{
  "authors": [],
  "basis": {
    "capacity": "670.6 t/a dried NaN3: 652.6 batches/a of 1027.6 kg in 7920 h on a dedicated train (84.68 kg/h year average), ASSUMED (DESIGN.md D-002, D-003, D-014)",
    "location": "generic fine-chemicals site with a thermal oxidiser and an azide-capable wastewater treatment (not chosen)",
    "operating_hours_per_year": 7920
  },
  "benchmarks": [
    {
      "dataset": "sodium-azide-by-the-hydrazine-methyl-nitrite-route-batch-with-precipitation-from-the-reaction-liquor",
      "expression": "feed:HH / product:NAN3P",
      "family": "inorganic-chemicals",
      "kpi": "nan3-specific-hydrazine-hydrate",
      "problem": "1 to kg/kg needs core's foundation.units (pip install 'cheme-as-code[units]')",
      "reference": {
        "basis": "unallocated",
        "conditions": {
          "product": "dried sodium azide, 99.5 wt%",
          "region": "laboratory to pilot scale (20 L)",
          "technology": "methyl nitrite absorbed into aqueous hydrazine and caustic soda at 30 C, NaN3 crystallised from the concentrated liquor, filtrate recycled (11 batches)",
          "year": 1993
        },
        "id": "us5208002-example2",
        "note": "A patent example, not a plant: the dataset takes its charge ratios from the same patent's Example 1 (DESIGN.md D-004), but its yield on hydrazine (92 %) follows from its own recycle, purge and losses, so the range checks the balance, not a transcription.",
        "range": [
          0.807,
          0.852
        ],
        "source": {
          "accessed": "2026-11-05",
          "citation": "Sasaki, M. et al. (Nippon Carbide Industries, 1993) US 5 208 002 A, Method of producing alkali metal azides (family EP 0 514 143 B1; priority 1991-05-17)",
          "kind": "other",
          "locator": "Example 2 and Table 2: the steady cycles 4-11 (43.2 mol hydrazine added for 41.0 mol NaN3) give the low end, the 11 cycles together (493.8 mol hydrazine, 444.2 mol NaN3 at 99.5 %, 90.0 % yield) the high end; converted by us to kg of 64 wt% hydrate per kg of product",
          "url": "https://patents.google.com/patent/US5208002A/en"
        }
      },
      "status": "unchecked",
      "title": "Hydrazine hydrate (64 wt% N2H4) per kg of sodium azide",
      "unit": "kg/kg",
      "value": null
    },
    {
      "dataset": "sodium-azide-by-the-hydrazine-methyl-nitrite-route-batch-with-precipitation-from-the-reaction-liquor",
      "expression": "product:OFFGAS / product:NAN3P",
      "family": "inorganic-chemicals",
      "kpi": "nan3-specific-offgas",
      "no_open_reference": "No open source with the off-gas (unabsorbed methyl nitrite, N2O, NH3) of a sodium azide plant found (searched 2026-11-05: Google Patents US 5 208 002 A and US 5 098 597 A read, which name the nitrogen of side reactions but give no off-gas amounts; J. Studley, Scientific Update 2023, a secondary summary without figures). The dataset's off-gas follows from the methyl nitrite not absorbed in the patent's Example 1 balance and its ASSUMED side reaction (DESIGN.md D-004, D-005).",
      "problem": "1 to kg/kg needs core's foundation.units (pip install 'cheme-as-code[units]')",
      "reference": null,
      "status": "unchecked",
      "title": "Azide reactor off-gas to treatment per kg of sodium azide",
      "unit": "kg/kg",
      "value": null
    }
  ],
  "chemistry": {
    "inputs": [
      {
        "chemical": "sodium-nitrite",
        "grade": null,
        "inventory_key": "feed:NANO2",
        "note": "Dried sodium nitrite (sodium-nitrite-1), dissolved in R-101's charge, 1.222 kg/kg NaN3",
        "role": "feedstock"
      },
      {
        "chemical": "sulfuric-acid",
        "grade": null,
        "inventory_key": "feed:ACID",
