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Fired heaters, including catalytic reformers, steam methane reformers, crude & vacuum heaters and ethylene furnaces, among others operate at very high flue gas temperatures, up to 1000oC (1800oF). Traditionally, essential maintenance within these units could only be performed during a shutdown.
Problem Areas
Hot spots resulting from damaged refractory, scaled or misaligned process tubes, plugged SCR catalyst banks, and fouled convection sections can all affect the performance, reliability and safe operation and ultimately the operating capacity of the fired heater. If a planned shutdown is still years away, Maintenance Managers are faced with a dilemma. To accept the risks and inferior performance or attempt temporary repairs, potentially still risking an unplanned shutdown if the solution is not fit-for-purpose.
Refineries, Petrochemical and Agrochemical Plants rely on the Hot-tek service, delivered by Integrated Global Services (IGS) to effectively address fired heater maintenance challenges in between turnarounds, without the need to shut down or power down their fired heaters.
Hot-tek services include Hot Refractory Repair, Hot Tube Stabilization, Hot Vacuum Service, Hot Inspection Service, and Hot Convection Cleaning.
Hot spots
Misaligned tubes
Fouled convection section
Scaled tubes
Plugged SCR catalyst bank
How it Works
Each service has been designed and perfected in collaboration with major oil and gas refineries to ensure that the safety, performance, and the output of the fired heater is not compromised.
Hot Refractory Repair Services
Hot Refractory Repair Services are performed by making access through the heater steel shell directly behind the damaged area. Minimal openings are used to insert specially designed components to support the repair material. This technique offers a semi-permanent repair method utilizing a high-quality refractory material with full structural reinforcement.
If access points are not available, Hot Access Creation may be used as an integral part of the refractory repair process. In some applications, Hot-tek’s LancescopeTM system is used to see hard-to-reach areas of the fired heater.
Hot spots
Repair in process
Repair completed
Benefits of Hot Refractory Repair:
- Performed at normal operating conditions
- Restores structural integrity of refractory
- Eliminates threat to shell steel integrity
- Allows unit to return to full load
Case Study: Fired Heater Shutdown Prevented with Hot Refractory Repair
A refinery in the U.S. has discovered serious refractory integrity concerns on its CCR unit. The refractory ceramic fiber was missing in a furnace. As a result, the outer steel shell was damaged due to the exposure to the high temperatures in multiple areas of the roof and sidewall.
IGS Hot-Tek team was invited to repair the damaged refractory roof areas, using Hot-Tek Hot Refractory Repair Services, while the unit was running at full capacity. All quoted areas of the furnace roof were repaired, along with two additional damaged areas, discovered during the project. Read more about this project.
Hot Tube Stabilization
Process tubes can be stabilized while the heater is still in full operation. The stabilizer can either be supplied by the asset owner or fabricated by Hot-tek.
Misaligned tubes
Repair in progress
Tube alingned
To perform hot tube stabilization, Hot-tek will make access in the vicinity of the failed tube support, insert the stabilizer, then weld the stabilizer in place, replacing the refractory and the external steel shell in the repair area.
Benefits of Hot Tube Stabilization:
- Prevent unplanned shutdown
- Installation during normal operation
- No need for continuous monitoring
- Lasting semi-permanent repair
Case Study: Tube Support Installation during Plant Operation
Two tubes in a vacuum heater have partially lost their tube support. The retaining bar fell out of place. In order to prevent a potential unplanned shutdown in the future, IGS Hot-tek delivered a turnkey solution, installing tube stabilizers while the heater continued normal operation. Read more about this project.
Hot Convection Cleaning
This tube cleaning process uses consumable abrasive media projected through specially designed application lances to blast away years of accumulation, while the heater is in service.
In some applications, the Hot-tek’s LancescopeTM system is used to see hard-to-reach areas. In addition, IGS Hot-tek teams have the capability to safely create engineered access ports to facilitate the hot convection section cleaning process and for future access.
Fouled convection section
Convection section cleaning
Hot-tek online convection tube cleaning is efficient, environmentally friendly, and safe for the removal of years of fouling and scale without interruption to production.
