Catalytic reforming converts low-octane, straight-run naphtha fractions, particularly heavy naphtha into a high-octane, low-sulfur reformate, which is a major blending product for gasoline/petrol.
The process is endothermic and is carried out by feeding a naphtha and hydrogen mixture to a furnace, where it is heated in a series of fired heaters to the desired temperature, 450° to 520°C (840° to 965°F), before passing through a series of reactors.
Coating Refractory Lining
The Emissivity of typical refractory linings in fired heaters ranges from 0.45-0.65. When radiant energy encounters these refractory linings, much of the energy is reflected back and is absorbed into the flue gas and carried out of the radiant section, into the convection section and out the stack, with the majority never reaching the process.
High emissivity coatings for refractory surfaces increase surface emissivity to 0.92, a near black body. Radiant energy is absorbed by the high emissivity lining and reradiated across a broad spectrum. The reradiated energy is able to penetrate the flue gas and be absorbed by the process, increasing radiant section efficiency.
Optimizing the operation of Catalytic Reforming Units is critical as these fired heaters consume large amounts of energy to provide the required heat for the process.
Cetek partnered with PTTGC, Thailand, for a ceramic coating application in their CCR Platforming Heaters. Upon completion of the successful field application, once back in service, the results exceeded expectations and provided an excellent projected ROI over the lifetime of the coating.
The unit was in a scheduled outage in October 2019, at which time the fireside of the tubes in the boiler were inspected by robotic UT. Wastage was discovered on both sidewalls above the existing field applied overlay, rear wall slope and burners, and front wall slope and burners. The type of damage is typical for opposed wall fired pulverized coal boilers operating in a reducing atmosphere with low NOₓ burners.
IGS was contracted to install 5450 EPRI Proven HVTS Alloy Cladding over the damage zones. IGS offered a rapid response and addressed the areas during the week of November 4, 2019. The IGS solution is a rather fast application – a total of 2,000 square foot of boiler tubing was protected with HVTS in 5 short days.
The project was executed in accordance with the IGS Safety Program. Safety is, and always will be Integrated Global Services’ first and highest priority. Our Management Team is dedicated to becoming the industry leader in Health and Safety while our excellent safety record bears witness to this fact. A continuous improvement process is utilized that enables all levels of personnel to take part in identifying and fixing hazards associated within the workplace. This is marked by our Safety Committee that involves members of all areas and levels of IGS.
IGS Thermal Spray projects are performed in accordance with the IGS quality control standards which have been developed in to meet customer requirements. All site work will be executed in accordance to the accepted Quality Control Plan (ITP/QCP) and accompanying method statement. The final project QC package will be issued along with this report.
WTE Boiler Fireside Corrosion of Alloy 625 Weld Overlay Cladding
The Hitachi Zosen Inova (HZI) furnace installed at Renergia is an inclined moving grate four-pass waste to energy boiler with an external economizer. The boiler’s thermal capacity is 47MW with the steam flow of 58 t/h and steam pressure of 41 Bar at 410°C.
Alloy 625 weld overlay was shop-applied on the fireside water wall panels to protect the WtE boiler tubes from fireside corrosion. After months of operation, an inspection revealed accelerated degradation of the Alloy 625 just above the grate.
Several solutions were considered to manage the boiler tube metal wastage and improve reliability and lifetime of the water walls, including replacement, field applied weld overlay and thermal spray.