Best Practices in Underground Coal Gasification

Burton, Elizabeth A.; Upadhye, R.S.; Friedmann, S. Julio

doi:10.2172/1580018

Cited by 47 publications

(89 citation statements)

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“…UCG may provide a convenient source of energy from coal seams for which traditional coal extraction techniques are economically, technically or environmentally infeasible. Many studies have shown the potential advantages of UCG over the conventional mining methods, such as the increase in coal utilization efficiency and the improvement of economic performance with simultaneous minimization of environmental emissions [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Large-scale Experimental Investigations to Evaluate the Feasibility of Producing Methane-Rich Gas (SNG) through Underground Coal Gasification Process. Effect of Coal Rank and Gasification Pressure

et al. 2020

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An experimental campaign on the methane-oriented underground coal gasification (UCG) process was carried out in a large-scale laboratory installation. Two different types of coal were used for the oxygen/steam blown experiments, i.e., “Six Feet” semi-anthracite (Wales) and “Wesoła” hard coal (Poland). Four multi-day gasification tests (96 h continuous processes) were conducted in artificially created coal seams under two distinct pressure regimes-20 and 40 bar. The experiments demonstrated that the methane yields are significantly dependent on both the properties of coal (coal rank) and the pressure regime. The average CH4 concentration for “Six Feet” semi-anthracite was 15.8%vol. at 20 bar and 19.1%vol. at 40 bar. During the gasification of “Wesoła” coal, the methane concentrations were 10.9%vol. and 14.8%vol. at 20 and 40 bar, respectively. The “Six Feet” coal gasification was characterized by much higher energy efficiency than gasification of the “Wesoła” coal and for both tested coals, the efficiency increased with gasification pressure. The maximum energy efficiency of 71.6% was obtained for “Six Feet” coal at 40 bar. A positive effect of the increase in gasification pressure on the stabilization of the quantitative parameters of UCG gas was demonstrated.

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Section: Introductionmentioning

confidence: 99%

Large-scale Experimental Investigations to Evaluate the Feasibility of Producing Methane-Rich Gas (SNG) through Underground Coal Gasification Process. Effect of Coal Rank and Gasification Pressure

et al. 2020

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“…During UCG, temperatures of more than to 1500 • C can be reached in the UCG reactor and its close vicinity [43]. Thereby, pyrolysis reactions occur at a specific temperature range (350-900 • C) [4], followed by a number of competing intermediate reactions including both, heterogeneous reactions between gas and char and homogeneous gas phase reactions [25].…”

Section: Methodsmentioning

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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“…In view of CO 2 storage, one approach discussed by Burton et al [47] and Kempka et al [25] was to reinject captured CO 2 into the abandoned UCG reactors. However, we assumed the availability of a geological storage reservoir with sufficient capacity to completely trap the captured CO 2 of up to 42 Mt during a 20-year operational lifetime.…”

Section: Capex Valuementioning

confidence: 99%

Techno-Economic Comparison of Onshore and Offshore Underground Coal Gasification End-Product Competitiveness

Nakaten

Kempka

2019

Energies

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Underground coal gasification (UCG) enables utilization of coal reserves, currently not economically exploitable due to complex geological boundary conditions. Hereby, UCG produces a high-calorific synthesis gas that can be used for generation of electricity, fuels, and chemical feedstock. The present study aims to identify economically-competitive, site-specific end-use options for onshore- and offshore-produced UCG synthesis gas, taking into account the capture and storage (CCS) and/or utilization (CCU) of produced CO 2 . Modeling results show that boundary conditions favoring electricity, methanol, and ammonia production expose low costs for air separation, low compression power requirements, and appropriate shares of H 2 /N 2 . Hereby, a gasification agent ratio of more than 30% oxygen by volume is not favorable from the economic and CO 2 mitigation viewpoints. Compared to the costs of an offshore platform with its technical equipment, offshore drilling costs are marginal. Thus, uncertainties related to parameters influenced by drilling costs are negligible. In summary, techno-economic process modeling results reveal that air-blown gasification scenarios are the most cost-effective ones, while offshore UCG-CCS/CCU scenarios are up to 1.7 times more expensive than the related onshore processes. Hereby, all investigated onshore scenarios except from ammonia production under the assumed worst-case conditions are competitive on the European market.

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Best Practices in Underground Coal Gasification

Cited by 47 publications

References 0 publications

Large-scale Experimental Investigations to Evaluate the Feasibility of Producing Methane-Rich Gas (SNG) through Underground Coal Gasification Process. Effect of Coal Rank and Gasification Pressure

Large-scale Experimental Investigations to Evaluate the Feasibility of Producing Methane-Rich Gas (SNG) through Underground Coal Gasification Process. Effect of Coal Rank and Gasification Pressure

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

Techno-Economic Comparison of Onshore and Offshore Underground Coal Gasification End-Product Competitiveness

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