Date of Award
The purpose of this case study is to optimize the design and production of an ethylbenzene-to-styrene manufacturing facility, Unit 500. Compared to the original base-case design, the optimizations presented in this document will save approximately $337 million dollars without compromising the production requirements or quality. Optimization of this process used net present value as an objective function, with changes centered around the reactors, but also the separation equipment and exchangers prior to separation, as those devices most directly controlled process stream contents and conditions. The second set of reactors was removed in favor of using one optimized set of reactors, in addition to decreasing the three-phase separators temperature and modifying both the number of trays and the material of construction for the distillation towers. A utilities and exchangers analysis was performed, but the course of action found from it was deemed unrecommended due to excess complexity of the new model. Separately, an isothermal styrene reactor was optimized for 5% minimum conversion utilizing PRO/II, and found that
A more detailed market analysis and a second optimization cycle is recommended before making a firm decision if building the facility to produce styrene would be preferred to purchasing it from the open market, but current market conditions suggest that manufacturers of styrene are more likely to use it to produce higher-value products rather than selling it in bulk. In this case, securing a styrene vendor is unlikely and making the styrene will be preferred, as the value from producing polystyrene later in the process will offset the losses in Unit 500.
Michels, John, "Optimization of an Ethylbenzene to Styrene Production Facility" (2022). Honors Theses. 2622.
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