scholarly journals Measurements of Gasification Characteristics of Coal and Char in CO2-Rich Gas Flow by TG-DTA

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Zhigang Li ◽  
Xiaoming Zhang ◽  
Yuichi Sugai ◽  
Jiren Wang ◽  
Kyuro Sasaki
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Coal Gasification ◽  
Heating Temperature ◽  
Heating Process ◽  
Carbon Oxidation ◽  
Underground Coal Gasification ◽  
Basic Reference ◽  
Gasification Reaction ◽  
Physical And Chemical

Pyrolysis, combustion, and gasification properties of pulverized coal and char in CO2-rich gas flow were investigated by using gravimetric-differential thermal analysis (TG-DTA) with changing O2%, heating temperature gradient, and flow rate of CO2-rich gases provided. Together with TG-DTA, flue gas generated from the heated coal, such as CO, CO2, and hydrocarbons (HCs), was analyzed simultaneously on the heating process. The optimum O2% in CO2-rich gas for combustion and gasification of coal or char was discussed by analyzing flue gas with changing O2from 0 to 5%. The experimental results indicate that O2% has an especially large effect on carbon oxidation at temperature less than 1100°C, and lower O2concentration promotes gasification reaction by producing CO gas over 1100°C in temperature. The TG-DTA results with gas analyses have presented basic reference data that show the effects of O2concentration and heating rate on coal physical and chemical behaviors for the expected technologies on coal gasification in CO2-rich gas and oxygen combustion and underground coal gasification.

Effect Of Equivalent Ratio (ER) On the Flow and Combustion Characteristics in A Typical Underground Coal Gasification (UCG) Cavity

2021 ◽  
Vol 86 (2) ◽  
pp. 28-38
Author(s):  
Arup Kumar Biswas ◽  
Wasu Suksuwan ◽  
Khamphe Phoungthong ◽  
Makatar Wae-hayee
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Coal Gasification ◽  
High Efficiency ◽  
Combustion Characteristics ◽  
Raw Material ◽  
Underground Coal Gasification ◽  
Equivalent Ratio ◽  
Rubble Pile

Underground Coal Gasification (UCG) is thought to be the most favourable clean coal technology option from geological-engineering-environmental viewpoint (less polluting and high efficiency) for extracting energy from coal without digging it out or burning it on the surface. UCG process requires only injecting oxidizing agent (O2 or air with steam) as raw material, into the buried coal seam, at an effective ratio which regulates the performance of gasification. This study aims to evaluate the influence of equivalent ratio (ER) on the flow and combustion characteristics in a typical half tear-drop shape of UCG cavity which is generally formed during the UCG process. A flow modeling software, Ansys FLUENT is used to construct a 3-D model and to solve problems in the cavity. The boundary conditions are- (i) a mass-flow-inlet passing oxidizer (in this case, air) into the cavity, (ii) a fuel-inlet where the coal volatiles are originated and (iii) a pressure-outlet for flowing the product Syngas out of the cavity. A steady-state simulation has been run using k-? turbulence model. The mass flow rate of air varied according to an equivalent ratio (ER) of 0.16, 0.33, 0.49 and 0.82, while the fuel flow rate was fixed. The optimal condition of ER has been identified through observing flow and combustion characteristics, which looked apparently stable at ER 0.33. In general, the flow circulation mainly takes place around the ash-rubble pile. A high temperature zone is found at the air-releasing point of the injection pipe into the ash-rubble pile. This study could practically be useful to identify one of the vital controlling factors of gasification performance (i.e., ER impact on product gas flow characteristics) which might become a cost-effective solution in advance of commencement of any physical operation.

scholarly journals Experimental Study on the Fractal Features and Permeability Characteristics of Low Metamorphic Coal Pore Structure under Thermal Damage

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhen Liu ◽  
Mingrui Zhang ◽  
Shijian Yu ◽  
Lin Xin ◽  
Gang Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Pore Structure ◽  
Coal Gasification ◽  
Thermal Damage ◽  
Fractal Model ◽  
Utilization Efficiency ◽  
Heating Process ◽  
Underground Coal Gasification ◽  
External Temperature ◽  
Permeability Characteristics

Underground coal gasification and exploitation of geothermal mine resources can effectively improve coal conversion and utilization efficiency, and the basic theory of the above technologies generally relies on the change law of the coal pore structure under thermal damage. Therefore, the influence mechanism of the development of the coal pore structure under thermal damage is analyzed by the nuclear magnetic resonance experiment, and the temperature-permeability fractal model is created. The results show that compared with microtransitional pores, the volume of meso-macropores in the coal body is more susceptible to an increase in temperature, which was most obvious at 200-300°C. During the heating process, the measured fractal dimension based on the T2 spectral distribution is between 2 and 3, indicating that the fractal characteristics did not disappear upon a change in external temperature. The temperature has a certain negative correlation with DmNMR, DMNMR, and DNMR, indicating that the complexity of the pore structure of the coal body decreased gradually with the increase of the temperature. Compared with the permeability calculated based on the theoretical permeability fractal model, the permeability obtained from the temperature-permeability fractal model has a similar increasing trend as the permeability measured by the NMR experiment when the temperature increases. The experimental study on pore structure and permeability characteristics of the low metamorphic coal under thermal damage provides a scientific theory for underground coal gasification and geothermal exploitation.

