Neqsim Acid Gas Treating

Gotchas

• SimpleAmineAbsorber is efficiency-based bookkeeping. The configured amine type, weight percent, loadings, and circulation/packing calculations do not turn it into a reactive equilibrium model.
• The simple absorber adds captured CO2/H2S to the lean-solvent clone only if that component already exists in the solvent system. Include the acid-gas components (trace if needed) in the lean solvent or the absorber-side material balance will not include those captured moles. The absorber now logs a warning when removed CO2/H2S has no matching component in the lean solvent.
• SimpleAmineRegenerator reports CO2 loading and duty; it removes H2S separately. Do not read its CO2 loading as total acid-gas loading. Duty getters remain zero when no CO2 is stripped or no positive molar flow is present.
• For a real lean/rich recycle, use a pressure let-down, cooler, pump, and Recycle/converged flowsheet. Check recycle convergence and make a component-wise balance; a sequential example is not a closed-loop process model.
• Flash exceptions in the simple amine equipment are logged and caught. A populated output stream can therefore exist after a failed flash; check phase/composition results and finite properties.
• RateBasedAbsorberTest allows KGa, KLa, wetted area, and HTU to be zero. Treat zero, NaN, or non-finite transfer metrics as an unusable calculation, not a successful separation.
• MembraneSeparator defaults component permeate fractions to zero. Its permeability option uses permeability * area * feed partial pressure, capped at available component moles; it is a simplified split calculation, not a pressure-driven multi-stage membrane design.
• PressureSwingAdsorptionBed recovery target is enforced by venting excess product hydrogen to tail gas; it is not the result of simulating industrial cycle sequencing. Use PSACascade or AdsorptionCycleController for the corresponding simplified cycle abstractions.
• Use K and bara in thermo constructors. SimpleAmineRegenerator.setReboilerTemperatureC(double) takes Celsius; column geometry uses m; scavenger contact time uses seconds; PSA tail flows are mol/s. Use explicit stream flow units.
• Set the mixing rule before a flash. The tested SystemSrkEos workflows use "classic"; the Kent-Eisenberg test uses numeric 4. The tested reactive Desmukh-Mather workflow order is chemicalReactionInit(), createDatabase(true), then setMixingRule("classic"), TP flash, and initProperties() before transport-property reads. Numeric CPA rule 10 belongs to CPA model workflows; no amine validation test here uses SystemElectrolyteCPAstatoil.
• AdsorptionBed.validateSetup() reports required geometry/material errors with remediation, e.g. “Bed diameter must be positive” / “Set bed diameter: setBedDiameter(value)” and “Adsorbent material not specified” / “Set adsorbent material: setAdsorbentMaterial(name)”. Call it and fix errors before running the bed.
• SimpleAbsorber exposes the legacy spelling setAproachToEquilibrium(double); the amine-specific class instead exposes setApproachToEquilibrium(double).

Validation / benchmarks

• Require sweet-gas acid-gas component fractions/rates below their sour-feed values and verify the captured material appears in rich solvent or the selected removal stream.
• For a regenerator, require rich loading at least lean loading, positive CO2 in acid-gas overhead, and positive finite duty when CO2 is stripped. Use the duty model as an estimate, not a vendor energy guarantee.
• Amine loading is mol acid gas/mol amine. Rich loading must exceed lean loading; numeric targets vary with solvent, circulation, pressure, temperature, and feed composition. Compare against measured PVT/plant data or a documented design basis. Reference: Kohl & Nielsen, Gas Purification.
• The PSA unit documents a typical industrial H2 recovery target range of 0.75-0.90 depending on equalisation steps. Its test uses a 0.85 target, checks purity above 0.85, recovery in 0.80-0.85, and total feed = product + tail gas within 1%. These are model regression checks, not proof of a specific vendor skid rating.
• For a membrane, verify total molar balance and the intended permeate/retentate enrichment; a set fraction is the assumed selectivity, not evidence of measured membrane performance.
• AbsorptionColumnTest checks convergence, component balance, and effect of reduced Murphree efficiency. RateBasedAbsorberTest only requires non-negative transfer metrics; add positive, finite-value checks and independent validation for engineering use.
• References for process context: GPSA Engineering Data Book, Gas Purification (Kohl & Nielsen), and the relevant solvent, packing, membrane, or adsorbent vendor data. No clause-level compliance claim is made here.

Related skills

• neqsim-process-modeling — connect treating equipment, utilities, recycle, and downstream units.
• neqsim-teg-dehydration-modeling — validated TEG dehydration flowsheet and regeneration loop.
• neqsim-hydrogen-production — PSA purification and hydrogen-chain context.
• neqsim-reaction-engineering — reaction and equilibrium-model selection.
• neqsim-api-patterns — fluid setup, mixing rules, units, and property initialization.
• neqsim-input-validation — component, phase, and operating-condition screening.
• neqsim-troubleshooting — flash, column, and recycle diagnosis.
• neqsim-standards-lookup — standards identification and clause-to-method traceability.
• neqsim-professional-reporting — report assumptions, evidence, and limitations.
• neqsim-sulfur-recovery — route recovered Claus acid gas to sulfur recovery and tail-gas handling.