Furnaces Fired Heater Convection Bank Cleaned Robotically at German Refinery

Furnace cleaned using remote mechanical operation

A German refinery requested that Tube Tech develop a robotic cleaning technology to clean deep in between both square and triangular pitch rows of convection tubes within its fired heater to improve poor cleanliness achieved using traditional water jetting and chemical service contractors. The “Remote Controlled Furnace Robot” was born, delivering an unprecedented level of cleanliness within record time. This included the removal of fused refractory that had cemented itself between the tubes over many years.

The client had previously trialled many systems including chemicals, water jetting, abrasive shot blasting and dry ice, which were limited in success as blast methods only clean what the operator can see. Access deep inside and between the furnace rows was never achieved. Refractory damage has always been an issue when using conventional cleaning methods.

The Challenge

The contract duration was limited to only 48 hours to clean three levels on two fired heaters containing six 15m long convection banks.
The furnaces had not been cleaned properly for over 20 years.
The heaters were being changed from oil to gas firing and it was important the tubes were free from hydrocarbon fouling to ensure maximum heat transfer, reduced fuel consumption and asset life.
No damage to the refractory was allowed and sulphuric acid vapour needed containing.

The Solution

The fired heater doors measured 500mm x 500mm, but the remotely controlled furnace robot was built to access small 150mm x 200mm doors.
The remotely controlled furnace robot’s biggest advantage is that it can remove extremely hard deposits deep within every tube row whether design is square or triangular pitch providing 360-degree tub surface contact as the fired heater is shut down and off-line.
Tube Tech inspected the unit before, during and after cleaning. Multiple systems were used simultaneously. No refractory was damaged.

Tube Tech Comment

“This was challenging because our three R&D engineers were given only three weeks’ notice to build three multi-functional robots. This takes fired heater cleaning to a new level and overcomes all obstacles of limited access allowing robotic cleaning to be done via small and awkward access doors. The savings on fuel and CO2 emissions were substantial. Robotic cleaning of fired heaters will extend run times, reduce: tube distortion, replacement, fuel use and CO2 emissions and spells the end to un-cleanable furnace convection tubes.”

Client Comment

“From my side thanks again for your work and smooth execution of the job. It is a considerable task to perform all the cleaning in only five days and with only a few weeks of preparations. Well done, very successful job!

“What I can say is the stack temperatures of the furnaces dropped by 50°C in HVU2 and 80°C in CD2, which is a considerable increase in furnace / energy efficiency. We are talking about several megawatts of energy savings! Various out-of-the-box cleaning techniques and ideas from Tube Tech could certainly improve our performance, heat exchangers as well as furnaces.”