Processes for reacting high flow rates of one or more gaseous reactants in
tubular reactors. The improved processes allow such reactions to be
carried out with a low pressure drop across the reactor and without
excessive erosion due to solid particles carried with or picked up by the
gaseous reactants. A process of this invention is basically comprised of
the steps of swirling a gaseous reactant which may contain or pick up
solid particles in a first annular plenum chamber followed by a second
larger diameter annular plenum chamber and then introducing the gaseous
reactant and solid particles into a reactor by way of two or more radial
slots whereby the gaseous reactant and solid particles are caused to flow
into the reactor and are uniformly distributed therein.