Article
Energy & Fuels
Dengke Wang, Fanchao Zeng, Jianping Wei, Hongtu Zhang, Yan Wu, Qiang Wei
Summary: The study investigates the dynamic evolution of fractures in coal under different compressive loads using X-ray computer tomography. Results show that confining pressure and minerals significantly impact fracture propagation in coal, and fractal dimension can quantitatively characterize the evolution process of three-dimensional fractures.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Chemical
Yinghao Zhu, Yineng Tan, Songhang Zhang, Mengdie Wang, Bingyi Wang
Summary: Understanding the evolution of pore-fracture networks in coal during loading is crucial for coalbed methane exploration. This study conducted uniaxial compression experiments on coal samples and used mu-CT scanning to visualize the crack network model. The results revealed the propagation of initial cleats and micro-cracks in the dominant crack direction and the subsequent process of crack merging. These insights provide valuable information for improving strategies for coalbed methane extraction.
Article
Chemistry, Multidisciplinary
Zhiqi Wang, Xufei Gong, Xuebin Gu
Summary: By conducting triaxial compression tests on fractured coal specimens, the research investigates the mechanical properties, failure characteristics, fractal characteristics, and energy evolution law of shallow fractured coal in the Western China mining area. The results reveal the changes in stress-strain curve, mechanical properties, failure mode, and energy evolution with the increase of prefabricated crack number. The findings contribute to a better understanding of the failure mechanism of fractured coal and its application in control design.
APPLIED SCIENCES-BASEL
(2022)
Article
Geosciences, Multidisciplinary
Rongxi Shen, Zhoujie Gu, Zhentang Liu, Enlai Zhao, Zesheng Zang, Xin Zhou, Xiaoliang Li, Wei Liu, Xi Wang
Summary: A full understanding of the dynamic mechanical characteristics of coal samples under true triaxial conditions is crucial for preventing and controlling dynamic disasters in deep coal and rock. The study found that the transmission amplitude decreases as sigma 1 increases and increases with the impact velocity. The peak stress and absorbed energy of coal decrease with the increase in sigma 1 under true triaxial conditions. Under uniaxial and true triaxial conditions, the peak stress and absorbed energy of coal increase with the increase in impact velocity, and the stress change under true triaxial conditions is more sensitive to the dynamic load. Compared to uniaxial impact, the damage degree of coal samples under true triaxial conditions is lower. The fractal dimension of broken blocks increases linearly with the increase in sigma 1 and dynamic load, indicating an intensified degree of broken coal. This study effectively reveals the failure mechanism of coal under unequal static load and dynamic load.
NATURAL RESOURCES RESEARCH
(2023)
Article
Energy & Fuels
D. Zeinabady, C. R. Clarkson, S. Razzaghi, S. Haqparast, A. L. Benson, M. Azad
Summary: The objective of this study is to develop a diagnostic tool, using the DFIT-FBA method, to identify the existence of faults, pre-existing hydraulic fractures, and depleted areas in order to address challenges in developing unconventional reservoirs with multifractured horizontal wells. The results demonstrate that reservoir heterogeneities, such as faults, can be identified through multiple cycles of the DFIT-FBA method at a single point or by applying multiple DFIT-FBAs at different points along the lateral section of a horizontal well or at different wells.
SPE RESERVOIR EVALUATION & ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Zhiliang Wang, Songyu Li, Jianguo Wang, Feng Xiong, Lixiang Xie
Summary: Triaxial compression tests were conducted on deep-buried marble to investigate its deformation and failure characteristics under high in-situ stress. The results showed that increasing the confining pressure enhances the strength and deformation of marble samples. The failure mode transitions from brittleness to shear failure with increasing confining pressure. The energy evolution during the deformation process can be divided into different phases: hardening, energy storage, damage softening, and residual phases.
INTERNATIONAL JOURNAL OF DAMAGE MECHANICS
(2022)
Article
Chemistry, Multidisciplinary
Yawu Shao, Yonglu Suo, Jiang Xiao, Yuan Bai, Tao Yang, Siwei Fan
Summary: The dynamic evolution characteristics of fractures in coal and rock mass play a crucial role in analyzing the development of instability, gas diffusion, and dynamic disaster prediction. Experimental results show that damage to coal mass due to high-pressure oil diffusion is inversely correlated with the distance from the disaster source. Furthermore, in abandoned oil wells, as the coal mass gets closer to the disaster source, its mechanical performance diminishes, fracture volume increases, and oil and gas storage capacity improves.
