0 1 Solid fuels (sources, winning, properties)

97102524 Model FJ-2821 ?-ray ash monitor and its application Zhang, Q.er ul. Yejin Fenxi, 1996, 16, (4). 37-38. (In Chinese) A FJ-2821 -,-ray ash monitor was used to determine coal ash with good precision. The effects of moisture content, particle size, degree of compactness and types of coal on the determination were studied.

97102525 Multivariant statistical methods for examination of trace element distribution in Ruhr coals in Germany Schroeder. R. et al. Glueckauf-For.~chungsh., 1996, 57, (4), 145-151. (In German) The bonding environment of trace elements in German coals was investigated through multivariant statistical analysis. Both low- and high- ash outputs from a laboratory flotation were subjected to the elemental analyses and radiochemical phase analyses to establish mineral content. The geochemical character of the trace elements was described using main- component analysis, and then the clay mineral, sulfide, and heavy mineral factors were deduced. Cluster analysis in the Q-mode yielded a separation according to the stratigraphy, whereas the R-mode provided an agglomera- tion according to the geochemical character of the trace elements.

97102526 Nature and distribution of phosphorus minerals in Cook inlet coals, Alaska Rao, P. D. and Walsh, D. E. lilt. J. Coal Ceol., 1997, 33, (1) 19-42. Phosphorus concentration in coal is generally low, ranging from O.nOl% to 0.229% in raw coals of the contiguous 4X states of the U.S.A. Some Alaskan coal\ in the Cook Inlet region contain horizons unusually high in phosphorus. Analyses of coals at 0.3 m intervals from a deep drill core, containing 21.3 m of sub-bituminous C coal from the Beluga coalfield, Alaska, showed certain increments with as much as 17.03% P:Os in the coal ash; 1.01% P on a moisture-free coal basis. Crandailite-group minerals were identified by electron microprobe analyses as phosphorus-rich minerals in these coals. Due to high phosphorus horizons in Cook Inlet coals attrihutahle to periodic infusions of phosphorus from volcanic ash. as well as the proper chemical environment for the precipitation of the phosphorus minerals, it is suggested that the profiles of acid extractable phosphorus concentration may he useful to aid coal seam correlations.

97102527 15N CPMAS NMR of the Argonne premium coals Solum, M. S. et trl. Ener&q, ~uelr. 1997, I I, (2). 491-494. Arguments arc presented to explain discrepancies between observations and conclusions obtained from NMR experiments and those obtained hy XPS and XANES techniques. Detectability of different types of nitrogens is discussed in terms of cross-polarization dynamics together with the effects of the large chemical shift anisotropy that is found in different types of nitrogen functional groups. Data on acid-treated coals confirm the presence of pyridinic type nitrogens that were not ohserved in a previous “N NMR study of coals.

97102528 New approach to coal structure through its evoiu- tion during dry catalytic hydrogenation Mastral. A. M. ~‘f al. Energy Fuels, 1997, 11, (2), 483-490. Hydrogenation experiments were performed in tubing bomb reactors, in the absence of solvent, with an initial pressure of 10 MPa of H?, and for a reaction time of 30 minutes. The catalyst precursor was iron sulfide. Different techniques were implemented to characterize the solid residues. These include solvent swelling in pyridine and surface and porosity studies. Textural characterization showed that there is a relationship between the increase of the skeletal density and chain length; the structure becomes more compact and ordered in the absence of low molecular weight or non- covalently honded material.

97102529 Nitrogen distribution in a fixed bed pyrolysis of coals with different ranks: formation and source of NZ. wo, 2. El al. Energy Fuels, 1991, 1 I, (2) 477-482. The author describes an experiment in which 16 coals from brown to bituminous coal were pyrolysed in high-purity He with a fixed bed reactor, and the nitrogen distribution was examined. The results indicate that Nz originates mostly from char nitrogen and/or precursors. The mechanism of Nz formation is discussed mainly in terms of the catalysis of solid phase reactions by Fe-containing minerals in low-rank coals.

97102530 On a possibility to determine the content of clay minerals hydration water in solid fossil fuels Urov, K. and Keel, M. Proc. ESI. Acad. Sci., Chcnz. 1996, 45, (3-4), 107- 113. High-performance thermogravimetry showed the water of hydration of clay minerals in the mineral portion of fossil fuels forms a well-defined peak at 520-580°C. This method can also be used for estimating the content of this type of water in argon-rich rocks. This thermogravimetry peak overlaps the decomposition of mineral carbonates to CO:,(at 629-770°C). The content of water of hydration in the non-carbonate mmeral portion of solid fuels is not constant and has a tendency to decrease with increasing content of non- carbonate minerals.

