Product compositions from catalytic hydroprocessing of low temperature coal tar distillate over three commercial catalysts

Chen, Wengang; Zheng, Hongtao; Niu, Menglong; Zhang, Shengjun; Li, Dong; Qiao, Jing; Li, Wenhong

doi:10.1007/s11144-016-1068-8

Cited by 12 publications

(15 citation statements)

References 54 publications

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“…At ref-40 °C, the sulfur content was reduced to approximately 43 μg/g and, at ref+20 °C, to 3 μg/g; meanwhile, the nitrogen level can be reduced only to 216 μg/g at ref-40 °C, and at ref+20 °C to 6 μg/g, which suggested that, compared to nitrogen compounds in feedstock, most of the Scontaining species were more reactive which can be much more easily removed from coal tar during the hydrogenation process, which is in accordance to literature. 15,19,34 Most of nitrogen was found to occur as aromatic compounds (such as pyridines, quinolines, pyrroles, indoles, and carbazoles, and so on), due to the strong C−N bond in aromatic systems, 42−45 which are resistant to HDN. Meanwhile, it is generally accepted that HDN of aromatic N-containing compounds occurs via a twostep process involving complete hydrogenation of the aromatic rings followed by irreversible C−N bond scission (hydrogenolysis).…”

Section: Resultsmentioning

confidence: 99%

“…Catalytic hydrotreating may be considered as the most convenient way to upgrade a coal tar distillate to produce clean liquid fuels; through hydrotreating processes, heteroatomic compounds and aromatic content can be considerably reduced simultaneously . Researchers have conducted extensive studies concerning the hydrotreating processes during coal tar upgrading. ,− Meanwhile, due to the high viscosity and complex structure, researchers have focused on the study of model compounds such as phenanthrene, anthracene, naphthalenes, − phenols, − and so on, rather than on a real fraction. Though abundant research on catalytic hydrotreating coal tar has been carried out, the studies still have some shortcomings: (i) Most of the research has focused on one or two kinds of catalysts, not involving the influence of catalyst grading combination technology. ,, (ii) Studies about real reaction behavior of a low temperature coal tar (LTCT) distillate during industrial operation have not been reported.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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China is one of the largest coal producers in the world and abundant coal tar is produced from coal gasification and carbonization every year. Thus, catalytic hydrotreating coal tar for the production of clean fuel has received substantial attention. In this work, clean liquid fuel was obtained from the catalytic hydrogenation of a low temperature coal tar (LTCT) distillate in a four-stage fixed bed reactor with various catalyst combinations on the pilot scale. Effects of dominant hydrotreating parameters, reaction temperature (290−390 °C), H 2 pressure (8−15 MPa), and liquid hourly space velocity (0.2−0.6 h −1 ), on hydrotreating activity, the intermediate and final products, and chemical components of the hydrogenated oils were evaluated. Meanwhile, a possible reaction scheme for the conversion of alkyl-naphthalenes (AN) and phenols in feedstock was probed. The results showed that the four-stage reacting system was capable of removing sulfur and nitrogen to less than 10 μg/g. Furthermore, after hydrotreating, AN were transformed into decalins, tetralin, and indenes, and alkyl-cycloalkanes (CA) were the main and final products of phenolic compound hydrodeoxygenation (HDO). In addition, coke formation of the spent catalysts was also studied by thermogravimetric techniques, which suggested that the coke deposits are mainly concentrated in the second and third stages of the reactor. The results of this work show that high-quality clean fuels can be obtained through the multistage hydrotreating process with a catalyst gradation technology, which may bridge the gap between fundamental research and industrial production and offer a route for deep processing of LTCT.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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“…In order to facilitate analysis, the components were grouped into alkanes, phenols, alkyl-naphthalene (AN), alkylbenzene (AB), indenes, fluorenes, phenanthrenes, anthracenes, biphenyls, alkenes, and O-containing compounds (mainly including ketones, ethers, aldehydes, alkanoates, carboxylic acids, etc., except phenols), and a detailed classification method was shown in our previous studies. 20,54 As shown in Figure 1, alkanes, phenols, and AN were the three most abundant compounds in the feedstock, which accounting for 36.7%, 25.38%, and 20.8%, respectively. Aromatics made up more than 30% of the feedstock and most of them were polycyclic aromatic hydrocarbons.…”

