Coal Extract Solution Research Articles

Polyurethanes derived from coal extract

ABSTRACTSubbituminous coal from the powder river basin was extracted with N,N‐dimethylformamide at atmospheric pressure to yield a solid extract that provided phenolic and carboxylic acid groups. The coal extract was employed as polyol in polyurethane (PU) synthesis. A solvent‐free synthesis using 2,4‐toluene diisocyanate (TDI) resulted in a porous PU solid. Reaction with TDI in solution resulted in a soluble PU that could be applied as adhesive or coating. Coatings were also prepared from coal extract solutions and commercial, polymeric isocyanates, providing excellent adhesion to aluminum. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48776.

Investigation of Association in Coal Extract Solution by the Measurement of Relative Viscosity

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTInvestigation of Association in Coal Extract Solution by the Measurement of Relative ViscosityMasaharu NishiokaView Author Information 19069 McFarlin Drive, Germantown, Maryland 20874 Cite this: Energy Fuels 2001, 15, 5, 1313–1316Publication Date (Web):July 13, 2001Publication History Received21 February 2001Published online13 July 2001Published inissue 1 September 2001https://doi.org/10.1021/ef010041wCopyright © 2001 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views62Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (43 KB) Get e-AlertsSUBJECTS:Absorption,Coal,Pyridines,Solvents,Viscosity Get e-Alerts

99/01888 Effect of precipitating some of the more intractable material from a hydrogen-donor solvent coal extract solution on its hydroprocessing behavior: Martin, S. C. et al. Energy Fuels, 1998, 12, (6), 1228–1234

99/01888 Effect of precipitating some of the more intractable material from a hydrogen-donor solvent coal extract solution on its hydroprocessing behavior: Martin, S. C. et al. Energy Fuels, 1998, 12, (6), 1228–1234

Effect of Precipitating Some of the More Intractable Material from a Hydrogen-Donor Solvent Coal Extract Solution on Its Hydroprocessing Behavior

In view of the fact that the Ni/Mo γ-alumina catalysts currently used deactivate rapidly during coal liquids hydroprocessing, the feasibility of removing the more intractable material from a typical coal extract solution prepared with hydrogenated anthracene oil (HAO) was examined by precipitation with toluene both prior to and after filtration. The reductions in total conversion to pyridine solubles of only 3-4% achieved were accompanied by a decline of nearly 50% in the THF-insoluble concentrations for the modified extract solutions. As the amount of toluene added to approximately 1 kg of the coal/HAO digest was reduced below 300 cm 3 , the ash contents of the resultant filtered extract solutions increased toward the normal concentration of ca. 0.03% obtained without precipitation. Batchwise and continuous hydroprocessing tests conducted on the normal and modified coal extract solutions with a commercial Ni/Mo γ-alumina-supported catalyst demonstrated that the lower concentrations of THF insolubles gave rise to significant improvements in conversion for the n-hexane, toluene, and THF insolubles in the feeds. In accord with their higher surface areas and lower carbon contents, the HDS activities of catalyst samples recovered from a continuous run with feed modified by toluene addition were considerably higher than those for the corresponding samples for the normal feed.

97/02538 Small angle neutron scattering studies of coal-extract solutions

Interest in the physics and chemistry of coal extracts has extended for over 100 years. Early on it was recognized that pyridine was a particularly good solvent capable of extracting a significant weight percent of intermediate rank coals. Many of the current theories regarding the macromolecular structure of coals (type III kerogens) are based on the fact that there exists a physically definable limit in the extractability of soluble organics from coal in pyridine. The non-extractable residue is generally considered to be a cross-linked macromolecular network. The extract-solvent {open_quotes}solutions{close_quotes}, although acknowledged to be far from ideal (thermodynamically), are presumed to be {open_quotes}molecular solutions{close_quotes} in the sense that random mixing of the constituents occurs within a single solution phase. This research set out to characterize the solution structures of coal extracts to gain insight into the nature of coal-solvent interactions.

Surface Tension of Coal Extracts in Organic Solvents

In this study, two Argonne premium coals were extracted with CS 2 -N-methyl -2-pyrrolidinone mixed solvent and the surface tensions of coal extract solution were measured

Trace element reduction in coal extract solutions

The ash content, after filtration, of coal extract solutions produced using two different coals and two different samples of hydrogenated anthracene oil (HAO), and the consequential effect of varying digestion pressure and filtration temperature have been studied. It was found that if the digestion pressure is above 3.0 MPa, then the extract solution ash level is reduced significantly. However, this effect is modified by the coal or HAO used. This can be allowed for by reducing the filtration temperature for a given system. The condensed material vented during digestions was analysed, and it was found that there was no significant difference in the components present for different digestion pressures, only that a greater quantity was given off during lower pressure digestions. The vented material from low-pressure runs was added back to the digest prior to filtration, but it was found that this did not give low-ash extracts similar to those produced at higher pressure.