APPLIED SCIENCES-BASEL
(2022)
Article
Geosciences, Multidisciplinary
Zhoujie Gu, Rongxi Shen, Zhentang Liu, Enlai Zhao, Hailiang Chen, Zichen Yuan, Xiaomeng Chu, Jiawei Tian
Summary: Dynamic failure experiments were conducted on coal samples under dynamic load in a triaxial Split-Hopkinson pressure bar test system to study the dynamic characteristics of coal in a multi-axial pre-stress state. The experiments showed that the 3D pre-stress state significantly affects the dynamic failure of coal. The dynamic initial stress of coal increases linearly with strain, then grows at a reduced rate until the peak strength, and the mechanical curve rebounds notably. The dynamic strength factors of coal vary significantly with the increase of confining pressure.
NATURAL RESOURCES RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Yubing Liu, Enyuan Wang, Changbao Jiang, Dongming Zhang, Minghui Li, Beichen Yu, Dong Zhao
Summary: During deep underground coal mining, the mechanical and permeability characteristics of initially fractured coal were investigated under true triaxial stresses. The results show that initially fractured coal exhibits semi-brittle Class I failure modes and forms new failure planes different from intact coal samples. The peak strength of initially fractured coal is observed when the maximum principal stress is perpendicular to bedding planes, while minimum values occur when the maximum principal stress is parallel to butt cleats. The permeability of initially fractured coal decreases due to the presence of pulverized coal grains.
NATURAL RESOURCES RESEARCH
(2023)
Article
Construction & Building Technology
Prodip Kumar Sarkar, Nilanjan Mitra
Summary: This study examines the molecular deformation response of the mineral analogue to hydrated cement paste under uni/tri-axial loading using empirical and reactive force fields. A comparison of responses using different force fields is conducted, with a focus on the evolution of atomic environment during deformation. Key observations on the application of different force fields for studying the material's large deformation behavior are highlighted.
CEMENT AND CONCRETE RESEARCH
(2021)
Article
Geochemistry & Geophysics
Rui Yang, Lv Jiakun, Bo Zhou, Depeng Ma
Summary: The mechanical response characteristics and occurrence mechanism of coal and rock under unloading conditions are crucial for evaluating the stability and control of rock excavation in engineering. Fractal characteristics of coal and rock acoustic emission time series were analyzed to predict the unloading failure of coal and rock. In addition, the HURST index was calculated to determine the unloading and fracture process of rock samples.
Article
Engineering, Geological
Yiteng Du, Tingchun Li, Binxu Wang, Shilin Zhang, Hui Li, Hao Zhang, Qingwen Zhu
Summary: Triaxial seepage tests were conducted on sandstone specimens with different fissure filling states to investigate the impact of fillings on mechanics, fracture behavior, and permeability evolution during seepage stress-induced failure. Results show that fillings have a greater enhancing effect on stress thresholds for low-dip fissures compared to high-dip fissures. Mud and sand fillings affect crack initiation angles and change failure types, especially in high-dip fissure specimens. Additionally, the crack paths, damage extent, and permeability evolution are influenced by fillings and water pressure.
Article
Acoustics
Kun Zhang, Sen Zhang, Jianxi Ren, Man Wang, Shuai Jing, Weijun Zhang
Summary: In this paper, a rock dynamic and static triaxial mechanical test system is used to study the evolution law of acoustic emission (AE) b value of coal rock under varying frequencies of static and dynamic load. The results show that dynamic load disturbance accelerates the instability failure process of coal rock, while the average stress level/ultimate strain of coal rock correspondingly declines/rises with increasing dynamic load frequency. The overall AE b value is relatively low after dynamic load disturbance, and the decrease in b value is larger with higher dynamic load frequency. Additionally, the change rule of AE b value is closely related to the instability and failure process of coal rock.
