Article
Chemistry, Physical
Krzysztof Kapusta, Marian Wiatowski, Hywel R. Thomas, Renato Zagorscak, Sivachidambaram Sadasivam, Shakil Masum, Thomas Kempka, Christopher Otto, Wioleta Basa, Marcin Szyja, Krzysztof Stanczyk
Summary: This paper presents a series of surface experimental simulations of methane-oriented underground coal gasification using hydrogen as gasification medium. The experiments demonstrated that the physicochemical properties of coal considerably affect the hydrogasification process and the feasibility of methane-rich gas production was initially demonstrated. However, further techno-economic studies are necessary to assess the economic feasibility of methane production using this process.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Review
Energy & Fuels
Shadrack Adjei Takyi, Yindi Zhang, Mengting Si, Fanjin Zeng, Yingnan Li, Paitoon Tontiwachwuthikul
Summary: Although coal mining has played a significant role in global development, its environmental impact offsets its value. The shift to net-zero CO2 emissions presents opportunities for new coal technological models. This paper reviews the current status and technology development of underground coal gasification for low carbon emission energy, discussing its modern stage, pilot operations, and market developments.
FRONTIERS IN ENERGY RESEARCH
(2023)
Article
Energy & Fuels
Yanpeng Chen, Tianduoyi Wang, Jinhua Zhang, Mengyuan Zhang, Junjie Xue, Juntai Shi, Yongshang Kang, Shengjie Li
Summary: This study aims to address the issues of gasification failure, environmental pollution, and low calorific value in underground coal gasification. By establishing a geological model and simulating the migration of different gases, some relevant patterns are identified, and pressure distribution characteristics are presented. These findings are of great significance for guiding the design of operational parameters and monitoring well deployment, ensuring the safety and reliability of on-site gasification.
Article
Mathematics
Afaq Ahmed, Syed Bilal Javed, Ali Arshad Uppal, Jamshed Iqbal
Summary: The Cavity Simulation Model (CAVSIM) is a 3D, parameterisable simulator of the Underground Coal Gasification Process (UCG) that serves as a benchmark for UCG prediction. It has limitations in graphical capabilities, parametrisation efficiency, and lack of tools to synthesise a controller. To compensate for these shortcomings, CAVSIM was integrated with MATLAB, resulting in successful integration and a controllable structure. The performance metrics further establish the efficacy of CAVLAB in designing MPC for the UCG system.
Article
Energy & Fuels
Wen-gang Huang, Zuo-tang Wang, Tian-hong Duan, Lin Xin
Summary: The pilot project integrating UCG with power generation in the abandoned mine Ankou aimed to optimize the gasification process, with industrial tests revealing that changes in oxygen concentration significantly affected syngas production. Increasing oxygen concentration led to higher H-2 content, combustible components, calorific value of syngas, and gasification efficiency after an initial drop. Additionally, oxygen-enriched gasification trials showed advantages in air consumption, coal consumption, and calorific value compared to oxygen-enriched steam gasification tests.
Article
Green & Sustainable Science & Technology
Wen-gang Huang, Shao-wei Zhang, Xin Lu, Shu-liang Wu, Jun Huang
Summary: This paper researched the distribution and characteristics of residual coal resources in China and its adaptability to underground coal gasification (UCG) technology. The study found that the average recovery rate of coal mines in China was low, with the majority of residual coal reserves occurring in North China at shallow burial depths. The primary coal type was bituminite. The study established a hierarchical evaluation model and applied it to industrial tests, showing that the model can provide a scientific reference for decision-making in UCG projects.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Thermodynamics
Fa-qiang Su, Xiao-long He, Meng-jia Dai, Jun-nan Yang, Akihiro Hamanaka, Yi-he Yu, Wen Li, Jiao-yuan Li
Summary: This study analyzed the impact of oxygen flow rate on the cavity of the gasification zone through two experiments and used three estimation methods to estimate the cavity volume. The results showed that the stoichiometric method had the smallest estimation error, less than 6.5%. The Delaunay triangulation approach reduced the estimation error for convex cavities to within 10%. The voxelization method reduced the overall estimation error to below 8% and accurately described the cavity shape.