Evidence for trace element forms of titanium and manganese in coal liquefaction extract solutions

The trace element contents of the insoluble portions of a filtered coal extract solution treated with pentane, toluene and THF were determined using atomic absorption spectroscopy (a.a.s.) and atomic emission spectroscopy (a.e.s.). In all cases a large proportion of the trace elements were found in the insoluble portion, but there were no significant differences between the individual trace elements. Further experiments were carried out in which TiO 2, MnCO 3 and low temperature ash were added to normal digestions of coal in hydrogenated anthracene oil (HAO), and were also digested in HAO only. The filter cakes produced in the latter experiments were redigested in fresh HAO a second and third time. The results strongly indicate that Ti passes through the filtration stage of the liquefaction process as finely-divided mineral matter. Mn, however, undergoes some change during the process which enables it to pass through the filtration stage.

Evidence for mineral matter forms in coal liquefaction extracts

High- and low-temperature ashes from feed coal, coal extract solution and filter cake from a two-stage coal liquefaction process have been studied by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray fluorescence (SEM/EDX). Hydrocracking experiments using alumina support only, in place of the active Ni Mo catalyst on alumina, were also carried out, with trace metal analysis of the coal extract solution feed and hydrocracked extracts using atomic absorption and emission spectroscopy. The major mineral transformations occurring were of pyrite to pyrrhotite and the fixation of organic sulphur by calcium carbonate. Mineral particles were not observed in the coal extract solution ashes, even under high magnification, and the study indicated that size alone was not a determining factor as to whether a coal mineral was to be found in a coal-derived liquid. None of the trace metals was deposited on the alumina support under hydrocracking conditions, in marked contrast to the results obtained with the normal Ni Mo catalyst. These results lead to the conclusion that for the deposition of trace elements to occur a reaction must take place and hence the trace elements must be chemically bound in some form.

Changes in trace element concentrations and catalyst activity during the hydrocracking of a coal extract solution

A hydrocracking rig has been constructed which involves the passing of coal-derived liquids and hydrogen over a trickle bed packed with a nickel oxide/molybdenum oxide catalyst. The ash and trace metal levels have been measured, before and after hydrocracking, and their variation with catalyst lifetime has been assessed. Al, Ca, Fe, Mg, Mn, K, Si, Na and Ti levels have been determined by a.a.s. and considerable reductions have been observed for Fe, Mg, Mn and Ti after hydrocracking. The ash level of hydrocracked extract increases for the first 50 h and then stabilizes at about 60% of the feed level. Metal levels determined for the catalyst itself show an accumulation of all the metals under consideration, especially for the sections of the catalyst which were hottest. Overall catalytic activity is not seen to decrease markedly but the ability of the catalyst to produce lower boiling material is considerably reduced after only 25 h. Comparisons between catalyst activity and metal deposition are made.

Small-angle neutron scattering study of coal extract solutions in pyridine

Three perdeutero-pyridine extracts of Illinois No. 6 coal were studied with SANS in an effort to: 1. check the reproducibility of the measurements; 2. check the reproducibility of the extractions; and 3. try to measure weight average molecular weights for the non-fractionated extracts. In addition one sample from the Bruceton mine of Pennsylvania was studied to check any dependence on the coal's origin and one silylated sample of an Illinois No. 6 extract was studied to assess the effect of chemical treatment of coals on the average molecular weight. The chemical composition and the number-average molecular weights were obtained for the same samples. Scattering data were observed to be well represented by the Debye theory for a random two phase system with an experimental density-density correlation function described by a correlation length a. The analysis of the data shows that the extraction is a non-reproducible operation and this seems to be due to the heterogeneous nature of coal. In addition the present methods available to obtain molecular weights from the scattering data do not seem to be applicable to coal extracts.

Hydrogen donor and acceptor abilities of pitch: 1H n.m.r. study of hydrogen transfer to anthracene

Petroleum pitches, coal-extract solutions and hydrogenated coal-extract solutions are co-carbonized with anthracene at 673 K. Chloroform-soluble fractions of the system are monitored by 1H n.m.r. for formation of 9.10 dihydroanthracene (DHA). A hydrogenated coal-extract solution is also co-carbonized at 673 K with anthracene together with thianthrene and sulphur. Ashland A240 petroleum pitch and anthracene are co-carbonized with hydrogenated anthracene oil and resultant 1H n.m.r. spectra are analysed for DHA. The pitches and coal-extract solutions are carbonized to 823 K and the optical textures of resultant cokes are assessed by optical microscopy. The purpose of the study is to assess if pitches which form cokes with larger optical textures or have greater abilities to modify the carbonization behaviour of coals also have the ability to act as ‘hydrogen shuttles’ in the carbonization system. Results would indicate that such pitches produce the largest amounts of DHA. It is proposed that the most efficient of the modifying pitches operate by extending the zone of temperature of maximum fluidity and by increasing the value of maximum fluidity by removal by proton transfer of radicals which if left in the carbonizing system would interact to form cokes of smaller optical texture.

