Selective production of n-paraffin hydrocracking products from heavier n-paraffins
A process for selectively making hydrocracked n-paraffins from hydrocarbon compositions comprising heavy n-paraffins is disclosed. The process generally comprises the use of a hydrocracking catalyst comprising an unsulfided low acidity noble metal containing zeolite. The invention is useful for making lighter n-paraffin products for various applications, generally including upgrading hydrocarbon feedstocks to produce fuels, solvents, lubricants, chemicals and other hydrocarbonaceous compositions, and more particularly, as feedstocks for ethylene and linear alkyl benzene production and as jet and diesel fuel blend components.
1 . A process for selectively producing hydrocracked n-paraffins from heavy n-paraffins comprising contacting a hydrocarbon feed comprising heavy n-paraffins with a hydrocracking catalyst comprising an unsulfided low acidity platinum containing zeolite under hydrocracking conditions to produce a hydrocarbon product comprising hydrocracked n-paraffins, wherein the zeolite is a USY zeolite, ZSM-12, or a combination thereof;
wherein the zeolite silica-to-alumina ratio is at least about 70 and the zeolite silica-to-alumina ratio is of a sufficient value or range to selectively produce n-paraffin products over isoparaffin products; and
wherein the fractional yield of hydrocracked n-paraffin product is at least about 10 mol % greater than a corresponding fractional yield obtained using a hydrocracking catalyst that differs only in having a zeolite silica-to-alumina ratio that is no greater than about 60.
2 . The process of claim 1 , wherein the zeolite silica-to-alumina ratio is at least about 80, or 90, or 100, or 110, or 120.
3 . The process of claim 1 , wherein the zeolite does not contain boron.
4 . The process of claim 1 , wherein the zeolite comprises USY and ZSM-12.
5 . The process of claim 1 , wherein the heavy n-paraffins comprise C 12+ n-paraffins, or are predominantly C 12+ n-paraffins, or wherein the C 12+ content is greater than about 50 wt %, or 60, or 70, or 80, or 90, or 95, or 98, or is about 100%.
6 . The process of claim 1 , wherein the hydrocracking conditions comprise a temperature of about 270° C. to about 330° C., a pressure in the range of about 200 psig to about 2000 psig and a space velocity in the range of about 0.4 to about 2.0 LHSV hr −1 .
7 . The process of claim 1 , wherein the molar yield ratio of hydrocracked n-paraffin product to i-paraffin product in the C 4 to C 13 range for n-hexadecane conversion varies from about 2 to about 8.5.
8 . The process of claim 1 , wherein the fractional yield of hydrocracked n-paraffin product is at least about 20, or 30, or 40, or 50, or 60, or 70, or 80, or 90, or 100 mol % greater.