OPTIMIZATION OF ENERGY CONSUMPTION OF PARAXYLENE EXTRACTION PLANT

Paraxylene is a key component in the production of polyethylene terephthalate and polyester fibers. Existing technologies for its extraction from aromatic hydrocarbon mixtures including multistage rectification and adsorption are characterized by high energy intensity, which reduces the economic efficiency of the processes. The aim of the study is to optimize the technological scheme of a paraxylene extraction plant by upgrading the rectification unit to reduce energy consumption while maintaining a high recovery rate of the target product. The article’s structure includes an analysis of the technological features of the existing plant (Section 700), a description of its components (adsorption chambers, rectification columns), and identification of key issues related to the use of furnaces to maintain temperature regimes. The research methodology involves an analysis of the current scheme, calculation of equipment thermal loads, and modeling of an upgraded system. The focus is on replacing the 92DT-941A/B column with a high-pressure column (up to 9 kgf/cm²), which eliminates furnaces and integrates heat exchange between process streams. The proposed solutions include: • transition to a high-pressure rectification column in Section 900В; • replacement of furnaces with reboilers utilizing the heat from the overhead product to heat column bottoms; • optimization of heat flows between technological units. The results demonstrate a significant reduction in energy consumption: total gas savings reached 3.689·10⁷ kcal/h, and electricity savings amounted to 3.840·10⁷ kcal/h. The modernization maintained a high paraxylene extraction rate (up to 99.9 % wt.) while reducing operational costs. This work provides practical solutions for improving the energy efficiency of paraxylene extraction plants, which is critical for the petrochemical industry in the context of growing demands for resource conservation.