Robotic Ethylene Fired Heater Convection Bank Cleaning in The Netherlands

Over €5m energy saving per year and avoiding €5m in replacement cost!

Costly replacement of a Cracking Furnace Convection Bank was avoided by one of the world’s largest Ethylene producers by using Tube Tech’s Unique Robotic Cleaning Technology to fully clean its Steam Cracking Furnace Convection Bank Coils. This dramatically improved heat transfer which increased throughput, far exceeding our clients’ expectations.

The Challenge

Convection coils consisted of both finned and bare tubes.
Fouling was estimated as being 2 to 4mm thick, light, friable scale adhered and bridging external tube and finned surfaces.
Access to convection section was via small manways and inspection hatches.
Cleaning was completed within 36 hours off-line (during shutdown) using 2 Robots.
Distortion of some coil banks had to be overcome.
Fin design found to be both standard smooth design but also sharp serrated unspecified on drawings.

The Solution

Robots removed near 100% of fouling from all convection tube banks.
Access was gained through small inspection hatches to clean all convection banks.
Distorted heater coils and serrated fins were overcome by minor robot modifications.
Inspection teams confirmed levels of cleanliness had been exceeded using endoscopes before and after fouling removal.

Safety

No refractory was damaged as Robots are programmed to direct and deflect high pressure medium off the tubes.
Man entry was not required.
Robots are air powered therefore intrinsically safe.
Inspection is carried out using low 25 volt CCTV equipment.

Tube Tech Comment

“€8m energy saving is not an uncommon Client benefit after Robotic Cleaning of their Ethylene Fired Heater. Our Robots unlock this hidden and previously inaccessible saving by the removal of 90%+ fouling compared to 1% from conventional methods,” says Christian Chanel, Technical Sales.

“Every fired heater project has its unique challenges whether due to limited access, unknown fouling levels even design changes omitted from client drawings. All credit to our R+D team and site operators who proactively overcame every obstacle”.

Due to the huge financial and Co2 benefits I strongly recommend a yearly “Fouling preventative” clean as 1mm of fouling reduces overall heater performance by 10%!

Client Comment

“The root cause of the decreasing performance of the furnace was reduced heat transfer in the convection section due to external fouling.

After robotic cleaning by Tube Tech, the heat duty of each convection bank increased by 11% and the % stack loss reduced by 16%. The quality of high pressure steam generated was improved. Thorough cleaning avoided damage to the low temperature sections and flue gas fan. The external cleaning was a success and will similar savings over the next few years.