Metallic furnace tube for electrically heated cracking furnace, and electrically heated cracking furnace and cracking method

Abstract

This invention belongs to the field of pyrolysis, and relates to a metal furnace tube for an electrically heated pyrolysis furnace, the furnace itself, and a pyrolysis method. The metal furnace tube is made of FeCrAl alloy, with the following composition: Cr 10-30wt%, Al 2-8wt%, Mo 0-7wt%, C 0-0.5wt%, Mn 0-1wt%, Si 0-3wt%, and the balance being Fe. The pyrolysis furnace includes a preheating section, a pyrolysis section, and subsequent units; each of the preheating and pyrolysis sections is independently equipped with an electric heating system; the metal furnace tubes of the preheating and pyrolysis sections serve as electric heating conductors; temperature sensors are installed on the inner wall of the metal furnace tubes, and ground wires are installed at the inlet and outlet; the electrodes are located on the outer walls at both ends of the preheating and pyrolysis sections. After high-temperature oxidation, the metal furnace tube of this invention can produce an alumina coating on its inner surface, reducing coking during the pyrolysis process and further improving the operating cycle.

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