جستجوی مقالات مرتبط با کلیدواژه "conceptual design" در نشریات گروه "مهندسی شیمی، نفت و پلیمر"

A batch process was developed for biodiesel production from high free fatty acid feedstocks. The mixed-integer nonlinear programming (MINLP) problem caused due to applying of hierarchical procedure together with Malone’s algorithm for conceptual design was solved. Meanwhile, the optimum states of major process parameters such as the utilization of process equipments, paralleling, splitting, and merging of unit operations, process cycle time (CT), and combination of batch and continuous units were determined. Based on the present optimization study, the optimum value of process cycle time and the optimum number of the esterification reactors in series were obtained as 3.257 h/batch and 3 stages, respectively. The batch process was found to be suitable for a capacity of less than 260 tons/yr, while the continuous process was suitable for a capacity of greater production rates. The results showed that the production rate had a direct effect on the economic potential of the process and that it should be set at its maximum possible practical value. Also, the break-even point at the optimum state occurred at 130 tons/yr of production rate.

A continuous process was designed and optimized at conceptual stage for biodiesel production from waste vegetable oils. Unlike previous studies, the process was optimized taking into account the technical and economic considerations, simultaneously, to find the optimum operating conditions in the commercial scale productions. The effect of major design variables on the process yield was studied by modeling of esterification and transesterification reactors. Free fatty acids’ (FFAs) mole fraction in feedstock, production rate, conversion and molar ratio of the reactants in both reactors were chosen as major design variables. By considering the economic potential as objective function of process optimization, the optimum FFA mole fraction was obtained as about 0.50 (24 wt %). Also, the optimum values of conversion and molar ratio of the reactants in the esterification and transesterification reactors were found as 82-89% (depending on the different production rates), 11:1 and 96%, 8:1, respectively. It was found that economic potential increases linearly as production rate increases. Therefore, the production rate should be set at its maximum possible practical value. The break-even point at the optimum values of these variables, as mentioned above, occurs at the production rate of 157 ton/yr.