Careers On-Line Cleaning of SCR Screens
Hot Vacuum Service
Hot-tek provides its patent-pending Hot Vacuum Service for cleaning catalyst banks in SCR (Selective Catalytic Reduction) units attached to steam methane reformers and other fired heaters. We clean SCR catalyst banks during operation, with no interruption to production, offering a rapid payback of associated costs.
Our online SCR catalyst cleaning service removes pluggage and fouling, immediately improving catalyst reduction system efficiency.
SCR Catalyst Screen Fouling
Over time debris, such as ceramic fiber, inorganic dust and combustion by-products entrained in the flue gas accumulate on the upstream face of the SCR catalyst. This debris hinders gas flow through the catalyst increasing the pressure drop across the SCR unit. To overcome this effect, the induced draft fan utilization must be increased consuming extra energy. After the fan has reached max capacity, production must be reduced to decrease the pressure drop across the SCR.
On-Line Cleaning of Catalyst Faces in SCRs
Hot-tek removes the surface debris online with no interruption 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 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.
Online cleaning does not damage the SCR catalyst while removing fouling blockage and deposits.
Hot Vacuum Service for SCR Screen Cleaning
The online vacuum service is possible with any catalyst configuration, vertical, or horizontal flue gas flow direction. In some applications, we use Hot-tek’s Lancescope™ system to inspect hard to reach areas before online cleaning.
In-situ online catalyst cleaning maximizes catalyst efficiency and lifetime, increases plant uptime and reliability.
IGS team provides hot vacuum service around the globe. Our experts have decades of experience and dozens of successful projects each.
SCR Hot Vacuum Service FAQ
Safe and Effective Online SCR Catalyst Cleaning Without Shutdowns
At IGS, our Hot-tek® services are designed to keep SCR systems and emission control equipment operating safely and efficiently, without the need for costly shutdowns. Below, our experts answer the most frequently asked questions, drawing on decades of real-world experience across steam methane reformers, fired heaters, and process plants worldwide.
Do you need to reduce heater duty for hot vacuum service?
No. Hot vacuum service is performed fully online under negative pressure, meaning there is no need to reduce heater duty or interrupt production. This enables continuous operation while restoring SCR catalyst performance.
What is SCR catalyst cleaning and why is it required?
SCR catalyst cleaning removes fouling and debris from the upstream face of the catalyst that restricts flue gas flow. Over time, this buildup increases pressure drop, reduces efficiency, and can force production curtailment. Regular in-situ SCR catalyst cleaning restores optimal flow conditions and system performance.
How much of the catalyst surface can be cleaned during in-situ SCR catalyst cleaning?
IGS engineers design each project to maximize the accessible catalyst surface area with the minimum number of access points. This ensures effective cleaning coverage while minimizing intervention and maintaining asset integrity.
Does hot vacuum service damage the SCR catalyst?
No. The hot vacuum service uses a frictionless, low-impact nozzle specifically engineered to avoid mechanical or thermal damage. This ensures safe selective catalytic reduction cleaning, even on fragile catalyst surfaces.
What causes fouling in SCR systems?
Fouling is typically caused by entrained particulates such as ceramic fibres, refractory dust, fuel contaminants, and combustion by-products. These materials accumulate on catalyst faces and restrict gas flow, reducing efficiency and increasing energy demand.
What are the typical operating temperatures for SCR systems?
SCR systems typically operate in the range of 700–750°F (370–400°C), making online cleaning solutions essential, as shutdown-based maintenance can be costly and disruptive.
How does selective catalytic reduction cleaning improve plant performance?
By removing fouling and restoring gas flow, selective catalytic reduction cleaning reduces pressure drop, lowers induced draft fan load, improves NOx reduction efficiency, and helps return the unit to optimal production rates.
Can in-situ SCR catalyst cleaning prevent unplanned shutdowns?
Yes. Routine in-situ SCR catalyst cleaning helps prevent excessive fouling buildup, which can otherwise lead to high pressure drop, reduced throughput, and forced outages. Maintaining clean catalyst surfaces supports continuous, reliable operation.
Are there solutions to prevent SCR fouling after cleaning?
Yes. IGS provides a complete fouling mitigation strategy, including refractory encapsulation coatings such as Cetek, as well as mechanical solutions like screens and air cannons. These solutions address the root causes of fouling and extend catalyst life.
Trusted Online SCR Catalyst Cleaning Without Shutdowns
IGS Hot Vacuum Service has been trusted by refineries, petrochemical plants, and hydrogen production facilities worldwide to restore SCR catalyst performance without interrupting operations. With proven online procedures, non-damaging tooling, and decades of field experience, our teams deliver reliable, repeatable results where uptime and emissions compliance are critical.
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