Section: Methodsmentioning

confidence: 99%

Hydroprocessing of Low-Temperature Coal Tar for the Production of Clean Fuel over Fluorinated NiW/Al₂O₃–SiO₂ Catalyst

Chen

Gao

et al. 2017

Energy Fuels

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Hydroprocessing of low-temperature coal tar (LTCT) for the production of clean fuel was investigated over fluorinated NiW/Al2O3–SiO2 catalyst in a fixed bed reactor. A series of NiW/Al2O3–SiO2 catalysts with different F-loading were prepared by incipient wetness coimpregnation and characterized by various techniques such as nitrogen adsorption, FT-IR, XRD, SEM TPD-NH3, and XPS. The effects on the yield, properties of liquid products, and gas components from using fluorinated NiW/Al2O3–SiO2 catalysts were discussed. In addition, coke formation was also evaluated by TG-DTG. The result showed that the introduction of F influenced both acidity and active phase while have little effect on crystalline structure of NiW/Al2O3–SiO2 catalysts. Lower F-loading in the NiW/Al2O3–SiO2 catalysts not only improved catalytic performance but also was helpful to improve some of the physicochemical properties of liquid product including dynamic viscosity, density, distillation range and hydrocarbon content, and so on. The optimal F concentration to NiW/Al2O3–SiO2 is 1.0 wt %, at which the highest naphtha and diesel yield was obtained due to its appropriate acid distribution and more active phase. Meanwhile, liquid product produced displayed the lowest N content (78.6 ug/g) and density (0.8507 g/mL). Furthermore, compared with feedstock, phenols almost disappeared and phenyl cycloalkanes (PCA) and cycloalkanes (CA) are rich in hydrogenated product.

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“…Co–Mo and Ni–Mo catalysts exhibited high hydrogenolysis capability for S-, O-, and N-containing heteroatoms. For <350 °C distillates, the sulfur compound is the most liable heteroatom species in the hydroprocessing and could be almost completely removed, ,, while nitrogen and oxygen contents can be reduced to less than 50 ppm. , A certain amount of nitrogen and oxygen was remained after the hydrogenation of a raw LTCT. , The Ni–W catalyst showed a high hydrocracking activity and intermediate carbon number (C 9 –C 16 ) selectivity . These works reported the heteroatom content in the LTCT before and after the hydrogenation process and mainly focused on the removal ratio of heteroatoms.…”

Section: Introductionmentioning

confidence: 99%

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

Chen

Wang

et al. 2018

Energy Fuels

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A low-temperature coal tar was subject to a three-stage catalytic hydrotreating reactor. The raw coal tar and its hydrotreating products from each reactor section were characterized by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The removal efficiencies of sulfur, nitrogen, and oxygen were 99.4%, 88.4%, and 78.1%, respectively. The molecular transformation routes of each heteroatomic species are different. Sulfur species were removed from low double bond equivalence (DBE) values to higher values through the whole hydrotreating process. Furanic compounds and basic nitrogen compounds carried out the saturation of aromatic rings before the hydrogenation of low DBE species. Neutral nitrogen compounds were resistant in the processing and cannot be removed completely in the end of the hydroprocessing. The phenolic compounds were the most resistant to hydrotreating during the whole process. The transformation capabilities of heteroatom compounds in the processing were as follows: phenolic compounds > neutral nitrogen compounds > furanic compounds > basic nitrogen compounds > sulfur compounds.

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Product compositions from catalytic hydroprocessing of low temperature coal tar distillate over three commercial catalysts

Cited by 12 publications

References 54 publications

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

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

Hydroprocessing of Low-Temperature Coal Tar for the Production of Clean Fuel over Fluorinated NiW/Al₂O₃–SiO₂ Catalyst

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

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Product compositions from catalytic hydroprocessing of low temperature coal tar distillate over three commercial catalysts

Cited by 12 publications

References 54 publications

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

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

Hydroprocessing of Low-Temperature Coal Tar for the Production of Clean Fuel over Fluorinated NiW/Al2O3–SiO2 Catalyst

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

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Hydroprocessing of Low-Temperature Coal Tar for the Production of Clean Fuel over Fluorinated NiW/Al₂O₃–SiO₂ Catalyst