        "note": "Sulfuric acid 98.5 wt% (sulfuric-acid-1), dosed into R-101, 0.883 kg/kg NaN3",
        "role": "feedstock"
      },
      {
        "chemical": "hydrazine",
        "grade": null,
        "inventory_key": "feed:HH",
        "note": "Hydrazine hydrate 64 wt% N2H4 (hydrazine-1), 0.831 kg/kg NaN3 as hydrate",
        "role": "feedstock"
      },
      {
        "chemical": "sodium-hydroxide",
        "grade": null,
        "inventory_key": "feed:NAOH",
        "note": "Caustic soda 50 wt% (chlor-alkali-1), 1.287 kg/kg NaN3 as solution",
        "role": "feedstock"
      },
      {
        "chemical": "methanol",
        "grade": null,
        "inventory_key": "feed:MEOH",
        "note": "Methanol make-up (methanol-1) of the methanol loop, 0.074 kg/kg NaN3; the methanol itself is recovered and reused",
        "role": "feedstock"
      },
      {
        "chemical": "water",
        "grade": null,
        "inventory_key": "feed:PW1",
        "note": "Process water to R-101's charge, 3.05 kg/kg NaN3",
        "role": "feedstock"
      },
      {
        "chemical": "water",
        "grade": null,
        "inventory_key": "feed:PW2",
        "note": "Process water to R-102's charge, 1.38 kg/kg NaN3",
        "role": "feedstock"
      },
      {
        "chemical": "nitrogen",
        "grade": null,
        "inventory_key": "consumable:nitrogen",
        "note": "Nitrogen (asu-1) for inerting, vacuum breaks and pressure filtration, 50 kg per batch, 0.049 kg/kg NaN3 (ASSUMED)",
        "role": "feedstock"
      }
    ],
    "outputs": [
      {
        "chemical": "sodium-azide",
        "grade": null,
        "inventory_key": "product:NAN3P",
        "note": "Dried sodium azide, 99.6 wt% NaN3, to packing",
        "role": "main-product"
      },
      {
        "chemical": "wastewater",
        "grade": null,
        "inventory_key": "product:SULF",
        "note": "Sodium sulfate liquor of the nitrite generator, 4.72 kg/kg NaN3, to wastewater treatment",
        "role": "waste"
      },
      {
        "chemical": "wastewater",
        "grade": null,
        "inventory_key": "product:COND",
        "note": "Evaporator condensate (water, 0.12 wt% methanol), 2.78 kg/kg NaN3, to wastewater treatment",
        "role": "waste"
      },
      {
        "chemical": "wastewater",
        "grade": null,
        "note": "Mother-liquor purge (product:PURGE: NaOH, hydrazine, 8 wt% NaN3), 0.086 kg/kg NaN3, to azide destruction (hydrazine oxidised first) and wastewater treatment; an LCI gap",
        "role": "waste"
      },
      {
        "chemical": "nitrous-oxide",
        "grade": null,
        "note": "R-102's off-gas (product:OFFGAS, 0.138 kg/kg NaN3) to the thermal oxidiser: methyl nitrite 64, N2O 26, NH3 10 wt%; 0.036 kg N2O per kg NaN3, whose fate in the oxidiser is open (DESIGN.md D-013)",
        "role": "emission"
      }
    ],
    "utilities": [
      {
        "chemical": "electricity",
        "grade": null,
        "inventory_key": "feed:POWER",
        "note": "0.154 kWh/kg NaN3: agitators, gas dispersion, vacuum pumps (ASSUMED)",
        "role": "utility"
      },
      {
        "chemical": "steam",
        "grade": null,
        "inventory_key": "feed:LPS",
        "note": "2.30 kWh/kg NaN3 of LP steam 350 kPa(a), through tempered hot water: the still's boil-up and the filter-dryer",
        "role": "utility"
      },
      {
        "chemical": "chilled-water",
        "grade": null,
        "inventory_key": "product:CHW",
        "note": "2.08 kWh/kg NaN3 removed by chilled water at 278-283 K: R-101, R-102 and the methanol condensers",
        "role": "utility"
      },
      {
        "chemical": "cooling-water",
        "grade": null,
        "inventory_key": "product:CW",
        "note": "1.98 kWh/kg NaN3: the still's water condenser and the crystallizer, 25/35 C (ASSUMED)",
