铁基载氧体煤化学链制氢的强化反应

为促进铁基载氧体的深度还原提高氢气产量,通过优化反应过程形成强化煤化学链制氢(强化煤CLHG)工艺。采用浸渍法制备铁基载氧体;以梅花井烟煤为原料,在固定床上研究煤与铁基载氧体的质量比对强化煤CLHG的影响;对比了三反应器煤CLHG和强化煤CLHG的制氢过程,对不同阶段的铁基载氧体进行XRD表征;对比二反应器、三反应器以及强化煤CLHG在6次循环实验中的碳转化率和氢气产量。结果表明:当煤与载氧体质量比为1:15时,氢气产量最高达1.74 L/g;强化煤CLHG中的铁基载氧体更多地被还原为FeO或Fe,还原程度加深,同时还原阶段的残炭在蒸汽氧化阶段进一步反应,使得氢气产量比三反应器煤CLHG的高18.4%;在6次循环实验中,强化煤CLHG的碳转化率与三反应器煤CLHG的相差不大,远高于二反应器煤CLHG的;强化煤CLHG的氢气产量始终高于二反应器煤CLHG和三反应器煤CLHG的;强化煤CLHG的单次最高氢气产量为1.76 L/g,循环累计氢气产量为9.54 L。强化煤CLHG缩短制氢时间,制氢能力更优异。

充填床液泛规律及氧煤炼铁极限的探讨

描述了充填床内气、液两相逆向流的实验过程，得到模型实验的规律，并以此分析了高炉氧煤强化炼铁的优化条件。当采用固定风量操作时，理论极限为１５％富氧率，喷煤量３２０ｋｇ／ｔ铁；当采用维持炉缸煤气量不变的操作手段时，理论极限为２０％富氧率，喷煤量３７０ｋｇ／ｔ铁。

浅谈高炉长寿炉衬材料的应用

介绍高炉在氧煤强化炼铁条件下，半石墨化自焙碳砖-陶瓷砌体复合炉衬技术、炉衬材料及其在高炉的应用。

The influence of intensity and properties of tectonic stress on the process of coalification

Through the research on stress metamorphism character of the II1 coal seam in Ludian gliding structure, the stress effecting factors of metamorphism and hydrocarbon generation process of tectonic coal were studied. It is shown that different tectonic stress has different coal evolution effects. Compared with tensional stress, compressive stress, which has apparent anisotropic characteristics, has greater stimulative effect against the increase of coal metamorphic degree, the abscission of functional group and side chains of basic structural unit, and the formation of gas primarily composed of methane.

Process intensification of fine coal separation using two-stage flotation column

Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm×1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage(speed flotation stage) to recover easy-to-float materials quickly, and high energy input in the second stage(recovery stage) to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation.

The shortest period of coal spontaneous combustion on the basis of oxidative heat release intensity

It’s necessary to forecast the shortest spontaneous combustion period for preventing and controlling the coal spontaneous combustion.During the experimental process,a calculating model of the SSCP is established on the basis of the oxidative heat release intensity and thermal capacity at different temperatures.According to the basic parameters of spontaneous combustion,heat of water evaporation and gas desorption,the SSCPs of different coals are further predicted.Finally,this study analyzed the relationships of the SSCP and the judging indexes of the self-ignite tendency.The result shows that the SSCP non-linearly increases with the decrease of dynamic oxygen adsorption and increase of activation energy.Compared with the practical fire situation of mine,this reliable method can meet the actual requirement of mine production.

Effect of a starch-based filter aid on the dewatering of fine clean coal

The dewatering of fine, flotation cleaned coals from Huaibei and Xuzhou (bituminous) and Yongcheng (anthracite) were studied. The supernatant and filter cake were examined to determine the rate and extent of flocculation and dewatering. A starch-based filter aid was used to increase flocculation and dewatering rates. The filtration constant, K, and compression index, s, of the Yongcheng slurry were measured under various conditions. A designed experiment was performed to determine optimum conditions for dewatering. The results showed that the filter aid enhanced flocculation and coagulation of the fine cleaned coal slurry, enhanced the structure of the filter cake and promoted dewatering of the cake. Moisture content in the cake was reduced to 17% after vacuum filtration.

