A bladed reactor for the pyrolysis of hydrocarbons, including a rotor with blades forming an axial-flow blade cascade, and a housing having inlet and outlet ports, said housing enclosing this rotor and stationary vanes, wherein: - a fixed guide torus-shaped hoop is installed in the housing and the hoop adjoins tips of the blades, the housing encloses a rotor periphery and the hoop so that a passage is formed, the meridian section of the passage has a ring shape; - two or more partitions or several partitions are installed in the passage symmetrically relative to a rotor axis, said partitions define boundaries of two or more identical working cavities, wherein in every working cavity the inlet port is located just after the partition in a rotor rotation direction, and the outlet port is located just before the next partition; - geometrical parameters of the blade cascade and stationary vanes are such that when the rotor rotates the fluid in each working cavity is forced to move from the inlet port to the outlet port along a helical trajectory, - the stationary vanes include nozzle vanes forming nozzle cascades and diffusing vanes forming diffusing cascades, the nozzle cascades and diffusing cascades are located in each working cavity upstream and downstream of the blade cascade, respectively, so that a vaneless reaction space is formed between an outlet of the diffusing cascade and an inlet of the nozzle cascade, - a gap between the housing and the guide hoop in this vaneless reaction space are sufficiently great to provide in operation practically the same pressure at an outlet of the diffusing cascade throughout a length of said cascade, characterized in that the rotor blades are located near each other and aligned with respect to each other such that the blades pass radially outward from an axis of rotation, the blades being installed by their concave side in a rotor rotation direction, whereby the axial-flow blade cascade is formed, wherein each of the blades has a profile of an impulse turbine blade, and in that rings (16, 17) are fastened in the housing and are configured to be adjustable in a circumferential direction relative to the rotor axis. - a fixed guide torus-shaped hoop is installed in the housing and the hoop adjoins tips of the blades, the housing encloses a rotor periphery and the hoop so that a passage is formed, the meridian section of the passage has a ring shape; - two or more partitions or several partitions are installed in the passage symmetrically relative to a rotor axis, said partitions define boundaries of two or more identical working cavities, wherein in every working cavity the inlet port is located just after the partition in a rotor rotation direction, and the outlet port is located just before the next partition; - geometrical parameters of the blade cascade and stationary vanes are such that when the rotor rotates the fluid in each working cavity is forced to move from the inlet port to the outlet port along a helical trajectory, - the stationary vanes include nozzle vanes forming nozzle cascades and diffusing vanes forming diffusing cascades, the nozzle cascades and diffusing cascades are located in each working cavity upstream and downstream of the blade cascade, respectively, so that a vaneless reaction space is formed between an outlet of the diffusing cascade and an inlet of the nozzle cascade, - a gap between the housing and the guide hoop in this vaneless reaction space are sufficiently great to provide in operation practically the same pressure at an outlet of the diffusing cascade throughout a length of said cascade,