        "role": "utility"
      }
    ]
  },
  "description": "The route of US 5 208 002 A (Nippon Carbide, 1993): in R-101, 98.5 % sulfuric acid is dosed\nover 10 h into aqueous sodium nitrite with an equimolar amount of methanol at 298 K, and the\nmethyl nitrite gas formed passes straight into R-102. There it is absorbed (91.8 %, the share\nthe patent's Example 1 balance accounts for) into hydrazine hydrate and caustic soda (1.20 mol\nNaOH per mol hydrazine) together with the mother liquor of the previous batch at 313 K, and\ngives sodium azide and methanol; about 5 % of the hydrazine consumed is lost to ammonia and\nnitrous oxide (95 % selectivity at the patent's 70 % conversion). The acid side and the azide\nside never share a vessel or a liquor, so the azide never meets acid; hydrazine carried in the\nrecovered methanol would form HN3 in R-101, so that methanol has a hydrazine limit (D-015). The\nliquor is stripped of\nmethanol and concentrated at 10 kPa(a) in the batch still C-101 (the methanol cut, 88 wt%,\ngoes back to R-101 and to the cake wash; the residue ends at about 360 K, estimated with the\ncaustic liquor's boiling-point elevation, an open reaction-hazard item), NaN3 precipitates at 303\nK from the concentrated\ncaustic liquor (39 wt% NaOH, 17 wt% hydrazine), and the agitated filter-dryer F-101 filters\nit, washes it with methanol (0.43 kg/kg) and dries it at 333 K under vacuum. The mother\nliquor, the wash filtrate and the dryer condensate go back to R-102, less a 5 % purge to azide\ndestruction (the hydrazine oxidised first, then the azide with nitrite and acid). Product 99.6 wt% NaN3; yield 92.3 % on hydrazine. Per kg NaN3: sodium nitrite\n1.222 kg, sulfuric acid 0.883 kg, hydrazine hydrate (64 %) 0.831 kg, caustic soda (50 %)\n1.287 kg, methanol 0.074 kg; 0.036 kg N2O leaves in the off-gas to the thermal oxidiser.\n\nIt is the library's first entry on core's batch work-up models: R-101 and R-102 are\nsemi-batches with their gas vents (batch.vent, dosing.absorbed; core ADR 0054), C-101 a batch\nRayleigh still with two cuts (ADR 0055), the precipitation a crystallizer with spectator\nsolutes and a solubility measured in the patent's mother liquor (ADR 0056), and F-101 a\nfilter-dryer over four steps with its filtration and drying times (ADR 0057). R-102's jacket\nsets the 10 h dosing; R-102 is the bottleneck (cycle 12.14 h, 652.6 batches a year). The\nkinetics are ASSUMED (no open data): the dissolved methyl nitrite accumulates to 2.0 % and the\ncooling-failure temperature stays at 318.9 K, below the 337.6 K boiling point of methanol, but\na ten times slower reaction would exceed it. The gas a cooling failure releases at the MTSR is\nwithin the vents (ASSUMED 50 and 60 m3/h), but a blocked vent pressurises R-101 or R-102: the acid\ndosing trips on pressure, and each reactor needs a relief device. See DESIGN.md for every assumption, the process\nsafety notes (azide toxicity, hydrazoic acid from azide and from hydrazine, heavy-metal azides,\nmethyl nitrite, the hot concentrated liquor) and the core\nlimits met.\n",
  "design_basis": {
    "assumptions": [
      "Route: methyl nitrite generated from sodium nitrite, methanol and sulfuric acid in its own vessel and absorbed into aqueous hydrazine and caustic soda; NaN3 crystallised from the concentrated liquor, methanol recovered, the filtrate recycled (US 5 208 002 A, D-001).",
      "Charge ratios from US 5 208 002 Example 1 (D-004): 1.20 mol NaOH, 0.769 mol NaNO2 and 6.63 mol water per mol hydrazine; 0.501 mol H2SO4 and 1.002 mol methanol per mol NaNO2; 91.8 % of the methyl nitrite absorbed; 95 % selectivity on hydrazine (D-005).",
      "ASSUMED fast effective rate laws for both semi-batches (D-005): no open kinetics; the low accumulation follows from them (D-011).",
