neqsim-hydrate-margin-check

name	neqsim-hydrate-margin-check
calculation_basis	screening
version	0.1.0
description	Educational hydrate operating-margin screening placeholder with public assumptions. USE WHEN: a task needs a quick check of whether an operating point keeps a safe temperature margin above a hydrate equilibrium temperature and should be directed to validated NeqSim methods for real calculations.
last_verified	2026-05-31
requires	{"python_packages":[],"java_packages":[],"env":[],"network":[]}

Hydrate Margin Check

Use this skill for a quick, public check of whether a process or pipeline operating point keeps a temperature margin above a known hydrate equilibrium temperature. It is intentionally simple and should guide users toward validated NeqSim hydrate calculations for real work.

When to Use

• When a user asks whether an operating temperature stays clear of the hydrate region.
• When a validated NeqSim hydrate equilibrium temperature is already available.
• When an agent should explain that validated NeqSim methods are required for real hydrate prediction and inhibitor design.

Inputs

• operating_temperature: operating temperature in C.
• hydrate_equilibrium_temperature: hydrate equilibrium (formation) temperature in C from a validated NeqSim calculation.
• min_margin: configurable minimum acceptable margin in C (constructor, default 3.0).

Outputs

• hydrate_margin_c: operating temperature minus the hydrate equilibrium temperature in C.
• subcooling_c: subcooling into the hydrate region in C, zero when the operating point is outside the region.
• margin_warning: ok, watch, or high.
• neqsim_available: whether the optional NeqSim package is importable.
• assumptions: public assumptions and required follow-up.

Engineering Method

The placeholder method computes the hydrate margin as operating_temperature - hydrate_equilibrium_temperature. A non-positive margin means the operating point is inside the hydrate region and is flagged high. A small positive margin below min_margin is flagged watch. A larger margin is flagged ok.

This is not a thermodynamic hydrate model. The hydrate equilibrium temperature must come from a validated NeqSim hydrate calculation with a defined fluid composition, water content, inhibitor basis, and operating envelope.

Python Usage Pattern

from hydrate_margin_check import HydrateMarginModel

model = HydrateMarginModel(min_margin=3.0)
result = model.evaluate(
    operating_temperature=10.0,
    hydrate_equilibrium_temperature=8.0,
)

print(result.hydrate_margin_c)
print(result.margin_warning)
print(result.assumptions)

If the optional neqsim Python package is available, the result records that fact so an agent can recommend moving to validated NeqSim hydrate workflows. If not, the example still runs with fallback placeholder logic.

Validation Checklist

• Operating and hydrate equilibrium temperatures are finite.
• The hydrate equilibrium temperature came from a validated NeqSim calculation.
• In-region and out-of-region cases are tested.
• The minimum margin is documented as a configurable public guideline only.
• Results are not used as inhibitor dosage, design margin, or operating limit.
• Real hydrate work is redirected to validated NeqSim methods and qualified review.

Common Mistakes

Symptom	Cause	Fix
Margin looks safe but hydrates still form	Hydrate equilibrium temperature was guessed	Use a validated NeqSim hydrate equilibrium temperature
Margin warning never triggers	min_margin set too low	Use a service-appropriate operating margin and confirm with flow assurance review
Missing inhibitor effect	Inhibitor was not included in the NeqSim basis	Provide the inhibitor basis to NeqSim and recompute the hydrate temperature

Limitations

• No hydrate phase equilibrium calculation is performed in this skill.
• No salinity, methanol, MEG, kinetics, composition, or transient effects are included.
• No proprietary hydrate curves or company operating envelopes are included.
• Not suitable for flow assurance design, inhibitor dosage, or operating-limit decisions.

Related NeqSim Functionality

This educational screening corresponds to validated, rigorous functionality in the NeqSim Java library that a qualified engineer should use for design-grade work:

• neqsim.thermo.system.SystemSrkCPAstatoil — CPA equation of state for water-bearing natural gas.
• neqsim.thermodynamicoperations.ThermodynamicOperations#hydrateFormationTemperature() — rigorous hydrate equilibrium temperature and margin to operating conditions.

In Python the same classes are reachable through the neqsim package (for example from neqsim import jneqsim).

References

• NeqSim repository: https://github.com/equinor/neqsim
• NeqSim Skills Guide: https://github.com/equinor/neqsim/blob/master/docs/integration/skills_guide.md
• Sloan and Koh, Clathrate Hydrates of Natural Gases, for public hydrate background.