Study on the Effect and Mechanism of Water Immersion on the Characteristic Temperature during Coal Low-Temperature Oxidation

Zhai, Xiaowei; Song, Bobo; Wang, Bo; Ma, Teng; Ge, Hui

doi:10.1007/s11053-021-09854-0

Cited by 30 publications

(5 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The adsorption curves rise slowly at the relative pressure ( P / P 0 ) 0 < P / P 0 < 0.5, which is due to the single-layer N 2 adsorption. The adsorption curves at 0.5 < P / P 0 < 0.85 gradually increase, which is considered as the conversion of N 2 from single-layer adsorption to multilayer adsorption. , The adsorption curve rises sharply at 0.85 < P / P 0 < 1, indicating capillary condensation. , The N 2 adsorption volume at relative pressure near 1.0 increases significantly compared with that of the raw coal samples, which reflects the increase of mesopore quantity after CS 2 extraction.…”

Section: Resultsmentioning

confidence: 94%

See 1 more Smart Citation

Effects of CS₂ Solvent Extraction on Nanopores in Coal

Si,

Liu,

Lin

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

This study investigates the effects of the carbon disulfide (CS2) extraction on nanopores of the anthracite samples. Comprehensive pore measurement techniques, including high-pressure mercury intrusion (HPMI), low-temperature nitrogen adsorption (LTNA), and low-temperature CO2 adsorption (LTCA), were employed to analyze the variations of nanopore structure and fractal characteristics. After CS2 extraction, the macropore average diameter and volume increase, while the macropore area and fractal dimension decrease, indicating the pore-enlarged and fractal dimension-reduced effects of CS2 extraction on macropores. The pore-generated and fractal dimension-increased effects of CS2 extraction on mesopores induce reduction in the average diameter and an increase in mesopore volume, area, and fractal dimension. The pore-enlarged and fractal dimension-reduced effects of CS2 extraction on micropores cause an increase in the average diameter and reduction in micropore volume, area, and fractal dimension. These effects of CS2 extraction on nanopore structure are conducive to enhancing CBM transport. This study can provide a theoretical basis on the chemical reservoir stimulation technique with CS2 extraction.

show abstract

Section: Resultsmentioning

confidence: 94%

“…55,56 The adsorption curve rises sharply at 0.85 < P/P 0 < 1, indicating capillary condensation. 57,58 The N 2 adsorption volume at relative pressure near 1.0 increases significantly compared with that of the raw coal samples, which reflects the increase of mesopore quantity after CS 2 extraction.…”

Section: Effect Of Cs 2 Extraction On Mesoporesmentioning

confidence: 96%

Effects of CS₂ Solvent Extraction on Nanopores in Coal

Si,

Liu,

Lin

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…Because, oxidation treatment mainly affects the pore structure (coal-oxygen contact area and space) and the number of active radicals of WS coal; OC mainly affects the number of coal-oxygen active contacts (number of radical oxidation reactions) of WS coal. PWC possesses a complex surface pore structure and abundant active radicals (Zhai et al 2021), its number of active collisions in a higher concentration of oxygen atmosphere increases dramatically, and the number of sites where oxidative heat production occurs increases significantly, resulting in a significant increase in the risk of SC as a result (diagonal red area in Fig. 13).…”

Section: Discussionmentioning

confidence: 99%

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

Niu,

Yang,

Sun

et al. 2024

Environ Sci Pollut Res

View full text Add to dashboard Cite

In order to study the oxidation characteristics and spontaneous combustion (SC) tendency of pre-oxidized long-term water-soaked coal under different oxygen concentrations, raw long-flame coal (RC), water-soaked 200-day coal (S200), pre-oxidized water-soaked coal at 200 ℃ (O200S200), and preoxidized water-soaked coal at 300 ℃ (O300S200) coals were used for the study. The coal spontaneous combustion(SC) program heating test system was adopted to conduct experimental analyses at 21%, 15%, 10%, 5%, 3% oxygen concentration(OC) for experimental analysis. The results show that pre-oxidation water-soaked treatment(PWT) promotes the coal-oxygen complex reaction and increases the rate of coal oxygen consumption(OCR) and the rate of carbon and oxygen compounds production. The rate of CO and CO2 production of the water-soaked(WS) coal increased by 0.329 mol•(cm 3 •s) -1 and 0.922 mol•(cm 3 •s) -1 , respectively, compared with that of the original coal sample. PWT reduces the activation energy of coal in the low-temperature oxidation stage (the maximum difference can be up to 110.99 KJ/mol) and enhances the oxidizing and heat-releasing capacity. There is a large amount of water in the WS coal, and its cross-point temperature and SC propensity index increased. There was a synergistic effect between the pre-oxidation(PO) and WS treatment, and the lowest comprehensive determination index of the SC propensity of coal in O200S200 samples was 831.92 which was 4.72 lower than that of RC

