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Edward Lester - One of the best experts on this subject based on the ideXlab platform.
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A novel automated image Analysis method for Maceral Analysis
Fuel, 2002Co-Authors: Edward Lester, David Watts, Michael ClokeAbstract:A new image Analysis technique has been developed which allows Maceral Analysis of coal to be carried out. The technique is able to separate the liptinite component from the background resin by using two separate images of the surface captured with different camera exposure times. At normal exposure, the liptinite has a similar grey scale value to the surrounding resin, but at a higher exposure time, the resin remains black whilst the liptinite grey scale increases significantly enough to distinguish it from the resin. The method has been tested for repeatability and reproducibility and found to be within the ISO Standard requirements.
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the structure and reactivity of density separated coal fractions
Fuel, 1999Co-Authors: A Gilfillan, Michael Cloke, Edward Lester, Colin E SnapeAbstract:Density separations of six world coals have been carried out. The coals were provided as pf samples and were screened to provide size fractions at -38 + 20 μm from which tight density fractions (0.02 and 0.03 g cm -3 intervals) were produced in a heavy liquid medium using the float-sink procedure. Each density fraction was characterised by manual Maceral Analysis and a new automated image Analysis technique called the reactivity assessment program. The chemical structure of each fraction was examined by 13 C n.m.r. and FT-i.r. spectroscopies. The reactivity of the density fractions was assessed using a drop tube furnace at a temperature of 1300°C, residence time of 100 ms and 1 vol% oxygen atmosphere. The morphology of the chars produced in the drop tube furnace were examined manually and using an automated image Analysis technique. This allowed the predicted reactivity of the fractions to be correlated against actual burnout characteristics.
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the characterization of coals and density separated coal fractions using ftir and manual and automated petrographic Analysis
Fuel, 1997Co-Authors: Michael Cloke, A Gilfillan, Edward LesterAbstract:Abstract In the first part of this study density-separated, coal fractions of Point of Ayr coal were analysed using petrographic techniques and infrared (IR) spectroscopy. Density separations were carried out on the 38 + 20 μm size fraction using sodium polytungstate as the dense liquid medium. Petrographic Analysis and FTIR Analysis, using the diffuse reflectance technique, were carried out on the density-separated fractions. For the FTIR Analysis the samples were micronized to give a particle size of 2 μm which leads to a considerable improvement in the quality of the recorded spectra without the need for dilution with potassium bromide. Area measurements of the aromatic ( A Ar ) and aliphatic ( A Al ) CH stretch absorptions together with area ratios of these absorptions ( A Ar / A Al ) were determined for each of the density fractions and the feed coal. The A Ar / A Al ratios showed an increase with higher density, indicating a change in aromaticity as the density of the fractions is increased. A linear correlation between the area ratios and major Maceral Analysis was found. The results of this part of the study thus showed that changes in the IR spectrum could be directly related to the Maceral composition, and that the diffuse reflectance technique could be used to obtain consistent good quality IR spectra of powdered coals. Using the same FTIR technique the A Ar / A Al ratios of 29 world coals was found and correlated with Maceral analyses of the coal, Maceral Analysis plus rank and the grey-scale histogram produced during automated, petrographic Analysis of the coals using image Analysis. A poor correlation was obtained between Maceral Analysis and the A Ar / A Al ratio. The correlation improved markedly when rank was included, but the best correlation ( R 2 = 0.96) was obtained against the grey-scale histogram. This work indicates that it may be possible to use the diffuse-reflectance FTIR technique as a rapid characterization technique for coal reactivity.
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repeatability of Maceral Analysis using image Analysis systems
Fuel, 1995Co-Authors: Michael Cloke, Edward Lester, Martin Allen, N J MilesAbstract:Abstract This paper describes the effect of scanning patterns and number of images in each scan on the accuracy of automated image Analysis techniques used for Maceral Analysis. The results are compared with the accuracy of manual point counting. Current theoretical standards are discussed together with actual results obtained from within the laboratory. Ways of increasing the accuracy of automated Maceral Analysis using different methods of sampling with automatic staging is demonstrated, together with the number of images which need to be scanned.
