WEBOct 15, 2014 · In addition, coal pyrolysis is also a complex process involving a large number of chemical reactions. These chemical reactions are coupled together, with vast free radical intermediates generated in the initial stage. Such radicals are shortlived species so that they are hard to be captured by traditional experimental approaches.
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WEBJan 1, 2023 · A lowrank coal pyrolysis coupled with gasifiion for DRI system is proposed. • Effects of the key parameters on CCHI process are optimized and analyzed.
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WEBJan 15, 2023 · Due to the complexity of coal pyrolysis, there is a challenge to disclose the reaction mechanism of pyrolyzate. So far, the molecular dynamics (MD) based on reactive force field (ReaxFF) is an effective method to study the reactive mechanism of complex compound, and has been widely used in coal pyrolysis process [20]. The ReaxFF .
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WEBSolidheat carrier pyrolysis is a simple process with high equipment unit efficiency (Sun et al., 2022) that completes coal pyrolysis by rapidly hybrid heating of hot coal and semicoke. Three types of solid heat carriers like lowheating, midtemperature, and speedsolid heatcarrier retorting process are used ( Xue et al ., 2017 ).
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WEBJan 1, 1989 · INTRODUCTION A coal pyrolysis process has been developed for the purpose of producing chemical feedstocks such as benzene, toluene, xylene (BTX) and light oil which have high economic values. The yields of products are influenced by many factors (coal type, coal particle size, carrier gas, pressure, temperature and so on ). ...
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WEBOct 1, 2019 · Compared with traditional pyrolysis processes, the integrated process of CO2 reforming methane and coal pyrolysis (CRMP) can obviously improve the tar yield. However, the structural information ...
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WEBAug 15, 2023 · The molecular model of tarrich coal was constructed by combining experimental characterization and theoretical calculations. • The molecular model was validated by calculating FTIR and 13 C NMR spectra with quantum chemistry.. Complex systems containing multiple molecules were constructed, and the pyrolysis process .
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WEBNov 1, 2019 · The integrated process involves two processes: alytic reforming of SCG and coal pyrolysis. The existence of reforming alyst (Ni/Al 2 O 3) can alyze some reactions, thus, the atmosphere difference will affect the reforming process and the subsequent coal pyrolysis process. Our previous studies also showed that some .
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WEBMar 31, 2022 · An inherent watersoluble sodiumloaded coal sample was prepared using crown ether for this study. The pyrolysis process of an inherent watersoluble sodiumloaded coal sample and a watersoluble sodium compoundloaded coal sample was researched by thermogravimetric analysis (TGA). Also, the pyrolysis kinetics of the .
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WEBFeb 1, 2013 · The amount of volatile fractions (distillate below 300 °C) of tar obtained from coal pyrolysis under different atmospheres is different and the results are shown in Table can be seen that the percentage of distillate for coal tar under N 2, H 2 and CO 2 atmospheres is about 70% to total tar, and that from CRMP process is %, much .
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WEBSep 6, 2019 · Abstract. The pyrolysis processes of a coal particle containing 19,638 atoms in different atmospheres are studied with a reactive force field molecular dynamics (ReaxFF MD) method. The detailed chemical reactions with the corresponding occurrence frequencies are obtained. The generation paths of the main products are disclosed, .
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WEBOct 1, 2022 · The coal pyrolysis can be divided into three stages, drying stage, depolymerization and decomposition stage and polycondensation stage [42]. It can be seen from Fig. 11 that pressure has different influences on coal pyrolysis process at low (600 °C) and high (800 °C) temperatures. Download : Download highres image (244KB)
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WEBApr 1, 2022 · The release characteristics of biomass model compounds and coal in the copyrolysis process were deeply researched by the thermalmass spectrometer (TGMS). When the temperature reaches to 500 °C, the main pyrolysis products of microcrystalline cellulose and lignin are released. At the temperature higher than 900 °C, small .
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WEBDec 1, 2023 · In the process of coal mining, washing and utilization, a huge amount of coal gangue (CG) is produced, which has become the largest solid waste in China. ... [14] et al. discussed the influence of alkali metal compounds on the pyrolysis process of CG, and the results showed that high alkali metal content could reduce the initial precipitation ...
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WEBJun 1, 2023 · Generally, the coal pyrolysis process consists of primary devolatilization reactions and subsequent secondary reactions [23], [24]. In this work, to combine the mass transfer with pyrolysis kinetics more conveniently and simplify the calculation process, the coal pyrolysis process is assumed to be composed of two. Results and discussion
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WEBApr 5, 2024 · In order to explore the formation mechanism of NOx precursors and NOx during coal pyrolysis and combustion, four typical Ncontaining functional groups in coal, including pyridineN (N6), pyrroleN (N5), protonationN (NQ) and oxidized pyridineN (NX), were taken for study. Firstly, the thermal reaction processes of Ncontaining .
