Production of Clean Fuels by Catalytic Hydrotreating a Low Temperature Coal Tar Distillate in a Pilot-Scale Reactor

Liu, Dong; Chen, Wengang; Zhang, Xiangping; Meng, Qinghua; Zhou, Qiang; Ma, Baoqi; Niu, Menglong; Li, Wenhong

doi:10.1021/acs.energyfuels.7b01971

Cited by 31 publications

(19 citation statements)

References 49 publications

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“…1. The detailed hydrogenation process was consistent with previous studies published by our research group (Li et al 2017). According to the 1 H-NMR spectrum, hydrogen was divided into different types according to chemical shift and integrated (Lalvani et al 1991).…”

Section: Average Molecular Structure Model Of Coal Tar Asphaltenesupporting

confidence: 91%

Molecular Dynamics Analysis on Hydrogenation Process of Asphaltene Aggregate for Medium and Low Temperature Coal Tar

Han¹,

Wen-zhou²,

Liu³

et al. 2021

Preprint

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In this paper, the average molecular structure models of middle-low temperature coal tar (MLCT) asphaltene before and after hydrogenation were obtained by 1H-NMR characterization. Then the aggregation structure models of MLCT asphaltenes before and after hydrogenation was constructed in Materials Studio 8.0 software. The comparative analysis of structural characteristics between original and hydrogenated asphaltenes were carried out. The final configuration, molecular rotation radius and interaction energy of asphaltene aggerates before and after hydrogenation were analyzed by molecular dynamic simulation in different solvents.The conclusions are as follows: (1) The MLCT asphaltenes exist in the form of asphaltene aggregates before and after hydrogenation. After structural optimization, the original asphaltene molecules become 2-3 asphaltene molecules with approximately parallel, orderly arrangement and polycyclic aromatic hydrocarbons (PAH) stacking aggregate structure. The molecular accumulation number of its aggregate is less than that of petroleum asphaltene, and more complex nano-aggregates are formed by self-assembly among multiple aggregates. The accumulation number of asphaltene molecules after MLCT hydrogenation are less than that of original asphaltene. (2) The total interaction between MLCT primary asphaltene and hydrogenated asphaltene mainly comes from the intermolecular Van der Waals force. Compared with original asphaltene, the van der Waals energy and electrostatic energy of hydrogenated asphaltene are smaller and more affected by temperature. This shows that the intermolecular interaction of hydrogenated asphaltene is weak and the structure of the aggregate is unstable. (3) Aromatic compounds, strong basic compounds and strong polar compounds have good dissociation effect on MLCT asphaltenes and can effectively inhibit the aggregation and asphaltenes.

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Section: Average Molecular Structure Model Of Coal Tar Asphaltenesupporting

confidence: 91%

Molecular Dynamics Analysis on Hydrogenation Process of Asphaltene Aggregate for Medium and Low Temperature Coal Tar

Han¹,

Wen-zhou²,

Liu³

et al. 2021

Preprint

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“…Medium–low temperature coal tar pitch (MLP) is a type of large‐scale by‐product obtained during the production of semi‐coke and deep‐processing of low‐rank coal, respectively . MLP is usually used as the raw material for the production of liquefied oil, road asphalt, mesophase pitch, and other artificial carbon materials . The researchers believe that with the deep understanding of the physico‐chemical properties of MLP, it is a significantly important precursor to produce fine mosaic coke .…”

Section: Introductionmentioning

confidence: 99%

Thermal Conversion Behavior of Medium–Low–Temperature Coal Tar Pitch During Liquid–Phase Carbonization Process

Zhu

Zhao

et al. 2019

ChemistrySelect

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Medium–low temperature coal tar pitch (MLP) is a type of aromatic carbonaceous material obtained by the low temperature distillation of low rank coal, and is considered as a desirable raw material for the production of artificial carbon/graphite material. The thermal conversion behaviors of MLP during the liquid‐phase carbonization process were analyzed in detail in this study. Further, the changes of molecular structure and carbon microcrystalline structure of MLP and liquid‐phase carbonization products derived from it were quantitatively investigated by optical microscopy, fourier transform infrared spectroscopy, Raman spectroscopy, X‐ray diffraction, and curve‐fitting method. Results showed that both branched chain and the contents of C=O functional groups in the MLP played a key role in the reaction reactivity. Moreover, temperature of 450 °C was found to be a rapid changing temperature point on the enhancement of thermal conversion of MLP. The stacking height (Lc), parallel layers (N), average number of aromatic rings in each layer (n), ratio of ‘impurity’ structure (RI), ratio of amorphous carbon structure (RAC), ratio of graphite carbon structure (RGC), and ratio of defects graphite carbon structure (RDGC) exhibited a significant change with the improvement of liquid‐phase carbonization temperature.

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“…As Figure 5 displayed, the HDN effect of lump‐M on the K 1.24 model was better than that on the K 1 model at a LHSV range of 0.5–0.2 h −1 . The mechanism of NCs HDN usually consists of two key steps: hydrogenation of aromatic nitrogen heterocyclic and cleavage of the C–N bond 1,61 . Hydrogenation of aromatic nitrogen heterocyclic is the main control step for the removal of basic NCs, whereas the cleavage of the C–N bond is the main control step for the removal of nonbasic NCs 52 .…”

Section: Resultsmentioning

confidence: 99%

“…Another reason is that most of the NCs of lump‐M can be relatively easy to remove by hydrogenation at the initial stage, even at low pressure. However, some unconverted NCs still exist with complicated molecular structures which are extremely difficult to be converted in the whole HDN process considering the steric hindrance and hydrogen supply limitation 1,61 …”

Section: Resultsmentioning

confidence: 99%

“…With the drying up of processable crude oil, the utilization of new energy source, such as oil sand, oil shale, hydrogen energy, and coal‐derived oil for processing clean fuels, has gradually led to people's great attention in recent years 1–3 . The external dependence of crude oil in 2020 will reach about 70%, which causes serious imbalance between supply and demand for healthy economic development and energy security for China.…”

Section: Introductionmentioning

confidence: 99%

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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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Production of Clean Fuels by Catalytic Hydrotreating a Low Temperature Coal Tar Distillate in a Pilot-Scale Reactor

Cited by 31 publications

References 49 publications

Molecular Dynamics Analysis on Hydrogenation Process of Asphaltene Aggregate for Medium and Low Temperature Coal Tar

Molecular Dynamics Analysis on Hydrogenation Process of Asphaltene Aggregate for Medium and Low Temperature Coal Tar

Thermal Conversion Behavior of Medium–Low–Temperature Coal Tar Pitch During Liquid–Phase Carbonization Process

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

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