Method for quenching a gas stream in the production of vinyl chloride monomer

A method of quenching a gas stream comprising vinyl chloride, hydrogen chloride, and unreacted 1,2-dichloroethane produced by the pyrolysis of 1,2-dichloroethane and containing undesired byproducts of pyrolysis, comprising the steps of:

• (a) providing a quench column, having an upper and a lower end, the lower end of the quench column containing a quantity of quench liquid;
• (b) introducing the gas stream directly into the quench liquid to cool the gas stream to cease the pyrolysis of the 1,2-dichloroethane and minimize the formation of additional byproducts whereby 1,2-dichloroethane, vinyl chloride, and hydrogen chloride vapors rise from the quench liquid;
• (c) providing a plurality of column fractional distillation trays, with at least an upper column fractional distillation tray and a bottom column fractional distillation tray, within the quench column above the quantity of quench liquid;
• (d) passing the 1,2-dichloroethane, vinyl chloride, and hydrogen chloride vapors upwardly through the plurality of column fractional distillation trays;
• (e) introducing liquid 1,2-dichloroethane, vinyl chloride, and hydrogen chloride into the upper end of the quench column, above the plurality of column fractional distillation trays;
• (f) removing 1,2-dichloroethane, vinyl chloride, and hydrogen chloride vapors from the upper end of the quench column;
• and
• (g) removing a liquid stream of 1,2-dichloroethane, vinyl chloride, and hydrogen chloride from the bottom column fractional distillation tray.