Changes in the physicochemical characteristics and spontaneous combustion propensity of Ximeng lignite after hydrothermal dewatering

Yuan, Shao; Liu, Jianzhong; Wu, Ji; Zhou, Qingqing; Wang, Zhihua; Zhou, Junhu; Cen, Kefa

doi:10.1002/cjce.23182

Cited by 17 publications

(14 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The FTIR spectra of the four LCRs are shown in Figure , and the chemical structures represented by the individual absorption peaks can be found in the literature . The significant absorption peak at 3600–3000 cm –1 represents the –OH groups.…”

Section: Resultsmentioning

confidence: 99%

“…The zone at 3000–2800 cm –1 is generally divided into five peaks: asymmetric stretching vibration of ‐CH3 (2955 cm –1 ) and ‐CH2‐ (2922 cm –1 ); stretching vibration of ‐CH (2900 cm –1 ); and symmetrical vibrations of ‐CH3 (2871 cm –1 ) and ‐CH2‐ (2850 cm –1 ). In the region of 1800–1500 cm –1 , the absorption peak at 1730 and 1700 cm –1 are assigned to the stretching vibration of C = O.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Pyrolysis characteristics of low‐rank coals based on double‐gaussian distributed activation energy model

et al. 2019

Self Cite

View full text Add to dashboard Cite

Pyrolysis is an important technology in the utilization of low-rank coals (LRCs) and is a prerequisite stage for other conversion methods. This study aimed to develop an understanding of the pyrolysis process of LRCs, especially the relationship between the pyrolysis kinetics and the internal chemical structure. The chemical structure parameters of all of the samples were obtained using the Fourier transform infrared spectroscopy (FTIR) method. Thermogravimetric (TG) experiments were conducted at different heating rates (5, 10, and 20 K/min), and the experimental results were fitted using the distributed activation energy model (DAEM). DAEM based on double-Gaussian distribution (2G-DAEM) exhibited an acceptable fit to the experimental data in this study. An analysis of the chemical structure parameters of the four types of coals and the kinetic model obtained by fitting indicated that the difference in the chemical structure parameters among the coal samples could effectively explain the difference in the pyrolysis process and the activation energy distribution. The primary pyrolysis stage of the coal samples, including the thermal hysteresis effect caused by the increase in the heating rate, was accurately described by the 2G-DAEM in this study.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Pyrolysis characteristics of low‐rank coals based on double‐gaussian distributed activation energy model

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…For each sample, 32 scans would be conducted at a resolution of 4 cm −1 with the region from 4000 to 400 cm −1 . The KBr pellets were prepared by mixing and pressing coal (about 1 mg) and KBr at the ratio of 1:100 …”

Section: Methodsmentioning

confidence: 99%

“…Staged conversion can enable the use of coal for the production of synthetic fuels and chemical raw materials based on the resource properties of coal. The staged conversion of coal can largely replace natural gas and petroleum, achieve good economic benefits, and reduce the discharge of pollutants . Pyrolysis is a basic technology for coal thermal processing and a prerequisite step for the subsequent processes.…”

Section: Introductionmentioning

confidence: 99%

Effect of carbonization temperature on the grindability of carbonaceous material produced from different coals

et al. 2019

Self Cite

View full text Add to dashboard Cite

Carbonization experiments were conducted on four kinds of sub-bituminous coal particles at a temperature range of 450-1200°C. The effect of treating temperature on the grindability of produced carbonaceous materials was investigated, and its mechanism was analyzed through various means. Results show that the grindability of all coals, whether caking or slightly-caking, exhibit the same variation trend with an increase in carbonization temperature. Moreover, the entire process can be divided into four stages. (1) After the most intense devolatilization stage, the grindability of carbonaceous material exhibited different degrees of increase compared with that of raw coal because of the development of a pore structure. (2) The first significant decrease in the grindability occurred from the plastic stage to the complete resolidification of the coal matrix.(3) After the aromatic polycondensation stage accompanied by a large amount of H 2 release, the coal molecular structure became compact, such that the grindability of semi-coke considerably decreased again. (4) At high temperatures, the coal matrix underwent graphitization, which changed semi-coke to coke. The molecular structure of coal became ordered, and the grindability decreased again. The analysis shows that a change in the internal chemical structure of carbonaceous material has a much more pronounced effect on grindability than a change in its pore structure, except in the first stage. The constant compaction and regularization of the coal molecular structure continued happening throughout the entire process and play a decisive role in the change in grindability.

show abstract

“…In recent years, significant research has focused on upgrading technologies for lignite to improve the quality of coal and obtain a more economical and safe utilization of lignite. ere are many lignite upgrading methods [1][2][3], but the basic technology can be divided into two processes: dehydration and pyrolysis. Nowadays, dehydration is a basic technology, while pyrolysis is a promising approach in the future.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Micron‐Scale Pore Structure and Connectivity of Lignite during Pyrolysis

Meng

Zhao

Kang

et al. 2020

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

Based on the high-precision microcomputed tomography (micro-CT) technology, the evolution of the μm-scale pore structure and connectivity of lignite during pyrolysis from room temperature to 600°C was studied. The results show that the pore connectivity of lignite increases with the increase of temperature, and the change of pore structure can be divided into four stages: the first stage is from room temperature to 100°C, characterized by generation and connection of small-diameter pores. The second stage is 100–200°C, characterized by rapid expansion and interconnection of pores due to the thermal cracking. The third stage is from 200°C to 450°C, characterized by the slow evolution of pore structure for pyrolysis. The fourth stage is from 450°C to 600°C, characterized by pore interconnection for pyrolysis. 200°C is the temperature at which the μm-scale pore structure of lignite changes dramatically. During the whole pyrolysis process from room temperature to 600°C, the pore quantity of lignite is mainly from the pores of a diameter of 0.65–3 μm. At 200°C and above, the pore volume of lignite is mainly from the pores with a diameter larger than 100 μm, but they are few. These research results have important theoretical reference values for the upgrading and pyrolysis of lignite.

show abstract

Changes in the physicochemical characteristics and spontaneous combustion propensity of Ximeng lignite after hydrothermal dewatering

Cited by 17 publications

References 40 publications

Pyrolysis characteristics of low‐rank coals based on double‐gaussian distributed activation energy model

Pyrolysis characteristics of low‐rank coals based on double‐gaussian distributed activation energy model

Effect of carbonization temperature on the grindability of carbonaceous material produced from different coals

Evolution of Micron‐Scale Pore Structure and Connectivity of Lignite during Pyrolysis

Contact Info

Product

Resources

About