Innovative Approach to the Integrated Use of Energy Resources of Underground Coal Gasification

2018 ◽  
Vol 277 ◽  
pp. 221-231 ◽  
Author(s):  
Pavlo Saik ◽  
Mykhailo Petlovanyi ◽  
Vasyl Lozynskyi ◽  
Kateryna Sai ◽  
Artem Merzlikin
Keyword(s):  
Coal Gasification ◽  
Hydrate Formation ◽  
Energy Resources ◽  
Raw Material ◽  
Underground Coal Gasification ◽  
Enterprise Restructuring ◽  
Coal Enterprise ◽  
Low Efficiency ◽  
Energy Products ◽  
Physical And Chemical

Topical issues concerning the low efficiency of underground coal mining from thin and very thin seams as well as the problems of reserves left in mine fields by the closed-down enterprises resulting in substantial coal reserve losses have been highlighted. Alternative use of the unextracted energy resources is their physical and chemical transformation with the change in aggregate state including the possibility to generate valuable chemical and energy products capable of substituting certain share of natural gas being imported. Attention has been paid to budget reallocation in the process of coal enterprise restructuring to invest the projects of nontraditional techniques aimed at physical and chemical coal transformation; among other things, it concerns in-place construction of energy generating enterprises for underground coal gasification. Results of the studies concerning the analysis of the world 50-year interest in the techniques of gasification and hydrate formation explained and described in the top scientific journals being among those added to such scientometric data bases as Scopus and Web of Science; they confirm the expediency of the scientific tendency development in Ukraine. Innovative conversion scheme for solid fuel has been proposed; the scheme involves the integrated use of the generated energy and chemical products in the process of in-place coal gasification. Development of systems to gasify, cogenerate, and form hydrates at the territory of coal mines will make it possible to process coal in place with energy, heat energy, and chemical raw material generation depending upon the situation in energy market and chemical market.

scholarly journals Modelling Test of Autothermal Gasification Process Using CFD

2017 ◽  
Vol 62 (2) ◽  
pp. 253-268
Author(s):  
Tomasz Janoszek ◽  
Krzysztof Stańczyk ◽  
Adam Smoliński
Keyword(s):  
Numerical Model ◽  
Coal Gasification ◽  
Energy Transport ◽  
Fluid Dynamic ◽  
Fixed Bed ◽  
Complex Model ◽  
Ex Situ ◽  
Underground Coal Gasification ◽  
Gasification Process ◽  
Physical And Chemical

AbstractThere are many complex physical and chemical processes, which take place among the most notable are the chemical reactions, mass and energy transport, and phase transitions. The process itself takes place in a block of coal, which properties are variable and not always easy to determine in the whole volume. The complexity of the phenomena results in the need for a construction of a complex model in order to study the process on the basis of simulation. In the present study attempts to develop a numerical model of the fixed bed coal gasification process in homogeneous solid block with a given geometry were mode. On the basis of analysis and description of the underground coal gasification simulated in the ex-situ experiment, a numerical model of the coal gasification process was developed. The model was implemented with the use of computational fluid dynamic CFD methods. Simulations were conducted using commercial numerical CFD code and the results were verified with the experimental data.

Ex Situ UCG Model Experiments with Oxygen Enriched Air in an Artificial Coal Seam

2017 ◽  
Vol 737 ◽  
pp. 379-384
Author(s):  
Fa Qiang Su ◽  
Ken-ichi Itakura ◽  
Akihiro Hamanaka ◽  
Gota Deguchi ◽  
Kohki Sato ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Gasification ◽  
Calorific Value ◽  
Close Correlation ◽  
Gas Production ◽  
Ex Situ ◽  
Underground Coal Gasification ◽  
Coal Consumption ◽  
Gas Leakage ◽  
Gasification Reaction

