Geochemical features of hazardous elements and cleaning potential of coal from Xinzhouyao coal mine

01 03/00467 Geochemical features of hazardous elements and cleaning potential of coal from Xinzhouyao Coal Mine Wang, W.-F. et al. Zhongguo Kuangye Daxue Xuehao, 2002, 3 I, (3). 28 l-284. (In Chinese) Based on the analysis and test of 41 elements, the occurrence, mechanism and environmental effect of 19 potentially hazardous elements in samples of coal seam 9 from the Xinzhouyao Coal Mine were discussed. The results show that the hazardous elements S, As, Sb, Se, Co, MO, Pb, Ni, Br, Mn and Be are notably enriched in the seam, and As, Sb, Se, Co, Pb and Ni tend to increase toward the seam roof. The occurrence of As, Sb, Se, MO, Co and inorganic S is mainly related to pyrite, most of which may be removed through physical washing methods. The Br occurs in organic matter and is hard to remove. Organic S has a high content and is potentially hazardous to the environment, so should be removed before use. The potentially hazardous elements in coal seam 9 might be derived from the superposition of the various geochemical origins in which the paracontemporaneous origin might play a leading role. 03/00468 Grey clustering prediction for slagging potential of coal blends combustion Qiu, J. et al. Combustion Science and Technolog~~, 2002. 114, (3), 5 l-70. The ash behaviour and slagging characteristics of several individual coals, different in rank and ash content, and of their two-component blends, were studied by measuring chemical composition, ash fusion temperature, viscosity, and mineral transformation. The experimental results indicate that ash fusion temperatures for various percentages of two different coal blends illustr&e non-arithmetic aieraeiner The fusion slag of base coals affects the viscosity of coa”l vblends. Temperature and atmosphere affect mineral species vaporization. Considering the limitation of single slagging index for prediction, an overall grey clustering model that takes into account the main related parameters such as ash characteristics, mineral transformation, and combustion parameters is proposed to predict the slagging propensity of the blends. The results suggest that the slagging propensity of coal blends from two coals of similar reactivity and slagging potential was similar to that of the individual coals. However, when one coal was blended with another coal with widely different reactivity or slagging potential, the slagging grade of the coal blends changed significantly. The results of slagging experiments in a combustion test furnace were in agreement with those from model prediction. It implies that the proposed overall grey clustering model can predict slagging tendency more accurately than conventional index. Moreover, the predicted results are comparable with that from a practical boiler slagging test. Preliminary study of tectono-thermal evolution 03/00469 characteristics and coalbed methane resource in Huainan coalfield Li, X. el ul. Kuangw Xuehao. 2002, 22, (I), 85-91. (In Chinese) This paper studies tectono-thermal evolution characteristics and coalbed methane resource in the Huainan coalfield by fission track analysis. The results show that: (1) at least three thermal events have occurred since late Paleozoic at ~240 140 and 80 Ma, respectively; (2) paleo-geothermal gradient was higher than that at the present. The study estimated that denudation thickness of the area was >2000 m. On the basis of the characteristics of tectono-thermal evolution of the Huainan coalfield, the preliminary conclusions will be drawn as follows: the first and second tectono-thermal events happened at 240-140 Ma during the Mesozoic, so that most of the coal formed in late Paleozoic was gradually metamorphosed into gaseous one and a minor amount of it into fat coal. Production of coalbed methane was not too much, and the tectono-thermal events in the late Cretaceous led to the release of coalbed methane into the atmosphere. In general, more gas will release from the regions where structures are better developed than that from the regions lacking structures, which may be suitable for the development of coalbed methane. This method may be applicable to coalbed methane exploration and development. Product analysis of catalytic multi-stage hydro03/00470 pyrolysis of coal Li, W. et al. Zhongguo Kuongw Dcluuc Xuehao, 2002, 3 1, (3). 246-25 I. (In Chinese) Multi-stage hydropyrolysis (MHyPy) and hydropyrolysis (HyPy) of Xundian lignite, with MO& as the catalyst, were performed in a fixed bed reactor. The product distribution and property were investigated in detail. The results show that the tar yield increases to 63.9% during MHyPy compared with that of 51.8% in HyPy, while the gas yield decreases by a half. The tar composition does not make big difference between MHyPy and HyPy. However, the light aromatics in the tar from MHyPy increase remarkably by 42%, 37.8% and 115.4% for BTX, PCX and naphthalenes respectively. The specific surface area of char from MHyPy is larger than that from HyPy. The average pore diameter of char from MHyPy is smaller than that from HyPy, while the pore volume increases by 100% compared with that from HyPy. The catalytic MHyPy has an obvious advantage over HyPy.

