The behavior of catalysts in hydrogasification of sub-bituminous coal in pressured fluidized bed

Yan, Shuai; Bi, Jing; Qu, Xuanhui

doi:10.1016/j.apenergy.2017.08.189

Cited by 45 publications

(37 citation statements)

References 56 publications

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“…It could be seen form Table 4 that the I G /I All value had a certain degree of decrease and the I (D3+D4) /I G ratio was increased when the char catalyzed by catalysts, which illustrated that catalysts could inhibit the graphitization of char and create more active sites compared with the char without the catalyst. 16 The value of I (D3+D4) /I G for 1.0%Cu− 1.0%Ni−1.0%Ca was higher than others. The reason was that the synergistic effect of the metals made the interaction between the catalysts and the char more intense, which accelerated the breaking of more large aromatic rings to produce more active sites.…”

Section: Methodsmentioning

confidence: 72%

“…9,10, 14 Murakami, 15 however, found that the addition of Cacompounds not only retarded the agglomeration and sintering of the nickel catalyst but also effectively prevented the combination of nickel with sulfur to poisoning inactivation. The results reported by Yan 7,16 and Qu 12 supported this conclusion, which found that the addition of Ca also inhibited cobalt sintering. However, it was worth noting that the Ca-compounds were just promoters and they were almost inactive when added alone in the above research studies.…”

Section: Introductionmentioning

confidence: 68%

“…indicated the presence of Ca(OH) 2 (JCPDS 50-0008), which was due to the deliquescence of CaO during recovery. 16,28 The diffraction peaks at 36.64°, 52.76°, 65.93°, and 89.22°were attributed to the planes ( 200), ( 220), ( 222), and (420) of CaS (JCPDS 08-0464), respectively. The presence of CaS in the residue indicated that the reaction of calcium with organic sulfur in char reduced the probability of catalysts with sulfur, thereby reducing the toxicity of sulfur in char to the catalyst.…”

Section: Methodsmentioning

confidence: 99%

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Study of Cu–Ni–Ca Composite Catalysts in Catalytic Hydrogasification of Char

Sun

Zhang

et al. 2019

Energy Fuels

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The catalytic hydrogasification of char to synthetic natural gas was carried out in a pressurized fixed-bed reactor over Cu−Ni−Ca composite catalysts. The effect of the Cu−Ni ratio, Cu−Ni loading, reaction temperature on methane yield, and the methane formation rate was investigated. The characterization of these catalysts by X-ray diffraction showed that the Cu−Ni alloy was formed with a suitable Cu−Ni ratio during hydrogasification. Experiment results indicated that a suitable Cu− Ni ratio of 1:1 was favored for the formation of Cu−Ni alloy, which presented the highest catalytic activity. Methane yield and methane formation rate for 2.5%Cu−2.5%Ni−1.0%Ca reached 88.3% and 11.56 mL/(min•g char) at 800 °C and 2 MPa H 2 pressure in 450 min, respectively. The high catalytic performance of the Cu−Ni alloy was due to the isolation of Cu and Ni atoms from their adjacent atoms, resulting in more adsorption and dissociation of hydrogen molecules as well as the interaction between metal atoms and carbon. Moreover, a possible reaction mechanism for coal/char catalytic hydrogasification over Cu− Ni−Ca composite catalysts was proposed.

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Section: Methodsmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 68%

Section: Methodsmentioning

confidence: 99%

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Study of Cu–Ni–Ca Composite Catalysts in Catalytic Hydrogasification of Char

Sun

Zhang

et al. 2019

Energy Fuels

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“…Raman spectra have been widely used to investigate the aromaticity of coal and its derivatives 36,37 . Generally, two bands (G band and D band) can be identified in typical Raman spectra 38 . The overlapping area between G band and D band is further deconvoluted into three bands: V r (1380 cm −1 ), V l (1465 cm −1 ), and G r (1540 cm −1 ).…”