SHOCK AND VIBRATION
(2023)
Article
Engineering, Chemical
Guorui Feng, Yidie Zhang, Zhen Li, Zhilong Fang, Yanqun Yang, Xiaohong Yang, Xiangming Zhang
Summary: The compaction and re-crushing degree of crushed coal differ at different heights due to the compaction of the overburden strata, which is called layered re-crushing. Quantitative characterization of layered re-crushing of coal particles during compression is achieved in this study. The results show that the degree of particle re-crushing decreases from the upper layer to the lower layer, and the particle diameter distribution transfers to a smaller diameter faster in the upper layer and slower in the lower layer.
Article
Mathematics, Interdisciplinary Applications
Zhen Zhang, Gaofeng Liu, Xiaoming Wang, Baolin Li, Huan Liu
Summary: This paper proposes a method for fractal characterization of fracture volume in coal based on CT scanning experiment. It derives the relation among fractal dimension D, fracture volume, and length scale. The results demonstrate that fracture volume comprehensively embodies the height, length, and aperture of fracture. Therefore, further research on establishing an analytical equation based on D for fluid transport characteristics in porous media is worth exploring.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2022)
Article
Chemistry, Physical
Deng-Ke Wang, Shu-Min Liu, Jian-Ping Wei, Hong-Lei Wang, Bang-Hua Yao
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2017)
Article
Energy & Fuels
Dengke Wang, Ping Zhang, Jianping Wei, Chong Yu
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2020)
Article
Energy & Fuels
Xin Bai, Dongming Zhang, Sheng Zeng, Shuwen Zhang, Dengke Wang, Fulin Wang
Article
Multidisciplinary Sciences
Hongtu Zhang, Dengke Wang, Chong Yu, Jianping Wei, Shumin Liu, Jianhua Fu
Article
Geochemistry & Geophysics
Yan Wu, Dengke Wang, Xiaofei Pang, Hang Zhang
Summary: In this study, the evolution process of internal defects in coal, such as pores and fissures, was visualized using a combination of real-time computed tomography (CT) scanning test and loading test. A CT image similarity retrieval method was proposed to address the influence of axial deformation on fracture analysis. The results showed that the proposed method accurately characterized the fracture distribution and dynamic evolution law of the coal sample. Three fracture evolution stages were observed under triaxial stress: closure during compaction and elastic stages, initiation and development during the plastic yield stage, and rapid expansion and penetration during the postpeak stage. The analysis helps clarify the coal failure mechanism under triaxial stress.
Article
Geochemistry & Geophysics
Kai Wang, Xiang Zhang, Haijun Guo, Qiang Fu, Dengke Wang, Hang Zhang, Fangchao Lu
Summary: This study reveals the propagation law of hydraulic fractures in the immediate roof of soft outburst coal seam and the changes in microstructure after hydraulic fracturing. Experimental results show that the bedding angle significantly affects the extension of hydraulic fractures, which are determined by both internal fractures and the cementation strengths of the bedding planes. The findings provide guidance for the design and application of hydraulic fracturing in the immediate roof of soft outburst coal seam.
Article
Mathematical & Computational Biology
Jinxia Yu, Chengyi Wu, Yingying Li, Yimin Zhang
Summary: This paper proposes a segmentation method for coal crack CT images and establishes a corresponding dataset. The method utilizes a deep learning model structure and intelligently extracts cracks through modifications in network parameters and the definition of a new loss function. Compared with other techniques and the original model, this method achieves higher accuracies and IOU values, making it suitable for practical applications in safety engineering.
COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE
(2022)
Article
Energy & Fuels
Yingna Du, Chen Huang, Wei Jiang, Qiangwei Yan, Yongfei Li, Gang Chen
Summary: In this study, anionic surfactants modified hydrotalcite was used as a flow improver for crude oil under low-temperature conditions. The modified hydrotalcite showed a significant viscosity reduction effect on crude oil. The mechanism of the modified hydrotalcite on viscosity and pour point of crude oil was explored through characterization and analysis of the modified hydrotalcite and oil samples.
Article
Energy & Fuels
Mohammad Saeid Rostami, Mohammad Mehdi Khodaei
Summary: In this study, a hybrid structure, MIL-53(Al)@MWCNT, was synthesized by combining MIL-53(Al) particles and -COOH functionalized multi-walled carbon nanotube (MWCNT). The hybrid structure was then embedded in a polyethersulfone (PES) polymer matrix to prepare a mixed matrix membrane (MMM) for CO2/CH4 and CO2/N2 separation. The addition of MWCNTs prevented MIL-53(Al) aggregation, improved membrane mechanical properties, and enhanced gas separation efficiency.
