Investigação da eficiência energética na indústria de fundição

Abstract

Since the 1973 oil crisis, which strongly affected energy policies, several countries have been studying ways to reduce their dependence on fossil fuels, without harming the evolution of their economy. In Brazil, a country with a predominantly renewable electricity matrix, a series of blackouts that took place from 2001 onwards led the government to institute administrative measures and reduction practices, such as programmed blackouts and taxation of sectors or consumers that did not meet energy saving targets expected. The investigation of the reasons that led to these events revealed, among other things, the need to diversify the energy matrix and the importance of creating incentives and energy efficiency measures. In this context, after sectoral analysis of energy consumption in the country, it was observed that the industrial sector is historically the largest consumer, however, it is also the sector that least develops energy efficiency practices, as seen over the years by ODEX Brasil. Highlight for the ferroalloys, steel and pellets sector, which has large energy demands, being then selected the foundry sector for study. Historical data from ABIFA were analyzed, concluding that within this industry few energy efficiency projects are contemplated, even though energy is a high-cost input within this industry. It is then studied in this work how the distribution of energy in industry behaves, and after identifying the largest input consumed (in this case electricity), the various aggregate losses in the processes were investigated, for example, in the material melting stage, the losses arising from the poor quality of the scrap to be melted, in the engines, the oversizing of this equipment or the luminous inefficiency in the sectors. So, after researching through already recognized bibliographies, practices were found to mitigate losses in the melting stage, lighting, motors, pumps and exhaust fans, new technologies that could be applied in this industry were also raised. Some of these practices are: Use of pre-heaters, measures that reduce electricity demand by around 30 to 60 kWh/t, insertion of a “shunt” magnetic flux concentrator, reducing coil losses by up to 5%, reuse of residual heat, cleaning the metallic load, among others.