(135b) Ethylene Decomposition from Heat of Compression in Small Volume Piping

Ethylene decomposition is a known process safety concern in high purity, high pressure ethylene services. Ethylene decomposition can be initiated by various mechanisms with one mechanism being the adiabatic compression of diatomic gases by high pressure ethylene.

This presentation will summarize a 2020 near miss event at the Beaumont Chemical Plant where a carbon blockage at the inlet to an ethylene product relief valve was identified during a relief valve maintenance task. As part of the investigation, it was determined that a relatively small volume of piping can be susceptible to an ethylene decomposition reaction in the presence of oxygen and nitrogen.

This presentation will provide a broad overview of ethylene decomposition fundamentals, an incident summary and suggest mitigation ideas to address this process safety risk.