Article
Thermodynamics
Syed Bilal Javed, Ali Arshad Uppal, Raza Samar, Aamer Iqbal Bhatti
Summary: In this work, a model-based multi-variable robust control design using H-infinity technique is proposed for the underground coal gasification (UCG) process. The designed controller based on a linear model demonstrates robust stability and performance on an actual nonlinear cavity simulator, achieving adequate tracking of set points.
Article
Energy & Fuels
Jacek Nowak, Magdalena Kokowska-Pawlowska, Joanna Komorek, Marian Wiatowski, Krzysztof Kapusta, Zdzislaw Adamczyk
Summary: This study conducted coal gasification experiments under different pressures to analyze the changes in optical properties of the organic matter and determine the temperature influence on coal. The results showed that the reflectance and bireflectance of coal decreased with increasing distance from the reactor chamber inlet, and the temperature influence on coal decreased as well. Additionally, the actual temperatures during the experiment were higher than recorded temperatures, and the distance at which temperature had a significant impact depended on the pressure used.
Article
Green & Sustainable Science & Technology
Ni An, Renato Zagorscak, Hywel Rhys Thomas, Wu Gao
Summary: This study improves understanding of potential environmental impact of underground coal gasification by investigating the transport of gaseous and dissolved chemicals in surrounding strata. Results show gas propagation is limited by geological characteristics, and selecting the right coal seam can minimize gas losses and avoid negative environmental impact during operation and decommissioning stages.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Engineering, Geological
Wen-gang Huang, Zuo-tang Wang
Summary: This study focuses on the mechanical performance evolution of coal pillars in the UCG process. A new calculation method for pillar sizing was proposed and experimentally validated, showing significant impact of high temperatures near the coal pillar surface and demonstrating the variation pattern of pillar width during UCG operation.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Energy & Fuels
Krzysztof Kapusta
Summary: Two experimental simulations of underground coal gasification processes were conducted using large bulk samples of lignites, and the results showed that the physicochemical properties of the lignite used considerably affect the in situ gasification process. Lignites with lower moisture content and higher energy density demonstrated higher process efficiency compared to lignites with higher moisture content.
Article
Energy & Fuels
Magdalena Pankiewicz-Sperka, Krzysztof Kapusta, Wioleta Basa, Katarzyna Stolecka
Summary: The study focused on qualitative and quantitative characterization of UCG wastewater produced during four different experiments, showing significant relationships between wastewater composition and coal properties as well as gasification pressure, especially for organic pollutants like phenols, BTEX, and PAH's. The concentrations of these pollutants were found to vary depending on the type of coal and gasification pressure, with phenols having the highest concentrations. Additionally, the study found that concentrations of phenols, BTEX, and PAH's decrease with increasing pressure.
Review
Energy & Fuels
Jacek Borgulat, Katarzyna Ponikiewska, Lukasz Jalowiecki, Aleksandra Strugala-Wilczek, Grazyna Plaza
Summary: Underground coal gasification (UCG) is a clean coal technology, but it carries environmental risks. This review focuses on wetlands systems as a bioremediation method for treating UCG wastewater and provides examples and operating principles.
Article
Chemistry, Multidisciplinary
Xiaopeng Liu, Liangji Xu, Kun Zhang
Summary: Underground coal gasification (UCG) technology is a green, safe, and efficient method of coal development, playing a key role in the sustainable development of resources and energy. However, there is limited research on the strata movement and surface subsidence under high-temperature environments, hindering the further development of UCG technology. This study aims to address the key problems of UCG strata movement and surface subsidence prediction.
