A Historical Integrity Assessment of a Refinery Fired Heater - A Case Study

Introduction

Minimizing unplanned shutdowns due to outages of process equipment is of paramount importance for operators in terms of costs and efficiency. Achieving continuous heater reliability, optimum performance, and heater productivity to prevent unplanned shutdowns can be very challenging since heater operation and heater demand may constantly change. Thus, to ensure continued reliability, a robust and comprehensive strategy based on current industry best practices should be in place to mitigate such occurrences. Strategies may be based on historical performance data together with historical repair, inspection and maintenance practices, data, and procedures. However, each individual heater is unique to its environment and operational demand based on operational necessity. As such, individual strategies should therefore be in place and/or formulated for a more proactive and tailored approach towards heater health monitoring and improved heater reliability.

Whatever strategy is developed and/or tailored for individual heaters, it should include an assessment and/or an enhancement of the following:

• The continuous monitoring of online data, such as process operating parameters from integrity operating windows (IOWs) and data from the laboratory information management system (LIMS).
• Any major deviation of set parameters should be investigated to understand and ascertain any potential impact. This may include the development of a database and the use of predictive tools to assess and predict future scenarios affecting integrity based on historical process data.
• Remaining life assessments and/or fitness-for-service assessments based on observed damage or degradation mechanisms in accordance with API 530, API 573, and API 579-1 ^[1-3].
• By knowing the remaining life and addressing issues proactively, catastrophic failures may be prevented by knowing when components should be repaired and/or replaced. Maintenance and inspection intervals can also be planned in a timelier manner, thereby reducing the costs associated with unplanned shutdowns.
• Failure investigation analysis of components that have failed under normal service operating conditions to establish the root cause(s).
• Methodologies ranging from those as given by API 585 to Root Cause Analysis incorporating laboratory-based failure analysis of components utilizing scanning electron microscopy and energy dispersive x-ray analysis are a staple for the industry for establishing the root cause of a failure ^[4]. Such investigations should provide corrective actions and recommendations to prevent any recurrence.

Incorporating the above elements into the formulation of a strategy to manage and maintain the integrity of fired heaters is no small feat, but is critical to the successful operation and performance of a refinery. Many facilities already operate with these elements built into their operating philosophies, but with mixed results. In such cases, further effort needs to be made by strengthening the elements through confirming and tightening the control of critical parameters and improving the accuracy of the input data to prevent deviations. Only then can performance be optimized and reliability improved.