Optimization of Pressure-Swing Distillation by Evolutionary Techniques: Separation of Ethanol-Water and Acetonitrile-Water Mixtures

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Adjay Sagar S ◽  
Imran Rahman
Keyword(s):  
Complete Separation ◽  
Optimal Number ◽  
Reflux Ratio ◽  
Temperature Profiles ◽  
Total Cost ◽  
Search Spaces ◽  
Pressure Sensitive ◽  
Azeotropic Mixtures ◽  
Pressure Swing ◽  
Pressure Swing Distillation

Abstract Complete separation can be achieved in selective homogeneous azeotropic mixtures by exploiting the pressure sensitive nature of the system. In the present work the optimal number of trays, feed location and reflux ratio for sequential column systems encountered in continuous pressure swing distillation (PSD) have been determined by use of two evolutionary techniques. Two industrially relevant systems: ethanol-water and acetonitrile-water have been considered. The Napthali-Sandholm model is solved to obtain the concentration and temperature profiles. The objective is to minimize the total cost using Genetic Algorithm (GA) and Differential Evolution (DE) for the two azeotropic systems. The techniques offer attractive features like applicability to discontinuous and non-differentiable search spaces.

scholarly journals Synthesis of Ternary Homogeneous Azeotropic Distillation Sequences: 2. Flowsheet Identification

2013 ◽  
Vol 13 (1) ◽  
pp. 43
Author(s):  
Sutijan Sutijan ◽  
Megan Jobson ◽  
Robin Smith
Keyword(s):  
Classification System ◽  
Ternary Mixture ◽  
Azeotropic Distillation ◽  
Ternary Mixtures ◽  
Boundary Crossing ◽  
New Classification ◽  
Azeotropic Mixtures ◽  
Systematic Methodology ◽  
Pressure Swing ◽  
Pressure Swing Distillation

This paper presents a systematic methodology for flowsheet generation for separating binary azeotropic mixtures using homogeneous azeotropic distillation. A new classification system for ternary mixtures using ‘standard distillation line maps’ defined in Sutijan et al. (2012) is employed. The new characterisation system is able to link candidate entrainers to flowsheet structures which can facilitate the separation. The sequences considered include pressure-swing distillation, two and three-column flowsheets with or without boundary crossing and the use of single and double-feed columns. For a given ternary mixture, suitable flowsheet structures that can facilitate the separation can be automatically identified. The method is illustrated using examples.

scholarly journals Influence of the main operating parameters on the DRPSA process design based on the equilibrium theory

Adsorption ◽  
2020 ◽  
Author(s):  
Ester Rossi ◽  
Giuseppe Storti ◽  
Renato Rota
Keyword(s):  
Pressure Swing Adsorption ◽  
Degrees Of Freedom ◽  
Pressure Ratio ◽  
Complete Separation ◽  
Operating Conditions ◽  
Equilibrium Theory ◽  
Design Parameters ◽  
Reflux Ratio ◽  
Gaseous Mixtures ◽  
Pressure Swing

Abstract Among the adsorption-based separation processes for gaseous mixtures, those exploiting pressure variations, so-called Pressure Swing Adsorption (PSA) processes, are the most popular. In this work, we focus on the specific PSA configuration known as Dual Reflux-Pressure Swing Adsorption (DR-PSA) given its ability to achieve sharp separations. In the case of binary mixtures, an analytical approach based on Equilibrium Theory has been proposed to identify the operating conditions for complete separation under the assumption of linear isotherms. This same approach is not available when the separation is not complete. Accordingly, in this work we study the features of non-complete separations by solving numerically a general DR-PSA model with parameter values suitable to approach equilibrium conditions (no mass transport resistances, no axial mixing, isothermal conditions and no pressure drop), thus reproducing the analytical solution when complete separations are examined. Even for non-complete separations, triangularly shaped regions at constant purity can be identified on a plane whose axes correspond to suitable design parameters. Moreover, we found a general indication on how to select the lateral feed injection position to limit the loss in product purities when complete separation is not established, whatever is the composition of the feeding mixture. Finally, a sensitivity analysis with respect to pressure ratio, light reflux ratio and heavy product flowrate is proposed in order to assess how to recover product purities according to the specific degrees of freedom of a DR-PSA apparatus.

scholarly journals Process Simulation of the Separation of Aqueous Acetonitrile Solution by Pressure Swing Distillation

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 409 ◽  
Author(s):  
Jing Li ◽  
Keliang Wang ◽  
Minglei Lian ◽  
Zhi Li ◽  
Tingzhao Du
Keyword(s):  
Acetonitrile Solution ◽  
Optimum Process ◽  
Total Annual Cost ◽  
Heat Integration ◽  
Reflux Ratio ◽  
Water Mixture ◽  
Aqueous Acetonitrile ◽  
Design Variables ◽  
Pressure Swing ◽  
Pressure Swing Distillation

The separation of aqueous acetonitrile solution by pressure swing distillation (PSD) was simulated and optimized through Aspen Plus software. The distillation sequence of the low pressure column (LPC) and high pressure column (HPC) was determined with a phase diagram. The pressures of the two columns were set to 1 and 4 atm, respectively. Total annual cost (TAC) was considered as the objective function, and design variables, such as the tray number, the reflux ratio, and the feeding position, were optimized. The optimum process parameters were obtained. For the reduction of energy consumption, the PSD with full-heat integration was designed. The TAC of this method is lower by 32.39% of that of the PSD without heat integration. Therefore, it is more economical to separate acetonitrile and water mixture by PSD with full-heat integration, which provides technical support for the separation design of such azeotropes.

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