Separated OFA Systems

Introduction of staged secondary air as "overfire air" is the single most important NOx performance component in any tangential low NOx system retrofit. Whether it is located in the main windbox or separated, it should provide the highest NOx reduction efficiency. The FW Secondary Air Staging systems provide the following specific features:
Compact separated windbox design minimizes installation costs associated with tube panels, buckstays and other boiler house modifications. Optimum vertical and horizontal placement assures highest NOx reduction efficiency and maximizes fuel/air mixing during this critical stage in the combustion process. Adjustment capability is provided for maximizing fuel/air mixing, through horizontal yaw, velocity, and flow control. Separated staging windboxes are fitted with turning vanes. The associated connecting duct designs are designed to minimize system resistance, reducing auxiliary power requirements. Minimal number of nozzle tips and linkages are applied to improve reliability and reduce long term maintenance. All components are designed and fabricated for long term reliability.