      "Heats of reaction from pure-substance formation enthalpies (chemicals: CRC, ATcT, NIST WebBook), heats of solution not counted (D-005).",
      "ASSUMED jackets: U 400 W/(m2 K) on chilled water at 278-283 K; R-102's jacket sets the 10 h dosing (D-010).",
      "Effective relative volatility of methanol to water 150 in the one-stage still, calibrated to the patent's 90 wt% methanol cut (D-007); NaN3 solubility measured in the patent's mother liquor (D-008).",
      "5 % of the mother liquor purged per batch (D-016).",
      "All flows are year averages of the recipe (D-003); duties from core's models, power ASSUMED (D-012); accuracy +/-30 % not demonstrated."
    ],
    "source": "process/design-basis.yaml"
  },
  "engineering": {
    "description": "Sodium azide by the hydrazine / methyl nitrite route (methyl nitrite from sodium nitrite, methanol and sulfuric acid, absorbed into hydrazine and caustic soda), precipitation from the concentrated reaction liquor, filter-dryer and mother-liquor recycle, a batch plant, concept stage (issue ChemE-as-Code/process-library#167)",
    "name": "Sodium azide",
    "requires": "cheme-as-code>=1.9",
    "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",
      "mineral",
      "electricity"
    ],
    "product_classes": [
      "chemicals"
    ],
    "region": "generic",
    "unit_operations": [
      "reaction",
      "absorption",
      "distillation",
      "crystallization",
      "filtration",
      "drying"
    ]
  },
  "families": [
    "inorganic-chemicals"
  ],
  "gap_count": 3,
  "gates": null,
  "id": "sodium-azide-1",
  "issues": {
    "closed_count": 0,
    "list_url": "https://github.com/ChemE-as-Code/process-library/issues?q=is%3Aissue%20label%3A%22process%3Asodium-azide-1%22",
    "new": {
      "action": "https://github.com/ChemE-as-Code/process-library/issues/new?template=1-action-item.yml&labels=process%3Asodium-azide-1&process=sodium-azide-1",
      "change": "https://github.com/ChemE-as-Code/process-library/issues/new?template=4-design-change.yml&labels=process%3Asodium-azide-1&process=sodium-azide-1",
      "hold": "https://github.com/ChemE-as-Code/process-library/issues/new?template=2-engineering-hold.yml&labels=process%3Asodium-azide-1&process=sodium-azide-1",
      "process": "https://github.com/ChemE-as-Code/process-library/issues/new?template=6-process-development.yml&labels=process%3Asodium-azide-1&process=sodium-azide-1",
      "tq": "https://github.com/ChemE-as-Code/process-library/issues/new?template=3-technical-query.yml&labels=process%3Asodium-azide-1&process=sodium-azide-1",
      "tracker": "https://github.com/ChemE-as-Code/process-library/issues/new?template=7-process-tracker.yml&labels=process%3Asodium-azide-1&process=sodium-azide-1"
    },
    "open": [],
    "open_by_gate": {},
    "open_count": 0,
    "private": false,
    "repository": "ChemE-as-Code/process-library"
  },
  "keywords": [
    "sodium azide",
    "NaN3",
    "hydrazine",
    "methyl nitrite",
    "alkyl nitrite",
    "sodium nitrite",
    "azide",
    "semi-batch",
    "batch",
    "gas dosing",
    "vent",
    "batch distillation",
    "precipitation",
    "filter-dryer",
    "mother-liquor recycle",
    "thermal screening"
  ],
  "lca": {
    "allocation": null,
    "backend": "factors",
    "boundary": "cradle-to-gate",
    "categories": [
      {
        "id": "climate-change",
        "method": "GWP100",
        "title": "Climate change",
        "unit": "kg CO2-eq"
      }
    ],
    "contributions": [],
    "data_sources": [],
    "factors_status": "none",
    "functional_unit": {
      "amount": 1,
      "chemical": "sodium-azide",
      "grade": null,
      "label": "1 kg sodium azide",
      "product": "NAN3P",
