Application of microscopy to the investigation of brown coal pyrolysis

Shibaoka, Michio; Ohtsuka, Yasuo; Wornat, Mary J.; Thomas, C.G.; Bennett, Alan J.

doi:10.1016/0016-2361(95)00128-r

Cited by 42 publications

(28 citation statements)

References 18 publications

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“…Table 4 clarifies also that the HHV was slightly lower for the fuel with impregnated Ca ("Im" Ca). Corresponding to this is the product gas containing distinctively more H 2 and CO 2 and evidently less CO and hydrocarbons (CH 4 to C 3 H 6 ). The results, as will be analyzed hereafter, reflect rightly the excellent catalytic effects of the impregnated Ca.…”

Section: Resultsmentioning

confidence: 97%

“…[1][2][3][4][5][6][7] The dispersion of Ca onto coal particles can be implemented with either ion exchange 2,3 or impregnation/kneading. 2,4 Only through these technical means can the added Ca be bound to carboxylic sites of fuel molecular matrix to allow its pronounced catalytic effect on fuel gasification. 5,6 Obviously, either of these means implies somehow a complicated pretreatment of the fuel, 7 which surely increases the running cost.…”

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confidence: 99%

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Enhancing high water content biomass gasification with impregnated Ca in fuel drying

Murakami

Suda

et al. 2006

AIChE Journal

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In view of energy conversion efficiency, the gas production from high water content (Ͼ60 wt.%) biomass via gasification is necessarily conducted with fuel drying in advance. In regard to this kind of processes Process PhilosophyIt has long been recognized that dispersed calcium on coal greatly catalyzes coal pyrolysis and char gasification reactions. [1][2][3][4][5][6][7] The dispersion of Ca onto coal particles can be implemented with either ion exchange 2,3 or impregnation/kneading. 2,4 Only through these technical means can the added Ca be bound to carboxylic sites of fuel molecular matrix to allow its pronounced catalytic effect on fuel gasification. 5,6 Obviously, either of these means implies somehow a complicated pretreatment of the fuel, 7 which surely increases the running cost. Hence, more than 30 years after the quoted catalytic effect was observed, coal catalytic gasification has not yet seen any practical application.

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Section: Resultsmentioning

confidence: 97%

mentioning

confidence: 99%

Enhancing high water content biomass gasification with impregnated Ca in fuel drying

Murakami

Suda

et al. 2006

AIChE Journal

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“…It is known that loading of Na or Ca by ionexchange causes significant reduction of the yield of primary tar [44][45][46][47][48][49][50][51][52][53] that is the source of the soot-w and heavy tar as well the as soot-c and light tar. Thus, the result shown in Figure 4 was insufficient for demonstrating catalytic roles of the chars from the Na-form and Ca-form coals for indirect/direct steam reforming of the tar.…”

Section: Rapid Pyrolysis and In Situ Steam Gasification Of Single Coamentioning

confidence: 99%

Rapid Gasification of Nascent Char in Steam Atmosphere during the Pyrolysis of Na- and Ca-Ion-Exchanged Brown Coals in a Drop-Tube Reactor

et al. 2009

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Several recent studies on in situ steam gasification of coal suggest a possibility of extremely fast steam gasification of char from rapid pyrolysis of pulverized brown coal. The unprecedented rate of char steam gasification can be achieved by exposing nascent char, that is, after tar evolution (temperature range >600°C), but before devolatilization (<900°C), to steam in the presence of Na and/or Ca dispersed in/on the char. In this study, we conducted rapid pyrolysis experiments using ion-exchanged Loy Yang brown coal samples, that is, H-form coal with Na/Ca contents <0.001 wt %, Na-form coal with Na content = 2.8 wt % and Ca-form coal with Ca content=3.2 wt %. These samples were pyrolyzed in an atmospheric drop-tube reactor at a temperature of 900°C, inlet steam concentration of 50 vol. %, and a particle residence times of 2.8 s. The char yields from the pyrolysis of Na-form and Ca-form coals were as low as 12 and 33% on the respective coal carbon bases, and accounted for only 18 and 53% of the char yields from the full devolatilization of the respective coals at 900°C. In addition, the pyrolysis also consumed as much as 0.7-1.1 mol of H 2 O per mol of coal C. On the other hand, the nascent char from the H-form coal allowed carbon deposition from the nascent tar, resulting in a char yield as high as 115% of that from the full devolatilization. The chars from the Na-form and Ca-form coals also acted as catalysts for steam reforming of tar, which was evidenced by significant negative synergistic effects of blending of H-form coal with Na-form coal or Ca-form coal on the tar and soot yields.

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“…Though Shibaoka et al [32] found that there were no measurable differences in reflectance between demineralized sample and Na + -exchanged one. Our results show that extract yields of Na-0.1 and Na-0.5 both decrease obviously compared with that of De-H when THF or pyridine are used.…”

Section: Effect Of Exchangeable Na + On Solvent Extraction Of XLmentioning

confidence: 97%

Influences of exchangeable metallic species on solvent extraction of Xiaolongtan lignite and characterization of the separated portions

Bai

et al. 2015

Fuel Processing Technology

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Application of microscopy to the investigation of brown coal pyrolysis

Cited by 42 publications

References 18 publications

Enhancing high water content biomass gasification with impregnated Ca in fuel drying

Enhancing high water content biomass gasification with impregnated Ca in fuel drying

Rapid Gasification of Nascent Char in Steam Atmosphere during the Pyrolysis of Na- and Ca-Ion-Exchanged Brown Coals in a Drop-Tube Reactor

Influences of exchangeable metallic species on solvent extraction of Xiaolongtan lignite and characterization of the separated portions

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