Methanol synthesis loop and purification (2500 t/d Grade AA, natural-gas syngas)

Low-pressure methanol synthesis loop on Cu/ZnO/Al2O3 with a boiling-water converter, recycle and purge, and two-column distillation to Grade AA methanol; make-up synthesis gas from a natural-gas reformer outside the boundary. Concept stage, assumed basis.

Calculation maturity: not assessedDesign maturity: Concept (research)Not independently reviewedMethanolReport a problem with this process
Research outputNot engineering advice and not an approved design: do not use it for construction, operation or safety decisions. What this means

The make-up synthesis gas (an assumed combined-reforming gas, stoichiometric number 2.09) is compressed to the loop pressure and joins the recycle gas at the circulator. The converter outlet is modelled as chemical equilibrium of CO hydrogenation and water-gas shift (CO2 hydrogenation is their sum) 10 K above the outlet temperature, with Peng-Robinson fugacity: a model basis, not kinetics. The crude methanol is condensed and separated at loop pressure, a purge removes the inerts, and the crude is flashed, stabilised in a topping column and refined to Grade AA in a refining column.

All values are concept estimates. The stream values and duties downstream of the make-up gas come from a converged DWSIM simulation (Peng-Robinson), cross-checked against an independent balance script; the property method is not qualified for this mixture by ChemE-as-Code yet. See DESIGN.md of the engineering files (D-014) for every assumption and gated step.

Capacity
2500 t/d Grade AA methanol (ASSUMED)
Operation
8,400 h/a
Location
generic (not chosen)
Engineering gates
Concept and feasibility (no results yet)
Maintainers
Artur Schweidtmann
Design basis and assumptions (8)
  • ASSUMED loop: boiling-water (isothermal) converter on Cu/ZnO/Al2O3, inlet 498.15 K and 8100 kPa(a), outlet 528.15 K and 7900 kPa(a) (D-003).
  • ASSUMED converter outlet at chemical equilibrium of CO hydrogenation and water-gas shift evaluated 10 K above the outlet temperature, Peng-Robinson fugacity; a model basis, not kinetics (D-005).
  • ASSUMED recycle ratio 4 (recycle/make-up, molar); the purge fraction follows from it (D-007).
  • ASSUMED HP separator 313.15 K, 7500 kPa(a); LP flash 600 kPa(a) (D-008).
  • ASSUMED topping column reflux 0.3 kmol per kmol feed, refining column reflux ratio 1.5, bottoms 100 ppm(wt) methanol (D-008).
  • ASSUMED compressor isentropic efficiency 0.75 (D-010).
  • ASSUMED no by-products (DME, higher alcohols, methyl formate, ketones): not modelled until sourced selectivities exist (D-005).
  • All flows, temperatures and duties are concept estimates from an unqualified property method (D-006); accuracy not stated.

From process/design-basis.yaml.

Engineering model

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Drawing of the process (preview)Open the engineering model

The interactive model (drawings, streams, 3D) is made for larger screens.

Snapshot of c3ab348, cheme-as-code 1.6.0.

What goes in and out

In

  • HydrogenFeedstockH2 of the make-up synthesis gas feed:SYNGAS (68 mol%, ASSUMED)
  • Carbon monoxideFeedstockCO of the make-up synthesis gas feed:SYNGAS (21.5 mol%, ASSUMED)
  • Carbon dioxideFeedstockCO2 of the make-up synthesis gas feed:SYNGAS (7.5 mol%, ASSUMED)
  • MethaneFeedstockUnconverted methane of the make-up gas feed:SYNGAS (2.5 mol%, ASSUMED), an inert of the loop, leaves with the purge

Out

  • MethanolMain productGrade AA methanol to storage, 2500 t/d design basis (2490 t/d in the DWSIM run, D-014)
  • WaterWasteRefining column bottoms water, 100 ppm(wt) methanol (ASSUMED)
  • Carbon dioxideEmissionCO2 of the flash gas and topping-column off-gas, to the fuel gas header (product:FUELGAS)