      "product_name": "Sodium azide",
      "product_title": "Dried sodium azide to packing",
      "unit": "kg"
    },
    "goal": "Preliminary gate-to-gate life cycle inventory of sodium azide made by the batch hydrazine / methyl nitrite route (methyl nitrite from sodium nitrite, methanol and sulfuric acid, absorbed into hydrazine and caustic soda; NaN3 precipitated from the concentrated liquor, filtered, washed with methanol and dried, the mother liquor recycled) at the concept stage: which raw materials, utilities and wastes the batch plant exchanges per kg of dried NaN3, as the foreground for a later cradle-to-gate study. No impact results: most utility and treatment backgrounds are not mapped yet (D-013).",
    "inventory": [
      {
        "direction": "input",
        "key": "feed:NANO2",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 1.22183,
        "title": "Sodium nitrite (sodium-nitrite-1)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:PW1",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 3.05143,
        "title": "Process water (nitrite generator)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:ACID",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 0.883422,
        "title": "Sulfuric acid 98.5 wt% (sulfuric-acid-1)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:HH",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 0.83146,
        "title": "Hydrazine hydrate 64 wt% N2H4 (hydrazine-1)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:NAOH",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 1.28681,
        "title": "Caustic soda 50 wt% (chlor-alkali-1)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:PW2",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 1.37683,
        "title": "Process water (azide reactor)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:MEOH",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 0.0739593,
        "title": "Methanol make-up (methanol-1)",
        "unit": "kg"
      },
      {
        "direction": "input",
        "key": "feed:POWER",
        "kind": "energy",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 0.153524,
        "title": "Electric power",
        "unit": "kWh"
      },
      {
        "direction": "input",
        "key": "feed:LPS",
        "kind": "energy",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 2.29686,
        "title": "LP steam 350 kPa(a) (still and filter-dryer)",
        "unit": "kWh"
      },
      {
        "direction": "output",
        "key": "product:NAN3P",
        "kind": "material",
        "phase": "operation",
        "provenance": "calculated",
        "quantity": 1.0,
        "title": "Dried sodium azide to packing",
        "unit": "kg"
      },
      {
        "direction": "output",
        "key": "product:SULF",
        "kind": "material",
        "phase": "operation",
        "provenance": "calculated",
        "quantity": 4.71993,
        "title": "Sodium sulfate liquor to wastewater treatment",
        "unit": "kg"
      },
      {
        "direction": "output",
        "key": "product:COND",
        "kind": "material",
        "phase": "operation",
        "provenance": "calculated",
        "quantity": 2.78146,
        "title": "Evaporator condensate to wastewater treatment",
        "unit": "kg"
      },
      {
        "direction": "output",
        "key": "product:PURGE",
        "kind": "material",
        "phase": "operation",
        "provenance": "calculated",
        "quantity": 0.0862217,
        "title": "Mother-liquor purge to azide destruction and wastewater treatment",
        "unit": "kg"
      },
      {
        "direction": "output",
        "key": "product:OFFGAS",
        "kind": "material",
        "phase": "operation",
        "provenance": "calculated",
