tr60 = t60K / Tc;
// Step 24/9
// Compute scaling factor
double h2 = (f1.comprFactCrit * f1.densCrit) / (f2.comprFactCrit * f2.densCrit);
// Step 24/10
// Compute saturation density of both fluids at 60F
double dens60_1 = getSatDensityAtTemp(Tr60, f1);
double dens60_2 = getSatDensityAtTemp(Tr60, f2);
// Step 24/11
// Calculate interpolating factor
Func <double, double, double> ratio = (dens1, dens2) => dens1 / (1 + delta * (dens1 / (h2 * dens2) - 1));
double X = ratio(dens60_1, dens60_2);
// Step 24/12
// Opbtain saturation density of both fluids at Trx
double densX_1 = getSatDensityAtTemp(Trx, f1);
double densX_2 = getSatDensityAtTemp(Trx, f2);
// Step 24/13
// Obtain CTL
double CTL = ratio(densX_1, densX_2) / X;
return(CTL);
}
