Abstract: A reaction tube system of a steam reformer, more generally referred to as tubular cracking furnace, for the indirect heating of cracking feedstock, such as the catalytic cracking of hydrocarbons, includes a plurality of reaction tubes and headers, the reaction tubes penetrating through the bottom of the steam reformer and being extended to the associated header by low-alloy tube sections attached to the tubes by circumferential welds. The reaction tubes are surrounded in the area of the weld(s) by a coaxial protective tube having one open end and defining a free annular space around the reaction tube. The protective tube prevents deterioration by corrosion of the weld(s) joining the tube sections of high-alloy steel with low-alloy extension sections with unalloyed steel extension section.

Abstract: The invention relates to an apparatus for lining the inner walls of industrial furnaces with a plurality of insulating blocks, each block comprising an insulating mat which is folded in corrugated manner and possibly stitched in this shape, the insulating mats being made of highly heat-resistant material, especially ceramic fibrous material, with carrying elements arranged on the outside of the corrugations, the carrying elements being equipped on the outside of the insulating blocks with fixing means to allow each individual insulating block to be fixed to the furnace wall.