Mathematical modeling of combustion and gasification of a wet coal slab—II

Massaquoi, J.G.M.; Riggs, James B.

doi:10.1016/0009-2509(83)85032-5

Cited by 18 publications

(4 citation statements)

References 4 publications

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“…A higher operating pressure can positively affect the concentration of methane and hydrogen, ultimately affecting the syngas's calorific value [57]. Existing numerical models considered UCG up to a pressure of 0.5 MPa [58][59][60][61]. Recently, a UCG test was conducted in Alberta (Canada) with an operating pressure of up to 12 MPa.…”

Section: High-pressure Coal Gasificationmentioning

confidence: 99%

Investigation of Underground Coal Gasification in Laboratory Conditions: A Review of Recent Research

Kačur,

Laciak,

Durdán

et al. 2023

Energies

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The underground coal gasification (UCG) technology converts coal into product gas and provides the option of environmentally and economically attractive coal mining. Obtained syngas can be used for heating, electricity, or chemical production. Numerous laboratory coal gasification trials have been performed in the academic and industrial fields. Lab-scale tests can provide insight into the processes involved with UCG. Many tests with UCG have been performed on ex situ reactors, where different UCG techniques, the effect of gasification agents, their flow rates, pressures, and various control mechanisms to improve gasification efficiency and syngas production have been investigated. This paper provides an overview of recent research on UCG performed on a lab scale. The study focuses on UCG control variables and their optimization, the effect of gasification agents and operating pressure, and it discusses results from the gasification of various lignites and hard coals, the possibilities of steam gasification, hydrogen, and methane-oriented coal gasification, approaches in temperature modeling, changes in coal properties during gasification, and environmental risks of UCG. The review focuses on laboratory tests of UCG on ex situ reactors, results, and the possibility of knowledge transfer to in situ operation.

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Section: High-pressure Coal Gasificationmentioning

confidence: 99%

Investigation of Underground Coal Gasification in Laboratory Conditions: A Review of Recent Research

Kačur,

Laciak,

Durdán

et al. 2023

Energies

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“…In 1983, Massaquoi and Riggs [38,39] simulated the gasification process of wet coal for the first time. The model considered the evaporation of coal moisture, the movement of the evaporation front, transpiration cooling effect of the water vapor and pyrolysis gases, pyrolysis and char/gas reactions occurring in dry coal regions, Darcy flow of steam and gases through coal, changes in porosity and permeability of coal, temperature-dependent coal physical properties, multicomponent diffusion in ash and gas films, and oxidation reactions in ash.…”

Section: One-dimensional Numerical Modelmentioning

confidence: 99%

“…On the contrary, when the temperature is high, the coal ash will melt and adhere to the coal wall, affecting the subsequent gasification process [11,61]. By numerical model, Massaquoi and Riggs [38,39] demonstrated that reducing ash region thickness could improve oxygen flux and lead to a higher combustion rate, which accelerated cavity growth. Furthermore, the temperature also significantly directly affects the physical properties of coal.…”

Section: The Temperaturementioning

confidence: 99%

A Review of Research on Cavity Growth in the Context of Underground Coal Gasification

Fang¹,

Liu

Ge³

et al. 2022

Energies

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Underground Coal Gasification (UCG) is a leading-edge technology for clean and effective utilization of coal resources, especially for deep coal seams with a depth of more than 1000 m. Since the core operation place of UCG is the cavity, mastering the cavity growth pattern is a prerequisite to ensure the efficient and economic development of UCG. At present, scholars have conducted numerous research works on cavity growth, but the simulation conditions limit the research results. Hence, it is necessary to summarize and sort out the research results of cavity growth patterns, which contribute to deepening the understanding of UCG and pointing out the direction for subsequent research. First of all, this paper summarizes the development history of UCG technology and describes the cavity growth mechanism from chemical reactions and thermo-mechanical failure. Then, the research methods of cavity growth are summarized from three aspects: a field test, laboratory experiment, and numerical simulation. The results show that the appearance of the cavity is teardrop-shaped, and its growth direction is obviously related to the gas injection method, including the injection direction and rate. Subsequently, the factors affecting the cavity growth process are expounded from the geological factors (permeability, moisture content, and coal rank) and operating factors (temperature, pressure, gasification agent’s composition, and gasification agent’s flow pattern). Finally, the existing problems and development trends in the cavity growth are discussed. The follow-up research direction should focus on clarifying the cavity growth mechanism of the controlled-retractable-injection-point (CRIP) method of UCG in the deep coal seam and ascertain the influence of the moisture content in the coal seam on cavity growth.

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“…In the literature, different approaches to UCG modeling can be found. Earliest numerical models were one-dimensional packed bed [40,57]. Thorsness et al [49] were able to make a good prediction of syngas composition and coal consumption for laboratory ex-Information Technology and Control 2019/4/48 periments with steam and oxygen (ratio 6:1).…”

Section: Ucg Modelingmentioning

confidence: 99%

Model Predictive Control of UCG: An Experiment and Simulation Study

Kačur

Flegner

Durdán

et al. 2019

ITC

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Underground coal gasification (UCG) is a potential technology that enables to mine coal without traditional mining equipment. The coal is gasified deep in underground and produced syngas is processed on the surface. The most important technical problem in UCG is unstable quality of syngas and control. This paper proposes advanced control based on an adaptive predictive controller. The maintaining of desired calorific value depends on flow rates of gasification agents injected to the underground geo-reactor and controlled exhaust. The paper proposes a physical model of UCG technology and applies a method of multivariate adaptive regression splines (MARS) to model the gasification process. This method satisfactorily approximates nonlinearity in the process variables. The paper proposes adaptive model predictive control (MPC) using online model estimation and applied it on the MARS model of UCG that imitates the real process. The results have shown that optimization of manipulation variables can replace manual control in UCG. Getting better quality of syngas depends on setpoints, optimized manipulation variables, and constraints used in MPC. In simulations, the adaptive MPC has shown better performance in comparison with manual and PI control.

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Mathematical modeling of combustion and gasification of a wet coal slab—II

Cited by 18 publications

References 4 publications

Investigation of Underground Coal Gasification in Laboratory Conditions: A Review of Recent Research

Investigation of Underground Coal Gasification in Laboratory Conditions: A Review of Recent Research

A Review of Research on Cavity Growth in the Context of Underground Coal Gasification

Model Predictive Control of UCG: An Experiment and Simulation Study

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