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Behavior of Delayed Coker Heater Tubes – Our Experience

Presented By

Shaileshkumar Oza - Reliance Industries Limited


Courtesy of RILCoker unit of Reliance Industries Limited, Jamnagar-Gujarat DTA Refinery was commissioned in Year 1999. In Coker furnaces, a gradual thickness loss from inner wall has been observed in radiant section tubes of the heater coils. Scrapper pigging is being carried out periodically for removal of adhered coke deposit inside the coils in radiant section tubes. Inspection has revealed a significant thickness loss in alloy steel tubes over a period of time. The thickness loss was mainly attributed removal of the protective sulphide layer (formed due to high temperature sulphidation) by scrapper pigging and exposing fresh surface for sulphidation and corrosion. Based on the experience, an in-house strategy has been developed to ensure reliability of heater tubes in DTA refinery coker. This paper discuss the cause of heater tube thickness deterioration, inspection strategy for heater coils, systematic approach for procurement of spare tubes, replacement methodology of tubes considering optimal coil replacement program within the planned outage without compromising on integrity and resource planning.

This document also outlines the other parallel approaches like conventional API RP 530 calculation and Fitness for Service assessment that has been adopted to decide the retiring thickness criterion for coker furnace coils.

Shailesh Oza - RILShailesh Oza is the General Manager and the Head of Corrosion and Inspection at DTA Refinery in Jamnagar for Reliance Industries Limited. He is responsible for ensuring reliability and integrity of Static equipment at the Refinery. Shailesh specializes in the inspection of static equipment, risk based inspection management, advanced non-destructive testing, welding and corrosion management, and root cause analysis of critical failures.

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