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Technoeconomic and Dynamical Analysis of a CO2 Capture Pilot-Scale Plant Using Ionic Liquids

Valencia-Marquez, Darinel, Flores-Tlacuahuac, Antonio, Ricardez-Sandoval, Luis
Industrial & Engineering Chemistry Research 2015 v.54 no.45 pp. 11360-11370
absorption, carbon dioxide, carbon sequestration, chemical degradation, energy, ethanolamine, flue gas, greenhouse gas emissions, ionic liquids, multi-criteria decision making, operating costs, power plants, prices, solubility, thermal stability
Carbon capture has been recognized as an attractive alternative to reduce CO₂ emissions. The most feasible technology that can be developed at a commercial-scale in a short-term period is CO₂ capture by absorption since it is an end-pipe technology that can be installed in existing coal-based power plants and will not require retrofit of the power plant. The most studied CO₂ capture process is absorption using monoethanolamine (MEA) and represents the benchmark solvent because of the favorable properties it has shown such as fast kinetics, high absorption capacity, good solubility in water, and low price. On the other hand, this solvent is susceptible to thermal and chemical degradation, and it is also corrosive. Nevertheless, the main drawback of this solvent is the energy consumption needed for solvent recovery (almost >90% of the plant’s operating cost). Ionic liquids (IL) are new alternative solvents for CO₂ capture. Experimental results have shown that IL feature chemical and thermal stability, and good CO₂ absorption capacity. In this work, a theoretical IL is used as physical solvent for developing a new flow-sheet of a CO₂ capture plant. A techno-economic analysis was carried out to evaluate the feasibility of the proposed design. The results show that the IL-based plant features lower energy demand compared to a traditional MEA-based plant. Moreover, the dynamic analysis performed in this study provides insight on the degree of nonlinearity and the dynamics of the process, which are essential tools to design suitable control schemes. The results show that the plant can accommodate perturbations in the flue gas flow rate up to ±10% while meeting CO₂ recovery and purity targets.