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.

Provided is a continuous process for converting waste plastic into recycle for polypropylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and 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. Pyrolysis oil and wax, comprising naphtha/diesel and heavy fractions, is passed to a refinery FCC unit. A liquid petroleum gas C.sub.3 olefin/paraffin mixture is recovered from the FCC unit. The C.sub.3 paraffins and C.sub.3 olefins are separated into different fractions with the C.sub.3 olefin fraction passed to a propylene polymerization reactor, and the C.sub.3 paraffin fraction passed optionally to a dehydrogenation unit to produce additional propylene.

Provided is a continuous process for converting waste plastic into recycle for polypropylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and 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. Pyrolysis oil and wax, comprising naphtha/diesel and heavy fractions, is passed to a refinery FCC unit. A liquid petroleum gas C.sub.3 olefin/paraffin mixture is recovered from the FCC unit. The C.sub.3 paraffins and C.sub.3 olefins are separated into different fractions with the C.sub.3 olefin fraction passed to a propylene polymerization reactor, and the C.sub.3 paraffin fraction passed optionally to a dehydrogenation unit to produce additional propylene.

An H.sub.2-rich fuel gas stream can be advantageously produced by reforming a hydrocarbon/steam mixture in to produce a reformed stream, followed by cooling the reformed stream in a waste-heat recovery unit to produce a high-pressure steam stream, shifting the cooled reformed stream a first shifted stream, cooling the first shifted stream, shifting the cooled first shifted stream to produce a second shifted stream, cooling the second shifted stream, abating water from the cooled second shifted stream to obtain a crude gas mixture stream comprising H.sub.2 and CO.sub.2, and recovering a CO.sub.2 stream from the crude gas mixture stream. The H.sub.2-rich stream can be advantageously combusted to provide thermal energy needed for residential, office, and/or industrial applications including in the H.sub.2-rich fuel gas production process. The H.sub.2-rich fuel gas production process can be advantageously integrated with an olefins production plant comprising a steam cracker.

A process to produce 1-octene and 1-decene includes (a) separating a composition containing an oligomer product—which contains from 15 to 80 mol % C.sub.6 olefins, from 20 to 80 mol % C.sub.8 olefins, and from 5 to 20 mol % C.sub.10+ olefins—into a first oligomer composition containing C.sub.6 alkanes and at least 85 mol % C.sub.6 olefins (e.g., 1-hexene), a second oligomer composition containing at least 85 mol % C.sub.8 olefins (e.g., 1-octene), and a heavies stream containing C.sub.10+ olefins, then (b) contacting a metathesis catalyst system with the first oligomer composition to form a first composition comprising C.sub.10 linear internal olefins, (c) contacting the C.sub.10 linear internal olefins with an isomerization hydrofunctionalization catalyst system to form a second composition containing a functionalized alkane, (d) retro-hydrofunctionalizing the functionalized alkane to form a third composition containing 1-decene, and (e) purifying the third composition to isolate a fourth composition containing at least 90 mol % 1-decene. Processes to produce 1-hexene and 1-decene also are described, as well as related manufacturing systems.

A process to produce 1-octene and 1-decene includes (a) separating a composition containing an oligomer product—which contains from 15 to 80 mol % C.sub.6 olefins, from 20 to 80 mol % C.sub.8 olefins, and from 5 to 20 mol % C.sub.10+ olefins—into a first oligomer composition containing C.sub.6 alkanes and at least 85 mol % C.sub.6 olefins (e.g., 1-hexene), a second oligomer composition containing at least 85 mol % C.sub.8 olefins (e.g., 1-octene), and a heavies stream containing C.sub.10+ olefins, then (b) contacting a metathesis catalyst system with the first oligomer composition to form a first composition comprising C.sub.10 linear internal olefins, (c) contacting the C.sub.10 linear internal olefins with an isomerization hydrofunctionalization catalyst system to form a second composition containing a functionalized alkane, (d) retro-hydrofunctionalizing the functionalized alkane to form a third composition containing 1-decene, and (e) purifying the third composition to isolate a fourth composition containing at least 90 mol % 1-decene. Processes to produce 1-hexene and 1-decene also are described, as well as related manufacturing systems.

A process (100, 200, 300) for the production of ethylene is proposed in which a first feed gas (A) and a second feed gas (B) are fed to a reactor (1) and processed therein by vapour cracking to obtain a product mixture (C), the first feed gas (A) comprising more than 90 weight percent saturated hydrocarbons and more than 80 weight percent ethane, and wherein the product mixture (C) or a part thereof is subjected to a treatment (2, 3, 4) and the resulting mixture (F) or a part thereof is subjected to a separation (10) to obtain a resulting mixture (F) containing hydrogen, methane, ethane, ethylene and hydrocarbons having three, four and at least five carbon atoms. The separation (10) being provided in that it comprises an ethylene separation step (7) to which at least the ethane, the ethylene and the hydrocarbons having three carbon atoms from the succeeding mixture (F) or a part thereof are fed unseparated from each other in a common separation insert (S, V, X), in which in the ethylene separation step (7) a light fraction (K) containing more than 95 mole percent ethylene is fed, and a heavy fraction (T, W, Y) containing at least a portion of the ethane from the separation insert (S, V, X) and at least 15% by weight of the hydrocarbons having three and four carbon atoms from the separation insert (S, V, X), and wherein the heavy separation product (T, W, Y) from the ethylene separation step (7) or a portion thereof is used as part or to form the second feed gas (B). A corresponding annex is also the subject of this invention.

A process (100, 200, 300) for the production of ethylene is proposed in which a first feed gas (A) and a second feed gas (B) are fed to a reactor (1) and processed therein by vapour cracking to obtain a product mixture (C), the first feed gas (A) comprising more than 90 weight percent saturated hydrocarbons and more than 80 weight percent ethane, and wherein the product mixture (C) or a part thereof is subjected to a treatment (2, 3, 4) and the resulting mixture (F) or a part thereof is subjected to a separation (10) to obtain a resulting mixture (F) containing hydrogen, methane, ethane, ethylene and hydrocarbons having three, four and at least five carbon atoms. The separation (10) being provided in that it comprises an ethylene separation step (7) to which at least the ethane, the ethylene and the hydrocarbons having three carbon atoms from the succeeding mixture (F) or a part thereof are fed unseparated from each other in a common separation insert (S, V, X), in which in the ethylene separation step (7) a light fraction (K) containing more than 95 mole percent ethylene is fed, and a heavy fraction (T, W, Y) containing at least a portion of the ethane from the separation insert (S, V, X) and at least 15% by weight of the hydrocarbons having three and four carbon atoms from the separation insert (S, V, X), and wherein the heavy separation product (T, W, Y) from the ethylene separation step (7) or a portion thereof is used as part or to form the second feed gas (B). A corresponding annex is also the subject of this invention.

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.