Oil Refinery In The Netherlands Significantly Increases Preheat Train Up TimeUSE CASE
Oil & Gas
The Crude Distillation Unit 6 at this European oil refinery has two kerosene shell-and-tube heat exchangers purposed with recovering heat to reboil kerosene. They are 11 metres in length and experience a hard scaling precipitant on the process side and a sticky, polymerization fouling on the intermediate side.
In 2015, the Heat Transfer Engineering Team had only two options: Replace both bundles at significant procurement and downtime costs, or try something new. They opted to implement USP Technology, an Ultrasonic Clean-in-Place system.
The process team was able to extend heat exchanger run-time from 6-8 weeks to avoiding all cleaning for 3 years.
Heat Recovery Savings
Improvements in energy recovery and furnace efficiency led to annual savings of $1.4 million (USD) in the first year of service.
Duty Target Achieved
Initially hoping to achieve 6 MW Duty in this process, the Process Team was able to sustain 8 MW duty in the first year of service.
The Decision to Implement Ultrasonic Clean-In-Place Systems
Between 2006 to 2014, CDU reboilers were being cleaned in situ every 6-7 weeks by flushing the exchangers with gasoline, followed by high-velocity steam. In addition, an extensive mechanical cleaning was required every 1-2 years depending on opportunity crudes, operating changes, and other factors. During this time, the unit must be shut down for 10-16 days (and sometimes falling outside of a turnaround.)
The tubes were fouled with salt deposits, with 20% of tubes being completely blocked. On the shell-side, 50L of coke and sediment deposits from the crude were accumulating to form a troublesome sticky layer inhibiting energy recovery.
None of the chemical cleaning options tried were sufficient. After only 8 years of service, the process team was considering replacement of these 11m bundles altogether. In 2015, they decided to implement the Ultrasonic Clean-In-Place (CIP) system provided by Orange Ultrasonics, USP Technology.
CDU Reboiler E-214A with USP installed
CDU Reboiler E-214B with USP installed
Results: Mitigate Reboiler Fouling with Ultrasonic CIP
Ultrasonic Clean-In-Place (CIP) was able to generate substantial cost savings for this European Oil Major. Below is a graph collected by the refinery that measures Duty (MW) for this train. The green line illustrates performance from the train when the bundles were initially put into operation.
Only five years later, the Process Team was having difficulties maintaining their target 6 MW Duty, and minimum allowable Duty of 5 MW.
By implementing USP Technology after their 2015 turnaround, we have exceeded the 6 MW Duty benchmark, allowing the refiner to achieve 8 MW duty for the period measured and sustain greater than 6 MW Duty three years later.
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Results: Improve Reboiler Heat Transfer with Ultrasonic CIP
Similar to improving furnace efficiency, Ultrasonic Clean-In-Place (CIP) was able to improve Overall Heat Transfer Coefficient (OHTC) for this European Oil Major. Below is a graph collected by the refinery that measures OHTC for this train. The green line illustrates performance from the train when the bundles were initially put into operation, while the purple line shows performance 5 years later.
By implementing USP Technology after their 2015 turnaround, we can see that the OHTC levels with the technology installed are similar to that of the green line, the energy recovery obtained in the first year of this train’s operation.