Flameless combustion burner for an endothermic reaction process

A combustion heater for providing controlled heat to an endothermic reaction process, the combustion heater comprising a combustion chamber including:

• a primary combustion zone including a burner for burning a first fuel from a first fuel inlet with an oxidant from an oxidant inlet to yield a hot burner exhaust gas;
• a flue gas outlet;
• and a flue gas flow path from the burner to the flue gas outlet;
• a secondary fuel conduit having a second fuel inlet and provided with a plurality of fuel nozzles for transferring a second fuel from the secondary fuel conduit into the combustion chamber, the nozzles distributed along a length of the secondary fuel conduit and opening into the combustion chamber at a location along the flue gas flow path, to define a secondary combustion zone, separate from the primary combustion zone, for generating heat from combustion of the secondary fuel in a secondary combustion, wherein the secondary fuel conduit is located outside a direct reach of flames from the burner, when in use, and wherein the secondary fuel conduit has an integrated cooling circuit with a coolant inlet for a coolant;
• a reaction conduit for a reactant and a product of the endothermic reaction process, the reaction conduit comprising a reactant feed inlet and a process effluent outlet, the reaction conduit providing a process flow path between the reactant feed inlet and the process effluent outlet, wherein the reaction conduit along at least part of the process flow path is in thermal heat exchange with the combustion chamber at a location along the secondary fuel conduit;
• and
• a sleeve barrier positioned between the reaction conduit and an outer wall of the combustion chamber to define a comparatively narrow flue gas flow path between the sleeve barrier and the reaction conduit within a comparatively wider volume of the combustion chamber.