Systems and methods for producing product gas fuel and solid char fuel from a carbon-containing feedstock are described. Feedstock is introduced into and transported through at least one substantially horizontal sublimation reaction chamber. An initial and final sublimation temperature is maintained within less than 10 C. in an atmosphere free from external oxygen and externally supplied catalyst. The system is configured to not have any product gas leak out of the reaction chamber or oxygen leak into a hot box configured to heat the reaction chamber.

A shale pyrolysis system includes a retort with a first side and a second side. The second side is opposite the first side and the first side and the second side include descending angled surfaces at alternating angles to produce zig-zag motion of shale descending through the retort. Corners of the retort that change direction of the shale are rounded. The system includes steam distributors coupled to the first side and collectors coupled to the second side to produce crossflow of steam and heat across the descending shale from the first side to the second side, and a steam temperature control subsystem coupled to the steam distributors and configured to deliver higher-temperature steam to one or more upper sections of the retort and lower-temperature steam to one or more lower sections of the retort.

A shale pyrolysis system includes a retort with a first side and a second side. The second side is opposite the first side and the first side and the second side include descending angled surfaces at alternating angles to produce zig-zag motion of shale descending through the retort. Corners of the retort that change direction of the shale are rounded. The system includes steam distributors coupled to the first side and collectors coupled to the second side to produce crossflow of steam and heat across the descending shale from the first side to the second side, and a steam temperature control subsystem coupled to the steam distributors and configured to deliver higher-temperature steam to one or more upper sections of the retort and lower-temperature steam to one or more lower sections of the retort.

A shale pyrolysis system includes a retort with a first side and a second side. The second side is opposite the first side and the first side and the second side include descending angled surfaces at alternating angles to produce zig-zag motion of shale descending through the retort.

Corners of the retort that change direction of the shale are rounded. The system includes steam distributors coupled to the first side and collectors coupled to the second side to produce crossflow of steam and heat across the descending shale from the first side to the second side, and a steam temperature control subsystem coupled to the steam distributors and configured to deliver higher-temperature steam to one or more upper sections of the retort and lower-temperature steam to one or more lower sections of the retort.

A shale pyrolysis system includes a retort with a first side and a second side. The second side is opposite the first side and the first side and the second side include descending angled surfaces at alternating angles to produce zig-zag motion of shale descending through the retort.

Corners of the retort that change direction of the shale are rounded. The system includes steam distributors coupled to the first side and collectors coupled to the second side to produce crossflow of steam and heat across the descending shale from the first side to the second side, and a steam temperature control subsystem coupled to the steam distributors and configured to deliver higher-temperature steam to one or more upper sections of the retort and lower-temperature steam to one or more lower sections of the retort.