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
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
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
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
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
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
Chemistry, Physical
Huan Liu, Shuqin Liu
Summary: This study compares energy consumption and greenhouse gas emissions between underground coal gasification (UCG)-based hydrogen production (UCG-H-2) and surface coal gasification (SCG)-based hydrogen production (SCG-H-2) using life cycle assessment. Results show UCG-H-2 has significant energy saving advantage, and 80% capture rate can achieve a balance between energy consumption and emissions. Scenario analysis suggests UCG substitution for hydrogen production can reduce energy consumption significantly.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Public, Environmental & Occupational Health
Reza Lotfian, Mehdi Najafi
Article
Environmental Sciences
Hadi Parmar, Alireza Yarahmadi Bafghi, Mehdi Najafi
ENVIRONMENTAL EARTH SCIENCES
(2019)
Article
Construction & Building Technology
Mohammad Sina Abdollahi, Mehdi Najafi, Alireza Yarahmadi Bafghi, Mohammad Fatehi Marji
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2019)
Article
Energy & Fuels
Ramin Rafiee, Azita Azarfar, Mehdi Najafi, Seyed Mohammad Esmaeil Jalali
ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
(2020)
Article
Environmental Sciences
Khadijeh Amani, Mehdi Najafi, Ramin Rafiee
Summary: The sudden outburst of coal and gas is a complex and dynamic incident in underground coal mines. This study proposes a novel method to predict the possibility of gas outburst in coal seams by considering ten main variables and using a fuzzy interaction matrix. The proposed method aims to reduce the risks of coal and gas outburst in coal mines.
ENVIRONMENTAL EARTH SCIENCES
(2021)
Article
Engineering, Multidisciplinary
Amir Jafarpour, Mehdi Najafi
Summary: Geological studies are crucial in mining activities. This study presents a fuzzy hybrid approach for evaluating and classifying coal seams for methane drainage. The proposed approach provides a logical tool for selecting suitable coal seams for methane drainage operation, reducing the risk of methane drainage projects in underground coal mines.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2022)
Article
Mining & Mineral Processing
Ali Hosseini, Mehdi Najafi, Amin Hossein Morshedy
Summary: A large amount of gas is emitted during underground mining, which poses safety risks and decreases productivity. Efficient methane drainage is crucial for safety and productivity improvement. The cross-measure borehole method is commonly used for methane drainage. This study determined the suitable distance between methane drainage stations using measurement data, and found that distances in the range of 9-12 m achieved the highest methane drainage efficiency.
JOURNAL OF MINING INSTITUTE
(2022)
Article
Geosciences, Multidisciplinary
Ali Hosseini, Mehdi Najafi
Summary: Rock mass methane drainage is an efficient approach to control methane hazards in underground coal mining, preventing and reducing methane emissions, outflows, and sudden outbursts. Experimental equations were used to calculate the methane drainage zone in the E-4 panel of the Tabas coal mine and determine the drainage borehole pattern.
RUDARSKO-GEOLOSKO-NAFTNI ZBORNIK
(2021)
Article
Engineering, Geological
Mohammad hossein Motamedi, Mehdi Najafi
Summary: Underground mining operations require support systems or ore pillars to maintain stability, with designing optimal pillar dimensions being a crucial factor. Through numerical simulation, it was found that in the Faryab mine, grouting technology can reduce the pillar dimensions and enhance the stability by strengthening the rock properties.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2021)
Article
Mining & Mineral Processing
M. Damghani, R. Rahmannejad, M. Najafi
JOURNAL OF MINING SCIENCE
(2019)
Article
Geosciences, Multidisciplinary
Mehdi Najafi, Ramin Rafiee
RUDARSKO-GEOLOSKO-NAFTNI ZBORNIK
(2019)
Article
Mining & Mineral Processing
M. Noroozi, R. Rafiee, M. Najafi
JOURNAL OF MINING AND ENVIRONMENT
(2018)
Article
Energy & Fuels
Amin Jowkar, Farhang Sereshki, Mehdi Najafi
INTERNATIONAL JOURNAL OF COAL SCIENCE & TECHNOLOGY
(2020)