Composition and Transformation of Sulfur-, Oxygen-, and Nitrogen-Containing Compounds in the Hydrotreating Process of a Low-Temperature Coal Tar

Ni, Hongxing; Chen, Xu; Wang, Rui; Guo, Xing‐Min; Long, Yinhua; Ma, Chao; Yan, Lulu; Liu, Xuxia; Shi, Quan

doi:10.1021/acs.energyfuels.7b03659

Cited by 39 publications

(16 citation statements)

References 31 publications

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“…Coal is not only the most important energy source, but also an important raw material for modern metallurgical and chemical industries [1]. Understanding the molecular structure of coal is the basis of coal development and utilization and coal chemistry research [2], and is also the main research direction of coal chemists today [3][4][5]. The complexity and heterogeneity of coal make it more difficult to study its structure [6,7].…”

Section: Introductionmentioning

confidence: 99%

Fine Characterization of the Macromolecular Structure of Huainan Coal Using XRD, FTIR, 13C-CP/MAS NMR, SEM, and AFM Techniques

Zhang

et al. 2020

Molecules

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Research on the composition and structure of coal is the most important and complex basic research in the coal chemistry field. Various methods have been used to study the structure of coal from different perspectives. However, due to the complexity of coal and the limitations of research methods, research on the macromolecular structure of coal still lacks systematicness. Huainan coalfield is located in eastern China and is the largest coal production and processing base in the region. In this study, conventional proximate analysis and ultimate analysis, as well as advanced instrumental analysis methods, such as Fourier transform infrared spectroscopy (FITR), X-ray diffraction (XRD), 13C-CP/MAS NMR, and other methods (SEM and AFM), were used to analyze the molecular structure of Huainan coal (HNC) and the distribution characteristics of oxygen in different oxygen-containing functional groups (OCFGs) in an in-depth manner. On the basis of SEM observation, it could be concluded that the high-resolution morphology of HNC’s surface contains pores and fractures of different sizes. The loose arrangement pattern of HNC’s molecular structure could be seen from 3D AFM images. The XRD patterns show that the condensation degree of HNC’s aromatic ring is low, and the orientation degree of carbon network lamellae is poor. The calculated ratio of the diameter of aromatic ring lamellae to their stacking height (La/Lc = 1.05) and the effective stacking number of aromatic nuclei (Nave = 7.3) show that the molecular space structure of HNC is a cube formed of seven stacked aromatic lamellae. The FTIR spectra fitting results reveal that the aliphatic chains in HNC’s molecular structure are mainly methyne and methylene. Oxygen is mainly –O–, followed by –C=O, and contains a small amount of –OH, the ratio of which is about 8:1:2. The molar fraction of binding elements has the approximate molecular structure C100H76O9N of organic matter in HNC. The results of the 13C NMR experiments show that the form of aromatic carbon atoms in HNC’s structure (the average structural size Xb of aromatic nucleus = 0.16) is mainly naphthalene with a condensation degree of 2, and the rest are aromatic rings composed of benzene rings and heteroatoms. In addition, HNC is relatively rich in ≡CH and –CH2– structures.

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Section: Introductionmentioning

confidence: 99%

Fine Characterization of the Macromolecular Structure of Huainan Coal Using XRD, FTIR, 13C-CP/MAS NMR, SEM, and AFM Techniques

Zhang

et al. 2020

Molecules

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“…Meanwhile, hydrocracking increases the H/ C ratio and removes heteroatoms S, N, and O and metals from the bio-oil. Ni et al64 examined the effect of S-, O-, and Ncontaining compounds in the hydrotreating process of a lowtemperature coal tar and found the furanic compounds and nitrogen compounds in coal tar were mainly converted to saturation of aromatic rings. Corma et al35 achieved complete conversion of the pure sunflower oil with a 71% yield of C 15 −C 18 alkanes over sulfided Ni−Mo/Al 2 O 3 at 350 °C via hydroprocessing 65.…”

