Energy and Capital Cost Reduction in Ester Transesterification Using an Optimized Reactive Distillation System with...

Area of Science:

• Chemical Engineering
• Process Optimization
• Separation Technology

Background:

• Reactive distillation is efficient but challenged by azeotropes in processes like methyl acetate (MeAc) and methanol (MeOH) transesterification.
• Valorizing waste streams from the poly(vinyl alcohol) industry, containing MeAc and MeOH, is crucial for economic and environmental benefits.

Purpose of the Study:

• To propose and optimize a reactive distillation with prefractionation column (RDPFC) system.
• To recover high-purity methanol (MeOH) and n-butyl acetate (BuAc) from industrial waste streams.
• To minimize the total annual cost (TAC) of the proposed process.

Main Methods:

• Process modeling and optimization using Aspen Plus version 12.1.
• Integration of a prefractionation column (PFC) under vacuum and a reactive column (RC) at high pressure.
• Comparative analysis with traditional reactive and extractive distillation (RED) processes.

Main Results:

• The RDPFC system achieved a MeAc conversion rate of 99.2 mol %.
• Product purity exceeded 99.85 wt % for MeOH and 99.5 wt % for BuAc.
• A significant 67% reduction in energy consumption (2.56 GJ/tBuAc) was observed compared to RED.

Conclusions:

• The RDPFC system offers a highly efficient and economically viable solution for waste stream valorization.
• Elimination of entrainer and recovery units contributes to substantial energy savings.
• This technology presents a promising approach for the poly(vinyl alcohol) industry.