NOVELTY - A pyrolysis device comprises a reactor space designed such that direct flow from biomass feed (10) and heated heat carrier material feed (11) to a pyrolysis gas discharge (13) is blocked. A mechanical mixer (18) in the reactor space mixes the incoming flows of biomass material and preheated heat carrier material. The maximum average velocity of the gas and the entrained material in the reactor space downstream of mixer at 400-550 degrees C is as great as the terminal falling velocity.    USE - A pyrolysis device for pyrolyzing biomass.    ADVANTAGE - Any clogging and blocking can be effectively prevented from occurring, despite the carbon and other solid material being of a tacky nature. Carbon and non-converted fibers and heat carrier material are discharged only via solid material discharge and the pyrolysis discharge discharges only pyrolysis gas. All solid particles are separated from the pyrolysis gas in one part of the reactor where the mechanical mixer is situated. The separation between the discharge flows of pyrolysis gas and solid material takes place only under the gravitational force, since the average velocity of the gas and the entrained solid material has a low value downstream of mixer. The device does not comprise a cyclone.    DETAILED DESCRIPTION - A pyrolysis device comprises a reactor (6) with a housing (7) and a reactor space; a feed (10) for biomass material (5) or other organic material connecting to an upper zone (9) of the reactor space; a feed (11) for heated heat carrier material (12), e.g. sand, connecting to the upper side of the reactor space; a discharge (13) for pyrolysis gas (14) connecting to the upper zone of the reactor space at a distance from the biomass material feed; and a discharge (16) for solid material (17), e.g. carbon and heat carrier material, connecting to the underside of the reactor space. The reactor space is designed such that the direct flow from the feeds to the pyrolysis gas discharge is blocked. A mechanical mixer (18) in the reactor space mixes the incoming flow of biomass material with the incoming flow of preheated heat carrier material. The maximum average velocity of the gas and entrained material in the reactor space downstream of the mixer at 400-550 degrees C is as great as the terminal falling velocity such that separation between the respective discharge flows of pyrolysis gas and solid material takes place under the influence of gravitational force, particularly without interposing of a cyclone.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a reactor.    Biomass material (5)    Reactor (6)    Housing (7)    Upper zone (9)    Biomass feed (10)    Heated heat carrier material feed (11)    Preheated heat carrier material (12)    Pyrolysis gas discharge (13)    Pyrolysis gas (14)    Lower zone (15)    Solid material discharge (16)    Solid material (17)    Mechanical mixer (18)    Vertical baffle (19)    Upper wall (20)    Wall (23)    Mixer space (24)