Hydro-refining catalyst, carrier for use therein and method for production thereof

1. A method for producing a hydrorefining catalyst for removing heteroelements contained in hydrocarbon oil to be treated comprising:

a step of preparing an aluminum solution containing phosphorus in a molar ratio of 0.001 to 0.05 with respect to aluminum;

a step of neutralizing the prepared aluminum solution to produce a pseudo-boehmite powder;

a step of forming the pseudo-boehmite powder followed by performing calcination at a temperature of not less than 650° C. to obtain a carrier comprised of γ-alumina as the main component wherein the γ-alumina is in crystalline form; and

a step of carrying a hydrogenation-active metal on the pseudo-boehmite powder or the carrier.

2. The method for producing the hydrorefining catalyst according to claim 1 , wherein the calcination temperature is 700° C. to 900° C.

3. The method for producing the hydrorefining catalyst according to claim 1 , wherein the hydrogenation-active metal is carried by impregnating the carrier with a solution containing the hydrogenation-active metal followed by further performing calcination.

4. The method for producing the hydrorefining catalyst according to claim 1 , further comprising a step of kneading the formed pseudo-boehmite powder wherein the hydrogenation-active metal is carried by adding the hydrogenation-active metal during the kneading step of the formed pseudo-boehmite powder.

5. The method for producing the hydrorefining catalyst according to claim 1 , wherein the hydrogenation-active metal is at least one selected from the group consisting of molybdenum, tungsten, cobalt, and nickel.

6. A hydrorefining catalyst which is obtained in accordance with the method as defined in claim 1 .

7. The method for producing the hydrorefining catalyst according to claim 1 , wherein the carrier comprises not less than 80 wt. % of γ-alumina.

8. A carrier for a hydrorefining catalyst for removing heteroelements contained in hydrocarbon oil to be treated comprising:

γ-alumina which is a main component wherein the γ-alumina is in crystalline form; and

phosphorus which is contained in a molar ratio of 0.001 to 0.05 with respect to aluminum, wherein:

a dispersion of a concentration distribution of phosphorus in the carrier is within 10%; and

an exothermic peak temperature, which is brought about by phase transition of γ-alumina into α-alumina when the carrier is subjected to differential thermal analysis, is not less than 1,300° C.

9. The carrier for the hydrorefining catalyst according to claim 8 , wherein the exothermic peak temperature is not less than 1,350° C.

10. The carrier for the hydrorefining catalyst according to claim 8 , wherein a half value width Wγ of a (400) peak of powder X-ray diffraction of γ-alumina satisfies (Wγ/Wα)≦10 with respect to a half value width Wα of a (113) peak of α-alumina.

11. A hydrorefining catalyst comprising:

the carrier for the hydrorefining catalyst as defined in claim 8 , and

a hydrogenation-active metal which is carried on the carrier.

12. The hydrorefining catalyst according to claim 10 , wherein the carrier comprises not less than 80 wt. % of γ-alumina.

13. The carrier for the hydrorefining catalyst according to claim 8 , wherein the carrier comprises not less than 80 wt. % of γ-alumina.