COBEM99

S1 Análise de Sistemas Energéticos

Title:

THERMODINAMIC ANALYSIS OF THE COGENERATION SYSTEM OF A BRAZILIAN ALCOHOL AND SUGAR CANE MILL

Summary :

BRAZILIAN ALCOHOL AND SUGAR CANE MILLS HAVE EMPLOYED COGENERATION FOR DECADES TO PRODUCE ELECTRICITY FOR INTERNAL CONSUMPTION. ONLY AN INSIGNIFICANT AMOUNT OF ELECTRICITY IS SOLD TO THE GRID, WHICH IS FED MAINLY BY HYDROELECTRICITY. RECENTLY, THOUGH, SEVERAL FACTORS HAVE COMBINED TO MAKE THIS ALTERNATIVE NOT ONLY ATTRACTIVE BUT NECESSARY. "USINA VALE DO ROSÁRIO", WHOSE COGENERATION SYSTEM IS SUBJECT TO STUDY IN THIS WORK, IS ONE OF THE FEW SUGARCANE MILLS CURRENTLY SELLING ELECTRICITY TO GRID, 4 MW FOR THE MILLS OF 1996 AND 1997. THE MILL IS COMMITTED TO A STEADY GROWTH IN THE AMOUNT OF ELECTRICITY SOLD. MODIFICATIONS. INTRODUCED IN THE PLANT IN 1998, SUCH AS THE ACQUISITION OF AN ADDITIONAL TURBINE, HAVE ALREADY ALLOWED AN INCREASE FROM 20 TO 32 MW IN TOTAL GENERATED ELECTRICITY AND FROM 4 TO 15 MW IN SOLD. AMONG THE AIMS OF THE WORK WERE TO DETERMINE THE REAL COSTS OF POWER AND HEAT SUPPLIED BY THE COGENERATION SYSTEM AND TO SUPPLY INFORMATION FROM WHICH OPERATIONAL DECISIONS COULD BE TAKEN. REAL DATA WERE AVAILABLE AND WERE USED THROUGHOUT THE ANALYSIS. DUE TO INSUFFICIENT INSTRUMENTATION, IT WAS NECESSARY TO SIMULATE THE PLANT IN ORDER TO INFER SOME OPERATIONAL PARAMETERS OF EQUIPMENT, WITH THE HELP OF INFORMATION SUPPLIED BY THE MANUFACTURERS. THE SIMULATION SOFTWARE IPSE WAS EMPLOYED. THERMOECONOMIC ANALYSIS WERE PERFORMED FOR THE 1996 AND 1997 CROPS. THE EFFICIENCIES AND THE DESTRUCTION OF EXERGY IN EACH UNIT WAS CALCULATED, AS WELL AS THE EXERGETIC COSTS, AS DEFINED BY THE THEORY OF THE EXERGETIC COST, A COMMENDABLE THERMOECONOMIC METHODOLOGY. THE IMPORTANCE OF HIGH EFFICIENCIES OF THE STEAM GENERATORS IS OVERWHELMING. THE LOW EFFICIENCIES OF MECHANICAL DRIVERS INCREASE THE COST OF MECHANICAL POWER, COMPARED TO THE COST OF THE GENERATED ELECTRIC POWER. THE COST OF THE STEAM SUPPLIED TO THE DISTILLERY SUGGESTS THE ADOPTION OF MEASURES TO REDUCE ITS CONSUMPTION.

Author :

Barreda del Campo, Eduardo Rafael
Nebra, Silvia Azucena
Nebra, Silvia Azucena

Paper View :