Exergy-Based Sustainability Assessment of Mass-Integrated Suspension PVC Production with Direct Water Recycling Using Computer-Aided Process Engineering

The suspension polyvinyl chloride (PVC) industry is characterized by intensive water and energy consumption, making process integration an attractive strategy for improving resource efficiency. Previous studies have demonstrated the technical, environmental, and safety benefits of direct water recycling in suspension PVC production; however, the thermodynamic implications of this integration have not been evaluated. Therefore, this study presents an exergy-based sustainability assessment of an industrial-scale suspension PVC production process incorporating direct water recycling through mass integration using a Computer-Aided Process Engineering (CAPE) approach implemented in Aspen Plus®. Physical and chemical exergy were calculated for all material and utility streams under pseudo-steady-state conditions, and exergy balances were performed for the main process sections to determine exergy destruction and exergetic efficiency. The integrated configuration achieved an aggregated stage-level exergetic efficiency of 93.0%, representing a 16.8% improvement over the conventional process, while freshwater consumption and wastewater generation were reduced by 16.0% and 26.3%, respectively. Recovery and purification accounted for the largest share of total exergy destruction (39.2% and 36.4%), indicating that downstream separation operations dominate the thermodynamic inefficiencies of the process. Although direct water recycling introduced additional local irreversibilities associated with recycle operations, the integrated configuration improved the utilization of available exergy while reducing water consumption and wastewater discharge. These results demonstrate that exergy analysis provides complementary information beyond conventional water–energy–product indicators and constitutes an effective tool for identifying thermodynamic improvement opportunities in industrial PVC production systems.