Energy, exergy, economic, and environmental analysis of a novel liquid-only transfer dividing wall column with vapor recompression

The Kaibel dividing wall column (KDWC) uses a thermal coupling technology for separating quaternary mixtures, which exhibits less energy consumption and more economic benefits than a conventional distillation sequence (CDS). However, it is hard to control the vapor split ratio, which limits the industrialization of KDWC. The liquid-only transfer dividing wall column (LDWC) doesn’t involve the vapor split ratio. It has been verified as equivalent to KDWC. To improve LDWC’s performance further, four novel vapor recompression-assisted LDWCs are proposed according to the column grand composite curve analysis. And CDS and LDWC are taken as the base cases for comparison. Then, the processes are optimized by the sequential iterative optimization procedures to minimize the total annual cost. The performance of optimized processes is systematically evaluated through energy, exergy, economic, and environmental (4E) analysis. The results demonstrate that the SCVRC-IR-LDWC2, equipped with a side condenser and intermediate reboiler involved in lower vapor side stream withdrawal, performs well in the total annual cost, energy consumption, gas emissions, and thermodynamic efficiency.