Process for producing high purity benzene

Claim 1

A PROCESS FOR PRODUCING HIGH PURITY BENZENE WHICH COMPRISES: (A) AS FIRST PROCESS STEP, CONTACTING THE 60-200*C. FRACTION OF CRACKED OILS, WHICH ARE THE BY-PRODUCT IN THE PRODUCTION OF GASEOUS OLEFINS BY STEAM CRACKING PETROLEUM HYDROCARBONS, WITH HYDROGEN IN A MOLAR PROPORTION OF CRACKED OIL FRACTION:HYDROGEN OF 1:0.2 TO 2.00 AT A TEMPERATURE FROM AMBIENT TEMPERATURE TO 250*C. AND A PRESSURE OF AT LEAST 10 KG./CM.2 IN THE PRESENCE OF HYDROGENATION CATALYST, TO CONVERT THE DIOLEFINS CONTAINED IN SAID FRACTION TO MONO-OLEFINS AND/OR PARAFFIN HYDROCARBONS; (B) AS SECOND PROCESS STEP, CONTACTING THE OIL OBTAINED IN STEP (A) WITH HYDROGEN IN A MOLAR PROPORTION OF OIL:HYDROGEN OF 1:2 TO 10 AT A TEMPERATURE OF 500* TO 800*C. AND A PRESURE OF AT LEAST 10 KG./CM.2 IN THE ABSENCE OF SOLID DEALKYLATION CATALYST, TO HYDROCRACK MONO-OLEFINS AND/OR PARAFFIN HYDROCARBONS AS WELL AS TO DEALKYLATE ALKYL-SUBSTITUTED AROMATIC HYDROCARBONS CONTAINED IN SAID LAST-NAMED OIL, AND (C) AS THIRD PROCESS STEP, HEATING THE RESULTANT PRODUCT OF THE SECOND STEP OF 150* TO 200*C. IN THE PRESENCE OF HYDRODESULFURATION CATALYST TO DECOMPOSE AND REMOVE SULFUR COMPOUNDS CONTAINED IN SAID PRODUCT, AND (D) THEREAFTER SEPARATING BENZENE FROMTHE RESULTANT LIQUID PRODUCT OF THE THIRD STEP.