{
  "authors": [],
  "basis": {
    "capacity": "100 kt/a benzene (ASSUMED)",
    "location": "generic (not chosen)",
    "operating_hours_per_year": 8000
  },
  "benchmarks": [],
  "chemistry": {
    "inputs": [
      {
        "chemical": "toluene",
        "grade": null,
        "note": "feed:TOLF: fresh toluene, 1.23 kg/kg benzene",
        "role": "feedstock"
      },
      {
        "chemical": "hydrogen",
        "grade": null,
        "inventory_key": "feed:H2MU",
        "note": "Make-up hydrogen of PSA grade, 99.9 mol% (D-020)",
        "role": "feedstock"
      },
      {
        "chemical": "methane",
        "grade": null,
        "inventory_key": "feed:H2MU",
        "note": "0.1 mol% methane taken as the rest of the make-up hydrogen (ASSUMED), leaves with the PSA tail gas",
        "role": "feedstock"
      }
    ],
    "outputs": [
      {
        "chemical": "benzene",
        "grade": null,
        "inventory_key": "product:BENZENE",
        "note": "Benzene to storage",
        "role": "main-product"
      },
      {
        "chemical": "biphenyl",
        "grade": null,
        "inventory_key": "product:DIPHENYL",
        "note": "Biphenyl (diphenyl) by-product",
        "role": "co-product"
      },
      {
        "chemical": "hydrogen",
        "grade": null,
        "inventory_key": "product:FUELGAS",
        "note": "PSA tail gas and stabiliser off-gas (about 14 mol% H2, 84 % CH4, D-024) to the fuel gas header",
        "role": "co-product"
      },
      {
        "chemical": "methane",
        "grade": null,
        "inventory_key": "product:FUELGAS",
        "note": "Methane formed by the reaction and with the make-up, in the fuel gas",
        "role": "co-product"
      }
    ],
    "utilities": [
      {
        "chemical": "electricity",
        "grade": null,
        "inventory_key": "feed:POWER",
        "note": "Recycle compressor and toluene pump (ASSUMED electric drives)",
        "role": "utility"
      },
      {
        "chemical": "steam",
        "grade": null,
        "inventory_key": "feed:MPS",
        "note": "MP steam 1500 kPa(a), stabiliser reboiler",
        "role": "utility"
      },
      {
        "chemical": "steam",
        "grade": null,
        "inventory_key": "feed:LPS",
        "note": "LP steam 450 kPa(a), benzene column reboiler",
        "role": "utility"
      },
      {
        "chemical": "steam",
        "grade": null,
        "inventory_key": "feed:HPS",
        "note": "HP steam 4200 kPa(a), toluene column reboiler",
        "role": "utility"
      },
      {
        "chemical": "cooling-water",
        "grade": null,
        "inventory_key": "product:CW",
        "note": "25/35 C (ASSUMED)",
        "role": "utility"
      }
    ]
  },
  "description": "Fresh and recycled toluene are pumped, mixed with PSA-grade make-up hydrogen (99.9 mol%) and\nrecycle gas at a hydrogen-to-aromatics ratio of 5, preheated against the reactor effluent and\nin a fired heater to 895 K, and react adiabatically at about 3.4 MPa (outlet 936 K). The\nreactor model takes 75 % toluene conversion per pass, the per-pass conversion of a published\nthermal HDA process (US 3,291,849), and the biphenyl reaction to equilibrium at the outlet. The\neffluent is quenched with separator liquid, cooled and separated at 313 K; a purge of the\ncompressed recycle gas (40 mol% H2) removes the methane. A pressure swing adsorption unit\nrecovers 75 % of the purge's hydrogen at 99.9 mol% into the recycle compressor suction, and\nits tail gas is compressed into the fuel gas header. The liquid is\nstabilised, benzene (99.9 mol%) is taken overhead in the benzene column and cooled to 313 K,\nand the vacuum toluene column returns toluene to the reactor and leaves biphenyl as bottoms.\n\nAll values are concept estimates. The separator, column and duty values come from a DWSIM\nsimulation of the whole plant (Peng-Robinson). ChemE-as-Code has not yet qualified that\nproperty package for this mixture, so the simulation is a cross-check of an independent\nbalance script, not validated data; see DESIGN.md of the engineering files (D-014, D-020 to D-024) for every\nassumption and gated step. Designed independently: no flowsheet data of the IDAES HDA examples are used.\n",
