A comprehensive analysis of uncertainty in thermal utilities: 3E case study of a sugar plant

Heat losses from the utilities are inevitable in industries which utilize heat in unit operations. Sugar processing plants are among the industries where energy is a considerable share of final product. Accurate thermodynamic and economic analyses in sugar industry depend strictly on estimation of heat losses from the surfaces of utilities. In this research, the evaporation line of a sugar plant was studied to investigate the error introduced by ignoring heat loss in the system performance. To this end, energy, exergy, and exergeo-economic (3E) analyses were performed. Mean temperature of the surfaces of all the evaporation line subsystems was measured using thermography and the heat losses from the surfaces were computed. The results of 3E analysis show that ignoring heat loss in the evaporation line, generates considerable deviations from actual values. Total energy loss, total exergy destruction, and total cost, had errors of 2.24%, 0.72%, and 0.90%, respectively. As for the case studied project, the 0.90% difference in the total cost is equal to 11.04 USD hr(-1) which is equivalent to 18.50% of the cost of natural gas consumption in the plant and accounts as a highly critical issue for industrialists.