NOVELTY - The chemical reactor system (100) comprises a first reaction zone (110), a heat path positioned to direct heat into the first reaction zone, a reactant source coupled to the first reaction zone, a first actuator coupled in fluid communication with the first reaction zone to cyclically pressurize the first reaction zone, a second reaction zone positioned in fluid communication with the first reaction zone, a mechanism coupled between the first and second reaction zones to control a flow rate between the first and second reaction zones, and a second actuator.    USE - The chemical reactor system is useful for producing hydrogen-based fuels and structural elements from feedstocks, and producing structural building blocks from carbon and/or other elements that are released when forming the hydrogen-based fuels.    ADVANTAGE - The chemical reactor system is capable of economically, rapidly, energy-efficiently producing the clean-burning, hydrogen-based fuels and/or the building block constituents with high quality and viability and without environmental degradation and health impacts, and allows to effectively recycle carbon and/or other constituents for compatible production of durable goods.    DETAILED DESCRIPTION - The chemical reactor system (100) comprises a first reaction zone (110), a heat path positioned to direct heat into the first reaction zone, a reactant source coupled to the first reaction zone, a first actuator coupled in fluid communication with the first reaction zone to cyclically pressurize the first reaction zone, a second reaction zone positioned in fluid communication with the first reaction zone, a mechanism coupled between the first and second reaction zones to control a flow rate between the first and second reaction zones, a second actuator coupled in fluid communication with the second reaction zone to cyclically pressurize the second reaction zone, a first heat exchanger positioned to direct heat from a first product leaving the first reaction zone to a reactant entering the first reaction zone, a second heat exchanger positioned to direct heat from a second product leaving the second reaction zone to the reactant entering the first reaction zone, a controller coupled to the first and second actuators, a solar collector positioned to direct solar radiation through a reactor surface of the heat path, where the reactor surface is transmissive to solar energy, and a secondary heat source coupled to the first reaction zone. The chemical reactor system further comprises a first reactor portion having a first reactant port, a first product port and a solar radiation path positioned to direct solar radiation into the first reaction zone, a source of methane and carbon dioxide coupled to the first reactant port, a second reactor portion having a second reactant port coupled to the first product port, a second product port and a second reaction zone (120) positioned in fluid communication with the second reactant port and the second product port, a source of hydrogen coupled to the second reaction zone, and a solar concentrator (103) positioned to direct solar radiation along the solar radiation path. The mechanism includes check valve positioned in fluid communication with the first and second reaction zones and positioned to admit the first product into the second reaction zone when the pressure in the first reaction zone is greater than the pressure in the second reaction zone, and prevents fluid communication between the first and second reaction zones when the pressure in the second reaction zone is greater than the pressure in the first reaction zone. The controller is programmed with instructions that: control the first and second actuators in a coordinated manner based in part on a flow rate of the second product from the second reaction zone when the program is executed; direct first and second actuators to cyclically pressurize the first reaction zone when the program is executed; and activate the actuators to increase a rate of methanol production based on an input corresponding to the rate of methanol production when the program is executed, and is operatively coupled to the first and second actuators and the secondary heat source to activate the secondary heat source in response to an indication of low solar input to the first reaction zone. The first heat exchanger is positioned in fluid communication with the first and second reaction zones, the first product port and second reactant port, and has a first flow path positioned to direct products from the first reaction zone and the first reactor into the second reaction zone and the second reactor and a second flow path that is positioned in thermal communication with the first flow path and coupled between the reactant source and the first reaction zone and between the first reactant port and the source of methane and carbon dioxide. The second heat exchanger is positioned in fluid communication with the second reaction zone and the second product port, and has a third flow path positioned to direct products from the second reactor and a fourth flow path positioned in thermal communication with the second flow path and the third flow path and coupled between the reactant source and the first reaction zone and between the first reactant port and the source of methane and carbon dioxide. The first reaction zone is positioned in fluid communication with the first reactant port and the first product port. The first actuator is coupled in fluid communication with the first reactant port to cyclically pressurize the methane and carbon dioxide. An INDEPENDENT CLAIM is included for a method of processing a hydrogenous compound.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic partial cross-sectional view of a solar-heated reactor vessel.    Chemical reactor system (100)    Reactor vessel (101)    Solar concentrator (103)    First reaction zone (110)    Second reaction zone. (120)