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An rescaled range analysis on the characteristics of coal seam development in the Eastern depression
The characteristics of coal seam development, and the prospects of a favorable coal-forming area, were evaluated for the Liaohe Basin located in China. The Number 3 and Number 9 coal seam thickness series from 60 nearly equally spaced bores in the Eastern depression of the Liaohe Basin were examined by a rescaled range analysis. The results indicate that the Hurst exponents of the Number 3 and Number 9 coal seam thickness series are 0.69 and 0.68, respectively. This suggests the presence of persistence. As the bore spacing increases the Hurst exponent of the Number 3 series gradually decreases (H changes from 0.69 to 0.52) and shifts from persistence to randomness. The Hurst exponent of the Number 9 thickness data gradually increases (H changes from 0.68 to 0.91) and always shows the characteristic of persistence. A combination of geological characteristics and the series data allow the conclusion that it is more suitable for the Number 9 coal seam to form in the Northeastern part of the Eastern depression than the Number 3 coal seam....
2020-06-12 16:18:46浏览：1426
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Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress co
Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face....
2020-06-12 16:18:29浏览：1430
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Rate of pozzolanic reaction of two kinds of activated coal gangue
Two kinds of activated ways are used to prepare activated coal gangue fine powder,one is calcining coal gangue at 800 ℃ (gangue A),and the other is calcining coal gangue with a certain calcite at 800 ℃ (gangue B).The experiment shows that strengths of blended cement mortar with coal gangue B are higher than that of blended cement with coal gangue A.Hydration of cements with the two kinds of activated coal gangue is investigated through a differential thermal analysis.The weight loss due to Ca(OH)2 decomposition of hydration products by differential thermal anaiysis/thermo gravimetric (DTA/TG) can be used to quantify the pozzolanic reaction.A new method based on the composition of hydration cement is proposed to determine the degree of pozzolanic reaction.The results obtained suggest that the degree of pozzolanic reaction of gangue B is faster than that of gangue A....
2020-06-12 16:17:53浏览：1407
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Separation of arenols from a high-temperature coal tar
A high-temperature coal tar collected from Xuzhou Coking Plant,Saint-Gobain Pipelines (Xuzhou) Co.,Ltd.was exhaustively extracted with petroleum ether (PE).The extract was sequentially eluted through silica gel with PE and PE/ethyl acetate (EA) mixed solvents (volume ratio 2:1 ) to afford two eluted fractions.The extract and eluted fractions were analyzed with gas chromatography/mass spectrometry.In total,14 arenols were detected,including phenol,cresols,xylenols,fluorenols,phenanthren-3-ol and pyren-1-ol....
2020-06-12 16:17:39浏览：1431
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Microwave-assisted extraction of Shenfu coal and its macromolecule structure
Coals consist of some molecules trapped within an organic matrix from which some organic compounds can be extracted by solvents. The Soxhlet technique has been widely used for extracting organic compounds. Microwave heating methods may be successfully applied in the field of coal science. Acetone extraction yields and the chemical composition of the extract were inves-tigated using a typical Chinese coal, Shenfu coal, with microwave-assisted extraction. The acetone extract and residue were ana-lyzed by GC/MS and carbon-13 nuclear magnetic resonance spectroscopy respectively. The carbon spectra were converted into several numerical parameters, fa, Ha, Xb, which indicate the difference in macromolecular structure between Shenfu coal and its residue. Furthermore, a hybrid genetic algorithm was employed using these parameters to approximate a coal macromolecule by assembling the structural fragments or functional groups into a large and complicated structure....
2020-06-12 16:17:26浏览：1418
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DISASTER ANALYSIS AND COUNTERMEASURES OF LAND SUBSIDENCE CAUSED BY COAL CUTTING IN CHINA
In recent years, many coal-producing countries have paid great attention to the land subsidence causedby coal cutting. In China, because of the dense population in coalfield areas, the land subsidence hazard is more seri-ous. After a brief analysis on the mechanism of land subsidence, this paper gives a comprehensive and systematical ac-count on all kinds of hazards caused by the land subsidence in China. The study shows that land subsidence has endan-gered land, buildings, traffic and communication lines, dykes and dams. It also causes damage to ecological and socialenvironment. In order to lessen the hazard of land subsidence, preventive measures should be taken to reduce the col-lapse amount, such as extraction with stowing, banded mining system, succession and coordination mining system, orhigh-pressure mudflow between rock strata. Measures of reinforcing or moving certain buildings should also be taken toreduce the destructive degree. In order to harness the subsidence land and bring them under control for farming, mea-sures should be taken such as filling with spoil or fine breeze, excavating the deeper and covering the shallower land....
2020-06-12 16:17:04浏览：1438
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Modelling of the relationship between trace elements and three species of sulfur in coal
Based on the determination of several trace elements in coal particulate of different specific gravity, three-variables regression equations relate the contents of trace elements Be, Cd,Co, Pb, Cu, Ni, As and three species of sulfur in coal were well established. For elements Cd, Co, Pb, Cu and Ni, the regression equations were successfully used for prediction of these trace elements in individual part of coal with different specificgravity. Factor analysis was also used to analyze the data sets.The results showed that a three factor model can interpret the datasets reasonably. Trace elements Cd, Co, Pb, Cu, Ni, inorganic sulfide and total sulfur in coal are high correlated with the first factor. Trace elements Be, sulfate and organic sulfide are high correlated with the second factor and trace elements Cr and As are high correlated with the third factor. The factors can be interpreted by the chemical properties of these elements....
2020-06-12 16:16:51浏览：1425
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Analysis and Research of Factors Affecting Coal Mining with Plough
Coal mining with ploughs is an ideal coal mining technology for thin a nd thinner coal seams. The existence conditions of coal seams are different for each other, which affects coal mining with ploughs to different degrees, and the application results are also different. The authors analyze the affecting factors by means of mathematical methods. The research is useful to the wide appli cation of ploughs....