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Automated Maceral Analysis using fluorescence microscopy and image Analysis
Fuel, 1995Co-Authors: Michael Cloke, Edward Lester, Martin Allen, Nicholas J. MilesAbstract:Abstract This paper describes the feasibility of using fluorescence microscopy in conjunction with normal white light microscopy and image Analysis in order to carry out fully automated Maceral Analysis. A short review of current image systems shows a lack of success in distinguishing the liptinite species from the resin media used to form the coal block. Fluorescent lighting is commonly used during manual Analysis and in this paper fluorescence is shown to provide a means of performing automated Maceral Analysis which includes an accurate determination of the liptinite content. The work presented indicates that the system can be used with a wide range of coals from around the world. A realistic assessment of repeatability and reproducibility is also made.
Michael Cloke - One of the best experts on this subject based on the ideXlab platform.
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A novel automated image Analysis method for Maceral Analysis
Fuel, 2002Co-Authors: Edward Lester, David Watts, Michael ClokeAbstract:A new image Analysis technique has been developed which allows Maceral Analysis of coal to be carried out. The technique is able to separate the liptinite component from the background resin by using two separate images of the surface captured with different camera exposure times. At normal exposure, the liptinite has a similar grey scale value to the surrounding resin, but at a higher exposure time, the resin remains black whilst the liptinite grey scale increases significantly enough to distinguish it from the resin. The method has been tested for repeatability and reproducibility and found to be within the ISO Standard requirements.
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the structure and reactivity of density separated coal fractions
Fuel, 1999Co-Authors: A Gilfillan, Michael Cloke, Edward Lester, Colin E SnapeAbstract:Density separations of six world coals have been carried out. The coals were provided as pf samples and were screened to provide size fractions at -38 + 20 μm from which tight density fractions (0.02 and 0.03 g cm -3 intervals) were produced in a heavy liquid medium using the float-sink procedure. Each density fraction was characterised by manual Maceral Analysis and a new automated image Analysis technique called the reactivity assessment program. The chemical structure of each fraction was examined by 13 C n.m.r. and FT-i.r. spectroscopies. The reactivity of the density fractions was assessed using a drop tube furnace at a temperature of 1300°C, residence time of 100 ms and 1 vol% oxygen atmosphere. The morphology of the chars produced in the drop tube furnace were examined manually and using an automated image Analysis technique. This allowed the predicted reactivity of the fractions to be correlated against actual burnout characteristics.
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the characterization of coals and density separated coal fractions using ftir and manual and automated petrographic Analysis
Fuel, 1997Co-Authors: Michael Cloke, A Gilfillan, Edward LesterAbstract:Abstract In the first part of this study density-separated, coal fractions of Point of Ayr coal were analysed using petrographic techniques and infrared (IR) spectroscopy. Density separations were carried out on the 38 + 20 μm size fraction using sodium polytungstate as the dense liquid medium. Petrographic Analysis and FTIR Analysis, using the diffuse reflectance technique, were carried out on the density-separated fractions. For the FTIR Analysis the samples were micronized to give a particle size of 2 μm which leads to a considerable improvement in the quality of the recorded spectra without the need for dilution with potassium bromide. Area measurements of the aromatic ( A Ar ) and aliphatic ( A Al ) CH stretch absorptions together with area ratios of these absorptions ( A Ar / A Al ) were determined for each of the density fractions and the feed coal. The A Ar / A Al ratios showed an increase with higher density, indicating a change in aromaticity as the density of the fractions is increased. A linear correlation between the area ratios and major Maceral Analysis was found. The results of this part of the study thus showed that changes in the IR spectrum could be directly related to the Maceral composition, and that the diffuse reflectance technique could be used to obtain consistent good quality IR spectra of powdered coals. Using the same FTIR technique the A Ar / A Al ratios of 29 world coals was found and correlated with Maceral analyses of the coal, Maceral Analysis plus rank and the grey-scale histogram produced during automated, petrographic Analysis of the coals using image Analysis. A poor correlation was obtained between Maceral Analysis and the A Ar / A Al ratio. The correlation improved markedly when rank was included, but the best correlation ( R 2 = 0.96) was obtained against the grey-scale histogram. This work indicates that it may be possible to use the diffuse-reflectance FTIR technique as a rapid characterization technique for coal reactivity.