Solid fuels (sources,

wi,ming,

properties)

Relationship between coal powder and its 03/00471 combustibility Xie, J-L. et al. Journal of Wuhan Universit,, of Tecirnolo,g.v, Matuials Science Edition, 2002, 17, (l), 72-75. Coal’s volatile component, ash and fixed carbon content have different functions in different stages of a combustion process, but the traditional coal classification can precisely show its combustion property. In this experiment coal’s evaluation indexes (ignition index D,, burn off index Df) were used to quality show the ignition property and combustion ending property of coal samples. Meanwhile, considering actual heating circumstances in calciner (in cement plants), this study established the relation among the ignition index, burn off index and coal’s industrial analysis value, which makes it possible for the user to predict the quality of coal before using. 03/00472 Spontaneous ignition of brown coal dust. Experiment, determination of kinetic parameters, and mathematical modeling Amel’chugov, S. P. et ul. Fiziko Goreni1.o I I ‘zrl w. 3003, 38, (3). 48-54. (In Russian) An apparatus and a study of self-ignition and explosion of brown coal dust are described. The kinetic parameters (activation energy and preexponential factor) for Irsha-Borodino brown coal were detected. It was shown that at certain coal/oxidant ratios a two-stage explosion is observed. The repeated explosion is due to the thermal activation of coal at the first stage of explosion. Mathematical models describing spontaneous ignition of brown coal dust were developed. Status and prospects of the use of Ukrainian salty 03/00473 coal in power generation. Review Dunaevs’ka, N. I. et al. Ekotekhrzologii i Re.\l~r\otber lc~:iwtzic~. 2002. (3), 29-33. (In Ukrainian) The estimated salty coal deposits of Bogdanovsk, Novomoskovsk, and Petrikovsk are in the range of 10 billion tons. The characteristics of this bituminous coal are suitable for use in thermal powj,:r plants. 03/00474 The effect of coal type in dry-sorbent/coal injection for control of SOa and NO, emissions Levendis, Y. A, and Ergut, A. Proceedings of the International Technical Conference on Coal Utilization & Fuel ‘Y.l.\trmj, 2002, 2, (27), 875-885. (In Japanese) Simultaneous reduction of NO,, SO?, and particulate emissions from power plants is achieved by a method combining injection of sorbent/ coal blends with a ceramic honeycomb filter. The filter is mounted in an elevated temperature region where it retains sorbent particles for prolonged periods of time and facilitates their utilization until it is eventually regenerated (cleaned). This filter also captures and oxidizes particulate C, which otherwise might contribute to the formation of air toxics, e.g. dioxins, as the effluent cools further Performance of composite sorbents, such as CaC03 and NaHCO;. and the porous sorbent calcium formate was evaluated in the laboratory. Sorbent powders were blended with three types of pulverized coal to achieve NO, reduction, i.e. bituminous, sub-bituminous, anti lignite. Sorbent/ coal blends were injected in a simulated effluent gas containing SO2 and NO at a gas temperature of 1150” (1423 K), upstream from a ceramic filter, which was maintained at 600 (X73 KI. The molar Ca:S ratio was -2, and the fuel:air equivalence ratio. (.>,was also ~2 (fuelrich) for all tests. Emphasis was placed on differentiating the effect of coal type on reducing SO2 and NO, emission concentrations. Results showed SOZ removal efficiency of 35-80% was achieved, depending on coal type and sorbent used. NO, reduction efficiency of 45-55% was obtained, depending on coal type. Particulate removal efficiency by the filter was measured at 97-99%. The effects of pressure on coal reactions during 03/00475 pulverised coal combustion and gasification Wall, T. F. et al. Progress in Energy und Comhustiol? s’(icww. 2002, 28, (5), 405-433. Advanced clean coal technologies, e.g. power generation from integrated gasification combined cycle (IGCC) and pressurized fluidized bed combustor, have attracted increased Interest from the scientific and technological communities over the last few decades. Pressures up to 40 atm have been applied to these technologies, which inherently result in an increase in coal throughput, a reduction in pollutant emissions and an enhancement in the intr:n5ity of reaction. Therefore, fundamental understanding of the eftect of operating pressure on coal reactions is essential to the development of these technologies. In this paper, the pressure effect on a variety of aspects of coal reactions reported in the open literature has been reviewed. Major emphasis of the paper is given to experimental observations, although some theoretical modelling is reviewed. The pressure has been found to significantly influence the volatiles yield and coal swelling during devolatilization, hence the structure and morphology of the char generated. More char particles of high porosity are formed at higher pressures. Char structure appears to play a significant role in burnout Fuel and Energy Abstracts

May 2003

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