Effects of Metal Ions in Organic Wastewater on Coal Water Slurry and Dispersant Properties

Liu, Jianzhong; Wang, Shuangni; Li, Ning; Wang, Yi; Li, Dedi; Cen, Kefa

doi:10.1021/acs.energyfuels.9b01146

Cited by 26 publications

(10 citation statements)

References 28 publications

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“…), which would bring serious threats to the ecological environment. − Accordingly, oil, organic solvents, and wastewater (industrial wastewater, petroleum and coal processing wastewater, sewage sludge wastewater, etc.) can be used as substitutes for the aqueous medium to efficiently recycle the heat value and deal with pollutants. − The inorganic matters in CWS can be deposited in slag and fly ash after combustion and gasification, and the organic substances can be converted chemically or burned directly to generate electricity. Especially during the combustion process, the organic pollutants would be turned into gaseous small molecular matters like SO x , NO x , and CO 2 , which are easy to handle. − …”

Section: Introductionmentioning

confidence: 99%

Review and Perspectives of Anionic Dispersants for Coal–Water Slurry

Feng

et al. 2023

Energy Fuels

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Dispersants are chemical moieties that modify interfacial characteristics by adsorption at the solid–liquid interface, and they have been widely used in modern industrial production. This review focuses on the research and perspectives of anionic dispersants for coal–water slurry (CWS). Various common anionic dispersants are briefly summarized, including natural and synthetic species. The interactions between coal particles in the CWS suspension, including van der Waals attraction and electrostatic repulsion, are described by the DLVO (Derjaguin–Landau–Verwey–Overbeek) theory. Due to the hydrophobic interaction and the steric effect resulting from the adsorption of polymer dispersants, the extended DLVO theory is introduced to elucidate the various interactions in the CWS system. Based on the interactions between the coal particles, the adsorption behaviors at the coal–water interface, and the interactions between coal and water, the dispersion and stabilization mechanisms are systematically and theoretically discussed. According to the variations of interaction energies between the coal particles, the use of anionic polymer dispersants can weaken the hydrophobic attraction and enhance the steric hindrance and electrostatic repulsion. Also, the rheological behaviors of CWSs are outlined, with emphasis on the pipeline transportation of CWS and the three-parameter Herschel–Bulkley model. Additionally, the properties of anionic dispersants for CWS can be improved by adjusting their chemical structures such as molecular weight, side chain length, rigidity and flexibility of the molecular chain, and variety, quantity, position, and proportion of hydrophobic and hydrophilic groups. In view of the relationships between the structure and property, a direction on the selection and preparation of dispersant for CWS is suggested. Finally, the current challenges and future perspectives of dispersants for CWS are put forward.

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Section: Introductionmentioning

confidence: 99%

Review and Perspectives of Anionic Dispersants for Coal–Water Slurry

Feng

et al. 2023

Energy Fuels

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“…Considering the current national conditions at this stage, coal will continue to be one of the most vital energy sources, especially in America, Russia, Australia, China, and India. − Coal water slurry (CWS) is a kind of coal-based liquid fuel for gasification and combustion, and its consumption has exceeded 230 million tons/a in China. , The traditional CWS is made up of 50–70% (mass percent, the same mentioned below) pulverized coal with a mean size of 40–50 μm and an ash content of 7–12% as well as 30–50% water and a little bit of chemical additives. , It is regarded as an environmentally friendly way of utilizing coal resources to produce CWS, which could be used in the industry with a cleaner and more efficient way instead of solid coal . Although the traditional CWS has been successfully applied in many boilers, furnaces, and kilns to replace heavy oil and residue oil fuel, it cannot be used in gas turbines and internal combustion engines to replace diesel oil fuel.…”

Section: Introductionmentioning

confidence: 99%

Insights into the Dispersion Mechanism of Microfine Coal Particles Modified with Naphthalene Sulfonate Formaldehyde Based on EDLVO Theory

