Top 10 Cleaning and Inspection Challenges: No. 2
Texas Tower /VCFE (Vertical Combined Feed Exchanger) Cleaning: Enhancing Downstream CCR Platformer Performance
The refining industry is vast and complex, presenting numerous cleaning and inspection challenges. As a globally recognized partner for heat transfer efficiency recovery, IGS Tube Tech has not only encountered these challenges at facilities worldwide but has also effectively resolved them. To shed light on the most pressing issues faced by the industry, we conducted an extensive survey of over 500 refinery operators. Based on their valuable feedback, we have compiled an exclusive list of the Top 10 cleaning and inspection challenges encountered by the refining and petrochemical sectors.
At the core of many refineries lies a crucial component known as the VCFE, or vertical combined feed exchanger, commonly referred to as a Texas Tower. Originally envisioned with a small footprint and minimal fouling potential, this colossal shell and tube exchanger has become the focus in the pursuit of increased megawatt recovery and productivity.
Surprisingly, the lack of foresight regarding fouling issues during the design phase has resulted in accessibility and cleanability becoming critical concerns for these vast heat exchangers. Ensuring the integrity of these assets becomes even more imperative, as insufficient cleaning for eddy current or IRIS tube inspection can have severe financial repercussions on a refinery’s bottom line.
Tube Tech is uniquely positioned to address this challenge. Using cutting-edge technologies and methods, we offer comprehensive cleaning and inspection services for all shell and tube Texas Towers, as well as other floating head and welded exchangers. Our innovative approach allows us to complete the task in a fraction of the time compared to traditional high-pressure water blasting or chemical methods.
The Challenges and Symptoms of Texas Tower Underperformance
1: Temperature Variations Indicate Cleaning Needs
One of the initial symptoms that signal the requirement for cleaning a Texas Tower is the fluctuation in reactor outlet and heater inlet temperatures. These variations serve as a crucial indicator that the shell and tube side of the tower require maintenance. ∆P across the tubes is a good indicator of tube side fouling. Typically, Texas Towers are designed with a 20% over capacity, therefore the performance drop is only noticed once that 20% has diminished. This can then lead to a faster decrease in performance.
2: Overcoming Obstacles in Tube Cleaning
The first challenge faced by high-pressure water jetting and chemical cleaning contractors is the unblocking and cleaning of the unusually small tube diameter of 12mm (0.5 inch), combined with a vertical tube length of over 20 meters (65ft).
3: Tackling Shell Side Fouling
Negotiating the external shell side presents the most daunting hurdle as it requires removing tube surface fouling deeply embedded within the bundle. Accessing this fouling is only possible through the narrow 6mm (1/4 inch) spaces between the tubes, posing a significant challenge to maintenance personnel.
4: The Compound Effect of Chemical Cleaning
Moderate to heavy fouling poses further complications when chemical cleaning methods are employed. The pumped fluids lack the necessary shear force to effectively dislodge and flush the dense and often inert mixture of hydrocarbons, coke, iron oxide, and gum formation. Unless there is passage through the tubes, the chemicals will simply sit on top of the blockage and not penetrate. Sometimes the use of chemicals causes more fouling issues, as it is very difficult to select the correct chemical.
Overcoming Issues: Tube Cleaning and Inspection Solution for Improved Production Standards
To address a range of challenges and ensure optimal performance, obtaining access to reliable cleaning and inspection services is crucial. At Tube Tech, we offer a tailored and advanced cleaning solution for tube and shell-side systems, guaranteeing the restoration of VCFEs to production standards. Our comprehensive range of tube cleaning and shell side cleaning techniques and technologies includes:
Tube-side Cleaning Techniques:
- Utilization of pulse jets to identify and unblock soft tube blockages.
- Efficient removal of severe tube blockages through the application of multiple safedrill units.
- Application of rapid rotary turbine and tube cleaning darTTs™ for effective tube descaling.
Shell-side Cleaning Techniques:
- Tube Tech’s revolutionary lance system employs high pressure, low volume water jets, to eliminate shell-side fouling, irrespective of its severity. Our system can slide into the narrow 6mm tube space, making it a versatile choice.
Conclusion
The Texas Tower/ VCFE is a crucial component often unnoticed in many refineries. However, it requires regular cleaning, in some cases every four years to maintain optimal performance, especially during refinery expansions or in cases of process carry-over, such as catalyst or oil.
When the time comes for cleaning these assets, it is important to choose a contractor who guarantees a thorough cleaning of both the tube and shell sides. Tube Tech is proud to be recognized as the leading authority in in-situ VCFE cleaning.
We recently received accolades from a refinery client based in the Netherlands, stating, “Asset integrity is of utmost importance to refinery operators, and we were delighted with the excellent service provided within the specified timeframe.”
Texas Tower / VCFE cleaning forms a part of the wide range of IGS services offered to improve and maintain the efficient operation of Catalytic Reformers, such as UOP Platforming CCRs, etc. Cetek High Emissivity Ceramic Coatings enhance radiant heat transfer efficiency up to 15% in fired heaters, resulting in significant productivity benefits and environmental emissions reduction. Hot-tek unique online maintenance and inspection services provide solutions to situations that would otherwise lead to expensive unplanned and emergency shutdowns.