  "design_basis": {
    "assumptions": [
      "ASSUMED thermal (non-catalytic) HDA: adiabatic reactor, inlet 895.15 K and 3450 kPa(a), outlet temperature from the energy balance (D-004).",
      "Toluene conversion per pass 0.75, the per-pass conversion of a published thermal HDA reactor (US 3,291,849, D-021); biphenyl at chemical equilibrium at the reactor outlet (formation data of process/materials.yaml), which gives a benzene selectivity of 0.973: a conversion and equilibrium model, not kinetics. The equilibrium bounds the biphenyl make only, not the selectivity loss: heavier polyaromatics and hydrocracking are excluded (the next assumption), so 0.973 is optimistic. US 3,607,960 Example 1 reports 94.5 % for its primary reactors at 85 % conversion per pass, a higher conversion than R-101's (process/reaction-evidence.yaml O2); the TEA carries it as a scenario (D-021). The 0.75 is the patent reactor's value adopted as R-101's design value; R-101's volume and residence time are not designed to it. The recalled Douglas (1988) correlation of D-005 is no longer used (I-06).",
      "ASSUMED loop specifications: H2/aromatics 5 mol/mol at the reactor inlet, purge gas 40 mol% H2 (D-007).",
      "ASSUMED quench of the reactor effluent to 893.15 K with separator liquid (quench pump P-102); separator 313.15 K, 3250 kPa(a) (D-004, D-022).",
      "Benzene product cooled to 313.15 K in the product cooler E-207 (D-022).",
      "ASSUMED columns: stabiliser 800 kPa(a) with partial condenser at 313.15 K, L/D 1; benzene column 150/170 kPa(a), 99.5 % benzene recovery; toluene column 30/45 kPa(a) (vacuum), 2 mol% toluene in the biphenyl; reflux 1.3 x Underwood minimum, at least 0.5 (D-008).",
      "ASSUMED compressor isentropic efficiency 0.75, pump efficiency 0.65 (D-010).",
      "ASSUMED no other side reactions (heavier polyaromatics, hydrocracking to light paraffins, methylbiphenyls, coke): not modelled, because no source read in full gives their split; US 3,607,960 reports 'polyphenyls (primarily diphenyl) and higher boiling polymers' in the effluent of a primary thermal zone (D-005, D-021).",
      "All flows, temperatures and duties are concept estimates from an unqualified property method (Peng-Robinson in thermo, D-006); accuracy not stated."
    ],
    "source": "process/design-basis.yaml"
  },
  "engineering": {
    "description": "",
    "name": "Toluene hydrodealkylation to benzene",
    "requires": "cheme-as-code>=0.8",
    "stage": "concept",
    "stages": [
      {
        "id": "concept",
        "title": "Concept and feasibility"
      },
      {
        "id": "basic",
        "title": "Basic engineering"
      },
      {
        "id": "detail",
        "title": "Detail engineering"
      }
    ],
    "tool": "plantcode"
  },
  "facets": {
    "feedstock_basis": [
      "fossil"
    ],
    "product_classes": [
      "chemicals"
    ],
    "region": "generic",
    "unit_operations": [
      "reaction",
      "heat-exchange",
      "compression",
      "flash",
      "distillation",
      "adsorption"
    ]
  },
  "families": [
    "aromatics"
  ],
  "gap_count": 0,
  "gates": {
    "checks": [
      {
        "id": "design-basis",
        "stage": "concept",
        "status": "pass",
        "title": "Design basis exists"
      },
      {
        "id": "concept-lists",
        "stage": "concept",
        "status": "pass",
        "title": "Design decisions and the equipment, line and instrument lists exist"
      },
      {
