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Highlights: • An in-situ calorimeter for coal is presented. • Heat transfer processes and measurement results under different working conditions are studies. • The relative …
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The study aims to explore the kinetics of coal char during high temperature gasification by thermogravimetric analyzer and in situ heating stage microscope. Yangchangwan coal (YCW) and Shenfu coal (SF) were selected as the feedstock. The kinetics was fitted by using shrinking core, random pore, and homogeneous models, …
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In this study, a method for in-situ determination of the coal calorific value was developed based on a flow calorimeter.
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Steam and an oxidative medium could be the most promising atmosphere for the in-situ pyrolysis of tar-rich coal. This study investigated the influence of these two atmospheres by comparing product yields, tar properties, and pore evolution characteristics of a tar-rich coal following pyrolysis under nitrogen (N 2), steam/nitrogen (steam/N 2), …
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Underground coal gasification is a conversion and extraction process, for the production of useful synthetic product gas from an in-situ coal seam, to use in power generation, heat production or as a chemical feedstock.
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In general, the major coal basins in China contain different types of coal, ranging from less thermally matured lignite coal to high thermally matured anthracite coal, with R o values ranging from 0.2% to 4.4%. The formation of multi-rank coals is the result of multi-stage evolution and the superposition of multiple heat sources for metamorphism …
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The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative coal seam with multiple sections (A1, A2, and A3) in the Sydney basin, where the CO2 composition exceeds 90%. The fast …
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Moisture absorbs heat, so high moisture content in coal reduces the relative efficiency of heating when a coal is combusted. This is why low-rank, high-moisture coals have lower calorific values (Btu/lb) …
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2.1 General design. As indicated in Fig. 3, the UAMM was designed to adopt an earthworm-like structure that could be disassembled and re-assembled to accommodate the differences between roadway tunnelling and coal seam mining.Figure 3a demonstrates the UAMM-T (tunnelling) which is used in excavation of vertical shafts and rock …
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This low ashing temperature was used to ensure that AAEMs are kept in the ash to facilitate the study of morphological transformations upon heating. For coal samples and coal/biomass blends, the ashing was carried out following the approach adopted by many others [3, 9, 15]. The sample was heated from room temperature to 500 °C in 30 …
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Underground coal thermal treatment (UCTT) is a recently proposed concept that offers the prospect of converting deeply buried coals into high-value hydrocarbon fuels that have less CO 2 emissions per energy content. In this process, the coal seam is heated by external energy and decomposition products are recovered in the form of gaseous …
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Each coal sample weighed approximately 200 g. These samples were pulverized and sieved to obtain particles of <56 μm in diameter and dried in a desiccator at 60°C for 12 h.After that, they were demineralized to avoid the interference of mineral matter in coal before subjecting them to in situ XRD and FTIR experiments.
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This paper presents a series of surface experiments simulating underground coal gasification (UCG). The main goal of the experiments was to investigate the influence of the gasification medium and the coal rank on the gasification process. Four multi-day trials were carried out using a laboratory gasification facility designed for the large-scale …
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The experimental results indicate that the hybrid kernel function is more suitable for forecasting the calorific value of coal gangue than that of a single kernel …
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The naphthalene presented a complex variation with increasing temperature and contributed to the evolution of L a value. ... Chemical structural transformations of different coal components at the similar coal rank by HRTEM in situ heating. Fuel, 218 (2018), pp. 140-147. View PDF View article View in Scopus Google Scholar [19] Y.F. …
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The average temperature of the gas increases when the coal releases heat and reaches the peak (306 K). Then it starts to decrease at the end of coal combustion (t c = 230 s). As gas. Conclusion. Aiming at the in-situ measurement of the calorific value of coal, a method based on an open cyclic calorimeter was proposed and the related …
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A multi-physics numerical method coupling fluid flow, heat transfer, and a chemical reaction was used to determine the temperature distribution and the conversion rate of a coal seam during ...
