Recovery of high purity hydrogen chloride from PVC waste

摘要

Process for the disposal of PVC opt. contg. other (in)organic components and/or other plastics, by recovering energy and / or recycling solid, liq. or gaseous by-prods., pref. pure and / or purified hydrogen chloride, comprises : (1) incinerating or gasifying low chlorine content PVC and recovering the thermal energy; (2) pyrolysing high chlorine content PVC at 200 - 750 deg C and 0.1 - 120 bar whilst adding more than 0.25 mass % chlorine-contg. waste prods. that are unstable under the reaction conditions as low temp. accelerators; (3) partially condensing the gas mixt. at -40 deg C up to the selected reaction temp. and 0.1 - 120 bar, and recycling the condensate by known techniques; (4) separating the gas mixt. using a HCl-selective polymer membrane; (5) removing the by-prods. remaining in the HCl-rich fraction by sorption; (6) returning some of the purified gas to the pyrolysis reactor and adding it in an amt. greater than 0.25 vol.% (w.r.t. pyrolysis gas); and (7) recovering thermal energy produced when the gaseous and solid residues are burnt in gasifiers or incineration ovens, and recycling the hydrogen chloride.