Energy-Efficient Design of a Novel Double Annular Separation Column Using Pinch Pressure

Abstract

This study introduces a pinch-based method to design an internally heat-integrated pressure swing distillation (HIPSD) with a double annular column. In the configuration, the annular stripping section of a low-pressure (LP) column partially wraps around the rectifying section of an inner high-pressure (HP) column to minimize exergy loss. In order to enable adequate heat transfer and azeotropic separation, the key factor is setting the pressure of the columns by considering the so-called pinch pressure, which is determined by the minimum temperature approach and circumvention of the azeotropic boundary. This heat integration between two individual columns reflects different overall heat transfer coefficients for each stage, because they are affected by the composition of the fluid and its hydrodynamic characteristics. Each column is also sized to meet hydraulic conditions to ensure separation efficiency. The HIPSD of several azeotropic mixtures was described and the maximum energy savings reached 23.80%.

Synthesis of heat‐integrated pressure‐swing azeotropic distillation using a graphical pinch analysis

“…The phase equilibrium temperature of these two product streams depends on their composition and pressures by the phase rule. For example, in a binary azeotropic system of water and ethanol, pure water is produced at the bottom of the LP column, and the minimum‐boiling azeotropes are formed as overhead vapor in the HP column 28 . Since the binary compositions behave on the one‐dimensional composition line, the product composition under the total reflux condition can be fixed as singular points of pure water and an azeotrope at their respective pressures 47 .…”

“…For the feasible design of externally heat‐integrated PSD (HIPSD), the temperature difference between these two columns must exceed the pinch temperature defined as the minimum temperature difference for heat exchange 26,27 . The pinch analysis to develop the HIPSD process is performed on binary azeotropic systems using the temperature difference of the overhead vapor in the HP column and the bottom liquid in the LP column 28 . Their temperature profiles also depend on the operating pressure of the HP and LP columns.…”

AI-Based Geometry Recognition for Evaluating the Feasibility of Intensified Reaction and Separation Systems

“…Moreover, approximately 40% of the chemical industry’s total energy consumption is from distillation processes, which is a significant portion of the energy used by the industry. , Industrial energy consumption continues to rely on fossil fuels, which contribute most of the CO 2 emissions . Process intensification is considered an attractive solution for reducing the energy consumption of distillation processes through reduced equipment scale and efficiency outcomes. − …”