ADVANCED POWDER TECHNOLOGY
·
2024
·
IF 4.2
Wenqi Zhang,Chuandong Ma,Zhisen Li,Meng He,Qingbiao Wang,Lin Li,Xiaofang You
In this study, modified low rank coal water slurry (M-LRCWS) was prepared by using diesel modified low rank coal (LRC) and compared with low LRC water slurry (LRCWS) to investigate the slurry formation mechanism and combustion characteristics of coal water slurry. Meanwhile, the combustion kinetics of coal-water slurry was investigated using kinetic methods to probe the combustion reaction mechanism. The results showed that the slurry formation concentration of LRC was 70 %, while the slurry formation concentration of M-LRCWS was 72 %, which was an increase of 2 %. The diesel modification positively affected the stability of CWS. The comprehensive combustion characteristics index of the same slurry deteriorated with increasing heating rate. At the same heating rate, M-LRCWS has better combined combustion performance, higher flammability and more stable ignition performance. Combustion kinetics calculations showed that the reaction activation energies were 105.50 kJ/mol for M-LRCWS and 99.59 kJ/mol for LRCWS using the FWO method, and 93.48 kJ/mol for M-LRCWS and 92.68 kJ/mol for LRCWS using the Starink method. The activation energy of M-LRCWS is slightly higher than that of LRCWS, which indicates that the diesel fuel is encapsulated in the coal particles and it is difficult to activate the substance. As a result, the dispersion system is more stable and favorable for storage and transportation. The physical functions of LRCWS and M-LRCWS were calculated using the Achar differential equation and the Coats-Redfern integral equation, and the results showed that both LRCWS and M-LRCWS followed the tertiary reaction (F3) mechanism.
研究领域:
能源科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2024
·
IF 5.3
Chuandong Ma,Wenqi Zhang,Zhisen Li,Jida Niu,Qingbiao Wang,Zhenhua Wang,Lin Li,Xiaofang You
In this study, the slurry formation properties and multi-phase dispersion mechanism of hydrocarbon modified low-rank coal (LRC) were explored by combining experiments and simulations, aiming to provide some theoretical guidance for the slurrying of surface-modified LRC. The experimental results revealed that compared with the LRC water slurry (LRCWS), the consistency of the diesel modified low-rank coal water slurry (M−LRCWS) is decreased, the pseudo plasticity is enhanced, and the constant viscosity concentration is increased by 1.89 %. The results of XPS analysis indicated that the surface C/O of M−LRC increases from 5.67 (LRC) to 6.83, and the content of oxygen-containing groups decreases by 3.10 %, indicating that the surface non-polarity is enhanced. In molecular dynamics simulation, compared with the two dispersed systems of COAL/ Sodium poly[(naphthaleneformaldehyde) sulfonate] (MF)/H 2 O (CMW) and COAL/ Dodecane (DD)/MF/H 2 O (CDMW), the E bin of water molecules in both of systems is negative, indicating that water molecules are easy to combine with the coal surface. The absolute E bin of the CDMW system is 2612.56 kcal/mol lower than that of CMW. The adsorption force of coal molecules to water molecules is weakened, which leads to a decrease in the content of water molecules adsorbed on coal. The results show that the surface hydrophobicity of LRC modified by DD is enhanced, so the proportion of free water in the system increases, which is beneficial to increase the concentration of coal water slurry. The simulation results confirm the experimental results.
研究领域:
能源科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2022
·Vol. 17
·期 6
·e2837
·
IF 1.777
Huijun Wu,Dongmei Lv,Yunhao Nie,Tingao Jiang,Jing Li,Shuwen Gong,Hui Yan
The disadvantages of low-rank coal in the preparation of coal water slurry (CWS) are well known, but the synthesis of suitable dispersants is a promising solution. Polycarboxylate dispersant (PC) is expected to be an efficient CWS dispersant due to its flexible and controllable structure. In this study, a series of binary PC dispersants were synthesized by controlling the ratio of acrylic acid (AA) to sodium styrene sulfonate (SSS), initiator fraction, and temperature, and the optimal PC was selected based on the apparent viscosity of 72 # CWS at 100 s −1 . The properties of 72 # CWS were studied: This CWS exhibited shear-thinning behavior, >14 static stability, and >55 wt% maximum solid loading, indicating the satisfactory performance of the optimal PC. The experimental results (including adsorption tests and zeta potential measurement) and molecular dynamics simulation showed that PC was effectively adsorbed on the surface of the coal particles by a horizontal multipoint adsorption mode, mainly through the interaction between the hydrophobic groups of the PC molecule and the hydrophobic areas of the coal particles. The hydrophilicity of the coal particles was therefore improved and the stability of their hydration layer was also enhanced, which accounted for the good static stability of 72 # CWS. The amount of PC adsorption and the improved absolute zeta potential were associated with the decent properties of 72 # CWS. This study is significant for promoting the molecular design of CWS dispersants based on their adsorption behavior.
研究领域:
化学工程
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能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Taotao Sun,Wenlin Shuai,Shiwei Wang,Hongfeng Yin,Yiming Li,Jie Zhang,Xuemin Yuan,Xiaolong Yu
Coal water slurry (CWS) modified with traditional linear naphthalene sulfonate formaldehyde (NSF) polymers exhibited limited stability in long-haul pipeline transportation, because of low steric hindrance energy (V S ) between coal particles. To study the effect of structural modification of dispersant on the V S value, a branched multi-arm poly(sodium acryloyloxy-2-naphthalenesulfonate) (Ma-PANS) dispersant was synthesized by controlled/living radical polymerization (CRP), using vinyl monomer sodium acryloyloxy-2-naphthalenesulfonate (ANS) with triple functional groups as precursor. The making-slurry experiment results showed that the viscosity of Yulin CWS modified with Ma-PANS dropped 319 mPa·s, and its stability was remained at 100% after 30 days. The effects of the structural modification on adsorption amount, adsorption parameters and adsorption conformation were also analyzed by adsorption experiments and molecular dynamics (MD) simulations. The results showed that the specific conformation of Ma-PANS contributed to improving adsorption parameters. This reduced the diffusion rate of dispersant on coal surface, resulting in enhanced stability of slurry. Moreover, the numerical calculation results based on the extended Derjaguin-Landau-Verwey-Overbeek theory (eDLVO) showed that the enhancements on dispersion and stability were attributed to the structure of dispersant being changed from linear to multi-arm. The unique multi-arm structure brought significant increase in the V S value when impeding the approach among particles and disrupting flocculation, thus effectively enhanced dispersion and stability of CWS.
研究领域:
材料科学
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高分子化学
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胶体与界面科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）