Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

Guido, Giorgia De; Langé, Stefano; Moioli, Stefania; Pellegrini, Laura

doi:10.1016/j.psep.2013.08.001

Cited by 63 publications

(50 citation statements)

References 36 publications

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“…Models capable of quantitatively describing the stochastic nature of nucleation in such systems would further enhance the ability of engineers to predict the risk of cryogenic solids formation. Unfortunately the models currently implemented in process simulators used across industry − are not able to match experimental SLE data reliably for even simple systems. To improve the thermodynamic models implemented in existing software tools and to develop and validate new models for stochastic nucleation, accurate and relevant measurements of solids formation and melting are required.…”

Section: Introductionmentioning

confidence: 99%

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

et al. 2017

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A specialized apparatus designed for visual measurements of solid-liquid equilibrium (SLE) and solid-liquid-vapor equilibrium (SLVE) was constructed and used to measure liquidus (melting) temperatures in binary mixtures of cyclohexane (C 6 H 12) and octadecane (C 18 H 38) across the entire range of composition and at pressures from about (0.004 to 5.3) MPa. A Peltier-cooled copper tip immersed in the liquid mixture was used to determine both freezing and melting temperatures by varying the temperature of the copper tip relative to the stirred, bulk liquid. With the bulk liquid held at the mixture's SLVE temperature, the induction time required to nucleate solid octadecane decreased exponentially as the subcooling of the copper tip increased, halving approximately every 0.25 K. At higher pressures, while the melting temperature of pure cyclohexane (cyC 6) increased by about 0.55 KMPa-1 , at x cyC6 = 0.5675 it increased by only 0.15 KMPa-1. The new data were compared with measurements reported in the literature, empirical correlations describing those literature data, and the predictions of models based on cubic equations of state (EOS), including the Peng-Robinson Advanced (PRA) EOS implemented in the software Multiflash. The best description of the data was achieved by adjusting the binary interaction parameter in the PRA model from 0 to-0.0324, which reduced the deviation of the SLVE data at the eutectic point (x cyC6 0.95) from (12.8 to-0.2) K. Although the accuracy of predictions made with the SLVE-tuned PRA EOS deteriorated slightly at pressures around 5 MPa, they were still as good as, or better, than the empirical correlations available for this system. Furthermore, the SLVE-tuned PRA EOS was more accurate at describing literature VLE data for this binary than the default PRA EOS, reducing the r.m.s. deviation in bubble temperature predictions from (6.7 to 0.67) K.

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Section: Introductionmentioning

confidence: 99%

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

et al. 2017

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“…For this reason, a reliable model based on thermodynamics (De Guido et al, 2014;Pellegrini et al, 2012a) chemical engineering research and design x x x ( 2 0 1 4 ) xxx-xxx is fundamental to well represent the absorption phenomenon occurring when dealing with PZ scrubbing. In particular, a correct description of properties of the absorbent solution, such as density and viscosity, and diffusivity of CO 2 in the used solvent are essential for modeling Pellegrini et al, 2012bPellegrini et al, , 2014.…”

Section: Introductionmentioning

confidence: 99%

Physical properties of PZ solution used as a solvent for CO2 removal

Moioli

Pellegrini

2015

Chemical Engineering Research and Design

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“…Cases with different levels of lignite pre-drying were analyzed. In the following, each simulated case is characterized by a letter (A or B) and by a number (10,20,30), where A and B refer to the specific CT at the topping cycle, as anticipated, while numbers indicate the residual moisture content (wt.%) in the dried lignite. Thus, the size of the IGCC system is determined by assuming that the mass flow rate exiting the CT is to be kept at a determined design value (665 kg/s).…”

Section: Simulations Of Gasification and Power Stationsmentioning

confidence: 99%

“…The commercial simulator ASPEN Plus ® was used as a basis for simulations of the AGR units, because of its capability of being user customized. A reliable model for both thermodynamics and mass transfer with reactions is fundamental for a correct design of the process . As for thermodynamics, vapor–liquid equilibrium is influenced by the chemical reactions occurring in the liquid phase and involving the presence of ionic species.…”

Section: Simulation Environments Assumptions and Considerationsmentioning

confidence: 99%

Lignite-fired air-blown IGCC systems with pre-combustion CO₂capture

Giuffrida

Moioli

Romano

et al. 2016

Int. J. Energy Res.

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SUMMARYDetailed analyses based on mass and energy balances of lignite-fired air-blown gasification-based combined cycles with CO 2 pre-combustion capture are presented and discussed in this work. The thermodynamic assessment is carried out with a proprietary code integrated with Aspen Plus ® to carefully simulate the selective removal of both H 2 S and CO 2 in the acid gas removal station. The work focuses on power plants with two combustion turbines, with lower and higher turbine inlet temperatures, respectively, as topping cycle. A high-moisture lignite, partially dried before feeding the air-blown gasification system, is used as fuel input. Because the raw lignite presents a very low amount of sulfur, a particular technique consisting of an acid gas recycle to the absorber, is adopted to fulfill the requirements related to the presence of H 2 S in the stream to the Claus plant and in the CO 2 -rich stream to storage. Despite the operation of the H 2 S removal section representing a significant issue, the impact on the performance of the power plant is limited. The calculations show that a significant lignite pre-drying is necessary to achieve higher efficiency in case of CO 2 capture. In particular, considering a wide range (10-30 wt.%) of residual moisture in the dried lignite, higher heating value (HHV) efficiency presents a decreasing trend, with maximum values of 35.15% and 37.12% depending on the type of the combustion turbine, even though the higher the residual moisture in the dried coal, the lower the extraction of steam from the heat recovery steam cycle. On the other hand, introducing the specific primary energy consumption for CO 2 avoided (SPECCA) as a measure of the energy cost related to CO 2 capture, lower values were predicted when gasifying dried lignite with higher residual moisture content. In particular, a SPECCA value as low as 2.69 MJ/kg CO2 was calculated when gasifying lignite with the highest (30 wt.%) residual moisture content in a power plant with the advanced combustion turbine.Ultimately, focusing on the power plants with the advanced combustion turbine, air-blown gasification of lignite brings about a reduction in HHV efficiency equal to almost 1.5 to 2.8 percentage points, depending on the residual moisture in the dried lignite, if compared with similar cases where bituminous coal is used as fuel input.

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Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

Cited by 63 publications

References 36 publications

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

Physical properties of PZ solution used as a solvent for CO2 removal

Lignite-fired air-blown IGCC systems with pre-combustion CO₂capture

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Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

Cited by 63 publications

References 36 publications

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

Visual Measurements of Solid–Liquid Equilibria and Induction Times for Cyclohexane + Octadecane Mixtures at Pressures to 5 MPa

Physical properties of PZ solution used as a solvent for CO2 removal

Lignite-fired air-blown IGCC systems with pre-combustion CO2capture

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Product

Resources

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Lignite-fired air-blown IGCC systems with pre-combustion CO₂capture