A flow reactor for photochemical reactions comprises an extended flow passage (20) surrounded by one or more flow passage walls (22), the flow passage having a length and a light diffusing rod (30) having a diameter of at least 500 m and a length, with at least a portion of the length of the rod (30) extending inside of and along the flow passage (20) for at least a portion of the length of the flow passage (20).

This monolithic reactor is an adaptable and scalable, flow-through reaction containment apparatus embodied as a one-piece monolithic block of material that retains re-configurability to improve reaction processing. This apparatus increases operational flexibility, adaptable design, and vastly simplifies construction of tubular reaction-containment configurations. Internally, the monolithic block comprises one or more closely spaced, functional voids which operate as fluid channels that can be configured in various geometric arrangements. The apparatus is widely scalable, provides high thermodynamic efficiency, manufacturing simplicity, and affordability for varied operations through additive manufacturing, and has a compact physical footprint.

A multi-structured tubular element for producing a reactor for effecting exothermic/endothermic chemical reactions, comprises two or more monolithic thermoconductive bodies, assembled together so that each has a part of the side surface interfaced with the side surface of one or more monolithic thermoconductive bodies adjacent thereto, so as to form as a whole, a honeycomb structure containing a plurality of longitudinal channels extending from one end to the other of said tubular element, suitable for being filled with a granular catalytic solid.

A flow reactor for photochemical reactions comprises an extended flow passage (20) surrounded by one or more flow passage walls (22), the flow passage having a length and a light diffusing rod (30) having a diameter of at least 500 m and a length, with at least a portion of the length of the rod (30) extending inside of and along the flow passage (20) for at least a portion of the length of the flow passage (20).