        "quantity": 0.138116,
        "title": "Azide reactor off-gas to the thermal oxidiser",
        "unit": "kg"
      },
      {
        "direction": "output",
        "key": "product:CHW",
        "kind": "energy",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 2.08133,
        "title": "Chilled water return (R-101, R-102 and the methanol condensers)",
        "unit": "kWh"
      },
      {
        "direction": "output",
        "key": "product:CW",
        "kind": "energy",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 1.98356,
        "title": "Cooling water return (still's water condenser and crystallizer)",
        "unit": "kWh"
      },
      {
        "direction": "input",
        "key": "consumable:nitrogen",
        "kind": "material",
        "phase": "operation",
        "provenance": "assumed",
        "quantity": 0.0486548,
        "title": "Nitrogen for inerting R-101 and R-102, breaking C-101's vacuum and the pressure filtrations of F-101",
        "unit": "kg"
      }
    ],
    "no_total": {
      "baseline": {
        "climate-change": {
          "gaps": 16,
          "reason": "every-contribution-a-gap"
        }
      }
    },
    "not_computed": [
      "climate-change"
    ],
    "pcf": [],
    "publishable": true,
    "result": {
      "classification": "partial",
      "gaps": 16,
      "label": "partial screening carbon footprint",
      "publication": "public"
    },
    "sources": [
      "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"
    ],
    "totals": {
      "baseline": {}
    },
    "withheld_reason": null
  },
  "lci_gaps": [
    {
      "dataset": "sodium-azide-by-the-hydrazine-methyl-nitrite-route-batch-with-precipitation-from-the-reaction-liquor",
      "key": "product:PURGE",
      "link": "technosphere",
      "type": "output"
    },
    {
      "dataset": "sodium-azide-by-the-hydrazine-methyl-nitrite-route-batch-with-precipitation-from-the-reaction-liquor",
      "key": "product:OFFGAS",
      "link": "technosphere",
      "type": "output"
    },
    {
      "dataset": "sodium-azide-by-the-hydrazine-methyl-nitrite-route-batch-with-precipitation-from-the-reaction-liquor",
      "key": "product:CHW",
      "link": "technosphere",
      "type": "output"
    }
  ],
  "maintainers": [
    {
      "name": "Artur Schweidtmann"
    }
  ],
  "maturity": "concept",
  "preliminary": true,
  "provenance": {
    "library_commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174",
    "previews": {
      "sheets": [
        "BFD",
        "PFD"
      ],
      "source_commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174",
      "tool": "cheme 1.6.0 (pyDEXPI 2.1.0)"
    },
    "previews_stale": false,
    "source_commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174"
  },
  "publication": {
    "license": "CC-BY-4.0",
    "status": "public"
  },
  "references": [
    {
      "title": "Sasaki, M.; Shibafuchi, H.; Imai, Y.; Yoshida, M.; Miyata, K. (Nippon Carbide Industries, 1993) US 5 208 002 A, Method of producing alkali metal azides (family EP 0 514 143 B1; priority 1991-05-17): claims, Examples 1-4 and Tables 1-3 (charges, conditions, conversion and selectivity, work-up, filtrate composition, recycle, yields)",
      "url": "https://patents.google.com/patent/US5208002A/en"
    },
    {
      "title": "US 5 098 597 A (Olin, 1992), continuous process for sodium azide with ethyl nitrite generated apart from the azide reactor (alternative read for the route choice)",
      "url": "https://patents.google.com/patent/US5098597A/en"
    },
    {
      "title": "PubChem CID 33557, Sodium azide (identity)",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/33557"
    },
    {
      "title": "NIST Chemistry WebBook, SRD 69: Antoine parameters of water (Stull 1947) and methanol",