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WEBThe term 'pyrolysis' has Greek roots and can be roughly translated as "fire separating". Generally, substances that are subjected to pyrolysis undergo a chemical decomposition reaction and break down into multiple product compounds. The process of pyrolysis is widely used to break down organic substances. For example, the charring of ...
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WEBJul 28, 2023 · In this work, Qiqunahu (QQH) coal, cotton stalk, cellulose and lignin extracted from cotton stalk were selected as raw materials to study the effects of the copyrolysis of coal and cotton stalk. Online thermogravimetric mass spectrometry (TGMS) was used to analyse mass loss and gas release characteristics during copyrolysis. .
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WEBOct 1, 2023 · Underground coal gasifiion (UCG) is a promising technology which insitu converts coal into fuel gases through controlled chemical reactions. In order to precisely control coal pyrolysis and increase the char yield, it is vital to understand the influences of operating factors such as heating rate and pressure, on coal pyrolysis.
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WEBMar 5, 2024 · Char was prepared in a fixed bed reactor by pyrolysis of coal. The experimental process was as follows: about 2 g of coal was placed in a molybdenum crucible in reactor; N 2 (300 mL·min −1) was injected into reactor to purge air, and power controller was adjusted to heat the reaction zone to 1000 °C; reaction zone was kept at .
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WEBApr 1, 2023 · The research presented in this paper demonstrates that the model has tremendous potential for use in the coal pyrolysis process and offers a useful method for investigating the coal pyrolysis reaction. Only the pyrolysis reactions of lowmedium rank coals were modeled and examined in this work. Therefore, when used with highrank .
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WEBA nonlinear programming (NLP) model has been established to describe the process of low rank coal pyrolysis, and the model was validated through comparison with pilot or semiindustry technologies. Results showed good agreement with actual production values, suggesting that the model can be regarded as a general one for simulating low rank .
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WEBThe study investigates the thermal pyrolysis of coal and copyrolysis of the coalsawdust blend ( blend) in a fixedbed reactor. The pyrolysis od coal and sawdust was performed at 773 K, 823 K, and 873 K temperature and 30 K min −1 heating rate under nitrogen purge gas (300 mL min −1).Copyrolysis coal and biomass was performed at .
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WEBOct 1, 2023 · The two key factors that significantly impact coal pyrolysis are its structural composition and the medium in which it is carried out. In this study, effects of acid pretreatment (AP), hydrothermal pretreatment (HTP), and acidhydrothermal synergistic pretreatment (APHTP) on Shenfu Lowrank coal (SF) structure were investigated.
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WEBMar 1, 2021 · Revealing the pyrolysis reaction pathway related to coal structure evolution under different temperatures is important for the industry to design reactors and process operations. In this study, all the pyrolysis products obtained under different pyrolysis temperatures were comprehensively analyzed by multiple techniques. The results .
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WEBMay 1, 2017 · Semicoke, sometimes called bluecoke, char, and semicarbon, is a pyrolysis byproduct of bituminous coal that has high volatile content and nocaking or weakcaking qualities at low (500650°C ...
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WEBMar 23, 2023 · The coal pyrolysis is a fundamentally important process since it involves a set of chemical reactions, which play key roles in most coal conversion processes, such as coking, liquefaction, hydrogenation, gasifiion and combustion. ... Coal softening is a consequence of both physical melting process and pyrolysis breakdown of the coal .
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WEBApr 1, 2020 · An experimental investigation on heating rate effect in the thermal behavior of perhydrous bituminous coal during pyrolysis. Perhydrous bituminous coal has multipurpose industrial appliions established by its distinctive thermal behavior. The Huainan coalfield in China has a large volume of these types of coals...
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WEBNov 6, 2021 · Therefore, during the slow pyrolysis process, even if the main pyrolysis stages of coal and biomass are independent of each other, there are still synergistic or inhibitory effects. During copyrolysis, when the heating rate is fast enough, the pyrolysis processes of coal and biomass can occur simultaneously, and the release of volatiles .
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WEBMar 1, 2024 · To characterize the pyrolysis process of Zhundong coal, an updated version [50] of the CRECKS model [55] from Politecnico di Milano (PoliMi) was successfully employed. Detailed information about the CRECKS model is available in Refs. [50, 56].This CRECKS model extended for Zhundong coal comprises 23 species and 43 reactions .
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WEBJul 27, 2023 · The copyrolysis process of biomass and coal is very complied[16,17], which is difficult to be . expressed by a series of accurate reaction equations. Moreover, traditional experimental methods .
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WEBJul 1, 2016 · Pyrolysis is the first chemical step in the overall solid fuel thermochemical process and has a significant influence on the subsequent stages. An accurate kinetic modeling of this process is thus required for a better understanding of the solid fuel conversion and for boiler CFD.
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WEBFeb 5, 2024 · Through analysing the simulation results of coal pyrolysis, the pyrolysis process of large coal molecules can be divided into several stages [36]: (1) Initial cleavage: The chemical structure of coal is a network of aromatic cores randomly connected with aliphatic chains. In the initial stage of pyrolysis (150–350 °C), weak aliphatic ...
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