GB574892A - Process and apparatus for the conversion of fluid reactants - Google Patents

Abstract

<PICT:0574892/IV/1> In a process for the conversion of fluid reactants during their upward flow through a vertically elongated fluidized bed of subdivided solid contact material in a reaction zone, the improvement which comprises subdividing the fluidized bed of solid particles into a plurality of superimposed sections between a plurality of substantially horizontal perforated distributing plates, extending over the entire cross-sectional area of the reaction zone and vertically spaced along the major portion of the height of the bed. The process is applicable to catalytic hydrogen conversion reactions such as hydrogenation, dehydrogenation, cyclization, hydro-reforming, and dehydrocyclization. By means of the redistributing plates, channelling is reduced and uniformity of contact is increased so that it is possible to increase the conversion at a given space velocity or use higher space velocities at a given conversion level. In the Figure, liquid or vaporous hydrocarbons are supplied through line 4, commingled with hot regenerated catalyst particles (from regenerator 22) in line 6, and the suspension passed into reactor 7 through the distributing grid 11. A fluidized catalyst bed is maintained in the reactor and this is divided into several sections by means of perforated plates 12 which are located at substantially equally-spaced distances intermediate the upper and lower ends of the bed; the perforations being sufficiently large to permit flow of catalyst particles from one section to the next. Contaminated catalyst passes downwardly through standpipe 17 and is admitted through valve 18 into transfer line 19 where it meets a stream of air or other oxidizing gas which transports the particles into the regenerator 22. In a modification, provision is made for withdrawing catalyst for regeneration from any one or all of the separate sections of the dense phase fluidized bed in the reactor. A process is also described wherein the flow of catalyst particles through the reactor is downward counter-current to the ascending stream of reactants, i.e. catalyst is supplied from the regenerator to the upper portion of the reactor. In an example, the dehydrogenation of normal butane using an alumina catalyst containing 2 per cent MgO and 12 per cent Cr2O3 is described.