Characteristics of oil shale pyrolysis in a two-stage fluidized bed

Tian, Yong; Li, Mengya; Lai, Dengguo; Chen, Zhaohui; Gao, Shiqiu; Xu, Guangwen

doi:10.1016/j.cjche.2017.02.008

Cited by 19 publications

(6 citation statements)

References 22 publications

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“…The decreasing amount of shale oil is approximately equal to the sum of the increasing amount of noncondensable gas and water, which implies that higher temperature might promote more shale oil to further decompose into noncondensable gas and water. In addition, the variation in shale oil yield with temperature indicates that there exists a temperature near 520 °C for shale oil yield to be maximized, which is similar to the experimental results for other oil shales. − One explanation of this maximum is that when the retorting temperature is below this temperature, the kerogen in oil shale could not be sufficiently pyrolyzed, and when the retorting temperature is higher than this temperature, the secondary cracking reaction of shale oil would be enhanced, resulting in a decrease in shale oil yield and a significant increase in noncondensable gas yield. As well as this gas from the secondary cracking of the products of retorting, some noncondensable gases will also be generated during the primary pyrolysis of the kerogen.…”

Section: Results and Discussionsupporting

confidence: 74%

Studies of the Bubbling Fluidized Bed Retorting of Dachengzi Oil Shale: 1. Effect of Retorting Temperature

et al. 2021

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Fluidized bed retorting of oil shale is a potential technology with high shale oil yield. However, there are few studies on the composition distribution of the products of this technology. In this work, Dachengzi oil shale from Huadian city of China was retorted in a bubbling fluidized bed reactor, focusing on the effect of retorting temperature on the yield and composition distribution of products. With increasing retorting temperature, shale oil yield increased up to 522 °C and then decreased, and noncondensable gas always kept slow growth, while shale char decreased significantly. The H/C atomic ratio of shale oil decreased with increasing temperature, which was attributed to the strengthened dehydrocyclization and aromatization reactions of shale oil. Higher temperatures promoted more oxygen-containing functional groups releasing in forms of CO 2 and CO, decreasing the O/C atomic ratio of shale oil. At the same time, higher retorting temperatures could also enhance cracking reactions and thus reduce heavy fractions of shale oil. With the increase of retorting temperature, the content of aliphatics decreased up to 562 °C and then increased, while the content of aromatics was always increasing. The yields of inorganic gases and some hydrocarbon gases, as well as the total alkenes/alkanes ratio increased because of the strengthened secondary cracking reactions at higher temperatures.

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Section: Results and Discussionsupporting

confidence: 74%

Studies of the Bubbling Fluidized Bed Retorting of Dachengzi Oil Shale: 1. Effect of Retorting Temperature

et al. 2021

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“…When the temperature increases, the shale oil will undergo a secondary pyrolysis reaction in a closed reactor. The main types of secondary reactions are condensation and aromatization of aliphatic hydrocarbons. , At 360 °C, the contents of olefins and aromatic products in shale oil are 8 and 12%, respectively. When the temperature is increased to 400 °C, the contents of olefins and aromatic products reached 13 and 21%, respectively.…”

Section: Resultsmentioning

confidence: 99%

Release Mechanism of Volatile Products from Oil Shale Pressure-Controlled Pyrolysis Induced by Supercritical Carbon Dioxide

Zhao

et al. 2022

ACS Omega

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The compactness of the oil shale reservoir and the complexity of the pore structure lead to the secondary reaction of kerogen in the process of hydrocarbon expulsion, which reduces the effective recovery of shale oil. In this paper, supercritical carbon dioxide was used as a heat carrier and a displacement medium. In a self-designed fluidized bed experimental system for pressure-controlled pyrolysis of oil shale, the experiments of oil shale pyrolysis under standard atmospheric pressure and 7.8–8.0 MPa pressure in nitrogen and carbon dioxide atmospheres were completed. The extraction efficiency of supercritical carbon dioxide at low temperature is obvious, but with the increase of temperature, the effect of extraction on pyrolysis is lower than that of temperature. Under a nitrogen atmosphere, the secondary reaction of shale oil is mainly secondary pyrolysis and aromatization. However, in a supercritical carbon dioxide atmosphere, the main reactions are secondary addition and aromatization. In addition, compared with that in the standard atmospheric pressure, it was found that the olefin synthesis reaction was obviously inhibited under a high-pressure nitrogen or supercritical carbon dioxide atmosphere.

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“…But the oil yield is reduced, which leads to higher gas yield and coke formation on the catalyst. The total nitrogen and sulfur contents in oil were significantly reduced by 67% for nitrogen and 56% for sulfur [ 30 ]. Chang et al [ 31 ] conducted catalytic pyrolysis of Huadian oil shale using ZSM-5 (SAR = 25, 38, 50) as a catalyst.…”

Section: Research Progress On Catalytic Pyrolysis Of Oil Shalementioning

confidence: 99%

Progress in Catalytic Pyrolysis of Oil Shale

Pan

et al. 2021

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This paper briefly describes the research status of oil shale pyrolysis technology and the main factors affecting oil shale pyrolysis, with emphasis on four kinds of commonly used catalysts: The effects of natural minerals, metal compounds, molecular sixes, and supported catalysts on the pyrolysis of oil shale were discussed. The changes of the pyrolysis mechanism and product composition of oil shale with the addition of different catalysts were discussed. Finally, the development direction of preparation of new catalysts was discussed, in order to provide a prospect for the development and utilization of unconventional and strategic alternative energy resources around the world.

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Characteristics of oil shale pyrolysis in a two-stage fluidized bed

Cited by 19 publications

References 22 publications

Studies of the Bubbling Fluidized Bed Retorting of Dachengzi Oil Shale: 1. Effect of Retorting Temperature

Studies of the Bubbling Fluidized Bed Retorting of Dachengzi Oil Shale: 1. Effect of Retorting Temperature

Release Mechanism of Volatile Products from Oil Shale Pressure-Controlled Pyrolysis Induced by Supercritical Carbon Dioxide

Progress in Catalytic Pyrolysis of Oil Shale

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