Preparation and
            <i>optimization</i>
            of thermosensitive hydrogels for inhibiting coal oxidation

Guo, Shengli; Yuan, Shujie; Geng, Weile; Dong, Ziwen

doi:10.1002/er.6362

Cited by 18 publications

(8 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…34 With the increase of treatment temperature, the band intensities at 2915 and 2850 cm À1 (CH 2 , CH 3 asymmetrical stretching vibration) decrease, apparently, compared with raw coal, which suggests that more soluble constituents were extracted at higher temperatures. 35 Due to dewatering of ZDC during thermal treatment, the band intensity of OH ranging from 3300 to 3700 cm À1 for all treated coals is considerably weak.…”

Section: Gas Release and Functional Group Changesmentioning

confidence: 95%

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Han

2021

Intl J of Energy Research

View full text Add to dashboard Cite

Sodium-rich coals are suitable raw materials for direct coal liquefaction (DCL).However, sodium species in coals, especially exchangeable ones, can significantly reduce oil yield. In this work, to increase oil yield in direct liquefaction of sodium-rich coals, a feasible method using organic solvents to pretreat sodium-rich coals is proposed. Initially, sodium-rich coal was thermally treated with tetralin or 1-methylnaphtalene. Then, raw coal and all the treated coals were liquefied under the same conditions to evaluate the effects of thermal treatment on structural changes of coal molecules and oil yield. The results show that surface areas of the treated coals increased to 7.86 m 2 /g at most, which was favorable for combination between hydrogen and coal molecules during the DCL process. More importantly, the content of hydrogen in the treated coals was 0.95 wt% higher than that of raw coal on average, suggesting that treated coals could be later liquefied at mild conditions. Raman spectra demonstrated that during thermal treatment with tetralin, small aromatic ring systems in raw coal were prehydrogenated and transformed into nonaromatic systems. The pre-hydrogenation of the coal matrix definitely contributes to the increase in oil yield. In view of sodium species distribution in the treated coals, it is proved that tetralin can promote the transformation of exchangeable sodium species into other chemical forms more easily than 1-methylnaphtalene, which implies that tetralin has more positive effects on the increase of oil yield. Compared with that of raw coal, oil yields in direct liquefaction of the samples treated by tetralin increase by 14.0 to 15.1 wt% (daf).

show abstract

Section: Gas Release and Functional Group Changesmentioning

confidence: 95%

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Han

2021

Intl J of Energy Research

View full text Add to dashboard Cite

show abstract

“…Cheng et al prepared a new type of smart gel for mining, which could effectively utilize corn stalks, contained expandable graphite that responded rapidly to temperature, and had good thermal stability and fire extinguishing properties . Guo et al physically cross-linked an MC-PEG-SDS ternary thermosensitive hydrogel, characterized its properties, and found that it could effectively suppress coal oxidation . Tsai et al prepared five coal spontaneous combustion inhibitors such as P(NIPA-co-SA) thermosensitive hydrogel and compared their comprehensive properties by FTIR, TG, and other characterization methods .…”

Section: Introductionmentioning

confidence: 99%

Mining Polyethylene Glycol-Based Thermosensitive Hydrogel Materials: Preparation and Flame Retardant Properties

