Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization or for normal alpha olefins. The process comprises selecting waste plastics containing polyethylene and/or polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a crude unit in a refinery from which is recovered a straight run naphtha fraction (C.sub.5-C.sub.8) or a propane/butane (C.sub.3-C.sub.4) fraction. The straight run naphtha fraction, or propane and butane (C.sub.3-C.sub.4) fraction, is passed to a steam cracker for ethylene production. The ethylene is converted to normal alpha olefin and/or polyethylene. Also, a heavy fraction from the pyrolysis reactor can be combined with a heavy fraction of normal alpha olefin stream recovered from the steam cracker. The combined heavy fraction and heavy fraction of normal alpha olefin stream can be passed to a wax hydrogenation zone to produce wax.

Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization or for normal alpha olefins. The process comprises selecting waste plastics containing polyethylene and/or polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a crude unit in a refinery from which is recovered a straight run naphtha fraction (C.sub.5-C.sub.8) or a propane/butane (C.sub.3-C.sub.4) fraction. The straight run naphtha fraction, or propane and butane (C.sub.3-C.sub.4) fraction, is passed to a steam cracker for ethylene production. The ethylene is converted to normal alpha olefin and/or polyethylene. Also, a heavy fraction from the pyrolysis reactor can be combined with a heavy fraction of normal alpha olefin stream recovered from the steam cracker. The combined heavy fraction and heavy fraction of normal alpha olefin stream can be passed to a wax hydrogenation zone to produce wax.

Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization or for normal alpha olefins. The process comprises selecting waste plastics containing polyethylene and/or polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a crude unit in a refinery from which is recovered a straight run naphtha fraction (C.sub.5-C.sub.8) or a propane/butane (C.sub.3-C.sub.4) fraction. The straight run naphtha fraction, or propane and butane (C.sub.3-C.sub.4) fraction, is passed to a steam cracker for ethylene production. The ethylene is converted to normal alpha olefin and/or polyethylene. Also, a heavy fraction from the pyrolysis reactor can be combined with a heavy fraction of normal alpha olefin stream recovered from the steam cracker. The combined heavy fraction and heavy fraction of normal alpha olefin stream can be passed to a wax hydrogenation zone to produce wax.

A continuous process for converting waste plastic into recycle for polypropylene polymerization is provided. The process integrates refinery operations to provide an effective and efficient recycle process. The process comprises selecting waste plastics containing polyethylene and polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a refinery FCC unit, from which is recovered a liquid petroleum gas C.sub.3 olefin/paraffin mixture. The C.sub.3 paraffins and C.sub.3 olefins are separated into different fractions with a propane/propylene splitter. The C.sub.3 olefin fraction is passed to a propylene polymerization reactor. The C.sub.3 paraffin fraction is optionally passed to a dehydrogenation unit to produce additional propylene and then the resulting C.sub.3 olefin is passed to a propylene polymerization reactor. The heavy fraction of pyrolyzed oil is passed to an isomerization dewaxing unit to produce a lubricating base oil.

A continuous process for converting waste plastic into recycle for polypropylene polymerization is provided. The process integrates refinery operations to provide an effective and efficient recycle process. The process comprises selecting waste plastics containing polyethylene and polypropylene and then passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a refinery FCC unit, from which is recovered a liquid petroleum gas C.sub.3 olefin/paraffin mixture. The C.sub.3 paraffins and C.sub.3 olefins are separated into different fractions with a propane/propylene splitter. The C.sub.3 olefin fraction is passed to a propylene polymerization reactor. The C.sub.3 paraffin fraction is optionally passed to a dehydrogenation unit to produce additional propylene and then the resulting C.sub.3 olefin is passed to a propylene polymerization reactor. The heavy fraction of pyrolyzed oil is passed to an isomerization dewaxing unit to produce a lubricating base oil.

A process for the treatment of a light naphtha feedstock that comprises normal paraffins and iso-paraffins may include separating the feedstock into a first iso-paraffin stream and a normal paraffin stream. The separating may be performed with 5A molecular sieves, a pressure of about 1-3 bars, and a temperature of 100-260° C. A product stream may be provided by subjecting the normal paraffin stream to at least one of steam cracking, isomerizing, and aromatizing.

A process for the treatment of a light naphtha feedstock that comprises normal paraffins and iso-paraffins may include separating the feedstock into a first iso-paraffin stream and a normal paraffin stream. The separating may be performed with 5A molecular sieves, a pressure of about 1-3 bars, and a temperature of 100-260° C. A product stream may be provided by subjecting the normal paraffin stream to at least one of steam cracking, isomerizing, and aromatizing.

Systems and processes disclosed may be used to produce a high purity isobutane stream and a high purity 1-butene stream from mixed C4 streams having disparate starting compositions.

Systems and processes disclosed may be used to produce a high purity isobutane stream and a high purity 1-butene stream from mixed C4 streams having disparate starting compositions.

A method for selectively hydrogenating acetylene in a cracked gas from a steam cracking unit for producing olefins may include separating a hydrogenation feed from the cracked gas. The hydrogenation feed may include acetylene, hydrogen, carbon monoxide, and at least one product. The method may further include contacting the hydrogenation feed with an acetylene hydrogenation catalyst, the contacting causing hydrogenation of at least a portion of the acetylene of the hydrogenation feed to produce a hydrogenation effluent. In response to a change in a composition of a feedstock to the steam cracking unit that results in a change in a hydrogen concentration in the hydrogenation feed, the method may further include determining the hydrogen concentration in the hydrogenation feed and increasing or decreasing a temperature of the hydrogenation feed based on the determined hydrogen concentration of the hydrogenation feed.