The separation of butadiene 1,3 from pyrolysis products is a critical step in the petrochemical industry, as butadiene is a key raw material for producing synthetic rubber and other polymers. This study presents a detailed model-based analysis of the separation process, focusing on optimizing operational parameters to maximize butadiene recovery, enhance product purity, and reduce energy consumption. The simulation was conducted using Aspen Plus, evaluating critical variables such as the solvent-to-feed ratio, reflux ratio, number of column stages, and energy integration between distillation units. The simulation results indicated that an optimal solvent-to-feed ratio of 1.5:1 and a reflux ratio of 4.2:1 in the extractive distillation column provided the highest separation efficiency. Under these conditions, the recovery rate of butadiene 1,3 reached 98%, with a final product purity of 99.5%. Furthermore, this study revealed that increasing the number of theoretical stages in the distillation column improved the separation process without significantly increasing energy demand. Energy integration, specifically through heat recovery between the primary distillation and extractive distillation columns, led to a 12% reduction in total energy consumption. These findings demonstrate the importance of fine-tuning operational parameters to achieve high separation efficiency and product quality while minimizing energy use. This model-based analysis provides valuable insights into the design and optimization of industrial-scale butadiene separation processes, offering strategies to reduce operational costs and improve sustainability in production. The methodology and results can serve as a basis for further improvements in similar separation processes across the petrochemical industry.

The separation of 1,3-butadiene from pyrolysis-derived C₄ fractions represents a challenging task due to the multicomponent nature of the feed and the close boiling points of accompanying hydrocarbons. In this study, a two-stage extractive distillation process was investigated using an acetonitrile–water solvent system to address these challenges. A semi-industrial experimental unit consisting of two extractive distillation columns connected in series was developed and analyzed, and the process configuration was supported by Aspen Plus simulation. The feedstock composition was characterized in detail, revealing that 1,3-butadiene constitutes approximately 40 wt.% of the C₄ fraction, accompanied by significant amounts of propylene, butanes, butanes, and a non-negligible C₅ fraction. Component-wise mass flow analysis showed that the absolute butadiene load reaches about 480 kg/h for a total feed flow of 1200 kg/h, emphasizing the need for a robust and flexible separation scheme. These results demonstrate that the separation problem is governed not only by relative composition but also by high throughput and heavy-end loading. The two-stage extractive distillation configuration allows the separation task to be distributed between columns, facilitating selective interaction between the solvent and 1,3-butadiene while managing light and heavy hydrocarbon components. The presented experimental framework and modeling approach establish a consistent methodological basis for evaluating separation efficiency and further optimization of industrial butadiene recovery processes. The findings confirm the suitability of staged extractive distillation for processing complex pyrolysis C₄ streams with high butadiene content.