Catalytic Cracking of Pyrolytic Vapors of Low-Rank Coal over Limonite Ore

He, Lu; Li, Songgeng; Lin, Weigang

doi:10.1021/acs.energyfuels.6b01182

Cited by 29 publications

(5 citation statements)

References 30 publications

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“…The SiO 2 /Al 2 O 3 molar ratio of 25 was confirmed with excellent ability for the volatiles-to-aromatics reaction because of its large specific surface and adequate acid sites . However, some macromolecules in pyrolysis volatiles, which account for 60–70% in tar, could not enter the channels of microporous H5 and would polymerize on the surfaces to block the channels. , The treatment with alkali solution is considered as an efficient method to enlarge the pores. In previous work, a series of hierarchical H5 was prepared by desilication and dealumination with different alkali and acid solutions, respectively. , Appropriate basicity could create new mesopores and decrease acid amounts .…”

Section: Introductionmentioning

confidence: 92%

“…8 However, some macromolecules in pyrolysis volatiles, which account for 60−70% in tar, could not enter the channels of microporous H5 and would polymerize on the surfaces to block the channels. 9,10 The treatment with alkali solution is considered as an efficient method to enlarge the pores. In previous work, a series of hierarchical H5 was prepared by desilication and dealumination with different alkali and acid solutions, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Light Aromatic Yield from Lignite Pyrolysis by Remedying the Acid Sites of Different Hierarchical HZSM-5

et al. 2019

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A series of HZSM-5 treated by NaOH followed by supporting sulfated zirconia (AT x SZ/H5) was prepared and used for catalytic reforming of lignite pyrolysis volatiles. AT x SZ/H5 was found to be a potentially promising catalyst for removing oxygen from vapors to produce aromatics and olefin. The highest yields of benzene, toluene, ethylbenzene, xylene, and naphthalene (BTEXN) were obtained over 3% SZ supported on HZSM-5 treated by 0.2 mol/L NaOH (AT 0.2 SZ/H5) as a result of the abundant hierarchical pores and suitable acidic density. Moreover, raising the NaOH concentration for zeolites caused the enhancement of olefin yields. The polycyclic aromatic hydrocarbons chemisorbed over zeolite can be activated by the hydrogen transfer reaction to increase the selectivity of C 2+ . Comprehensive catalyst characterization using temperatureprogrammed desorption with ammonia, N 2 physisorption, X-ray diffraction, and inductively coupled plasma optical emission spectrometry enabled establishing structure−performance relationships with a major role of the zeolite structure, density of strong acid sites, and mesoporosity. AT x SZ/H5 exhibited a suitable physicochemical property, including the addition of strong acid species and acidity, suitable pore structure, and specific surface area. Additionally, in comparison to H5, the yields of BTEXN over AT 0.2 SZ/H5 increased from 12.8 to 18.9 mg/g, but excessive alkali over H5 had a negative effect on the BTEXN yield because of the structure collapse.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Enhanced Light Aromatic Yield from Lignite Pyrolysis by Remedying the Acid Sites of Different Hierarchical HZSM-5

et al. 2019

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“…For example, when the amount of SLA added is increased from 0% to 10%, the MAHs content in the tar increases from 21.19% to 31.04%, the AHs content increases from 2.31% to 10.74%, the PAHs content decreases from 11.85% to 7.23%, the Phenols content decreases from 31.96% to 26.87%, and the NOCs decreases from 33.19% to 24.12%. The reason is that Fe 2 O 3 promotes the breakage of C-O and C-C bonds, which can convert NOCs as well as PAHs into lighter components and promote the production of AHs and MAHs 34,35 while generating CO, H 2 , and CH 4 gases. In addition, Fe 2 O 3 promotes the occurrence of dephenolization of hydroxyl groups, leading to a decrease in the content of Phenols.…”

Section: Analysis Of the Synergistic Mechanismmentioning

confidence: 99%

Preparation of calcium sulfide by sludge‐assisted rice husk reduction of phosphogypsum

