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Introduction
Published in Vivek Ranade, Sanjay Mahajani, Ganesh Samdani, Computational Modeling of Underground Coal Gasification, 2019
Vivek Ranade, Sanjay Mahajani, Ganesh Samdani
Energy touches the lives of everyone, every day. Global demand for energy has increased enormously since the advent of rapid industrialization, and this is especially true for growing economies like India. Coal supplies almost a third of all the energy used worldwide and makes up 40% of electricity generation. Despite legitimate concerns about pollution and greenhouse-gas emissions caused by coal, it will continue to play a significant role in energy scenarios for a foreseeable future. Significant efforts are being made by governments and industry to develop and to implement more efficient technologies to ensure that coal becomes a cleaner source of energy in the decades to come. Underground coal gasification (UCG) is one such technology which has a potential not just to make coal as a cleaner energy resource but also to harness otherwise un-mineable coal.
Fossil Fuels
Published in Efstathios E. Michaelides, Energy, the Environment, and Sustainability, 2018
Underground coal gasification (UCG) is an environmentally friendly method to produce syngas without extracting the coal from its underground seams. Moist air is supplied to the underground coal, and ignition is initiated. The heat produced by the partial combustion of air increases the underground temperature to produce in situ syngas at high pressure, which is removed by gas wells. The syngas produced is free of most of the pollutants associated with coal and may be directly utilized in a power plant. Although this method has been known since the nineteenth century, there are not many UCG plants, primarily because the underground partial combustion of coal and the overall gasification process are not as efficient as the better controlled overground gasification processes.
The influence of the roof and floor geological structures on the ash composition produced from coal at UCG temperatures
Published in International Journal of Coal Preparation and Utilization, 2020
R.C. Uwaoma, C.A. Strydom, R.H. Matjie, J.R. Bunt, J.C van Dyk
Underground coal gasification (UCG) is considered to be one of the technologies that are economically viable and assists in facilitating the recovering of energy from coal reserves that are too deep or too thin to mine by conventional surface or strip-mining techniques (Edgar et al. 1981; Gregg and Edgar 1978; Kapusta and Stańczyk 2011). South Africa has been using surface gasification for coal to liquid technology (CTL) since 1955 (Van Nierop, Erasmus, and van Zyl 2000), UCG technology offers a wide range of economic, environmental and technical benefits, but has the potential to create groundwater contamination, uncontrollable cavity growth, underground fires and subsidence if the process is not properly managed (Kapusta and Stańczyk 2011; Khadse et al. 2007; Liu et al. 2007; Verma et al. 2014).
Effects of the Steam-To-Oxygen Ratio and the Equivalence Ratio on Underground Coal Gasification
Published in Combustion Science and Technology, 2023
Huijun Fang, Sen Li, Tengze Ge, Yinan Liu, Yueyu Yu, Yuewu Liu, Danlu Liu, Jiuge Ding, LongLong Li
Underground coal gasification (UCG) is a process of converting coal to combustible gas at the site of the underground coal seam. Since UCG reduces the environmental pollution during coal mining and utilization (Perkins 2018; Zou et al. 2012), it is considered as a disruptive technology for carbon neutrality goals (Zou et al. 2012). However, the production process of deep underground coal gasification is invisible, and the measurement and control is difficult. The operating parameters of underground coal gasification directly affect the production safety and efficiency.
Numerical simulation of solid-fluid-thermal coupling in the heating stage of in-situ injection of supercritical water for hydrogen production from coal
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Zixiang Zhang, Yangsheng Zhao, Zijun Feng
Underground Coal Gasification (UCG) is an economically and environmentally sustainable clean coal technology that converts coal in-situ to a combustible gas. It involves several complex physicochemical processes, such as drying, evaporation, thermal expansion, pyrolysis, compression and contraction, gasification, and combustion (Jiang, Chen, and Farouq Ali 2020; Su et al. 2022). Research is currently conducted in several coal-rich countries; however, China is the frontrunner in both industrial-scale UCG pilots and laboratory experiments (Jiang et al. 2022). Yin et al. (Yin et al. 2023) explored the hydrogen production of different coals in underground coal gasification. Stańczyk and Krzysztof (Stańczyk et al. 2010, 2012) demonstrated the feasibility of the gasification of lignite to a hydrogen-rich gas under subsurface conditions simulated by an ex-situ reactor. They maintained the original subsurface coal gasification conditions for experiments and analyzed parameters, such as average gas production and hydrogen content. Liangliang Jiang (Jiang, Chen, and Ali 2017) explored the effect of the reverse combustion theory on UCG in porous media via modeling and determined the conditions to successfully implement a reverse combustion connection. Jiang (Jiang et al. 2022, 2023; Jiang, Chen, and Farouq Ali 2019) also constructed a three-dimensional post-combustion UCG cavity model to simulate the migration of in a supercritical state and determined the feasibility of injecting to the UCG cavity for storage. Li, Xuelong (Li et al. 2023; Zhang et al. 2023, 2023) established a mechanical model of the coal wall and used the deflection theory of material mechanics to find the maximum point at which the coal wall is most likely to deform and break during mining.