Reforming process

Abstract

Abstract A C5+ NAPHTHA CONTAINING C6 THROUGH C10 AND EVEN C11 AND C12 NAPHTHENES AND LINEAR (NON-RING STRUCTURE) PARAFFINS IS REFORMED TO IMPROVE ITS OCTANE VALUE BY PASSAGE THROUGH ONE OR A PLURALITY OF RELATIVELY HIGH PRESSURE ACIDIC PLATINUM CATALYST NAPHTHENE AROMATIZATION REACTORS IN SERIES WITH ONE OR MORE RELATIVELY LOWER PRESSURE PARAFFIN DEHYDROCYCLIZATION CATALYST REACTORS. MOST C9 AND C10 LINEAR PARAFFINS HAVE AN EXTREMELY LOW OCTANE VALUE (THE OCTANE NUMBER OF NORMAL DECANE IS - 53) AND MUST GENERALLY BE CRACKED TO HIGHER OCTANE NUMBER FRAGMENTS OR TO GASES TO ACHIEVE A GASOLINE PRODUCT OF SATISFACTORY OCTANE NUMBER. IN THE PRIOR ART THIS CRACKING GENERALLY OCCURRED IN THE ACIDIC PLATINUM CATALYST PHASE WHEREIN THE HYDROGEN PRESSURE IS HIGH, PROTECTING THE CATALYST FROM EXCESSIVE COKING. CRACKING OF THE C9 AND C10 PARAFFINS IN THE DEHYDROCYCLIZATION PHASE WHEREIN THE TOTAL PRESSURE IS LOWER IN ORDER TO FAVOR DEHYDROCYCLIZATION IN ADDITION TO DEHYDROGENATION WOULD RESULT IN SEVERE COKING OF CATALYST. ACCORDING TO THIS INVENTION C9 AND C10 LINEAR PARAFFINS ARE NOT HYDROCRACKED BUT RATHER ARE DEHYDROCYCLIZED. IT HAS NOW BEEN DISCOVERED THAT THE DEHYDROCYCLIZATION PHASE MUST DEHYDROCYCLIZE C9 AND C10 PARAFINS TO C9 AND C10 AROMATICS IF THERE IS TO BE AN INCREASE IN OCTANE-BARREL VALUE IN THE DEHYDROCYCLIZATION PHASE. ACCORDING TO THE PRESENT PROCESS, THE C9 AND C10 PARAFFINS ARE NOT CRACKED IN THE HIGH PRESSURE PASE BUT ARE CHARGED TO THE LOW PRESSURE DEHYDROCYCLIZATION CATALYST PHASE WHEREIN THE PRESSURE IS SUFFICIENTL Y LOW TO DEHYDROCYCLIZATION THE C9 AND C10 PARAFFINS SO THAT THERE IS A NET INCREASE IN C9 AND C10 AROMATICS IN THE DEHYDROCYCLIZATION PHASE. THE PRESSURE IN THE DEHYDROCYCLIZATION PHASE IS SUFFICIENTLY LOW THAT THERE IS RELATIVELY LITTLE OR NO NET INCREASE IN C6 AND C7 AROMATICS AT LEAST IN THE ZONE OF THE DEHYDROCYCLIZATION PHASE WHEREIN DEHYDROAROMATIZATION OF C9 AND C10 PARAFFINS OCCURS. IT HAS NOW BEEN DISCOVERED THAT A SIGNIFICANT NET INCREASE OF C9 AND C10 AROMATICS IS INCOMPATIBLE WITH A SIGNIFICANT NET INCREASE IN C6 AND C7 AROMATICS IN THE SAME DEHYDROCYCLIZATION ZONE, AND VICE VERSA. IT HAS FURTHER BEEN DISDISCOVERED THAT DEHYDROCYCLIZATION OF C9 AND C10 LINEAR PARAFFINS IS ENHANCED BY THE PRESENCE IN THE FEED OF C9 AND C10 AROMATICS CONTAINING MULTI-METHYL OR ETHYL GROUPS ON THE BENZENE RING TOGETHER WITH A HIGH RATIO OF HYDROGEN TO HYDROCARBON, EVEN THOUGH BOTH AROMATICS AND HYDROGEN ARE PRODUCTS OF THE REACTION. THEREFORE, A VARIATION IN THE PROCESS ACCOMPLISHES DEHYDROCYCLIZATION OF C6 AND C7 LINEAR PARAFFINS IN AN UPSTREAM ZONE OF THE DEHYDROCYCLIZA TION PHASE AND UTILIZES THE HYDROGEN AND AROMATICS THEREIN PRODUCED WITH OR WITHOUT HYDROGEN AND AROMATICS PRODUCED IN THE HIGH PRESSURE NAPHTHENE AROMATIZATION PHASE TO ENHANCE DEHYDROCYCLIZATION OF C9 AND C10 PARAFFINS WHICH ARE SEPARATELY ADDED TO A DOWNSTREAM ZONE IN THE DEHYDROCYCLIZATION PHASE.

Inventors

• 👤 D Ko
• 👤 D Stahlfeld

Bibliographic Details