scholarly journals Optimization and analysis of pressure swing adsorption process for oxygen production from air under uncertainty

2020 ◽  
Vol 26 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Evgeny Akulinin ◽  
Oleg Golubyatnikov ◽  
Dmitry Dvoretsky ◽  
Stanislav Dvoretsky
Keyword(s):  
Pressure Swing Adsorption ◽  
Gas Flow ◽  
Optimization Problem ◽  
Air Separation ◽  
Interval Uncertainty ◽  
Problem Solution ◽  
Resource Saving ◽  
Heat And Mass Exchange ◽  
Atmospheric Air ◽  
Pressure Swing

Pressure swing adsorption (PSA) units are widely used for atmospheric air separation and oxygen concentration. However, the efficiency of such installations is reduced due to accidental changes in the characteristics of the atmospheric air to be separated. The article formulates and solves the problem of optimizing the regimes of operation of PSA units with zeolite adsorbent 13X, according to the criterion of oxygen recovery rate in the conditions of interval uncertainty of composition, temperature and pressure of atmospheric air. The optimization problem also takes into account the fulfillment of the requirements on purity of oxygen, productivity of the unit and resource saving of granulated adsorbent from granule abrasion. It is proposed to provide adsorbent saving by limiting the speed of incoming flow in the frontal layer of the adsorbent by means of "soft" stepwise change of the degree of opening of control inlet and outlet valves of the unit. The problem (including the search for time change programs for the degree of opening of control valves) was solved with the use of the developed mathematical model of cyclic heat- and mass exchange processes of adsorption-desorption in a PSA unit and a heuristic iterative algorithm. The comparative analysis of the results of the optimization problem solution, with and without taking into account the constraint on the gas flow velocity in the frontal layer of the adsorbent, is carried out. The influence of the specified requirements for the performance of the PSA unit and the purity of oxygen on the degree of its recovery has been studied.

scholarly journals Chemical Plant Utility – Nitrogen System Design

2021 ◽  
Vol 9 (11) ◽  
pp. 1560-1567
Author(s):  
Prasad J. Parulekar
Keyword(s):  
High Purity ◽  
Pressure Swing Adsorption ◽  
Membrane Separation ◽  
Hollow Fibre ◽  
Air Separation ◽  
Separation Technique ◽  
Flow Diagram ◽  
Efficient Technology ◽  
Atmospheric Air ◽  
Pressure Swing

Abstract: The study is been conducted to understand the different techniques to separate nitrogen from atmospheric air. Separation of nitrogen takes place by following techniques: Cryogenic air separation, Pressure swing adsorption and Membrane separation technique. Cryogenic air separation operates at a very low temperature, which uses the principle of rectification to separate nitrogen at a very high purity (99.999%). Pressure swing adsorption rely on the fact that higher the pressure, more the gas is adsorbed which results in high purity (95-99.99%) of nitrogen. Membrane separation technology is the process that uses hollow fibre membranes to separate the constituent gases in air, which gives the purity in the range of 93%-99.5%. After the comparative study, it is understood that membrane separation technique is the most efficient technology based on the cost, purity, flexibility in terms of adjusting the purity, maintenance, availability; it operates without heating and therefore uses less energy than conventional thermal separation processes. Different step designs of membrane separation techniques are discussed. A Process Flow Diagram and Piping Instrumentation Diagram is been added for single step membrane separation technique. Keywords: Atmospheric air, nitrogen, Cryogenic air separation, Pressure swing adsorption, Membrane separation technique.

Numerical Analysis and Optimization of Oxygen Separation from Air via Pressure Swing Adsorption

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Seyyed M. Ghoreishi ◽  
Z. Hoseini Dastgerdi ◽  
Ali A Dadkhah
Keyword(s):  
Time Constant ◽  
Pressure Swing Adsorption ◽  
Separation Efficiency ◽  
Optimization Procedure ◽  
Air Separation ◽  
Oxygen Separation ◽  
13X Zeolite ◽  
Oxygen Generation ◽  
Pressure Swing ◽  
Energy And Momentum

A pressure swing adsorption air separation process in a commercial aircraft using 13X zeolite with a more complex cycle than the classic Skarstrom was simulated via a predictive dynamic model to evaluate and optimize oxygen generation system. The coupled mass, energy, and momentum differential equations were discretized using the implicit central finite-difference technique and the obtained equations were solved by Newton-Raphson method. The validated model in conjunction with an optimization procedure (Successive Quadratic Programming) was utilized to investigate the oxygen separation efficiency as a function of β (ratio between the bed time constant and the particle diffusion time constant), Cfp (purge orifice coefficient), θcycle (cycle time), Cff (feed valve), Cfe (exhaust valve) and pH* (high pressure operation). A set of optimum values (β=150, Cfp=0.7, θcycle=1.5, Cff=31, Cfe=52 and pH*=3.8) was obtained and recommended to achieve maximum recovery (0.26) at 98% purity.