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It is needed for determining the calorific (heating) value and handling properties of a coal. The moisture value given for a proximate analysis is the moisture measured as mass lost from a sample under …
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Eq. (5.21) represents the thermal decomposition of coal; it decomposes into volatile matter such as hydrogen and hydrocarbon gas and char (residual solid content composed of fixed carbon and ash). Eqs. (5.22) and (5.23) indicate combustion and partial combustion by reaction with oxygen, and supply heat of reaction required for gasification. Eqs. (5.24) …
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DOI: 10.1016/j.energy.2024.130690 Corpus ID: 267743288; Analysis of heat transfer performance and system energy efficiency of catalytic combustion heaters for low calorific value waste gas application to oil shale in-situ conversion
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The basic principle of in-situ gasification is the same as surface gasification [3], but with significant difference of no need for purpose-built gasifier.When implementing in-situ gasification, the injection and production wells are constructed by vertical drilling and connected through directional drilling to form reaction channel, then the coal seam on …
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Learn how the calorific value of coal is measured using a bomb calorimeter and how it is used to define coal rank and estimate heat production. Find out the units and conversion formula for calorific value …
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Timely monitoring of the calorific value of coal is beneficial to combustion regulation during the operation of coal-fired power plants. An in-situ measurement …
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Fusion property prediction and mineral reaction mechanism of coal/biomass ash blends upon in-situ tests in the gasification process. ... The fuel ratio (0.5–2.0), and higher heating values (16,100–19,000 kJ/kg) of coal and torrefied biomass were within the range useful for coal-fired plants. Additionally, ash analyses, ash fusion ...
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Three vitrinite samples of different rank, denoted as V-YJL, V-AW, and V-J15, were investigated by in situ heating while in a High resolution transmission electron microscope (HRTEM) to study the aromatic structural transformations from 200 to 800 °C. Thermogravimetry coupled with Fourier transform infrared spectroscopy and mass …
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A subbituminous coal, Wucaiwan coal was used in this experiment. Its proximate and ultimate analyses are listed in Table 1. The coal was first treated with 1 mol/L hydrochloric acid (HCl) and 20% hydrofluoric acid (HF) for 24 h at room temperature, respectively. After washing with deionized water and drying, a demineralized sample …
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In situ coal fires significantly pollute the environment in many countries of the world. Monitoring these pollutants is challenging due to extensive area coverage and spatial variations. Thus, the present study demonstrates the method of deriving the spatial and temporal profiles of columnar density of three major greenhouse gases (carbon …
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In-situ pyrolysis is a new, efficient and environmentally friendly coal utilization technology by heating and pyrolyzing coal underground through thermal carrier such as high-temperature nitrogen, CO 2, supercritical water and so on (Ozowe et al., 2020, Omari et al., 2022, Jin et al., 2017) without mining just like oil shale recovery (Wang et ...
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The actual production process of the in situ pyrolysis of oil-rich coal is shown in Fig-ure 1. Nitrogen gas is heated and injected into the fractured zone to heat the coal seam. The coal seam starts pyrolysis when the temperature exceeds 573 K, and oil and volatile gas are then generated. The products flow out with the high-temperature …
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The idea of recovering the energy values of coal by in-situ processes, without the intervention of human effort below ground and without bringing waste to the surface, is one which has exceptional appeal to the public. For this reason alone, a careful analysis of the possibilities is desirable, regularly renewed in the light of developing technology and …
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Q coal = m coal ∫ 0 t c f ( t) d t is the calorific value of coal. f ( t) and t c are the heat release rate (HRR) of pulverized coal and the combustion time, respectively. Q …
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The macroscopic multi-physics simulation of tar-rich coal in situ pyrolysis (TCISP) is conducted, in the fractured porous zone, by coupling heat transfer, fluid flow, and chemical reaction. A novel TCISP pattern of gas injection between fractured zones is proposed by treating the fractured porous zone as a homogeneous porosity gradient …
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The temperature change in coal and graphite during heating and combustion by a CO2 laser heat source was measured using the multi-two-colour method. Laser …
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In-situ investigation of coal particle fragmentation induced by thermal stress and numerical analysis of the main influencing factors ... and ε is the coal particle emissivity. Here, a value of ε = 0.85 is applied for the calculation [17], which is a characteristic value for ... The heat capacity of coal normally ranges from 0.2 to 0.4 cal …
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The geometric model of tar rich coal and computation domain during in-situ pyrolysis is shown in Fig. 2.Permeability of coal seam can be increased by hydro or shockwave fracturing in the middle region of the coal seam, leading to inhomogeneous permeability as shown in Fig. 2 (b). A square with the side length of 10 m is selected as …
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1. Introduction. The integrally structural arrangement of coal increases with proceeding coalification up to the formation of organic macromolecules of flat shape with carbon atoms in the central part [1 – 3].During coalification, the size of coal molecules increases as well as the degree of their ordering and macromolecules arrange …
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