The Challenge: Annual Pull-and-Clean on Crude Unit Exchangers
A leading Supermajor Refinery was experiencing routine fouling on two critical existing crude processing unit exchangers, a common and costly challenge. These piggyback exchangers each contained 198 SA-179 U-tubes (1″ OD, 17′ length) with the following –
Operating Conditions:
Tube Side: Crude oil (187°F to 295°F)
Shell Side: Heavy vacuum gas oil (HVGO) (350°F to 525°F)
both required annual cleaning, causing shutdowns that were:
- disrupting operations
- increasing maintenance costs
- reducing overall efficiency
- And shortening the exchangers life spans
The Solution: Curran’s Tube ID & OD Foul-Release Coatings
The client shipped both existing exchangers to Curran’s Houston facility, eliminating the need for field coating and minimizing our scope, which included surface preparation and application of our anti fouling coatings to the full length of the tube IDs, ODs, and tube sheets.
- Surface prep the full tube IDs and tube sheets
- Application of Curramix 3500 anti fouling coating (≤10 microns) to the ID of both exchangers
- Application of Curramix 2500 anti fouling coating on the OD of one exchanger for comparative analysis
The Result: First Time Skipping a Cleaning Cycle
A year after commissioning, the client shared its findings. Both exchangers were evaluated as part of their annual turnaround planning — and for the first time, the units:
- Skip a scheduled cleaning cycle
- Maintain acceptable pressure drop throughout extended operation
- Preserve heat transfer efficiency despite challenging process conditions
The coated IDs performed as intended, maintaining throughput and pressure drop within acceptable limits.
The exchanger with both ID and OD coatings showed significantly better exterior condition compared to the one with only ID coating.
In April 2025 the refinery’s lead process engineer shared:
“These are the first 2 bundles we coated in our crude process service. We pulled them this year as part of our Ready To Run (routine maintenance). We did not pull them last year due to acceptable performance (vs pulling and cleaning every year prior when they were uncoated).“
The visual inspection after operations prep showed exceptionally clean surfaces, particularly noteworthy given the challenging crude/HVGO service environment.
The engineer concluded: “This is a very clear win for you guys and a win for our site towards the goal of ‘doing maintenance less’.”
Key Takeaways — minimal fouling observed:
- The coated IDs performed as intended, maintaining throughput and pressure drop within acceptable limits.
- The exchanger with both ID and OD coatings showed noticeably better exterior condition than the one with only ID coated.
- Site personnel confirmed this was a milestone: the first maintenance cycle successfully deferred due to coating performance.
Business Impact
The Supermajor Refinery experienced multiple benefits from Curran’s coating solution:
- Extended Runtime: Eliminated an entire cleaning cycle with exchangers performing acceptably for twice as long
- Reduced Maintenance: Decreased labor, materials, and equipment costs associated with annual cleanings
- Operational Continuity: Fewer shutdowns meant more consistent production
- Visual Confirmation: Post-inspection revealed significantly reduced fouling compared to historical performance
- Strategic Alignment: Supported the refinery’s corporate initiative of “doing maintenance less”
Why It Worked
This success demonstrates the value of Curran International’s approach:
- Process-specific coating selection based on actual operating conditions
- Technical surface preparation ensuring proper adhesion
- Controlled shop environment for optimal application
- Comprehensive documentation giving the client confidence in coating integrity
This case study demonstrates how strategic coating applications can transform maintenance practices in refinery operations, turning an annual pain point into a sustainable fouling management solution.
Who We Are
At Curran International, we are the industry leader in Anti-Fouling and Corrosion Tube ID and OD Heat Exchanger coatings with expertise and resources to help refineries around the world directly improve heat transfer, extend run time, and reduce maintenance frequency in all your critical heat transfer equipment.
Are you ready to achieve similar results?
Click Here to learn more about the application process and the data behind our successful coating applications.