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

Abstract

Aprotic heterocyclic anion ionic liquids (AHA ILs) have received significant recent attention as potential absorbents for next-generation carbon capture processes. In this paper, we describe a rate-based model of an AHA IL-based carbon capture process. We use the model to perform economic optimization, minimizing a total cost function (annual operating cost plus annualized capital cost). Process-level decisions, including equipment design and operating parameters, are considered simultaneously with the material-level decision of the CO2 reactive absorption enthalpy in the AHA IL being a tunable molecular parameter. We study how the optimal design changes with flexible flue gas compositions, with a focus on cases arising in the context of partial oxy-combustion. We also study the variation in the optimal design as the CO2 capture level changes. Flexibility in this regard is important as power plants increasingly need to account for time-varying power demand due to the market penetration of variable renewable energy sources such as wind and solar power.

Improvement of Co2 Capture Processes by Tailoring the Reaction Enthalpy of Aprotic N-Heterocyclic Anion-Based Ionic Liquids

“…On the other hand, since more exothermic CO 2 -IL reactions are harder to reverse, the efficiency of regeneration stage is reduced, increasing IL and energy demands [30]. As a result, optimum performances were obtained in the reaction enthalpy range between − 43 and − 54 kJ/mol, very similar to those reported in literature studies (optimum around − 49 kJ/mol) [22,24]. This range widens the variety of possibilities when synthesizing new suitable AHA-ILs for these CO 2 capture systems, being able to select those presenting the most suitable enthalpy according to the operating conditions.…”

“…Indeed, some AHA-ILs based on imide anions were recently found to even reach superior 2:1 absorption capacity by the adequate combination of chemical and physical absorption [21]. Thus, the enthalpy of CO 2 +AHA-IL reaction plays a main role in process performance, being demonstrated that increasing the reaction exothermicity can enhance solvent and energy requirements, consequently reducing overall process costs [13,[22][23][24].…”

Energy, Cost, and Environmental Assessments of Methanol Production via Electrochemical Reduction of CO2 from Biosyngas

“…For product separation, the costs of PSA and distillation were calculated using the factorial method demonstrated in the literature with a capacity-scaling factor of 0.7. , In the stand-alone system, the cost for CO 2 capture in IL was obtained by surveying the literature, which is in the range of 20–70 €/ton-CO 2 . , In this analysis, the cost was assumed to be 50 €/ton-CO 2 . For the integrated systems, CO 2 removal belongs to the upstream producer, i.e., the “gas cleaning” unit following the biomass gasifier in the gasification chain, and this removal unit cannot be avoided in the gasification chain, no matter if the removed CO 2 will be used or not.…”

Equation-Oriented Optimization Applied to the Optimal Design of Carbon Capture Plants Using Rigorous Models

“…They have shown that their approach allows for optimization using gradient-based methods for large-scale optimization problems. Seo et al 28,29 have employed the pseudo-transient continuation method in the equation-oriented environment of gPROMS to address the optimal design of CO 2 capture processes using ionic liquids. Although significant progress has been made in this area, there are still challenges in the optimal design of CO 2 capture plants.…”