EDC pyrolysis furnace: 1,2-dichloroethane to vinyl chloride monomer

The balanced-process route to PVC's monomer: 1,2-dichloroethane (EDC) thermally cracks in a fired furnace to vinyl chloride (VCM) + HCl (C2H4Cl2 -> C2H3Cl + HCl, exactly mass-balanced), the HCl is stripped overhead in a distillation column (recovered pure -- it's recycled to the plant's oxychlorination unit in a real balanced VCM process, not modeled here), and a second column separates VCM product from unconverted EDC (also recycled in a real plant). Unlike Linde's proprietary furnace internals (tube metallurgy, coking-cycle length, radiant-zone geometry), EDC pyrolysis chemistry itself is standard, widely published petrochemical engineering (Kirk-Othmer and equivalent references), not proprietary Linde IP -- so this is built directly from the real reaction and typical single-pass conversion (~50-55%, a widely cited industrial range for this process, not a specific plant's exact figure), the same 'illustrative, representative, not literature-pinned to one source' posture used throughout this codebase's cracking-furnace examples. Honesty note: a real EDC/VCM plant recycles both the HCl (to oxychlorination) and unconverted EDC (back to the furnace); both leave as standalone product streams here since neither the oxychlorination unit nor a recycle loop is modeled in this example.