| Summary: |
Pressure Swing Adsorption (PSA) and Temperature Swing Adsorption (TSA) are well known separation techniques in chemical industries. These processes are composed by several columns to operate in cyclic continuous fashion: different steps or states are imposed to the columns to adsorb or separate a desired gas while the other column(s) are being regenerated. The cycle adsorption - regeneration is ordered in such a way to maximize unit productivity and product recovery and satisfying desired product specifications. The individual step-times are function of several feed conditions including pressure, temperature, flowrate and composition. The design of these separation processes is performed using constant feed conditions and dumper tanks can be employed to minimize the effect of small variations in feed conditions. When one or various feed conditions change over 20% with time, it is necessary to take some extra precautions or to directly modify the time of the steps in the different columns to keep product specifications. The application of large dumper tanks is not desired for small and middle size applications. In these cases, the only economically attractive solution to maximize productivity and recovery is on-line control strategies. In this project we will study on-line control strategies of multi-column PSA units and also extend this concept to other adsorption-based processes, like TSA. As an example of application of the results of theoretical research, specific instrumentation to operate and control a two-bed PSA unit will also be developed. Algorithms for a targeted multicomponent separation will be generated and solved together with process optimization to achieve the final goal of on-line process optimization for varying feed conditions. We will first study the case of equilibrium-based separations where simpler equations can be employed and after we will study more complex cases of kinetic-based separations. In this context we will focus on biogas  |
Summary
Pressure Swing Adsorption (PSA) and Temperature Swing Adsorption (TSA) are well known separation techniques in chemical industries. These processes are composed by several columns to operate in cyclic continuous fashion: different steps or states are imposed to the columns to adsorb or separate a desired gas while the other column(s) are being regenerated. The cycle adsorption - regeneration is ordered in such a way to maximize unit productivity and product recovery and satisfying desired product specifications. The individual step-times are function of several feed conditions including pressure, temperature, flowrate and composition. The design of these separation processes is performed using constant feed conditions and dumper tanks can be employed to minimize the effect of small variations in feed conditions. When one or various feed conditions change over 20% with time, it is necessary to take some extra precautions or to directly modify the time of the steps in the different columns to keep product specifications. The application of large dumper tanks is not desired for small and middle size applications. In these cases, the only economically attractive solution to maximize productivity and recovery is on-line control strategies. In this project we will study on-line control strategies of multi-column PSA units and also extend this concept to other adsorption-based processes, like TSA. As an example of application of the results of theoretical research, specific instrumentation to operate and control a two-bed PSA unit will also be developed. Algorithms for a targeted multicomponent separation will be generated and solved together with process optimization to achieve the final goal of on-line process optimization for varying feed conditions. We will first study the case of equilibrium-based separations where simpler equations can be employed and after we will study more complex cases of kinetic-based separations. In this context we will focus on biogas purification as a source of methane (binary separation CH4-CO2) in adsorbents such as zeolite 13X (equilibrium) and CMS 3K (kinetic-based separation). The second part of this project deals with new techniques for improving separations of diluted streams by adsorption processes. In this project we will study the Electric Swing Adsorption (ESA) process which may be an alternative to reduce energy consumption by direct application of energy to regenerate the adsorbent. We will also study this process for the case of equilibrium and kinetic-based control. Specific examples of mixtures to be studied within this project are CO2-N2 by zeolite 13X (equilibrium-based) and water removal (kinetic-based). |