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
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产品关联
DOI
高影响因子
ENERGY
·
2022
·
IF 8.857
Jun Zhao,Hassan Nasir Mangi,Zhenyue Zhang,Ru'an Chi,Haochen Zhang,Mengyu Xian,Hong Liu,Haibin Zuo,Guangwei Wang,Zhigao Xu,Ming Wu
This study aimed to effectively utilize low-rank coal and biomass residue in the coking process . The gasification performance of cokes prepared from the modified coal was investigated, meanwhile the structural characteristics of different cokes were analyzed by Raman spectroscopy, X-ray diffraction and infrared spectroscopy. The results showed that solvent thermal extraction process could dramatically remove the ash content and gradually enhance the caking performance and carbon content for low-rank coal. The ash content, carbon content, penetration distance, and caking index of modified coal were 0.86 wt%, 78.18 wt%, 35.48 mm, and 95%, respectively. Structural analysis results showed that the order degree and graphitization degree of BIOC-HPC coke were superior to those of coking coal coke, and the overall compactness of BIOC-HPC coke was improved. Compared with the coking coal coke, the gasification performance of coke could be improved by adding modified coal; the optimal addition ratio of the modified coal in coal blending for coking was between 10 wt% to 15 wt%. The gasification kinetic analysis indicated that the RPM model was the optimal model for simulating the gasification process of modified coal coke, and the activation energy was between 211.36 kJ/mol and 228.81 kJ/mol.
研究领域:
能源科学
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材料科学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2024
·
IF 7.4
Sifei Su,Mudassir Hussain Tahir,Xingxing Cheng,Jiansheng Zhang
Coal gasification technology has led to a significant discharge of solid waste known as coal gasification slag (CGS). However, the high composition of Si and Al in CGS, along with its high carbon content, offers opportunities for potential resource utilization. This review aims to discuss the characterizations, modification methods, and applications of CGS and CGS-based materials for resource utilization. The current study summarizes the compositions, micromorphology , and physicochemical properties of CGS, as well as its modifications and applications in adsorption and other areas. This review shows that modification can change the material's chemical composition and improve its performance. The material has excellent adsorption performance after modification and has the potential to be used in various industries. Although the use of CGS is helpful in addressing the discharge of coal-based solid waste, there is an urgent need for an efficient, practical, and all-encompassing utilization technology. Overall, this review presents a brief vision of CGS's future research and applications.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2023
·
IF 8.7
Bo Lv,Xiaoman Chai,Xiaowei Deng,Feishuo Jiao,Chaojun Fang,Baolin Xing
Recovering inner residual carbon is important for fully utilizing coal gasification fine slag (CGFS) resources. In this study, we adopted a combined gravity-separation and flotation process to efficiently recover residual carbon by considering the characteristics of the CGFS and optimizing the operating factors of the process. CGFS is principally a mixture of residual carbon and ash, with low-density particles containing more of the former. Accordingly, residual carbon is preliminarily enriched by gravity separation, in which gas velocity ( v g ) and water velocity ( v w ) significantly impact separation efficiency, followed by feed volume ( m ). The residual carbon in the initial concentrate was preliminarily enriched (i.e., loss on ignition ( LOI ): 55.90%; combustible recovery ( R o ): 72.36%) under appropriate operating conditions (i.e., v w = 0.04 m/s, v g = 3 m/s, m = 150 g). Moreover, the quality of the flotation concentrate was most influenced by collector dosage ( m c ), followed by aeration rate ( η ), frother dosage ( m f ), stirring speed ( w ), and grinding time ( t ) during flotation of the primary concentrate. The flotation concentrate exhibited LOI and R o values of 90.95% and 50.34%, respectively, under the optimal flotation conditions (i.e., m c = 20 kg/t, m f = 15 kg/t, w = 2600 rad/min, η = 200 L/h, t = 360 s); it has a high residual carbon content and is an ideal raw material for preparing fuels or carbon materials.
研究领域:
矿物加工工程
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资源与环境科学
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产品关联
DOI
PubMed
高影响因子
Frontiers of Chemical Science and Engineering
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2022
·Vol. 16
·期 12
·1689-1699
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IF 4.803
Li Wang,Li Wen-Ying,Wang Xing-Bao,Feng Jie
Radicals are important intermediates in direct coal liquefaction. Certain radicals can cause the cleavage of chemical bonds. At high temperatures, radical fragments can be produced by the splitting of large organic molecules, which can break strong chemical bonds through the induction pyrolysis of radicals. The reaction between the formation and annihilation of coal radical fragments and the effect of hydrogen-donor solvents on the radical fragments are discussed in lignite hydrogenolysis. Using the hydroxyl and ether bonds as indicators, the effects of different radicals on the cleavage of chemical bond were investigated employing density functional theory calculations and lignite hydrogenolysis experiments. Results showed that the adjustment of the coal radical fragments could be made by the addition of hydrogen-donor solvents. Results showed that the transition from coal radical fragment to H radical leads to the variation of product distribution. The synergistic mechanism of hydrogen supply and hydrogenolysis of hydrogen-donor solvent was proposed.
