The convection section of an SMR is made of tubes where flue gases transfer heat to process fluids (steam, feed, etc.). Over time, these tubes accumulate soot, refractory particles, and other deposits. This fouling acts as insulation, hindering heat transfer, raising flue gas temperatures, and forcing the reformer to consume more fuel to maintain the required process temperatures and hydrogen production.

Traditional cleaning methods for convection sections are labor-intensive, often requiring confined space entry and exposing the asset to potential refractory damage. Robotic cleaning, utilizing specialized ROVs, offers a safer and more efficient alternative. The refinery partnered with IGS Tube Tech, a leader in ROV cleaning solutions, to implement this technology.

1. Inspection: A visual inspection using cameras mounted on the ROV assessed the extent and type of fouling within the convection section.
2. ROV Programming: Based on the inspection, an appropriate cleaning strategy was developed and the ROV system was programmed by Tube Tech operatives.
3. Cleaning Operation: The ROV was inserted into the convection section. The operator remotely controlled the ROV’s movement through the tube bundles and cleaned the convention banks.
4. Verification: A final inspection confirmed the effectiveness of the cleaning and ensured all fouling was removed.

Post-cleaning, the SMR experienced a notable transformation:

• Less Hydrogen Production Costs: The improved heat transfer led to a 2.6% cost reduction per nm³ of H₂.
• Steam Production Gain: After cleaning, the refinery produced 20% more steam in the convection section with the same hydrogen yield. Moreover, superheated steam temperature was 10 °C higher than before cleaning.
• Enhanced Thermal Efficiency: The SMR now requires less fuel to achieve the same output, resulting in significant cost savings. Total fuel efficiency gain was ca. 3%.
• Reduced Flue Gas Temperature: Cleaner tubes facilitated more efficient heat transfer, lowering flue gas temperature leaving convection section by 58 °C.

• Minimal Downtime: The cleaning was performed during scheduled maintenance, minimizing production loss.
• Enhanced Safety: ROV cleaning eliminates the need for human entry into confined spaces, reducing safety risks.
• Extended Equipment Lifespan: Regular cleaning prevents corrosion and extends the life of the SMR’s convection section.