        "id": "process-concept",
        "stage": "concept",
        "status": "pass",
        "title": "Materials and flowsheet exist (the BFD is generated by cheme process build)"
      },
      {
        "id": "process-balances",
        "stage": "concept",
        "status": "pass",
        "title": "Every block balance is evaluable and clean, the BFD current"
      },
      {
        "id": "process-links-concept",
        "stage": "concept",
        "status": "pass",
        "title": "Process links resolve (reported only)"
      },
      {
        "id": "assumptions-marked",
        "stage": "concept",
        "status": "pass",
        "title": "Assumed values are marked ASSUMED in the design basis"
      },
      {
        "id": "layout-plot-plan",
        "stage": "concept",
        "status": "pass",
        "title": "Plot plan - site, areas, roads, racks, every item placed, separations declared"
      },
      {
        "id": "issues-concept",
        "stage": "concept",
        "status": "n/a",
        "title": "No open item to close before the concept gate"
      }
    ],
    "counts": {
      "n/a": 1,
      "pass": 7
    },
    "total": 8
  },
  "id": "hda-1",
  "issues": {
    "closed_count": 0,
    "list_url": "https://github.com/ChemE-as-Code/process-library/issues?q=is%3Aissue%20label%3A%22process%3Ahda-1%22",
    "new": {
      "action": "https://github.com/ChemE-as-Code/process-library/issues/new?template=1-action-item.yml&labels=process%3Ahda-1&process=hda-1",
      "change": "https://github.com/ChemE-as-Code/process-library/issues/new?template=4-design-change.yml&labels=process%3Ahda-1&process=hda-1",
      "hold": "https://github.com/ChemE-as-Code/process-library/issues/new?template=2-engineering-hold.yml&labels=process%3Ahda-1&process=hda-1",
      "process": "https://github.com/ChemE-as-Code/process-library/issues/new?template=6-process-development.yml&labels=process%3Ahda-1&process=hda-1",
      "tq": "https://github.com/ChemE-as-Code/process-library/issues/new?template=3-technical-query.yml&labels=process%3Ahda-1&process=hda-1",
      "tracker": "https://github.com/ChemE-as-Code/process-library/issues/new?template=7-process-tracker.yml&labels=process%3Ahda-1&process=hda-1"
    },
    "open": [],
    "open_by_gate": {},
    "open_count": 0,
    "private": false,
    "repository": "ChemE-as-Code/process-library"
  },
  "keywords": [
    "benzene",
    "toluene",
    "hydrodealkylation",
    "HDA",
    "hydrogen recycle",
    "purge",
    "PSA",
    "biphenyl",
    "diphenyl",
    "distillation",
    "aromatics"
  ],
  "lca": null,
  "lci_gaps": [],
  "maintainers": [
    {
      "name": "Artur Schweidtmann"
    }
  ],
  "maturity": "concept",
  "preliminary": false,
  "provenance": {
    "library_commit": "c3ab3488c602bc797fdc98feffd4578375150dd0",
    "previews": {
      "sheets": [
        "BFD",
        "PFD",
        "P-01",
        "P-02",
        "P-03",
        "P-04",
        "P-05",
        "P-06",
        "P-07",
        "P-08"
      ],
      "source_commit": "c3ab3488c602bc797fdc98feffd4578375150dd0",
      "tool": "cheme 1.6.0 (pyDEXPI 2.1.0)"
    },
    "previews_stale": false,
    "source_commit": "c3ab3488c602bc797fdc98feffd4578375150dd0"
  },
  "publication": {
    "license": "CC-BY-4.0",
    "status": "public"
  },
  "references": [
    {
      "title": "King, C.C., Campagnolo, J.F., Lehman, L.M. (1966) Hydrodealkylation. US Patent 3,291,849 (Hydrocarbon Research, Inc.): per-pass toluene conversion of a thermal HDA reactor",
      "url": "https://patents.google.com/patent/US3291849"
    },
    {
      "title": "Gulf Research & Development Co. (1971) Thermal hydrodealkylation process. US Patent 3,607,960: diphenyl in thermal HDA, primary-reactor benzene selectivity of Example 1",
      "url": "https://patents.google.com/patent/US3607960A/en"
    },
    {
