Study on the Characteristics of the Oil Shale and Shale Char Mixture Pyrolysis

Yan, Junwei; Jiang, Xiumin; Han, Xiangxin

doi:10.1021/ef9008345

Cited by 36 publications

(26 citation statements)

References 19 publications

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“…Previous studies 21−23 reported that CH 4 is related to the breakage and hydrogenation of methyl chains in oil, while H 2 is from the breakage of C−H bonds and other hydrogen sources. We suggest the catalytic cracking of aliphatic hydrocarbons containing in shale oil for the increased production of CH 4 and H 2 . Figure 3 compares the gas chromatography-mass spectrometry (GC-MS) analysis results of shale oils at different pyrolysis volatile residence times in the shale ash bed.…”

Section: Resultsmentioning

confidence: 88%

“…Thus, the physical and chemical interactions between shale ash and oil shale have to impact the oil shale pyrolysis behavior and affect the pyrolysis product through secondary reactions including cracking and coking between pyrolysis volatiles and ash. 4,5 It is predicted that shale oil cracking could be significant in the SHC process to either decompose or upgrade the shale oil over shale ash. 6,7 The primary volatile released from pyrolyzing oil shale can adhere to the surface of shale ash particles to lead to secondary reactions toward the released volatile.…”

Section: Introductionmentioning

confidence: 99%

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Secondary Cracking and Upgrading of Shale Oil from Pyrolyzing Oil Shale over Shale Ash

et al. 2015

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Considering oil shale pyrolysis with a solid heat carrier, this article investigated the effect of shale ash, as the bed material for secondary reactions of pyrolysis volatile, on final product distribution and quality of oil shale pyrolysis in a laboratory dual-stage fixed bed reactor. The examined factors included the residence time of pyrolysis volatile in a shale ash bed and the temperature of shale ash (i.e., cracking temperature). Prolonging the pyrolysis volatile residence time in the shale ash bed from 0 to 10 s decreased the shale oil yield by 31.0% but increased the fraction of gasoline and diesel (boiling point <623 K) by 46.4%. A part of heavy oil (boiling point >773 K) was cracked to increase the yields of light oil and pyrolysis gas (especially H 2 and CH 4 ). The shale ash bed temperature was the key factor affecting the product distribution. The catalytic effect of shale ash lowered the shale oil cracking temperature for achieving the same degree of oil cracking. The catalytic activity of shale ash for cracking shale oil was shown to be closely dependent on the metal oxides in the ash. While CaO and Na 2 O tended to inhibit the formation of coke and to promote catalytic reforming, Fe 2 O 3 showed good activity in cracking shale oil and forming coke.

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Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Secondary Cracking and Upgrading of Shale Oil from Pyrolyzing Oil Shale over Shale Ash

et al. 2015

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“…The third stage, 540-650 • C, had a weight loss of 1.7% with no obvious weight loss peak. Weight loss in the third stage is related to the decomposition of inorganic matter, especially the decomposition of clay minerals [51]. …”

Section: Preparation Of Oil Shale Samplesmentioning

confidence: 99%

Influence of In Situ Pyrolysis on the Evolution of Pore Structure of Oil Shale

Liu

Yang

et al. 2018

Energies

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The evolution of pore structure during in situ underground exploitation of oil shale directly affects the diffusion and permeability of pyrolysis products. In this study, on the basis of mineral analysis and thermogravimetric results, in combination with the low-pressure nitrogen adsorption (LPNA) and mercury intrusion porosimetry (MIP) technique, the evolution of pore structure from 23 to 650 • C is quantitatively analyzed by simulating in situ pyrolysis under pressure and temperature conditions. Furthermore, based on the experimental results, we analyze the mechanism of pore structure evolution. The results show the following: (1) The organic matter of Fushun oil shale has a degradation stage in the temperature range of 350-540 • C, and there is no obvious temperature gradient between decomposition of kerogen and the secondary decomposition of bitumen. The thermal response mechanisms of organic matter and minerals are different in each temperature stage, and influence the change of pore structure. (2) Significant changes occur in pore shape at 350 • C, where thermal decomposition of kerogen begins. The ink-bottle pores are dominant when the temperature is less than 350 • C, whereas slit pores dominate when the temperature is greater than 350 • C. (3) The change in pore structure of oil shale is much less significant from 23 to 350 • C. The pore volume, porosity, and specific surface area (SSA) of samples increase rapidly with temperature varying from 350 to 600 • C. The variation of each parameter is dissimilated from 600 to 650 • C: the porosity and pore volume increases with a small gradient from 600 to 650 • C, and SSA decreases significantly. (4) The lithostatic pressure does not cause change in the evolution discipline of the pore structure, but the inhibitory effect on the pore development is significant.

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“…In the early stage of oil shale pyrolysis (<200 • C), the heat of the oil shale layer is mainly used to evaporate the interbedded and adsorbed water of clay minerals [31][32][33][34]. To shorten the time of oil shale dehydration, heater H50 is the best choice for heating an oil shale reservoir in the preheating stage.…”

Section: Comprehensive Performancementioning

confidence: 99%

“…In the second stage of oil shale pyrolysis (300-550 • C), kerogen is converted into oil. In the third stage (>600 • C), carbonate and clay minerals decompose [31][32][33][34]. To make full use of the heat injected into an oil shale formation and produce more oil, the heater H50 with a packer at its outlet should be selected to maintain the oil shale in the second stage of pyrolysis.…”

Section: Performance Evaluation Based On the Second Law Of Thermodynamentioning

confidence: 99%

Effects of Packer Locations on Downhole Electric Heater Performance: Experimental Test and Economic Analysis

et al. 2020

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A downhole electric heater, which reduces heat loss along a heat insulation pipe, is a key apparatus used to ignite oil shale underground. Downhole heaters working together with packers can improve the heating efficiency of high-temperature gases, while different packer locations will directly affect the external air temperature of the heater shell and, subsequently, the performance and total cost of the downhole heaters. A device was developed to simulate the external conditions of heater shells at different packer locations. Then, the effects of external air temperature on the performance of a downhole heater with pitches of 50, 160, and 210 mm were experimentally studied. In the test, results indicated that the heater with a packer at its outlet had an accelerated heating rate in the initial stage and decreased temperature in the final stage. Additionally, the lowest heating rod surface temperature and highest comprehensive performance were achieved with minimal irreversible loss and lower total cost when using a downhole electric heater with a packer set at its outlet. In addition, the downhole electric heater with a helical pitch of 50 mm and a packer at its outlet was more effective than other schemes in the high Reynolds number region. These findings are beneficial for shortening the oil production time in oil shale in situ pyrolysis and heavy oil thermal recovery.

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Study on the Characteristics of the Oil Shale and Shale Char Mixture Pyrolysis

Cited by 36 publications

References 19 publications

Secondary Cracking and Upgrading of Shale Oil from Pyrolyzing Oil Shale over Shale Ash

Secondary Cracking and Upgrading of Shale Oil from Pyrolyzing Oil Shale over Shale Ash

Influence of In Situ Pyrolysis on the Evolution of Pore Structure of Oil Shale

Effects of Packer Locations on Downhole Electric Heater Performance: Experimental Test and Economic Analysis

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