Linear Driving Force Approximations as Predictive Models for Reactive Sorption

2019 ◽  
Vol 8 (8) ◽  
pp. 1900718
Author(s):  
Sara Azzam ◽  
Dante A. Simonetti
Keyword(s):  
Predictive Models ◽  
Driving Force ◽  
Linear Driving Force

Linear Driving Force Model in Carbon Dioxide Capture by Adsorption

2016 ◽  
Vol 830 ◽  
pp. 38-45 ◽  
Author(s):  
Leonardo Hadlich de Oliveira ◽  
Joziane Gimenes Meneguin ◽  
Edson Antonio da Silva ◽  
Maria Angélica Simões Dornellas de Barros ◽  
Pedro Augusto Arroyo ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Breakthrough Curve ◽  
Driving Force ◽  
Fixed Bed ◽  
Isotherm Models ◽  
Force Model ◽  
Transfer Resistance ◽  
Linear Driving Force

In this work, experimental data of CO2 capture by adsorption was determined gravimetrically, at 30 °C and pressures up to 40 bar, and in a fixed bed unit at 20 bar, using NaY as adsorbent. Langmuir, Sips and Tóth isotherm models were used to correlate the equilibrium data. Sips and Tóth models were best fitted allowing estimate the maximum CO2 adsorbed amount. The breakthrough curve was modeled using Linear Driving Force (LDF) and Thomas models. The LDF model represented better the CO2 breakthrough curve than Thomas model. The mass transfer resistance in NaY micropores can be assumed as the limiting step for CO2 adsorption in fixed bed, since the intraparticle mass transfer coefficient of LDF model was smaller than the experimental overall volumetric mass transfer coefficient, although external film resistance is not negligible.

Combined Experimental and Numerical Investigation of Linear Driving Force Kinetics in Small Activated Carbon Beds

2019 ◽  
Vol 58 (36) ◽  
pp. 16978-16988
Author(s):  
Samuel G. A. Wood ◽  
Nilanjan Chakraborty ◽  
Martin W. Smith ◽  
Mark J. Summers
Keyword(s):  
Activated Carbon ◽  
Numerical Investigation ◽  
Driving Force ◽  
Linear Driving Force

Use of the Linear Driving Force Approximation in Adsorption Heat Pump and Chiller Modeling

2009 ◽  
Author(s):  
Alex Raymond ◽  
Srinivas Garimella
Keyword(s):  
Mass Transfer ◽  
Driving Force ◽  
Waste Heat ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Activated Carbon Fiber ◽  
Fickian Diffusion ◽  
Half Cycle ◽  
Linear Driving Force ◽  
Adsorption Heat Pump

Adsorption heat pumps and chillers can utilize solar or waste heat to provide space conditioning, process heating or cooling, or energy storage. In these devices, accurate modeling of intraparticle adsorbate mass transfer is an important part of predicting overall performance. The linear driving force (LDF) approximation is often used for modeling intraparticle mass transfer in place of the more detailed Fickian diffusion (FD) equation for its computational simplicity. This paper directly compares the adsorbate contents predicted by the conventional LDF approximation, an empirical LDF approximation proposed by El-Sharkawy et al. [1], and the FD equations for cylindrical adsorbent fibers such as activated carbon fiber (ACF). The conditions under which the LDFs agree with the FD equation are then evaluated. It is shown that for a given working pair, agreement between the LDF and FD equations is affected by the diffusivity, particle radius, half-cycle time, initial adsorbate content, and equilibrium adsorbate content. The maximum possible error in adsorbate content predicted by the LDF approximation compared with the FD solution is then calculated for the ACF (A-20)-ethanol working pair. Although the maximum error will be different for other cases, the technique used in this paper can be reproduced to determine the greatest possible LDF error for any working pair.

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