Steam cracking Process Flowsheets & Simulations
Explore 2 validated, solved Steam cracking simulation flowsheets in MaximaLabs — real components: ethane, ethylene, h2, n_heptane, methane, propylene. Open any one directly in your browser.
Solved via: PENG-ROBINSON.
Ethane steam cracker
A simplified thermal-cracking train: an equilibrium reactor converts ethane to ethylene + H2 at furnace conditions (1100 K), then a quench, compression, and a cold flash strip the H2 tail gas before a C2 splitter separates ethylene product from unconverted ethane. An equilibrium reactor is used here rather than the kinetic reactor because the latter's concentration term always uses a liquid-phase density (a real gap for a vapor-phase reaction at 1100 K) -- noted, not fixed, out of scope for this example. The C2 splitter needs many stages and high reflux since ethylene/ethane relative volatility is modest. From the ChemSep casebook (ethane cracker).
10 unit ops • PENG-ROBINSON
21 0
View & openNaphtha steam cracker: furnace, quench, compression, cryo train
The full ethylene-plant process shape (steam-methane-cracking's headline technology, e.g. Linde's steam cracking line): a fired-heater convection preheat, a three-reactor lumped pyrolysis furnace, a transfer-line-exchanger quench, a primary fractionator pulling off pyrolysis gasoline, two-stage compression with interstage knockouts, selective acetylene hydrogenation, and a cryogenic cold train (cold-flash light-gas rejection, deethanizer, C2 splitter, depropanizer) delivering four real products -- ethylene, propylene, a butadiene-rich C4 cut, and a pygas/heavy-ends byproduct -- plus an H2/CH4-rich tail gas and two knockout condensate streams. Honesty notes: (1) naphtha is modeled as a single n-heptane surrogate (no fitted radical-chain kinetics exist in this codebase for real naphtha pyrolysis, so the furnace is three chained fixed-conversion reactors on real, exactly mass-balanced cracking/dehydrogenation stoichiometry -- C7H16 -> C2H4+C2H6+C3H6, C7H16 -> CH4+C2H4+C4H6+H2, and C2H4 -> C2H2+H2 for a trace acetylene impurity -- tuned to a representative, not literature-fitted, product distribution, the same 'illustrative, not fitted' posture already disclosed for saf-hefa-renewable-jet's hydrocracking lump). (2) The demethanizer is a single cold flash stage, not a rigorous multi-tray column: H2 is permanently supercritical at any realistic column pressure (Pc~13 atm vs. the ~20+ atm this train runs at), which was found during this build to corrupt the MESH solver's initial temperature-profile guess (fixed in unitops/distillation.py -- see its CLAUDE.md entry -- but even after that fix a genuine ~15 mol% H2 feed to a sharp-cut demethanizer is a hard column this solver doesn't converge on cleanly); a single flash stage rejects H2/CH4 in bulk instead, consistent with the 'cold-box front-end flash' some real designs use, but with materially worse light-key rejection than a real 20+ tray demethanizer. That carries through honestly to the ethylene product: it converges at ~77 mol% ethylene (the balance methane and H2), not polymer-grade purity -- the real number the solver computes, not an assumed spec. Propylene fares much better (~96%) since it isn't competing with as light a contaminant. (3) No BTX/aromatics extraction -- the pygas cut is reported as a single lumped heavy stream, matching saf-hefa's precedent of not resolving every real product cut.
30 unit ops • PENG-ROBINSON
36 2
View & open