scholarly journals An Improved Method to Calculate the Conservation of Mass in the Simulation of Rapid Pressurization Depressurization in a Packed Bed

2008 ◽  
Vol 2 (1) ◽  
pp. 30
Author(s):  
Thomas S.Y Chong ◽  
William R. Paterson ◽  
David M. Scott
Keyword(s):  
Differential Equations ◽  
Pressure Swing Adsorption ◽  
Packed Bed ◽  
Air Separation ◽  
Simple Problem ◽  
Improved Method ◽  
Conservation Of Mass ◽  
Rapid Pressure Swing Adsorption ◽  
Pressure Swing ◽  
Rapid Pressure

The work described here forms part of a project to model rapid pressure swing adsorption (RPSA), which is a single-bed process used for air separation. We have earlier identified a form of model and boundary conditions for an axially dispersed plug flow model that conserves mass. We solve the RPSA models numerically by spatially discretizing the partial differential equations to a system of ordinary differential equations (ODEs), which are then integrated over time. Although the formulation of our models conserves mass, our numerical simulations, however, do not perfectly conserve mass because of discretization error and rounding error. The discrepancy in the conservation of mass is computed as a guide to the numerical accuracy of the calculations. The computation of the conservation error requires the evaluation of time integrals of molar flowrates in and out of the bed. Since the velocity at the feed end of the bed changes rapidly with time, the application of quadrature to evaluate the time integrals does not provide the accuracy required. In this paper, the inadequacy is demonstrated using a simple problem, i.e. pressurization and depressurization into a non-adsorptive bed. An improved method is proposed. By transforming equations involving time integrals into ODEs, excellent accuracy is obtained. Further, this transformation minimizes the number of decision parameters that need to be specified by the users of the computer programs. Keywords: rapid pressure swing adsorption, modelling and simulation, packed bed.

Analysis and Optimization of a Pressure-Swing Adsorption Process for Air Separation

2005 ◽  
Vol 31 (6) ◽  
pp. 441-449 ◽  
Author(s):  
Masatoshi Yoshida ◽  
Pathiphon Koompai ◽  
Yoshiyuki Yamashita ◽  
Shigeru Matsumoto
Keyword(s):  
Pressure Swing Adsorption ◽  
Adsorption Process ◽  
Air Separation ◽  
Pressure Swing

Methodology for creating and studying units for adsorption separation and purification of gas mixtures

2021 ◽  
Vol 6 (3) ◽  
pp. 179-203
Author(s):  
Evgeny I. Akulinin ◽  
Oleg O. Golubyatnikov ◽  
Dmitry S. Dvoretsky ◽  
Stanislav I. Dvoretsky
Keyword(s):  
Pressure Swing Adsorption ◽  
Time Pressure ◽  
Gas Mixtures ◽  
Separation And Purification ◽  
Resource Saving ◽  
Software Complex ◽  
Technological Processes ◽  
Operating Variables ◽  
Separation Of Gas Mixtures ◽  
Pressure Swing

Methodology for creating and studying technological processes and resource-saving units for adsorption separation and purification of gas mixtures (atmospheric air, synthesis gas) with cyclically changing pressure was developed. A problem-oriented hardware-software complex designed to study the properties and operation regimes of units for adsorption separation of gas mixtures and extraction of product gases was created. The complex can also be used to prepare initial data for the design of industrial units for separation and purification of gas mixtures by the method of pressure swing adsorption. The coefficients of mass transfer and mass conductivity in the adsorbent were calculated for the processes during adsorption and desorption of the adsorptive (nitrogen, oxygen, carbon dioxide and monoxide, hydrogen) using experimentally obtained kinetic curves, and the adequacy of mathematical models was established. Using the hardware-software complex, experimental and numerical studies of technological processes for extraction of product gases (oxygen and hydrogen with a purity of 45 to 95.5 vol.%, from 99 to 99.99 vol.%, respectively), the effect of mass and heat exchange processes and operating variables (“adsorption-desorption” cycle time, pressure at the adsorption step), disturbing influences (composition and temperature of the initial gas mixture) on the performance indicators of the pressure swing adsorption unit were carried out.

scholarly journals Air Separation Characteristics of Pressure Swing Adsorption Apparatus using Molecular Sieving Carbon.

1993 ◽  
Vol 19 (2) ◽  
pp. 162-168
Author(s):  
Chisato Marumo ◽  
Eiji Hayata ◽  
Niro Shiomi ◽  
Kenji Kojima ◽  
Fujio Watanabe ◽  
...  
Keyword(s):  
Pressure Swing Adsorption ◽  
Air Separation ◽  
Pressure Swing ◽  
Molecular Sieving
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