{ "authors": [], "basis": { "capacity": "100 kt/a methyl chloride (ASSUMED)", "location": "generic (not chosen)", "operating_hours_per_year": 8000 }, "benchmarks": [], "chemistry": { "inputs": [ { "chemical": "methanol", "grade": null, "note": "feed:MEOH: methanol (e.g. methanol-1 product grade), 0.646 kg/kg", "role": "feedstock" }, { "chemical": "hydrogen-chloride", "grade": null, "note": "feed:HCLG: anhydrous hydrogen chloride gas, 0.823 kg/kg", "role": "feedstock" }, { "chemical": "sulfuric-acid", "grade": null, "note": "feed:ACID: sulfuric acid 96 wt% for drying", "role": "feedstock" }, { "chemical": "nitrogen", "grade": null, "note": "Inerts of the anhydrous HCl feed (0.1 mol%, ASSUMED)", "role": "feedstock" } ], "outputs": [ { "chemical": "chloromethane", "grade": null, "inventory_key": "product:MECL", "note": "Methyl chloride, liquid, to storage", "role": "main-product" }, { "chemical": "nitrogen", "grade": null, "note": "Inerts in the purge (product:PURGE, 5.0 g/kg, to the site thermal oxidiser, a waste exchange). The dilute hydrochloric acid (product:DHCL, 0.447 kg/kg) and the spent sulfuric acid (product:SPENT, 69 g/kg) are not listed under chemistry yet", "role": "emission" } ], "utilities": [ { "chemical": "electricity", "grade": null, "inventory_key": "feed:POWER", "note": "0.044 kWh/kg: methyl chloride compressor and pumps (hand estimate)", "role": "utility" }, { "chemical": "steam", "grade": null, "inventory_key": "feed:LPS", "note": "LP steam 500 kPa(a), 0.263 kWh/kg: methanol vaporiser (net of reactor heat), stripper and HCl column reboilers", "role": "utility" }, { "chemical": "cooling-water", "grade": null, "inventory_key": "product:CW", "note": "0.649 kWh/kg, 25/35 C (ASSUMED); the quench is 69 % of it", "role": "utility" } ] }, "description": "Fresh methanol and the methanol recovered from the quench acid are vaporised and mixed with\nanhydrous HCl (HCl/MeOH 1.10 at the inlet) and the recycle from the HCl column. The feed is\nsuperheated by the reactor coolant loop and reacts in a multitubular fixed bed of\ngamma-alumina (523 K in, 613 K out, about 300 kPa(a)); 97.6 % of the methanol is converted\nper pass, 98.8 % of it to methyl chloride and the rest to dimethyl ether (DME). A\nhydrochloric acid quench and a graphite cooler condense the water of reaction with the\nexcess HCl as about 21 wt% acid; a stripper returns the dissolved methanol, and the dilute\nacid leaves the plant. Sulfuric acid (96 wt%) dries the crude gas and absorbs the DME, since\nDME and methyl chloride boil only 1 K apart. A two-stage compressor and a water-cooled\ncondenser liquefy the methyl chloride at about 1 MPa, and an HCl column strips the dissolved\nHCl and inerts overhead; the overhead returns to the reactor with a 10 % purge.\n\nAll values are concept estimates: the conversion and selectivity are one open literature data\npoint (near equilibrium, checked with cheme process reactors), the separator splits are\nASSUMED and checked against the crude-gas, quench-acid and spent-acid ranges of US 4,794,204;\nthe utilities are hand estimates. See DESIGN.md for every assumption and gated step.\n", "design_basis": { "assumptions": [ "Route: gas-phase hydrochlorination of methanol over gamma-alumina, water quench, sulfuric acid drying, compression and distillation (D-001).", "ASSUMED reactor: HCl/MeOH 1.10 mol/mol at the inlet, 523 K in, 613 K out, 350/300 kPa(a) (WO 2000/076658: about equimolar, 250-300 C, 1-10 bar) (D-004, D-005).", "Reactor model: methanol conversion 0.976 and CH3Cl selectivity 0.988 per pass (Schmidt et al. 2014, best result at 340 C, near equilibrium); rest to DME. A sourced conversion model, not kinetics (D-004).", "ASSUMED quench/condensation to 313 K, 200 kPa(a); crude gas 0.5 mol% HCl and water from a water activity of 0.7 over the acid (D-006).", "ASSUMED methanol stripper: 99 % methanol recovery, returned to the vaporiser (D-007).", "ASSUMED drying: 96 wt% acid at a rate giving 8 wt% DME in the spent acid (limit 5-10 %, US 4,794,204) (D-008).", "ASSUMED HCl column: overhead 70 mol% CH3Cl, recycled to the reactor with a 10 % purge for the inerts (D-009).", "Utilities are hand estimates (scripts/balance.py), not a rigorous energy balance: no property package qualified for HCl-water-methanol (D-010, D-011)." ], "source": "process/design-basis.yaml" }, "engineering": { "description": "Chloromethane (methyl chloride) by gas-phase hydrochlorination of methanol over alumina; concept PFD and preliminary LCI (issue ChemE-as-Code/process-library#151)", "name": "Chloromethane (methanol hydrochlorination)", "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", "absorption", "distillation", "compression" ] }, "families": [ "chlorinated-organics" ], "gap_count": 5, "gates": null, "id": "chloromethane-1", "issues": { "closed_count": 