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repeatability of Maceral Analysis using image Analysis systems
Fuel, 1995Co-Authors: Michael Cloke, Edward Lester, Martin Allen, N J MilesAbstract:Abstract This paper describes the effect of scanning patterns and number of images in each scan on the accuracy of automated image Analysis techniques used for Maceral Analysis. The results are compared with the accuracy of manual point counting. Current theoretical standards are discussed together with actual results obtained from within the laboratory. Ways of increasing the accuracy of automated Maceral Analysis using different methods of sampling with automatic staging is demonstrated, together with the number of images which need to be scanned.
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Automated Maceral Analysis using fluorescence microscopy and image Analysis
Fuel, 1995Co-Authors: Michael Cloke, Edward Lester, Martin Allen, Nicholas J. MilesAbstract:Abstract This paper describes the feasibility of using fluorescence microscopy in conjunction with normal white light microscopy and image Analysis in order to carry out fully automated Maceral Analysis. A short review of current image systems shows a lack of success in distinguishing the liptinite species from the resin media used to form the coal block. Fluorescent lighting is commonly used during manual Analysis and in this paper fluorescence is shown to provide a means of performing automated Maceral Analysis which includes an accurate determination of the liptinite content. The work presented indicates that the system can be used with a wide range of coals from around the world. A realistic assessment of repeatability and reproducibility is also made.
Colin E Snape - One of the best experts on this subject based on the ideXlab platform.
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improving spatial predictability of petroleum resources within the central tertiary basin spitsbergen a geochemical and petrographic study of coals from the eastern and western coalfields
International Journal of Coal Geology, 2017Co-Authors: Jacob Uguna, Colin E Snape, Chris Marshall, David Large, Will Meredith, Malte Jochmann, Andrew D Carr, Christopher H Vane, Maria Jensen, Snorre OlaussenAbstract:Central Tertiary Basin (CTB) coals from a variety of palaeogeographic conditions within the Longyear and Verkhnij seams, were sampled to assess the relationship between the petroleum present, the remaining generation potential and coal geochemistry in order to improve the spatial predictability of petroleum resources within the basin. Vitrinite reflectance (VR) values from the CTB coals have been shown to be suppressed (Marshall et al., 2015b). This study attempts to quantify and correct for this suppression effect by applying the Lo (1993) method (LoVR), which uses Hydrogen Index (HI) values to modify VR data, and the coal Rank(Sr) scale of Suggate (2000, 2002), a technique not affected by suppression. In addition, the oil generation and expulsion thresholds for the CTB coals were investigated, with discussions on oil potential versus marine influence upon the mires in which the coals formed. A pseudo-van Krevelen diagram shows that the majority of the coals plot on the Type II kerogen line, while the remainder plot between the Types II and III kerogen lines, with HI between 151 and 410 mg HC/g TOC; however, Maceral Analysis shows that Type III kerogen predominates. This is attributed to the presence of abundant fluorescing (oil-prone) vitrinites. The LoVR, Tmax and Rank(Sr) parameters all show that maturity increases from basin margins towards basin centre (i.e. from Bassen to Lunckefjellet, to Breinosa and Colesdalen) and indicate that all the coals are within the oil generation window. The marginal samples at Bassen are within the early mature stage of the oil window (i.e. ~ 0.7% RO); meaning the threshold for oil generation in the basin could not be clearly defined. However, the observed maturation trend somewhat parallels the maturation pathway of the New Zealand Coal Band (NZ Coal Band) and the “envelope” of the Sykes and Snowdon (2002) NZ coal data-set; therefore, it is considered that the oil generation threshold for the CTB coals is likely at Rank(Sr) ~ 9–10, Tmax ~ 420–430 °C in line with the observed rise in Bitumen Index (BI). Some of the Lunckefjellet coals and all the Breinosa and Colesdalen coals have either reached or progressed beyond the threshold for oil expulsion as indicated by the peak in HI at Rank(Sr) ~ 11–12, LoVR ~ 0.75–0.85% RO, Tmax ~ 430–440 °C. The peak in BI at Rank(Sr) ~ 12.5–13.5 suggests that some of the Lunckefjellet and Breinosa coals, and all the Colesdalen coals have reached the “effective oil window”. Total sulphur (ST) contents range between 0.46 and 12.05% indicating non-marine to strong marine influence upon precursor peats, with ST contents of the Longyear seam appearing to record instances of coastal retreat associated with base level rise. Marine deposition seems to significantly control the distribution of oil-prone coals within seams and across the CTB. The levels of marine influence (as indicated by ST content) show clear positive relationships between BI and HI within the Bassen samples because they have not started expelling oil. Conversely, the levels of marine influence show clear negative relationships with BI and HI within the Colesdalen samples because they have commenced oil expulsion, and probably reached the “effective oil window”. The more marine influenced coals appear to have commenced petroleum generation relatively earlier, which is a plausible explanation why the coals from the Lunckefjellet locality appear to be at different stages within the oil window.