Microscopy study of bonding in co-carbonizations between coke grist from coal-extract solution and coal-tar binder

Optical microscopy and SEM examine coke composites from the co-carbonization at 673 K of coke grist (60%) from a coal-extract solution with Orgreave lean coal-tar pitch (40%) to study binding mechanisms. The coke grist was prepared at heating rates of 5–300 K h −1 to HTT of 800 K (one coke to 1200 K). It was found that the bonding was weak or non-existent using coke grist of heating rates 5 and 15 K h −1, but was significant using coke grist of heating rates 75, 150 and 300 K h −1 (except for coke of HTT 1200 K which showed poor bonding). These effects are discussed in terms of surface structure of the coke grist, possible influences of free-radicals (free-spins) and wettability associated with porosity.

Carbonization and liquid-crystal (mesophase) development. 16. Carbonizations of soluble and insoluble fractions of coal-extract solution

Abstract A coal-extract solution prepared by extraction of a coking coal (CRC 301a) with anthracene oil by the National Coal Board is separated into fractions using solvents of increasing solvent power. These fractions are carbonized to 823 K and the optical textures of resultant cokes are assessed. The objective of the study is to examine the role of the molecular components of the coal-extract solution including the residual anthracene oil in mechanisms of formation of the optical texture of the anisotropic coke. Generally, the low-molecular-weight fractions of the coal-extract solution produce cokes with larger sized optical textures than the coke from the parent coal-extract solution. The higher-molecular-weight fractions produce cokes with smaller sized optical textures. Isotropic coke is produced from material which is not soluble in benzene and tetrahydrofuran. Within this parent-coal-extract solution it would appear that the dominant partner effect is influential over the size of the optical texture of coke from the coal-extraction solution, that is the minor component of smaller molecules controls the necessary growth of liquid crystals. Also, the presence of anthracene oil augments the size of optical texture of resultant cokes by providing the necessary physical fluidity of the system and possibly some chemical stability.

Carbonization and liquid-crystal (mesophase) development. 18. carbonization of coal-extract solutions (non-hydrogenated): influence of digestion conditions upon optical texture of cokes

Abstract Coal-extract solutions have been produced by the dissolution of a prime coking coal in anthracene oil followed by the removal of the undissolved solids. A range of coal-extract solutions prepared under different conditions was carbonized and the optical texture of the polished surfaces of the resultant cokes were assessed. The coal-extract solution prepared with the longest digestion time and at the highest temperature produced a coke with the largest anisotropic domains with some flow structure. Removal of the anthracene oil component of the coal-extract solution by extraction with selected solvents modified the carbonization behaviour such that although the coke yield increased substantially there was a significant decrease in the size of the anisotropic domains of the resultant cokes.

Carbonization and liquid-crystal (mesophase) development. 17. Co-carbonization of a solvent-refined coal with petroleum pitches and hydrogenated coal-extract solution

This study characterizes the optical textures of cokes prepared by the carbonization of Ashland petroleum pitches, of non-hydrogenated and hydrogenated coal-extract solutions (CES) and of blends of non-hydrogenated CES materials with the petroleum pitches and hydrogenated CES materials. At an HTT of 823 K petroleum pitches produce cokes with large sized optical texture of flow-type anisotropy characteristic of needle-cokes. The non-hydrogenated CES materials produce cokes with optical textures of mozaics, 2–10 μm. However, following hydrogenation the CES materials carbonized to cokes all of which possess considerable large sized optical textures which for some materials resemble that of needle-cokes by possessing strong flow-type anisotropy, > 100 μm. Hydrogenation of the CES materials evidently facilitates the physical and chemical requirements for growth and coalescence of lamellar nematic liquid-crystals and mesophase from the fluid phase of carbonization leading to anisotropic carbon. Co-carbonizations of the non-hydrogenated and hydrogenated CES materials exhibit the dominant partner effect and are comparable in behaviour with Ashland petroleum pitches which are known to produce needle-cokes on carbonization.

Activity of Ni-Moly catalysts in tetralin or decalin dehydrogenation and in hydrogenation of coal-extract solution

The activity of several NiMoly catalysts in the processes of dehydrogenation of tetralin or decalin and hydrogenation of coal-extract solution has been determined. In both processes studied, the activities of the catalysts investigated have been found to follow rectilinear relations with quantity. It has also been shown that the activity of a NiMoly catalyst can be predicted in hydrogenation of coal-extract solution, from its activity in dehydrogenation of tetralin or decalin; the latter reaction is relatively simple to conduct in laboratory conditions. However, caution must be exercised when very narrow pores, making possible Knudsen diffusion of hydrogen at high pressure, exist in the catalyst.