Improved zeolite L catalyst for reforming

Claim 2

A catalyst for hydrocarbon reforming comprising zeolite L having exchangeable cations of which at least 90% are metal ions selected from sodium, barium, lithium, potassium, rubidium and cesium and containing at least one metal from Group VIII of the periodic table of elements and having a dehydrocyclizing effect, the zeolite L being loaded with the Group VIII metal and subsequently calcined characterized in that prior to the calcining the zeolite L is soaked in an alkali solution having a pH of at least 11 for a time and at a temperature effective to increase the period of time over which the catalytic activity of the catalyst is maintained under reforming conditions.

Claim 3

The catalyst of claim 1, wherein the alkali soak is carried out to preferentially remove silica from the type L zeolite without substantial loss of crystallinity.

Claim 4

The catalyst of claim 2, wherein 0.1 to 15% by weight of the silica is removed from said zeolite.

Claim 5

The catalyst of any of claims 1 to 3, wherein the alkali soak is effective to increase by at least 50 hours the time period over which catalytic activity is maintained, based on a standardized test utilizing a hydrocarbon feedstock containing 60 weight percent hexane, 30 weight percent 3-methylpentane and 10 weight percent methylcyclopentane and on reforming conditions of about 500°C, 690 KPa, space velocity of 2.5 W/W/HR and an H 2/ oil mole ratio of 6.

Claim 6

The catalyst of any of claims 1 to 3, wherein the alkali soak is effective to increase the time to at least 250 hours over which the catalytic activity of the catalyst is maintained at a level of at least a 40 weight percent conversion to aromatics, based on a standardized test utilizing a hydrocarbon feedstock containing 60 weight percent hexane, 30 weight percent 3-methylpentane and 10 weight percent methylcyclopentane and on reforming conditions of about 500 * C, 690 KPa, space velocity of 2.5 W/W/HR and an H 2/ oil mole ratio of 6.

Claim 7

The catalyst of claim 5, wherein the alkali soak is effective to maintain catalytic activity'for at least 300 hours in the standardized test.

Claim 8

The catalyst of any of claims 1 to 6, wherein the alkali solution comprises an alkali having a cation chosen from sodium, potassium, rubidium, cesium, strontium, barium and mixtures thereof, and an anion chosen from hydroxide, carbonate, phosphate, borate and mixtures thereof.

Claim 9

The catalyst of claim 7, wherein the alkali is potassium hydroxide, cesium hydroxide or rubidium hydroxide.

Claim 10

The catalyst of any of claims 1 to 8, wherein the alkali solution is an aqueous solution.

Claim 11

the catalyst of any of claims 1 to 9, wherein the soaking is carried out under agitation the pH of the alkali solution is 13 to 16, the temperature of soaking is from 25 to 120°C and the soaking time is from 5 to 80 hours.

Claim 12

The catalyst of any of claims 1 to 10, in which the soaked zeolite is washed to remove excess alkali and dried.

Claim 13

The catalyst of any of claims 1 to 11, wherein the zeolite L contains at least one alkali metal selected from potassium, rubidium and cesium and contains from 0.1 to 6.0% by weight of at least one dehydrocyclizing metal selected from platinum, palladium and iridium.

Claim 14

The catalyst of claim 12, wherein the zeolite L contains potassium and 0.2 to 5% by weight of platinum.

Claim 15

The catalyst of any of claims 1 to 13, wherein the zeolite additionally contains at least one metal chosen from rhenium, tin and germanium.

Claim 16

The catalyst of any of claims 1 to 14, wherein the zeolite catalyst also contains sulphur.

Claim 17

The catalyst of any of claims 1 to 15, wherein the zeolite L is charged with the dehydrocyclizing metal after the alkali soak.

Claim 18

The catalyst of any of claims 1 to 16 in which the soaked zeolite is subsequently shaped.

Claim 19

Zeolite L suitable for use as a catalyst support characterized in that the zeolite L is soaked in an alkali solution having a pH of at least 11 for a temperature and a period of time effective to increase the period of time over which the catalytic activity is maintained when said zeolite is loaded with a catalytically active metal said soaking carrried out prior to calcining the zeolite when it is loaded with a dehydrocyclizing metal.

Claim 20

Zeolite L suitable for use as a catalyst support characterized in that the zeolite L is soaked in an alkali solution having a pH of at least 11 for a temperature and a period of time effective to increase the period of time over which the catalytic activity is maintained when said zeolite is loaded with a catalytically active metal said soaking carrried out prior to calcining the zeolite when it is loaded with a dehydrocyclizing metal.

Claim 21

Zeolite of claim 19 wherein 0.05 to 30 weight percent of the silica is removed from said zeolite.

Claim 22

Zeolite of claims 18 or 19, wherein the soaking is carried out under agitation, the pH of the alkali solution is 13 to 16, the temperature of soaking is between 25 and 120°C and the soaking time is between 5 and 80 hours.

Claim 23

A reforming process for producing aromatic hydrocarbons from a hydrocarbon feedstock containing paraffins of at least C 6 comprising: contacting the hydrocarbon feedstock in the presence of hydrogen at elevated temperatures with a catalyst which comprises zeolite L having exchangeable cations of which at least 90% are alkali metal ions selected from the group consisting of sodium, lithium, potassium, rubidium, barium and cesium and containing at least one metal selected from the group consisting of Group VIII of the periodic table of elements and having a dehydrocyclizing effect characterized in that the zeolite L is soaked prior to calcining the dehydrocyclizing metal loaded zeolite L, in an alkali solution having a pH of at least 11 for a time and at a temperature effective to increase the period of time over which the catalytic activity of the catalyst is maintained under reforming conditions.

Claim 24

A reforming process for producing aromatic hydrocarbons from a hydrocarbon feedstock containing paraffins of at least C 6 comprising: contacting the hydrocarbon feedstock in the presence of hydrogen at elevated temperatures with a catalyst which comprises zeolite L having exchangeable cations of which at least 90% are alkali metal ions selected from the group consisting of sodium, lithium, potassium, rubidium, barium and cesium and containing at least one metal selected from the group consisting of Group VIII of the periodic table of elements and having a dehydrocyclizing effect characterized in that the zeolite L is soaked prior to calcining the dehydrocyclizing metal loaded zeolite L, in an alkali solution having a pH of at least 11 for a time and at a temperature effective to increase the period of time over which the catalytic activity of the catalyst is maintained under reforming conditions.

Claim 25

The process of claim 21, wherein the catalyst is as claimed in any of claims 1 to 17.

Claim 26

The process of claim 21 or claim 22, wherein the reforming conditions comprise a temperature of 450 to 520°C; pressure of 517KPa to 1.2 MPa; hourly liquid space velocity of 1 to 10 W/W/HR; and H 2/ oil mole ratio of 4 to 10.