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geochemistry and petrology of palaeocene coals from spitsbergen part 1 oil potential and depositional environment
International Journal of Coal Geology, 2015Co-Authors: Chris Marshall, Colin E Snape, David Large, Will Meredith, Clement N Uguna, Baruch Spiro, Alv Orheim, Malte Jochmann, Ikechukwu Mokogwu, Yukun WangAbstract:Abundant oil prone coal (Type III kerogen) deposits are preserved within the high latitude, middle Palaeocene, Todalen member of the Central Tertiary Basin, Spitsbergen Island, Norwegian Arctic. The coals (Svea, Longyear, Svarteper and Askeladden seams) have been subjected to only minor previous geochemical characterisation. Focussing upon the Longyear seam, this paper characterises the present, prospective and economic oil potential of the Svalbard coals. Organic biomarker parameters, Fe–S chemistry and coal Maceral Analysis are then applied to understand the provenance and environmental origins of this unusual source rock. The upper Todalen Mbr. coals (Longyear, Svarteper and Askeladden seams) have significantly more oil potential than the Lower Svea seams with estimated retortion yields of 170–190 kg/tonne vs. 24 kg/tonne respectively. The Longyear seam exhibits relatively high HI values (ca. 300–400 mg/g TOC) consistent with a hydrogen rich mixed Type II/III kerogen source. Greatest oil potential is shown to be favoured by formation within a fen environment, with high bacterial degradation (> 100 μg/g TOC hopanes), marine influence (> 0.5 wt.% sulfur, Fe/S < 0.9) and the unique temperate high latitude Palaeocene climate of Svalbard leading to preservation of hydrogen rich organic matter via organo-sulfur bond formation.
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the structure and reactivity of density separated coal fractions
Fuel, 1999Co-Authors: A Gilfillan, Michael Cloke, Edward Lester, Colin E SnapeAbstract:Density separations of six world coals have been carried out. The coals were provided as pf samples and were screened to provide size fractions at -38 + 20 μm from which tight density fractions (0.02 and 0.03 g cm -3 intervals) were produced in a heavy liquid medium using the float-sink procedure. Each density fraction was characterised by manual Maceral Analysis and a new automated image Analysis technique called the reactivity assessment program. The chemical structure of each fraction was examined by 13 C n.m.r. and FT-i.r. spectroscopies. The reactivity of the density fractions was assessed using a drop tube furnace at a temperature of 1300°C, residence time of 100 ms and 1 vol% oxygen atmosphere. The morphology of the chars produced in the drop tube furnace were examined manually and using an automated image Analysis technique. This allowed the predicted reactivity of the fractions to be correlated against actual burnout characteristics.
Ralf Littke - One of the best experts on this subject based on the ideXlab platform.
