Top 10 Cleaning and Inspection Challenges: No. 1
Fired Heater Convection Section Cleaning: An Expert Analysis
In the vast and complex world of the refining industry, cleaning and inspection challenges are an everyday reality. As a globally recognized heat transfer efficiency recovery partner, Tube Tech has not only encountered these challenges at facilities worldwide but has also successfully resolved them. To shed light on the most pressing issues faced by the industry, we conducted a comprehensive survey of over 500 refinery operators. Based on the valuable feedback received, we have compiled this exclusive list of the Top 10 cleaning and inspection challenges faced by the refining and petrochemical sectors.
Coming in at number one, and the most prevalent cleaning challenge is fired heater convection section cleaning.
Introduction
Fired heaters, furnaces, and charge heaters are unable to operate effectively when they are fouled. Even a seemingly insignificant layer of dust measuring just 1mm, whether from atmospheric impurities or refractory deposits resulting from fuel system impurities or decoke effluent, can have detrimental effects on convection bank performance. This can lead to an increase in stack temperatures, ultimately resulting in higher energy consumption.
Traditionally, cleaning techniques have relied on using long hollow lances fed through side access doors to deliver cleaning mediums such as air, water jets, dry ice, or chemicals. However, these methods only clean the visible and reachable areas. Typically, only the top surface or underside of a single finned tube row is cleaned, which represents a mere 2% of the entire 2500 square meter surface area, leaving the majority untouched.
At Tube Tech we offer a finned tube air-side fouling cleaning system that ensures +90% surface contact of every finned or studded row in every bank. This system effectively cleans previously inaccessible convection banks within fired heaters, furnaces, charge heaters, and more.
The Challenge: Maintaining Efficiency and Extending Equipment Lifespan
Convection banks, often up to 60 feet in length, play a crucial role in the optimal functioning of industrial heaters. These banks have a finned or studded surface area of nearly 2500 square meters and ensure efficient heat transfer. However, without proper maintenance, they can exacerbate fouling and reduce performance.
Manual cleaning methods have their limitations. Despite the best efforts of operators, only approximately 10-15% of the total surface area can be reached, leaving a staggering 85% untouched and fouled. Even more intriguingly, some fired heaters have minimal access to the convection bank, with doors as small as 150mm x 200mm. Traditional techniques, such as manual water jetting, can worsen the problem by congealing refractory dust and pushing combustion deposits down into the lower, inaccessible rows. This solidifies the deposits into concrete-like formations, impeding heat transfer between finned tube rows.
Attempts to blast away fouling using abrasive media result in eroded tubes and blocked finned spaces, ultimately leading to higher fouling rates and deposition that becomes nearly impossible to remove. Soot blowers, meanwhile, can only remove soot within a narrow proximity, limiting their effectiveness. Foam cleaning, while suited for light dust deposits without bridging, fails to tackle the pervasive fouling found underneath and between convection bank rows, as it is only administered from the top.
Chemical cleaning methods, when implemented effectively, can provide desired results in removing hard deposits and preserving equipment longevity. However, care must be taken to choose solutions that minimize long-term damage and optimize cleaning efficiency. Additionally, leveraging advanced technologies and automation can revolutionize the maintenance process. By incorporating smart cleaning systems that work in synergy with flue gases and provide comprehensive coverage of the convection bank, industry professionals have access to a new era of effective and efficient cleaning.
Introducing Innovative Robotic Fired Heater Convection Bank Cleaning Technology
When it comes to addressing the challenges of limited access and deposit removal in fired heater convection banks, Tube Tech has developed a cutting-edge solution. Our state-of-the-art robot serves as a versatile delivery system, using a patented lance to penetrate deep between tube rows.
With meticulous precision, our robot delivers a targeted blast-cleaning radius, systematically eliminating deposits from every tube row. Its 360-degree external tube surface contact ensures thorough cleaning, without causing any damage to refractory or fiber blankets.
Installation of our robot is hassle-free, as it is placed on top of each convection bank through existing access doors. If necessary, new doors can be cut while the furnace is operational, reducing downtime and eliminating the need for shutdown periods. These doors can be as compact as 150 mm x 200 mm or as spacious as 24 in².
Equipped with remote cameras, the robot can be easily controlled by an operator outside the convection bank. The lance can be remotely activated, following technical drawings provided by the client to ensure comprehensive cleaning at every level. Once cleaning is completed, the robot conducts inspections and records cleanliness for archival and benchmarking purposes.
Rest assured, regardless of the convection bank’s pitch (square or triangular), our cleaning nozzles are designed to minimize the impact on the refractory, deflecting pressure off the tubes first to rapidly disperse. This eliminates the risk of refractory damage.