Integração energética na indústria de açúcar e álcool: um estudo de caso

Abstract

This case study shows the application of Process Integration methods, Pinch Analysis in particular, to the sugarcane industry. A large scale, modern sugar and alcohol plant with combined heat and power (CHP) generation capacity was chosen: study was performed upon 2007/2008 crop data from Usina Coruripe, Campo Florido, Brazil. Pinch technology was used to specify site targets for internal heat recovery as well as external utility demands, constrained to the lower, economically achievable exergy destruction. From pinch method results for the base case, and discarding large, deep modifications, a set of five alternatives were selected for system retrofit. The first one was proposed as a means to evaluate systems free time in the base case, which was used to support subsequent comparisons. Cases 3 and 4 were proposed to allow power generation increment, and did not prove worth implementing. Cases 5 and 6 were devised to deal with the plant bottleneck, namely the boiler capacity, and so to allow for production increment. With minimum modifications imposed to the plant, case 5 did not reach appreciable production gain. Case 6, however, showed that, provided the cane juice evaporation section be modified properly and low temperature heat recovery capability be increased, sugar and ethanol combined production can rise up to 9.1% relative to base case, without dropping electric power generation.