Fuel Oil Burner Development for High Temperature Melting Applications

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11 High Temperature Fiber Optic Probe Oo Inlet Fiber Optic Oil Inlet Atomizing Gas Inlet Oil Lance * Spectrometer Analysis -jj.r.jiimm """'. System Figure 10 : Schematic of the ALGLASS PC™ oxy-fuel burner modified for monitoring the flame emission near the oil atomizer 3.2 Simulating atomization quality degradation Prior to monitoring the atomization quality one needs to properly define what is "good" or "bad" atomization. Furthermore a definition of atomization quality is process dependent and defining atomization quality based on minimum Sauter Mean Diameter for instance is not practical. The flame characterisitics for some applications may require fine droplets at low velocity while others may favor larger droplets at high velocity. Nevertheless what should be emphasized is that typical malfunctioning of the atomizer results in the formation of larger droplets that are usually accompanied by lower trajectories. Since typical atomization degradation results in changes of droplet size, trajectory and spatial distribution, pseudo atomization degradation effects can be simulated by simply changing the atomization pressure. Therefore to demonstrate the monitoring concept of atomization quality changes are simulated by varying the atomization gas pressure. For the example presented here, the atomization pressure is decreased from 4 to 1.5 bar with #2 fuel oil fixed at 70 kg/h and the combustion oxygen flow at 200 N m V h . The monitoring results for the OH and CH bands are shown in Fig. 11. Here the variation in the atomization pressure exhibits a change in the integrated emission intensity for both OH and CH observed by the fiber optic probe. In this case a decrease in atomization pressure increases the integrated OH signal while it decreases the CH signal. 3.3 Primary flame OH and CH characteristics The primary source of the emission observed for both OH and CH is due to chemiluminescence from highly exothermic reactions involving radicals. Flame temperature influences the strength of the emission by increasing the radical population. In addition to the chemiluminescence, thermal emission following the Boltzmann distribution law can also contribute to the observed radiation.