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Show STACK RECUPERATOR FEEDER MELT BATH FCTP=fe^. BURNERS Figure 1. Submerged Combustion Melter However, numerous experiments conducted on different submerged combustion melting furnaces with different melts have shown that simply injecting a combustible mixture into a melt (for example, through tuyeres) does not ensure stable combustion. Cold channels are formed which lead to explosive combustion and excessive melt fluidization. Olabin has studied this through theoretical analysis of both a physical model of the ignition of a combustible mixture within a melt and a mathematical description 0 ) . For the majority of practical melt conditions, the ignition of a combustible mixture injected into the melt as a stream was found to start at a significant distance from the injection point. This leads to the formation of cold channels of frozen melt and explosive combustion. To avoid this condition, the combustion system must be designed to minimize the ignition distance. This can be done in one of three ways: 1) by using special devices to stabilize the flame at the point of injection, 2) by splitting the fuel-oxidant mixture into smaller jets, and/or 3) preheating the fuel-oxidant mixture. Submerged combustion burners must provide: • a stable flame at the fuel-oxidant injection point into the melt, • constant, stable, and reliable ignition of the fuel-oxidant mixture, • highly uniform distribution of the fuel-oxidant mixture across the melt bath cross-section, • long service life with simple maintenance, • high turndown ratio, • no flashback potential. The Gas Institute has designed and successfully operated several types of multiple-nozzle burners that meet the above requirements. Figure 2 shows one of these designs used on the commercial furnaces. A newer design for air-gas and oxy-gas burners has been introduced and successfully operated 2 |