Author: Mike Watson, Managing Director, Tube Tech

Following a recent survey of refinery operators from across the world Tube Tech have compiled the Top 10 cleaning and inspection challenges faced by the refining industry.
As a world leading specialist industrial cleaning contractor Tube Tech have solved some of the refining and petrochemical sectors most difficult cleaning challenges. Tube Tech asked over 2500 refinery operators to complete their survey and the Top 10 cleaning and inspection challenges were developed as result of the survey feedback.
Below is the 9th most common cleaning and inspection challenge faced by the refining sector.

Ethylene Cracking Furnace Cleaning

As they represent a significant investment in the refining and petrochemical industries ethylene cracking heaters require proper maintenance to assure their long term, safe and reliable operation. The convection section of a heater is subject to varying levels of external fouling from refractory dust and the combustion process. Maintenance of the convection banks is critical for optimum operation and longevity. Accessibility is often a major challenge when operators consider cleaning ethylene cracking furnaces. Tube Tech are able to overcome these challenges by using a self-propelled robotic cleaning vehicle that reaches deep between every row of finned or studded tube to remove the most tenacious fouling bringing the unit back to near new performance.

Robotic Convection Section technology is able to reach deep within all rows of the convection section and remove the most challenging deposits from all types of tube rows. Remotely operated the Tube Tech convection section cleaning robot is a safe, fast and effective convection section cleaning technique available to operators across the world.

No 9 Ethylene Furnace Convection Section Cleaning
The production of ethylene exceeds that of any other organic compound and as of 2013 was being produced by at least 117 companies in 32 different countries. With the global production of ethylene increasing year on year ethylene producers are constantly searching for methods to increase production and reduce energy costs.
Ethylene cracking furnaces are an essential component in ethylene production facilities and are major consumers of energy. The slightest improvement in their efficiency can save operators thousands of dollars and the fouling of the convection section is an area where improved cleaning techniques can make a dramatic difference.

Challenge
• Furnace convection coils are designed to achieve a certain level of performance – the cleaning of the coils is not the furnace designers key focus
• The tight arrangement of tube banks makes access to clean a logistical challenge
• Some furnace convection sections have large inspection and coil removal doors but for many others openings need to be cut for inspection and cleaning
• The inaccessibility of surface areas within deep tube banks leads to many maintenance companies only being able to clean what they can actually see
• Masking from front and secondary rows of tubes can also inhibit accessibility
• Operators have traditionally accepted a reduction in fouling factor of 50% as a ‘cleaned’ condition’ for furnaces which have been in operation for 5+ years.

Solution
• Tube Tech’s specialised Robotic Ethylene Furnace Convection Section cleaning technology is a vehicle which can apply any medium from UHP (ultra-high pressure) and HP (high pressure) water, dry compressed air, high-pressure steam , dry ice CO2, liquid nitrogen, even granulated blast media such as sand and grit in the unlikely event this is ever required.
• The robotic cleaning system cleans deep between both square and triangular pitch rows of convection tubes.
• The system provides a dramatic improvement in cleanliness compared to traditional furnace cleaning techniques such as chemical cleaning, hydroblasting (water jetting) abrasive shot blasting, soot blowers and CO² dry ice blasting
• The Robotic Ethylene Furnace Convection Section technology can be quickly adapted to access the furnace via inspection / viewing doors
• The robot is able to remove the most severe fouling from the entire convection section – circa 98% surface contact plus a 60 ft long section can be cleaned within 4-5 shifts.
• Robotic Ethylene Furnace Convection Section cleaning means no damage to refractory
• The Robotic Ethylene Furnace Convection Section cleaning service includes before, during and after inspection reports

Conclusion
When convection section cleaning is completed successfully flue gases throughout the section will be at reduced temperature levels. The elimination of fouling from within Ethylene furnace convection sections can improve the reliability and asset life of the furnace.