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Balancing of Pulverised Fuel

Improvement of fuel distribution across the burner zone (and across the boiler load range) is key to delivering improved combustion performance and associated coal-fired boiler performance optimization.

This is achieved through measurement and understanding of fuel flow and associated velocity specific to each burner PF pipe configuration  followed by the necessary adjustment to fuel flow using appropriate flow balancing technology.  This helps facilitate improved alignment of air flow and fuel flow thereby helping to establish the required air to fuel ratio (AFR). 

/media/systems/library/perspective1.jpgAddressing improved fuel distribution and  associated burner-burner AFR is fundamental to managing emissions to air such as NOx, and CO particulates etc.. It is also fundamental to  addressing other combustion performance related challenges associated with fireside corrosion, carbon-in-ash as well as slagging & fouling within the furnace.  Delivery of improved  combustion stability is also fundamental to improved flexible operations and minimum stable generation (MSG).

In addition to fuel distribution, PF particle size distribution can have a significant impact on burner combustion performance.  Good management of PF particle size distribution through appropriate management of the milling system is essential.  Therefore, on-line measurement and monitoring of mill exit PF particle size distribution will help facilitate appropriate mill management and help ensure fuel is delivered to the burner zone at the required particle size distribution.

/media/systems/library/didcot.jpgWhilst addressing and managing key influencing factors such as burner-to-burner fuel distribution, fuel quality and particle size distribution are essential to delivering improved combustion performance with commensurate improvement in boiler  performance, there are other factors that must be addressed.  Management of combustion zone stoichiometry (theoretical plus excess air necessary for complete combustion) is a further key element that must be addressed.

Combustion zone stoichiometry is managed via the addition of appropriate Primary & Secondary air flow to the furnace. Getting the balance right is extremely important but is often undermined via excessive 'uncontrolled' furnace air ingress (tramp air) or in-leakage at other locations such as the air-heater and duct seals.

Key to facilitating improved combustion performance is the balancing of fuel distribution across the burner zone,  management of fuel quality and PF particle size distribution and minimising uncontrolled air ingress to ensure the combustion zone operates at the required air-fuel-ratio.