Chevron Chemical Company LLC

Charles D. Buscemi

John V. Heyse

Charles D Buscemi

John V Heyse

A method of protecting carbon and low-alloy steels from high temperature hydrogen attack. A carbon or low-alloy steel portion of a reactor system that is to be contacted with high pressure hydrogen at elevated temperatures is provided with an intermetallic, diffusion barrier layer that reduces the rate of hydrogen attack at least ten-fold compared to the steel portion without the diffusion barrier layer.

Diffusion barriers for preventing high temperature hydrogen attack

A hydrocarbon conversion process wherein austenitic stainless steel portions that are subject to halide stress-corrosion cracking conditions, such as the colder portions of the process equipment including effluent coolers, knockout drums, accumulation drums, and piping low points, are provided with a protective layer having improved halide stress-corrosion cracking resistance. The method comprises applying a metal cladding, plating, paint or other coating to a stressed portion of austenitic stainless steel hydrocarbon conversion process equipment, optionally curing the coated steel to form intermetallic compounds to protect the steel portions; converting hydrocarbons utilizing a halided catalyst or under conditions where a halogen-containing compound is added or evolved or both; and subjecting the protected steel portion to halide stress-corrosion cracking conditions. A preferred coating material comprises tin, and preferably one or more intermetallic layers are provided to at least a portion of an austenitic stainless steel substrate to improve its stress-corrosion cracking resistance.

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San Francisco, CA, United States of America

Charles D Buscemi