Coen Company, Inc.

Temple S Voorheis

Norman E Harthun

Chester S Binasik

Ralph R Vosper

Louis D Siegert

James H White

To minimize NO.sub.x emissions in an intermediate size industrial boiler furnace having two vertically spaced rows of burners, each upper burner has a central fuel nozzle and a main air opening adjacent to the nozzle and communicating with a wind box associated with the furnace. In addition, each upper burner has a plurality of air delivery ports through the wall surrounding said upper burner, such air delivery ports also communicating with the wind box. The air delivery ports can be of different sizes and shapes and can be at different angles with respect to the vertical plane of the wall through which the air delivery ports extend. Control of the air through the main air opening adjacent to the nozzle of each upper burner is achieved by one or more shiftable registers or dampers which operate to close the air flow from the wind box to the air opening. Each lower burner has the same construction as each upper burner except that the lower burner does not have the air delivery ports through the wall surrounding the nozzle and its adjacent main air opening. Typically, each lower burner is fired off-stoichiometrically with only about 70% theoretical air and each upper burner is fired with about 90% theoretical air, the make-up air for each upper burner coming through the air delivery ports arranged around it. The air delivery ports also provide the makeup air for the excess fuel through the lower burners. The air pressure of the air across the air delivery ports has a higher pressure than the air pressure across the main air openings adjacent to the fuel nozzles. This assures that the make-up air through the surrounding air delivery ports will penetrate deeply into the combustion chamber of the furnace.

System for the reduction of NO.sub.x emissions

A staged, high efficiency burner for gaseous, liquid or pulverized solid fuels (including fuels having a high nitrogen content) in which NOX emissions are minimized. The burner includes a burner basket having a base including a throat and a concentric, tubular, frustroconically shaped wall that defines a primary combustion space. The fuel and primary air of about 75% of stoichiometric air are introduced into the basket which has a length so that the fuel has a residence time therein of between about 0.1 to 0.5 second. Secondary air is introduced into the flame downstream of the basket in the form of a multiplicity of individual air streams which are oriented to penetrate the flame and spin it about its axis so as to maintain a substantially cylindrical flame periphery. Part of the secondary air can be introduced through the tubular wall of the basket to shorten the flame length while maintaining the low level NOX emissions and the high efficiency of the burner by directing that part of the secondary air into the primary space so that the formation of pockets which have a high or excess air content cannot form. The flame basket can be disposed fully within the combustion chamber of the furnace or, to prevent it from penetrating excessively into the chamber, part of the basket can be disposed outside the chamber.

High efficiency, low NOX emitting, staged combustion burner

A burner which has a central liquid fuel atomizing nozzle is disclosed. An inner member defines a steam chamber and is surrounded by a shell that defines a liquid fuel compartment. A conduit extends from the steam chamber forming a steam core flow. A first passage feeds liquid fuel about the steam core flow to form an annular liquid fuel stream thereabout. A second passage forms an outer steam flow which envelops the annular liquid fuel flow. The burner further includes ducts to form a first combustion airflow co-axially about the nozzle, a second combustion airflow which surrounds the first flow, and a third combustion airflow which envelops the second flow and generally protects the furnace wall from coming into contact with the flame generated by the burner. Gas spuds are placed in the second combustion airflow and each spud includes a discharge plate which generally faces in the direction of combustion airflow and which has one or more gas discharge holes arranged to cause the gas streams to substantially cover the entire space occupied by the gas stream downstream of the nozzle and upstream of the combustion chamber of the furnace. The plates of the spuds are relatively thick and the gas is supplied to the spuds at a relatively low pressure.

Parallel flow burner

A flame forming burner for simultaneously minimizing excess air consumption while suppressing NO.sub.x emissions. A dual zone air register is provided to supply primary air in substoichiometric quantity into mixture with fuel to produce a flame in a primary zone. Additional air is introduced around the flame and downstream of the initial combustion site in a secondary zone, in sufficient quantity to complete combustion. In the preferred embodiment, primary air is provided through a venturi throat, and secondary air is provided through an annular passage equipped with vanes which generate dual counter-rotating (DCR) air flow surrounding the primary zone. Dampers for each register control the primary to secondary air ratio. Preferably, a divergent, non-circular throat provides flame shaping.

Flame forming burner

An oil fired burner adapted to produce a variable asymmetrical flame shape. The burner includes a tip head carrying a plurality of tips disposed in at least two orientations, i.e., axial and off-axis. The relative rates of fuel supply to the tips is controlled to afford asymmetric flame shaping. In a typical application in a rotary cement kiln, the flame is biased to increase the heat transferred to the load in the front end of the kiln and to decrease the heat transferred to the top and sides of the kiln.

Variable flame shape oil burner

An integrated method is disclosed for preparing and suspension firing of bagasse and the like as the primary fuel for steam power generation in a cane sugar refinery. The method comprises mixing wet bagasse with de-ashed hot flue gases of a steam boiler, thereby drying it; separating bagasse dried thereby from the drying flue gases, capturing substantially all suspended dust; sizing the dried bagasse; directing bagasse fines to temporary storage while grinding and resizing any oversize bagasse; metering out and pneumatically suspending the fines, providing a smooth-flowing fuel responsive to a burner fuel feed control means; combusting the suspended fuel in a scroll feed type burner firing the steam boiler; de-ashing the combustion effluent, and utilizing the resultant flue gases for drying wet bagasse. Alternatively, the wet bagasse may be dried partially by de-ashed hot flue gases and partially by a bagasse fired supplementary hot air dryer, thereby further improving boiler operation efficiency.

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Atherton, CA, United States of America

Temple S Voorheis