Ethanol by direct hydration of ethylene (100 000 t/a anhydrous, phosphoric acid catalyst)

Vapour-phase hydration of polymer-grade ethylene over phosphoric acid on silica with a large gas recycle, water scrubbing, light-ends and concentrating distillation and molecular-sieve dehydration to anhydrous ethanol. Concept stage, assumed basis, gate-to-gate LCI with unmapped backgrounds.

Calculation maturity: not assessedDesign maturity: Concept (research)Not independently reviewedOxygenatesReport 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

Ethylene from a steam cracker outside the boundary joins the recycle gas, takes up process water (0.35 mol per mol ethylene) and is heated against the reactor effluent and with HP steam to 240 C. About 5 % of the ethylene is hydrated per pass in an adiabatic bed at about 7 MPa (patent literature: US 4003952, US 5349096). The effluent is cooled, the crude ethanol separated and the gas scrubbed with water and recycled; a small purge controls the inerts. The crude (about 12 mol% ethanol) is flashed, freed of ether and butenes in a light-ends column, concentrated to 93 wt% and dehydrated on molecular sieves. Fermentation, the dominant route for ethanol by volume, is not designed here.

All values are concept estimates: the reactor outlet is calculated by cheme from a sourced conversion with assumed selectivities, the separators are specified splits and the duties come from an independent script (see DESIGN.md of the engineering files).

Capacity
100 000 t/a anhydrous ethanol (ASSUMED), 12 500 kg/h
Operation
8,000 h/a
Location
generic (not chosen)
Engineering gates
Concept and feasibility (no results yet)
Maintainers
Artur Schweidtmann
Design basis and assumptions (6)
  • Reactor R-101: adiabatic fixed bed of phosphoric acid on silica, inlet 513.15 K and 7050 kPa(a), water/ethylene 0.35 mol/mol (US 5349096 ranges; D-003).
  • Conversion of ethylene 5 % per pass (US 4003952, prior-art description: 4-5 %); selectivity 0.97 ethanol, 0.01 diethyl ether, 0.005 butenes per kmol ethylene converted, ASSUMED (D-004).
  • Separators, scrubber and columns: specified component splits, ASSUMED (D-005); duties from scripts/balance.py, ideal gas plus latent heats (D-006).
  • Loop purge 0.1 % of the scrubbed gas, water-loop blowdown 10 % of the C-202 bottoms, ASSUMED (D-005).
  • Phosphoric acid carried out of the reactor is made up to the catalyst and neutralised with caustic soda in the effluent: both small, not in the stream table, counted in the LCI as ASSUMED consumables (D-007).
  • All flows, temperatures and duties are concept estimates from an unqualified 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

  • EthyleneFeedstockfeed:ETHYLENE: polymer-grade ethylene from a steam cracker (e.g. ethylene-1), 0.646 kg/kg ethanol
  • WaterFeedstockDemineralised make-up water: reaction water and the water-loop blowdown

Out

  • EthanolMain productAnhydrous ethanol to storage
  • WastewaterWasteWater-loop blowdown, ~100 ppm(wt) ethanol and the neutralised acid
  • Waste gas to flareWasteLoop purge and light-ends off-gas (ethylene, ethane, butenes, diethyl ether, ethanol) burned in the site fuel-gas system (a waste with energy recovery outside the boundary, D-013); the registry has no fuel-gas entry, flare-gas is the nearest

Utilities: Electricity (Compressors, process water pump, sieve vacuum pump (ASSUMED electric drives)), Steam (HP steam 4200 kPa(a) to the reactor feed superheater), Steam (LP steam 450 kPa(a) to the column reboilers), Cooling water (25/35 C (ASSUMED))

Show in the process graph

Reactions

IdAs writtenReactionOther processes
ETHER2 C2H4 + H2O ⇌ (C2H5)2O2C2H4+H2OC4H10O
HYDC2H4 + H2O ⇌ C2H5OHC2H4+H2OC2H6O
OLIGO2 C2H4 → C4H82C2H4C4H8

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, 16 data gaps

Climate change per 1 kg Anhydrous ethanol, cradle-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 anhydrous ethanol (99.8 wt%) from vapour-phase direct hydration of ethylene at concept stage, per kg of product, with every background still open: only the foreground exchanges of the balanced flowsheet are quantified (ethylene, water, power, HP and LP steam, cooling water, off-gas, wastewater, consumables); the backgrounds, ethylene above all, are gaps to be linked later. Not a carbon footprint (D-013).
    Functional unit
    1 kg Anhydrous ethanol (1 kg ethanol)
    Boundary
    cradle-to-gate
    Allocation
    none
    Characterisation
    Factors kept with the process · GWP100
    Data quality
    No factors
    Result
    partial screening carbon footprint · 16 data gaps
    ScenarioClimate change (kg CO2-eq)
    baselineno total (data gaps)

    Inventory per 1 kg Anhydrous ethanol (17 flows)

    FlowPhaseDirectionQuantityUnitProvenance
    Polymer-grade ethylene from a steam crackeroperationinput0.646kgassumed
    Demineralised make-up wateroperationinput0.6777kgassumed
    Electric poweroperationinput0.05511kWhassumed
    HP steam 4200 kPa(a)operationinput0.3714kWhassumed
    LP steam 450 kPa(a)operationinput1.43kWhassumed
    Anhydrous ethanol to storageoperationoutput1kgassumed
    Loop purge and light-ends off-gas to the fuel-gas headeroperationoutput0.05167kgassumed
    Water-loop blowdown to wastewater treatmentoperationoutput0.2721kgcalculated
    Cooling water returnoperationoutput2.207kWhassumed
    Phosphoric acid make-up to the catalyst (as 100 % H3PO4)operationinput0.0009998kgassumed
    Disposal: Phosphoric acid make-up to the catalyst (as 100 % H3PO4) (neutralised to sodium phosphate, leaves with the blowdown to biological wastewater treatment)operationoutput0.0009998kgassumed
    Caustic soda for the acid neutralisation (as 100 % NaOH)operationinput0.0008199kgassumed
    Disposal: Caustic soda for the acid neutralisation (as 100 % NaOH) (as sodium phosphate in the blowdown to biological wastewater treatment)operationoutput0.0008199kgassumed
    Hydration catalyst (H3PO4 on silica), R-101 chargeoperationinput0.00015kgassumed
    Disposal: Hydration catalyst (H3PO4 on silica), R-101 charge (landfill of the spent acid-impregnated silica after neutralisation)operationoutput0.00015kgassumed
    Molecular sieve 3A (V-301 beds)operationinput0.00005999kgassumed
    Disposal: Molecular sieve 3A (V-301 beds) (landfill of spent zeolite (inert))operationoutput0.00005999kgassumed

    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 Anhydrous ethanol to storage 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 6 unmapped exchanges. 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
    none (single-output, from study) · product:ETOH 100 %
    Allocation findings
    none
    Change report
    Not available: this build has no change report against an earlier release.
    Dataset pages
    Anhydrous ethanol to storage 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 in every block and step (cheme validate, cheme process streams). The reactor outlet is calculated by cheme from a sourced per-pass conversion (US 4003952) with assumed selectivities, and its adiabatic energy balance closes on the ideal-gas data; separators, columns, the molecular sieve and all other duties are specified values from an independent script (scripts/balance.py) whose method core cannot qualify for ethylene/water/ethanol. Not reviewed. 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/ethanol-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
    Ethanol (ethylene direct hydration) · 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: "Ethanol by direct hydration of ethylene (100 000 t/a anhydrous, phosphoric acid catalyst)", 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}
}