Open AccessA comparative study on the rheological properties of coal water slurries using sodium tripoly-phosphate and carboxy-methyl-cellulose as dispersants
Author(s) -
M. Ananda Rao,
M. V. Pavan Kumar,
Lenka Srinu
Publication year - 2021
Publication title -
journal of mines, metals and fuels
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.125
H-Index - 11
ISSN - 0022-2755
DOI - 10.18311/jmmf/2021/27787
Subject(s) - dispersant , rheology , slurry , apparent viscosity , coal water , cellulose , chemical engineering , materials science , shear thinning , shear rate , chemistry , viscosity , chromatography , composite material , organic chemistry , dispersion (optics) , physics , optics , engineering
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.