      "title": "Bharat Petroleum Corporation Ltd, toluene data sheet (IS 537:2011): fresh toluene specification",
      "url": "https://bharatpetroleum.in/images/files/Data-Sheet-Toluene.pdf"
    },
    {
      "title": "Matijasevic, L., Petric, M. (2016) Integration of hydrogen systems in petroleum refinery. Chem. Biochem. Eng. Q. 30(3) 291-304, doi:10.15255/CABEQ.2015.2337 (PSA hydrogen purity, recovery and feed limit)"
    },
    {
      "title": "NETL (2022) Comparison of Commercial, State-of-the-Art, Fossil-Based Hydrogen Production Technologies, DOE/NETL-2022/3241: PSA pressures and the PSA package cost scaled for PK-101",
      "url": "https://www.netl.doe.gov/projects/files/ComparisonofCommercialStateofArtFossilBasedHydrogenProductionTechnologies_041222.pdf"
    },
    {
      "title": "Speight, J.G. (2011) Handbook of Industrial Hydrocarbon Processes. Elsevier, Ch. 11 (hydrodealkylation conditions)"
    },
    {
      "title": "Cox, J.D., Wagman, D.D., Medvedev, V.A. (1989) CODATA Key Values for Thermodynamics. Hemisphere (CO2 and H2O formation enthalpies for the LHV)"
    },
    {
      "title": "IDAES HDA flowsheet examples (examples-pse v2.0.0 documentation): cited as a reference model of the route only; no data used",
      "url": "https://idaes.github.io/examples-pse/latest/Tutorials/Basics/HDA_flowsheet_solution_doc.html"
    }
  ],
  "repository": {
    "access": "public",
    "path": "processes/hda-1",
    "url": "https://github.com/ChemE-as-Code/process-library"
  },
  "representations": [
    {
      "bytes": 33881,
      "id": "BFD",
      "kind": "bfd",
      "preview": "artifacts/hda-1/BFD.svg",
      "source": "process/BFD.xml",
      "status": "preview",
      "title": "Block flow diagram"
    },
    {
      "bytes": 172043,
      "id": "PFD",
      "kind": "pfd",
      "preview": "artifacts/hda-1/PFD.svg",
      "source": "process/PFD.xml",
      "status": "preview",
      "title": "Process flow diagram"
    },
    {
      "bytes": 135182,
      "id": "P-01",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-01.svg",
      "source": "pid/P-01.xml",
      "status": "preview",
      "title": "Feed, heater and reactor"
    },
    {
      "bytes": 112637,
      "id": "P-02",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-02.svg",
      "source": "pid/P-02.xml",
      "status": "preview",
      "title": "HP separator and recycle gas"
    },
    {
      "bytes": 74756,
      "id": "P-03",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-03.svg",
      "source": "pid/P-03.xml",
      "status": "preview",
      "title": "Purge PSA and tail gas"
    },
    {
      "bytes": 100396,
      "id": "P-04",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-04.svg",
      "source": "pid/P-04.xml",
      "status": "preview",
      "title": "Stabiliser"
    },
    {
      "bytes": 121186,
      "id": "P-05",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-05.svg",
      "source": "pid/P-05.xml",
      "status": "preview",
      "title": "Benzene column, product"
    },
    {
      "bytes": 120671,
      "id": "P-06",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-06.svg",
      "source": "pid/P-06.xml",
      "status": "preview",
      "title": "Toluene column, biphenyl"
    },
    {
      "bytes": 64247,
      "id": "P-07",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-07.svg",
      "source": "pid/P-07.xml",
      "status": "preview",
      "title": "Flare, nitrogen and fuel headers"
    },
    {
      "bytes": 82711,
      "id": "P-08",
      "kind": "pid",
      "preview": "artifacts/hda-1/P-08.svg",
      "source": "pid/P-08.xml",
      "status": "preview",
      "title": "CW and steam headers"
    },
    {
      "id": "process-model",
      "kind": "process-model",
      "source": "process/flowsheet.yaml",
      "status": "viewer",
      "title": "Flowsheet and stream table"
    },
