Process and apparatus for catalytic hydrocarbon conversion

A liquid phase process for the catalytic conversion of hydrocarbons or carbon monoxide in the presence of hydrogen, consisting essentially of passing a liquid phase and a hydrogen-containing main gas stream upwardly through at least one catalytic reaction zone comprising several superposed stages, the at least one catalytic reaction zone containing a catalyst bed in each stage which may be either a semi-stationary bed or an ebullated bed, at least one intermediary stage being in permanent communication respectively with the next lower stage and with the preceding upper stage, through a perforated support having multiple openings having small cross-sections of a size smaller than the catalyst particles, and through respective at least one opening having large cross-sections substantially larger than the catalyst particles, the large cross-section openings adapted to allow periodical passage of the catalyst from one stage to another, the process comprising periodically injecting at least one fluid selected from hydrogen, a hydrogen-containing gas and a liquid hydrocarbon, upwardly, from below said openings of relatively large cross-section, at a flow rate and a velocity sufficient to substantially slow down or impede the passage of the catalyst from one stage to the next lower stage through said openings of relatively large cross-section, and periodically discontinuing the injection, or periodically reducing the injection flow rate from below at least one of said openings of relatively large cross-section, to allow passage of the catalyst, downwardly through said at least one of said openings of relatively large cross-section from one stage to the next lower stage.