Calculators›NGL Recovery Optimization
📊

NGL Recovery Optimization

GPSA 14th Ed. · Plant Processing of Natural Gas · Ethane, Propane & C4+ Recovery

Advertisement
NGL Recovery Optimization Calculator
Material balance model for cryogenic and refrigeration-based NGL recovery. Calculates liquid yields, residue gas properties, and plant economics based on GPSA component data.

Feed Gas Composition

MMSCFD
mol%
mol%
mol%
mol%
Balance assumed to be methane + inerts

Operating Mode

Turboexpander + External Refrigeration Cryogenic operation: -120°F to -150°F demethanizer. Typical for petrochemical feedstock markets.
%
%
%

Product Pricing (Mont Belvieu basis)

$/gal
$/gal
$/gal
$/gal
$/MMBtu
Leave at 0 for volume-only calculation

📚 Learn the Theory

Understand ngl recovery optimization principles, calculations, and industry applications

Read Engineering Guide →

Process Selection Guide

Process Temp C₂ Rec C₃ Rec
GSP/SCORE -140°F 95% 99%
Turboexpander -120°F 85% 98%
JT Valve -80°F 40% 90%
Mech Refrig -40°F 15% 85%
Lean Oil Ambient 5% 70%
Liquid Yield Factors (gal/MSCF)
ComponentFactor
Ethane26.69
Propane27.46
n-Butane31.44
i-Butane32.79
n-Pentane36.09
Source: GPSA 14th Ed., Table 23-2

Residue Gas Specifications

Typical pipeline tariff requirements:

  • Heating Value: 950–1,100 BTU/SCF
  • Wobbe Index: 1,310–1,390
  • Hydrocarbon Dewpoint: < 15°F @ 800 psig
  • CO₂: < 2 mol%
  • H₂S: < 4 ppmv
Residue HHV Calculation
HVmix = Σ(yi × HVi)

Economic Considerations

  • Frac Spread: NGL value vs gas shrinkage determines optimal recovery
  • Ethane Rejection: Common when C₂ price < 35% of propane
  • Mode Flexibility: Plants designed for 2-3 operating modes add optionality value
  • Operating Cost: ~$0.10-0.30/gal NGL for cryogenic plants
Rule of Thumb: Rich gas (>3 GPM) typically justifies turboexpander; lean gas (<1.5 GPM) may favor JT or refrigeration only.

Technical Notes

Calculation Methodology

This calculator uses component material balance with GPSA liquid yield factors to estimate NGL production from specified recovery targets. Conversion from gas volume (MSCF) to liquid volume (gallons) uses the relationship:

GPD = MMSCFD × 1000 × mol% × Recovery% × (gal/MSCF)

where gal/MSCF = (1000/379.5) × MW / ρliquid

Assumptions & Limitations

  • Ideal gas behavior (379.5 SCF/lbmol @ 60°F, 14.696 psia)
  • Feed gas balance assumed to be methane
  • Butanes modeled as 40/60 iC₄/nC₄ mix
  • C₅+ recovery fixed at 99.9%
  • No CO₂, N₂, or H₂S correction
  • Heating values are gross (HHV) basis

References

  • GPSA Engineering Data Book, 14th Edition (SI)
  • Campbell, J.M., "Gas Conditioning and Processing", Vol. 2
  • Arnold & Stewart, "Surface Production Operations", Vol. 2
  • API Technical Data Book
Advertisement
Advertisement

Related Calculators

💨

Gas Density

Calculate gas density with compressibility
💧

Pipeline Hydraulics

Calculate total pipeline pressure drop
📏

Line Sizing

Optimize pipeline diameter selection
📊

Pipe Volume

Calculate pipeline internal volume