The refinery had been experiencing reduced performance due to fouling on convection bank tubes within a steam methane reformer. Due to the inaccessible location of the tubes, the unit had not been cleaned since it came online in 1993. Tube Tech’s fouling removal robot was chosen to access and remove fouling, restoring heat transfer efficiency.
The plant experienced reduced heat transfer, higher fuel consumption and an increase in flue gas temperature within its steam methane reformer. The problems arose from the adsorbents in a Pressure Swing Absorption Unit, part of the refinery’s Hydrogen Manufacturing Unit (HMU), being changed during a turnaround.
Once started up, some of these adsorbents were transported by the tail gas stream and facilitated by misplaced screens in one of the beds; the result was an accumulation of fouling on the convection bank tubes of the steam methane reformer.
The client became aware of Tube Tech’s specialist fouling removal robot which had been deployed successfully around the globe in some of the most challenging environments. Tube Tech’s expertise in reaching hard-to-access areas was particularly useful for this project and the team was tasked with restoring heat transfer efficiency.
The team mobilized during a planned turnaround period and deployed the Tube Tech patented fouling removal robot, which can penetrate deep between tube rows to remove more than 90% of fouling. Traditional cleaning methods can typically only clean approximately 30% of the convection bank. The project was completed within 60 hours.
The average cost of hydrogen production before and after the project was calculated at $943.9-919.3 $/t. The production cost of hydrogen decreased by $24.6/t and the payback period for the project was less than 60 days.
The average flue gas temperature decreased from 278°C to 220°C. This translates to a 3% increase in the furnace’s thermal efficiency.
Steam production increased by approximately 20%, and the generated steam temperature increased by 10°C-15°C.
“This was a great project to be a part of; we often come across convection banks that have never been cleaned before, simply because they are deemed inaccessible or too difficult to restore to design efficiency.
“Tube Tech researches and develops its own unique technologies, ensuring that fouling can be removed as precisely and efficiently as possible. Due to this bespoke approach, we are proud to be able to guarantee heat transfer restoration for our clients.
We look forward to working with the refinery on future projects.”
As well as Tube Tech’s fouling removal services, the refinery also utilized another IGS solution by applying a Cetek high-emissivity coating onto the refractory surface to increase radiant section efficiency.
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