Mark IV Transportation Products Corporation

Joseph H Werling

Robert T Brady

George A Weller

Dean C Townsend

A method and apparatus for low NOX combustion of natural gas in a compact steam boiler having output steam delivery controlled by predetermined outlet steam pressure. The compact boiler employs a small high heat release combustor discharging into a forced draft convective heat exchange section. In operation, the compact boiler is completely and automatically self-operating, employing flue gas recirculation (FGR) wherein the FGR is admitted into the burner combustion air through a valve controlled by boiler flue gas NOX content. A novel bell mouthed flue gas scoop is utilized in the boiler stack upstream of the NOX sensor. In an alternate combustion chamber design, a cylindrical water wall coil surrounds the combustion process, increasing boiler efficiency through the inherent large temperature difference between the coil and the combustion in process, along with reducing the combustion temperature and further reducing the NOX content of combustion products. A further variation in the combustion system utilizes a ceramic shield surrounding a natural gas burner as it fires into the compact combustion chamber. Primary and secondary combustion air are admitted to the combustion chamber through first stage combustion internal of the shell and second stage combustion occurring internal of the boiler combustion chamber.

Method and apparatus for low NOX combustion of gaseous fuels

Method and apparatus for reducing the NOX levels in stack emissions of compact boilers and fluid heaters through selective injection of exhaust flue gases into the combustion process. Flue gas injection into the primary and secondary air of the burner along with flue gas injection directly into the combustion process is utilized. Injection of generated steam obtained from various components of a compact boiler, selectively injected into the combustion process is also provided.

Compact boiler having low NOX emissions

Method and apparatus for reducing the NOX levels in stack emissions of compact boilers and fluid heaters through selective injection of exhaust flue gases into the combustion process. Flue gas injection into the primary and secondary air of the burner along with flue gas injection directly into the combustion process is utilized. Injection of generated steam from a compact boiler, selectively injected into the combustion process is also provided.

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Mundelein, IL, United States of America

Joseph H Werling