Techno-energy-enviro-economic multi-objective optimization to determine the best operating conditions for preparing toluene in an industrial setup

摘要

The operating condition for an experimental setup is usually determined using design of experiment method. However, it does not guarantee to achieve the best possible condition. Therefore, as the novelty, this study aims at using multi-objective optimization for this purpose, by which it could be sure that the best possible condition will be determined. In addition, energy, technical, environmental, and economic indicators have not been taken into account at the same time for finding the best condition before, whereas, as another novelty, they are all considered here. The multi-objective optimization is employed to determine the optimum operating temperature and pressure in an industrial process of toluene production as a solvent. Hildebrand solubility parameter, as well as economic benefit and consumed energy per unit mass of product, have been considered as the objective functions, while carbon dioxide emission has also been taken into account as the environmental function that is optimized to acquire a cleaner production line. According to the results, compared to the design of experiment method, the Hildebrand solubility parameter has been enhanced from 13.32 to 16.11 MPa0.5. Moreover, the benefit increased from 0.0488 to 0.0708 $ kg(-1) while the energy production per mass of product had a 71.66% reduction. Acquiring a much cleaner production line to prepare the solvent is also guaranteed by employing the multi-objective optimization where the carbon dioxide emission has been reduced from 0.0793 to 0.0225 kg per unit mass of the prepared solvent. Decreasing both temperature and pressure from 534.15 to 381.65 K, and from 2.50 to 1.10 MPa, respectively, is another big advantage of the employed multi-objective optimization method, which leads to a safer condition.