NOVELTY - Pyrolysis reactor for processing municipal and domestic wastes includes pyrolysis chamber (38) including a three-cavity retort (36), which includes an elongated horizontally arranged hollow body having 2 lower parallel and cylindrical cavities. Two waste-feeding screws (40, 42) that have threads with outer surfaces are located in the cavities, respectively. They are tapered in shapes with a taper angle that decreases the diameters of waste-feeding screws from the inlet device to the outlet device. The waste-feeding screws have a gap between their outer surfaces.    USE - Pyrolysis reactor for processing solid municipal and domestic wastes.    ADVANTAGE - The reactor has simple construction; and provides efficiency in the pyrolysis reaction, sufficient compaction of the waste material for displacement of air from the material being treated, efficient mixing of the material being treated, and efficient loading, unloading of the material into and from the reactor along with efficient conveyance of the material through the reactor. It has a structure having a low metal-to-power ratio, and thus, low manufacturing cost. The gap in the waste-feeding screws prevents the wastes from accumulation inside the retort. It is separated into 2 parts by an edge that divides the flow of the mixed wastes into 2 separate sub-flows. This provides movement of the wastes along the walls of the pyrolysis reactor and prolongs time of contact of the wastes with the hot walls of the retort, thus improving efficiency of the process.    DETAILED DESCRIPTION - Pyrolysis reactor for processing municipal and domestic wastes comprises pyrolysis chamber (38), reactor dual-gate type loading mechanism (39) for loading the pyrolysis chamber with wastes without access of oxygen to the pyrolysis chamber, and a reactor dual-gate type unloading mechanism (39') for unloading the pyrolysis chamber from solid residual products of pyrolysis without access of oxygen to the pyrolysis chamber. The pyrolysis chamber comprises an inlet device, an outlet device, and a three-cavity retort (36) comprising an elongated horizontally arranged hollow body having 2 lower parallel and cylindrical cavities and an upper syngas guiding chamber with vertical walls. Two waste-feeding screws (40, 42) that have threads with outer surfaces are located in the cavities, respectively. They are tapered in shapes with a taper angle that decreases the diameters of waste-feeding screws from the inlet device to the outlet device. The waste-feeding screws have a gap between their outer surfaces.    DESCRIPTION OF DRAWING(S) - The drawing is a longitudinal sectional view of pyrolysis reactor.    Three-cavity retort (36)    Pyrolysis chamber (38)    Reactor dual-gate type loading mechanism (39)    Reactor dual-gate type unloading mechanism (39')    Waste-feeding screws (40, 42)