Abstract: A device for indirectly heating fluids, particularly for high temperature processes, includes a heating space in which at least one tube coil is arranged. The tube coil is constructed in a planar manner and the fluid to be heated can be conducted through the tube coil. Heat radiators act from the outside on the tube coil. The heat radiators have a heat radiation surface shaped corresponding to the planar extension of the tube coil. The heat radiators are arranged on opposite sides of the tube coil. Longitudinal ribs are provided on two opposite sides of the tube of the tube coil with respect to the tube cross section.

Abstract: Apparatus for providing heat to a reaction chamber in which an endothermic reaction is performed under utilization of hot smoke gas includes a barrier, preferably a tubular barrier at least partially enclosing the reaction chamber but being spaced therefrom; hot smoke gas is fed to a ring chamber outside of the barrier and caused to flow there along while losing some of its heat content until at a lower end of the barrier the flow of the cooled smoke gas is reversed and the gas is introduced into a gap between the barrier and the reaction chamber so that heat is transferred through the barrier from the hot smoke gas as it flows along the outside of the barrier to the gas as it flows in the gap for heating the reaction chamber in an essentially uniform manner.

Abstract: A stream of process gas is indirectly heated in an elongated reaction chamber (1) with a longitudinal axis, a first end (12) and a second end (13) and defined by an outside shell (2) and a thermally conductive inner wall (4). The inner wall defines at least one recess or cavity (3) which extends substantially between the first and second end of the chamber and parallel to the longitudinal axis thereof. A process feed line (6) and a product-gas discharge line (7) are provided at opposite ends (12, 13) of the chamber. A heat conductive and heat resistant barrier (8) which defines an interior space extends coaxially with the recess or cavity (3) substantially along the entire length of the inner wall (4) and forms an annular space (9) therewith. A hot flue gas feed line (10) and a flue gas discharge line (11) is provided at one end (13) of the chamber.