Economic and heating efficiency analysis of double-shell downhole electric heater for tar-rich coal in-situ conversion

Wang, Zhendong; Yang, Fu; Fu, Deliang; Ma, Li; Duan, Zhonghui; Wang, Qiuwang; Kang, Shijie; Guo, Wei

doi:10.1016/j.csite.2022.102596

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…Wang conducted a numerical analysis on the performance of a combined multi-shell continuous helical baffle heat exchanger. Under similar mass flow rates and heat exchange quantities, the combined multi-shell heat exchanger exhibited a 13% lower average pressure drop compared to it [34,35].…”

Section: Introductionmentioning

confidence: 99%

Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Bu,

Li,

2024

Applied Sciences

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Downhole heaters are critical for effectively achieving in situ oil shale cracking. In this study, we simulate the heat transfer performance of a large-scale helical baffle downhole heater under various operational conditions. The findings indicate that at 160 m3/h and 6 kW the outlet temperature can reach 280 °C. Controlling heating power or increasing the injected gas flow effectively mitigates heat accumulation on the heating rod’s surface. The outlet temperature curve exhibits two phases. Simultaneously, a balance in energy exchange between the injected gas and heating power occurs, mitigating high-temperature hotspots. Consequently, the outlet temperature cannot attain the theoretical maximum temperature, referred to as the actual maximum temperature. Employing h/∆p13 as the indicator to evaluate heat transfer performance, optimal performance occurs at 100 m3/h. Heat transfer performance at 200 m3/h is significantly impacted by heating power, with the former being approximately 6% superior to the latter. Additionally, heat transfer performance is most stable below 160 m3/h. The gas heating process is categorized into three stages based on temperature distribution characteristics within the heater: rapid warming, stable warming, and excessive heating. The simulation findings suggest that the large-size heater can inject a higher flow rate of heat-carrying gas into the subsurface, enabling efficient oil shale in situ cracking.

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Section: Introductionmentioning

confidence: 99%

Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Bu,

Li,

2024

Applied Sciences

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“…With the continuous development of oil shale extraction technology, in situ heating of oil shale has emerged as a new direction in oil shale development . In situ heating of oil shale involves the conversion of electrical energy into heat energy, which is then used to heat the oil shale formation through conduction or the generation of high-temperature fluids . Compared to traditional retorting techniques, in situ heating of oil shale offers significant advantages.…”

Section: Introductionmentioning

confidence: 99%

“… 4 In situ heating of oil shale involves the conversion of electrical energy into heat energy, which is then used to heat the oil shale formation through conduction or the generation of high-temperature fluids. 5 Compared to traditional retorting techniques, in situ heating of oil shale offers significant advantages. It improves recovery efficiency, reduces operational costs, and minimizes the environmental impact.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Enhanced Heat Transfer of Downhole Slotted-Type Heaters for In Situ Oil Shale Exploitation

Sun,

Liu,

Yan

et al. 2023

ACS Omega

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In order to improve the flow state of the heater shell side and enhance the performance evaluation of the heater, this paper proposes a perforated plate-type heater model. Based on Fluent, numerical studies are conducted on the heat transfer performance and shell-side fluid flow characteristics of a perforated plate-type heater. The variations of the heat transfer factor Nu, friction factor f, and evaluation parameter Nu/f 1/3 are analyzed for different helix angles β and ratios of the long and short semiaxes of the circular holes on the heating plate under different Reynolds numbers Re. The results reveal that under the same shell-side Reynolds number Re, the heat transfer factor Nu shows an increasing trend with the increase in the proportion of the helix angle β. The heat transfer factor Nu for the heating plate with the hole shape ratio a/b = 1 does not exhibit significant improvement compared to hole shape ratios a/b = 0.8 and a/b = 0.6, but it increases by 4.87 to 7.07% compared to the hole shape ratio a/b = 0.4 in the perforated plate-type heater. On the other hand, the friction factor f decreases as the helix angle β and the ratio of hole shapes on the heating plate increase. The lowest friction factor f is observed for the helix angle β of 25°and the hole shape ratio a/b = 1 in the perforated plate-type heater. When the helix angle β is 25°and the hole shape ratio is a/b = 1, the evaluation parameter Nu/f 1/3 reaches its highest value, indicating the optimal overall performance of the perforated plate-type heater.

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“…It is a special coal resource that integrates coal and oil properties [1]. In situ pyrolysis of tar-rich coal is a new production method of directly heating the original coal reservoir through heat carriers to promote the underground pyrolysis of tar-rich coal [2]. During the chemical process of pyrolysis, the heat is transferred from the heat carrier injected through the inlet well to the coal reservoir, and the reaction occurs after the local temperature of the coal is higher than the pyrolysis temperature.…”

Section: Introductionmentioning

confidence: 99%

Rapid Prediction of the In Situ Pyrolysis Performance of Tar-Rich Coal Using the POD Method

Wang,

Ye,

et al. 2023

Processes

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In this paper, a POD reduced-order interpolation model for solving the in situ pyrolysis process of tar-rich coal is employed to predict the flow and heat transfer performance in the porous media region so as to save computational resources and realize fast calculations. Numerical simulation using the finite volume method (FVM) is firstly used to obtain sample data, based on the samples through the primary function and spectral coefficients of the solutions. The physical field information and parameter distribution under different conditions of inlet temperature, inlet velocity and permeability are predicted. The results are compared with those of FVM to verify the accuracy of the calculated results. The relative mean deviation (RME) of the results of the POD prediction of each parameter for each working condition was synthesized to be no more than 5%. The performance of in situ pyrolysis of tar-rich coal is then investigated, and the oil and gas production are predicted. As the inlet velocity increases from 0.3 m/s to 0.9 m/s, the fraction of high-quality oil and gas production reaches 0.47 and then decreases to 0.38. Increasing the inlet temperature and permeability has a negative effect on the fraction of high-quality hydrocarbon production, after which the quality fraction of high-quality oil and gas dropped sharply to about 0.22. Porosity has a positive impact on the oil and gas production. When the porosity reaches 0.3, the quality fraction of high-quality oil and gas can reach 0.27.

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Economic and heating efficiency analysis of double-shell downhole electric heater for tar-rich coal in-situ conversion

Cited by 9 publications

References 11 publications

Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Numerical Study on Enhanced Heat Transfer of Downhole Slotted-Type Heaters for In Situ Oil Shale Exploitation

Rapid Prediction of the In Situ Pyrolysis Performance of Tar-Rich Coal Using the POD Method

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