Benzene from pyrolysis gasoline

Claim 2

A process in accordance with claim 1 wherein said hydrogenating total pressure is from about 300 to about 1, 000 p.s.i.g.; said reforming total pressure is from about 150 to about 700 p.s.i.g.; and said hydrodealkylating total pressure is from about 300 to about 1,000 p.s.i.g.

Claim 3

A process in accordance with claim 1 wherein said hydrogenating conditions includes a hydrogen to hydrocarbon mol ratio of about 1:1 to about 10:1; said reforming conditions includes a hydrogen to hydrocarbon mol ratio of about 1:1 to about 10:1; and said hydrodealkylating conditions includes a hydrogen to hydrocarbon mol ratio of about 3:1 to about 10:1.

Claim 4

A process in accordance with claim 1 wherein said hydrogenating temperature is from about 200* F. to about 600* F. and said hydrogenating total pressure is from about 400 to about 800 p.s.i.g.; said reforming temperature is from about 900* F. to about 1,000* F. and said reforming total pressure is from about 300 about 700 p.s.i.g.; and said hydrodealkylating temperature is from about 1,140* F. to about 1,350* F. and said hydrodealkylating total pressure is from about 350 to about 600 p.s.i.g.

Claim 5

A process in accordance with claim 1 which includes separating hydrogen sulfide formed in the hydrogenating step from the effluent of said hydrogenating step by contacting said effluent with a material selective for the removal of hydrogen sulfide.

Claim 6

A process in accordance with claim 1 which includes hydrogenating said effluent from a hydrodealkylating step under hydrogenating coNditions including a temperature of about 200* F. to about 700* F. in the presence of a hydrogenating catalyst to saturate olefins produced in said hydrodealkylation step.

Claim 7

A process for increasing the benzene yield from a hydrocarbon material comprising generally from about six to about 10 carbon atoms per molecule obtained as the byproduct from the pyrolysis cracking of hydrocarbons to produce primarily ethylene which comprises: hydrogenating said hydrocarbon material in the presence of hydrogen generated within said process under hydrogenating conditions including a hydrogenating temperature and a hydrogenation pressure in the presence of a hydrogenation catalyst to saturate olefinic hydrocarbons; reforming said hydrocarbon material under reforming conditions including a reforming temperature higher than said hydrogenating temperature and a reforming pressure lower than said hydrogenating pressure in the presence of a reforming catalyst to increase aromatic content of said hydrocarbon material and to produce hydrogen; hydrodealkylating said hydrocarbon material in the presence of hydrogen from said reforming step under hydrodealkylating conditions including a temperature higher than said reforming temperature and a pressure lower than said reforming pressure to hydrodealkylate aromatic compounds and also crack remaining nonaromatic hydrocarbons including those boiling close to benzene to obtain an effluent comprising benzene and hydrogen; recycling said hydrogen to said hydrogenation step; and recovering benzene from said effluent by distillation.

Claim 8

A process in accordance with claim 8 wherein said hydrogenating temperature is from about 125* F. to about 800* F.; said reform temperature is from about 850* F. to about 1,100* F.; and said hydrodealkylating temperature is from about 1,100* F. to about 1,400* F.

Claim 9

A process in accordance with claim 8 wherein said hydrogenating total pressure is from about 300 to about 1, 000 p.s.i.g.; said reforming total pressure is from about 150 to about 700 p.s.i.g.; and said hydrodealkylating total pressure is from about 300 to about 1,000 p.s.i.g.

Claim 10

A process in accordance with claim 8 wherein said hydrogenating condition includes a hydrogen to hydrocarbon mol ratio of about 1:1 to about 10:1; said reforming conditions includes a hydrogen to hydrocarbon mol ratio of about 1:1 to abut 10:1; and said hydrodealkylating conditions includes a hydrogen to hydrocarbon mol ratio of about 3:1 to about 10:1.

Claim 11

A process in accordance with claim 8 wherein said hydrogenating temperature is from about 200* F. to about 600* F. and said hydrogenating total pressure is from about 400 to about 800 p.s.i.g.; said reforming temperature is from about 900* F. to abut 1,000* F. and said reforming total pressure is from about 300 to about 700 p.s.i.g.; and said hydrodealkylating temperature is from about 1,140* F. to about 1,350* F. and said hydrodealkylating total pressure is from about 350 to about 600 p.s.i.g.

Claim 12

A process in accordance with claim 8 which includes separating hydrogen sulfide formed in the hydrogenating step from the effluent of said hydrogenating step by contacting said effluent with a material selective for the removal of hydrogen sulfide.

Claim 13

A process in accordance with claim 8 which includes hydrogenating said effluent from the hydrodealkylating step under hydrogenating conditions including a temperature of about 200* F. to about 700* F. in the presence of a hydrogenating catalyst to saturate olefins produced in said hydrodealkylation step.

Claim 14

A process for increasing the benzene yield from a hydrocarbon material comprising generally about six To 10 carbon atoms per molecule obtained from a byproduct of the pyrolysis cracking of hydrocarbon to produce primarily ethylene which comprises: hydrogenating said hydrocarbon material in the presence of hydrogen generated within said process under hydrogenating conditions including an average hydrogenating temperature of about 650* F. and a hydrogenating pressure of about 800 p.s.i.g. in the presence of a supported hydrogenating catalyst selected from the group consisting of metal from Group VI and the Iron Group metals from Group VIII of the Periodic table, their oxides and sulfides to saturate olefinic hydrocarbons; reforming aid hydrocarbon material under reforming conditions including an average reforming temperature of about 925* F. and a reforming pressure of about 500 p.s.i.g. in the presence of a reforming catalyst selected from the group consisting of metals from Group VI and metals from Group VIII of the Periodic table, their oxides and sulfides supported on a base to increase aromatic content of said hydrocarbon material and to produce hydrogen; hydrodealkylating said hydrocarbon material in the presence of hydrogen from said reforming step under hydrodealkylating conditions including an average temperature of about 1,250* F. and a pressure of about 450 p.s.i.g. to hydrodealkylate aromatic hydrocarbons and also crack remaining nonaromatic hydrocarbons including those boiling close to benzene to obtain an effluent comprising benzene and hydrogen; recycling said hydrogen to said hydrogenating step; and removing benzene from said effluent by distillation.

Claim 15

A process in accordance with claim 15 which includes separating hydrogen sulfide formed in the hydrogenating step from the effluent of said step by contacting said effluent with an adsorbent comprising zinc oxide.

Claim 16

A process in accordance with claim 15 which includes hydrogenating said effluent from the hydrodealkylating step under hydrogenating conditions including a temperature of about 200* F. to about 700* F. and in the presence of a hydrogenating catalyst selected from the group consisting of metals from Group VI and the Iron Group metals from Group VIII of the Periodic table, their oxides and sulfides supported on a base to saturate olefins produced in said hydrodealkylating step.