APPLIED SCIENCES-BASEL
(2023)
Article
Physics, Fluids & Plasmas
Satoru Kawaguchi, Noriyuki Nakata, Kazushi Satoh, Kazuhiro Takahashi, Kohki Satoh
Summary: The study measured various electron transport coefficients in nitrogen gas based on the arrival-time spectra of an electron swarm, successfully measuring the third-order transport coefficient for the first time. Additionally, the study demonstrated the importance of considering third-order and higher-order electron transport coefficients in order to properly determine the longitudinal diffusion coefficient at moderate and high reduced electric fields, which are traditionally ignored in electron swarm experiments.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Fluids & Plasmas
S. Kawaguchi, K. Takahashi, K. Satoh
Summary: A proposed electron collision cross section set for N-2 is calculated using Monte Carlo method with consideration of anisotropic inelastic electron scattering. The reliability of the set is verified by comparing calculated and measured electron transport coefficients. It is found that electron transport coefficients in N-2 are significantly influenced by anisotropic electron scattering as E/N values increase.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Construction & Building Technology
Peng Ma, Hideki Shimada, Takashi Sasaoka, Akihiro Hamanaka, Dyson N. Moses, Tumelo K. M. Dintwe, Fumihiko Matsumoto, Baosong Ma, Sheng Huang
Summary: This paper aims to investigate the pipe-soil interaction and improve the prediction accuracy of friction force in rectangular pipe-jacking. A new contact model for friction force prediction was proposed and verified through field data and numerical simulation.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Green & Sustainable Science & Technology
Pisith Mao, Hiroto Hashikawa, Takashi Sasaoka, Hideki Shimada, Zhijun Wan, Akihiro Hamanaka, Jiro Oya
Summary: This paper investigates the roof stability of a shallow depth longwall face under weak geological conditions. The results show that the canopy ratio, shield resistance force, and stress ratio have a significant impact on the roof conditions, and countermeasures such as reducing face-to-tip distance and cutting width can improve the stability of the longwall face.
Article
Chemistry, Multidisciplinary
Ulaankhuu Batsaikhan, Hiroto Hashikawa, Hideki Shimada, Takashi Sasaoka, Akihiro Hamanaka
Summary: This paper studies the applicability of pipe-jacking technology in underground coal mining through numerical analyses. The results show that using a precast concrete pipe can significantly improve geotechnical concerns and enhance the stability of the main gate.
APPLIED SCIENCES-BASEL
(2022)
Article
Energy & Fuels
Akihiro Hamanaka, Takashi Sasaoka, Hideki Shimada, Shinji Matsumoto
Summary: This paper discusses the use of fly ash for soil amelioration of acidic soils to promote plant growth. The results show that moderate addition of fly ash can improve plant growth, but the impact on metal ions leached from acidic soils needs to be considered.
INTERNATIONAL JOURNAL OF COAL SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Environmental
Dyson Moses, Hideki Shimada, Joan A. Onyango, Takashi Sasaoka, Akihiro Hamanaka
Summary: Carbonatites are generally competent rock masses, but they can be affected by weak features and in situ rock damage. Rock slope failure in such rocks is complex due to the presence of weak links. Numerical simulation shows that the presence of breccia in the rock mass can reduce slope stability, especially at gentler dipping angles. However, as the emplacement position of breccia moves away from the pit wall, stability performance increases at gentle dipping angles. Therefore, mine design in brecciated rock masses should consider the ratio between the distance of breccia from slope toe and pit depth to mitigate its impact.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Thermodynamics
Fa-qiang Su, Jun-bo Wu, Tao-Zhang, Qi-chao Deng, Yi-he Yu, Akihiro Hamanaka, Meng-Jia Dai, Jun-Nan Yang, Xiao-long He
Summary: In this study, the growth state of the combustion cavity during underground coal gasification (UCG) was investigated using simulation experiments and artificial coal seams. The results showed that the temperature and acoustic emission monitoring techniques can effectively infer the gasification combustion cavity.