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confidence: 99%

Catalytic Conversion of Coal and Biomass Volatiles: A Review

et al. 2020

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This paper presents a review of recent research on direct upgrading of coal/biomass volatiles into aromatics by catalytic pyrolysis and syngas by gasification with catalytic steam reforming. Coal/biomass valorization is considered an important part to fill up the depletion of modern fossil fuel resources. The catalytic pyrolysis process is a potential approach to improve coal tar/bio-oil quality by minimizing its undesirable properties (high viscosity, corrosivity, instability, etc.) and producing renewable fuels and high-value chemicals, such as aromatics (benzene, toluene, ethylbenzene, xylenes, etc.). Gasification reforming as a promising process for renewable energy utilization can produce H2-rich syngas. The produced syngas can be further synthesized to fuel and chemicals via Fischer–Tropsch synthesis. Thus, this study provides a comprehensive review of the research and development of conversion of coal and biomass volatiles in terms of technological types and catalysts. Aspects related to upgrading technology, the reactor type of catalytic pyrolysis and gasification, and the reaction mechanisms to specific products during the catalytic process are also discussed comprehensively. In particular, catalytic upgrading by fast pyrolysis involves a series of reactions, including deoxygenation, cracking, hydrocarbon pool mechanism, aromatization, and condensation, as well as desulfurization and denitrification in the gasification process. Some key points that are to be addressed for the established process of coal and biomass volatile upgrading may include finding multifunctional catalysts and reactor development for improving the efficiency. Expanding and enhancing knowledge about catalyst utilization and fundamental reaction mechanisms in the thermochemical catalytic conversion technologies of coal and biomass will play an important role in the generation of chemicals and carbon-neutral fuels.

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“…The nitrogen element mainly combines with aliphatic amines, aromatic amines, complex basic heterocyclic NCs (pyridines, quinolines), nonbasic NCs (pyrroles, indenes, carbazoles), and some heterocyclic NCs in MLCT 42–44 . Among them, aliphatic amines and aromatic amines are easier to remove under hydrogenation conditions, while the basic heterocyclic NCs and non‐basic NCs, especially a number of polycyclic nonbasic and polycyclic NCs, are more difficult to remove.…”

Section: Resultsmentioning

confidence: 99%

“…NCs exist in various forms in MLCT, especially rich in heavy fractions, which make their removal difficult in the HDN process 42–44 . In order to obtain the clear reaction laws of HDN, NCs in MLCT were divided into three lumps consisting of high‐reactivity NCs lump (lump‐H), middle‐reactivity NCs lump (lump‐M), and low‐reactivity NCs lump (lump‐L) according to the hydrogenation reactivity 45–46 .…”

Section: Establishment and Solution Of Kinetic Modelmentioning

confidence: 99%

Lumped kinetic simulation of hydrodenitrogenation for full‐range middle‐low temperature coal tar

Dan

et al. 2021

Int J of Chemical Kinetics

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With the increasingly prominent environmental problems and depletion of light petrochemical resources, the clean utilization of heavy oil has become the research focal area. The hydrodenitrogenation (HDN) experiments and kinetics of full‐range middle‐low temperature coal tar (MLCT) was studied on a fixed‐bed reactor with a Ni‐Mo/γ‐Al2O3 catalyst. Two kinds of three‐lumped kinetic models (K1 and K1.24) based on different reaction orders and high‐middle‐low reactivities were established and fitted by a simulated annealing algorithm for coal tar HDN reactions. The results presented good correspondence with experimental data following an average relative error of less than 0.3%. The effect of temperature, pressure, and liquid hourly space velocity (LHSV) on HDN of different reactivity nitrogen compounds (NCs) of MLCT was studied using the lumped kinetic models. Also, the difference between K1 and K1.24 models on the embodiment ability for HDN laws was also discussed from multiple perspectives. It has been observed that the HDN reactions of low and middle reactivity NCs are more influenced by LHSV; high temperature and pressure are more critical for the removal of low reactivity NCs, and low‐temperature or ‐pressure zone have larger effects on coal tar HDN reactions, especially at high LHSV; temperature has much more influence than pressure on the HDN effect, particularly towards the low reactivity NCs. The results of HDN laws for high reactivity NCs are concordant with K1 and K1.24 models. The K1.24 model is a bit more reasonable to reveal the HDN law of middle to low reactivity NCs.

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Composition and Transformation of Sulfur-, Oxygen-, and Nitrogen-Containing Compounds in the Hydrotreating Process of a Low-Temperature Coal Tar

Cited by 39 publications

References 31 publications

Fine Characterization of the Macromolecular Structure of Huainan Coal Using XRD, FTIR, 13C-CP/MAS NMR, SEM, and AFM Techniques

Fine Characterization of the Macromolecular Structure of Huainan Coal Using XRD, FTIR, 13C-CP/MAS NMR, SEM, and AFM Techniques

Catalytic Conversion of Coal and Biomass Volatiles: A Review

Lumped kinetic simulation of hydrodenitrogenation for full‐range middle‐low temperature coal tar

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