      "url": "https://webbook.nist.gov/chemistry/"
    },
    {
      "doi": "10.1002/9783527621606",
      "title": "Stoessel, F. (2008) Thermal Safety of Chemical Processes, Wiley-VCH (accumulation and MTSR of a semi-batch; method reference, not data)"
    }
  ],
  "repository": {
    "access": "public",
    "path": "processes/sodium-azide-1",
    "url": "https://github.com/ChemE-as-Code/process-library"
  },
  "representations": [
    {
      "bytes": 43796,
      "id": "BFD",
      "kind": "bfd",
      "preview": "artifacts/sodium-azide-1/BFD.svg",
      "source": "process/BFD.xml",
      "status": "preview",
      "title": "Block flow diagram"
    },
    {
      "bytes": 172377,
      "id": "PFD",
      "kind": "pfd",
      "preview": "artifacts/sodium-azide-1/PFD.svg",
      "source": "process/PFD.xml",
      "status": "preview",
      "title": "Process flow diagram"
    },
    {
      "id": "process-model",
      "kind": "process-model",
      "source": "process/flowsheet.yaml",
      "status": "viewer",
      "title": "Flowsheet and stream table"
    },
    {
      "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": "A batch plant: methyl nitrite from sodium nitrite, methanol and sulfuric acid is absorbed into hydrazine and caustic soda; sodium azide precipitates from the concentrated liquor and is filtered, washed and dried in a filter-dryer, the mother liquor recycled. Concept stage, 1028 kg per batch every 12.1 h, thermal screening, preliminary LCI.",
  "title": "Sodium azide by the hydrazine / methyl nitrite route, batch, with precipitation from the reaction liquor (670 t/a)",
  "validation": {
    "notes": "Concept batch PFD with closed mass, component and element balances (cheme validate: 4 blocks and 13 steps within tolerance). Calculated by cheme process propagate with core 1.9.0: the two vented semi-batches R101 and R102 from their ASSUMED rate laws, the batch still ST101 (constant relative volatility, ASSUMED), the precipitation CR101 from a solubility measured in the patent's mother liquor, the specified filters and the dryer; the two recycles (methanol to R-101, mother liquor to R-102) converged by propagate at the tear streams S3 and S11 (Wegstein, 32 iterations), the fresh feeds ASSUMED at the charge ratios; the duties of R101, R102, the still's boil-up and the crystallizer written by their models. The recipe's year-average product rate agrees with the flowsheet (no cheme.recipe-basis finding); the recipe sizes R-101 (6.3 m3), R-102 (8 m3) and F-101 (2 m3), both jacket checks pass. Thermal screening (cheme process reactor-hazards): R-102 dT_ad 307 K, accumulation 1.98 %, MTSR 318.9 K against an MTT of 337.63 K (core's default: methanol's boiling point); R-101 dT_ad 43 K, MTSR 298.6 K; the gas release at the MTSR 29.4 m3/h (R-101) and 6.3 m3/h (R-102) against ASSUMED vent capacities of 50 and 60 m3/h; the pressure of a blocked vent is estimated by hand (a design finding: pressure trip and relief); no criticality class without a TD24 from calorimetry (none estimated). Preliminary gate-to-gate LCI with the per-batch nitrogen; the purchased feeds linked to their library producers, utilities and treatments gaps. cheme maturity reaches no level (assumed feeds, kinetics and separations); the claim `maturity: concept` is the lowest value of the schema, not an evidenced level. Not reviewed. Needs cheme-as-code 1.9.",
    "status": "unreviewed"
  },
  "viewer": {
    "commit": "a3c52e472f42fbc8cdacfeacf5ef28703c004174",
    "dirty": false,
    "sheets": [
      "process/BFD.xml",
      "process/PFD.xml"
    ],
    "skipped": [],
    "snapshot": "snapshots/sodium-azide-1/",
    "stale": false,
    "tool": "cheme-as-code 1.6.0",
    "views": [
      "checks"
    ]
  }
}