Article
Energy & Fuels
Yunlong Li, Desheng Huang, Xiaomeng Dong, Daoyong Yang
Summary: This study develops theoretical and experimental techniques to determine the phase behavior and physical properties of DME/flue gas/water/heavy oil systems. Eight constant composition expansion (CCE) tests are conducted to obtain new experimental data. A thermodynamic model is used to accurately predict saturation pressure and swelling factors, as well as the phase boundaries of N2/heavy oil systems and DME/CO2/heavy oil systems, with high accuracy.
Article
Energy & Fuels
Morteza Afkhamipour, Ebad Seifi, Arash Esmaeili, Mohammad Shamsi, Tohid N. Borhani
Summary: Non-conventional amines are being researched worldwide to overcome the limitations of traditional amines like MEA and MDEA. Adequate process and thermodynamic models are crucial for understanding the applicability and performance of these amines in CO2 absorption, but studies on process modeling for these amines are limited. This study used rate-based modeling and Deshmukh-Mather method to model CO2 absorption by DETA solution in a packed column, validated the model with experimental data, and conducted a sensitivity analysis of mass transfer correlations. The study also compared the CO2 absorption efficiency of DETA solution with an ionic solvent [bmim]-[PF6] and highlighted the importance of finding optimum operational parameters for maximum absorption efficiency.
Article
Energy & Fuels
Arastoo Abdi, Mohamad Awarke, M. Reza Malayeri, Masoud Riazi
Summary: The utilization of smart water in EOR operations has gained attention, but more research is needed to understand the complex mechanisms involved. This study investigated the interfacial tension between smart water and crude oil, considering factors such as salt, pH, asphaltene type, and aged smart water. The results revealed that the hydration of ions in smart water plays a key role in its efficacy, with acidic and basic asphaltene acting as intrinsic surfactants. The pH also influenced the interfacial tension, and the aged smart water's interaction with crude oil depended on asphaltene type, salt, and salinity.
Article
Energy & Fuels
Dongao Zhu, Kun Zhu, Lixian Xu, Haiyan Huang, Jing He, Wenshuai Zhu, Huaming Li, Wei Jiang
Summary: In this study, cobalt-based metal-organic frameworks (Co-based MOFs) were used as supports and co-catalysts to confine the NHPI catalyst, solving the leaching issue. The NHPI@Co-MOF with carboxyl groups exhibited stronger acidity and facilitated the generation of active oxygen radicals O2•, resulting in enhanced catalytic activity. This research provides valuable insights into the selection of suitable organic linkers and broadens the research horizon of MOF hybrids in efficient oxidative desulfurization (ODS) applications.
Article
Energy & Fuels
Edwin G. Hoyos, Gloria Amo-Duodu, U. Gulsum Kiral, Laura Vargas-Estrada, Raquel Lebrero, Rail Munoz
Summary: This study investigated the impact of carbon-coated zero-valent nanoparticle concentration on photosynthetic biogas upgrading. The addition of nanoparticles significantly increased microalgae productivity and enhanced nitrogen and phosphorus assimilation. The presence of nanoparticles also improved the quality of biomethane produced.
Article
Energy & Fuels
Yao Xiao, Asma Leghari, Linfeng Liu, Fangchao Yu, Ming Gao, Lu Ding, Yu Yang, Xueli Chen, Xiaoyu Yan, Fuchen Wang
Summary: Iron is added as a flocculant in wastewater treatment and the hydrothermal carbonization (HTC) of sludge produces wastewater containing Fe. This study investigates the effect of aqueous phase (AP) recycling on hydrochar properties, iron evolution and environmental assessment during HTC of sludge. The results show that AP recycling process improves the dewatering performance of hydrochar and facilitates the recovery of Fe from the liquid phase.
