International Journal of Coal Preparation and Utilization
·
2019
·
IF 2.02
Zechen Liu,Yinfei Liao,Yongtian Wang,Maoyan An,Qingteng Lai
Low-rank coals are difficult to float using common hydrocarbon oily collectors, such as dodecane and diesel. In this investigation, a mixture of dodecane and n-valeric acid was used as a collector to enhance low-rank coal flotation. The changes in the induction time and surface functional groups of low-rank coal were measured before and after different collector’s adsorption to indicate its absorption mechanism. The surface free energy was calculated to identify the interaction mechanism quantitatively between coal and collectors. The results showed that the flotation performance using the mixture as a collector was much better than that using dodecane or n-valeric acid solely. The induction time of coal conditioned with the mixed collector was the shortest, which meant the better hydrophobicity and floatability. When used the mixture as collector, the polar group of the n-valeric acid interacting with the oxygenated functional group on the coal surface by hydrogen bond while dodecane primarily covers the hydrophobic sites on the coal surface. Additionally, the mixed collector can minimize the surface free energy of raw coal, the dodecane primarily reduces the nonpolar part of the coal surface free energy while the n-valeric acid reduces the polar part of the coal surface free energy.
研究领域:
矿物加工工程
·
化学工程
✓ 已验证
DOI
高影响因子
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
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Meilu Hao,Peng Liang,Miaomiao Tian,Songze Li,Yue Gao,Yaqing Zhang,Xizhuang Qin,Wenrui Zhang,Tiantian Jiao
To efficiently utilize the oxygenated structures in lignite and obtain value-added oxygenated compounds, this study proposes a low carbon cascading utilization of Zhaotong lignite (ZT) through thermal dissolution and pyrolysis. The selectivity of ethanol (ET), tetrahydrofuran (THF) and ethyl acetate (EA) for oxygenated compounds in thermal dissolution, and the enrichment of thermal dissolution-pyrolysis on oil phases were investigated. The results show that sequential thermal dissolution is selective for different oxygenated compounds in ZT. ET shows selectivity for esters at 350 °C-2 MPa and for phenols at 350 °C-6 MPa. THF and EA are selective for naphthols and esters at 350 °C-6 MPa, respectively. Compared with the single process of thermal dissolution or pyrolysis, thermal dissolution-pyrolysis can significantly increase the oil phases yield with high value-added, in which ET, THF and EA increase the oil phase yields by 24.81 wt%, 13.66 wt% and 7.90 wt%, respectively. In particular, 59.15 wt% of the oxygen is distributed in light oil, and 9.79 % phenols as well as 1.56 % esters are enriched into light oil during thermal dissolution-pyrolysis process of ET. High value-added oxygenated compounds can be selectively enriched by appropriate solvents, at the same time, the quality of pyrolysis tar can be improved and the carbon emissions could be reduced.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
Processes
·
2021
·Vol. 9
·期 3
·404
·
IF 2.847
Maoyan An,Yinfei Liao,Yijun Cao,Xiaodong Hao,Longfei Ma
The mixed collector can improve low rank coal flotation efficiency, but its synergistic mechanism needs to be further explored. In this paper, oleic acid-dodecane (OA-D), oleic acid (OA), and dodecane (D) were employed to treat the low rank coal for revealing new synergistic mechanism of the mixed collector. First the surface free energy of the coal, the surface free energy of coal-water and coal-water-coal were calculated. Then wetting heat measurement, X-ray Photoelectron Spectroscopy (XPS) and FTIR were used to analyze synergistic mechanism of the mixed collector in depth. The results showed that OA-D obtained a higher combustible recovery than using OA and D, respectively. The essence of synergetic mechanism of OA-D was that they formed a relatively ordered “supramolecular structure” on the low rank coal surface, especially there were hydrophobic and van der Waals forces between the oleic acid chain and the dodecane chain that can promote the formation of a continuous collector film.Keywords:low rank coal;mixed collector;synergetic mechanism;supramolecular structure
研究领域:
矿物加工工程
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2023
·
IF 2.2
Lun Du,Guanghua Zhang,Shining Hu,Jie Luo,Wanbin Zhang,Ce Zhang,Junguo Li,Junfeng Zhu
The hydrophilic surface and developed pore structure restricted the application of abundant low rank coals (LRC) for the preparation of coal water slurry (CWS) with high concentration. In this work, emulsified asphalt was applied as an effective and low cost modifier to modify coal surface and improve the slurry making performance of LRC. The successful modification was verified by various technologies, such as chemical titration, X-ray photoelectron spectroscopy (XPS) and Zeta potential measurements. The results revealed that the oxygen containing groups located at LRC surface were covered by emulsified asphalt, which further caused the decrease of Zeta potential. The influence of modification on wettability of coal was also evaluated by contact angle and moisture re-adsorption. It showed that the hydrophobicity of LRC significantly increased, which is accompanied with the reduction of inherent moisture. Besides, the results of nitrogen adsorption and scanning electron microscope (SEM) verified that the hydrophobic layer formed by emulsified asphalt blocked the pores of LRC. The modified LRC also exhibited better adsorption ability to the widely used anionic dispersant naphthalene sulfonate formaldehyde condensate (NSF) than that of raw coal (RC) and microwave dehydration coal (MDC). Anyhow, modified LRC possessed the characteristics as high rank coal. Afterwards, modified coal was applied to prepare CWS. The results showed that CWS prepared by modified LRC exhibited superior slurry making performance as compared to RC and MDC. The surface modification reduced the inherent moisture and promoted the adsorption of dispersant, which increased the free water amount and enhanced electrostatic repulsion and steric hindrance among coal particles. Accordingly, the maximum concentration for CWS increased, and the static stability enhanced.
