WEBDec 1, 2020 · In the alytic hydrogenation process, the addition of free radical scavengers can stabilize coal pyrolysis free radicals to form small molecular products and avoid condensation of primary volatiles, thereby improving tar quality [2].
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.
WEBJan 15, 2020 · As a comprehensive description of the functional groups effect on various volatile products during coal pyrolysis process, it is found that both alkyl and oxygencontaining groups can reduce the BDEs of the bridge bonds between aromatic rings during pyrolysis process, and the effect of oxygencontaining groups is more obvious. ...
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 ...
WEBJan 15, 2020 · article{Zhou2020EffectOF, title={Effect of functional groups on volatile evolution in coal pyrolysis process with insitu pyrolysis photoionization timeofflight mass spectrometry}, author={Yang Zhou and Lu Li and Lijun Jin and Jialong Zhu and Jiangang Li and Yang Li and Hongjun Fan and Haoquan Hu}, journal={Fuel}, .
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 ...
WEBJun 15, 2020 · In coal pyrolysis process, the drying and pyrolysis units are simulated by the RYIELD reactor module [35]. The temperature and pressure of drying unit are set as 350 °C and MPa, respectively. Dry coal is obtained by removing most of water through SEP1 module. After pyrolysis unit, which temperature and pressure are set as 630 °C .
WEBSep 1, 2018 · Kinetics of coking coal pyrolysis. Kinetics studies on coal pyrolysis were extensively performed by Solomon and his group based on the evolution of gas products and tar yield [24]. However, the production of gas products and tar is a more complied process than the evolution of functional groups in coal char.
WEBOct 1, 2023 · The free radical mechanism is the dominant coal pyrolysis mechanism. The process starts with the cracking of macromolecular structures of organic matter, involving numerous simultaneous reactions, including cleavage reaction, condensation reaction and interface reaction [22], [23]. Fig. 1 illustrates the formation mechanism of char, divided .
WEBJan 1, 2023 · The pyrolysis process occurring in absence of a alyst is a thermal pyrolysis process the problem with this process consumes higher energy in the form of temperature for degradation of the polymer into the product. ... Catalyst like spent FCC [42] and Zeolite [43] are commonly used in petroleum refineries and coal copyrolysis .
WEBAug 15, 2022 · (1), where m 0, m t were the initial mass of coal and the mass at a given time during the pyrolysis process, respectively. And m ∞ was the final mass of coal sample when the pyrolysis process was completed. (1) α = m 0m t m 0m ∞. The heating rate β was defined as Eq. (2). (2) β = d T d t
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 .
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)
WEBMar 5, 2024 · Raw coal with particle sizes of 62–93 μm, 160–200 μm and 380–420 μm were denoted as YN80, SF80, YN180, SF180, YN400 and SF400, respectively. Raw coal . Pyrolysis of coal. Fig. 2(a) shows in situ Raman spectra at different temperatures during pyrolysis process of SF.
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 .
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 .
WEBOct 15, 2014 · These works give us a useful insight for investigating the mechanism of coal pyrolysis, but in order to control the pyrolysis process and call for highquality gas and tar products, more microscopic details of chemical reactions during coal pyrolysis, especially for the generation process of key gas (CH 4, H 2, CO, and CO 2) and liquid products ...
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 .
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 .
WEBOct 15, 2021 · In the early stage of pyrolysis process of pulverized coal, a large number of chemical bonds are broken, leading to the release of small molecular volatile gases, causing the pores in the char particles to become developed.
WEBOct 1, 2013 · The Aspen Plus model used to simulate the dual bed pyrolysis gasifiion (DBPG) process is shown in Fig. 2, which consisted mainly of the modules for coal pyrolysis and char supplementary parts around such two modules included the elements decomposer for fuel, gas–solid separator (cyclones), heat .
WEBSep 1, 2018 · The pyrolysis stages proposed on the basis of ReaxFF MD simulations can give a rough sense of pyrolysis process in terms of weight loss of source coal molecules. For example, the simulation temperature range of 300–1200 K at a heating rate of 1 K/ps (Stage I) roughly corresponds to temperature range of 300–623 K at a heating rate of .
WEBAug 1, 2023 · In prior work, the ReaxFFMD method has been used to investigate the copyrolysis process of Zhundong coal with polyethylene (PE) and polystyrene (PS) [21], as well as the influence of calcium on the copyrolysis of coal and polystyrene [22], illustrating the distinct advantages and prospects of ReaxFFMD approach in the investigation of .
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 .
WEBJan 1, 1992 · Coal pyrolysis: Experiments, kinetic rates and mechanisms Author links open overlay panel Peter R. Solomon ∗, Michael A. Serio ∗, Eric M. Suuberg † Show more
WEBJan 15, 2020 · Therefore, understanding the specific effects of functional groups is of great significance for the further study of coal pyrolysis process. However, the lack of direct online observation and indepth mechanistic analysis on the influence of functional groups during the pyrolysis process lead to the difficulty in unified understanding on the ...
WEBFeb 17, 2024 · The different particle sizes of coal affect the whole pyrolysis process by simulating the heat transfer and material transfer (Gan et al., 2017; Sahu et al., 2023; Yin et al., 2023). The loose coal body composed of coal of different sizes can be regarded as a porous medium macroscopically, and its internal heat and mass transfer process is very ...
WEBNov 1, 2018 · By adding ash, ash/natural dolomite and ash/modified dolomite to the coal pyrolysis process, the content of Hg 0 in pyrolysis gas decreased to %, % and %, respectively. The research is able to offer the theoretical foundation for mercury contaminants' removal and process optimization of the step conversion technology.
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 .
WEBAbstract. Coal pyrolysis is important since it is the initial step in most coal conversion processes and is the step which is most dependent on the properties of the coal. In liquefaction, pyrolysis controls the initial yield of soluble products, their molecularweight distribution, and the competitive yield of gas species.
WEBOct 1, 2022 · Deng studied the pressurized pyrolysis process of demineralized coal at 1000 °C and found that as the pyrolysis pressure increased from MPa to MPa, the char yield increased from % to %, which was attributed to the increase of external pressure, the pressure difference between internal and external pores of coal ...
WEBApr 1, 2022 · Plasma pyrolysis is an emerging technology that has great potential for the largescale production of lowcarbon and affordable hydrogen. ... (30%) and coal gasifiion (18%). All these processes ...
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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