Premixed Radiant Burners: Improved Process Performance with Ultra-Low NOx Emissions

In the past decade, users and manufacturers of industrial combustion systems have been attempting to reduce NOx emissions generated by these systems to meet ever more stringent regulations. These efforts have led to some improvements in the understanding and application of traditional flame burners with the introduction of staged combustion burners and flue gas recirculation. These approaches are based on stretching existing technology to achieve incrementally better emissions characteristics, but have not made any comparable improvements in the underlying thermal performance limitations of these burners. Premixed radiant burners represent a new approach to industrial combustion which combines inherently low NOx emissions with significantly improved thermal performance. Beginning in 1983 with the retrofit of a muItitank asphalt heating system, Alzeta Corporation has introduced Pyrocore® and Pyromat TH radiant burners to a variety of industrial applications, demonstrating their enhanced performance. Since then, the range of industrial applications which have seen widespread use of these burners include: fired process heaters, immersion tube heaters, firetube boilers, industrial air heaters, incinerators, and direct-fired paper dryers. The benefits which users of these systems have obtained include: low NOx emissions, increased system thermal efficiency, improved heat flux uniformity and responsiveness, and increased capacity on existing system retrofits. This paper describes the burners, their application histories, and the performance benefits achieved by these many applications.