Green Solvent Alternative for Extractive Distillation of 1,3-Butadiene

The separation of 1,3-butadiene from C4 hydrocarbon mixtures is a crucial step in the production of synthetic rubbers and plastics. Conventional extractive distillation methods using solvents, like N,N-dimethylformamide (DMF), have proven effective but presents significant health and environmental challenges. This study explores the feasibility of using propylene carbonate (PC) as a green solvent alternative for butadiene extractive distillation, leveraging its environmentally friendly properties and industrial compatibility. Simulations were conducted using Aspen Plus�, employing the Non-Random Two-Liquid (NRTL) model coupled with the Redlich-Kwong equation of state to describe phase equilibrium. Results indicate that PC integrates seamlessly into existing processes, achieving comparable operational stability and butadiene separation efficiency with minimal modifications. A significant design improvement was the elimination of the methylacetylene separation column in the PC process, which simplified the overall configuration and reduced cooling water requirements by approximately 43 tonnes per hour. This change resulted in a 0.4% reduction in utility costs. While PC�s higher boiling point requires operational adjustments, such as the use of higher medium-pressure steam, the overall energy consumption was 3.7% lower than with DMF. These findings demonstrate that PC is a viable and sustainable alternative for butadiene recovery processes, offering economic, operational, and environmental benefits.