Location: Coal fired power stations across NSW and QLD

Download Case Study pdf


The water-wall sections of IHI boilers at power stations are required to be periodically cleaned to remove metal build-up including magnetite and copper deposits. This is typically performed at five year intervals for each boiler. The chemical clean process is around the clock, and typically takes four days.

Chemical circulation

Verico’s mechanical testing team are responsible for inducing and controlling chemical circulation during boiler cleans.

IHI boilers are designed to work on the principals of natural circulation and are not fitted with circulation pumps. Verico has developed a method which induces circulation in the water-wall sections of the boiler by injecting gas into each downcomer. This creates a differential in liquid densities in various sections of the water-wall system which induces the circulation.

The flow in each downcomer is monitored using ultrasonic flow measurement equipment, and controlled by modulating the gas flow.

Products and services provided

  • Engineering support and coordination
  • Provision, installation and removal for all temporary equipment
  • 24 hour monitoring and control of flows


Verico’s services in boiler chemical cleaning have been used for several decades in the Australian industry to increase coal fired boiler life and thermal efficiency.