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41.
实验测定了林西矿肥煤样品30~900℃煤自燃全过程热动力学特征参数,得出:TG/DTG曲线显示煤样DTG初始临界温度45℃,干裂温度122℃,活性温度195℃,增速温度265℃,质量极大值温度342℃,着火温度465℃,最大热失重速率温度515℃和燃尽温度690℃;DSC曲线显示,煤样初始放热温度60℃、最大热释放速率温度511℃。结合TG-DTG-DSC曲线综合分析可知,煤温达到510℃左右时煤样反应最剧烈。由煤自燃标志气体测定实验系统得出:煤温130℃后CO,CO 2释放量迅速增加,210℃增加速度下降;CH 4,C 2 H 6含量变化具有规律性且两者变化相近;C 2 H 4出现温度为130℃;C 2 H 4/C 2 H 6比值在190~350℃有较强的规律性,呈上升趋势且上升速度较快;350℃之后,CH 4,C 2 H 6,C 2 H 4体积分数均开始急剧增大;C 2 H 4/CO与C 2 H 4/CO 2变化趋势大致相同,在130~350℃时缓慢增长,达到350℃后比值呈指数形式上升。经拟合曲线,得到活化能的3个突变点温度:70,180,220℃,其中180℃与交叉点温度相吻合。通过以上研究,得到了肥煤自燃全过程的热力学特征参数,为实际生产中防治煤自燃提供了理论依据。 相似文献
42.
China is the world's largest energy consumer, and coal accounts for a higher proportion of the country's total energy consumption, yet during its 12th five-year plan (2011–2015), the coal share among total energy consumption significantly decreased. Previous studies exploring energy performance typically used energy consumption as an input, but this lacks the analytical capacity for the structure of energy consumption. Thus, this study splits energy input into two different inputs, coal consumption and non-coal energy consumption, and based on their differences with other variables, uses the hybrid dynamic data envelopment analysis model to assess the energy performance of China's provincial industrial sector during the period 2011 to 2015. We then compare coal consumption's and non-coal consumption's rooms for improvement and conclude that provinces in eastern and central China should reduce the amount of coal consumption, thereby improving energy performance. Conversely, provinces in the western region should target a balance between energy utilization efficiency and coal consumption. 相似文献
43.
为提高长大隧道施工及运营通风过程中竖井通风效率,实现隧道节能通风。依托实际隧道工程,基于Fluent软件,选用RNG k-ε湍流模型,对无竖井风塔、圆柱风塔、矩形风塔和凸台状风塔4种结构、不同环境风速工况下的流场进行数值模拟,并对模拟结果进行交叉比对分析,提出最优化的竖井风塔结构形式。研究结果表明:采用风塔结构竖井出流量要远大于无风塔结构竖井出流量;对于不同竖井风塔外型结构,竖井出流量与环境风速关系呈多项式函数;当倾斜角为45°、圆心角为90°时,凸台结构对应竖井出流量最大,且受环境风影响波动较小,通风稳定性较好。建议竖井出口结构选用矩形或凸台状,实现对环境风的高效利用,提高竖井通风效率。 相似文献
44.
为响应国家节能减排和循环经济的理念,本文提出一种新的园区污水处理方式-以污治污:利用企业A废水中的碱性物质与消耗企业B废水中的氢离子,再向废水中投加石灰石去除多余的氢离子,投加液碱去除废水中的铜离子和锌离子。优化后的废水处理方式可减少盐酸、石灰石的使用量,从源头上减少了资源的浪费和排入外环境的污染物,对社会发展和生态环境均具有明显的正效益。 相似文献
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46.
ABSTRACT Refrigerant pressure drop and temperature change in pipes are normally ignored in the thermodynamic analysis of traditional vehicle air conditioning system, this will result in serious errors. In this Paper, pressure drop and temperature difference are simulated in different pipes of electric vehicle (EV) heat pump system to analysis the effects of pipes in the actual EV heat pump system. The results indicate that the greater the mass flow, the faster pressure drop increases, the temperature difference decreases. Pressure drop of saturated liquid refrigerant is smaller than that of saturated gas refrigerant at the same saturation pressure and mass flow rate. The higher the refrigerant pressure (no phase change), the slower pressure drop decreases, the faster the temperature difference decreases. Pressure drop decreases with the increment of bending angle of the pipe. For EV heat pump system, suitable valves and less branches are helpful for energy saving of the system. Shortening the pipe between compressor and condenser can reduce temperature change obviously. Pressure drop per unit length in the pipe between evaporator and compressor is large especially in heating mode because of lower refrigerant density. It even reaches to over 100 times of that in the pipe between condenser and throttle valve in heating mode and has negative effects on the performance of the system. If the evaporator is closer to the compressor and the number of branches is less, then pressure drop will decrease a lot, which will be advantageous for energy saving of the heat pump system. 相似文献
47.
Krzysztof Baszczyński 《International journal of occupational safety and ergonomics》2018,24(2):171-180
Industrial workplaces pose concurrent hazards to the upper part of the head and the eyes. Under the circumstances, workers may use protective helmets in conjunction with protective goggles or spectacles. In order to assess the compatibility of this equipment, a method and a test stand for evaluating the behavior of safety helmets and protective goggles/spectacles upon the impact of a falling weight were designed. The results of tests concerning the displacement and deformation of helmets and spectacles/goggles, the forces acting on the helmets, as well as the forces exerted by the spectacles/goggles on the headform upon falling weight impact are presented. The results revealed the ways in which the tested equipment interacted with each other. The influence of equipment construction on the test results was analyzed and inferences concerning the safety of the studied protective devices were made. Some general construction guidelines were formulated for the compatibility of the equipment. 相似文献
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49.
为探究单轴应力作用下煤氧化和传热特性,利用自制荷载加压煤自燃特性参数测定装置对炉体内长焰煤煤样进行程序升温。结合程序升温过程中煤临界温度Tc和Tg,对其进行阶段划分:阶段1为30℃~Tc;阶段2为Tc~Tg。计算了不同单轴应力下2个阶段煤表观活化能和平均耗氧速率。根据能量守恒得出程序升温过程煤导热系数随温度的变化,进一步分析煤导热系数与单轴应力的关系。结果表明:阶段1单轴应力为4 MPa时为临界轴压,煤表观活化能最大,平均耗氧速率最小;阶段2煤表观活化能和平均耗氧速率随单轴应力增大均呈抛物线变化,单轴应力为2.7 MPa时为临界轴压,煤表观活化能最大,平均耗氧速率最小;阶段1和2煤导热系数随温度升高均先减小后增大,并且煤导热系数随单轴应力增大呈三次函数变化。 相似文献
50.
Research suggests that previous, current, and prospective extractive industry activities influence perceptions of new development. Studies that have drawn this conclusion, however, have usually focused on specific projects in specific communities. Here, these factors are examined on an aggregate, national scale. Combining geospatial data on extractive industry activities and survey data from a nationally representative sample (N = 1061), the influence of extractive industry activities on support for fracking is studied. While limited evidence is found for the impact of proximity to oil and gas wells or production on support for fracking, employment levels in the natural resources and mining sector in the respondent’s county and residence in an area experiencing active oil and gas development significantly increase support for fracking. The results highlight the role of spatial and community factors in shaping support for energy development. 相似文献