Benefits of the Hot Convection Cleaning:
- Improved fired heater efficiency by removal of fouling on convection section tubes
- Reduced stack temperature
- Increased process pre-heat and steam production
- Improved draft
Case Study: Increasing Furnace Efficiency with Hot Convection Cleaning
Crude Heater with significant process preheat was overfiring. Convection tubes were fouled leading to High Bridgewall and High Stack temperatures. IGS performed Hot-Tek cleaning through existing access doors. Total absorbed duty increased with a decrease in firing leading to Increased Furnace Efficiency. Read more about this project.
Hot Tube Descaling
The Hot Tube Descaling Process removes radiant section process tube fireside soot, scale & fouling during furnace operation. The process uses unique water-cooled lances. The process utilizes consumable abrasive media resulting in no increase in emissions.
In some applications, Hot-tek’s Lancescope™ system is used to see hard-to-reach areas. IGS Hot-tek also have the capability to safely create engineered access ports. These ports can be used to facilitate the hot tube descaling process.
Hot tube descaling: Before and after
Hot tube descaling: Before and after
Typical results of the hot tube descaling process include bridgewall temperature reduction of 50°F (10°C) to 100°F (38°C).
Benefits of Hot Tube Descaling Service:
- Improving fired heater efficiency by removal of scale
- Reduced tube surface temperature
- Reduced bridge wall temperature
- Especially effective in catalytic reforming units
Hot Vacuum Service
On-Line Cleaning of SCR Screens
The online SCR catalyst cleaning service removes plugging and fouling of SCR screens, immediately improving catalyst reduction system efficiency.
Hot-tek removes the surface debris online with no interruption impact on production or environmental emissions. Existing access points may be used upstream of the catalyst for the insertion of Hot-tek’s equipment. If necessary, reusable access ports can be created online with Hot-tek’s hot access creation service.
A vacuum lance with a non-damaging low friction tip is inserted into the ducting. The nozzle is placed against the surface of the catalyst and the Lance is manipulated by a technician with no damage to the fragile catalysts. Observation of the vacuuming is maintained with line of sight or through the Hot-tek’s Lancescope™ viewing system. Vacuuming progresses from port to port across the length of the catalyst wall. Each access point is closed before moving to the next location.
Without fouling obstructing the gas flow syngas production can be returned to normal and ID fan usage can be reduced.
Hot Vacuum Service returns SCR Catalyst Bank operation to maximum efficiency by restoring the pressure differential across the catalyst to an “as-new” condition. Decreasing pressure drop, hot SCR screen cleaning eliminates wasted energy consumption and strain on the ID fan motor. Furthermore, it ousts the potential curtailment of production due to gas flow blockage or excessive NOx production. Increased DeNOx potential and mercury oxidation return SCR efficiency.
The online vacuum service is possible with any catalyst configuration, vertical, or horizontal flue gas flow direction. In-situ online catalyst cleaning maximizes catalyst efficiency and lifetime, increases plant uptime and reliability.
Benefits of the Hot Vacuum Service:
- Restoring differential pressure to optimum level
- Reducing electricity consumption of ID fan
- Extending life of ID fan motor
Case Study: Hot Vacuuming Prevents Emergency Shutdown
The Plant was in danger of needing an emergency shutdown to clean their catalysts. Hot-tek LanceScope inspection identified screen fouling. Cleaning of 200 catalysts was then performed online without interruption to production. Read more about this project.
Hot Inspection Service
Hot-tek’s Lancescope™ system provides real-time, close-up or wide-angle views of virtually any area inside a fired heater, or other high temperature equipment while it is still operating. The hot inspection system uses a state-of-the-art digital camera system, which provides clear, detailed images of problem areas up to 3000°F (1650°C). The furnace inspection system can be inserted into openings as small as 2.75” (7cm) and reach up to 30ft (10m). In applications below 1000°F (540°C), the heater inspection system provides illumination via a high temperature light source for optimum clarity.
The Lancescope™ technology is supplemented by a complete infrared thermography analysis, temperature tests, and emissivity measurements.
Contact them for more information about essential maintenance fired heater services or visit their website.