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organic petrology and geochemistry of triassic and jurassic coals of the tabas basin northeastern central iran
International Journal of Coal Science & Technology, 2019Co-Authors: Nazanin Zamansani, Ralf Littke, Mohammad Ali Rajabzadeh, Laura Zieger, Alireza BaniasadAbstract:Jurassic and Triassic coals and organic matter-rich shales of the Tabas Basin, Iran, were investigated with respect to their thermal maturation and petrographic composition. The Triassic coals of the Parvadeh coal field range in vitrinite reflectance between 1.17% and 1.37% and the Jurassic coals of the Mazino coal field between 2.08% and 2.29% VRr. Maceral Analysis revealed a predominance of vitrinite in all samples, with slightly higher percentages of inertinite in the Jurassic samples. Rock–Eval analyses confirm the presence of type III kerogen in the Triassic coals, while the Jurassic coals contain strongly carbonized residual kerogen. The range of sulfur contents for coals from the Parvadeh coal field (0.37% to 4.64%) and Mazino coal field (0.45% to 2.92%) is related to the effect of marine water in peat. The studied samples are characterized by the predominance of short- over long-chained n-alkanes. The relatively high Pr/Ph ratios indicate predominance of terrestrial organic matter whereas Pr/n-C17 and Ph/n-C18 ratios prove oxic conditions during deposition. In addition, the DBT/Phen ratio shows that these coals formed in fluvial/deltaic environments. Molecular geochemical parameters such as carbon preference index (CPI, 0.99–1.04), methyl phenanthrene index (MPI, 1.20–1.60), methyl naphthalene ratio (MNR, 1.61–3.45), and ethyl naphthalene ratio (ENR, 4–6.78) confirm the high maturity of the samples. Burial and thermal history reconstruction indicates necessity of an erosional thickness of about 4000 m in the Parvadeh area. Towards the Mazino area, a higher basal heat flow up to 80 mW m−2 is assumed for the Paleogene leading to higher maturities.
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petrographical and geochemical characterization of lignites sub bituminous coals and carbonaceous sediments from the erin formation southern basin trinidad implications on microfacies depositional environment and organic matter alteration
International Journal of Coal Geology, 2016Co-Authors: Anastasia A Baboolal, Ralf Littke, Brent Wilson, Alexander T Stock, Joscelyn KnightAbstract:Abstract The Pleistocene tropical lignites of the Erin Formation of southern Trinidad, western tropical Atlantic Ocean, as well as the overlying and underlying sedimentary strata, are here for the first time studied using organic petrological and organic geochemical methods. Six vertical sections were sampled at Granville and South Chatham. The mean huminite (vitrinite) reflectance of the low rank coals and carbonaceous shales at Granville increases through the sections from 0.26–1.05%, indicating a coalification path from lignite to sub-bituminous and even high volatile bituminous coal. This strong increase of reflectance is by no means related to deep burial but to surface-near sweltering, possibly related to self-ignition. Pyrites are strongly oxidised in the thermally altered Granville samples. At South Chatham, all the coals are characterized by low reflectance values (0.15–0.39%) and can be classified as lignite. Pyrite is fresh and sulphur contents are partly high. High sulphur contents at South Chatham might be due to exposure to seawater through transgressive processes during peat deposition or at an early diagenetic stage in a tidal, coastal environment. Maceral Analysis showed the coals at South Chatham to be dominated by huminite (86–97%), with less abundant inertinite (2–12%) and sparsely occurring liptinite (0–2%). The distribution of coal facies based on critical Macerals such as humodetrinite and humocollinite suggests formation of these lignites in a reed marsh to wet forest swamp, exhibiting transition into an upper to lower delta plain environment. Similar conclusions are deduced from tissue preservation, gelification, groundwater and vegetation indices of the coals indicating that they are composed predominantly of small herbaceous plants.
