Process and device for withdrawing solid particles and introducing a liquid charge at the lower portion of a contact zone

In a process for introducing into a reaction zone, containing catalyst particles, a fluid charge consisting essentially of at least one liquid and one gas of high hydrogen content, said zone having substantially an elongate and substantially vertical cylindrical shape, with the catalyst particles being introduced at the upper part of said reaction zone and progressively withdrawn from the lower part of the reaction zone after progressing downwardly through said reaction zone, with the fluid charge being introduced at least partly in the lower part of said reaction zone and withdrawn from the upper part thereof after progressing upwardly through said reaction zone, and wherein the catalyst particles are withdrawn from the lower end of at least one flared zone having the shape of an inverted cone or pyramid with the top thereof turned downwardly, the average angle between the axis of the cone or pyramid and one of the cone generatrices or one of the pyramid solid angles being from 10.degree.-80.degree., the downwardly turned top having at least one opening of a size sufficient for discharging the catalyst particles, and the walls of said flared zone being substantially and regularly discontinuous by having at least a plurality of regularly spaced openings of a sufficiently small size to prevent the catalyst particles from passing through said walls, but sufficiently large to permit passage, through said openings, of an upward stream of at least a part of the fluid charge, the improvement wherein at least a portion of the fluid charge is injected in the lower part of said reaction zone through a main pipe which is subdivided into at least one tube respectively for said at least one flared zone, said at least one tube being substantially vertical along the axis of the cone or pyramid of said at least one flared zone and subdivided in the vicinity of the downwardly turned top of said cone or pyramid into a plurality of ducts substantially parallel to the generatrices of the cone or to the walls of the pyramid and located below said walls, and with orifices provided along said ducts beklow said walls of said cone or pyramid, and with each orifice being located at a distance from said walls of said cone or pyramid at least equal to the average size of the catalyst particles fed into the reaction zone and at most equal to about 500 times the average size of said catalyst particles.

In an apparatus for carrying out a process for withdrawing solid particles and introducing a liquid charge at the lowest portion of a contact zone, comprising a reactor (1), first introducing means (2) for introducing fresh catalyst at the upper part of the reactor, first discharge means for discharging used catalyst at the lower part of said reactor, with said first discharge means comprising at least one withdrawal funnel (4) of an inverted conical or pyramidal shape, with the angle between the axis of the cone or of the pyramid with one of the generatrices of the cone or one of the solid angles of the pyramid being 10.degree.-80.degree. and with the top of the cone or pyramid oriented downwardly, at least one opening (5) sufficiently large for permitting discharge of used catalyst from the reactor, and located at said downwardly oriented top, second introducing means (8) for introducing a fluid charge at the lower part of the reactor and second discharge means (10) for discharging a treated fluid charge from the upper part of the reactor, the walls of said withdrawing funnel (4) having perforations (6) substantially distributed over the surface of said funnel, with the size of said perforations being sufficiently small to prevent the passage of catalyst particles through said walls, but sufficiently large to provide for passage through said walls of an upward stream of at least a portion of a fluid charge introduced into the apparatus, the improvement wherein said second introducing means (8) for introducing the fluid charge comprises a plurality of substantially vertical ducts (9) provided with orifices (11) for introducing at least a portion of the fluid charge, said orifices being located either above or below, or both above and below said walls of said cone or pyramid, and at a distance from said walls of said cone or pyramid at least equal to the average size of catalyst particles to be introduced and at most equal to about 10 cm.

In an apparatus for carrying out a process for withdrawing solid particles and introducing a liquid charge at the lower portion of a contact zone, comprising a reactor (1), first introducing means (2) for introducing fresh catalyst at the upper part of the reactor, first discharge means for discharging used catalyst at the lower part of said reactor, with said first discharge means comprising at least one withdrawal funnel (4) of an inverted conical or pyramidal shape, with the angle between the axis of the cone or of the pyramid with one of the generatrices of the cone or one of the solid angles of the pyramid being 10.degree.-80.degree. and with the top of the cone or pyramid oriented downwardly, at least one opening (5) sufficiently large for permitting discharge of used catalyst from the reactor, and located at said top, second introducing means (8) for introducing a fluid charge at the lower part of the reactor and second discharge means (10) for discharging a treated fluid charge from the upper part of the reactor, the walls of said withdrawing funnel (4) having perforations (6) substantially distributed over the surface of said funnel, with the size of said perforations being sufficiently small to prevent the passage of catalyst particles through said walls, but sufficiently large to provide for passage through said walls of an upward stream of at least a portion of a fluid charge introduced into the apparatus, the improvement wherein said second introducing means (8) for introducing the fluid charge comprises a bundle of ascending branch pipe (9) substantially parallel to the walls of the funnel and located below said walls, said pipes (9) having openings for injecting at least a portion of the charge therethrough, and said openings being located below said walls and at a distance from said walls at least equal to the average size of catalyst particles to be introduced into the apparatus and at most equal to about 10 cm.