研究领域:
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Xiaofang You,Wenqi Zhang,Xiaoteng Li,Chuandong Ma,Zhisen Li,Qingbiao Wang,Zhenhua Wang,Lin Li
In this study, alkali-modified municipal sludge (AS) was mixed with low-rank coal to prepare AS-coal water slurry (ASCWS). The influence of AS on the slurrying performance of coal water slurry (CWS) was investigated, and the slurrying mechanism of municipal sludge-CWS (SCWS) was elucidated. Research on the alkali modification of municipal sludge showed that the effectiveness of the modifiers was in the order Ca(OH) 2 > NaOH > KOH > K 2 CO 3 . Considering the apparent viscosity of the slurry as the evaluation criterion, the optimal alkali modification scheme was determined through the response surface optimization test, and 19.99 % Ca(OH) 2 was suitable to modify the sludge for 14.61 h Compared with the unmodified sludge, the content of oxygen-containing functional groups on the surface of AS was reduced, and the flocculent structure was disrupted, which helped improve the slurry formation performance of the SCWS. Blending the sludge with the CWS enhanced the stability of the slurry, and the water separation rates for the SCWS and ASCWS decreased from 18.62 % to 5.00 % and 5.26 %, respectively. The mechanism study showed that the zeta potential values of SCWS and ASCWS decreased from −10.67 mV to –32.23 mV and −39.22 mV, respectively. The increased electronegativity of the slurry owing to the addition of sludge facilitated particle dispersion and enhanced slurry stability. The adsorption patterns of sodium poly[(naphthaleneformaldehyde)sulfonate] (MF) on coal, sludge, and modified sludge were consistent with the Langmuir adsorption model. The pseudo-second-order kinetic model accurately described the adsorption process of MF on coal, sludge, and modified sludge.
研究领域:
能源科学
·
环境工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2014
·
IF 3.019
Jie Zhang,Xingjun Wang,Fuchen Wang,Jie Wang
The hydrogasification of three low rank coals (YX lignite, XD lignite and ZD subbituminous coal) was carried out in a fixed-bed reactor to investigate the effects of hydrogen pressure on the formations of gaseous, liquid and char products. The reactor was typically heated at a rate of 15 °C/min up to 700 °C with a holding time of 60 min under various hydrogen pressures up to 5 MPa. The yields of BTX (i.e., benzene, toluene, and xylene) and naphthalene increased with increasing hydrogen pressure up to 5 MPa for all three coals, but more significant for XD and ZD coals. The compositional analysis of char revealed that the chars produced by the hydrogasification had higher molar ratios of H/C and lower molar ratios of N/C than those produced by the pyrolysis in N 2 atmosphere, whereas the former chars had higher or lower molar ratios of S/C than the latter chars from case to case depending principally on coals. The apparent reaction rate constants of the chars hydrogasification in the isothermal stage as a function of hydrogen pressure were found to follow a power equation of the power exponents varying with coals.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Zhe Yang,Yinfei Liao,Hourui Ren,Xiaodong Hao,Xingwei Song,Zechen Liu
Waste motor oil (WMO) is a hazardous oil pollutant in the automobile industry and low-rank coal slime (LRCS) is a solid waste produced during coal preparation. This paper introduces a comprehensive utilization scheme for these two waste resources through froth flotation . Fourier Transform Infrared Spectroscopy (FTIR) measurement showed that WMO contains hydrocarbons and their oxides (alkane, aromatic derives, ester or carboxylic acid). When acting as a collector for the flotation of LRCS, WMO resulted in a cleaned coal yield of 77.29% and an ash content of 8.97% at the dosage of 5 kg/t, which was a significant improvement over the traditional collector, diesel oil. A novel co-treatment scheme for WMO and LRCS was proposed and discussed. The co-treatment scheme can bring high quality products for the coal preparation plant and give an alternative of disposing the WMO. The traditional WMO disposal methods like WMO regeneration may produce secondary pollution while the co-treatment scheme has little and controllable environmental impact. What’s more, the scheme has better economic benefit than LRCS flotation using diesel oil or the WMO traditional disposal method.
