Sour Gas Amine Treating

Sour Gas Amine Treating (Screening)

Overview

Lightweight mass-balance helpers for aqueous amine sweetening:

• Lean/rich loading in mol acid gas per mol amine from measured flows.
• Required lean amine mass flow for a target rich loading.
• Warning if rich loading exceeds widely cited envelopes (corrosion risk).

This skill is for screening, troubleshooting, and operator-discussion support. It does NOT model the absorber rate-based kinetics, the regenerator stripping behaviour, or the corrosion-loading interaction.

Prerequisites

1. uv available.
2. On first use, the script writes LICENSE_NOTIFICATION.txt.

When to Use

• Estimating required amine circulation for a known acid gas load.
• Checking whether observed rich loading is in the safe envelope.
• Cross-checking a vendor sizing for a sweetening unit.

Don't use for

• Rate-based simulation of the absorber or regenerator (use ProMax,

ProTreat, Aspen Amines).

• Predicting foaming, corrosion, or heat-stable salt formation.
• Selecting the amine itself (DEA vs MDEA vs blends): consult vendor

recommendations and operating history.

Utility Scripts

• uv run scripts/amine.py loading --acid-gas-mol-s 0.5 --amine-mol-s 5 --output /tmp/loading.json
• uv run scripts/amine.py circulation --acid-gas-mol-s 0.5 --rich 0.40 --lean 0.05 --amine DEA --wt-fraction 0.30 --output /tmp/circ.json

Procedure

1. From the inlet sour-gas composition and flow, compute the acid-gas

molar load (H2S + CO2). Use vle-flash-calculations if needed.

1. Decide a target rich loading (typical envelopes: DEA 0.35-0.45 mol/mol,

MDEA 0.40-0.55 mol/mol). Cross-check against vendor envelope.

1. Decide a lean loading (regenerator performance dependent; typical

0.01-0.10 mol/mol).

1. Run circulation; the script returns required amine molar and mass

flow, and the solution mass flow at the chosen wt%.

1. Verify the result against the existing pump capacity and lean amine

exchanger duty.

Pitfalls

• Treating "loading" as wt%; loading is mol acid gas per mol amine. They

are very different quantities.

• Using a single rich loading for H2S+CO2 mixed streams without thinking

about the relative absorption rates (DEA absorbs both; MDEA preferentially absorbs H2S over CO2).

• Forgetting that the rich loading envelope depends on amine concentration:

higher wt% generally lower allowable loading due to corrosion.

• Sizing circulation only for the average case and ignoring upsets (e.g.

feed sulfur swings).

• Assuming the lean amine is at the stripper outlet condition; lean amine

cooler and pump can change concentration (e.g. cold lean amine may contain dissolved gases that re-vapourise in the absorber).

• Using mass balance loading without checking the regenerator's actual

performance (it may not strip to the assumed lean loading).

• Ignoring heat-stable salt accumulation in long-run operation.

Fallback Strategies

• For rigorous design, surface to the user that a rate-based simulator is

required.

• If acid gas load is unknown, use vle-flash-calculations to estimate

H2S/CO2 partial pressures and flow.

Verification

• Run the listed script with representative inputs and an --output file when a deterministic calculation is available.
• Confirm the JSON result contains ok: true, expected units, and no unhandled warnings.
• Check result magnitudes against the stated assumptions, references, and a hand calculation or known operating range before reporting them.

References

• references/loading_envelopes.md — published rich loading envelopes and

caveats.

• GPSA Engineering Data Book (Section 21 — Hydrocarbon Treating).
• Kohl & Nielsen, Gas Purification (5th ed).

Anti-Patterns

• Reporting "amine circulation 100 GPM" without stating lean and rich

loadings.

• Picking the rich loading from the top of the envelope without an

operating margin.

• Using this skill output to specify a tower without rigorous review.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: jskherman
• Source: jskherman/engg-skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.