Patent ID: 8617315
Filing Date: 2013-12-31
Classification: C13B,Y02E,Y02W

Abstract:
1. A process for the recovery of water and energy from the processing of sugar cane in sugar and ethanol production mills, using the sugar cane straw and bagasse as energy source for an electric energy and steam generation unit and comprising the steps of: a—submitting the sugar cane to a juice extraction operation with imbibition by condensates recovered from vegetal vapor; b—treating and purifying the extracted juice, using vegetal vapor condensate, evaporation vegetal vapor and inputs, and producing a clarified juice flow, a sludge flow and a vegetal vapor condensate flow; c—treating the sludge flow, producing a filter cake and a recovered juice flow which is returned to the step of treating and purifying the juice; d—submitting part of the clarified juice flow to a multiple effect vacuum evaporation unit, under heating by exhausted steam from the energy generation unit, producing: an exhausted steam condensate, to be at least in part returned to the energy generation unit; at least one evaporation vegetal vapor flow; a last effect vegetal vapor flow; a vegetal vapor condensate flow; and a syrup flow; e—concentrating the syrup until the crystallization point of part of the sucrose contained therein under heating with at least part of the vegetal vapor flow produced in the evaporation unit, producing a crystallization vegetal vapor flow, a vegetal vapor condensate flow and a crystallized product flow (crystallized mass); f—centrifuging the crystallized product, producing end syrup (molasse) flow and a sugar flow to be dried and bagged; g—mixing the remaining clarified juice flow with the molasse flow in proportions adequate to the fermentation, and cooling the resulting must by indirect thermal exchange, with at least one of the means defined by an extracted mixed juice flow and a vegetal vapor condensate water flow, at the wet-bulb temperature corresponding to the ambient temperature, circulating by a cooling tower unit; h—maintaining the fermentation temperature between 25° C. and 36° C., by indirect thermal exchange with the vegetal vapor condensate water flow circulating by a cooling tower unit; i—fermenting the cooled must, producing a wine flow, and distillating the wine to produce ethanol and vinasse, wherein: the extracted juice (mixed juice) is pre-heated in the cooling of the must and heated by regenerative indirect thermal exchange with at least one of the flows defined by last effect vegetal vapor of the evaporation unit and by the crystallization vegetal vapor, transforming said vapor flows in vegetal vapor condensate flows; the step of distillating the wine is carried out with the indirect heating of the wine by at least one of the means defined: by part of the evaporation vegetal vapor flow; by part of the exhausted steam flow; and by a vinasse vegetal vapor flow, producing an alcoholic vapor flow and at least one of the flows defined by vegetal vapor condensate and by exhausted steam; the alcoholic vapor flow is condensed by indirect thermal exchange with at least one of the flows defined by fermented wine and by vegetal vapor condensate water of the cooling tower unit; the vinasse is submitted to a multiple effect vinasse evaporation unit, under heating by evaporation vegetal vapor, producing: at least one vinasse vegetal vapor flow; a last effect vinasse vegetal vapor flow; a vegetal vapor condensate flow; and a concentrated vinasse flow; the wine, to be distillated, is pre-heated by indirect thermal exchange with at least one of the means defined by the last effect vinasse vegetal vapor flow and by an alcoholic vapor flow from a distillation stage, producing a vegetal vapor condensate flow and an alcoholic condensate flow; the excess of the vegetal vapor condensate flows which is not used in the process is sent, at least in part, to the cooling tower unit and, if it is still available, stored for posterior treatment.