Multiobjective Optimization of a Four-Step Adsorption Process for Postcombustion CO₂ Capture Via Finite Volume Simulation

Abstract

In this study, we first report the development of a robust and efficient finite volume based adsorption process simulator, essential for rigorous optimization of a transient cyclic operation without resorting to any model reduction. We present a detailed algorithm for the common boundary conditions encountered in nonisothermal and nonisobaric adsorption process simulations. A comprehensive comparison of the high-resolution total variation diminishing (TVD) schemes, namely, van Leer and Superbee, with the weighted essentially nonoscillatory (WENO) finite volume scheme is performed, and trade-off plots are presented to identify the numerical scheme most suitable for attaining speed and accuracy at the same time. The simulator is then used to perform rigorous optimization of a four-step process for postcombustion CO2 capture from dry flue gas on zeolite 13X. The aim is to identify operating conditions at which the purity and recovery demands are met and to calculate corresponding energy consumption and process productivity. The purity–recovery and energy–productivity Paretos are generated using multiobjective optimization. It is shown that, for a strict vacuum swing adsorption (VSA) process, an evacuation pressure of 0.02 bar is required to satisfy regulatory demands of attaining a CO2 purity and recovery of 90%. It is also quantitatively shown that pressurizing the flue gas is detrimental to the energy consumption of process, although offering improvement in productivity.

CO2 capture in cation-exchanged metal–organic frameworks: Holistic modeling from molecular simulation to process optimization

“…In Table S1, the corresponding parameters for 13X Zeolite are provided, which is the current benchmark for post-combustion capture from dry flue gas. The equilibrium data for 13X used in our previous work (Haghpanah et al, 2013) were re-fitted with the similar constraints of saturation capacities implemented for rho-ZMOFs. The parameters (b 0 and ΔU) for N 2 at both sites were kept equal as 13X exhibits homogeneity towards N 2 , while those for CO 2 were different at two sites.…”

“…For the industrial scale deployment of adsorption-based CO 2 capture, both high-performance adsorbent and efficient process are necessary. To date, various adsorption cycles have been implemented for postcombustion CO 2 capture (Ridha and Webley, 2009;Agarwal et al, 2010;Haghpanah et al, 2013). From a four-step vacuum swing adsorption (VSA) process with light-product pressurization (LPP), it seems possible to achieve 95% purity and 90% CO 2 recovery for CO 2 capture in 13X while minimizing energy penalty and maximizing productivity (Haghpanah et al, 2013).…”

Energy and cost estimates for capturing CO2 from a dry flue gas using pressure/vacuum swing adsorption

“…For simulating our 4-step PVSA process, we used the model of Haghpanah et al (2013a). It assumes dual-site multicomponent Langmuir isotherms for the adsorption of CO 2 and N 2 on Zeochem 13X zeolite, and a linear driving force (LDF) model for the gas-to-solid mass transfer.…”

“…Because of the transient nature of a PVSA process, its performance can be assessed only at the cyclic steady state (CSS). To compute this CSS, we employ the single-column MATLAB-based simulation code developed by Haghpanah et al (2013a). For CO 2 purity and CO 2 recovery, we use the following.…”

Multi-objective optimisation using surrogate models for the design of VPSA systems

“…Over the years, many publications have considered the optimisation of VPSA systems (Haghpanah et al, 2013;Jiang et al, 2003;Nikoli et al, 2009;Nilchan & Pantelides, 1998;Krutka & Sjostrom, 2011;Ishibashi 20 et al, 1996;Krishnamurthy et al, 2014;Ribeiro et al, 2009Ribeiro et al, , 2008Da Silva et al, 1999). Usually, the governing hyperbolic/parabolic partial differential algebraic equations (PDAE) are simulated to cyclic steady state for each parameter set generated by the optimisation solver.…”