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Show RESULTS AND DISCUSSION S.E.R. Radiant tube temperature distribution reflects the different nozzle design for each burner size. As shown in Fig.5, the temperature maximum of the tube surface is closer to the end of the length when vice versa the same maximum is closer to the tube beginning for 4.5" and 6.0" SER burners. Due to the ceramic firing and radiant tubes, maximum temperature and heat flux are much higher for 3.25" SER's than for metallic 4.5" and 6.0" SER burners. To compare the temperature uniformity of different size butane operated SER burners, the relative temperature difference (T'-factor) was calculated using the following equation: T' = [ (T max - T min) /T av x 100%, where T max, T min, and T av are maximum, minimum and average temperatures in oc respectively. This data is plotted in Fig.6. As shown, the furnace temperature increase determines the relative tube temperature difference T' reduction for each expertized burner operated on butane. High uniformity temperature level (T'= 1.8 - 2.6%) is achieved for 920 - 9800 C furnace temperature. Natural gas, propane and butane nozzle operation comparison shows no significant difference in relative tube temperature difference (Fig.7). The best uniformity has been achieved with the natural gas nozzle (2.3%). The butane nozzle gives T'= 2.4%, and the propane 2.7%. Observing the tube surface through a viewing port, shows the even bright yellow/red color along the tube length. Fig.8 reflects the stable combustion range on butane operation. The operational zone envelope for 4.5" SER's is much wider for inputs lower than 60% of maximum. The 3.25" SER and 6.0" SER burners have almost the same operational zone envelope. The top -8- |