    {
      "id": "simulation",
      "kind": "simulation",
      "source": "process/simulation.yaml",
      "status": "viewer",
      "title": "Process simulation"
    },
    {
      "id": "layout-3d",
      "kind": "layout-3d",
      "source": "layout/plant-model.yaml",
      "status": "viewer",
      "title": "3D plant layout"
    },
    {
      "id": "equipment-list",
      "kind": "equipment-list",
      "source": "equipment/equipment-list.yaml",
      "status": "viewer",
      "title": "Equipment list"
    },
    {
      "id": "lca",
      "kind": "lca",
      "source": "lca/lca.yaml",
      "status": "viewer",
      "title": "Life cycle assessment"
    }
  ],
  "summary": "Thermal hydrodealkylation of toluene with hydrogen to benzene: adiabatic reactor, quench, HP separator, hydrogen recycle with purge and purge hydrogen recovery (PSA), stabiliser, benzene and toluene columns with toluene recycle and a biphenyl by-product. Concept stage, assumed basis, preliminary LCI (cradle-to-gate study, foreground inventory only).",
  "title": "Toluene hydrodealkylation to benzene (100 kt/a, thermal HDA)",
  "validation": {
    "notes": "Concept PFD with closed mass, component and element balances (cheme validate, cheme process streams), simulated as a whole plant in DWSIM (Peng-Robinson, converged in 13 recycle iterations with the purge hydrogen PSA, D-024). The simulated plant's energy audit closes (residual 0.88 kW against a tolerance of 28.0 kW), but that closure includes 17.4 kW of heat to the isothermal biphenyl step that has no energy stream (a model artefact, D-021) and -4.39 kW stated by the PSA, a specified split (a DWSIM component separator whose recoveries come from a published range, not a prediction, D-024). cheme maturity reports calculation maturity balanced. The feeds are given from published specifications (D-020: a commercial toluene data sheet, BPCL/IS 537:2011, and a PSA hydrogen purity of 99.9 mol%, Matijasevic and Petric 2016). Their flows follow from the design capacity, which is itself ASSUMED (I-04). The reactor R-101 is modelled as a conversion step at the 75 % per-pass toluene conversion of a published thermal HDA reactor (US 3,291,849, adopted as the design value), followed by the biphenyl reaction at chemical equilibrium on the declared formation data (D-021). That equilibrium bounds the biphenyl make only, so the modelled benzene selectivity of 0.973 is optimistic: a published patent example reports 94.5 % at a higher conversion, and the TEA carries it as a scenario. Predictive fails on three requirements: model-basis (R101 is a specified conversion; no readable thermal HDA kinetics with units and range, and no homogeneous kinetic reactor in core), property-regime (core has not benchmarked Peng-Robinson for aromatics with hydrogen and methane) and formation-data (DWSIM's own formation data in the biphenyl equilibrium step). The stabiliser and the benzene column are DWSIM shortcut columns; their product fractions miss 1 by up to 1.7e-4 (core#130). The LCI is a cradle-to-gate study with the foreground inventory only, every background open (8 gaps): no impact result, and no LCA result passed to the catalog (lca.source none). Not reviewed. Main products and feeds are listed under chemistry with their chemicals registry entries (issue #251).",
    "status": "unreviewed"
  },
  "viewer": {
    "commit": "c3ab3488c602bc797fdc98feffd4578375150dd0",
    "dirty": false,
    "sheets": [
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      "pid/P-04.xml",
      "pid/P-05.xml",
      "pid/P-06.xml",
      "pid/P-07.xml",
      "pid/P-08.xml",
      "process/BFD.xml",
      "process/PFD.xml"
    ],
    "skipped": [],
    "snapshot": "snapshots/hda-1/",
    "stale": false,
    "tool": "cheme-as-code 1.6.0",
    "views": [
      "checks",
      "layout",
      "mto",
      "streams"
    ]
  }
}