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Journal ArticleDOI

A comparative study on the rheological properties of two coal water slurries with sodium tripolyphosphate as dispersant

TL;DR: In this article, coal water suspensions of two different Indian coals (namely Coal 1 and Coal 2) were successfully prepared and their rheological behaviors were tested in the shear rate range of 60-160 s−1 for the...
Abstract: Coal water suspensions of two different Indian coals (namely Coal 1 and Coal 2) were successfully prepared and their rheological behaviors were tested in the shear rate range of 60–160 s−1 for the ...
Citations
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Journal ArticleDOI
TL;DR: The coal-water mixture (CWS) is a complex solid-liquid dispersion as mentioned in this paper, which is a mixture of coal slurry and water mixture, and is used for coal combustion.
Abstract: Coal–water slurry or coal–water mixture (CWS or CWM) is a complex solid–liquid dispersion. Several research works have been done concerning the production and use of CWSs being developed worldwide in several different governmental, industrial and academic facilities. In the present paper, studies on the developments achieved in the past three decades with regard to the field mentioned above are systematically reviewed, with particular regard to several different aspects during the combustion process. The structure and properties of the coal are highlighted, as are the different additives used and their adaptability with different types of coal, where the particle size distributions are of great importance in determining both the slurryability of coal and the rheological behavior of a produced CWS for its intended characteristics. At a time when there is much debate about the end of the age of coal as a primary source of thermal and electrical energy, alternative forms of use that can contribute to the reduction of pollutant emissions, as well as particles, in the atmosphere offer alternatives that may allow us to continue using coal, at least during this transition period until a viable alternative is found. In-depth knowledge of these coal slurries may allow, in the future, the development of similar products produced from fuels derived from biomass, such as charcoal or torrefied biomass.

21 citations

Journal ArticleDOI
15 May 2021-Fuel
TL;DR: In this paper, the addition of isoamyl alcohol and sec-octyl alcohol on the viscosity of coal water slurry (CWS) was investigated and comprehensively analyzed.

16 citations

Journal ArticleDOI
TL;DR: In this paper , a review of coal-water suspension (CWS) combustion processes is presented, where the authors have systematized mathematical models of CWS combustion processes, the sequence of analytical and experimental studies, and have also shown the global genesis of the CWS use.
Abstract: Research in the field of building mathematical models for combustion processes has been ongoing ever since the chemical reactions of combustion were first discovered. The authors of this review have systematized mathematical models of coal–water suspension (CWS) combustion processes, the sequence of analytical and experimental studies, and have also shown the global genesis of the CWS use. In addition, this review touches upon a topic that is inextricably linked with the combustion of CWS, namely their transportation from the place of coal mining to their place of thermal utilization. For developing countries, their own energy independence is in the foreground, as it is the basis for their economic independence and also a means for other sectors of their economy to be protected from the impact of market changes in fuel prices in the future spot world market. The authors of this review explored the possibility of using Kyrgyz brown coal and transporting it through a coal pipeline from a mountainous area to an industrial site for thermal utilization in specialized steam boiler units. As the economic analysis showed, for the conditions of the Republic of Kyrgyzstan, the use of CWS and coal pipelines with rising prices for natural gas is economically justified. The recommendations of the authors are used in scientific reports and methodological recommendations for the energy and mining sectors of the Republic of Kyrgyzstan, how the recommendations can also be applied to similar conditions in the highlands of Russia, China, and India.

1 citations

Journal ArticleDOI
12 May 2021
TL;DR: In this article, the effects of two anionic dispersants (polymeric-carboxy methyl cellulose: CMC and inorganic-sodium tripolyphosphate: STPP) on the rheological properties of coal water slurries of varying solid loading were reported and compared.
Abstract: The effects of two anionic dispersants (polymeric-carboxy methyl cellulose: CMC and inorganic-sodium tripolyphosphate: STPP) on the rheological properties of coal water slurries (CWS) of varying solid loading were reported and compared. The rheological data was obtained in the shear rate range of 60-160 s -1 and the data was fitted using power law model. For lower solid concentrations (10% and 20%), shear thickening behaviour was observed while shear thinning nature was seen for the higher solid loadings (30%,40% and 50%) for CWS with both the dispersants. For all slurries, an increase in flow behaviour index values was seen with the increase of dispersant loading. For CWS of 10% and 20% solid loadings, lower values of flow behaviour index was observed with CMC as dispersant. On the other hand, lower values for flow behaviour index was seen with STPP as dispersant for CWS of 30%, 40% and 50% solids loading. Although CMC was found very effective in reducing the apparent viscosity at lower dosages unlike STPP, the apparent viscosity values are quite sensitive to the loading of CMC as dispersant in comparison to STPP. This observed trend may be due to aggressively induced negative charges upon the adsorption of CMC on coal particles at the tested dispersant dosages.