Influence of sulfur content in raw materials on oxidized pellets

The influence of sulfur content in raw materials on oxidized pellets was studied. The results show that most sulfur exists in the form of elementary sulfur in pyrite cinder, and over 95% sulfur is removed in producing pyrite cinder oxidized pellets. The compressive strength of fired pellets drops from 3 186 N to 2 405 N when the ratio of pyrite cinder increases from 40% to 70% under the conditions of preheating at 900℃ for 9 min and firing at 1 230 ℃ for 15 min. The porosity and microstructures of fired pellets prove that the higher ratio of pyrite cinder is given, and the more holes and cracks are achieved, leading to the better reducibility index （RI） and reduction swelling index （RSI）, and the lower compressive strength of fired pellets and the worse reduction degradation index （RDI）.

Effects of Nano Silica, Micro Silica, Fly Ash and Bottom Ash on Compressive Strength of Concrete

In this study, SCM （supplementary cementitious materials）, such as nano silica, micro silica, fly ash and bottom ash, have been evaluated for optimal level of replacement as blending material in cement and concrete. The physical and chemical properties of the above materials were first analyzed. This study focused on compressive strength of concrete with different mixes at different ages. In many cases, products made with fly ash, micro silica, nano silica and bottom ash perform better than products made without them. Test results obtained in this study indicate that up to 5% nano silica, 10% micro silica, 20-30% fly ash and 10% bottom ash could be advantageously blended with cement without adversely affecting the strength. However, optimum levels of these materials are 1-3% nano silica, 3-8% micro silica, 10% fly ash and 5% of bottom ash when we consider the strength of concrete. All percentages are defined by weight unless otherwise mentioned.

Effective Utilization of Coal Fly Ash in Building Material Production

This paper is aimed at verifying utilization possibilities of alkaline modified coal fly ash as cement replacement in the concrete. The influence of alkaline activated coal fly ash originating from Slovakian power plant in Novsky （Si/Al = 3,1） as a partial cement replacement in concrete on compressive strength of hardened composites after 28 and 90 days was investigated. Alkaline activation of coal fly ash was realized in an autoclave at 130 ℃ and pressure of 160 kPa during 5 hours and in a reactor under normal conditions （equal temperature during 36 hours） at solid/liquid ratio of 0.5. Coal fly ash/cement mixtures were prepared with 25 % cement replacement by starting and modified coal fly ash and given in forms. Compressive strengths of composites after 28 and 90 days of hardening were compared to referential composite without coal fly ash and evaluated according to the standard of STN EN 450 by the value of relative strength KR （compressive strength of coal fly ash/cement composite to compressive strength of comparative concrete）. The final compressive strengths of hardened composites based on alkaline activated coal fly ash reached values in the range of 6 up to 50 MPa. In the set of experimental composites based on alkaline activated coal fly ashes, the highest value of relative strength after 28- and 90- days of hardening reached composite with cement replacement by coal fly ash zeolitized in autoclave （105% of compressive strength of referential sample）, what is connected with formation of zeolitic phases on surface of coal fly ash particles. The achieved results confirm that alkaline activation of coal fly ash in an autoclave under observed conditions can be successfully used as a partial cement replacement in concrete of C20/25 and C25/30 in accordance with requirements of standards （STN EN 450 and STN EN 206）.

Four Years of Operating Experience with DryFiningTM Fuel Enhancement Process at Coal Creek Generating Station

Lignite and sub-bituminous coals from western U.S. contain high amounts of moisture （sub-bituminous： 15%-30%, lignites： 25%-40%）. German and Australian lignites （brown coals） have even higher moisture content, 50% and 60%, respectively. The high moisture content causes a reduction in plant performance and higher emissions, compared to the bituminous （hard） coals. Despite their high-moisture content, lignite and sub-bituminous coals from the western U.S. and worldwide are attractive due to their abundance, low cost, low NOx and SOx emissions, and high reactivity. A novel low-temperature coal drying process employing a fluidized bed dryer and waste heat was developed in the U.S. by a team led by GRE （Great River Energy）. Demonstration of the technology was conducted with the U.S. Department of Energy and GRE funding at Coal Creek Station Unit 1. Following the successful demonstration, the low-temperature coal drying technology was commercialized by GRE under the trade name DryFiningTM fuel enhancement process and implemented at both units at Coal Creek Station. The coal drying system at Coal Creek has been in a continuous commercial operation since December 2009. By implementing DryFining at Coal Creek, GRE avoided $366 million in capital expenditures, which would otherwise be needed to comply with emission regulations. Four years of operating experience is described in this paper.