Using spent caustic solution from pygas treatment to neutralize halogens from liquified waste plastic
AssigneeEastman Chemical Company
InventorsMichael Gary Polasek, Daryl Bitting, Xianchun Wu, David Eugene Slivensky
Life of this patent
Estimating the term…
Abstract
Processes and facilities for producing recycled chemical products from waste plastic are described herein. The processes include treating process streams, such as a pyrolysis gas stream and/or at least a portion of a cracker furnace effluent stream, in a caustic scrubber process to remove certain components, such as carbon dioxide. The spent caustic solution from the caustic scrubber process is then recycled and reused in other caustic processes within the facility, which can include a halogen neutralization process from removing halogens from a liquification process off-gas.
Claims14
A chemical recycling process comprising:
- (a) introducing a solid waste plastic into a liquefaction process and producing a liquified waste plastic and a halogen-enriched gaseous material;
- (b) pyrolyzing at least a portion of the liquified waste plastic to thereby produce a pyrolysis effluent comprising a pyrolysis gas (pygas) and a pyrolysis oil (pyoil);
- (c) separating at least a portion of the pyrolysis effluent to produce a pygas stream and a pyoil stream;
- (d) introducing at least a portion of the pygas stream into a first caustic scrubber process and producing at least a carbon dioxide (CO2) and/or sulfur-depleted scrubber effluent stream and a spent caustic stream;
- and
- (e) scrubbing at least a portion of the halogen-enriched gaseous material in a second caustic scrubber process using at least a portion of the spent caustic stream to thereby produce a halogen-depleted gas stream and a wastewater stream.
A chemical recycling process comprising:
- (a) introducing a solid waste plastic into a liquefaction process and producing a liquified waste plastic and a halogen-enriched gaseous material;
- (b) introducing a feedstock comprising at least a portion of a cracker furnace effluent into a first caustic scrubber process and thereby producing at least a carbon dioxide (CO2) and/or sulfur-depleted effluent stream and a spent caustic stream;
- and
- (c) scrubbing at least a portion of the halogen-enriched gaseous material in a second caustic scrubber process using at least a portion of the spent caustic stream to thereby produce a halogen-depleted gas stream and a wastewater stream.
Dependencies are inferred from the claim text.