The analysis of the underground coal gasification in experimental equipment

Laciak, Marek; Kostúr, Karol; Durdán, Milan; Kačur, Ján; Flegner, Patrik

doi:10.1016/j.energy.2016.08.004

Cited by 52 publications

(26 citation statements)

References 15 publications

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“…The average compositions of H 2 , CO, and CH 4 obtained were 10.1%, 9.6%, and 6.8%, respectively. The average gas calorific value (123.2 kJ/mol) obtained in this movable injection point method is higher than obtained using the shaft method (84.9 kJ/mol) by Wiatowski et al Further, Laciak et al used coals of 26% ash content, which is similar to the property of coal in the current study (25% ash), and reported a syngas with 92.3 kJ/mol during the oxygen gasification stage, whereas it was found higher as 123.2 kJ/mol by movable injection point method.…”

Section: Resultssupporting

confidence: 58%

“…This is slightly higher than the heating value of syngas, which was obtained during the single point injection method. Laciak et al 11 and Kostur et al 19 reported 73 and 63.9 kJ/mol of the heating value of syngas during air gasification, respectively. Hence, the movable injection point for air gasification gains a marginal increase in the chemical energy of syngas.…”

Section: High Ash Coal Gasification Using Air (Exp#3)mentioning

confidence: 98%

“…Duan et al developed a model for CO 2 ‐O 2 dual‐stage–based gasification. Laciak et al executed UCG experiments with air as the primary gasifying agent and oxygen for a shorter duration of time. The average heating value of the syngas obtained was 77 kJ/mol during air gasification and 116 kJ/mol during pure oxygen gasification.…”

Section: Introductionmentioning

confidence: 99%

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Movable injection point–based syngas production in the context of underground coal gasification

Kashyap

Vairakannu

2020

Int J Energy Res

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Summary Underground coal gasification (UCG) has been proven as a viable technology for the generation of high calorific value syngas using deep mine coal seams. The use of multiple injection points/movable injection point method could be an alternate technique for efficient gasification of high ash Indian coals. In this context, the present study is focused on evaluating the heating value of syngas using a variety of gasifying agents such as pure O2, air, humidified O2, and CO2‐O2 dual‐stage gasification under movable injection method for high ash coals. It is found that the use of movable injection point method had significantly increased the heating value of the product gas, compared with the fixed point injection method. For high and low ash coal under pure O2 gasification, the calorific value of syngas obtained using movable injection point is 123.2 and 153.9 kJ/mol, which are 33.5% and 24.3% higher than the syngas calorific value obtained using fixed injection point, respectively. Further, the air as a gasification agent for high ash coals had increased the gross calorific value of the syngas by 24%, using this technology. The results of high ash coal gasification using humidified oxygen at optimum conditions (0.027‐kg moisture/kg dry O2) and CO2‐O2 gas had enhanced the syngas calorific value by 12.6% and 5%, respectively. Humidified O2 and CO2‐O2 gasifying agents produced a high‐quality syngas with the calorific value of 190 kJ/mol, among the gasifying agents used. The experimental results had shown that the movable injection point method is found to be a better alternative for the generation of calorific value‐enriched syngas using high ash‐based Indian coals.

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Section: Resultssupporting

confidence: 58%

Section: High Ash Coal Gasification Using Air (Exp#3)mentioning

confidence: 98%

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Movable injection point–based syngas production in the context of underground coal gasification

Kashyap

Vairakannu

2020

Int J Energy Res

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“…Note that the formation of methane due to the pyrolysis of coal (in the absence of oxygen), as observed previously [21][22][23][24], can considerably increase the heating value of the UCG product. However, since the produced gas from the coal pyrolysis is in contact with the injected oxygen from the rubble zone, it is instantly converted to CO 2 and H 2 O (see Fig.…”

Section: The Model For Deep Thin Coal Gasificationsupporting

confidence: 56%

Energy and exergy analysis of alternating injection of oxygen and steam in the low emission underground gasification of deep thin coal

et al. 2017

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• We model UCG process with alternating injection of steam/oxygen.• We used exergy analysis to investigate the practicality of the process.• We show that the alternating injection UCG is practical at low pressure.• Zero emission conversion of coal is not currently practical.• Co-injection of steam/oxygen results in a higher recovery of coal. A R T I C L E I N F O Keywords:Underground coal gasification Alternating injection Exergy analysis Carbon capture and storage A B S T R A C TRecent studies have shown that by coupling the underground coal gasification (UCG) with the carbon capture and storage (CCS), the coal energy can be economically extracted with a low carbon footprint. To investigate the effect of UCG and CCS process parameters on the feasibility of the UCG-CCS process, we utilize a validated mathematical model, previously published by the same authors, that can predict the composition of the UCG product, temperature profile, and coal conversion rate for alternating injection of air and steam for unmineable deep thin coal layers. We use the results of the model to conduct an energy and exergy analysis of the UCG process. We study the effect of various process parameters on the efficiency of the UCG process, the zeroemission recovery factor of coal, and the total CO 2 emission of the process. Moreover, we compare the alternating injection of air/steam with the injection of an air and steam mixture.Exergy analysis shows that the alternating injection of air/steam describes a practical process for UCG at low pressure. However, injecting a mixture of steam and oxygen results in a practical recovery factor of coal higher than the alternating injection process. Additionally, we show that the zero-emission conversion of unmineable deep thin coal resources in a coupled UCG-CCS process, that is not practical with the current state of technology, can be realized by increasing the energy efficiency of the carbon dioxide capture process.

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“…The UCG process is difficult to control in the subsurface. Hence, much effort has been invested into feasibility assessments and technology development by high-pressure experimental testing to increase its efficiency and stability (e.g., [52,[55][56][57]). Wiatowski et al [52] conducted experimental simulations of UCG, using large bulk samples of two lignites in an ex situ laboratory installation.…”

Section: Model Validation Against Ucg Experimental Datamentioning

confidence: 99%

Synthesis Gas Composition Prediction for Underground Coal Gasification Using a Thermochemical Equilibrium Modeling Approach

Otto

Kempka

2020

Energies

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Underground coal gasification (UCG) is an in situ conversion technique that enables the production of high-calorific synthesis gas from resources that are economically not minable by conventional methods. A broad range of end-use options is available for the synthesis gas, including fuels and chemical feedstock production. Furthermore, UCG also offers a high potential for integration with Carbon Capture and Storage (CCS) to mitigate greenhouse gas emissions. In the present study, a stoichiometric equilibrium model, based on minimization of the Gibbs function has been used to estimate the equilibrium composition of the synthesis gas. Thereto, we further developed and applied a proven thermodynamic equilibrium model to simulate the relevant thermochemical coal conversion processes (pyrolysis and gasification). Our modeling approach has been validated against thermodynamic models, laboratory gasification experiments and UCG field trial data reported in the literature. The synthesis gas compositions have been found to be in good agreement under a wide range of different operating conditions. Consequently, the presented modeling approach enables an efficient quantification of synthesis gas quality resulting from UCG, considering varying coal and oxidizer compositions at deposit-specific pressures and temperatures.

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The analysis of the underground coal gasification in experimental equipment

Cited by 52 publications

References 15 publications

Movable injection point–based syngas production in the context of underground coal gasification

Movable injection point–based syngas production in the context of underground coal gasification

Energy and exergy analysis of alternating injection of oxygen and steam in the low emission underground gasification of deep thin coal

Synthesis Gas Composition Prediction for Underground Coal Gasification Using a Thermochemical Equilibrium Modeling Approach

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