A method and an apparatus for optimizing the
combustion air
system in a power boiler or
chemical recovery boiler by improving fluid flow and
gas mixing are disclosed, whereby one can increase boiler capacity and
combustion uniformity and reduce particulate and gaseous emissions. The method involves interlacing of the secondary and, where applicable, the
tertiary air supply through opposing air ports on all four walls of the boiler, and is implemented by alternately opening wide or partially closing a port
damper on one side, while partially closing or opening wide a port
damper on the opposite side, such that a 70-100% open
damper on one side opposes a partially closed (10-40% open) damper on the other and vice versa in an alternating fashion, along opposing walls. In a preferred embodiment, the optimization is further enhanced by balancing primary air flow, achieved by adjusting port dampers and windbox pressures so that the primary air flow is evenly distributed between opposite walls, between all four walls of the boiler and between individual airports on each wall. Windbox pressure and other key measurements of boiler operation ensure proper balancing and an adequate interlacing of air flows at the primary, secondary and
tertiary elevations, respectively.