Catalyst pellet

Claim 2

A SHAPED CATALYST PELLET IN THE FORM OF A CYLINDER HAVING AT LEAST ONE INDENTATION OR PROTRUSION FORMED ON AT LEAST ONE OF ITS END SURFACES SAID CATALYST PELLET BEING MADE FROM MATERIALS SELECTED FROM THE GROUP CONSISTING OF OXIDES OF GROUP II TO GROUP VIII METALS METALS FROM GROUP IB AND GROUP VIII OF THE PERIODIC TABLE HYDRAULIC CEMENTS, SILICA AND ALUMINA, SAID PELLET BEING ONE IN WHICH THE RATIO (LE - LI)/D IS GREATER THAN 0.25 AND LI IS BETWEEN 0.05 D AND 0.6 D, WHERE LE IS THE OVERALL HEIGHT OF THE PELLET MEASURED FROM ITS EXTREMITIES LI IS THE LENGTH OF SOLID-FILLED VOLUME OVER WHICH THE CROSS SECTIONAL AREA PERPENDICULAR TO THE AXIS OS 1/4 D2 AND THE DIAMETER IS D THE RATIO LE/D BEING BETWEEN 2.0 AND 0.5 TO 1 AND D HAVING A VALUE OF 1.5 TO 10 MM.

Claim 3

A catalyst pellet according to claim 1 in which at least one indentation is conical or frusto-conical.

Claim 4

A catalyst pellet according to claim 1 in which an indentation is in the form of a groove.

Claim 5

A catalyst pellet according to claim 1 in which a protrusion is in the form of a ridge.

Claim 6

A catalyst pellet according to claim 1 having a length and diameter less than 10 mm.

Claim 7

A catalyst bed comprising a mixture of cylindrical catalyst pellets each formed with at least two end surfaces, each surface having at least one irregularity which is a groove or ridge, wherein each component of the mixture consists of pellets having a like orientation of the irregularity on one surface with respect to that on another surface, and the orientation is different in other cOmponents of the mixture, said catalyst pellets being made from materials selected from the group consisting of oxides of Group II to Group VIII metals, metals from Group IB and Group VIII of the Periodic Table, hydraulic cements, silica and alumina, said pellet being one in which the ratio (LE-LI/D) is greater than 0.25 and LI is between 0.05D and 0.6D, where LE is the overall height of the pellet measured from its extremities, LI is the length of solid-filled volume over which the cross-sectional area perpendicular to the axis is 1/4 pi D2 and the diameter is D, the ratio LE/D being between 2.0 and 0.5 to 1 and D having a value of 1.5 to 10 mm.

Claim 8

A catalyst bed comprising a mixture of cylindrical catalyst pellets each formed with at least two end surfaces, each surface having at least one irregularity which is a groove or ridge, wherein each component of the mixture consists of pellets having a like orientation of the irregularity on one surface with respect to that on another surface, and the orientation is different in other cOmponents of the mixture, said catalyst pellets being made from materials selected from the group consisting of oxides of Group II to Group VIII metals, metals from Group IB and Group VIII of the Periodic Table, hydraulic cements, silica and alumina, said pellet being one in which the ratio (LE-LI/D) is greater than 0.25 and LI is between 0.05D and 0.6D, where LE is the overall height of the pellet measured from its extremities, LI is the length of solid-filled volume over which the cross-sectional area perpendicular to the axis is 1/4 pi D2 and the diameter is D, the ratio LE/D being between 2.0 and 0.5 to 1 and D having a value of 1.5 to 10 mm.