Abstract: The present invention relates to a combustion heater (100) for providing controlled heat (H) to an endothermic reaction process. The combustion heater comprises an integrated burner (20) to yield a hot burner exhaust gas (35) flow from burning a first fuel. The burner exhaust gas mixed with oxidant flows to a flue gas outlet along a flue gas flow path (FGP). Provided to the combustion chamber at a position outside a direct reach of flames from the burner is a secondary fuel conduit (30) with a plurality of nozzles (31) from which a second fuel (32) is transferred into a flow along the said flue gas flow path (FGP). The resulting combustion of the second fuel can be used to provide controlled heat to the to endothermic reaction operated in a reaction conduit (40) that is in thermal heat exchange with the combustion chamber.

Abstract: The invention relates to an ethylene plant, comprising a cracking furnace for converting a hydrocarbon feedstock into a cracked gas stream; a separation section to provide at least an ethylene-enriched product stream, a hydrogen-enriched fuel stream and a methane-enriched fuel stream from the cracked gas stream; a passage way for feeding at least part of the hydrogen-enriched fuel from the separation section to a burner of the cracking furnace and/or a passage way for feeding at least part of the hydrogen-enriched fuel from the separation section to a burner of a waste heat recovery boiler of a combined cycle gas turbine power plant(CCGT); a methane storage configured for storing methane-enriched fuel and a passage way for feeding at least part of the methane-enriched fuel from the separation section to the storage; the CCGT, comprising a gas turbine—comprising a combustor—and a passage way for feeding at least part of the methane-enriched fuel from the storage to the combustor of the gas turbine of the CC