METHOD OPTIMIZATION OF SEPARATE SECTIONS IN SUGAR PRODUCTION

Abstract

method of thermoeconomic optimization of separate section of a typical sugar plant. was developed. Since the main part of exergy losses is due to heat transfer at the finite temperature difference, the value of temperature drop in each of the section s was chosen as an independent variable in thermoeconomic optimization with the corresponding search for their minimum thermoeconomic costs. The existence of a local minimum for each section is due to the fact that with increasing temperature drop increases the amount of energy costs (because the exergy losses increase) and decreases the amount of capital and related costs (because the heat transfer surface of the sectione decreases), and, consequently, their sum will have a minimum. The search for this minimum due to the unimodality of the thermoeconomic cost function was performed for each section by the Gauss-Seidel method - by sequentially comparing the costs obtained at this step of the iteration with the previous ones and, if the value is less, move on to the next iteration. If the value found becomes greater than the value obtained in the previous step, which will be optimal. Then the total thermoeconomic costs in the section are calculated. As an example of application of the developed method searching the optimum temperature drop and local optimums of annual thermoeconomic expenses for the first degree were found. The found value of the temperature drop exceeds the corresponding in the existing evaporation system by 2.6 degree and maintaining such an increased temperature drop in the first section allows you to reduce the annual costs in this section at 3800 USD. It should be noted that the found values of temperature drop due to the rigid link to the technological chain of each section require mutual agreement, because the flows coming from the previous sections are simultaneously included in the next, and therefore the temperature level of processes in sections must change, thereby changing the amount of thermoeconomic costs. In addition, it should be taking in amount that a change in the parameters of the flows within the energy technology system of the evaporation system will also cause a change in the parameters of the flows that leave this system.