Article
Energy & Fuels
Fa-qiang Su, Tao Zhang, Jun-bo Wu, Qi-chao Deng, Akihiro Hamanaka, Yi-he Yu, Meng-jia Dai, Xiao-long He, Jun-nan Yang
Summary: In this paper, UCG simulation experiments were conducted to investigate the effects of the gasification agent ratio on the composition and calorific value of the product gas. An energy recovery evaluation method and an evaluation model of the underground coal gasification temperature field were established. The results showed that increasing the oxygen concentration improved the calorific value of the produced gas and the energy recovery rate.
Article
Green & Sustainable Science & Technology
Hiroto Hashikawa, Pisith Mao, Takashi Sasaoka, Akihiro Hamanaka, Hideki Shimada, Ulaankhuu Batsaikhan, Jiro Oya
Summary: This study discusses the design of safety pillar width in longwall mining under weak geological conditions. It reveals that conventional equations for pillar width determination are suitable for maintaining the stability of the pillar itself but not for the stability of the longwall face. Increasing pillar width and setting load of the powered support can improve stability.
Article
Engineering, Geological
Cho Thae Oo, Dyson Moses, Takashi Sasaoka, Hideki Shimada, Akihiro Hamanaka, Joan A. Onyango, Ulaankhuu Batsaikhan, Seelae Phaisopha, Ian K. Tsuma
Summary: This study aims to develop optimal designs and guidelines for stable excavation of multiple inclined veins in weak rock mass conditions. The results suggest that developing stopes with width dimensions of <= 3 m and with certain intervals between parallel inclined veins is the most effective approach in weak rock mass conditions. The cut and fill method is found to be more suitable for multiple veins excavation compared to the open stoping method.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2023)
Article
Multidisciplinary Sciences
Akihiro Hamanaka, Yuma Ishii, Ken-ichi Itakura, Takashi Sasaoka, Hideki Shimada, Nuhindro Priagung Widodo, Budi Sulistianto, Jun-ichi Kodama, Gota Deguchi
Summary: Underground Coal Gasification (UCG) requires monitoring of the gasification area due to its invisible nature and high reaction temperatures. This research conducted coal heating and small-scale UCG experiments to examine the applicability of Acoustic Emission (AE) technique as a monitoring method during UCG. The results showed that AE monitoring is effective in estimating the gasification area, especially during coal gasification, as it helps capture fracturing events and expands with the high-temperature region.
SCIENTIFIC REPORTS
(2023)
Article
Construction & Building Technology
Bosong Yu, Hideki Shimada, Takashi Sasaoka, Akihiro Hamanaka, Fumihiko Matsumoto, Tomo Morita
Summary: This paper discusses a Japanese box-jacking project that is over 220 meters in length, focusing on the relationship between tunnelling parameters and jacking force. It introduces calculation approaches for forecasting jacking force during curved box-jacking, and compares the proposed approach to the current industry method. The results show that the proposed approach provides better forecasts of monitored field data, highlighting the importance of interpreting field data for assimilating box-jacking experience in different ground conditions.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2023)
Article
Mining & Mineral Processing
T. K. M. Dintwe, T. Sasaoka, H. Shimada, A. Hamanaka, D. Moses
Summary: This study investigates the suitability of underground mining sequences in the Zuuntsagaan mine and evaluates the effects on stope and open pit slope stability. The results show that the top-bottom sequence has lower ground movements compared to the bottom-up sequence, especially in the underground section.
JOURNAL OF MINING SCIENCE
(2022)
Article
Engineering, Geological
Peng Ma, Hideki Shimada, Takashi Sasaoka, Akihiro Hamanaka, Tumelo K. M. Dintwe, Donjiang Pan
Summary: This paper discusses the effectiveness of the pipe roof method in reducing ground settlement during underground space construction, with a focus on different pipe roof disposition schemes. The results show that the pipe roof method can reduce the impact of new buildings on the ground, with the L-shaped system being more effective when the distance between structures is less than or equal to half of the width of a box culvert.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2021)
Article
Energy & Fuels
Shitong Fang, Houfan Du, Tao Yan, Keyu Chen, Zhiyuan Li, Xiaoqing Ma, Zhihui Lai, Shengxi Zhou
Summary: This paper proposes a new type of nonlinear VIV energy harvester (ANVEH) that compensates for the decrease in peak energy output at low wind speeds by introducing an auxiliary structure. Theoretical and experimental results show that ANVEH performs better than traditional nonlinear VIV energy harvesters under various system parameter variations.
