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Gas Dewatering Calculator

McKetta-Wehe · GPSA · Pipeline Dehydration Specs

Gas Dewatering Requirements Calculator
Evaluates natural gas dewatering needs for pipeline transport. Calculates water content at operating conditions using McKetta-Wehe correlation, determines required water removal rate, and recommends the optimal dehydration method based on dewpoint depression.

Gas Flow & Conditions

MMSCFD
psig
°F
air=1.0

Water Content & Dewpoint Spec

lb/MMSCF
°F
Dewpoint Specs

Pipeline tariffs typically require <7 lb/MMSCF or a water dewpoint of 32°F. Cryogenic plants need <1 ppmv (<0.1 lb/MMSCF). Arctic pipelines may require -40°F dewpoint.

Acid Gas Content (Optional)

mol%
mol%
/* McKetta-Wehe Water Content */
W = W1000(T) × CP × CSG × CCO2 × CH2S
// W1000 = GPSA Fig 20-3 at 1000 psia
// CP = pressure correction factor

About This Calculator

Evaluates gas dewatering requirements using McKetta-Wehe water content correlation and GPSA dehydration method selection guidelines.

Calculations Include:

  • Inlet Water Content: McKetta-Wehe chart correlation with acid gas correction
  • Outlet Water Content: From required dewpoint specification
  • Water Removal Rate: Daily and hourly removal requirements
  • Method Recommendation: TEG, molecular sieve, refrigeration, or CaCl2
  • TEG Circulation: Estimated glycol rate if TEG is recommended

⚡ Quick Reference — Dewatering Methods

TEG Glycol: 30-80°F depression
Mol. Sieve: >100°F depression
Refrigeration: 20-60°F depression
CaCl2: 15-30°F depression
Pipeline Spec: <7 lb/MMSCF
Cryogenic: <0.1 lb/MMSCF

Dehydration Method Comparison

Method Dewpoint Cost
TEG Glycol -40 to 32°F Low-Med
DEG Glycol 0 to 40°F Low
Mol. Sieve -150 to -60°F High
Refrigeration 15 to 40°F Med-High
CaCl2 30 to 50°F Very Low
Water Content vs. Dewpoint

Water content in natural gas is determined by temperature and pressure. Higher temperatures increase water carrying capacity while higher pressures reduce it. The McKetta-Wehe chart is the industry-standard method for sweet gas; acid gas correction factors are applied for CO2 and H2S content per GPSA.

Hydrate Prevention

Gas dewatering is the primary method for preventing hydrate formation. Reducing water content below the saturation point at the coldest expected pipeline temperature eliminates free water and prevents hydrate nucleation. For gathering systems, target a dewpoint 15-20°F below the minimum ground temperature.

References

  • GPSA Engineering Data Book, Sections 20-21
  • McKetta-Wehe Water Content Chart
  • Campbell Gas Conditioning and Processing
  • API 14E — Pipeline Sizing

Frequently Asked Questions

What does the gas dewatering calculator do?

It determines water content, removal rates, and recommends dehydration methods for meeting pipeline specifications using the McKetta-Wehe correlation.

What correlation does this dewatering calculator use?

The calculator uses the McKetta-Wehe correlation to determine water content in natural gas at given temperature and pressure conditions.

Is this gas dewatering calculator free?

Yes, this is a free gas dewatering calculator with instant results for pipeline dehydration requirements.

What is the McKetta-Wehe correlation used for in gas dewatering?

The McKetta-Wehe correlation calculates the water content of natural gas at specified temperature and pressure conditions. It includes corrections for acid gas content (CO2 and H2S) and gas specific gravity to determine inlet water loading in lb/MMSCF.

What water dewpoint specification is required for pipeline gas?

Pipeline tariffs typically require less than 7 lb/MMSCF water content or a water dewpoint of 32°F. Cryogenic plant feeds need less than 0.1 lb/MMSCF (less than 1 ppmv), and Arctic pipelines may require -40°F dewpoint.

How does the calculator recommend a dehydration method?

The calculator compares the required dewpoint depression against each method's capability: TEG glycol handles 30-80°F depression, molecular sieve exceeds 100°F, refrigeration achieves 20-60°F, and CaCl2 provides 15-30°F depression. It selects the most cost-effective option for the required outlet specification.

What effect do acid gases have on natural gas water content?

CO2 and H2S increase the water content of natural gas compared to sweet gas at the same conditions. The McKetta-Wehe correlation applies correction factors for acid gas content to accurately predict water loading for sour gas streams.