| 摘要 |
<p>Hydrocarbon reforming/dehydrocyclisation process and an improved catalyst (I) for use in the process are claimed. (I) comprising a zeolite L (with at least 90 percent of its exchangeable cations being Na, Ba, Li, K, Rb and Cs) loaded with 0.1-6 (pref. 0.2-5) wt.percent of at least a Gp.VIII dehydrocyclising metal and opt. Re, Sn and/or Ge and subsequently calcined, the improvement comprising subjecting the catalyst, prior to the calcining, to an alkali soak in a soln. having a pH of over 11 to preferentially remove 0.05-30 (pref. 0.1-15) wt. percent SiO2 from the zeolite without substantial loss of crystallinity. - (I) is used to convert 6-10C paraffins to aromatics (see US 4104320) and inclusion of the alkali soak increases the time over which catalytic activity is maintained. (0/1) EPAB- EP-107389 B 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 to increase the period of time over which the catalytic activity of the catalyst is maintained under reforming conditions, prior to the calcining the zeolite L is soaked in an alkali solution having a pH of at least 11 for a time and a temperature 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 deg.C, 690 KPa, space velocity of 2.5 W/W/HR and an H2/oil mole ratio of 6. - (12pp) - EP-107389 B 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 to increase the period of time over which the catalytic activity of the catalyst is maintained under reforming conditions, prior to the calcining the zeolite L is soaked in an alkali solution having a pH of at least 11 for a time and a temperature 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 deg.C, 690 KPa, space velocity of 2.5 W/W/HR and an H2/oil mole ratio of 6. (12pp) USAB- US4448891 A Catalyst for hydrocarbon reforming comprises a zeolite with exchangeable cations at least 90% of which are selected with at least one group 8 metal. The zeolite has a dehydrocyclising effect and is produced by soaking type L zeolite in an alkaline (pH at least 11) for sufficient time and at a sufficient temperature that the catalytic activity is maintained under reforming conditions. The pretreated zeolite is then calcined in its metal loaded form. - Typically the treatment extends the service life of the catalyst from 50-150 to at least 250 hrs. - (7pp) - US4478706 A Aromatic hydrocarbons are produced from a hydrocarbon feedstock (I) contg. at least 6C paraffins in a reforming process, by contacting (I) plus added H2 at elevated temps. with a catalyst comprising a zeolite having exchangeable cations of which at least 90% are Na, Li, K, Rb, Ba or Cs ions and contg. at least one Gp. VIII metal and having a dehydrocyclising effect. The zeolite is produced by soaking a type L zeolite prior to calcining the dehydrocyclising metal loaded zeolite in an alkali soln. having pH of at least 11 for a time and at a temp. effective to increase the time over which the catalytic activity of the catalyst is held under reforming conditions. - Pref. the alkali soak is effect to preferentially remove silica (pref. 0.1-15 wt.%) from the zeolite without substantial loss of crystallinity.</p> |
