Análise de um sistema de gestão de energia e do carregamento de motores elétricos em uma indústria petroquímica

Abstract

This final paper analyzed the Energy Management System of a petrochemical plant, the methodology used for continuous control of the energy performance of the plant, the energy baselines and the action plans discussed at the Internal Commission for Energy Conservation meetings. In addition, it was evaluated the loading of 20 three-phase medium voltage induction motors through the expedited linearization method of the conjugate curve. By checking the plate data and measuring the working speed of these motors, a mean load of 54% was found in the motors analyzed, and the calculation of the average efficiency resulted in 69%. It was also proposed a retrofit to replace a motor of 775cv by another of 500cv, from the analysis of the electricity bill of a substation of raw water pumping. With this, it was verified a possibility of annual savings of R$ 565,650.74 in the energy and pay-back bill of 7 months. However, through the evaluation of the active power supplied to this engine and the flow provided by the driven centrifugal pump, the operating point of the pump was within the region of highest efficiency of the pump, according to the characteristic curve provided by the manufacturer. It was concluded, therefore, that the expedited method presents very low accuracy to be used as non-intrusive method of evaluating the energy efficiency of electric motors in the industry.