A methodology for the heuristic optimization of solvent-based CO2 capture processes when applied to new flue gas compositions: A case study of the Chilled Ammonia Process for capture in cement plants

Assessment on the Application of Facilitated Transport Membranes in Cement Plants for CO2 Capture

“…In recent years, several research projects have explored CCS in the cement industry and solutions for both retrofit of existing plants or implementation in new building have been investigated extensively [7][8][9]. Several separation processes are proposed with a wide range of results in terms of techno-economic performance as, for example, absorption with liquid solvents absorption [7,[10][11][12][13], solid adsorbents [14], calcium looping [7,8,15,16] and molten carbonate fuel cells [17].…”

Density and Viscosity of Aqueous (Ammonia + Carbon Dioxide) Solutions at Atmospheric Pressure and Temperatures between 278.15 and 318.15 K

“…11 Accordingly, the current CAP implementation limits NH 3 emissions and avoids solid formation by carrying out the absorption of CO 2 at temperatures between 278 and 318 K using aqueous solutions with apparent NH 3 concentrations ranging between 4 and 10 mol NH 3 kg H 2 O −1 , and limiting the apparent CO 2 concentration in solution to CO 2 loadings between 0.25 and up to 0.65 mol CO 2 mol H 2 O −1 or below, depending on the combination of absorbent temperature and NH 3 concentration. 12 The sizing and design of the CO 2 absorption column, one of the main contributors to the investment costs of a CO 2 capture plant, 13 requires accurate modeling of the rates of mass and heat transfer, which depend on the physicochemical properties of the liquid absorbent and on the hydrodynamics within the vapor−liquid contactor. The hydrodynamic conditions within the CO 2 absorber are strongly influenced by the density and by the transport properties of the aqueous solution, 14,15 among which viscosity and CO 2 diffusivity have the greatest impact.…”

“…The reactions in the liquid phase of the CO 2 −NH 3 −H 2 O system consist not only of instantaneous reactions that require the transfer of a proton, but also of kinetically controlled reactions the rate of which decreases with decreasing temperature. 12 As a consequence, at lower temper- atures, the time scale of the density measurements, that is, of the order of minutes, does not allow the liquid sample to reach its equilibrium speciation, which would require hours at 278.15 K. 27 Therefore, samples with the same apparent composition, that is, with the same overall concentration of CO 2 and NH 3 , may have different true concentrations of molecular and ionic species during the density measurement depending on the sample storage history. Nevertheless, all reported density measurements correspond to samples stored for a similar time after preparation in order to minimize uncertainties in the measurement.…”

“…On the other hand, the main challenge for the application of aqueous ammonia solutions in CO 2 capture processes is the control and limitation of NH 3 loss and emissions to the environment as a consequence of the higher equilibrium NH 3 vapor pressure in comparison with most amines. , To limit NH 3 emissions in the exiting flue gas, Alstom patented the chilled ammonia process (CAP), in which CO 2 is captured by means of an aqueous ammonia solution previously refrigerated to temperatures below ambient, that is, between 273 and 293 K. However, such low temperatures can lead to solid formation in the absorption process . Accordingly, the current CAP implementation limits NH 3 emissions and avoids solid formation by carrying out the absorption of CO 2 at temperatures between 278 and 318 K using aqueous solutions with apparent NH 3 concentrations ranging between 4 and 10 mol NH 3 kg H 2 O –1 , and limiting the apparent CO 2 concentration in solution to CO 2 loadings between 0.25 and up to 0.65 mol CO 2 mol H 2 O –1 or below, depending on the combination of absorbent temperature and NH 3 concentration . The sizing and design of the CO 2 absorption column, one of the main contributors to the investment costs of a CO 2 capture plant, requires accurate modeling of the rates of mass and heat transfer, which depend on the physicochemical properties of the liquid absorbent and on the hydrodynamics within the vapor–liquid contactor.…”

“…by Peŕez-Calvo et al12 using experimental density values available in the literature for the liquid binary mixture NH 3 − H 2 O.16−19 The molar fraction of apparent NH 3 in the binary mixture with water, x̂N H 3 0 , can be computed from the molality of apparent NH 3 , b ̂NH 3 [mol NH 3 kg H 2 O −1 ], as follows:…”