97102531 Possibilities of petrographic analysis methods under modern conditions of coking feedstock resources of Russia Ol’shanetskii, L. G. Koks Khim. 1996, (ll), 2-9. (In Russian) An evaluation of various methods for the determination of the rank composition of coal concentrates based on their vitrinite reflectance.

97102532 A preliminary study on the nature of coal in Siari area of East Bokaro Coalfield Maitra, A. et al. Fuel Sci. Technol., 1995, 14, (2), 55-61. Through seam characterization of the Siari Block of East Bokaro Coalfield their prime coking character is revealed. It may he used for metallurgical coke making after heneficiation.

97102533 Quantitative evaluation and comparison of the thermal properties of coals by dimensionless analysis Adonyi, Z. et al. Permd. fo/yrech., Chem. Eng., 1995, 39. (2) 101-l 17. The paper states that the I, = E,/RT, dimensionless evaluation is suitable for describing TG measurements according to the E,/RT, = In A + n[ln (-o),]-In (doidt) equation. It is applicable for the examination of coals.

97102534 Quantitative relation between the macromolecular characteristics of brown coal and its reactivity in conversion with Tetraiin Kuznetsova, P. N. Fuel, 1997, 76, (2), 189-193. The author states that the reactivity of Kansk-Achinsk hrown coal in thermochemical conversion with Tetralin is a linear function of the macromolecular network flexibility. This is primarily controlled by ionic crosslinking with carhoxylate bridges via polyvalent cations such as Cc’+. Once strong crosslinks have been removed by treatment with HCI or by methylation, minor thermal activation resulted in enhanced swelling hy Tetralin. The degree of swelling of ion-exchanged coal in Tetralin could he linearly related to the content of incorporated divalent metal. Similarly. the degree of conversion (liquefaction) in Tetralin could he linearly related to the degree of coal swelling hy Tetralin.

97102535 A question concerning coal structure andlor reac- tivity. The reaction of maieic anhydride with Pittsburgh No. 8 coal Larsen, J. W. ct al. Prep. Pap. Am. Chem. Sm.. Div. Fuel C‘lwm.. 1997. 42. (I). 185-188. The reaction of maleic anhydride with coals under Diels-Alder conditions has been carried out using “C lahelled maleic anhydride and Pittsburgh No. 8 coal. The results are consistent with the occurrence of the Dicls- Alder reaction. There is evidence against the occurrence of all other conceivable reactions. The amount of maleic anhydride incorporated is inconsistent with all published coal structures. The authors conclude that either coal structures are seriously in error by omitting a significant population of reactive diene structures or coal reactivity is strongly enhanced by mechanisms not yet understood.

97102536 Recent studies on coal structure Yamada. 0. Shigm to Kankyo, 1996, 5, (6), 349-357. (In Japanese) The paper presents a two-phase model based on the idea that coal is a three-dimensionally cross-linked macromolecular network. This model has heen used to discuss the molecular structure of coal and various coal conversion reactions. Recent studies on coal structure indicate the importance of non-covalent interactions in coal. An associated model for coal structure has also been proposed. Pore structure of coal is claimed to consist of separate closed pores. Small angle neutron scattering studies indicate no micropore structure in coal. Novel approaches to the problems in traditionally approved concepts of coal structure were reviewed.

97102537 Recovery of fine coal from coal preparation plants and tailings ponds by selective oil agglomeration Hoare, I. C. et al. Proc. Annu. Int. Pimhurgh Cm/ Conf., 1996, 13, (2). 1392-1398. The expense of oil agglomeration means it has been neglected as a candidate for fine coal recovery. A source of low cost rejects oil, not previously utilized, was used successfully as an agglomerating agent in lahoratory studies and favourahle economics have been demonstrated. High yields of reduced ash coal have been obtained, with low oil to coal loadings. The oil is abundant, low in S, ash and heavy metals. and has a low toxicity. Effective utilization of the oil required the development of a suitable emulsion chemical, capable of handling the changing properties of the various feeds. With successful development of the process in the lahoratory, a PDU scale up followed, incorporating a number of novel ideas. The laboratory studies, PDU studies and pilot plant are discussed and an economic assessment of the PDU presented.

Fuel and Energy Abstracts July 1997 211