Analysis of Variance and Significance of Innovative Melting Techniques for Energy Conservation in Ferrous Foundries

Abstract

The natural sources of energy coal, oil, gas etc. are depleting fast. Energy consumption is major problem being faced by the Indian ferrous foundries. “Bureau of Energy Efficiency, “The Energy Research Institute,” Govt. of India New Delhi & other International agencies has reported that energy consumption in Indian ferrous foundries is much more above the required limits and has to be drastically reduced. This paper deals with Experimental Investigations of oxygen enrichment of preheated air in LDO-fired rotary furnace, for optimal specific fuel and energy consumption. The author conducted experimental investigation on oxygen enrichment of preheated air in a self designed and developed 200 kg rotary furnace in an industry. Initially when furnace was operated under existing conditions, at 2 rpm, the fuel consumption is 0.415 liter/kg or 415 liters/tone and energy consumption is 4.11045 Kwh / kg or 4110.45 Kwh/tone. In view of reducing the energy consumption, furnace was operated with 6.9% oxygen enrichment of 75.3%-75.4% of theoretically required air at 1 rpm. The fuel consumption reduced to 0.260 liter/kg or 260 liter/tone and energy consumption reduced to 2.575Kwh/kg or 2575.0 Kwh/tone. The percentage reductions are 37.349 %and 37.354% respectively. Further the furnace was operated with 7.7-8.4% oxygen enrichment of 61.1-64.9% of theoretically required air at 1 rpm. The fuel consumption reduced to 0.208 liter/kg or 208 liter/tone and energy consumption reduced to 2.060kwh/kg or 2060.0 Kwh/tone. The percentage reductions are 49.87% and 49.88% respectively. The statistical analysis of variance and significance has been carried out to verify the experimentally investigated results to generalize them for any size of furnace. The deviations and variations are within acceptable limits of ±5%.The test of significance rejected the prevailing hypothesis that reducing rpm or increasing oxygen enrichment does not reduces the fuel and energy consumption.