研究领域:
化学工程
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物理化学
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能源科学
✓ 已验证
DOI
高影响因子
Separations
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2025
·Vol. 12
·期 2
·22
·
IF 2.7
Huan-Huan Fan,Xiang-Ling Wang,Jie Feng,Wen-Ying Li
A comprehensive understanding of the compositions and physicochemical properties of coal-based liquids is conducive to the rapid development of multipurpose, high-performance, and high-value functional chemicals. However, because of their complex compositions, coal-based liquids generate two-dimensional gas chromatography (GC × GC) chromatograms that are very complex and very time consuming to analyze. Therefore, the development of a method for accurately and rapidly analyzing chromatograms is crucial for understanding the chemical compositions and structures of coal-based liquids, such as direct coal liquefaction (DCL) oils and coal tar. In this study, DCL oils were distilled and qualitatively analyzed using GC × GC chromatograms. A deep-learning (DL) model was used to identify spectral features in GC × GC chromatograms and predominantly categorize the corresponding DCL oils as aliphatic alkanes, cycloalkanes, mono-, bi-, tri-, and tetracyclic aromatics. Regional labels associated with areas in the GC × GC chromatograms were fed into the mask-region-based convolutional neural network’s (Mask R-CNN’s) algorithm. The Mask R-CNN accurately and rapidly segmented the GC × GC chromatograms into regions representing different compounds, thereby automatically qualitatively classifying the compounds according to their spots in the chromatograms. Results show that the Mask R-CNN model’s accuracy, precision, recall, F1 value, and Intersection over Union (IoU) value were 93.71%, 96.99%, 96.27%, 0.95, and 0.93, respectively. DL is effective for visually comparing GC × GC chromatograms to analyze the compositions of chemical mixtures, accelerating GC × GC chromatogram interpretation and compound characterization and facilitating comparisons of the chemical compositions of multiple coal-based liquids produced in the coal and petroleum industry. Applying DL to analyze chromatograms improves analysis efficiency and provides a new method for analyzing GC × GC chromatograms, which is important for fast and accurate analysis.
研究领域:
化学工程
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人工智能
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2018
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IF 4.908
Fei Wang,Xueming Dong,Xing Fan,Yun-Peng Zhao,Guo-Sheng Li,Chu-Fan Wang,Xian-Yong Wei,Feng-Yun Ma,Mei Zhong
In-source collision activated dissociation (ISCAD) is an effective method to obtain molecular structure of coal and biomass and provide basic knowledge for coal/biomass conversion. Twenty two coal/biomass-based model compounds and one coal extract were studied via ISCAD to understand the relationship between collision energy and molecular structure and the application of ISCAD in the characterization of coal. Model compounds showed different fragmentation patterns with the increase of collision energy and the detailed fragmentation pathways in context of collision energies were proposed. According to the ISCAD results of coal extract, the weighted mean molecular weight (MW) and weighted mean double-bond equivalent (DBE) values of ionized coal molecules decreased over collision energy of 80 eV. The decrease of weighted mean MW and DBE were mainly caused by the cleavage of alkyl chains, bridged bonds, and minor cracking of small aromatic cores from precursor ions upon fragmentation. Therefore, the optimal ISCAD collision energy for the investigation of aromatic core structures of the coal extract should be around 80 eV.
研究领域:
化学
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能源科学
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分析化学
✓ 已验证
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Haojie Liu,Linjing Hao,Guoli Zhou,Daoguang Teng,Peng Li,Yijun Cao,Baolin Xing
Lignite serves as prefer carbon sources for preparation of composite carbon fibers, as the good reactivity of carbon units and good solubility of reaction products. However, low yield of soluble products from lignite at mild condition and high volatility of toxic organic solvent during spinning are not beneficial for the preparation of coal-based composite carbon fiber. In this work, the sodium hydroxide was introduced to enhance the thermal dissolution of lignite with methanol at mild condition. The water-soluble fraction, separated from the thermal dissolution products, was then mixed with certain amount of polyvinyl alcohol to afford a solution. The solution was treated by electrostatic spinning, pre-oxidation, carbonization, acid washing, and activation, ultimately producing the coal-based composite carbon fibers. In these treatment process, acid washing is beneficial for the removal of surface impurities, resulting an increase in the specific surface area and the exposure of active sites on the surface of the composite carbon fibers. The specific capacitance is enhanced from 73.5 F/g to 197.1 F/g at a current density of 1 A/g. The activated coal-based composite carbon fibers were assembled into a symmetric snap capacitor with an energy density of 8.5 Wh/kg at a power density of 250 W/kg. This work explored a new approach for preparation of coal-based composite carbon fibers by electrostatic spinning in aqueous solution system. It is also a value-added and environmentally friendly pathway of carbon fraction from lignite for preparation of supercapacitor electrode materials.