Wang

Tian

2023

Asia-Pacific J Chem Eng

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Reduction of phosphogypsum (PG) to calcium sulfide (CaS) using thermochemical methods solve the environmental problems caused by PG. However, the commonly used reducing agents are coal and CO. The use of the above‐mentioned reducing agents is not economically efficient. In this paper, rice husk (RH) is used as a reducing agent and sludge (SL) as an additive to reduce PG. The effect of the two on PG decomposition and the mechanism of the synergistic effect are also investigated in combination with kinetic calculations. It is found that decomposition rate of CaSO4 in PG is 99.99% and yield of CaS is 98.38% when 40% RH + 20% SL is used as the reducing agent at 900°C for 30 min. The combined use of RH + SL is superior to RH alone in reducing the initial decomposition temperature and Ea. The mechanism functions of both reduced PG are G(α) = −ln(1 − α). There is a synergistic mechanism between RH and SL. The Fe2O3 in SL increases the cleavage of nitrogen oxide‐containing compounds and PAHs in tar to monocyclic aromatic and aliphatic hydrocarbons while producing more CO, H2, and CH4. Meanwhile, SL ash can promote the reaction process of carbon with CaSO4, thus increasing the decomposition rate of PG.

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“…Light aromatics, such as benzene, toluene, xylene, and naphthalene (BTXN), are important industrial chemicals, widely used as fuel additives, solvents, and the feedstock for production of pesticides, plastic products, and synthetic fibers. 55 The nature and quantity of BTXN are depicted in Figure 10 expressed as integrated intensity per milligram of coal. Compared with SD, the amount of benzene, toluene, xylene, and naphthalene released from SD-DE increased by 9.40%, 6.03%, 2.14%, and 5.91%, respectively.…”

Section: Chemical Composition Of Pyrolysismentioning

confidence: 99%

Study on the Volatiles and Kinetic of in-Situ Catalytic Pyrolysis of Swelling Low-Rank Coal

Min

Zheng

et al. 2017

Energy Fuels

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A new method combined solvent swelling with an in-situ catalytic effect of metal ions was developed and introduced in coal pyrolysis to increase the coal conversion and the tar yield as well as to improve the quality of the tar products. Low-rank coal of Shendong coal from China was used to investigate the effect of demineralization, swelling, and in-situ catalysis on pyrolysis reactivity and kinetic characteristics, yield distribution of products, and the tar composition. The experiments were performed using a thermogravimetric analyzer/Fourier transform infrared spectrometer (TG-FTIR), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and a fixed-bed reactor to examine the pyrolysis behavior of raw coal, demineralized coal, methanol swelling demineralized coal, and methanol swelling with metal ions (Ca2+, Cu2+, and Co2+) in-situ-impregnated coal, respectively. The results showed that coal conversion could be promoted by pretreatment of solvent swelling and in-situ-impregnated Cu2+ and Co2+ ions, respectively. The gas evolution results of FTIR indicated that the in-situ loading of Cu2+ and Co2+ ions had a catalytic effect on the evolution of CO2, CH4, and aromatics of the swollen coal. The tar yield of demineralized coal was improved by the methanol-swelling pretreatment. With the in-situ loading of Cu2+ and Co2+ ions, the tar yield of swelling coal further increased by 16.80% and 28.75%. The composition of tar analyzed by Py-GC/MS indicated that methanol swelling increased the relative content of the acidic compounds and also had a positive effect on the yields of PCX (phenol, cresol, xylenol). The in-situ loading of metal ions increased the relative content of the aromatic compounds but had a different effect on the formation of BTXN (benzene, toluene, xylene, and naphthalene). The Cu2+ and Co2+ ions had a catalytic effect on phenols decomposition during coal pyrolysis, resulting in a decrease of the relative content of the acidic compounds dramatically. The kinetic results showed that the in-situ impregnation of Ca2+, Cu2+, and Co2+ ions into the swollen coal could result in a decrease of the activation energy and pre-exponential factor at the corresponding temperature range of the first and the second prolysis stage. In addition, a possible mechanism on in-situ catalytic pyrolysis of swelling coal was discussed and proposed based on the evolution and composition of the evolved species investigated during pyrolysis. The impregnation of the metal ions may catalyze the primary reactions and secondary reactions during coal pyrolysis.

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Catalytic Cracking of Pyrolytic Vapors of Low-Rank Coal over Limonite Ore

Cited by 29 publications

References 30 publications

Enhanced Light Aromatic Yield from Lignite Pyrolysis by Remedying the Acid Sites of Different Hierarchical HZSM-5

Enhanced Light Aromatic Yield from Lignite Pyrolysis by Remedying the Acid Sites of Different Hierarchical HZSM-5

Preparation of calcium sulfide by sludge‐assisted rice husk reduction of phosphogypsum

Study on the Volatiles and Kinetic of in-Situ Catalytic Pyrolysis of Swelling Low-Rank Coal

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