Disclosed is an apparatus for distributing a generally downwardly flowing liquid-vapor mixture through a bed of solid particles comprising:(1) a tray deck located above said bed of solid particles;(2) at least one hollow chimney member in fluid communication with said bed of solid particles attached to said tray deck and extending upwardly from said tray deck, said chimney member having at least one aperture through said chimney member along the length of said chimney member below the top opening of said chimney member to provide fluid communication between the space above said tray deck and the hollow space of said chimney member; and(3) plate means located at a distance D above the top opening of said chimney member whereby said mixture is restricted from flowing directly into the top opening of said chimney member.An improved process for distributing a generally downwardly flowing liquid-vapor mixture is disclosed as well as an improved process for hydrocarbon conversion.