show abstract

“…17 Conversely, Zhai et al reported that water immersion reduced the specific surface area of coal samples while augmenting their average pore diameter and overall pore volume, facilitating oxygen diffusion and transport. 18 Bu et al compared preoxidized and watersoaked coal samples with raw coal based on SEM, nitrogen adsorption, and other experiments and found that the ratio of mesopores and macropores in the high-temperature-oxidized water-soaked coal sample increased, and the augmentation of coal's oxygen interaction sites fostered its oxidation process. 19 Bu et al found that water-soaked coal samples exhibit a more developed pore structure when oxidized at 300 °C.…”

Section: Introductionmentioning

confidence: 99%

Study on Spontaneous Combustion Characteristics and Microstructure of Bituminous Coal under Water Immersion

Fan,

Li,

Zhang

et al. 2024

ACS Omega

View full text Add to dashboard Cite

The stagnant water above the coal seam flows into the goaf, causing the goaf coal to be soaked by water for a long time. Compared with dry raw coal, water-soaked coal has a stronger tendency for spontaneous combustion, which poses a serious threat to mining operators. To unravel the impact of water immersion on coal's self-heating properties, an investigation was conducted employing techniques such as simultaneous thermogravimetric analysis/differential scanning calorimetry (TG/DSC), scanning electron microscopy (SEM), low-temperature nitrogen adsorption based on the BET theory, and Fourier transform infrared spectroscopy (FTIR). The variations in the characteristic temperature, microphysical structure, and active functional groups of bituminous coal with water immersion degrees of 10, 30, 50, and 100% were studied, and the experimental results showed that (1) during the initial stage of coal self-ignition oxidation, moisture can cause a delay in the characteristic temperature points of bituminous coal. When the degree of water saturation in bituminous coal reaches 100%, both the critical temperature (T 1 ) and the cracking temperature (T 2 ) peak at 48.14 and 205.06 °C, respectively. However, after the water evaporation phase is complete, water soaking promotes the spontaneous combustion of bituminous coal. (2) The number of pores and fractures in bituminous coal is positively correlated with the amount of water soaked, with the average pore diameter increasing from 10.124 nm in raw coal to 15.547 nm in the A 4 coal sample. Moreover, when the degree of water immersion reaches 100%, the proportion of mesopores and macropores increases to 38.89 and 19.95%, respectively. (3) Compared to untreated coal, the number of functional groups in watersoaked coal samples increases. With the increase in water immersion, the hydroxyl (−OH) content of raw coal and four kinds of bituminous coal with different degrees of immersion was 40.8, 41.3, 42, 43.9, and 42.9%, respectively, showing a trend of increasing first and then decreasing. When the degree of water immersion of bituminous coal is 50%, the natural tendency is the strongest. These findings contribute to elucidating the underlying mechanism of water immersion's impact on coal self-ignition, thereby holding significant implications for enhancing fire safety measures in mine working areas.

show abstract

Study on the Effect and Mechanism of Water Immersion on the Characteristic Temperature during Coal Low-Temperature Oxidation

Cited by 30 publications

References 37 publications

Effects of CS₂ Solvent Extraction on Nanopores in Coal

Effects of CS₂ Solvent Extraction on Nanopores in Coal

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

Study on Spontaneous Combustion Characteristics and Microstructure of Bituminous Coal under Water Immersion

Contact Info

Product

Resources

About

Study on the Effect and Mechanism of Water Immersion on the Characteristic Temperature during Coal Low-Temperature Oxidation

Cited by 30 publications

References 37 publications

Effects of CS2 Solvent Extraction on Nanopores in Coal

Effects of CS2 Solvent Extraction on Nanopores in Coal

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments

Study on Spontaneous Combustion Characteristics and Microstructure of Bituminous Coal under Water Immersion

Contact Info

Product

Resources

About

Effects of CS₂ Solvent Extraction on Nanopores in Coal

Effects of CS₂ Solvent Extraction on Nanopores in Coal