Online-CPD-Coupled Large-Eddy Simulation of Pulverized-Coal Pyrolysis in a Hot Turbulent Nitrogen Jet

Wan, Kaidi; Xia, Jun; Wang, Zhihua; Wrobel, L.C.; Cen, Kefa

doi:10.1080/00102202.2016.1193498

Cited by 19 publications

(25 citation statements)

References 59 publications

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“…Coal, as an energy source, supports approximately 40% of the worldwide electricity [1]. Due to its broad availability and the flexibility of coal combustion systems, the utilization of coal is expected to continue in the near and medium future [2,3]. It was known that the presence of sodium in coal can lead to rapid ash deposition on heat transfer surfaces of coal-fired boilers [4].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of sodium release from Zhundong coal via the addition of mineral additives: A combination of online multi-point LIBS and offline experimental measurements

Liu

Wang

et al. 2018

Fuel

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The retention performance of 5 different sorbent additives, including 2 pure additives, i.e., silica and alumina, and 3 typical natural mineral additives, i.e., kaolin, mica and pyrophyllite, on the release of sodium during the combustion of Zhundong coal is investigated via a combination of online multipoint Laser-Induced Breakdown Spectroscopy (LIBS) technique and offline measurements including inductively coupled plasma atomic emission spectrometer (ICP-AES), X-ray diffraction, and ash fusion temperatures (AFTs). The online and offline measurement results for the sodium release of Zhundong coal/additives mixtures are compared and verified with each other. Ternary phase diagram simulations are performed to further substantiate the impact of different additives on liquidus temperatures of Zhundong coal ash. All the five sorbent additives show a significant sodium retention effect, while alumina and kaolin are better additives considering the effects on AFTs.

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Section: Introductionmentioning

confidence: 99%

Inhibition of sodium release from Zhundong coal via the addition of mineral additives: A combination of online multi-point LIBS and offline experimental measurements

Liu

Wang

et al. 2018

Fuel

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“…Coal, as an important source of primary energy, supports approximately 40% of the worldwide electricity [1,2]. Considering its broad availability and the overall flexibility of coal combustion systems, coal is expected to continually play an important role in the near future [3,4]. In practice, the presence of alkali metals, especially sodium (Na), in coals leads to severe ash-related issues, such as fouling, slagging and corrosion [5].…”

Section: Introductionmentioning

confidence: 99%

In Situ Measurements of the Release Characteristics and Catalytic Effects of Different Chemical Forms of Sodium during Combustion of Zhundong Coal

et al. 2018

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This work studies the temporal release characteristics of different chemical forms of sodium during the combustion of Zhundong coal and the catalytic effects of sodium on the combustion process via target-sodium removal and enrichment approaches. The target-sodium removal approach extracts specific forms of sodium from the raw coal via a chemical method to produce coal samples with designated characteristics. In the target-sodium enrichment approach, three kinds of H2O-soluble sodium compounds, including NaCl, NaOH and Na2SO4, are manually added into the raw coal. The experimental measurement is conducted using a multi-point Laser-Induced Breakdown Spectroscopy (LIBS) system. The system quantitatively measures the temporal release flux of sodium during the combustion process, and performs the in-situ measurement of surface temperature and diameter of a burning coal pellet. It is found that H2O-soluble sodium is the major chemical form of sodium released during the combustion and exhibits the highest volatility. All the three forms of enriched H2O-soluble sodium compounds show a catalytic effect on the coal combustion (burnout time decreased by more than 5.7%) and the catalytic activity of NaOH is found to be the strongest (burnout time decreased by 36.8%).

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“…The governing equations for the gas mixture are solved with a low-Mach number in-house code [27][28][29][30][31]. The conservation equations for mass, momentum, species and temperature of the gas phase are those of [31], here without the source terms due to coal particles.…”

Section: Turbulent Flame Configuration and Numericsmentioning

confidence: 99%

Machine learning for detailed chemistry reduction in DNS of a syngas turbulent oxy-flame with side-wall effects

Wan

Barnaud

Domingo

2021

Proceedings of the Combustion Institute

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A novel chemistry reduction strategy based on convolutional neural networks (CNNs) is developed and applied to direct numerical simulation (DNS) of a turbulent non-premixed flame interacting with a cooled wall. The fuel syngas mixture is burning in pure oxygen. The training and the subsequent application of the CNN rely on the processing of two-dimensional (2D) images built from species mass fractions and temperature (CNN input), to predict the corresponding chemical sources at the center of the image (CNN output). This image-type treatment of chemistry is found to efficiently capture intermediate radicals species highly sensitive to the local flame topology. To reduce the CPU cost, a simplified 2D DNS database with detailed chemistry serves as reference and is used for training and testing the neural network. Comparisons are also made a posteriori against the same 2D DNS with a reduced chemical scheme specialized for syngas. Then, three-dimensional (3D) DNS are conducted either with CNN or the reduced chemistry for more a posteriori tests. The CNN reduced chemistry outperforms the reduced Arrhenius based mechanism in the prediction of radical species, such as monoatomic hydrogen, and also in terms of CPU cost.

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Online-CPD-Coupled Large-Eddy Simulation of Pulverized-Coal Pyrolysis in a Hot Turbulent Nitrogen Jet

Cited by 19 publications

References 59 publications

Inhibition of sodium release from Zhundong coal via the addition of mineral additives: A combination of online multi-point LIBS and offline experimental measurements

Inhibition of sodium release from Zhundong coal via the addition of mineral additives: A combination of online multi-point LIBS and offline experimental measurements

In Situ Measurements of the Release Characteristics and Catalytic Effects of Different Chemical Forms of Sodium during Combustion of Zhundong Coal

Machine learning for detailed chemistry reduction in DNS of a syngas turbulent oxy-flame with side-wall effects

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