NOVELTY - The pyrolysis of a pyrolyzable mass in the form of particles is treated by supplying carrier particles and pyrolyzable particles (A, B) at specified rates.    USE - Used for the pyrolysis of a pyrolyzable mass in the form of particles    ADVANTAGE - The process reduces energy losses caused by mixing the pyrolyzable mass with carrier particles.    DETAILED DESCRIPTION - The pyrolysis of pyrolyzable mass in the form of particles are treated in the presence of carrier particles at elevated temperature, yielding a combustible product. The carrier particles are heated and contacted with the pyrolyzable particles and are mixed. The mixture (C) of particles and heated carrier particles in a reactor yielding a hot, gaseous, combustible product and a pyrolyzable mass-depleted mixture. The pyrolyzable mass-depleted mixture is removed for heating the carrier particles. The carrier particles are supplied at a rate A and the pyrolyzable particles at a rate B, and mixing is carried out such that by using a method of mixing from mixing by means of a rotating element, where the pyrolyzable particles and the carrier particles at the center of the rotating element come into contact with the rotating element and the rotating element rotates at a speed such that the pyrolyzable particles and the carrier particles move over the surface of the rotating element to be hurled away; mixing by means of a vibrating or shaking element, and the pyrolyzable particles and the carrier particles leave the vibrating or shaking element over an edge or hole, and mixing at a volume density of less than 40%; and that before the mixture is deposited it is mixed at a well enough that in a sample of 1 cubic decimeter of the obtained mixture the A/B ratio deviates less than 20% from the ratio at which A and B are added, and the mixture obtained is deposited, and in a condition after pouring undergoes pyrolysis in the reactor.    DESCRIPTION OF DRAWING(S) - The figure is a schematically depicts an apparatus.    Apparatus (1)    Chambers (2, 3)    Pyrolyzable particles (A)    Mixture (C)    Pyrolysis product (D)