NOVELTY - System comprises a copper-chlorine cycle, a carbon dioxide capture loop, and a hydrogenation cycle, which are integrated.    USE - The system is useful for hydrogen production, carbon dioxide capture and production of carbon based compounds including carbon monoxide, methane, methanol, dimethyl ether, gasoline, synthetic hydrocarbons, derivatives of methanol, and formic acid. The two-stage fluidized/packed bed reactor is useful for copper(II) chloride hydrolysis, copper(II) chloride drying and dehydration processes of a copper-chlorine, and for carbon dioxide absorption and oxygen production with chloride in a magnesium-chlorine-sodium/potassium cycle. The hybrid two-stage spray-fluidized/packed bed reactor is useful for simultaneous copper(II) chloride drying in a copper-chloride cycle in the spray drying chamber and carbon dioxide absorption in a fluidized/packed bed chamber, and for carbonation of sodium hydroxide for the capture of carbon dioxide in the magnesium-chlorine-sodium/potassium-carbon dioxide cycle. The two-stage wet-mode absorber is useful as a scrubber system and/or carbon dioxide absorption unit. The hybrid two-stage absorber is useful for undesirable gas and/or particulate scrubbing and/or carbon dioxide absorption. The catalyst packed/fluidized bed reactor is useful for hydrogenation of carbon dioxide to produce methanol, methane, carbon monoxide or their derivatives (all claimed).    ADVANTAGE - The system is capable of reliably, safely and economically producing the carbon based compounds with high efficiency and quality.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a two-stage fluidized/packed bed reactor comprising a main body defining an inlet for allowing fluidization gases to enter the reactor and an outlet for allowing fluidization gases to exit the reactor, and at least two separate chambers defined by the main body providing two respective fluidization zones, each of the two chambers defining a respective inlet for feeding solid reactants in the chambers and a respective outlet providing an exit for solid reactants from the outlet;    (2) a hybrid two-stage spray-fluidized/packed bed reactor comprising a main reactor body defining a bottom providing for carbon dioxide-containing gas to enter the main reactor body and a top portion providing for gas to exit from the main reactor body, a fluidized/packed bed positioned within the main reactor body for absorbing carbon dioxide and water vapor prior to the gas exiting from the top portion, and a spray nozzle for spraying droplets against the current of the incoming carbon dioxide-containing gas;    (3) a two-stage wet-mode absorber that serves as a scrubber system and/or carbon dioxide absorption unit, comprising a lower chamber having a bottom section for gas flow to enter and move upwardly to a top section, an inlet for liquid absorption solution to enter and progressively flow downwardly in the inlet thus allowing upwardly flowing incoming gas to mix with the downwardly flowing absorption solution, and an outlet for allowing absorbed gas to exit, and an upper chamber positioned above the lower chamber defining a bottom section comprising gas inlets for providing fluid communication with the lower chamber thus providing for residual gas from the lower chamber to flow upwardly to a top section comprising a gas outlet for gas to exit out of the absorber, an inlet for an inlet for liquid absorption solution to enter and progressively flow downwardly in the inlet thus allowing upwardly flowing incoming gas to mix with the downwardly flowing absorption solution, and an outlet for allowing absorbed gas to exit the reactor;    (4) a hybrid two-stage absorber comprising a first stage with a liquid solution for wet method absorption of gases, and a second stage with packed bed of solid sorbents to absorb carbon dioxide from a gas stream or completely absorb gases not absorbed by the wet method in the first stage; and    (5) a catalyst packed/fluidized bed reactor comprising a lower mixing chamber, one or more inlets for allowing hydrogen and carbon dioxide to enter the mixing chamber, an upper packed/fluidized bed zone filled with catalyst particles or structures for receiving the hydrogen and carbon dioxide mixture from the lower mixing chamber via gas channels, a double-chamber in fluid communication with the upper packed/fluidized bed zone to discharge spent solid catalysts and a top outlet providing products produced by the reactor to exit from the top outlet.