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971.
972.
973.
974.
燃煤电厂是最主要的人为汞排放污染源,氯元素对汞的形态转化及脱除率有非常重要的影响。本文概述了燃煤电厂汞的释放特性和现有控制技术,从氯元素作为烟气组分、活性炭改性物以及燃料添加剂这3个方面详细阐述了氯对汞排放控制的影响。首先氯化氢作为烟气组分,对单质汞向氧化态汞的形态转化有促进作用,这有利于现有除尘、脱硫装置对烟气汞的脱除。含氯化合物改性活性炭吸附剂时,物理吸附和化学吸附同时存在,这能有效提高吸附剂对汞的吸附性能。氯化物作为燃煤添加剂也能有效促进烟气汞的氧化和脱除,其中氯元素在湿法脱硫废水中富集,如何把其利用到烟气汞的脱除对开发高效脱汞技术有重要的意义。同时,比较了以上3种氯添加方案的优缺点。最后指出,深入研究氯元素对汞作用机理是今后的研究方向。 相似文献
975.
概述了中国动力配煤技术的研究与应用及发展前景,总结分析了山西地方煤炭运销系统动力配煤技术的应用、现状及实现产业化的发展前景,指出了山西地方煤运系统动力配煤实现产业化需研究和解决的一些问题。 相似文献
976.
由下行床热解和提升管(或输送床)气化组合形成的流化床两段气化将煤气化反应过程解耦为煤热解和半焦气化两个反应阶段,热解产物完全进入气化反应器,利用其中的高温环境和输送的半焦催化作用分别实现焦油的热裂解与催化裂解,完成低焦油气化。利用该流化床两段气化的10 kg/h级实验室工艺实验装置,以榆林烟煤为原料、水蒸气/氧气作为气化剂,变化过量氧气系数ER、蒸汽炭比S/C、热解及气化温度等参数,研究水蒸气/氧流化床两段煤气化制备低焦油合成气的特性。结果表明,流化床两段气化系统可实现稳定运行(实验3 h以上),在ER=0.36和S/C=0.15时,热解和气化的代表温度分别稳定在735℃和877℃,合成气的CO、CO2、H2、CH4、C n H m 和N2含量分别为14.33%、10.07%、18.39%、9.89%、1.82%和45.50%,相应的合成气产量达到1.8 m3/kg,低位热值8.99 MJ/m3,焦油含量0.437 g/m3,展示了制备低焦油合成气的技术特征。对于实际的长时间连续运行,更高的气化温度将使流化床两段气化具有更好的低焦油特性。 相似文献
977.
F.R.Ludwig Schoening 《Fuel》1982,61(8):695-699
It has been shown that the interatomic distance of ≈0.43 nm in coal is predominantly due to turbostratic-graphitic order. The height of the corresponding peak in the G(r) function which is the Fourier transform of the properly corrected and normalized X-ray diffractogram, has been investigated as a function of the concentration of volatile matter and the heat treatment of the coal. The results clearly show that this new parameter which is based on the whole diffraction pattern, is a useful aid in the study of coal, in particular when the structural changes within one coal are investigated. 相似文献
978.
A computer controlled scanning electron microscope fitted with soft X-ray fluorescence analysed thousands of pulverized coal particles in the size range 10 to 100 μm for amounts of Al, Si, Ca, S and Fe in each of the particles. Two coals were used, namely, subbituminous C, Comanche-Wyoming and subbituminous B, Rosebud-Montana. In pulverized coal combustion Rosebud coal has a bad slagging record not predictable from conventional slagging indices based on the elemental analyses of the total coal ash. The coal particles were placed into one of four groups: little mineral matter; low melting point inorganic composition; high melting point compositions; and large amounts of iron or pyrite. On this basis, Rosebud coal had 47% of its mineral matter in groups likely to cause slagging compared with 12% for Comanche coal, in agreement with the slagging record. It is concluded that although the particle-by-particle analysis technique used here is in a crude state of development, it can give a correct indication of the possible slagging behaviour of a pulverized coal in cases where conventional slagging indices based on the analysis of the total mean coal ash fail to give the correct indication. 相似文献
979.
Fariborz Goodarzi 《Fuel》1984,63(6):827-833
A study is made of the morphological and optical properties of a blend of concentrated sporinite and vitrinite macerals (equal parts) from the same coal carbonized between 400–900 °C at 5 °C/min under nitrogen. Two coals of different rank were used and the results compared with properties of unblended carbonized sporinites. Coke from a blend of low-rank vitrinite and sporinite produced a two-phase optical texture, whereas coke from the medium-rank vitrinite and sporinite mixture produced a three-phase optical texture. A ‘Transitional Zone’ of optical texture was observed at interfaces between carbonized vitrinite and sporinite, this zone being wider for the coal of higher rank. The increase of bireflectance in oil with carbonization temperature of the sporinite in the blends was lower than for the carbonized unblended sporinite, caused by a reduction in fluidity of sporinite with blending. The decrease of refractive index for sporinite carbonized > 600 °C in the blends was lower than that of the unblended sporinite. 相似文献
980.
Keith D. Bartle Michael J. Mulligan Norman Taylor Terence G. Martin Colin E. Snape 《Fuel》1984,63(11):1556-1560
A number of procedures have been investigated for the calibration of a size-exclusion chromatography (s.e.c.) column in the determination of molecular mass (MM) distributions of coal derivatives. The behaviour of narrow fractions of coal extracts in the MM range 200–3000 was compared with a variety of the more generally available calibration standards. Calibration with preparative s.e.c. subfractions of materials similar to those under study has been recommended. Polystyrene standards are satisfactory, however, for MM < 1000, but above this range other polymer standards should be sought. Universal and molar volume calibration do not apply to coal-derived materials. 相似文献