An apparatus for introducing fluids into a solids flow of a spouted bed apparatus is provided. The apparatus includes a spray nozzle which opens into a reaction space of the spouted bed apparatus. A lower region of the reaction space is provided with a rectangular cross section for the spouted bed apparatus and is limited in an axial direction by at least one inclined stream return flow wall and an oppositely inclined stream inlet wall with the formation of an axial gap through the reaction space for supplying inlet air. At least one nozzle is also provided for introducing fluid above the gap opens into the reaction space.