Generation of quasi-multilayered shells in the process of operation of coiled pipes in a furnace used for pyrolysis of hydrocarbons | Mekhanika | kompozitsionnykh | materialov i konstruktsii
> Volume 10 > №2 / 2004 / Pages: 153-165

Generation of quasi-multilayered shells in the process of operation of coiled pipes in a furnace used for pyrolysis of hydrocarbons

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Abstract:

In practice, coiled pipes working under extreme conditions in furnaces for pyrolysis of hydrocarbons may have all types of defects of various natures. These defects may stimulate generation of cracks. A distinctive feature of the process of pyrolysis is accumulation of by-product, coke. This deposition of coke at the inner surfaces of pipes is the reason of aggressive diffusion of carbon into wall’s structural material, high-alloy steel. Due to the technology of pyrolysis, structural material works under high temperature up to 1000o C. At that, the thicker a layer of the coke at the inner surface of a pipe, the higher the temperature required. High temperature results in decarbonization of the external surface of pipes and intensive generation of pores that are corresponded to the creep mode. As a result, we arrive at quasi-multilayered shells and properties of these layers differ drastically.

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