Goal-Oriented Requirements Engineering

Process for uniformly distributing a fluid such as a gas upwardly through a cylindrical bed of a particulate contact material, preferably a downwardly moving catalyst, without interfering with the downward flow of the material. The contact material of the cylindrical bed is confined within the outer wall of the open bottomed cylindrical chamber while additional contact material is confined under and radially outwardly of the cylindrical chamber. The fluid is introduced into an annular chamber surrounding the outer wall of the cylindrical chamber and caused to flow uniformly around its bottom end downwardly into the additional contact material and then upwardly and uniformly into the cylindrical bed.