Qualitative and quantitative dynamic control analysis of pressure-swing distillation with varied-diameter columns

In its simplest design, pressure-swing distillation (PSD) can have high energy demand and some modifications can be made to make it more economically attractive. Among possible modifications, the use of varied diameter columns (VDC) can reduce capital costs. In addition to design, determining a control structure is also a crucial factor. Within this context, this work aims to evaluate the control performance of a pressure-swing distillation process using VDC to separate acetone/methanol mixture. Three control schemes were evaluated. The control performance of the PSD-VDC was compared with the process with uniform diameter columns (UDC) under feed disturbances using Pseudo Random Binary Sequence (PRBS) signals. The Integral Square Error (ISE) was the criterion used to compare the performance of the control schemes evaluated. According to the results, the PSD-UDC system presented lower ISE values for the product composition, showing that the use of PSD-VDC is not superior to PSD-UDC in terms of control for the system studied. According to the ISE values obtained, the control scheme that uses the steam-to-feed ratio is considered a good alternative for the process.

Automated summary

This study evaluated the control performance of pressure-swing distillation using varied diameter columns (VDC) and found that in the studied system, the PSD-UDC system had better control performance compared to the PSD-VDC system. According to the obtained ISE values, the control scheme using steam-to-feed ratio is considered a good alternative.