Vinyl chloride monomer: Production route
Ethylene or coal: two very different ways to make it
What this tab covers How it is made: the main production routes or, for product families, the main product types and technologies, compared on share of supply, inputs per tonne, plant scale, yield, co-products and unit cost.Two routes dominate. Outside China, the balanced ethylene route makes EDC by direct chlorination and oxychlorination and cracks it to VCM, recycling the HCl. In China, much capacity uses the acetylene (calcium carbide) route in coal-rich inland provinces, where coal and lime are burned with power in electric furnaces to make carbide, then acetylene, which reacts with HCl over mercuric chloride. A few plants buy EDC from the merchant market (US, Middle East, Japan exporters) and only crack it. Ethane-based direct routes have been piloted but not commercialised.
Routes compared
| Route | Share of supply | Inputs per tonne | Typical scale | Yield | Co-products | Unit cost |
|---|---|---|---|---|---|---|
| Balanced ethylene route (direct chlorination plus oxychlorination plus EDC cracking) | about 70% of world capacity (indicative) | about 0.47 t ethylene, 0.58 t chlorine, oxygen and fuel gas for cracking furnaces | 300-1,000 kt/yr VCM | about 95-98% on ethylene (indicative) | light and heavy chlorinated ends, burned with HCl recovery | about $500-550/t at $750/t ethylene and near-zero chlorine (indicative: 0.47 x $750 plus conversion) |
| Acetylene route from calcium carbide | about 30% of world capacity, most of it in China (indicative) | about 1.4-1.5 t calcium carbide (about 3.2-3.4 MWh per t carbide) and 0.58 t HCl per t VCM (indicative) | 300-1,000 kt/yr | high on acetylene | carbide slag (calcium hydroxide), about 1.5 t per t PVC (indicative) | competitive in coal regions; China's coal and power set the floor |
| Merchant EDC cracking | small | about 1.6 t EDC per t VCM (stoichiometric) | 100-400 kt/yr | high | HCl, about 0.58 t per t VCM | set by EDC import price |
How each route works
Balanced ethylene route (direct chlorination plus oxychlorination plus EDC cracking)Half the EDC comes from ethylene plus chlorine, half from ethylene plus HCl plus oxygen. Cracking EDC gives VCM and HCl, which goes back to oxychlorination, so the plant consumes no net HCl.
low cost where ethylene and power are cheap; integrated with chlor-alkali
Westlake 10-K FY2025 (integration); indicative Acetylene route from calcium carbideCoal coke and lime are smelted at about 2,000 C to calcium carbide; water releases acetylene, which reacts with HCl over a mercuric chloride on carbon catalyst. Plants sit beside coal mines and captive power in Inner Mongolia, Xinjiang, Shaanxi and Ningxia.
no oil or gas; very high CO2 and the world's largest industrial mercury use
S&P Global CEH VCM June 2025 (route dominance in China); indicative Merchant EDC crackingPlants without ethylene buy EDC by sea, crack it and use or sell the HCl. Egypt imported about 210,000 t/yr of EDC from Europe in 2023.
flexible; exposed to EDC price and needs an HCl outlet
Argus Chlor-Alkali Outlook Nov 2025 Unit economics are indicative ranges from the sources named; costs move with feedstock and energy prices, plant size and region.