Underground Coal Gasification (UCG) demands precise evaluation of the combustion area in the coal seam. Especially, the monitoring of fracture activity in the coal seam and around rock is important not only for efficient gas production but also for estimation of subsidence and gas leakage to the surface. For this objective, laboratory experiments were conducted using the simulated UCG models. This paper also investigated gas energy for coal consumption, the production gas quantity and heat value, the application of oxygen element balance in the gasification reaction process, and the gas composition obtained in this study. During burning of the coal, temperatures inside the coal, contents of product gases and acoustic emission (AE) activities were monitored successively under the control of feeding gas (air/oxygen and steam) flow rate. Comparison of the temperature variation and accumulated AE event curves revealed a close correlation between them. The local change of temperature inside the coal induced fractures with AE. The AE activity was related closely to the local changes of temperature inside the model. The evaluation of gas energy recovery calculated from the obtained product gas provided a fair evaluation for the coal consumed, and the quantity of gas product and calorific value obtained from the UCG process.

scholarly journals Modelling of Gas Flow in the Underground Coal Gasification Process and its Interactions with the Rock Environment

2013 ◽  
Vol 12 (2) ◽  
pp. 8-20 ◽  
Author(s):  
Tomasz Janoszek ◽  
M. Jacek Łączny ◽  
Krzysztof Stańczyk ◽  
Adam Smoliński ◽  
Marian Wiatowski
Keyword(s):  
Gas Flow ◽  
Coal Gasification ◽  
Underground Coal Gasification ◽  
Gasification Process

Characteristic of Possible Obtained Products during the well Underground Coal Gasification

2019 ◽  
Vol 291 ◽  
pp. 52-62 ◽  
Author(s):  
Roman Dychkovskyi ◽  
Jaroslav Shavarskyi ◽  
Edgar Cáceres Cabana ◽  
Adam Smoliński
Keyword(s):  
Coal Gasification ◽  
Chemical Transformations ◽  
Ministry Of Education ◽  
Underground Coal Gasification ◽  
Technological Parameters ◽  
Waste Products ◽  
Underground Gasification ◽  
Scientific Principles ◽  
Energy Products ◽  
Physical And Chemical

This article is a summarizing of the results of the author's team on the establishment of technological parameters of underground gasification. It provides a justification of the final chemical and energy products that can be obtained as a result of complex physical and chemical transformations of coal. The thermodynamic processes of formation of the gasification source when changing the composition of the blast furnace mixture and the modes of its application to the georeactor are considered. Moreover, the change in the stress-strain state of rocks depending on the composition of the lateral rocks is taken into account. To better ensure the results are consistent with the well-known principles of thermodynamics and phase formation under the influence of the temperature field and the main chemical reactions occurring in complex gasification processes are presented. The main phase transitions in the georeactor are given for the maximum reception of different energy gases. Particular attention is given to the formation of an appropriate relationship between hydrogen and carbon monoxide, which form a synthesis gas. The Anderson-Schultz-Flory reaction is used to determine the maximum CO concentration in the outlet mixture. In general, the system for determining the material and thermal balance is proposed. These approaches were checked both for working out the coal reserves and for utilization of the mining waste products. Results of this investigation were included to the Roman Dychkovskyi thesis of the scientific degree of the Doctor of the Technique Sciences “Scientific Principles of Technologies Combination for Coal Mining in Weakly Metamorphoses Rockmass”. Also, this results were partially presented on international scientific and practical conferences “Forum of Miners” from different years. They contain the researches, which were conducted within the project GP – 489, financed by Ministry of Education and Science of Ukraine.

scholarly journals Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4462
Author(s):  
Grzegorz Wałowski
Keyword(s):  
Reynolds Number ◽  
Flow Resistance ◽  
Gas Flow ◽  
Coal Gasification ◽  
Gas Permeability ◽  
Resistance Coefficient ◽  
Underground Coal Gasification ◽  
Permeability Model ◽  
Permeability Characteristics

Underground coal gasification (UCG) technology converts deep coal resources into synthesis gas for use in the production of electricity, fuels and chemicals. This study provides an overview of the systematic methods of the in situ coal gasification process. Furthermore, the model of the porous structure of coal has been presented and the gas movement taking place in the carbon matrix—which is part of the bed—has been described. The experimental tests were carried out with the use of air forced through the nozzle in the form of a gas stream spreading in many directions in a porous bed under bubbling conditions. The gas flow resistance coefficient was determined as a function of the Reynolds number in relation to the diameter of the gas flow nozzle. The proprietary calculation model was compared to the models of many researchers, indicating a characteristic trend of a decrease in the gas flow resistance coefficient with an increase in Reynolds number. The novelty of the study is the determination of the permeability characteristics of char (carbonizate) in situ in relation to melted waste rock in situ, taking into account the tortuosity and gas permeability factors for an irregularly shaped solid.

scholarly journals Modelling of Gas Flow in the Underground Coal Gasification Process and its Interactions with the Rock Environment

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Tomasz Janoszek ◽  
M. Jacek Łączny ◽  
Krzysztof Stańczyk ◽  
Adam Smoliński ◽  
Marian Wiatowski
Keyword(s):  
Gas Flow ◽  
Coal Gasification ◽  
Underground Coal Gasification ◽  
Gasification Process
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