0, "list_url": "https://github.com/ChemE-as-Code/process-library/issues?q=is%3Aissue%20label%3A%22process%3Achloromethane-1%22", "new": { "action": "https://github.com/ChemE-as-Code/process-library/issues/new?template=1-action-item.yml&labels=process%3Achloromethane-1&process=chloromethane-1", "change": "https://github.com/ChemE-as-Code/process-library/issues/new?template=4-design-change.yml&labels=process%3Achloromethane-1&process=chloromethane-1", "hold": "https://github.com/ChemE-as-Code/process-library/issues/new?template=2-engineering-hold.yml&labels=process%3Achloromethane-1&process=chloromethane-1", "process": "https://github.com/ChemE-as-Code/process-library/issues/new?template=6-process-development.yml&labels=process%3Achloromethane-1&process=chloromethane-1", "tq": "https://github.com/ChemE-as-Code/process-library/issues/new?template=3-technical-query.yml&labels=process%3Achloromethane-1&process=chloromethane-1", "tracker": "https://github.com/ChemE-as-Code/process-library/issues/new?template=7-process-tracker.yml&labels=process%3Achloromethane-1&process=chloromethane-1" }, "open": [], "open_by_gate": {}, "open_count": 0, "private": false, "repository": "ChemE-as-Code/process-library" }, "keywords": [ "chloromethane", "methyl chloride", "methanol", "hydrogen chloride", "hydrochlorination", "alumina", "dimethyl ether", "sulfuric acid drying", "compression", "distillation", "silicones" ], "lca": null, "lci_gaps": [ { "dataset": "chloromethane-from-methanol-and-hydrogen-chloride-gas-phase-hydrochlorination", "key": "feed:MEOH", "link": "technosphere", "type": "input" }, { "dataset": "chloromethane-from-methanol-and-hydrogen-chloride-gas-phase-hydrochlorination", "key": "feed:HCLG", "link": "technosphere", "type": "input" }, { "dataset": "chloromethane-from-methanol-and-hydrogen-chloride-gas-phase-hydrochlorination", "key": "product:DHCL", "link": "technosphere", "type": "output" }, { "dataset": "chloromethane-from-methanol-and-hydrogen-chloride-gas-phase-hydrochlorination", "key": "product:SPENT", "link": "technosphere", "type": "output" }, { "dataset": "chloromethane-from-methanol-and-hydrogen-chloride-gas-phase-hydrochlorination", "key": "product:PURGE", "link": "technosphere", "type": "output" } ], "maintainers": [], "maturity": "concept", "preliminary": true, "provenance": { "library_commit": "c3ab3488c602bc797fdc98feffd4578375150dd0", "previews": { "sheets": [ "BFD", "PFD" ], "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": "US 4,794,204 (Hoechst, 1988) Process for the removal of dimethyl ether in methyl chloride (background: alumina process at 350-400 C, crude gas composition, sulfuric acid drying with 95 % acid, spent acid about 80 % with 5-10 % DME; plant embodiment: HCl quench and graphite cooler)", "url": "https://patents.google.com/patent/US4794204" }, { "doi": "10.1515/gps-2014-0039", "title": "Schmidt, S.A., Vajglova, Z., Eränen, K., Murzin, D.Yu., Salmi, T. (2014) Microreactor technology for on-site production of methyl chloride. Green Processing and Synthesis 3(5) 345-352 (abstract read)" }, { "title": "WO 2000/076658 A1 (ICI/Ineos Chlor) Use of alkali metal doped eta-alumina as methanol hydrochlorination catalyst (background: equimolar feed, 250-300 C, hot spots, DME main by-product; claims: 1-10 bara)", "url": "https://patents.google.com/patent/WO2000076658A1/en" }, { "doi": "10.1002/14356007.a06_233.pub4", "title": "Chloromethanes. Ullmann's Encyclopedia of Industrial Chemistry (issue #151 lead; licensed, not read in this run)" } ], "repository": { "access": "public", "path": "processes/chloromethane-1", "url": "https://github.com/ChemE-as-Code/process-library" }, "representations": [ { "bytes": 35119, "id": "BFD", "kind": "bfd", "preview": "artifacts/chloromethane-1/BFD.svg", "source": "process/BFD.xml", "status": "preview", "title": "Block flow diagram" }, { "bytes": 122326, "id": "PFD", "kind": "pfd", "preview": "artifacts/chloromethane-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": "Methanol and anhydrous hydrogen chloride react over alumina to methyl chloride and water; the gas is quenched, dried with sulfuric acid (which also takes up the dimethyl ether by-product), compressed, condensed and freed of HCl in a light-ends column. Concept stage, assumed basis, preliminary gate-to-gate LCI per kg methyl chloride (foreground only).", "title": "Chloromethane from methanol and hydrogen chloride (gas-phase hydrochlorination, 100 kt/a)", "validation": { "notes": "Concept PFD (4 blocks, 12 steps, 19 material and 13 energy streams, two recycles and an inert purge) with closed mass, component and element balances (cheme validate, cheme process streams: every block and step within tolerance). The reactor outlet is calculated by cheme from a sourced conversion and selectivity (Schmidt et al. 2014); its hydrochlorination quotient is 0.91 of the equilibrium constant (cheme process reactors), consistent with the source's near-equilibrium statement. Crude gas DME 0.56 mol%, quench acid 20.5 wt% HCl and spent acid 80.5 % fall inside the ranges of US 4,794,204. Fresh methanol 0.646 kg and HCl 0.823 kg per kg methyl chloride (stoichiometric 0.635 and 0.722). No rigorous energy balance: no property package covers HCl-water-methanol (electrolyte); duties are hand estimates; the reactor duty agrees with cheme's ideal-gas duty within 1.5 %. cheme maturity reaches no level. The LCI is foreground only, every background a gap (9 gaps): no impact result (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": [ "process/BFD.xml", "process/PFD.xml" ], "skipped": [], "snapshot": "snapshots/chloromethane-1/", "stale": false, "tool": "cheme-as-code 1.6.0", "views": [ "checks", "streams" ] } }