Article
Energy & Fuels
He Liang, Tao Wang, Zhenmin Luo, Jianliang Yu, Weizhai Yi, Fangming Cheng, Jingyu Zhao, Xingqing Yan, Jun Deng, Jihao Shi
Summary: This study investigated the influence of inhibitors (carbon dioxide, nitrogen, and heptafluoropropane) on the lower flammability limit of hydrogen and determined the critical inhibitory concentration needed for complete suppression. The impact of inhibitors on explosive characteristics was evaluated, and the inhibitory mechanism was analyzed with chemical kinetics. The results showed that with the increase of inhibitor quantity, the lower flammability limit of hydrogen also increased. The research findings can contribute to the safe utilization of hydrogen energy.
Article
Energy & Fuels
Zonghui Liu, Zhongze Zhang, Yali Zhou, Ziling Wang, Mingyang Du, Zhe Wen, Bing Yan, Qingxiang Ma, Na Liu, Bing Xue
Summary: In this study, high-performance solid catalysts based on phosphotungstic acid (HPW) supported on Zr-SBA-15 were synthesized and evaluated for the one-pot conversion of furfural (FUR) to γ-valerolactone (GVL). The catalysts were characterized using various techniques, and the ratio of HPW and Zr was found to significantly affect the selectivity of GVL. The HPW/Zr-SBA-15 (2-4-15) catalyst exhibited the highest GVL yield (83%) under optimized reaction conditions, and it was determined that a balance between Bronsted acid sites (BAS) and Lewis acid sites (LAS) was crucial for achieving higher catalytic performance. The reaction parameters and catalyst stability were also investigated.
Article
Energy & Fuels
Michael Stoehr, Stephan Ruoff, Bastian Rauch, Wolfgang Meier, Patrick Le Clercq
Summary: As part of the global energy transition, an experimental study was conducted to understand the effects of different fuel properties on droplet vaporization for various conventional and alternative fuels. The study utilized a flow channel to measure the evolution of droplet diameters over time and distance. The results revealed the temperature-dependent effects of physical properties, such as boiling point, liquid density, and enthalpy of vaporization, and showed the complex interactions of preferential vaporization and temperature-dependent influences of physical properties for multi-component fuels.
Article
Energy & Fuels
Yuan Zhuang, Ruikang Wu, Xinyan Wang, Rui Zhai, Changyong Gao
Summary: Through experimental validation and optimization of the chemical kinetic model, it was found that methanol can accelerate the oxidation reaction of ammonia, and methanol can be rapidly oxidized at high concentration. HO2 was found to generate a significant amount of OH radicals, facilitating the oxidation of methanol and ammonia. Rating: 7.5/10.
Article
Energy & Fuels
Radwan M. EL-Zohairy, Ahmed S. Attia, A. S. Huzayyin, Ahmed I. EL-Seesy
Summary: This paper presents a lab-scale experimental study on the impact of diethyl ether (DEE) as an additive to waste cooking oil biodiesel with Jet A-1 on combustion and emission features of a swirl-stabilized premixed flame. The addition of DEE to biodiesel significantly affects the flame temperature distribution and emissions. The W20D20 blend of DEE, biodiesel, and Jet A-1 shows similar flame temperature distribution to Jet A-1 and significantly reduces UHC, CO, and NOx emissions compared to Jet A-1.
Article
Energy & Fuels
Jiang Bian, Ziyuan Zhao, Yang Liu, Ran Cheng, Xuerui Zang, Xuewen Cao
Summary: This study presents a novel method for ammonia separation using supersonic flow and develops a mathematical model to investigate the condensation phenomenon. The results demonstrate that the L-P nucleation model accurately characterizes the nucleation process of ammonia at low temperatures. Numerical simulations also show that increasing pressure and concentration can enhance ammonia condensation efficiency.
Article
Energy & Fuels
Shiyuan Pan, Xiaodan Shi, Beibei Dong, Jan Skvaril, Haoran Zhang, Yongtu Liang, Hailong Li
Summary: Integrating CO2 capture with biomass-fired combined heat and power (bio-CHP) plants is a promising method for achieving negative emissions. This study develops a reliable data-driven model based on the Transformer architecture to predict the flowrate and CO2 concentration of flue gas in real time. The model validation shows high prediction accuracy, and the potential impact of meteorological parameters on model accuracy is assessed. The results demonstrate that the Transformer model outperforms other models and using near-infrared spectral data as input features improves the prediction accuracy.