Method for capturing organometallic impurities in the presence of a capture mass on a mesoporous-macroporous support
The invention relates to a method for capturing organometallic impurities in a gasoline-type hydrocarbon feedstock containing sulfur compounds and olefins, wherein said feedstock is brought into contact with hydrogen and a capture mass comprising a nickel-based active phase, and a mesoporous and macroporous alumina substrate having a bimodal distribution of mesopores and wherein: —the volume of mesopores having a diameter greater than or equal to 2 nm and less than 18 nm corresponds to between 10 and 30% by volume of the total pore volume of said substrate; —the volume of mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to between 30 and 50% by volume of the total pore volume of said substrate.
1. A process for capturing organometallic impurities in a gasoline-type hydrocarbon feedstock containing sulfur compounds and olefins, comprising:
bringing a capture mass into contact with a feedstock to be treated and a flow of hydrogen at a temperature between 200 and 400° C., a pressure of between 0.2 and 5 MPa and a ratio of the hydrogen flow rate to the hydrocarbon feedstock flow rate of between 50 and 800 Nm 3/ m 3 ,
said capture mass comprising an active phase based on nickel, and a support of mesoporous and macroporous alumina comprising a bimodal distribution of mesopores, and in which:
the volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to between 10 and 30% by volume of the total pore volume of said support;
the volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to between 30 and 50% by volume of the total pore volume of said support;
the volume of the macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to between 30 and 50% by volume of the total pore volume of said support,
wherein said support is in the form of beads with a diameter of between 2 and 4 mm and said support is obtained according to the following method:
s1) dehydration of an aluminum hydroxide or an aluminum oxyhydroxide at a temperature of between 400° C. and 1200° C., for a time of between 0.1 second and 5 seconds, to obtain an alumina powder;
s2) shaping of said alumina powder obtained in s1) in the form of beads;
s3) heat treatment of the alumina beads obtained in s2) at a temperature greater than or equal to 200° C.;
s4) hydrothermal treatment of the alumina beads obtained at the end of s3) by impregnation with water or an aqueous solution, then residence in an autoclave at a temperature between 100° C. and 300° C.;
s5) calcining of the alumina beads obtained at the end of s4) at a temperature between 500° C. and 820° C.
2. The process as claimed in claim 1 , wherein said support has a specific surface area of between 50 and 210 m 2 /g.
3. The process as claimed in claim 1 , wherein said support has a total pore volume of between 0.7 and 1.3 mL/g.
4. The process as claimed claim 1 , wherein the volume of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm corresponds to between 15 and 25% by volume of the total pore volume of said support.
5. The process as claimed in claim 1 , wherein the volume of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm corresponds to between 35% and 45% by volume of the total pore volume of said support.
6. The process as claimed in claim 1 , wherein the volume of the macropores with a diameter greater than or equal to 50 nm and less than 8000 nm corresponds to between 35 to 50% by volume of the total pore volume of said support.
7. The process as claimed in claim 1 , wherein the nickel content, expressed in NiO form, is between 5 and 65% by weight relative to the total weight of said capture mass.
8. The process as claimed in claim 1 , wherein the active phase consists solely of nickel.
9. The process as claimed in claim 1 , wherein the active phase of said capture mass further comprises cobalt, molybdenum and phosphorus.
10. The process as claimed in claim 9 , wherein the nickel content, expressed in NiO oxide form, is between 5 and 65% by weight relative to the total weight of said capture mass, the cobalt content, expressed in CoO form, is between 0.5 and 10% by weight relative to the total weight of said capture mass, the molybdenum content, expressed in MoO 3 form, is between 2 and 20% by weight relative to the total weight of said capture mass, and the phosphorus content, expressed in P 2 O 5 form, is between 0.2 and 10% by weight relative to the total weight of said capture mass.
11. The process as claimed in claim 1 , wherein the pore distribution of the mesopores with a diameter greater than or equal to 2 nm and less than 18 nm is centered on a range of values between 10.5 and 14.5 nm.
12. The process as claimed in claim 1 , wherein the pore distribution of the mesopores with a diameter greater than or equal to 18 nm and less than 50 nm is centered on a range of values of between 22 and 28 nm.
13. The process as claimed in claim 1 , wherein said support comprises a specific surface area of between 70 and 180 m2/g.
14. The process as claimed in claim 1 , wherein said support is in the form of beads with a diameter of between 2 and 4 mm.
15. The process as claimed in claim 1 , wherein the hydrocarbon feedstock is a catalytic cracking gasoline containing between 5% and 60% by weight of monoolefins, between 50 and 6000 ppm by weight of sulfur compounds and between 10 and 1000 ppb of arsenic relative to the total weight of said feedstock.
16. The process as claimed in claim 1 , wherein the organometallic impurities are selected from organometallic impurities of heavy metals, silicon, phosphorus and arsenic.
17. The process as claimed in claim 1 , wherein the dehydration of aluminum hydroxide or aluminum oxyhydroxide is performed at a temperature of between 600° C. and 900° C.
18. The process as claimed in claim 1 , wherein the dehydration of aluminum hydroxide or aluminum oxyhydroxide is performed for a time of between 0.1 second and 4 seconds.
19. The process as claimed in claim 17 , wherein the dehydration of aluminum hydroxide or aluminum oxyhydroxide is performed for a time of between 0.1 second and 4 seconds.