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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 gross calorific value (GCV), also known as the higher heating value (HHV) of coal is the amount of heat emitted upon complete combustion of coal. The GCV of coal is used to estimate various technoeconomic parameters such as boiler efficiency, …
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HEATING VALUE Depending on the heating values of the resultant synthesis gases produced by gasifi-cation processes, product gases are typically classified as three types of gas mixtures3: 1. Low-Btu gas consisting of a mixture of carbon monoxide, hydrogen, and some other gases with a heating value typically less than 300 Btu/scf. 2.
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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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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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in situ.--Refers to coal "in place" in the ground. in situ mining.--Utilization of coal by burning in place and extracting the gases, tars, and heat. joule (J).--The basic metric unit of work or energy equal to 1 x 10**7 ergs, 0.238662 gram calorie, 0.0002386 kilogram-calorie, or 0.0009471 Btu.
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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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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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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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IN-SITU PROCESSES; UNDERGROUND COAL GASIFICATION. Oxidation first takes place in the flame front, giving CO2 and H20. These are subsequently reduced to CO …
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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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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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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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The CLC technology to burn solid fuels like coal is achieving a high degree of development [3], [4] since it is expected that they continue being one of the main energy sources in a medium term [5].Among the different approaches to perform the combustion of solid fuels in CLC systems, the in-situ Gasification CLC (iG-CLC) is focusing great …
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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 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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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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It was identified that the analyses described above do not provide a sufficiently accurate indication of the true in-situ moisture and equations were developed to better correlate Equilibrium Moisture and Moisture Holding Capacity with field observations (see Fletcher, I.C. and Saunders, R.H. (2003) "Estimation of in-situ moisture of coal ...
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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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Large reserves of low-rank coal are available, but such coal has heavy volatile matter and low heat value [4]. Consequently, achieving clean and effective application of such coal is of great importance. ... Technical scheme of in situ pyrolysis of coal by superheated water vapor to extract oil and gas. Many researchers [11, [15], ...
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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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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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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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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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1. Introduction. The coking coal would produce metallurgical coke when a series of intricate and ongoing physical and chemical reactions took place [1].The distribution of temperature gradient in chamber was formed due to the different heat absorption capacities of unreacted coal layer, plastic layer, semi-coke layer and coke …
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Furthermore, the changes in chemical structure of coal components by HRTEM in situ with heating procedure were rarely reported. HRTEM in situ heat-treatment would have a significant advantage over HRTEM is that it can provide directly image-observed in different temperature stages. ... As seen in Fig. 4 b, the Lc values of …
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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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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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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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As can be seen from Table 4, d 002 value of rapid-heat-treatment char was higher, while L 002 value was lower than those of raw materials. The results indicated that for coal and petroleum coke samples, the rapid pyrolysis process enhanced the graphitization of carbonaceous materials to some extent.
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