研究领域:
材料科学
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能源工程
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产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Guolan Dou,Chen Wang,Xiaoxing Zhong,Botao Qin
In this study, lignin modified cementitious materials (LFGS) were synthesized to determine the viability of mineral cementitious sealing and firefighting materials using uncalcined coal gangue (UCG) and fly ash (FA) as raw materials in order to realize the resource utilization of coal-based solid waste and prevent spontaneous combustion of coal gangue and coal fires. The 28-d compressive strength was increased to 63 MPa, the fluidity was improved to 142 mm, and the final setting time was shortened to 75 min with 0.1 wt% lignin. Thermal exposure experiments demonstrated that lignin modification could improve the high temperature resistance in terms of residual compressive strength , thermal crack and shrinkage resistance. The microstructure and thermogravimetric characterization of the resulting cementitious materials revealed the generation of a dual-crosslinked network composed of covalent linkages (Si-O-Al bonds) and hydroxyl groups-Ca 2+ coordination bonds. The average air sealing efficiency of LFGS was found to be 53.7% higher than that of ordinary Portland cement slurry. The examination of the CO 2 emissions of the cementitious materials revealed that the carbon emission index of LFGS was approximately 55% lower than that of ordinary Portland cement . This study not only presents a resource utilization strategy for uncalcined coal gangue and coal fly ash, but also a green and low carbon emission cementitious firefighting material to prevent coal fires.
研究领域:
材料科学
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环境科学
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矿业工程
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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
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材料科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2023
·
IF 8.6
Bin Liu,Peng Lv,Ruofei Wu,Yonghui Bai,Jiaofei Wang,Weiguang Su,Xudong Song,Guangsuo Yu
The discharge of large-scale industrial solid waste and wastewater has caused severe damage to environmental health. In this study, the adsorption behaviors of Pb(II) and Congo Red (CR) dye in single and binary aqueous systems were investigated using novel functionalized nanoporous glass microspheres (NGM). The NGM material was fabricated from coal gasification fine slag (CGFS) by a simple treatment and characterized using TG, BET, XRD, TEM, FT-IR, and XPS to analyze its physicochemical properties. The adsorption experiments showed that the adsorption amounts of DMA-NGM for Pb(II) and CR were 302.39 mg/g and 342.74 mg/g for the single systems, and 372.73 mg/g and 412.93 mg/g for the binary systems, respectively. The increased adsorption capacity was attributed to the synergistic effect of electrostatic attraction and chelation. Furthermore, the pseudo-second-order model and Elovich model could reasonably describe the adsorption of Pb(II) and CR on DMA-NGM. Pb(II) adsorption on DMA-NGM was monolayer adsorption and CR adsorption was multilayer adsorption. In summary, the results demonstrate the potential of efficient and environmentally friendly adsorbents for the resource recovery of CGFS and the processing of printing and dyeing wastewater.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2023
·
IF 6.1
Xiao Tian,Lei Zhao
Concentrations of trace elements in coal and coal combustion products are commonly analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) due to large number of elements detected and the relatively the low detection limits of this technique. Like other geological samples, complete dissolution of coal and coal combustion products is also essential for accurate ICP-MS results. In this study, Sr and Ba in coal and coal combustion products (fly and bottom ashes) from two coal-combustion power plants from North China analyzed by XRF and ICP-MS were comparatively studied. The concentrations of Sr and Ba analyzed by ICP-MS, when a mixture of acids (2 ml HF + 5 ml HNO 3 for each 50 mg coal sample and 5 ml HF + 2 ml HNO 3 for each 50 mg ash sample) was used for microwave-assisted digestion, do not fit well with the their relative XRF results. This is most probably due to the formation of the fluorides during microwave digestion, and this assumption is supported by the presence of various fluoride compounds, NaMgAl(F, OH) 6 ·H 2 O, NH 4 MgAlF 6 , AlF 3 , and K 2 SiF 6 , in the residues of all the coal and ash samples in our sequential extraction experiment. Cations of Sr and Ba were probably trapped into the divalent cation sites of the fluorides. Concentrations of Sr and Ba analyzed by ICP-MS using increased HF and HF/HNO 3 ratio (7 ml HF and 2 ml HNO 3 for each 50 mg coal/ash sample) are in better agreement with the XRF results. Our results indicate that excess amount of HF probably has led to the suppression of these elements due to fluoride precipitation. The results indicate that the modified digestion method is capable of achieving complete digestion of coal samples and results in a reliable analysis of Sr and Ba concentrations in coal samples and most fly ashes by ICP-MS. However, the formation of insoluble fluorides is probably not completely suppressed for some bottom ash samples, which can result in underestimation of Sr and Ba concentrations. Nevertheless, XRF analysis can serve as a reliable cross-check method to assist in the evaluation of the accuracy of ICP-MS results.
研究领域:
环境科学
·
分析化学
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地球化学
✓ 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）