NOVELTY - The furnace (30) has a fuel inlet (34) connected to a burner (32). An air supply nozzle (35) is formed in a furnace end (31) of an opposite side of the fuel inlet to supply air to the furnace body along implant and opposite directions. A heat exchanger (33) delivers heat to a combustion unit. The burner is installed in another furnace end, and burns fuel in an inner side of the combustion unit. An air feed unit is provided with an air pump for injecting air through the air supply nozzle. An air feed unit is provided with an air pump for injecting air through the air supply nozzle.    USE - Backward direction air injection technology based flameless combustion industrial furnace for a backward direction gas recirculation system and a fuel cell system (all claimed).    ADVANTAGE - The furnace injects air along backward direction so as to uniformly distribute temperature within a combustion chamber, thus reducing production of incomplete combustion material and nitrogen-oxide and improving combustion efficiency. The furnace induces strong turbulent flow in the air jet nozzle at high-speed and improves durability of a backward direction gas recirculation system. The furnace stabilizes emission quantity reaction and improves carbon monoxide reduction effect so as to improve driving performance of the backward direction gas recirculation system. The furnace reduces emission quantity of carbon monoxide and nitrogen oxide and exhaustion of pollution element. The furnace reduces cyclical replacement of catalyst by using a non-catalytic fuel reformer along high speed backward direction so as to reduce management cost. The furnace improves gas recirculation and thermal gravity and achieves equalization of temperature and chemical reaction. The furnace reduces heat evaporation loss due to smooth hydration of catalytic without producing carbon.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a fuel cell system    (2) a backward direction gas recirculation system.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a backward direction air injection technology based flameless combustion industrial furnace.    Backward direction air injection technology based flameless combustion industrial furnace (30)    Furnace end (31)    Burner (32)    Heat exchanger (33)    Fuel inlet (34)    Air supply nozzle (35)