neqsim-water-dewpoint-dehydration-screening

name	neqsim-water-dewpoint-dehydration-screening
calculation_basis	screening
version	0.1.0
description	Educational gas water-content and dehydration screening using the public GPSA Bukacek saturated-water-content correlation. USE WHEN: a task needs a public, screening-level estimate of saturated water content in natural gas and a check against a sales-gas water spec before detailed dehydration design.
last_verified	2026-06-18
requires	{"python_packages":[],"java_packages":[],"env":[],"network":[]}

Water Dewpoint Dehydration Screening

Use this skill for public, educational gas water-content screening. It estimates the saturated water content of natural gas using the open GPSA Bukacek correlation and compares it to a sales-gas water specification so an agent can flag whether dehydration is likely required before detailed design.

When to Use

• When a user asks whether a gas stream needs dehydration to meet a water spec.
• When an agent needs a quick saturated-water-content estimate to scope a dehydration study.
• When examples must run without confidential dehydration designs, glycol data, or company gas specs.

Inputs

• pressure: gas pressure in bar absolute.
• temperature: gas temperature in kelvin.
• water_spec: sales-gas water-content specification in lb/MMscf, default 7.0 (common pipeline spec).

Outputs

• saturated_water_content_lb_mmscf: saturated water content from the Bukacek correlation.
• water_spec_lb_mmscf: the supplied water specification.
• spec_ratio: ratio of saturated water content to the spec.
• dehydration_required: whether the saturated content exceeds the spec.
• dehydration_warning: ok, watch, or dehydration-required.
• assumptions: public assumptions used by the placeholder model.

Engineering Method

The Python class WaterDewpointModel uses the open GPSA Bukacek correlation only:

• the saturated water content uses W = A / P + B, where A and B are public temperature-dependent terms and P is in psia.
• the spec ratio compares the saturated content to the supplied water spec.
• the warning is a simple rule-based label aligned with sales-gas dehydration intent.

This is educational and screening-only logic. The Bukacek correlation is for sweet natural gas in equilibrium with liquid water and is most accurate above 32 F. It does not include acid-gas corrections, salinity, hydrate suppression, or glycol contactor performance. It is not a replacement for validated water-content and dehydration design (for example GPSA and rigorous thermodynamics) and a qualified process review.

Python Usage Pattern

from water_dewpoint_dehydration_screening import WaterDewpointModel

model = WaterDewpointModel()
result = model.evaluate(
    pressure=70.0,
    temperature=305.15,
)

print(result.dehydration_warning)
print(result.saturated_water_content_lb_mmscf)
print(result.dehydration_required)

Related NeqSim Functionality

For validated water-content and dehydration calculations, redirect to existing NeqSim functionality:

• neqsim.thermo.system.SystemSrkCPAstatoil (CPA equation of state) — rigorous water content and water dew point for natural gas.
• neqsim.process.design.template.DehydrationTemplate — TEG dehydration process template.
• neqsim.process.equipment.absorber glycol contactor models — detailed dehydration performance.

This skill is a public Bukacek triage layer that decides when to invoke validated NeqSim water-content and dehydration models.

Validation Checklist

• Pressure and temperature are positive and in the stated units.
• Example inputs are public and synthetic.
• Tests cover an in-spec case, a dehydration-required case, and invalid input.
• Results are described as educational screening indicators.
• Real design is redirected to validated methods, GPSA, NeqSim CPA, and qualified review.

Common Mistakes

Symptom	Cause	Fix
Water content too low	Acid-gas content ignored	Add CO2 and H2S corrections with a validated method
Spec check wrong	Volume basis mismatch (MMscf vs MMsm3)	Keep the water spec on the same basis as the correlation
Out-of-range result	Temperature below the correlation range	Use a validated method below freezing or near hydrate conditions

Limitations

• No proprietary dehydration designs, glycol data, or company gas specs are included.
• No acid-gas, salinity, or hydrate-suppression corrections are performed.
• No glycol contactor or regeneration performance is modeled.

References

• NeqSim repository: https://github.com/equinor/neqsim
• NeqSim Skills Guide: https://github.com/equinor/neqsim/blob/master/docs/integration/skills_guide.md