Catalyst, catalyst precursor, and catalyst carrier
A catalyst, catalyst precursor, or catalyst carrier formed as an elongated shaped particle having a cross section comprising three protrusions each extending from and attached to a central position. The central position is aligned along the longitudinal axis of the particle. The cross-section of the particle occupies the space encompassed by the outer edges of six outer circles around a central circle, each of the six outer circles contacting two neighbouring outer circles, the particle occupying three alternating outer circles equidistant to the central circle and the six interstitial regions, the particle not occupying the three remaining outer circles which are between the alternating occupied outer circles. The ratio of the diameter of the central circle to the diameter of the outer occupied circle is more than 1, and the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than 1. The ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than the ratio of the diameter of the central circle to the diameter of the outer occupied circle.
1. A catalyst carrier formed as an elongated shaped particle having a cross section comprising three protrusions each extending from and attached to a central position, wherein the central position is aligned along the longitudinal axis of the particle, the cross-section of the particle occupying the space encompassed by the outer edges of six outer circles around a central circle, each of the six outer circles contacting two neighbouring outer circles, the particle occupying three alternating outer circles equidistant to the central circle and the six interstitial regions, the particle not occupying the three remaining outer circles which are between the alternating occupied outer circles;
wherein the ratio of the diameter of the central circle to the diameter of the outer occupied circle is more than 1.4 and the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than 1.3;
and wherein the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than the ratio of the diameter of the central circle to the diameter of the outer occupied circle.
2. A catalyst carrier according to claim 1 , wherein the ratio of the diameter of the central circle to the diameter of the outer occupied circle is less than about 2.5.
3. A catalyst carrier as claimed in claim 1 , wherein the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than 1.5.
4. A catalyst carrier as claimed in claim 1 , wherein the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is less than about 2.0.
5. A catalyst carrier as claimed in claim 1 , wherein each outer circle tangentially contacts the central circle.
6. A catalyst carrier as claimed in claim 1 , wherein said contact between each outer circle and two neighbouring circles is tangential.
7. A catalyst carrier as claimed in claim 1 , wherein the nominal diameter of the particle is 0.5-6 mm.
8. A catalyst carrier as claimed in claim 1 , wherein the particles have a length/diameter ratio (L/D) of between 1 and 10.
9. A catalyst comprising a catalyst carrier as claimed in claim 1 , and a catalytically active metal or precursor therefor supported on the catalyst carrier; wherein the catalytically active metal is selected from elements of Group VIII of the Periodic Table of the Elements.
10. A catalyst as claimed in claim 9 , wherein the catalyst carrier comprises a porous refractory metal oxide.
11. A catalyst as claimed in claim 9 , wherein the catalytically active metal is cobalt or iron.
12. A hydrocracking catalyst comprising a metal having hydrogenation activity, and supported on a catalyst carrier as defined in claim 1 and comprising an acidic function.
13. A method of manufacturing a catalyst carrier comprising:
(a) mixing a catalyst carrier with a liquid to form a paste;
(b) adding said paste to an extruder, the extruder having a die plate comprising one or more dies, each die having a plurality of apertures;
(c) extruding the paste through said apertures to form catalyst carrier extrudates;
(d) wherein the apertures define a cross sectional shape comprising three protrusions each extending from and attached to a central position, wherein the central position is aligned along the longitudinal axis of the particle, the cross-section of the particle occupying the space encompassed by the outer edges of six outer circles around a central circle, each of the six outer circles contacting two neighbouring outer circles, the particle occupying three alternating outer circles equidistant to the central circle and the six interstitial regions, the particle not occupying the three remaining outer circles which are between the alternating occupied outer circles;
wherein the ratio of the diameter of the central circle to the diameter of the outer occupied circle is more than 1.4 and the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than 1.3;
and wherein the ratio of the diameter of the outer unoccupied circle to the diameter of the outer occupied circle is more than the ratio of the diameter of the central circle to the diameter of the outer occupied circle.
14. The method as claimed in claim 13 , wherein an active metal or active metal precursor is mixed with the catalyst carrier in step (a) to form a paste.
15. The method as claimed in claim 13 , wherein the catalyst carrier comprises a refractory metal oxide or a precursor thereof.
16. The method as claimed in claim 15 , wherein an active metal or active metal precursor is mixed with the catalyst carrier in step (a) to form a paste.