The carbon content of coking coal was more than 85 % while the disordered arrangement of carbon atoms contributed to pores generation, leading to the carbon-pore two phases mesoscopic structure property of coal [16]. Based on this, a novel in-situ technique combining synchrotron radiation Small Angle X-ray Scattering (SAXS) and Wide Angle X …

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 …

A method for in-situ measurement of calorific value of coal: a numerical study | Semantic Scholar. DOI: 10.1016/J.TCA.2021.179011. Corpus ID: 237655010. A method …

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 ...

Up to 1000 ℃, the value of d 002 was close to the ideal graphite layer spacing of 0.3354 nm, indicating that the graphitization of the aromatic layers increased with ... 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 ...

Heat release of coal combustion in an oxygen-lean and multi-gas environment is a common phenomenon, coalfield fires caused by it can lead to serious environmental destruction and loss of coal ...

In this study, a method for in-situ determination of the coal calorific value was developed based on a flow calorimeter. The temperatures of gas and walls and energy distributions in the calorimeter at gas flow rates of 0. 1, 0. 5, 1. 5 and 3 m 3 / h, coal mass of 0. 5, 1, 1. 5 and 2 g and wall thickness of 1, 10, 25 and 50 mm were numerically ...

IN-SITU PROCESSES; UNDERGROUND COAL GASIFICATION. Oxidation first takes place in the flame front, giving CO2 and H20. These are subsequently reduced to CO …

By igniting in the coal seam and injecting gas agent, underground coal gasification (UCG) causes coal to undergo thermochemical reactions in situ and, thus, to be gasified into syngas for …

Abstract. Underground coal thermal treatment (UCTT) is a promising concept that was recently proposed for extracting high-value hydrocarbon fuels from deep coal seams, which are economically unattractive for mining. UCTT is essentially an in situ pyrolysis process that converts underground coals into synthetic liquid and gaseous …

The actual production process of the in situ pyrolysis of oil-rich coal is shown in Figure 1. Nitrogen gas is heated and injected into the fractured zone to heat the …

Coal spontaneous combustion occurs frequently in mining and utilizing processes, which mostly result from the complex dynamic reaction of coal and oxygen. With a focus on the mass gain phenomenon of coal oxidation observed by thermogravimetric analysis, TG–FTIR and in situ IR experiments for a typical Jurassic …

The gasifier accomplishes four principal functions in a single stage, namely: (1) decaking coal, (2) devolatilizing coal, (3) gasifying coal, and (4) agglom-erating and separating ash from char. Coal of about 0.25-in. diameter is dried and pneumatically injected into the gasifier through a lock hopper system.

Tar-rich coal in situ pyrolysis (TCISP) refers to the technology that upgrades oil and gas products by heat transfer through heat carriers (such as high-temperature nitrogen) under formation pressure without mining, as shown in Figure Figure1 1. The products are expelled through pores and fractures in the coal layer and finally flow out …

In situ underground pyrolysis of tar-rich coal is significant for alleviating the scarcity of oil and gas resources and realizing the green and efficient development and utilization of coal in China. Tar-rich coal is often subjected to high axial pressure, surrounding pressure, and pore pressure in the in situ underground pyrolysis …

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 …

After heat treatment, the aggregate structure and ultramicropore size of coal have a high correlation with the activation energy. The activation energy is closely related to the 0.6 nmultramicropores.

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 …

Heat injection strengthen desorption and relieve inhibition of water on gas. •. The in-situ heat injection test is conducted for the first time. •. Concentration and daily gas production are increased by 10 times and 100 times. •. The drainage stage after heat injection is the high yield period of gas drainage. •.

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 …

Abstract. 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 ...

Hydrogen production via in-situ injection of supercritical water into underground coal seams is a new coal conversion technology. This study proposes a solid-fluid-heat coupling mathematical model ...

Compared with the actual values measured by the calorimeter, the value of the empirical formula (eq 3) is the closest, so the heat content of tar-rich coal is −23.83 MJ·kg –1, and the standard enthalpy of formation of tar-rich coal production is …

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 …

Hence, the in-situ measurement of the coal calorific value is needed. This study developed an in-situ calorific value determination method and established the …

DOI: 10.1016/J.TCA.2021.179011 Corpus ID: 237655010; A method for in-situ measurement of calorific value of coal: a numerical study @article{Linglong2021AMF, title={A method for in-situ measurement of calorific value of coal: a numerical study}, author={Wang Linglong and Xue-cheng Wu and Xiang Gao and Yingchun Wu and Kefa …

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) …

ABSTRACT. Hydrogen production via in-situ injection of supercritical water into underground coal seams is a new coal conversion technology. This study proposes a solid-fluid-heat coupling mathematical model for the heating stage of the injection of supercritical water into the coal seam and studies the evolution law of the temperature …

700 C, at heating rates of 5, 10, 15, and 20 C min-1 in air and N 2 atmosphere of 100 mL min-1, and the experi-mental sample volume was 5 mg. The TG/DTG curves and gaseous compounds infrared spectra of LSJ coal sample were obtained, which showed the different characteristics of coal oxidation and pyrolysis. In situ FTIR spectroscopy experiments

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 …

Thermochimica Acta. Volume 703, September 2021, 179011. A method for in-situ measurement of calorific value of coal: a numerical study. LinglongWang, XuechengWu, XiangGao, YingchunWu, KefaCen. Show more. Add to Mendeley. …

Underground coal gasification (UCG)/In-situ gasification (ISG) Underground coal gasification (UCG) also known as in-situ gasification (ISG) of coal takes place underground, generally below approximately 370 m. The underground setting provides both the coal feedstock source as well as pressures comparable to that in an above-ground …

The in situ heating of Ni-Fe LDH material resulted in the transformation into a coexistence of Ni oxide-type particles arranged throughout a NiFe 2 O 4 trevorite matrix, confirmed by TEM, HRTEM ...

Tar-rich coal has attracted increased attention in recent years due to its high tar content and yield. 4, 5 Coal can be classified into three categories based on the tar yield. Coal with tar yields (x) of x ≤ 7%, 7% < x < 12%, and x ≥ 12% are therefore classified as tar-containing coal, tar-rich coal, and high-tar coal, respectively. 4, 5, 6 China has an …

Anthracite Coal is very shiny, hard black coal, high carbon content and energy density, repels moisture, for domestic industrial uses, including smokeless fuel; Bituminous Coal is softer and shiny, moisture content is 8 -20%, possible for coking coals, volatile matter from 16% - 40%, can be used for thermal or metallurgical applications; Sub-bituminous Coal is …

Moisture content is an important parameter in coal analysis. 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 specified conditions after heating in a moisture oven to 104 to 110°C (ASTM …

The coal fire was burning 3 m below the surface. A vertical temperature profile for the crack is shown in Fig. 11. The measuring points for the vertical profile were taken from the edge of the crack at the following spots: surface, − 0.02 m, − 0.5 m, − 1 m, − 2 m below the surface, and at the coal fire (− 3 m) itself.