Model Development, Validation, and Optimization of an MEA-Based Post-Combustion CO₂ Capture Process under Part-Load and Variable Capture Operations

Abstract

Existing power plants are frequently load-following due to increasing penetration of the renewables into the grid. For power plants integrated with CO 2 capture, optimal operation of the capture unit at part-load and variable capture conditions can be exploited to reduce the operating costs. This paper presents insights into the performance of a reference monoethanolamine (MEA)-based post-combustion CO 2 capture unit under steady-state part-load and variable capture operations. A rigorous plant-wide model for the capture unit is developed in the Institute for Design of Advanced Energy Systems computational platform. The contactor model is validated with the data from a wetted wall column (WWC) and two pilot plants. The plant-wide model is used for steady-state optimization under part-load operations and variable capture rates using flue gas similar to pulverized coal and natural gas-combined cycle power plants. Analysis on the performance of the reference rich/lean amine heat exchanger shows that the hot-end temperature approach can considerably vary under part-load operations for a given heat exchanger area. The study shows that if the plant is not optimally operated under part-load and variable capture operations, there can be a high penalty depending on the deviation of the liquid/gas flowrate with respect to its optimal value. This study shows that the optimal operation of an existing capture unit is crucial for minimizing the energy penalty under part-load and variable capture operations.

A modified electrolyte non‐random two‐liquid model with analytical expression for excess enthalpy: Application to theMEA‐H2O‐CO2system

“…10,42,72 Mass transfer rate-based simulation of absorber/stripper columns requires the bulk liquid equilibrium composition resulting from the aqueous phase reversible reactions. 5,9,74 Figure 7 shows the comparison of speciation plot as a function of CO 2 loading for 30 wt% MEA solution at 40 C with experimental data from Bottinger, 75 Jakobsen et al, 76 and Aspen model predictions from Hilliard. 47 The experimental NMR data from Jakobsen et al 76 are well represented by the model except a few experimental points especially those for x HCO3 À .…”

The IDAES process modeling framework and model library—Flexibility for process simulation and optimization

“…While the case study shown here is relatively simple, the IDAES-CMF has been applied to simulating and optimizing complex chemical and energy related processes, such as the removal of CO 2 from power plant flue gas. [38] The IDAES-CMF has also been applied to a range of other problem types, such as conceptual design and process intensification [39] and dynamic real-time optimization and control, [40] and non-linear robust optimization. [41] F I G U R E 1 8 Distribution of capital and operating cost with respect to the uncertainty considered in the kinetic parameters…”

Modeling and Bayesian Uncertainty Quantification of a Membrane-Assisted Chilled Ammonia Process for CO2 Capture

“…In post-combustion CO 2 capture, the flue gas is absorbed by the aqueous chemical solvent in an absorber near ambient conditions and is one of the leading technologies to reduce emissions from fossil-fired power plants. , The solvent is then regenerated using steam to create a product stream of high-purity CO 2 . While monoethanolamine (MEA) is the most matured, commercial solvent used for carbon capture, and has fast dynamic performance, , it has high energy penalty. , Aqueous ammonia is an alternative solvent with advantages including lower energy requirements for regeneration, high CO 2 loading, and absence of oxidative degradation as opposed to solvents such as MEA. , However, one key disadvantage of aqueous ammonia is the high volatility which results in ammonia slip from the absorber. Two typical methods, pursued separately and concurrently, are operating the absorber at low temperatures to reduce vapor pressure and inclusion of a water wash section to recover the solvent after the absorber.…”

“…5 While monoethanolamine (MEA) is the most matured, commercial solvent used for carbon capture, and has fast dynamic performance, 6,7 it has high energy penalty. 8,9 Aqueous ammonia is an alternative solvent with advantages including lower energy requirements for regeneration, high CO 2 loading, and absence of oxidative degradation as opposed to solvents such as MEA. 2,9 However, one key disadvantage of aqueous ammonia is the high volatility which results in ammonia slip from the absorber.…”