2020-06-12 16:16:29浏览：1421
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Isothermal reduction of titanomagnetite concentrates containing coal
The isothermal reduction of the Panzhihua titanomagnetite concentrates (PTC) briquette containing coal under argon atmosphere was investigated by thermogravimetry in an electric resistance furnace within the temperature range of 1250-1350°C. The samples reduced in argon at 1350°C for different time were examined by X-ray diffraction (XRD) analysis. Model-fitting and model-free methods were used to evaluate the apparent activation energy of the reduction reaction. It is found that the reduction rate is very fast at the early stage, and then, at a later stage, the reduction rate becomes slow and decreases gradually to the end of the reduction. It is also observed that the reduction of PTC by coal depends greatly on the temperature. At high temperatures, the reduction degree reaches high values faster and the final value achieved is higher than at low temperatures. The final phase composition of the reduced PTC-coal briquette consists in iron and fer-rous-pseudobrookite (FeTi2O5), while Fe2.75Ti0.25O4, Fe2.5Ti0.5O4, Fe2.25Ti0.75O4, ilmenite (FeTiO3) and wustite (FeO) are intermediate products. The reaction rate is controlled by the phase boundary reaction for reduction degree less than 0.2 with an apparent activation energy of about 68 kJ·mol-1 and by three-dimensional diffusion for reduction degree greater than 0.75 with an apparent activation energy of about 134 kJ·mol-1. For the reduction degree in the range of 0.2-0.75, the reaction rate is under mixed control, and the activation energy increases with the increase of the reduction degree....
2020-06-12 16:16:24浏览：1399
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洛阳分公司循环水用量优化
在分析洛阳分公司循环水使用情况的基础上，参比2012年工业水平衡测试数据，对分公司范围内所有装置的循环水用户进行摸底调研，查找各装置在循环水使用中存在的问题，提出相应的优化措施。通过逐步实施后，2013年洛阳分公司在增开两套装置的情况下，循环水消耗量较2012年减少1787.2万吨，节约循环水费用357.4万元，取得了较为明显的经济效益。...
2020-06-12 15:55:33浏览：1413
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甲醇气体标准样品的研制
介绍了甲醇气体标准样品的制备和定值方法，考察采用重量法制备氮气中甲醇标准气体样品的重现性、标准气体的均匀性和稳定性。试验表明，甲醇气体标准样品在气瓶内均匀性良好，在12个月研制期间没有不稳定趋势。摩尔分数为149．2×10-6甲醇气体标准样品，扩展不确定度为3％，能够满足环境污染源废气中甲醇气体监测的要求。...
2020-06-12 15:51:20浏览：1410
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生物质与煤混烧燃烧特性研究
利用TG-DTG热分析技术对煤、生物质及二者混合物的燃烧过程进行分析,研究了煤种、生物质、生物质添加比例、升温速率及氧气流量等因素对燃烧特性的影响.结果表明,生物质的着火特性、燃尽特性和燃烧性能明显优于原煤;添加生物质可以改善原煤的燃烧特性,随着生物质添加量的增加,燃烧性能改善越显著;升温速率增加,着火特性指数和综合燃烧特性指数升高,燃尽性能降低;增加氧气流量,可以显著改善燃料的燃烧性能....
2020-06-12 15:44:14浏览：1419
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生物质与煤的混合燃烧实验研究
为了解生物质和煤的混燃特性,利用热天平对生物质、煤及其混合试样进行了热重实验研究.考察各种试样的着火温度、燃烧速率最大时温度、燃尽温度和最大燃烧速率等燃烧特征参数,并对实验数据进行了分析处理.求出了反应的动力学参数活化能E和频率因子A.结果表明,同烟煤比较,生物质有较低的燃烧特征温度和较快的燃烧速率.在烟煤中加入生物质共燃后,着火燃烧提前,同时可以获得更好的燃尽特性....
2020-06-12 15:43:43浏览：1404
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燃料乙醇系统模拟平台开发及应用
对典型燃料乙醇系统进行了分析,阐述了目前该系统相关全流程模拟模型的不足以及由非线性和复杂性等特征导致的系统建模难点.在此基础上,运用VC撑编程工具和SQLSERVE开发了全新的燃料乙醇系统模拟平台,该平台可模拟燃料乙醇实际生产过程,能够从物质流,能量流、水流、价值流等方面对系统开展工业生态学分析.最后利用实际生产过程中出现的两个问题案例对平台进行了检验....
2020-06-12 15:40:53浏览：1403
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不同超声提取时间对凝血后乙醇浓度检测的影响
目的 探讨已发生凝血的血液样本采用超声处理的必要性和最佳时间.方法 抽取500名驾驶员血液样本各两份,其中1份为抗凝血,1份为未抗凝血.抗凝血样本采用直接进样,未抗凝血分别采用旋涡震荡后直接进样和进一步以不同时间超声处理后再进样,采用GC法分析各样本中乙醇浓度.以抗凝血检测结果为标准值,进行比较和分析.结果 500份抗凝血液样本中有462份检出乙醇,相应462份未抗凝血液样本中445例检出乙醇.未抗凝血经60min超声处理后再进行GC检测,所得结果与相应抗凝血相符,而采用更长、更短时间的超声处理,或不加超声处理的检测结果绝大多数与相应抗凝血检测值存在显著性差异(P＜0.01).结论 机动车驾驶员血液中乙醇浓度测定应使用抗凝血样本;如样本未加抗凝剂出现凝血后,则应对样本进行超声波处理,时间以60min为宜....
2020-06-12 15:10:47浏览：1425
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