JP2788348B

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurisation followed by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5. The treatment over the acidic catalyst in the second step restores the octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product with an octane number comparable to that of the feed naphtha. A catalytically cracked naphtha from the FCC main column (10) is first hydrotreated in a hydrotreater (11) which it enters through inlet (12). From hydrotreater (11), the desulfurised naphtha passes through line (13) to the second reactor (14) in which it is contacted with ZSM-5 or another acidic catalyst, for example zeolite beta or MCM-22 where a controlled degree of cracking takes place with an octane, which was lost in the hydrotreater, being restored. The effluents from reactor (14) are separated and further processed.