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Show Current Research While there is no doubt that high intensity burners are more economical in every situation where operating costs are weighed against capital costs, it is generally acknowledged that their higher operating temperatures result in higher NOx emissions over competing TDF burners. Given the higher flow of excess air required by TDF burners, and the corresponding cooling of flame temperatures, TDF burners do achieve low NOx emissions. But this apparent benefit is offset by higher CO levels, and greater overall emissions resulting from higher fuel consumption and exhaust mass. The aim of the current research is to create a high intensity burner which, without losing any of its inherent benefits, will be able to compete effectively in the developing low NOx market of the next decade. The standard AECOmetric High Intensity Burner generates NOx emission rates from 53 to 138 ppmv under a wide range of industrial applications. Conamara's research goal of reducing NOx emissions to the 20 ppmv level has already been exceeded, with experimental devices achieving test results well below 10 ppmv. Apparatus A special version of the AECOmetric 10 MM BTU/hr (2.9 MW) High Intensity Burner was developed for the Low NOx research program at AECOmetric Corporation (see figure 1). It features various sets of ports into the combustion chamber to allow for air staging experiments. The design permits staging of secondary air both in the combustion chamber itself, and into the post vortex flame region. The test furnace was designed to isolate the effects of the system from the performance of the burner. It features a 1100 gallon (5000 ~ bath of water surrounding an uninsulated shell for a firing chamber 5 ft in diameter by 14 ft long (1.5m x 4.25m). The cold shell helps to cool the exhaust gases quickly to quench post burner chemical reactions. The exhaust stack has been sized at 30 inches (76 cm) square to handle burners up to 30 MM BTU/hr. The piece of equipment used to analyze the exhaust gases is a portable combustion analyzer. It is an Enerac model 2000E with detectors for CO (0-500 ppmv±2%), No (0-500 ppmv ±20/0), S02 (0-2000 ppmv ±2% ), CH4 (0-6 ±0.10/0), 02 (0-21 % ±0.1 % ) and a permeation dryer for sample conditioning at the point of withdrawal. The Enerac 2000E was calibrated twice during the experiments with no changes to the original factory settings. The sampling point for withdrawing exhaust has is five feet above the end of the firing chamber at the centre of the exhaust stack. All flows of gas and air were measured with orifice plates fitted to water manometers. Page 3 |
