| Abstract: | Rational utilisation high temperature materials in petrochemical furnaces While tubular furnaces in petrochemical industries were originally manufactured of cast materials, advantage is being taken now increasingly from wrought materials processed by hot deformation. These materials are characterized by a high degree of homogeneity and enable long tubular material to be obtained without transverse weld seams; in addition, they allow the use of additional specific alloying elements. In the EDC furnaces (ethylene-dichloroethylene) for the manufacture of vinyl chloride use is made of the high corrosion resistance of nickel alloys; these materials possess a remarkable resistance in chlorinated media, in particular at temperatures exceeding 600°C. Another property of importance in such conditions is the resistance to stress corrosion cracking produced by the formation of hydrogen chloride and chlorides. In the enthylene production furnaces operating at temperatures above 800°C steels are used with 32.5% Ni and 21% Cr; they resist carburazation and are creep resistant. These materials are also used for reforming furnaces and in particular for the catalyst tubes where high resistance to creep cracking is indispensable. |
