Reactor for steam reforming of hydrocarbons with heat exchange

Method for steam reforming of hydrocarbons in a gas- heated reforming reactor, in which a process gas flow comprising steam and hydrocarbons is sent under steam reforming conditions through a steam reforming catalyser bed in indirect heat exchange with an externally produced hot gas and in which the process gas flow is led through a first catalyser bed 24 divided within a first cylindrical chamber 14 in the form of a coiled panel with walls 15, which delimit between themselves a helical space and are rolled in the upper part of the reactor 10 around the vertical axis I of the reactor 10; and the hot gas is introduced into the lower part of the reactor 10 and sent in one flow direction through the reactor and through passages 13 between the walls 15 of the chamber 14 in indirect heat contact with the process gas flow, which flows through the chamber 14.