Fixed bed reactor assembly having a guard catalyst bed

A down-flow fixed bed reactor assembly comprising a reactor vessel having a reactor wall including an internal cylindrical wall;

• a catalyst bed support means coupled to and supported by the internal cylindrical wall of said reactor wall of said reactor vessel for supporting an essentially fixed catalyst bed in an upper hydroconversion reaction zone and for allowing a hydrocarbon feed stream to pass therethrough while preventing catalyst particles from an essentially fixed catalyst bed to exit therethrough;
• a container means disposed in proximity to said catalyst bed support means for assisting in slurrying generally spent catalyst particles from an essentially fixed catalyst bed in an upper hydroconversion reaction zone above said catalyst bed support means;
• a hydrocarbon conduit means, passing through said reactor wall of said reactor vessel and communicating with said container means, for introducing a hydrocarbon into said container means for assisting in slurrying generally spent catalyst particles from an essentially fixed catalyst bed in an upper hydroconversion reaction zone of said reactor vessel;
• a catalyst outlet means, passing through said reactor wall of said reactor vessel and communicating with said container means, for withdrawing a generally spent catalyst particles in slurry form from an upper hydroconversion reaction zone in said reactor vessel;
• and at least one lower hydroconversion reaction zone, serially disposed in said reactor vessel under said catalyst bed support means, for containing at least one fixed catalyst bed.