Article
Energy & Fuels
Wei Jiang, Shuo Zhang, Teng Wang, Yufei Zhang, Aimin Sha, Jingjing Xiao, Dongdong Yuan
Summary: A standardized method was developed to evaluate the availability of solar energy resources in road areas, which combined the Analytic Hierarchy Process (AHP) and the Geographic Information System (GIS). By analyzing critical factors and using a multi-indicator evaluation method, the method accurately evaluated the utilization of solar energy resources and guided the optimal location selection for road photovoltaic (PV) projects. The results provided guidance for the application of road PV projects and site selection for route corridors worldwide, promoting the integration of transportation and energy.
Article
Energy & Fuels
Chang Liu, Jacob A. Wrubel, Elliot Padgett, Guido Bender
Summary: The study investigates the effects of coating defects on the performance of the anode porous transport layer (PTL) in water electrolyzers. The results show that an increasing fraction of uncoated regions on the PTL leads to decreased cell performance, with continuous uncoated regions having a more severe impact compared to multiple thin uncoated strips.
Article
Energy & Fuels
Marcos Tostado-Veliz, Xiaolong Jin, Rohit Bhakar, Francisco Jurado
Summary: In this paper, a coordinated charging price mechanism for clusters of parking lots is proposed. The research shows that enabling vehicle-to-grid characteristics can bring significant economic benefits for users and the cluster coordinator, and vehicle-to-grid impacts noticeably on the risk-averse character of the uncertainty-aware strategies. The developed pricing mechanism can reduce the cost for users, avoiding to directly translate the energy cost to charging points.
Article
Energy & Fuels
Duan Kang
Summary: Building an energy superpower is a key strategy for China and a long-term goal for other countries. This study proposes an evaluation system and index for measuring energy superpower, and finds that China has significantly improved its ranking over the past 21 years, surpassing other countries.
Article
Energy & Fuels
Fucheng Deng, Yifei Wang, Xiaosen Li, Gang Li, Yi Wang, Bin Huang
Summary: This study investigated the synergistic blockage mechanism of sand and hydrate in gravel filling layer and the evolution of permeability in the layer. Experimental models and modified permeability models were established to analyze the effects of sand particles and hydrate formation on permeability. The study provided valuable insights for the safe and efficient exploitation of hydrate reservoirs.
Article
Energy & Fuels
Hao Wang, Xiwen Chen, Natan Vital, Edward Duffy, Abolfazl Razi
Summary: This study proposes a HVAC energy optimization model based on deep reinforcement learning algorithm. It achieves 37% energy savings and ensures thermal comfort for open office buildings. The model has a low complexity, uses a few controllable factors, and has a short training time with good generalizability.
Article
Energy & Fuels
Moyue Cong, Yongzhuo Gao, Weidong Wang, Long He, Xiwang Mao, Yi Long, Wei Dong
Summary: This study introduces a multi-strategy ultra-wideband energy harvesting device that achieves high power output without the need for external power input. By utilizing asymmetry, stagger array, magnetic coupling, and nonlinearity strategies, the device maintains a stable output voltage and high power density output at non-resonant frequencies. Temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the device.