研究领域:
能源与资源工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2022
·
IF 4.132
Maoyan An,Yinfei Liao,Zhe Yang,Yijun Cao,Xiaodong Hao,Xingwei Song,Hourui Ren,Aosheng Yang,Luojian Chen
It has been generally proved that mixed collectors can enhance the flotation of low-rank coal (LRC). However, the inhibition effect of mixed collectors on the detachment between particles and bubbles is still unclear. In this paper, the energy feature of air bubble detachment from the LRC surface in the presence of dodecane (D), oleic acid (OA), and the mixture of dodecane and oleic acid (OA–D) was studied. The effect of collectors on the LRC surface property was analyzed using contact angle measurement, X-ray photoelectron spectroscopy, and wetting heat measurement. The force and displacement during the detachment process were measured synchronously using microforce balance. The results showed that the collector treatment increased the C–C/C–H content and decreased the content of oxygen-containing groups on the LRC surface. The synergistic effect between OA and D enabled the mixed collector to exhibit higher contact angle and wetting heat. Bubble detachment from the LRC surface can be divided into two stages: bubble stretching and bubble sliding, which corresponded to activation energy and detachment work, respectively. The activation energy and detachment work decreased in the same order of OA–D > OA > D, indicating that the mixed collector OA–D increased the energy of bubble detachment from the LRC surface and enhanced the adhesion strength. The theoretical detachment work was calculated, and the calculated results were in agreement with the measured results. This research provides a new perspective on the mechanism of LRC flotation being improved by mixed collectors.
研究领域:
矿物加工工程
·
界面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2016
·
IF 2.75
Yi Li,Muhammad Nadeem Amin,Xingmei Lu,Chunshan Li,Fuqiang Ren,Suojiang Zhang
The catalyst NiO/MgO–Al 2 O 3 was prepared by loading magnesium and nickel onto the surface of γ-Al 2 O 3 beads, respectively, and was adapted to in situ upgrade the high temperature pyrolysis vapor derived from coal pyrolysis. The catalyst synthesis process, and structural variation were characterized by the XRD, SEM, and physical adsorption analyzer. In order to examine the catalytic effect on the different nickel loading ratio in the catalysts, the solid–liquid–gas product distribution, variation of gas and components of coal tar were studied by simulated distillation, GC/MS, elemental analysis and so on. The results shows both the tar yield and the content of the light fraction in the tar can be increased by catalytic up grade. The catalyst has a strong ability to convert the heavy component and polycyclic aromatic hydrocarbons in the tar to lower molecular weight components.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Wei Feng,Mo Zheng,Lijun Jin,Jin Bai,Lingxue Kong,Huaizhu Li,Zongqing Bai,Wen Li
Co-pyrolysis of waste plastics and low-rank coal is a promising approach to deal with the serious waste crisis and improve the clean utilization of low-rank coal. In this work, the comprehensive co-pyrolysis behaviors of low-rank coal and polyethylene plastics were explored systematically by combining TG experiment, in-situ Py-TOF-MS technique, and ReaxFF MD simulation. The consistent results were obtained among three approaches to demonstrate the positive interaction exists between coal and PE during the co-pyrolysis process, which leads to volatile yield increasing with PE addition. TG experimental results showed that the blending ratio of 7:3 for coal and PE has the strongest synergy during the co-pyrolysis process, while Py-TOF-MS experimental results unraveled that the synergistic effect of coal and PE was determined by changing the content of pyrolysis products rather than by producing cross-reaction products. The PE addition significantly reduced the yield of MAHs and normal alkyl-substituted monophenols and increased the yield of olefins, alkanes, and aromatic derivatives. ReaxFF MD simulation results complement the experimental observation to obtain similar weight loss profiles with TG experiments and consistent identification of major representative tar pyrolyzates with Py-TOF-MS experiments. Particularly, the detailed gas evolving trends and the underlying bond-breaking reactions of C C, C O, and C H bonds were revealed by ReaxFF MD, which indicates PE addition promotes bond breaking of C C and C H to enhance more tar generation. The combination of experiments and ReaxFF MD simulations can capture the comprehension of the co-pyrolysis process between low-rank coal and PE, which can be extended to other co-pyrolysis applications for related solid fuels.
研究领域:
能源与燃料化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Yinfei Liao,Hourui Ren,Maoyan An,Yijun Cao,Zhe Yang,Xiaodong Hao,Xingwei Song
It is well known that mixed collectors can effectively strengthen the flotation of low-rank coal. However, less concern has been paid to the detachment of low-rank coal flotation using mixed collectors. In this study, the force of air bubble detachment from low-rank coal surface treated by oleic acid (OA), dodecane (D), and oleic acid–dodecane (OA–D) collector mixture was investigated using microforce balance. The results showed that the process of bubble detachment from the low-rank coal surface was divided into three stages: relaxation stage, stretching stage, and sliding stage. The equilibrium contact angle and critical contact angle were the transition points between different stages. The order of detachment force required for bubble detachment from the surface of low-rank coal was OA–D > OA > D, indicating a synergistic effect between OA and D. Based on the three parameters of equilibrium contact angle, critical contact angle, and contact line length, a theoretical model was proposed to calculate the detachment force. The calculated results were in agreement with the measured results.
研究领域:
矿物加工工程
·
界面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）