et al. 2023

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Coal water slurry (CWS) fuel prepared using microfine coal particles with a size distribution of 1–10 μm is a promising way to cleanly utilize solid resources in engines, even catering a popular application for clean coal technology. In an attempt to address the problems in coal aggregation in microfine coal water slurry (MCWS), dispersants are used to improve the dispersing status of microfine coal particles. Based on the experimental results and extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) theory calculations, the role of naphthalene sulfonate formaldehyde (NSF) in MCWS performance was explored. The measurement of the slurry ability of microfine coals demonstrated that the apparent viscosity and yield stress of MCWS were decreased significantly with 1.5% NSF addition, which was consistent with the saturated adsorption value of NSF on microfine coals. Furthermore, the ζ-potential and contact angle of microfine coals were both decreased as a function of the NSF dosage, indicating that a larger electrostatic repulsion force and better wetting ability of the coal surface would be obtained in the presence of NSF. The thickness calculation results showed that the thickness is increased with NSF addition, which is attributed to that the NSF molecule extends into the surrounding solution to form a hydrophilic film. The EDLVO calculations illustrated that the total interaction was turned from an attractive force into a repulsive force in the case of NSF, noting that the better dispersion of microfine coals mainly resulted from the better hydrophilicity of the coal surface modified with NSF. The findings might provide guidance for MCWS preparation by revealing the interaction mechanism of microfine coals modified with NSF.

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“…The results showed that the waste‐derived slurry has an environmental and economic advantage 16 . Liu et al investigated the effect of six metal ions in organic wastewater on the properties of CWS and found that Fe 3+ can increase and Cu 2+ can decrease the apparent viscosity of the slurry, whereas Mg 2+ , Ca 2+ , K + , and Na + have no corresponding obvious effects 17 …”

Section: Introductionmentioning

confidence: 99%

“…16 Liu et al investigated the effect of six metal ions in organic wastewater on the properties of CWS and found that Fe 3+ can increase and Cu 2+ can decrease the apparent viscosity of the slurry, whereas Mg 2+ , Ca 2+ , K + , and Na + have no corresponding obvious effects. 17 Preparing CWWS from CGW is an effective way of waste utilization and emission reduction, and it is worth mentioning that the use of CO 2 as a gasification agent is also a research hotspot in the field of gasification. In gasification process, CO 2 can be converted into fuel gas CO through Boudouard reaction, which provides a reliable solution for reducing CO 2 in the atmosphere and producing new clean fuels.…”

Section: Introductionmentioning

confidence: 99%

Study on CO₂ gasification properties of coal gasification wastewater slurry

Liu

Wang

et al. 2021

Asia-Pacific J Chem Eng

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Coal water slurry technology and gasification technology are used to simultaneously treat wastewater and CO2; coal water slurry is prepared from fixed‐bed coal gasification wastewater; and then, thermogravimetric analysis, Fourier‐transform infrared spectrometry, scanning electron microscopy, energy‐dispersive spectrometry, and X‐ray diffraction are used to analyze the characteristic parameters of CO2 gasification and the products that formed. The results reveal the following: (a) compared with coal water slurry, coal gasification wastewater slurry shows decreases in the gasification start temperature, gasification weight loss peak temperature, and gasification end temperature of 12°C, 22°C, and 17°C, respectively, and shows increases in the maximum and average reaction rates. In addition, the reactivity index for coal gasification wastewater slurry is found to be 14.29% higher than that for ordinary coal water slurry. (b) Coal gasification wastewater slurry produces more methane and other aliphatic hydrocarbon gases in the pyrolysis stage and more CO in the coke gasification stage than coal water slurry. (c) Coal gasification wastewater slurry contains many small particles and flocs on the surface of the coal and a high Na content (up to 8.07%) in the microarea. In addition, a richer pore structure exists on the surface of the gasification residue of the coal gasification wastewater slurry. (d) The components of the gasification residue for coal gasification wastewater slurry show relatively larger changes. Moreover, the catalytic effect of alkali metal may be weakened due to the reaction of the minerals in the coal to form a complex.

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Effects of Metal Ions in Organic Wastewater on Coal Water Slurry and Dispersant Properties

Cited by 26 publications

References 28 publications

Review and Perspectives of Anionic Dispersants for Coal–Water Slurry

Review and Perspectives of Anionic Dispersants for Coal–Water Slurry

Insights into the Dispersion Mechanism of Microfine Coal Particles Modified with Naphthalene Sulfonate Formaldehyde Based on EDLVO Theory

Study on CO₂ gasification properties of coal gasification wastewater slurry

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Effects of Metal Ions in Organic Wastewater on Coal Water Slurry and Dispersant Properties

Cited by 26 publications

References 28 publications

Review and Perspectives of Anionic Dispersants for Coal–Water Slurry

Review and Perspectives of Anionic Dispersants for Coal–Water Slurry

Insights into the Dispersion Mechanism of Microfine Coal Particles Modified with Naphthalene Sulfonate Formaldehyde Based on EDLVO Theory

Study on CO2 gasification properties of coal gasification wastewater slurry

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Study on CO₂ gasification properties of coal gasification wastewater slurry