Preparation of high concentration coal water slurry with good fluidity based on only modified fine particles under bimodal distribution using the second fluid and the second particle

Yao, Dingsong; Zhao, Hui; Chen, Zhekun; Liu, Haifeng

doi:10.1016/j.fuel.2022.123461

Cited by 20 publications

(6 citation statements)

References 43 publications

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“…Meanwhile, the filling slurry used in the field of fracture body injection is usually a cement slurry or a chemical slurry [29][30][31]. Generally, its purpose is to increase the groutability and diffusivity of the slurry, but the modification cost is higher [32][33][34][35]. Therefore, significant differences exist between the two engineering contexts.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Diffusion Radius of Modified Slurry Used in Longwall Overburden Isolated Grouting

Xuan

Zhang

et al. 2023

Geofluids

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The slurry diffusion radius is an important parameter in grouting engineering. In some cases, injection into partial overburden is needed in grouting engineering, and it is thus critical to control the slurry diffusion so as to reduce unnecessary grout take. In an effort to solve such issues in longwall overburden grouting, we proposed the addition of cement as a means of modifying fly ash slurry in order to reduce grout diffusion and grout take. The characteristics of the modified slurry were determined under different water-ash ratios and cement-blending ratios. The cement-blending ratio was found to have a small effect on the density of the slurry but a significant effect on the slurry’s precipitation rate and viscosity. The slurry diffusion experimental system was established to study the diffusion radius and consolidation. Results for both the fly ash slurry and the modified slurry revealed a circular diffusion pattern centered around the grouting borehole. The diffusion radius of the modified slurry made with 10% cement was 19.4% lower than that of the fly ash slurry, but its solidification thickness appeared to increase. The modified slurry diffusion had a two-stage effect: a “stability control stage” and a “consolidation control stage.” In the consolidation control stage, the diffusion radius of the modified slurry was smaller than that of the fly ash slurry, and this stage was the key to control the diffusion radius of the slurry. Field trials were conducted based on the results of the study, and grout take was reduced effectively. This research provides a theoretical basis for slurry diffusion radius control in longwall grouting.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on the Diffusion Radius of Modified Slurry Used in Longwall Overburden Isolated Grouting

Xuan

Zhang

et al. 2023

Geofluids

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“…6,7 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. 8 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. Gustavo et al 9 discovered that ultrafine particles could create an increased reactivity to combustion because ultrafine particles with large surface areas react faster than large particles with the same volume.…”

Section: Introductionmentioning

confidence: 99%

“…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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“…Successful practical application of highly loaded liquid systems comprising a solid phase necessitates in-depth investigation of their properties, which include kinetic and aggregative stability; i.e., the stable concentration homogeneity of the distribution of the dispersed phase particles in the dispersion medium volume is held in place. In ref ( 3 ), it was shown that preliminary modification of the surface of fine coal particles by kerosene suspension and ultrafine petroleum coke substantially improved the rheological properties of ready coal water fuel (CWF) in the presence of a dispersing agent. However, the distribution of the solid coal fraction was strictly controlled and was bimodal.…”

Section: Introductionmentioning

confidence: 99%

Impact of Hydrodynamic Cavitation on the Properties of Coal-Water Fuel: An Experimental Study

et al. 2022

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It is common to use coal as raw material in heat power engineering. A number of shortcomings of coal such as ignitability cannot be easily eliminated. The use of water-slurry-based coal-water fuel instead of coal eliminates this problem. The coal-water fuel (CWF) is liquid fuel, which means that the main line of investigation is to study its sedimentation and rheological properties responsible for the transport and atomization in the boiler and thermal-physical properties which determine the expedience and efficiency of its application. The paper shows that the final performance properties of suspended coal fuel can be determined at the stage of CWF preparation by hydrodynamic treatment of aqueous coal slurry. The rheological and sedimentation properties and combustion parameters of water-coal fuel, ignition time of the drop, its completeness of combustion, and amount of man-made emissions, have been studied. Studies have been carried out on coals from the Kansk-Achinsk coal basin (Russia). The studies were performed under laboratory conditions with a hydrodynamic rotary mixer, making it possible to attain cavitation effects in the processed medium. Two CWF types have been considered: the first was produced by cavitation dispersion of the solid coal fraction in distilled water, and the second was produced in analogy, but the dispersion medium was water pretreated by cavitation. The paper shows that the cavitation method of producing CWF improves the rheological and sedimentation properties of the end-use fuel, reduces hazardous emissions in combustion, and affects the combustion parameters.

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Preparation of high concentration coal water slurry with good fluidity based on only modified fine particles under bimodal distribution using the second fluid and the second particle

Cited by 20 publications

References 43 publications

Experimental Study on the Diffusion Radius of Modified Slurry Used in Longwall Overburden Isolated Grouting

Experimental Study on the Diffusion Radius of Modified Slurry Used in Longwall Overburden Isolated Grouting

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

Impact of Hydrodynamic Cavitation on the Properties of Coal-Water Fuel: An Experimental Study

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