Calculators›J-T Valve Cooling
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Joule-Thomson Valve Cooling Calculator

Natural Gas Processing · J-T Cooling Effect · Enhanced Correlations

Professional Joule-Thomson Cooling Calculator
Calculates temperature drop across pressure reduction valves using peer-reviewed correlations: J-T coefficient from ACS Omega (2021), hydrate temperature from Katz (1945) and Towler-Mokhatab (2005) averaged.
For general pipeline heat loss, use the Temperature Drop Calculator →

Upstream Conditions

psia
°F
MMSCFD

Downstream Conditions & Gas Properties

psia
-
Typical values: 0.55-0.65 lean gas, 0.65-0.75 medium, 0.75-0.85 rich gas

Hydrate Prevention Analysis

lb/MMSCF
Auto-calculation uses simplified gravity-based correlation at outlet pressure. For critical applications, manually input hydrate temperature from Katz charts or process simulator.

📚 Learn the Theory

Understand J-T cooling principles, hydrate formation, and NGL recovery applications

Read Engineering Guide →

🔬 Rigorous Calculation Method

This calculator uses peer-reviewed correlations from industry literature for professional-grade accuracy.

Technical References

Pseudo-Critical Properties
Sutton (1985) - SPE 14265
J-T Coefficient
ACS Omega (2021) - Reduced property correlation with Cp
Hydrate Temperature
Katz (1945) + Towler-Mokhatab (2005) averaged
Step-Wise Integration
Incremental calculation for ΔP > 150 psi with varying μJT and Cp
J-T Coefficient Formula:
μJT = f(Pr, Tr) × (Tpc/Ppc) × (1/Cp)
Where f(Pr,Tr) = 2.343×Tr-2.04 - 0.071×Pr + 0.0568
Hydrate Temperature Correlations:
Katz (1945): T = -54.5 + 13.1×ln(P) + 40×γ (fitted to GPSA charts)
Towler-Mokhatab (2005): T = 13.47×ln(P) + 34.27×ln(γ) - 1.675×ln(P)×ln(γ) - 20.35

📊 Reference Data & Accuracy

Typical J-T Coefficients

Pure Methane 6.5-7.0°F per 100 psi @ 80°F, 500 psia
Lean Gas (SG 0.6) 6-8°F per 100 psi
Medium Gas (SG 0.7) 5-7°F per 100 psi
Rich Gas (SG 0.8) 4-6°F per 100 psi
ℹ️ Effect decreases with higher temperature and pressure (lower Tr, higher Pr)

Accuracy & Limitations

✓ J-T Coefficient: ±5-10% using rigorous reduced property correlation
✓ Hydrate Temperature: ±2-4°F using averaged Katz + Towler-Mokhatab
✓ Optimal Range: SG 0.55-0.90, P 100-2000 psia, T 0-150°F, single-phase gas
✗ Not Valid For: H₂/He, very sour gas (>10% acid gases), or two-phase flow
⚠️ Critical Design: Verify with process simulator (HYSYS, ProMax, PVTSim) using rigorous EOS (SRK, PR, GERG-2008)

✓ Appropriate Use Cases

• Preliminary design and feasibility studies
• Operating parameter screening and troubleshooting
• Educational and training purposes
• Quick engineering checks and estimates

⚙️ Applications & Design Guidelines

Common Applications

🏭 Pressure letdown stations and city gate regulation
🛢️ Wellhead choke valves in production
❄️ Turbo-expander inlet conditions (cryogenic NGL plants)
📍 Pipeline pressure regulation and metering stations
⚗️ Gas processing plant feed conditioning

Critical Design Considerations

🧊 Hydrate Prevention
Maintain 10-20°F margin above hydrate point
🔥 Preheat Options
Line heaters, heat exchangers for high ΔP cases
💧 Inhibitor Injection
Methanol or glycol if T₂ approaches hydrate point
🔩 Material Selection
Consider low-temp carbon steel limits (-20°F for A106-B)
🔄 Multi-Stage Expansion
For ΔP > 500 psi with intermediate heating
🧊 Insulation
Prevent external condensation and ice formation

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