Article
Energy & Fuels
Tianshu Dong, Xiudong Duan, Yuanyuan Huang, Danji Huang, Yingdong Luo, Ziyu Liu, Xiaomeng Ai, Jiakun Fang, Chaolong Song
Summary: Electrochemical water splitting is crucial for hydrogen production, and improving the hydrogen separation rate from the electrode is essential for enhancing water electrolyzer performance. However, issues such as air bubble adhesion to the electrode plate hinder the process. Therefore, a methodology to investigate the two-phase flow within the electrolyzer is in high demand. This study proposes using a microfluidic system as a simulator for the electrolyzer and optimizing the two-phase flow by manipulating the micro-structure of the flow.
Article
Energy & Fuels
Shuo Han, Yifan Yuan, Mengjiao He, Ziwen Zhao, Beibei Xu, Diyi Chen, Jakub Jurasz
Summary: Giving full play to the flexibility of hydropower and integrating more variable renewable energy is of great significance for accelerating the transformation of China's power energy system. This study proposes a novel day-ahead scheduling model that considers the flexibility limited by irregular vibration zones (VZs) and the probability of flexibility shortage in a hydropower-variable renewable energy hybrid generation system. The model is applied to a real hydropower station and effectively improves the flexibility supply capacity of hydropower, especially during heavy load demand in flood season.
Article
Energy & Fuels
Zhen Wang, Kangqi Fan, Shizhong Zhao, Shuxin Wu, Xuan Zhang, Kangjia Zhai, Zhiqi Li, Hua He
Summary: This study developed a high-performance rotary energy harvester (AI-REH) inspired by archery, which efficiently accumulates and releases ultralow-frequency vibration energy. By utilizing a magnetic coupling strategy and an accumulator spring, the AI-REH achieves significantly accelerated rotor speeds and enhanced electric outputs.
Article
Energy & Fuels
Yi Yang, Qianyi Xing, Kang Wang, Caihong Li, Jianzhou Wang, Xiaojia Huang
Summary: In this study, a novel hybrid Quantile Regression (QR) model is proposed for Probabilistic Load Forecasting (PLF). The model integrates causal dilated convolution, residual connection, and Bidirectional Long Short-Term Memory (BiLSTM) for multi-scale feature extraction. In addition, a Combined Probabilistic Load Forecasting System (CPLFS) is proposed to overcome the inherent flaws of relying on a single model. Simulation results show that the hybrid QR outperforms traditional models and CPLFS exceeds the best benchmarks in terms of prediction accuracy and stability.
Article
Energy & Fuels
Wen-Jiang Zou, Young-Bae Kim, Seunghun Jung
Summary: This paper proposes a dynamic prediction model for capacity fade in vanadium redox flow batteries (VRFBs). The model accurately predicts changes in electrolyte volume and capacity fade, enhancing the competitiveness of VRFBs in energy storage applications.
Article
Energy & Fuels
Yuechao Ma, Shengtie Wang, Guangchen Liu, Guizhen Tian, Jianwei Zhang, Ruiming Liu
Summary: This paper focuses on the balance of state of charge (SOC) among multiple battery energy storage units (MBESUs) and bus voltage balance in an islanded bipolar DC microgrid. A SOC automatic balancing strategy is proposed considering the energy flow relationship and utilizing the adaptive virtual resistance algorithm. The simulation results demonstrate the effectiveness of the proposed strategy in achieving SOC balancing and decreasing bus voltage unbalance.
Article
Energy & Fuels
Raad Z. Homod, Basil Sh. Munahi, Hayder Ibrahim Mohammed, Musatafa Abbas Abbood Albadr, Aissa Abderrahmane, Jasim M. Mahdi, Mohamed Bechir Ben Hamida, Bilal Naji Alhasnawi, A. S. Albahri, Hussein Togun, Umar F. Alqsair, Zaher Mundher Yaseen
Summary: In this study, the control problem of the multiple-boiler system (MBS) is formulated as a dynamic Markov decision process and a deep clustering reinforcement learning approach is applied to obtain the optimal control policy. The proposed strategy, based on bang-bang action, shows superior response and achieves more than 32% energy saving compared to conventional fixed parameter controllers under dynamic indoor/outdoor actual conditions.