Feasibility of using ultrasound-assisted process for sulfur and ash removal from coal
TL;DR: In this article, the authors investigated utilization of ultrasound in reagent-based coal de-ashing and de-sulfurization and derived an empirical model for the prediction of total sulfur removal.
Abstract: The present work investigates utilization of ultrasound in reagent-based coal de-ashing and de-sulfurization. The coal under study was received from Girald mine, Rajasthan, India. Three different ultrasonic frequencies (25 kHz, Dual (58/192 kHz) and 430 kHz) and three reagents (HCl, HNO 3 and H 2 O 2 ) were used. The study employed a Taguchi fractional-factorial L 27 DOE. Experimental data were used to derive an empirical model for the prediction of total sulfur removal. The model incorporates cavitational intensity, reagent concentration, sonication time, coal particle size and coal concentration as key parameters. Effects of above factors on reagent-based ultrasonic coal-desulfurization are presented here. An optimum set of process parameters are identified and validated. Larger-scale trial with high-ash and high-sulfur coals is strongly recommended.
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TL;DR: In this paper, the authors reported the application of ultrasonic energy (20 kHz) to few high sulphur Indian coal samples in aqueous and mixed alkali media (1:1 KOH and NaOH) for removal of sulphur and ash for industrial applications.
66 citations
Cites methods from "Feasibility of using ultrasound-ass..."
...Therefore, in this investigation low frequency ultrasound (20 kHz) has been used and found to be more effective in coal particle breakage due to increased cavitations [18,19]....
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TL;DR: A critical review of the ultrasound mechanism in enhancing coal demineralization, desulphurization, grindability, slurryability and dewatering is reviewed, which can significantly increase the clean coal yield under the substantial effect of cavitation and streaming.
45 citations
TL;DR: In this article, an attempt of using low ultrasonic energy (20 kHz) to clean some low rank medium to high sulfur coal samples from northeast India in the presence of H2O2 solutions was reported.
45 citations
TL;DR: In this paper, an oxidized and high sulphur fine coal was subjected to oil agglomeration process after ultrasonic treatment, and the results showed that the performance of the coal improved significantly.
36 citations
TL;DR: In this article, low ash clean coal was produced from Indian coking coal through microwave irradiation or ultrasonication followed by solvent extraction in N-methyl-2-pyrollidone (NMP) containing smaller amount of Ethylenediamine (EDA) or Monoethanolamine (MEA).
35 citations
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TL;DR: At all temperatures and pressures studied, the power output increased exponentially when the amplitude was increased linearly, and the magnitude of this power output did not depend on the temperature or pressure of treatment.
288 citations
TL;DR: A number of analytical methods have been developed for approximating the sulfur functional group compositions of coals as discussed by the authors, and some of these are destructive tests depending on pyrolysis or catalytic reduction to H 2 S or oxidation to SO 2.
230 citations
TL;DR: It was found that the activated carbon is the best support for pi-complexation sorbents to remove sulfur-containing compounds, i.e., benzothiophene and methylbenzothiopane.
Abstract: Several carbon-based adsorbents, CuCl/AC, PdCl2/AC, and Pd/AC (where AC denotes activated carbon), were studied for desulfurization of a model jet fuel by selective adsorption of thiophenic molecules. Comparisons with γ-Al2O3 support and desulfurization of a commercial jet fuel were also studied. The results showed that the selective sulfur adsorption capacity of PdCl2 was higher than that of CuCl and Pd0, in agreement with molecular orbital results. It was also found that the activated carbon is the best support for π-complexation sorbents to remove sulfur-containing compounds, i.e., benzothiophene and methylbenzothiophene. Among all the adsorbents studied, PdCl2/AC had the highest capacity for desulfurization. A significant synergistic effect was observed between the carbon substrate and the supported π-complexation sorbent, and this effect was explained by a geometric effect. The saturated sorbent was regenerated by desorption assisted by ultrasound with a solvent of 30 wt % benzene and 70 wt % n-octan...
149 citations