Flame propagation in a gasification channel

Saulov, D. N.; Plumb, O. A.; Klimenko, A. Y.

doi:10.1016/j.energy.2009.11.006

Cited by 20 publications

(9 citation statements)

References 26 publications

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“…Modeling the development of gas fingering requires detailed knowledge on a potential spatial distribution of the coal's dual porosity and permeability characteristics to consider the coal cleat system and potential fractures in addition to the coal matrix in our non-isothermal multiphase flow simulations. Furthermore, phase transitions occur abruptly, effectively representing a jump from fully liquid-to gas-saturated grid elements, which is in good agreement with existing publications on evaporation front movements in porous media [29,64]. A comparison of isothermal simulations without any phase transition with non-isothermal ones with phase transitions shows that neglecting non-isothermal effects results in deviations in the calculated spatial flow regimes and water balances.…”

Section: Discussionsupporting

confidence: 73%

“…As a result, a layer of steam surrounds the UCG reactor, termed the steam jacket. In order to prevent or significantly mitigate potential environmental impacts, UCG reactors are generally operated below hydrostatic pressure, hindering the outflow of UCG process fluids into adjacent aquifers [28,29]. Although, the difference between reactor and hydrostatic pressure produces an inflow of groundwater into the reactor, preventing UCG by-product leakage, on the other hand, the emerging steam jacket reduces the heat consumption by water evaporation and controls the spatial water inflow into the reactor, allowing operators to maintain an efficient and sustainable operation [1,30,31].…”

Section: Introductionmentioning

confidence: 99%

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Prediction of Steam Jacket Dynamics and Water Balances in Underground Coal Gasification

Otto

Kempka

2017

Energies

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Underground coal gasification (UCG) converts coal to a high-calorific synthesis gas for the production of fuels or chemical feedstock. UCG reactors are generally operated below hydrostatic pressure to avoid leakage of UCG fluids into overburden aquifers. Additionally, fluid flow out of and into the reactor is also determined by the presence of the steam jacket, emerging in close reactor vicinity due to the high temperatures generated in UCG operation. Aiming at improving the understanding of the substantial role of the steam jacket in UCG operations, we employ numerical non-isothermal multiphase flow simulations to assess the occurring multiphase fluid flow processes. For that purpose, we first validate our modeling approach against published data on the U.S. UCG field trials at Hanna and Hoe Creek, achieving a very good agreement between our simulation and the observed water balances. Then, we discuss the effect of coal seam permeability and UCG reactor pressure on the dynamic multiphase flow processes in the reactor's vicinity. The presented modeling approach allows for the quantification and prediction of time-dependent temperature and pressure distributions in the reactor vicinity, and thus steam jacket dynamics as well as reactor water inand outflows.

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Section: Discussionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Prediction of Steam Jacket Dynamics and Water Balances in Underground Coal Gasification

Otto

Kempka

2017

Energies

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“…Under such conditions the flow in the Figure 35. Dependence of burn velocity on the air flow rate [72]: (a) experimental data from Skafa [20], and (b) calculated data from Saulov et al [72].…”

Section: Energies 2015 8 38mentioning

confidence: 99%

“…In the case of very hot and diffusion-controlled flame, Saulov et al [72] considered the limit of high temperatures, a high activation energy, and a strong air flow. Under these conditions the surface of the channel is considered to have two zones, cold and hot.…”

Section: Energies 2015 8 38mentioning

confidence: 99%

“…Considering the importance of the flame front propagation in the gasification channel for viable operations in UCG, Saulov et al [72] developed a simplified physical model to describe the primary features of the flame behaviour in a long channel through a coal block. According to their model, a number of factors, such as air flow rate, flame temperature, oxidizer diffusion rate, and radiative heat transport, etc., are the decisive factors to determine if the flame tends to propagate toward the injection point (reverse combustion) or the downstream direction (forward combustion).…”

Section: Energies 2015 8 38mentioning

confidence: 99%

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Modelling Underground Coal Gasification—A Review

et al. 2015

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Abstract:The technical feasibility of underground coal gasification (UCG) has been established through many field trials and laboratory-scale experiments over the past decades. However, the UCG is site specific and the commercialization of UCG is being hindered due to the lack of complete information for a specific site of operation. Since conducting UCG trials and data extraction are costly and difficult, modeling has been an important part of UCG study to predict the effect of various physical and operating parameters on the performance of the process. Over the years, various models have been developed in order to improve the understanding of the UCG process. This article reviews the approaches, key concepts, assumptions, and limitations of various forward gasification UCG models for cavity growth and product gas recovery. However, emphasis is given to the most important models, such as packed bed models, the channel model, and the coal slab model. In addition, because of the integral part of the main models, various sub-models such as drying and pyrolysis are also included in this review. The aim of this study is to provide an overview of the various simulation methodologies and sub-models in order to enhance the understanding of the critical aspects of the UCG process.

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Laboratory investigation into fractal characteristics of methane explosion flame

et al. 2014

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This article presents the results of an experimental study which aims to examine flame propagation pattern occurring during methane explosion under different gas concentrations. Five methane-to-air volume concentration ratios are tested, namely 8, 9.5, 9.7, 10, and 11%. Flame images are captured with high-speed camera and examined with fractal analysis of triple-prismatic surface area. The experimental results suggest that the closer the methane concentration is to the optimal equivalence ratio, the greater the maximum fractal dimension of the explosion. It is shown that the maximum fractal dimension occurs at a methane concentration of 9.5% when the methane concentration moves closer to the optimal equivalence ratio and the explosion is most intense. The fractal dimension and its rate of change serve directly as indicators of the explosion intensity, the gradient of intensity, and the propagation pattern of the entire flame. These results shed light on the dynamic characteristics of flame propagation occurring in methane explosion.

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Flame propagation in a gasification channel

Cited by 20 publications

References 26 publications

Prediction of Steam Jacket Dynamics and Water Balances in Underground Coal Gasification

Prediction of Steam Jacket Dynamics and Water Balances in Underground Coal Gasification

Modelling Underground Coal Gasification—A Review

Laboratory investigation into fractal characteristics of methane explosion flame

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