Utilities: Electricity (Make-up compressor and circulator (ASSUMED electric drives)), Steam (LP steam 450 kPa(a) to the column reboilers), Steam (MP steam 2800 kPa(a) raised in the converter (product:MPS)), Cooling water (25/35 C (ASSUMED))

Show in the process graph

Reactions

IdAs writtenReactionOther processes
MEOH_COCO + 2 H2 ⇌ CH3OHCO+2H2CH4O
MEOH_CO2CO2 + 3 H2 ⇌ CH3OH + H2OCO2+3H2CH4O+H2O
WGSCO + H2O ⇌ CO2 + H2CO+H2OCO2+H22 other processes

Each reaction's page has the conversion, heat of reaction, catalyst and sources this process states, next to those of other processes with the same reaction. All reactions

Life cycle assessment

–kg CO2-eqPreliminarypartial, 5 data gaps

Climate change per 1 kg Methanol Grade AA, gate-to-gate

No factors. No contribution is characterised, so no factor stands behind any number.

Main contributors
    Method and data
    Goal
    Preliminary gate-to-gate life cycle inventory of Grade AA methanol from the synthesis loop and purification (make-up synthesis gas at the battery limit, reforming outside), at concept stage: the foreground exchanges per kg of methanol, ready to be linked to background datasets in the next stage (DESIGN.md D-015). Flows are concept estimates; backgrounds are unmapped gaps.
    Functional unit
    1 kg Methanol Grade AA (1 kg methanol)
    Boundary
    gate-to-gate
    Allocation
    exergy
    Characterisation
    Factors kept with the process · GWP100
    Data quality
    No factors
    Result
    partial screening carbon footprint · 5 data gaps
    ScenarioClimate change (kg CO2-eq)
    baselineno total (data gaps)

    Inventory per 1 kg Methanol Grade AA (9 flows)

    FlowPhaseDirectionQuantityUnitProvenance
    Make-up synthesis gas from reformingoperationinput1.204kgassumed
    Electric poweroperationinput0.1734kWhcalculated
    LP steam 450 kPa(a)operationinput0.9259kWhcalculated
    Methanol Grade AA to storageoperationoutput1kgcalculated
    Loop purge to reformer fueloperationoutput0.09488kgcalculated
    LP flash gas and topping-column off-gas to fuel gasoperationoutput0.03458kgcalculated
    Refining column bottoms wateroperationoutput0.1266kgassumed
    MP steam raised in the converter (2800 kPa(a))operationoutput0.63kWhcalculated
    Cooling water returnoperationoutput1.551kWhcalculated

    Computed by ChemE-as-Code from lca/README.md, lca/dataset.yaml, lca/factors.yaml, lca/gaps.csv, lca/inventory.csv, lca/lca.yaml, lca/mappings.yaml, lca/results.csv, lca/results.md.

    In the open LCI database (cheme-as-code-atlas-preview-c3ab348) as Methanol Grade AA to storage Preliminary; LP flash gas and topping-column off-gas to fuel gas Preliminary; MP steam raised in the converter (2800 kPa(a)) Preliminary.

    Download it for Brightway, openLCA and other tools.

    In the LCI database: system model, datasets and KPIs against the benchmarks

    In the LCI database

    Status
    Preliminary 1 unmapped exchange. Some exchanges have no background mapping yet: they are exported unlinked and count no burden, so the inventory is incomplete.
    System model
    attributional, cut-off (methodology 1.1.0)
    Allocation
    exergy (deviation, from study) · product:FUELGAS 1.3 %, product:MEOH 94.9 %, product:MPS 3.7 %
    Allocation findings
    none
    Change report
    Not available: this build has no change report against an earlier release.
    Dataset pages
    LP flash gas and topping-column off-gas to fuel gas Preliminary · Methanol Grade AA to storage Preliminary · MP steam raised in the converter (2800 kPa(a)) Preliminary

    KPI benchmark positions: not available (no benchmarked KPI for this process's datasets).

