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Show ABSTRACT ... Development of a High Performance Versatile Low NOx Burner Vladimir Lifshits Coen, Inc. 1510 Rollins Road, Burlingame, CA 94010 The paper describes the development process of a new Coen low NOx high performance burners and the transition from a successfully tested prototype to a commercially available product. The performance data are illustrated by the results achieved at the test facility and in numerous package and field erected boilers. The burner was the first commercial product that could fire Natural Gas with NOx emissions below 30 ppm and low carbon monoxide emissions without the use of flue gas recirculation (FGR) in a wide variety of package boilers. For the boilers with low space heat release rates the burner achieves even lower NOx in the range 15-20 ppm. The burner is specifically suited for industrial duty applications, as it does not impose any special requirem.ents to the control system, like tight air fuel ratio, 02 trim, etc. The burner achieves 10 to 1 turn down and with some modifications allows turn down in the excess of 15 to 1. The burner can easily fire other gaseous fuels like refinery gas and does not require special gas preparation, as the typical minimum diameter for the gas discharge is more than 1/8". The versatility of the burner is also enhanced by its ability to operate with induced or selective FGR as it allows NOx reduction down to the 12-15 ppm level. While most of the burner performance can be realized when firing gaseous fuel, liquid fuels like #2 and #6 oil can also be fired separately or simultaneously with gas. Change over between fuel can be done on line. INTRODUCTION The development of this new low emission burner was prompted by new regulations requiring lower and lower NOx emission standards country wide. Until recently the only practical way to reduce NOx emissions from packaged boiler firing Natural Gas to the level of 30 ppm was to operate with a significant amount of FGR, that was resulting in an increase in capital and operational cost and in some instances reduction in the boiler efficiency I and capacity. This paper describes the development of a new type of burner that achieves 60-80% NOx reduction, when firing gaseous fuels, and 20-30% lower emissions, when firing oil without using FGR. The burner was developed in various modifications that together comprise a unique class of fuel staged burners with one specific feature in common: combustion air and primary gaseous fuel are rapidly mixed together and discharged into the furnace through a series of radial slots. The trade name of these class of burners is QLN. The primarily applications for QLN burners are retrofit and OEM markets of packaged and field erected boilers. The development of the burner was launched in late 1992. In 1993 numerous 40 and 50 MMBtu/Hr prototypes were extensively tested at the Coen company test facility. The first introduction to the market was in early 1994, when a 75,000pph B&W packaged boiler was retrofitted with model QLN-3.4, firing natural gas or jet fuel without the use of FGR. In this boiler the burner demonstrated less tha~ 30 ppm N~x ?n ~as . Dur~ng 19~4 and 1995 the development continued. The burners were deSigned and bUilt In different sizes with the capacity ranging fr 20 to 200 MMBtu/Hr. Modifications of the burner were developed to accommodate numero om specific applications: refinery gas type fuels, high combustion air temperature, selective FG~~ |