Cites background from "A comparative study on the rheologi..."

  • ...Several types of dispersants (anionic, non-ionic, polymeric and natural etc) for coal water slurries were successfully tested and reported in the literaure [7-9]....

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References
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Journal ArticleDOI
TL;DR: In this paper, the rheological behavior of Indian coal-water slurry (CWS) was investigated using a HAAKE RV30 viscometer, and the effect of temperature on the viscosity could be described using an Arrhenius type of relation.
Abstract: The rheological behavior of some Indian coal-water slurry (CWS) was investigated using a HAAKE RV30 viscometer. The objective was to study the effect of solid concentration, ash content, pH, and temperature on the rheology of CWS. It was found that CWS exhibits pseudoplastic behavior. The apparent viscosity varies with the amount of coal in the slurry, pH, and temperature, which is the highest around pH 6 and the lowest near pH 8. The effect of temperature on the viscosity could be described using an Arrhenius type of relation.

114 citations


"A comparative study on the rheologi..." refers background in this paper

  • ...The increase of solids concentration increases the interaction among the particles with significant friction among them (Mishra, Senapati, and Panda 2002)....

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  • ...…of CWS (Coal 1 and Coal2) of different solids loading, (a) 10%, (b) 20%, (c) 30%, (d) 40% and (e) 50%. apparent viscosity at higher shear rate was due to the continuous breakdown of slurry structure and continuous or sudden breakdown of aggregates in the slurry (Mishra, Senapati, and Panda 2002)....

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Journal ArticleDOI
TL;DR: In this article, two commercially available deflocculants were used to evaluate the effectiveness of some commercial dispersing agents employed for maximizing the solid loading of kaolin suspensions, and the results showed that the sodium polyphosphate proved to be more effective as dispersant for kaolin suspension.

109 citations


"A comparative study on the rheologi..." refers background in this paper

  • ...As a result, the apparent viscosity increases with increase in dispersant loading after the saturation limit (Papo, Piani, and Ricceri 2002)....

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Journal ArticleDOI
TL;DR: In this article, the use of a surfactant mixture of natural and synthetic surfactants as additives in stabilizing coal-water slurry (CWS) formed from low rank Indian coals has been explored.

104 citations


"A comparative study on the rheologi..." refers background in this paper

  • ...Much of the investigations were carried out in use of different dispersants for CWS like anionic, non-ionic and natural dispersants, etc. (Das et al. 2013; Yoon, Choi, and Lee 2009) and polymeric dispersants, in particular, have been found to be effective additives in stabilizing the coal water…...

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Journal ArticleDOI
01 Aug 1995-Fuel
TL;DR: In this paper, the authors investigated the rheological properties of coal-water mixture, including the coal properties, the volume fraction of solids and the mean size and size distribution of the coal particles.

103 citations


"A comparative study on the rheologi..." refers background in this paper

  • ...…coal oxidation, and the quantity of surface active functional groups; (2) the volume fraction, ϕ, of the suspension; (3) the particle size range and its distribution; (4) interparticle interactions in the suspension and their effects of pH and the chemical additives, etc. (Nam-Sun-Roh et al. 1995)....

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Journal ArticleDOI
TL;DR: In this article, the surface charge distribution of muscovite and vermiculite was evaluated using electrokinetic zeta potential measurements and potentiometric titrations, and the results showed that muscivite particles have an apparent negative charge due to the high aspect ratio of the negatively charged tetrahedral faces to the edges within a tetrasilicate-octahedral-tetrahedral layer configuration.

89 citations


Additional excerpts

  • ...Rheology is an important research tool that can be used to characterize the ores/ minerals based on the flow properties of the constituent gangue minerals (Ndlovu et al. 2011)....

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