Evaluation of the Influence of Mixtures of Nonionic Surfactants on the Rheology of Bituminous Coal-water Slurry using Simplex Centroid Mixture Design

Abstract

With the objective of developing a rheology modifier to enhance the transportation of the Coal-water slurry (CWS) via long-distance pipelines, the effects of three nonionic surfactants, which are Polyethylene oxide (PEO), Polyvinyl alcohol (PVA), p-tert-octylphenoxy-polyethoxyethanol (Triton X-405) and their mixtures on the apparent viscosity of bituminous coal-water slurry (CWS) were investigated using the simplex-centroid mixture design. Based on the results of the mixture design and with consideration to the cost of the surfactants, a binary PEO:PVA mixture was developed with proportions of 0.495:0.505. The addition of the nonionic mixture at a concentration of 0.5 wt% to the CWS with a dry solids content of 50 wt% decreased its apparent viscosity by 56.16%. This reduction in the apparent viscosity is owed to the increase of the hydrophobicity of the coal particles due to the adsorption of the PEO and PVA on the surface of the particles. At a concentration of 0.5 wt%, the nonionic mixture was also found to enhance the shear-thinning flow behavior of the CWS by decreasing the value of the flow behavior index (n). The addition of the nonionic mixture to the CWS at concentrations of 0.75 wt% and above displayed adverse effects on the shear-thinning flow behavior of the CWS owing to the high molecular weight of the polymers, which results in entanglement of the long hydrophobic chains of PEO and PVA when present at high concentrations in the CWS.

Department(s)

Chemical and Biochemical Engineering

Keywords and Phrases

Coal water slurry; nonionic surfactant; simplex centroid mixture design; slurry rheology

International Standard Serial Number (ISSN)

1532-2351; 0193-2691

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Taylor and Francis Group; Taylor and Francis, All rights reserved.

Publication Date

01 Jan 2025

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