Rate-Based Process Optimization and Sensitivity Analysis for Ionic-Liquid-Based Post-Combustion Carbon Capture

Abstract

Ionic liquids (ILs) are a promising class of absorbents for next-generation carbon-capture processes. In particular, aprotic heterocyclic anion ILs (AHAs) have received significant attention due to their ability to chemically absorb CO2 without a significant increase in viscosity. The development of process modeling and mathematical optimization approaches for AHA-based carbon-capture processes is essential for the evaluation of economic feasibility before industrial implementation. In this paper, we use a pseudo-transient modeling approach that enables the robust simulation and optimization of the large-scale process flowsheet. A Langmuir-type model that incorporates both the chemical and physical uptake of CO2 is used to describe the equilibrium absorption of CO2 by the IL. A rigorous rate-based model for the absorption column is employed to account for the effect of reversible chemical reactions on mass transfer. The models are then used to carry out economic optimization of a prototypical IL-based carbon-capture process. A sensitivity analysis of important IL properties is provided, revealing the key factors that affect IL choice. Finally, a comparison to an advanced amine-based process is briefly discussed.

Economic Optimization of Carbon Capture Processes Using Ionic Liquids: Toward Flexibility in Capture Rate and Feed Composition

“…A further discussion of the impact of water absorption on the process performance has been presented by Hong et al . and Seo et al With these assumptions, the vapor phase components are N 2 , O 2 , and CO 2 .…”

“…Motivated by the above, we recently presented a rate-based model and performed economic cost optimization for an AHA IL-based CO 2 capture process . We used the pseudo-transient modeling and optimization framework proposed by Pattison and Baldea, later extended to rate-based column models, to solve and optimize the complex flowsheet model.…”

Deciphering the Sustainability of an Ionic Liquid-Based BTX Harvesting Process from Energetic, Environmental, and Economic Perspectives

“…Some authors − agree that bulk ionic liquids could be sold at about €10–30 kg –1 . However, considering the price increase of the raw materials for preparing the ILs, a selling price of €35 kg –1 for the [EMIM]­[Tf 2 N] IL is assumed, and it is rational according to the experience reported by Seo et al, who thought that the price of the ILs is $10–40 kg –1 at large scales. Meanwhile, an exchange rate of 1.11 is assumed between the Euro and USD.…”

Integrated ionic liquid and rate‐based absorption process design for gas separation: Global optimization using hybrid models

“…Note that for a given solvent, the optimization of rigorous rate-based absorption processes has been studied. 35 However, no one has used the rate-based process model for integrated solvent and absorption process design. The main reason is that such design problems usually lead to challenging mixed-integer nonlinear programming (MINLP) problems, especially when complex thermodynamic models are used.…”

“…Note that for a given solvent, the optimization of rigorous rate‐based absorption processes has been studied 35 . However, no one has used the rate‐based process model for integrated solvent and absorption process design.…”