US3871993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Upgrading the octane value of naphtha employing a crystalline aluminosilicate zeolite which has a high silica to alumina ratio wherein alumina is incorporated in the interstices of the zeolite crystal
Abstract Treatment and conversion of low octane, low aromatics content naphthas to both a substantially higher octane C5 to 400*F fraction and a saturated LPG (C3 + C4 stream) product by relatively low temperature contact of such naphthas with a particular zeolite catalyst material in the absence of added hydrogen. The special catalyst comprises a zeolite having shape selectivity for monomethyl substituted paraffinic hydrocarbons, which has a high silica to alumina ratio of at least about 12, a constraint index of about 1 to 12, and a crystal density not substantially below about 1.6 grams per cubic centimeter and which, by reason of its composition, is eminently well suited to the upgrading of naphtha boiling range fractions by increasing the aromatics content thereof. This zeolite may have modifying metals, such as zinc, cadmium, etc., incorporated therewith in order to improve the aromatization activity thereof. The instant improvement comprises providing aluminum, out of the crystal latice of the zeolite, e.g., by exchange or impregnation and in addition to any which may be present in a matrixing component, along with the zeolite. It has been found that such aluminum significantly decreases the proportion of dry gas, C1 + C2, produced by this process.
IN THE PROCESS OF UPGRADING THE OCTANE VALUE OF NAPHTHA HAVING A CLEAR RESEARCH OCTANE NUMBER OF UP TO ABOUT 65 BY CONVERTING SUCH AT ELEVATED TEMPERATURE IN CONTACT WITH AN AROMATIZATION IMPROVING MODIFIED SYNTHETIC CRYSTALLINE ALUMINOSILICATE ZEOLITE HAVING A SILICA TO ALUMINA RATIO OF AT LEAST ABOUT 12, A CONSTRAINT INDEX OF ABOUT 1 TO 12, AND A CRYSTAL DENSITY OF NOT SUBSTANTIALLY LESS THAN ABOUT 1.6 GRAMS PER CUBIC CENTIMETER, THE IMPROVEMENT, WHEREBY INCREASING THE PRODUCTION OF SATURATED C3-C4 LPG WHILE MAINTAINING PRODUCTION OF HIGHER OCTANE GASOLINE HAVING A CLEAR RESEARCH OCTANE NUMBER OF AT LEAST ABOUT 85, WHICH COMPRISES CONTACTING SAID NAPHTHA WITH SAID ZEOLITE CATALYST HAVING ALUMINUM INCORPORATED INTO THE INTERSTICES OF THE ZEOLITE CRYSTAL ABOUT 600* TO 750*F IN THE ABSENCE OF ADDED HYDROGEN AT A SPACE VELOCITY OF UP TO ABOUT IS WHSV.
Claim 2
Dependent Claim
139 words
IN THE PROCESS OF UPGRADING THE OCTANE VALUE OF NAPHTHA HAVING A CLEAR RESEARCH OCTANE NUMBER OF UP TO ABOUT 65 BY CONVERTING SUCH AT ELEVATED TEMPERATURE IN CONTACT WITH AN AROMATIZATION IMPROVING MODIFIED SYNTHETIC CRYSTALLINE ALUMINOSILICATE ZEOLITE HAVING A SILICA TO ALUMINA RATIO OF AT LEAST ABOUT 12, A CONSTRAINT INDEX OF ABOUT 1 TO 12, AND A CRYSTAL DENSITY OF NOT SUBSTANTIALLY LESS THAN ABOUT 1.6 GRAMS PER CUBIC CENTIMETER, THE IMPROVEMENT, WHEREBY INCREASING THE PRODUCTION OF SATURATED C3-C4 LPG WHILE MAINTAINING PRODUCTION OF HIGHER OCTANE GASOLINE HAVING A CLEAR RESEARCH OCTANE NUMBER OF AT LEAST ABOUT 85, WHICH COMPRISES CONTACTING SAID NAPHTHA WITH SAID ZEOLITE CATALYST HAVING ALUMINUM INCORPORATED INTO THE INTERSTICES OF THE ZEOLITE CRYSTAL ABOUT 600* TO 750*F IN THE ABSENCE OF ADDED HYDROGEN AT A SPACE VELOCITY OF UP TO ABOUT IS WHSV.
Claim 3
Dependent Claim
12 words
The improved process claimed in claim 1 wherein said zeolite is ZSM-5.
Claim 4
Dependent Claim
21 words
The improved process claimed in claim 1 wherein said aluminum is incorporated in proportions of up to about 10 weight percent.
Claim 5
Dependent Claim
28 words
The improved process claimed in claim 1 including zinc in addition to aluminum both being present in a cumulative proportion of about 0.5 to 7 percent by weight.
Claim 6
Dependent Claim
18 words
The improved process claimed in claim 1 wherein said catalyst is ZSM-5 having zinc and aluminum exchanged thereinto.
Claim 7
Dependent Claim
22 words
The improved process claimed in claim 1 wherein said modified zeolite has a silica to alumina ratio of up to about 70.
Claim 8
Dependent Claim
14 words
The improved process claimed in claim 1 wherein said aluminum is incorporated during calcining.