    Maturity and review

    Design maturity Concept (claimed): An idea or first flowsheet; numbers are rough. Concept PFD with closed mass, component and element balances (cheme validate, cheme process streams). cheme maturity reaches no level yet: the make-up gas composition and the capacity are assumed (no sourced or owner-given feed). The flowsheet is simulated in DWSIM (cheme process simulate, Peng-Robinson; converged, run record process/simulation-run.json, D-014): equilibrium converter, flashes and shortcut columns; the loop agrees with the independent script (scripts/loop_balance.py) within 2.5 %, CO2 solubility in the crude and the column duties differ more. The make-up gas sized by the script for 2500 t/d gives 2490 t/d of product in the simulation (S18 flow is the simulated one, D-014). The property package is not qualified for methanol-water-syngas (predictive.property-regime fails), and the converter's MP steam level fails the utility check against its feed temperature (D-014). Not reviewed. Preliminary gate-to-gate LCI in lca/, marked preliminary with its gap in the Atlas build (DESIGN.md D-015). Main products and feeds are listed under chemistry with their chemicals registry entries (issue #251).

    Calculation maturity, from the checked evidenceNot assessed

    The process has no maturity report (cheme maturity, checks/maturity.json), so no calculation maturity is established.

    No level shownThe design maturity (Concept) is the manifest's claim, not evidence. A level appears here once the process's repository holds a current report from cheme maturity --write.

    Artifact completeness

    Which deliverables exist. They never raise a calculation maturity level: a drawing from unchecked numbers is still unchecked.

    Not reported without a maturity report.

    Independent review

    Not independently reviewed

    No independent engineering review yet. Automated checks passing is not a review.

    Set by people only. Reaching a calculation maturity level or passing automated checks is not an independent review or an approval.

    Where the evidence comes from
    Report
    processes/methanol-1/checks/maturity.json (not in the library)
    Design basis
    process/design-basis.yaml
    Method
    How ChemE-as-Code checks the levels (requirement by requirement)

    Open items

    0 open items · 0 closed

    New action itemNew engineering holdNew technical queryNew design changeAll issues

    Sources

    Engineering project
    Methanol synthesis loop and purification · cheme-as-code>=0.8
    Library version
    c3ab348 (process last changed in c3ab348)
    Drawings rendered by
    cheme 1.6.0 (pyDEXPI 2.1.0)
    Data
    Catalog record (JSON) · CC-BY-4.0
    Files
    View the files on GitHub · change history and authors

    References

    How to cite

    For the data, cite the Process Atlas paper; for the platform that builds and checks it, the ChemE-as-Code paper.

    Schweidtmann, A. M. & Weber, J. M. (2026, in preparation). Process Atlas: an open, git-native, reproducible library and life cycle inventory of chemical processes (working title).

    For this process: "Methanol synthesis loop and purification (2500 t/d Grade AA, natural-gas syngas)", ChemE-as-Code process library, version c3ab348.

    BibTeX
    @unpublished{schweidtmann_process_atlas,
  author = {Schweidtmann, Artur M. and Weber, Jana M.},
  title = {{Process Atlas: an open, git-native, reproducible library and life cycle inventory of chemical processes (working title)}},
  year = {2026},
  url = {https://atlas.cheme-as-code.org},
  note = {in preparation}
}

    Schweidtmann, A. M. (2026, in preparation). ChemE-as-Code: An Open-Source Platform for AI-Accelerated Chemical Process Engineering (working title).

    BibTeX
    @unpublished{schweidtmann_cheme_as_code,
  author = {Schweidtmann, Artur M.},
  title = {{ChemE-as-Code: An Open-Source Platform for AI-Accelerated Chemical Process Engineering (working title)}},
  year = {2026},
  url = {https://cheme-as-code.org},
  note = {in preparation}
}