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geochemical and petrographic characterization of campanian lower maastrichtian calcareous petroleum source rocks of hasbayya south lebanon
Marine and Petroleum Geology, 2015Co-Authors: Bou S Daher, Fadi H Nader, Carla Muller, Ralf LittkeAbstract:Abstract Santonian–Paleocene marls and fine grained carbonates have been sampled in Hasbayya locality, south Lebanon, in order to evaluate their organic matter (OM) content, petroleum source rock potential, and assess their depositional environment. Methods included total organic carbon (TOC), total inorganic carbon (TIC), total sulphur (TS), Rock-Eval pyrolysis, organic and inorganic petrography, X-ray fluorescence (XRF), gas chromatography–mass spectrometry (GC–MS) and Curie-point-pyrolysis-gas chromatography–mass spectrometry (CP-Py-GC–MS). TOC, Rock-Eval, and vitrinite reflectance (VRr) results reveal excellent immature petroleum source rocks within the Campanian–lower Maastrichtian interval with TOC up to 11.6 wt%, hydrogen index (HI) up to 872 mg/gTOC, Tmax up to 433 °C and VRr average of 0.36%. Biomarker ratios and Maceral Analysis suggest a marine depositional environment with a dominance of algal as well as submicroscopic OM. Original sediment composition and redox sensitive geochemical parameters suggest deposition of the OM rich intervals under an oxygen minimum zone (OMZ) that was emplaced and controlled by primary productivity and nutrient supply. Pyrolysate composition shows an important content of organic sulphur compounds (thiophenes) increasing with TOC and thus indicating the presence of Type II and Type IIS kerogen in the analysed sample set, which is consistent with the presence of immature solid bitumen in the Hasbayya region. The data produced in this study, coupled with regional correlations, allow us to construct a conceptual depositional model for the Upper Cretaceous OM rich rocks of the eastern Mediterranean suggesting deposition under a productivity belt localized along the inner and outer shelf leading to a decrease in source rock quality and a shift in kerogen type toward the deeper parts of the Levant Basin.
A Gilfillan - One of the best experts on this subject based on the ideXlab platform.
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the structure and reactivity of density separated coal fractions
Fuel, 1999Co-Authors: A Gilfillan, Michael Cloke, Edward Lester, Colin E SnapeAbstract:Density separations of six world coals have been carried out. The coals were provided as pf samples and were screened to provide size fractions at -38 + 20 μm from which tight density fractions (0.02 and 0.03 g cm -3 intervals) were produced in a heavy liquid medium using the float-sink procedure. Each density fraction was characterised by manual Maceral Analysis and a new automated image Analysis technique called the reactivity assessment program. The chemical structure of each fraction was examined by 13 C n.m.r. and FT-i.r. spectroscopies. The reactivity of the density fractions was assessed using a drop tube furnace at a temperature of 1300°C, residence time of 100 ms and 1 vol% oxygen atmosphere. The morphology of the chars produced in the drop tube furnace were examined manually and using an automated image Analysis technique. This allowed the predicted reactivity of the fractions to be correlated against actual burnout characteristics.
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the characterization of coals and density separated coal fractions using ftir and manual and automated petrographic Analysis
Fuel, 1997Co-Authors: Michael Cloke, A Gilfillan, Edward LesterAbstract:Abstract In the first part of this study density-separated, coal fractions of Point of Ayr coal were analysed using petrographic techniques and infrared (IR) spectroscopy. Density separations were carried out on the 38 + 20 μm size fraction using sodium polytungstate as the dense liquid medium. Petrographic Analysis and FTIR Analysis, using the diffuse reflectance technique, were carried out on the density-separated fractions. For the FTIR Analysis the samples were micronized to give a particle size of 2 μm which leads to a considerable improvement in the quality of the recorded spectra without the need for dilution with potassium bromide. Area measurements of the aromatic ( A Ar ) and aliphatic ( A Al ) CH stretch absorptions together with area ratios of these absorptions ( A Ar / A Al ) were determined for each of the density fractions and the feed coal. The A Ar / A Al ratios showed an increase with higher density, indicating a change in aromaticity as the density of the fractions is increased. A linear correlation between the area ratios and major Maceral Analysis was found. The results of this part of the study thus showed that changes in the IR spectrum could be directly related to the Maceral composition, and that the diffuse reflectance technique could be used to obtain consistent good quality IR spectra of powdered coals. Using the same FTIR technique the A Ar / A Al ratios of 29 world coals was found and correlated with Maceral analyses of the coal, Maceral Analysis plus rank and the grey-scale histogram produced during automated, petrographic Analysis of the coals using image Analysis. A poor correlation was obtained between Maceral Analysis and the A Ar / A Al ratio. The correlation improved markedly when rank was included, but the best correlation ( R 2 = 0.96) was obtained against the grey-scale histogram. This work indicates that it may be possible to use the diffuse-reflectance FTIR technique as a rapid characterization technique for coal reactivity.
