Systems and methods are provided for conversion of methane and/or other hydrocarbons to hydrogen by pyrolysis while reducing or minimizing production of carbon oxides. The conversion of hydrocarbons to hydrogen is performed in one or more pyrolysis or conversion reactors that contain a plurality of sequential fluidized beds. The fluidized beds are arranged so that the coke particles forming the fluidized bed move in a counter-current direction relative to the gas phase flow of feed (e.g., methane) and/or product (H.sub.2) in the fluidized beds. By using a plurality of sequential fluidized beds, the heat transfer and management benefits of fluidized beds can be realized while also at least partially achieving the improved reaction rates that are associated with a plug flow or moving bed reactor.

A system and method for the pyrolysis of a pyrolysis feedstock utilizes a pyrolysis reactor having a pyrolysis conduit and a solids return conduit segment. Each segment is configured with an outlet and an inlet to receive and discharge solid materials that are circulated through the reactor through the different segments. A solids conveyor is disposed within the pyrolysis conduit segment to facilitate conveying solid materials from the solids inlet upward through the pyrolysis conduit segment toward the solids discharge outlet. A pyrolysis feedstock is introduced into the pyrolysis reactor and at least a portion of the feedstock is converted to pyrolysis gases within the pyrolysis conduit segment, which are discharged through a gas outlet. An eductor condenser unit with an eductor assembly having a venturi-restricted flow path for receives a pressurized coolant fluid. A second flow path for receiving the discharged pyrolysis gases intersects the venturi-restricted flow path so that the received pyrolysis gases are combined with the coolant fluid and are discharged together to a mixing chamber that is used to condense pyrolysis gases.