Refining of Indian coals to obtain super clean coals having insignificant amounts of deleterious elements under milder conditions

et al. 2020

Preprint

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The present work aims at studying five Indian coals and their solvent extracted clean coal products using Py-GCMS analysis and correlating these characterizations with results from theoretical a principal component analysis. The pyrolysis products of the original coals and the super clean coals were classified as mono-, di and tri- aromatics while other prominent products that were obtained included cycloalkanes, n-alkanes and alkenes ranging from C10-C29. The Py-GCMS results for the samples were studied using Principal Component Analysis. Inferences on relative composition of constituent compounds and functional groups and structural insights based on scores and loading plots of the PCA analysis were consistent with the experimental observations. ATR-FTIR studies confirmed the reduced concentration of ash in the super clean coals and the presence of aromatics. The Py-GCMS data and the ATR-FTIR spectra led to the conclusion that the super clean coals behaved similarly for both coking and non-coking coals with high aromatic concentrations as compared to the raw coal. Neyveli lignite super clean coal was found to show some structural similarity with the original coals, whereas, the other super clean coal showed structural similarity among them but not with their original coals indicative of the selective action of the e,N solvent system on the polycondensed aromatic structures in coal.

Section: Pca Analysismentioning

confidence: 91%

Insights From Principal Component Analysis Applied to Py-GCMS Study of Indian Coals and Their Solvent Extracted Clean Coal Products

Roy

et al. 2020

Preprint

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“…The samples were dried and extracted with N-methyl pyrrolidone and a small amount of ethylenediamine. The procedure reported by Dhawan and Sharma (2019) was used to recover the SCCs. The extraction yields of the coals and the ash contents in the SCCs are given in Table S3 (in Supplementary data) (Fig.…”

Section: Samples and Geological Settingmentioning

confidence: 99%

“…The ATR-FTIR spectral analysis of the raw (OC), residual coal (left after the SCC extraction), and SCC was performed using Nicolet 6700 Infra-Red Spectrometer. ATR-FTIR spectra were recorded in the range 4000-600 cm -1 using a Ge crystal with a resolution of 4 cm -1 with 32 scans (Odeh 2015;Dhawan and Sharma 2019).…”

Section: Atir-ftir Spectramentioning

confidence: 99%

Insights from principal component analysis applied to Py-GCMS study of Indian coals and their solvent extracted clean coal products

Roy

et al. 2021

Int J Coal Sci Technol

Self Cite

The present work aims at studying five Indian coals and their solvent extracted clean coal products using Py-GCMS analysis and correlating the characterization data using theoretical principal component analysis. The pyrolysis products of the original coals and the super clean coals were classified as mono-, di- and tri-aromatics, while other prominent products that were obtained included cycloalkanes, n-alkanes, and alkenes ranging from C10–C29. The principal component analysis is a dimensionality reduction technique that reduced the number of input variables in the characterization dataset and gave inferences on the relative composition of constituent compounds and functional groups and structural insights based on scores and loading plots which were consistent with the experimental observations. ATR-FTIR studies confirmed the reduced concentration of ash in the super clean coals and the presence of aromatics. The Py-GCMS data and the ATR-FTIR spectra led to the conclusion that the super clean coals behaved similarly for both coking and non-coking coals with high aromatic concentrations as compared to the raw coal. Neyveli lignite super clean coal was found to show some structural similarity with the original coals, whereas the other super clean coals showed structural similarity within themselves but not with their original coal samples confirming the selective action of the e,N solvent in solubilizing the polycondensed aromatic structures in the coal samples.

“…There is also a scope of using some other inexpensive solvents in the development of an economically attractive process using milder ambient pressure conditions (Dhawan et al 2018;Dhawan and Sharma 2019). Advantages of using milder conditions over higher pressure at elevated temperatures in the solvent extraction of coal have already been discussed recently by Sharma and Dhawan (2018) and Dhawan and Sharma (2019). Therefore further research in this direction may lead to the development of an economical process of separative refining of coal through solvent extraction.…”

Section: Economizing the Organo-refining Of Coalsmentioning

confidence: 99%

“…Earlier scholars have reported on the development of a process of separative organo refining of coals using N-methyl pyrrolidone containing smaller amount of ethylenediamine (EDA) or diethylenetriamine (DETA) (Pande and Sharma 2001;Dhawan et al 2018;Dhawan and Sharma 2019). These separative organo-refining processes result in the production of SCCs having 0%-2% ash.…”

Section: Introductionmentioning

confidence: 99%

Fractionation of coal through organo-separative refining for enhancing its potential for the CO2-gasification

Kumar

et al. 2020

Int J Coal Sci Technol

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Coal gasification has already been extensively studied earlier under varying conditions of steam, CO2, O2, inert conditions. Belbaid coal and its e, N and NMP-DETA SCC products recovered through organo-refining under milder ambient pressure conditions were subjected to CO2-gasification in a fixed bed reactor under varying conditions. CO2 being an inert gas becomes the most challenging to be utilized during the gasification process. The SCCs showed better CO2-gasification reactivity than the raw Belbaid coal at 900 °C. The use of the catalyst K2CO3 tremendously increased the gasification reactivity for both raw coal and the SCCs. The use of sugarcane bagasse for CO2-gasification along with raw coal as well as with residual coal was also studied. Gasification under CO2 atmosphere conditions was used to structurally understand the coals as the coal structure gets loosened after extraction.