Nanoscale nickel phosphide catalysts for hydrotreatment

Abstract

This present disclosure is directed to methods for the preparation of a hydrotreatment catalyst, such as nanoscale nickel phosphide (i.e., Ni2P) particles supported on high-surface area metal oxides (e.g., silica, alumina, amorphous silica-alumina), in a manner that is compatible with conditions employed in commercial hydrotreating units. The catalyst synthesis includes impregnation, drying, and in situ reduction, and can provide highly active catalysts for the removal of S and N impurities from crude oil fractions.

1 - 28 . (canceled) 
     
     
         29 . A hydrotreatment catalyst comprising nanoscale Ni 2 P particles on a support, wherein the nanoscale Ni 2 P particles are in the form of a plurality of Ni 2 P crystallites on the support, and the plurality of crystallites has an average diameter of 3 nm to 15 nm; and
 wherein the support is selected from the group consisting of silica, alumina, and amorphous silica-alumina; the support optionally comprising a surface layer comprising P 2 O 5 , B 2 O 3 , or a combination thereof.   
     
     
         30 . The hydrotreatment catalyst of  claim 29 , wherein the hydrotreatment catalyst does not comprise an inorganic salt. 
     
     
         31 . The hydrotreatment catalyst of  claim 29 , wherein the hydrotreatment catalyst does not include impurities. 
     
     
         32 . The hydrotreatment catalyst of  claim 29 , wherein the impurities comprise Ni 12 P 5 . 
     
     
         33 . The hydrotreatment catalyst of  claim 29 , wherein the plurality of crystallites has a diameter that does not vary by more than 20% compared to the average diameter. 
     
     
         34 . The hydrotreatment catalyst of  claim 29 , wherein the nanoscale Ni 2 P particles are 5 wt % to 25 wt % of the hydrotreatment catalyst and wherein the nanoscale Ni 2 P particles have a surface composition comprising a mole ratio of P/Ni of 1.0-6.0. 
     
     
         35 . The hydrotreatment catalyst of  claim 34 , wherein the nanoscale Ni 2 P particles have a bulk portion below the surface composition, having a mole ratio of P/Ni that is less than that of the surface composition. 
     
     
         36 . The hydrotreatment catalyst of  claim 29 , wherein the surface layer of the support, when present, has a thickness of 5 nm, and wherein the catalyst has a BET surface area of from 75 m 2 /g to 250 m 2 /g. 
     
     
         37 . The hydrotreatment catalyst of  claim 29 , having a carbazole hydrodenitrogenation turnover frequency of from 0.0001/s to 0.0006/s at 350° C. over a time period of 24 hours to 120 hours, when exposed to 1000 ppm carbazole and 3000 ppm benzothiophene in a 60 wt % decane and 39.55 wt % p-xylene solvent mixture at a rate of 5.4 mL/min, and a H 2  flow rate of 50.0 mL/min, at a temperature of about 267° C. to 407° C. and a pressure of 3.0 MPa. 
     
     
         38 . The hydrotreatment catalyst of  claim 29 , wherein when the nanoscale Ni 2 P particles are 5 wt % to 25 wt % of the hydrotreatment catalyst, the hydrotreatment catalyst is capable of providing a carbazole hydrodenitrogenation conversion of 1% to 97% at 350° C. over a time period of 24 hours to 120 hours, when exposed to 1000 ppm carbazole and 3000 ppm benzothiophene in a 60 wt % decane and 39.55 wt % p-xylene solvent mixture at a rate of 5.4 mL/min, and a H 2  flow rate of 50.0 mL/min, at a temperature of about 267° C. to 407° C. and a pressure of 3.0 MPa. 
     
     
         39 . The hydrotreatment catalyst of  claim 29 , wherein when the nanoscale Ni 2 P particles are 5 wt % to 25 wt % of the hydrotreatment catalyst, the hydrotreatment catalyst is capable of providing a 4,6-dimethyldibenzothiophene hydrodesulfurization conversion of 1% to 65% at 300° C. over a time period of 24 hours to 120 hours, when exposed to 1000 ppm of 4,6-dimethyldibenzothiophene in decalin, and a H 2  flow rate of 50.0 mL/min, at a temperature of about 257° C. to 327° C. at a pressure of 3.0 MPa. 
     
     
         40 . The hydrotreatment catalyst of  claim 29 , wherein the hydrotreatment catalyst provides higher proportions of cyclohexylbenzene when exposed to carbazole and benzothiophene, compared to a nickel-molybdenum catalyst on alumina. 
     
     
         41 . A method of hydrotreating a petroleum feedstock, comprising hydrotreating the petroleum feedstock in a reactor using a hydrotreatment catalyst according to  claim 29 . 
     
     
         42 . The method of  claim 41 , wherein the hydrotreatment catalyst is prepared in situ in the reactor prior to hydrotreating the petroleum feedstock, by:
 (a) providing an impregnation solution comprising nickel hydroxide in hypophosphorous acid;   (b) impregnating the support with the impregnation solution;   (c) drying the impregnation solution to provide Ni(H 2 PO 2 ) 2  on the support; and   (d) reducing the Ni(H 2 PO 2 ) 2  on the support in a hydrogen environment, a sulfiding environment or an inert gas environment, and heating at a temperature below a temperature limit of the reactor to provide the hydrotreatment catalyst.   
     
     
         43 . The method of  claim 42 , wherein reducing the Ni(H 2 PO 2 ) 2  comprises heating to a temperature of 400° C. or less in the reactor. 
     
     
         44 . The method of  claim 41 , wherein the method does not include a step of washing the hydrotreatment catalyst prior to hydrotreating the petroleum feedstock. 
     
     
         45 . The method of  claim 41 , wherein the hydrotreatment catalyst is prepared ex situ and then placed in the reactor prior to hydrotreating the petroleum feedstock. 
     
     
         46 . The method of  claim 41 , wherein hydrotreating the petroleum feedstock comprises a reaction catalyzed by the hydrotreatment catalyst that is selected from the group consisting of hydrodenitrogenation; hydrodesulfurization; and hydrogenation; and a combination thereof. 
     
     
         47 . The method of  claim 41 , wherein the petroleum feedstock is a petroleum distillate.