et al. 2023

View full text Add to dashboard Cite

A new type of efficient and anti-extinguishing materials to inhibit coal spontaneous combustion is required because of the current situation of the short activity cycle of existing anti-extinguishing technology. Now, polyethylene glycol (PEG) was used as a water-absorbing monomer to polymerize various substances to prepare an AB-type mining thermosensitive hydrogel that was obviously thermoresponsive. The thermosensitive hydrogel, which is low-cost and stable, can be stored for a long time, and it is prepared by compounding A and B components. The orthogonal experiments determined the optimal ratio of component A, while the controlling variable experiments determined the optimal ratio of component B. The thermal stability and flame-retardant properties of the AB-type thermosensitive hydrogel were analyzed during the process of natural oxidation of coal, and the temperature responsiveness of thermosensitive hydrogels was investigated at different temperatures. The results showed that the optimal ratio of polyethylene glycol:methyl cellulose:sodium carboxymethyl cellulose:guar gum of component A was 6:6:1.2:1.5; and the ratio of bentonite:kaolin:Mg(OH)2 of component B was 2:1:1. When the ratio of component A to component B was 1:2, the AB-type thermosensitive hydrogel shows the best flame retardant properties. When this ratio of gel was applied to coal samples, the weight loss was just 6%, and the reduction of CO was as high as 72.6%. The gel, which was convenient for transportation in mining pipelines, had strong fluidity at low temperatures and rapid temperature response. As the temperature rose, a phase transition occurred gradually, and after the phase transition, a high-viscosity solid substance was formed, whose viscosity was approximately 11 times that of the room temperature. It plugged the pores effectively, and in the high-temperature region, the occurred phase transition gathered to extinguish the fire. It is a new type of high-efficiency anti-extinguishing material with excellent properties.

show abstract

“… 34 Therefore, it is insufficient to use noncoal reference samples in the experiments of low-rank coal, especially for high-moisture-content coal. 35 , 36 …”

Section: Introductionmentioning

confidence: 99%

“…The change of the structure will significantly change the spontaneous combustion characteristics of coal. − With the decrease in the particle size, the moisture content, the heat of wetting release, and the risk of spontaneous combustion increase . Therefore, it is insufficient to use noncoal reference samples in the experiments of low-rank coal, especially for high-moisture-content coal. , …”

Section: Introductionmentioning

confidence: 99%

“…34 Therefore, it is insufficient to use noncoal reference samples in the experiments of lowrank coal, especially for high-moisture-content coal. 35,36 The existing experimental methods can reflect the process of coal spontaneous combustion to a certain extent and have a higher theoretical value, but they also have several shortcomings. The experimental process of a large-scale test bench is more complex and yields low precision and poor repeatability.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Rapid Contrastive Experimental Study on the Adiabatic Spontaneous Combustion Period of Loose Lignite

et al. 2021

Self Cite

View full text Add to dashboard Cite

The adiabatic spontaneous combustion period of coal is an important index for the macroscopic characterization of coal spontaneous combustion, and it is affected by many internal and external factors. There are several methods to study it, but there are various shortcomings to these methods. Some require too much time, while others have too many interfering factors. To quickly obtain the accurate adiabatic spontaneous combustion period of coal, a rapid contrastive experimental method was designed. In this method, the coal samples of the experimental and control groups were the same, and air and nitrogen were used as control atmospheres. A theoretical calculation method for the adiabatic spontaneous combustion period based on this method is proposed. The experimental results showed that during the temperature-programmed coal spontaneous combustion experiment, the increase in the coal temperature was due to physical and chemical heating. Physical heating is the heating effect of the temperature-programmed furnace body and the heated gas on the coal sample. Chemical heating includes oxidative exothermic heating promoted by physical and adiabatic oxidation heating. The adiabatic oxidative heat release can be determined by the oxidation heat release in the air atmosphere minus the oxidation heat release corresponding to the coal sample temperature in the nitrogen environment at the same period. The adiabatic spontaneous combustion period of coal can be calculated from the adiabatic oxidation heat release. Our results provide a rapid contrastive experimental method to quickly obtain the accurate adiabatic spontaneous combustion period of coal.

show abstract

Preparation and optimization of thermosensitive hydrogels for inhibiting coal oxidation

Cited by 18 publications

References 44 publications

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Mining Polyethylene Glycol-Based Thermosensitive Hydrogel Materials: Preparation and Flame Retardant Properties

Rapid Contrastive Experimental Study on the Adiabatic Spontaneous Combustion Period of Loose Lignite

Contact Info

Product

Resources

About