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Specialty Custom Solutions

In-situ SCR Catalyst Cleaning

We offer a solution to safely clear catalysts of potentially harmful contaminants that cannot be reached, dislodged or removed by traditional methods.

Services > Specialty Custom Solutions > In-Situ SCR Catalyst Cleaning



Proprietary Technology

Our proprietary method vacuums and blows within a containment from above the catalyst while vibrating the catalyst layers from the bottom, safely cleaning catalysts of potentially harmful contaminants by removing fly ash that cannot be reached by traditional methods. The catalyst does not have to be removed from the unit and the process prolongs catalyst life.


Clears Your Unique Plugging Issue

Whether you are dealing with hardened fly ash, popcorn ash (LPA), or MgO plugging, results continually show the catalyst to be effectively cleared of chemical and physical deactivation substances, a decrease in pressure drop, increase in reaction surface, decrease in ammonia slip and increased plant efficiency.

Safely clear catalysts of potentially harmful contaminants.


  Regeneration companies recommend this method be used to clean the catalyst before the modules are sent out for regeneration.

  It is the most effective method to prevent flyash release during highway transportation per EPA guidelines.

  Cleaning prevents moisture from accumulating in the plugged modules during transportation, which leads to hardening.

  It can reduce regeneration cost due to the prior cleaning.

  Turnkey comprehensive SCR cleaning incorporates vacuuming, proprietary sponge blasting process, module-encapsulation ash recovery & proprietary vibratory equipment and processes.


 Decrease in Pressure Drop

 Decrease in Ammonia Slip

 Reduced catalyst poisoning

 Cleared of chemical & physical deactivation substances

  Increase in Reaction Surface

 Increase in Plant Efficiency

 Reduced Risk of Boiler Shutdown

Case Study


A major coal fired power plant was experiencing operational difficulty in coal-fired boilers due to the blinding of the SCR catalyst surface area by fly ash from the fuel combustion. This 441 MW Coal-fired power plant was built in 1976 with an SCR consisting of three layers, 1150 mm length Ceram catalyst with 45 modules per layer. Low quality coal and poor system design has traditionally required a very high rotation of catalyst (particularly the top layer, changed as often as every 6 months). In fact, when Thompson was given the opportunity to clean the reactor, the client had already ordered a replacement layer due to the amount of pluggage and ash build-up within the existing layer.

Thompson’s in-situ SCR catalyst cleaning method cleared the plugging significantly in just 4 shifts using our proprietary methods combining vacuuming, sponge blasting and our unique pneumatic vibration technology.



Utilizing Thompson’s unique and custom-designed, proprietary foaming equipment and dust-encapsulating foaming agent, the Thompson 3-man crew was able to clean all of the tripper room walls, supports, and 30’ ceiling with never having to lift their boots off the tripper room floor.


As the result of Thompson’s in-situ SCR catalyst cleaning technologies and services, client was able to avoid replacing the layer thus reducing the outage period and saving the layer of already purchased catalyst for future use. SCR catalysts have a typical operational lifetime of about 16,000-40,000 hours in coal-fired power plants. However, with the thorough cleaning and maintenance Thompson provides, those hours can be significantly extended.

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