Laboratory investigation on underground coal gasification technique with real-time analysis

Mandal, Rajasi; Maity, Tanmoy; Chaulya, S.K.; Prasad, G.M.

doi:10.1016/j.fuel.2020.117865

Cited by 13 publications

(10 citation statements)

References 18 publications

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“…A good agreement was shown between the calculated and the experimental data at every stage. A laboratory-based UCG model with advanced real-time control and monitoring was used for monitoring cavity formation, temperatures, syngas characteristics, and coal-tar [12]. Results showed the ability of the laboratory-based UCG process to forecast the sustainability and standardization before the UCG process implementation by observed of the realized experiment.…”

Section: Introductionmentioning

confidence: 99%

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Durdán¹,

Benková²,

Laciak³

et al. 2021

Energies

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The underground coal gasification represents a technology capable of obtaining synthetic coal gas from hard-reached coal deposits and coal beds with tectonic faults. This technology is also less expensive than conventional coal mining. The cavity is formed in the coal seam by converting coal to synthetic gas during the underground coal gasification process. The cavity growth rate and the gasification queue’s moving velocity are affected by controllable variables, i.e., the operation pressure, the gasification agent, and the laboratory coal seam geometry. These variables can be continuously measured by standard measuring devices and techniques as opposed to the underground temperature. This paper researches the possibility of the regression models utilization for temperature data prediction for this reason. Several regression models were proposed that were differed in their structures, i.e., the number and type of selected controllable variables as independent variables. The goal was to find such a regression model structure, where the underground temperature is predicted with the greatest possible accuracy. The regression model structures’ proposal was realized on data obtained from two laboratory measurements realized in the ex situ reactor. The obtained temperature data can be used for visualization of the cavity growth in the gasified coal seam.

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Section: Introductionmentioning

confidence: 99%

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Durdán¹,

Benková²,

Laciak³

et al. 2021

Energies

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“…To solve these problems, changes in the traditional methods of coal production and consumption must be made without delay. Underground coal gasification has provided an important research topic as the cutting-edge technology for clean coal mining (Jiang et al 2020, Mandal et al 2020, Liu and Liu 2021, Feng et al 2021, Rnm and Pkg 2021, Hu et al 2021, Huang et al 2021). Pyrolysis is the basis of other chemical processes, such as coal gasification, and is the first step in the clean utilization of coal.…”

Section: Introductionmentioning

confidence: 99%

Pyrolysis characteristics and microstructure evolution of different coal types

Chen

Yin

Sun

et al. 2022

Energy Exploration & Exploitation

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Coal pyrolysis is the basis of coal gasification, as it is the necessary reaction step in the coal conversion process. To study the pyrolysis characteristics of different coal grades under temperature, thermal simulation tests of three different ranks of coal were conducted, and the pore structure and gas products were analyzed by using liquid nitrogen adsorption and gas chromatographic, and perform fractal fitting for pores of different size. The results show that the pyrolysis gas output of Inner Mongolia lignite is higher than that of Xinjiang long flame coal and Hancheng bituminous coal. With the increase of coal rank, the gas output of each gas component also shows a decreasing trend and the initial temperature and peak temperature of various gases gradually shift to high temperature. With the increase of temperature, the average pore size, volume, specific surface area, and fractal dimension of the three kinds of coal char show an increasing trend. The average pore size and pore volume of coal char increase, and the fractal dimension increase with the increase of coal rank. The comprehensive comparative analysis of the gaseous products, average pore size, pore volume, and fractal dimension of the three coal chars shows that Inner Mongolia lignite has high gas production, large average pore size, good connectivity, and simple pore structure, which is conducive to the escape of pyrolysis gas and the transportation of gasification agent and is the best favorable coal for gasification. The research results are expected to provide experimental guidance for the actual production of underground coal gasification.

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“…The actual reaction conditions of UCG can be indirectly reflected by studying the mineralogical changes. Some researchers have investigated the actual UCG reaction conditions according to the observed mineralogical transformations 15 . However, from the technical and economic point of view, it is difficult and costly to directly collect ash and slag by drilling holes and then study the mineral characteristics of ash and slag under various gasification process conditions.…”

Section: Introductionmentioning

confidence: 99%

Sequential transformation study of minerals during underground coal gasification: Promising to indirectly reflect the actual reaction condition

Wang

et al. 2021

Asia-Pacific J Chem Eng

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The mineralogical characteristics of underground coal gasification (UCG) residuals are closely related to the gasification conditions. The study of the mineral composition and transformation of ash and slag under different gasification conditions has important scientific significance for understanding the real gasification conditions, improving the utilization efficiency of coal, and identifying and controlling the environmental impact. In this paper, the sequential transformation of minerals under different temperature and atmosphere are studied by X‐ray diffraction (XRD) and FactSage software, and the elemental composition of the surface of the UCG ash and slag is characterized by SEM‐EDX. The results show that the main minerals in the semicoke are quartz (SiO2), illite (K1.5Al4(Si6.5Al1.5)O20(OH)4), and sanidine (KAlSi3O8). In the 900–1300°C reduction, ash, quartz, sanidine, hercynite (FeAl2O4), anorthite (CaAl2Si2O8), and mullite (Al6Si2O13) are the main minerals. The minerals in the oxidation residuals (1100–1500°C) are quartz, anorthite, hematite (Fe2O3), hercynite, cordierite (Fe2Al4Si5O18), and cristobalite. The reaction temperature has a significant effect on the changes in mineralogy. The reaction temperature is low during the pyrolysis process, and most changes involve only structural changes. With the reaction temperature increases, a series of reactions occur between different minerals. The reaction atmosphere also has a significant effect on the mineralogy. The research on the transformation of minerals in UCG residues can indirectly reflect the actual process of UCG, which can provide suggestions for the stable operation of the UCG process.

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Laboratory investigation on underground coal gasification technique with real-time analysis

Cited by 13 publications

References 18 publications

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Pyrolysis characteristics and microstructure evolution of different coal types

Sequential transformation study of minerals during underground coal gasification: Promising to indirectly reflect the actual reaction condition

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