Section: Resultsmentioning

confidence: 99%

“…36,37 Generally, two bands (G band and D band) can be identified in typical Raman spectra. 38 The overlapping area between G band and D band is further deconvoluted into three bands: V r (1380 cm À1 ), V l (1465 cm À1 ), and G r (1540 cm À1 ). Based on previous reports, 30,39 Raman spectra from 800 to 1800 cm À1 are deconvoluted into 10 pure Gaussian bands, as shown in Figure 3.…”

Section: Macromolecular Structural Changesmentioning

confidence: 99%

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Han

2021

Intl J of Energy Research

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Sodium-rich coals are suitable raw materials for direct coal liquefaction (DCL).However, sodium species in coals, especially exchangeable ones, can significantly reduce oil yield. In this work, to increase oil yield in direct liquefaction of sodium-rich coals, a feasible method using organic solvents to pretreat sodium-rich coals is proposed. Initially, sodium-rich coal was thermally treated with tetralin or 1-methylnaphtalene. Then, raw coal and all the treated coals were liquefied under the same conditions to evaluate the effects of thermal treatment on structural changes of coal molecules and oil yield. The results show that surface areas of the treated coals increased to 7.86 m 2 /g at most, which was favorable for combination between hydrogen and coal molecules during the DCL process. More importantly, the content of hydrogen in the treated coals was 0.95 wt% higher than that of raw coal on average, suggesting that treated coals could be later liquefied at mild conditions. Raman spectra demonstrated that during thermal treatment with tetralin, small aromatic ring systems in raw coal were prehydrogenated and transformed into nonaromatic systems. The pre-hydrogenation of the coal matrix definitely contributes to the increase in oil yield. In view of sodium species distribution in the treated coals, it is proved that tetralin can promote the transformation of exchangeable sodium species into other chemical forms more easily than 1-methylnaphtalene, which implies that tetralin has more positive effects on the increase of oil yield. Compared with that of raw coal, oil yields in direct liquefaction of the samples treated by tetralin increase by 14.0 to 15.1 wt% (daf).

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A critical review on direct catalytic hydrogasification of coal into CH4: catalysis process configurations, evaluations, and prospects

Yan,

Feng,

Yuan

et al. 2024

Int J Coal Sci Technol

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Coal catalytic hydrogasification (CCHG) is a straightforward approach for producing CH4, which shows advantages over the mature coal-to-CH4 technologies from the perspectives of CH4 yield, thermal efficiency, and CO2 emission. The core of CCHG is to make carbon in coal convert into CH4 efficiently with a catalyst. In the past decades, intensive research has been devoted to catalytic hydrogasification of model carbon (pitch coke, activated carbon, coal char). However, the chemical process of CCHG is still not well understood because the coal structure is more complicated, and CCHG is a combination of coal catalytic hydropyrolysis and coal char catalytic hydrogasification. This review seeks to shed light on the catalytic process of raw coal during CCHG. The configuration of suitable catalysts, operating conditions, and feedstocks for tailoring CH4 formation were identified, and the underlying mechanisms were elucidated. Based on these results, the CCHG process was evaluated, emphasizing pollutant emissions, energy efficiency, and reactor design. Furthermore, the opportunities and strategic approaches for CCHG under the restraint of carbon neutrality were highlighted by considering the penetration of “green” H2, biomass, and CO2 into CCHG. Preliminary investigations from our laboratories demonstrated that the integrated CCHG and biomass/CO2 hydrogenation process could perform as an emerging pathway for boosting CH4 production by consuming fewer fossil fuels, fulfilling the context of green manufacturing. This work not only provides systematic knowledge of CCHG but also helps to guide the efficient hydrogenation of other carbonaceous resources such as biomass, CO2, and coal-derived wastes.

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The behavior of catalysts in hydrogasification of sub-bituminous coal in pressured fluidized bed

Cited by 45 publications

References 56 publications

Study of Cu–Ni–Ca Composite Catalysts in Catalytic Hydrogasification of Char

Study of Cu–Ni–Ca Composite Catalysts in Catalytic Hydrogasification of Char

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

A critical review on direct catalytic hydrogasification of coal into CH4: catalysis process configurations, evaluations, and prospects

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