Preparation of an ultra-low ash coal extract under mild conditions

Renganathan, K.; Zondlo, John W.; Mintz, Eric A.; Kneisl, Philip; Stiller, Alfred H.

doi:10.1016/0378-3820(88)90051-3

Cited by 59 publications

(32 citation statements)

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“…Extraction yields between 20 and 74% (daf basis) for bituminous coals have been reported. [14][15][16][17] The effect of changes in MALDI ion extraction voltage, in the 10-30 kV range, on the detection efficiency of large-MM materials, has been investigated using the tetrahydrofuran (THF) insoluble fraction of a coal tar pitch, deposited on target discs from solution in NMP. The THF-insoluble fraction comprised approximately 20% by mass of the pitch; the pitch sample and its fractions have previously been examined by MALDI at constant extraction voltages.…”

Section: Samplesmentioning

confidence: 99%

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Herod

Lázaro

Rahman

et al. 1997

Rapid Commun. Mass Spectrom.

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This paper describes experiments carried out within the framework of examining capabilities of MALDI-TOF-MS in the characterisation of fossil fuels and related materials. The work has focused on the effect of interactions between sample structure and matrix composition on the quality of MALDI spectra. Solvent extracts from six kerogens have been examined by MALDI-MS in the presence of three matrices of different composition and in the absence of matrix (laser ablation). The kerogen extracts have also been characterised by size exclusion chromatography (SEC) and UV-fluorescence spectroscopy (UV-F). In the presence of the three matrices (sinapinic acid, 2,5-dihydroxybenzoic acid and α-cyano-3-hydroxycinnamic acid), spectra of extracts from the three geologically 'younger' kerogens showed larger molecular mass distributions compared to spectra of extracts from the corresponding 'older' kerogens. This result directly contradicted trends observed in the absence of matrix, where extracts from 'older' kerogens showed larger molecular mass distributions. Results from SEC and UV-F agreed with trends observed in MALDI-spectra acquired in the presence of matrix, particularly sinapinic acid. By contrast, we recently reported that high mass signal in laser ablation mass spectra of the pyridine-insoluble fraction of a coal tar pitch, obtained in the absence of matrix, closely matched signals obtained in the presence of sinapinic acid. Compared to the highly condensed aromatic structure of the coal tar pitch, the kerogen extracts (of considerably higher oxygen content) appear less able to readily absorb incident laser radiation (337 nm) in the absence of externally added matrix. The argument is consistent with apparently more efficient absorption of incident laser radiation by the geologically 'older' samples, when no matrix was used. Structural characteristics suggest that the geologically 'older' samples would be better able to act as 'self-matrix'. Thus, differences in structure and composition of the samples appear to go some way towards explaining differences between trends observed in the presence/absence of matrix. Dependence of MALDI spectra on molecular structure has also been found for two sets of biomass derived samples. Considerably more work appears warranted to determine MALDI-MS parameters appropriate to the analysis of the more oxygenated, lower rank, samples. Recently, 1,2 we described changes in the MALDI-TOF mass spectra of coal derived liquids as a function of changes in (i) ion extraction voltage, (ii) laser power (iii) matrix composition and (iv) sample deposition density. Increasing ion extraction voltages helps provide a more complete inventory of species already ionised, without otherwise disturbing the sample. It would appear advantageous, therefore, to use the highest possible values of the extraction voltage, apparently irrespective of other experimental parameters. Clearly, the upper limit of the ion extraction voltage is determined by the capabilities of installed hardware. We have, to date, been a...

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Section: Samplesmentioning

confidence: 99%

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Herod

Lázaro

Rahman

et al. 1997

Rapid Commun. Mass Spectrom.

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“…The action of NMP at boiling conditions is remarkably enhanced. Renganathan et al [6] showed that coal extraction increases with increases in temperature and the amounts of extracted coal could be as high as 74% with as little as 0.1% ash using a temperature of 202 C at atmospheric pressure. In general, swelling=solvolysis of coal increases with time and temperature [2].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Solvent Extract of an Indian Coal

Nag

Biswas

Chandaliya

et al. 2011

International Journal of Coal Preparation and Utilization

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This article describes characterization of a solvent-extracted Indian coal obtained from four different seams of the West Bokaro coal mines. The coal samples were extracted with the solvent N-methyl-2-pyrrolidone. Ethylenediamine was used as co-solvent. Extracts were analyzed for elemental, microscopical and swelling properties. Functional group analysis was conducted using the Fourier transform infrared spectroscopy (FTIR). A comparative study made with parent coal showed that extraction with organic solvent brings about a considerable increase in lower molecular weight organic components, lowers the ash content and improves the swelling property of coal. FTIR studies provided some information about the functional group present in the parent and extracted coals.

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“…Under the mild conditions of 200$4008C and 1$5 MPa, the resultant extract has a very low-ash content, typically of the order of 0.1wt% or less. [1][2][3][4][5] Such an ultraclean fuel is expected to have a variety of applications. Its direct combustion in gas turbine can achieve a power generation efficiency of $48%, and, hence, mitigating CO 2 emission.…”

Section: Introductionmentioning

confidence: 99%

“…21 Coal extraction is commonly conducted by dissolving coal in an organic solvent at 350$4008C in $1 MPa (cold) nitrogen. [1][2][3][4][5] Subsequently, the resulting extractable fraction is isolated by filtration using a stainless filter having a pore size of $0.5 mm in a laboratory-scale process. Due to their highly organic affinity, the organometals including the transition metals (Fe, Cu, Cr, Mn, Ni, Cr, etc.…”

Section: Introductionmentioning

confidence: 99%

Elution of Ti during solvent extraction of coal and the transformation of eluted Ti upon combustion

et al. 2008

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in Wiley InterScience (www.interscience.wiley.com). Solvent extraction of coal is an effective method for removing coal ash, thereby generating the ultraclean fuel that can be directly combusted in gas turbine. Due to their organic affinity, a few inorganic elements can be extracted as well. Ti in coal extract, its elution from raw coal as well as the transformation of eluted Ti during coal extract combustion, have been investigated. Two coals of the U.S. and their acid-washed samples were extracted under 1 MPa N 2 (cold) at 3608C. The solvents used include nonpolar 1-methynaphthalene and its mixtures with polar indole. The results indicate that, Ti in coal extracts is mainly composed of nanoparticles including TiO 2 (anatase) and Ti associated with quartz. These particles are insoluble in any acids, having a fine dispersion into coal matrix. Upon coal fragmentation at 3608C, they could be librated, and, hence, traversed the filter for isolating coal extracts. The organo-Ti was preferentially extracted as well, which is most likely in a form of Ti porphyrin or Ti chelated with phenol-oxygen. These findings also have implications for revealing the modes of occurrence of Ti in the raw coals. Combustion of coal extract at 1,0008C resulted in the formation of nanometric TiO 2 polymorphs and much complex compound like FeZnTiO 4 . The former species could be mainly formed by the phase change of TiO 2 (anatase) at high-temperatures, while formation of the latter one could involve the capture of metallic vapors like Zn on TiO 2 polymorphs. The resultant nanoparticles may escape the conventional pollution control devices, causing environmental concern. Figure 2. Ti-bearing quartz in the extract generated by extraction of sulfuric acid-washed IL coal by a mixed solvent having 40% IN. Panels (b) and (d) are the EDS results for panels (a) and (c), respectively.

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Preparation of an ultra-low ash coal extract under mild conditions

Cited by 59 publications

References 1 publication

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Characterization of Solvent Extract of an Indian Coal

Elution of Ti during solvent extraction of coal and the transformation of eluted Ti upon combustion

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