Metodologia para análise exergética-econômica de plantas a vapor para geração de eletricidade consumindo resíduo de biomassa amazônica

Abstract

The availability of energy resources price increasing promotes directly impacts the social-economic development. The rise for energy in Brazil, the efficient use of energy as strategic activity for the industrial sector. The energy evaluations employed in this sector aims to optimize the efficiency of its thermal systems. This energy performance assessments is based on the First Law of Thermodynamics and are able to quantify only the loss of energy, different from exergetic evaluation that allowing qualify this energy lost. The exergetic analysis is difficult and time consuming, requiring the development of a protocol to be performed quickly. In this case, the protocol must attend particularitities of the Amazon biomass, as well as it´s environment. This paper proposes and applies a methodology of energy and exergetic analysis as well as exergo-economic analysis a steam power plant installed at Belém, Pa funning on Rankine cycle. After these evaluations, the energy rate and energy losses are gotten, and also exergy rate and it’s rate destruction, the cost rate for each product and the monetary cost of the energy produced by the plant in R$/kWh. Such results, make possible to identify the largest energy losses of the power plant, quantify the cost of destruction of exergy in key equipment and the rate of cost of main products of the plant that are thermal energy and electricity. This allows quantify the energetic, economic and exergetic performance in each of the plant equipment and indicating the processes that deserve a development work to improve their economic efficiency. Moreover, the cost of the energy capacity in R$/kWh produced by power plant steam was compared with the value charged for the local energy utility. This comparison showed that power plant has energy cost less than the utility price.