Kinetics study for sodium transformation in supercritical water gasification of Zhundong coal

Zhang, Deming; Guo, Liejin; Zhao, Jiuyun; Cao, Wen; Wang, Runyu; Wei, Wenwen; Chen, Jia

doi:10.1016/j.ijhydene.2017.12.011

Cited by 44 publications

(4 citation statements)

References 37 publications

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“…One way of producing hydrogen is the so-called coal and supercritical water gasification, which is to convert the coal into the hydrogen-rich gas mixture in the supercritical water atmosphere. The molecular dynamic simulation, the experimental studies, , and the kinetics study of the coal and supercritical water gasification have been carried out recently. At temperature 923 K and pressure 25 MPa, the mixture contains <28% H 2 , <12% CO 2 , and >60% water vapor (in mole fractions).…”

Section: Introductionmentioning

confidence: 99%

Density Data of Two (H₂ + CO₂) Mixtures and a (H₂ + CO₂ + CH₄) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Cheng

Shang

et al. 2019

J. Chem. Eng. Data

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The PVT properties of the (H2 + CO2) mixtures and the (H2 + CO2 + CH4) mixtures in the supercritical region of water are significant for making full use of the gas mixtures in the coal and supercritical water gasification. We report PVT measurements of the (0.6005 H2 + 0.3995 CO2), (0.6992 H2 + 0.3008 CO2), and (0.6026 H2 + 0.1948 CO2 + 0.2026 CH4) mixtures (all in mole fractions) at temperature 673 K and pressures of (0.5 to 25) MPa, measured by a modified Burnett method. The upper bounds of the expanded uncertainties at 95% confidence are 0.2 K for temperature, 0.015·p for pressure, and 0.008·ρ for density. The density data were compared with those predicted using the GERG-2008 equation of state. The deviations between the calculated and experimental data are not more than 0.021·ρ. Furthermore, the densities were found in accordance with the weighted average of the components’ existing equations of state using their mole fractions within 0.0076·ρ for all of the mixtures in this work. The second and third virial coefficients were determined at temperature 673 K for hydrogen and all of the mixtures investigated.

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Section: Introductionmentioning

confidence: 99%

Density Data of Two (H₂ + CO₂) Mixtures and a (H₂ + CO₂ + CH₄) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Cheng

Shang

et al. 2019

J. Chem. Eng. Data

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“…In spite of the debatable conclusion, the chemisorption of H 2 O on the carbon structure could be boosted in SCW as high pressure facilitates similar adsorption and stimulates gasification subsequently. It is necessary to mention that in raw Zhundong coal, the most alkali metal is water soluble (up to 61%), while only 27% alkali metal remains water soluble after 20 min of SCWG at 650 °C . After switching purge gas and hold samples in pure nitrogen, negligible weight loss is observed by comparing point B and point C (−0.05 and −0.04% for RB_550 and RB_650, respectively), implying that almost all H 2 O is strong adsorbed on the carbon structure and further gasification of the sample requires higher reaction temperature.…”

Section: Results and Discussionmentioning

confidence: 99%

Effects of Alkaline Metals on the Reactivity of the Carbon Structure after Partial Supercritical Water Gasification of Coal

Wang

Zhang

et al. 2020

Energy Fuels

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Conversion of coal, biomass, and organic waste to combustible gases H 2 and CH 4 in supercritical water (SCW) is an economically and environmentally favored technology. Homogeneous alkaline catalysts are commonly added to achieve high conversion efficiency, as alkalis are believed to accelerate the gasification of aromatic structures, which is the bottleneck of the whole gasification process. Nevertheless, the mechanism of how alkali metals influence the reaction of aromatic structures is still not acknowledged clearly. In this work, different pretreatments of the high-alkali metal content Zhundong coal are taken as the object to study the effect of naturally present and artificial additive alkali metals on the microcrystalline carbon structure and their reactivity with H 2 O during the supercritical water gasification (SCWG) process. XRD analysis was applied to reveal that alkali metals inhibit the growth of graphite-like structures during SCWG. Subsequently, the separated smaller sized aromatic structures are indicated by calculating the Fukui function values of peripheral carbon atoms to exhibit higher reactivity with H 2 O and the free radicals in SCW. Finally, the existence of alkali metals is proven to promote the strong chemisorption of H 2 O on carbon structures, which is the premise of carbon abstraction of the aromatics, via thermogravimetric analysis. The influence of different reactors and SCW is also involved in the discussion. This work is prospective for optimal utilization of the homogeneous catalysts and developing innovative catalysts.

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“…Furthermore, due to the possible risks in release of radioactive medium under conditions with tube or vessel failures, the heat transfer of SCW is of much more concern for the safe operation of SCWRs than that of thermal power stations, and as a result, precise knowledge about the heat transfer characteristics of SCW is one of the major tasks for the design and operation of SCWRs [3,4]. Besides, heat transfer of SCW is of significance for other applications with SCW as the working fluid, such as SCW gasification system [5].…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Correlations for Supercritical Water in Vertically Upward Tubes

Li¹,

Kong²,

Lei³

et al. 2020

Advanced Supercritical Fluids Technologies

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Supercritical pressure water (SCW) has been widely used in many engineering fields and industries, such as fossil fuel-fired power plants, newly developed Gen-IV nuclear power plants and so forth. Heat transfer characteristics of SCW are of great importance for both design and safe operation of the related systems. Many heat transfer correlations have been developed in the history for predicting the heat transfer characteristics of SCW. However, the prediction accuracy of the existing correlations is less than satisfactory, especially in the cases with deteriorated heat transfer (DHT) because of the severe and quick variation in thermal physical properties of SCW in the vicinity of the fluids' pseudo critical point. It is very necessary to develop new correlations for the heat transfer of SCW to meet the engineering requirements for satisfactory prediction of the heat transfer behavior of SCW. In this chapter, experimental data on heat transfer of SCW are extensively collected from published literatures, and the performance of the existing heat transfer correlations for SCW are reviewed and quantitatively evaluated against the collected experimental data, and then a new heat transfer correlation for SCW with high prediction accuracy is proposed.

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Kinetics study for sodium transformation in supercritical water gasification of Zhundong coal

Cited by 44 publications

References 37 publications

Density Data of Two (H₂ + CO₂) Mixtures and a (H₂ + CO₂ + CH₄) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Density Data of Two (H₂ + CO₂) Mixtures and a (H₂ + CO₂ + CH₄) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Effects of Alkaline Metals on the Reactivity of the Carbon Structure after Partial Supercritical Water Gasification of Coal

Heat Transfer Correlations for Supercritical Water in Vertically Upward Tubes

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Kinetics study for sodium transformation in supercritical water gasification of Zhundong coal

Cited by 44 publications

References 37 publications

Density Data of Two (H2 + CO2) Mixtures and a (H2 + CO2 + CH4) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Density Data of Two (H2 + CO2) Mixtures and a (H2 + CO2 + CH4) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Effects of Alkaline Metals on the Reactivity of the Carbon Structure after Partial Supercritical Water Gasification of Coal

Heat Transfer Correlations for Supercritical Water in Vertically Upward Tubes

Contact Info

Product

Resources

About

Density Data of Two (H₂ + CO₂) Mixtures and a (H₂ + CO₂ + CH₄) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa

Density Data of Two (H₂ + CO₂) Mixtures and a (H₂ + CO₂ + CH₄) Mixture by a Modified Burnett Method at Temperature 673 K and Pressures up to 25 MPa