Reducing Power Boiler Emissions Via "In Furnace Control"

The very stringent Italian Environmental Regulations have forced ENEL and Ansaldo to implement advanced technologies to control power boiler emissions (NOx, CO, excess Oxygen and Particulate). These technologies have been applied, both in Italy and abroad, on over than 20.000 MWe both on tangentially and front or opposite fired boilers and for different fuels (coal, oil, gas and ORIMULSION). Taking advantage of: a) innovative Low NOx burners design (TEA MK1 & 2 for oil and gas and TEA C for oil and coal) b) new overfire air ports design characterized by extremely low pressure drop c) optimized air staging and reburning techniques it has been possible to attain NOx reductions up to 85%, with no significant impact on boiler efficiency and reliability and - most important - without substantially increasing emission level of other pollutants (CO and particulate) or worsening final excess air. Operational NOx levels as low as 90 ppm firing oil have been guaranteed and obtained