平庄煤田矿区外围及深部含煤性评价及找煤预测

平庄煤田开采元宝山组煤层已有多年,多个矿井面临资源枯竭局面,寻找后备资源已成为目前亟待解决的问题。通过对矿区含煤地层含煤性评价,认为矿区深部的元宝山组不具有形成可采煤层的条件,其下伏的杏园组沉积晚期为扇三角洲相,扇三角洲平原下部朵叶间湾及湖滨地段为聚煤作用有利场所。根据钻探资料证实,在五家矿区、古山矿区和四龙头矿区杏园组上段均见可采煤层,该组应作为找煤预测区目的层加以勘查。

菲律宾某660MW锅炉燃用当地褐煤适应性分析

菲律宾某660 MW机组燃用当地褐煤,在锅炉试运行期间发生了严重的结渣问题,影响了机组带负荷能力,也增加了安全隐患。鉴于此,对燃煤取样后首先在实验室进行了煤质、着火、燃尽、结渣等性能的分析。煤质分析结果显示,试验煤样除部分灰成分超出设计煤质参数范围外,其他煤质参数均在设计范围内,煤样具有一定的代表性。燃烧性能试验结果显示,煤样着火和燃尽性能优良。需要注意的是,试验煤灰中碱性氧化物(Fe_(2)O_(3)、CaO、MgO)成分含量较高,煤灰结渣性能严重。煤粉细度R_(90)在20%~40%、运行氧量在2.5%~4.5%变化时,试烧煤样均具有严重结渣倾向。掌握煤质特性后,又对燃用类似煤种的国内锅炉的设计和实际运行情况进行了调研和分析。最后还针对该机组锅炉燃用试验煤进行了炉内燃烧状态的数值模拟计算。结果表明,此类高碱性氧化物煤种具有严重结渣倾向,燃用时会使锅炉存在以下问题:(1)截面热负荷、燃烧器区壁面热负荷和炉膛容积热负荷略微偏大、炉膛容积偏小;(2)燃尽风率和偏置风角度过大;(3)燃烧器区域没有布置吹灰器;(4)屏底烟温及后屏入口烟温偏高等问题。由于试验煤样结渣性能较强,在现有的锅炉设计条件下不能实现长周期的满负荷安全燃用试验煤样。为了提高锅炉对严重结渣煤种的适应性,建议对燃烧器进行改造,同时增加吹灰器布置,并进行燃烧优化调整试验,保证炉内良好的燃烧组织及有效的吹灰。

乌拉盖褐煤半焦燃烧特性试验研究

为了解褐煤半焦的燃烧特性,以乌拉盖褐煤低温热解半焦为研究对象,在西安热工研究院有限公司自燃试验台上,采用电厂用煤煤质指标的评价体系及测试方法对其进行了试验研究。结果表明:乌拉盖褐煤半焦属于低水分、低挥发分以及高热值煤种,其燃烧性能优异,极易着火燃尽,着火稳定性较好,与国内典型烟煤性质接近,燃用时无需过多采用稳燃措施;但由于其灰熔融性较低,并具有严重的结渣倾向,为防止尾部对流受热面出现严重的结渣与积灰,建议炉膛出口烟温不高于1 000℃,且在运行中需加强吹灰,对于新建机组锅炉,应采用低氧燃烧技术以及较为严格的分级配风措施,以实现低NOx排放。

神华动力用煤燃烧特性研究

整理了10年来神华矿区各矿点的煤质常规及非常规试验数据,并根据动力煤特性判别方法,对神华煤进行评价。同时,将前述基础特性与国内主要烟煤进行比较,以便更为确切的了解神华煤特点,为燃用神华煤的电厂及电力设计院等提供参考。

An assessment of coal pillar system stability criteria based on a mechanistic evaluation of the interaction between coal pillars and the overburden

Coal pillar design has historically assigned a factor of safety(Fo S) or stability factor(SF) according to their estimated strength and the assumed overburden load acting on them. Acceptable Fo S values have been assigned based on past mining experience or a statistical link between Fo S and probability of failure(Po F). Pillar width-to-height(w/h) ratio has long been established as having a material influence on both pillar strength and its potential failure mode. However, there has been significant disagreement on using both factor of safety(Fo S) and w/h as part of pillar system stability criterion, as compared to using Fo S in isolation. This paper will argue that there are valid technical reasons to bring w/h ratio into system stability criteria(other than its influence on pillar strength), as it is related to the post-failure stiffness of the pillar, as measured in situ, and its interaction with overburden stiffness. When overburden stiffness is also brought into pillar system stability considerations, two issues emerge. The first is the width-todepth(W/D) ratio of the panel and whether it is sub-critical or super-critical from a surface subsidence perspective. The second relates to a re-evaluation of pillar Fo S based on whether the pillar is in an elastic or non-elastic(i.e., post-yield) state in its as-designed condition, as this is relevant to maintaining overburden stiffness at the highest possible level. The significance of the model is the potential to maximise both reserve recovery and mining efficiencies without any discernible increase in geotechnical risk, particularly in thick seams and higher depth of cover mining situations. At a time when mining economics are, at best, marginal, removing potentially unnecessary design conservatism is of interest to all mine operators and is an important topic for discussion amongst the geotechnical community.

Performance evaluation methods and instrumentation for mine ventilation fans

Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,we instituted a research project on the measurement methods of key performance parameters such as wind pressure,amount of ventilation and power. At the end a virtual instrument for mine ventilation fans performance evaluation was developed using a USB interface. The practical performance and analytical results of our experiments show that it is feasible,reliable and effective to use the proposed instrumentation for mine ventilation performance evaluation.

Performance assessment of water mist applied in gas burning suppression in underground coal mine

The main objective of the present study was introduced water mist suppressiontechnology to prevent and control gas burning which occurred during drilling at Wu20160working-face in No.10 coal mine of Pingdingshan Ltd..Based on the self-developed ex-periment platform,a series of fire suppression tests to evaluate the performance of a watermist system were conducted.The detailed measurements of the spray characteristics,i.e.,the Sauter Mean Diameter(SMD),the velocity and spray angle which are the main pa-rameters considered in the Study,were obtained by using LS-2000 Sizer.The amount ofwater consumed and the water flux density distribution over the cross section downstreamthe nozzle exit were measured by cup collector method.The operating pressure of thewater mist nozzle is set to 0.5 MPa,the droplet SMD of 104 pm,the water flux density dis-tribution from 0.71 to 8.47 L/(m^2.min),the average velocity of 2.14 m/s.The experimentalresults show that the averaged time required for extinguishment is 3.14 s,and the corre-sponding amount of water used during fire test is about 0.11 kg.The gas fire suppressionsystem reduces the temperature in combustion chamber of the experimental apparatusbelow the ignition point of the gas,which can effectively avoid the occurrence of the gasfire in coal mine.

Evaluating the risk of coal bursts in underground coal mines

Coal bursts involve the sudden,violent ejection of coal or rock into the mine workings. They are almost always accompanied by a loud noise,like an explosion,and ground vibration. Bursts are a particular hazard for miners because they typically occur without warning. Despite decades of research,the sources and mechanics of these events are not well understood,and therefore they are difficult to predict and control. Experience has shown,however,that certain geologic and mining factors are associated with an increased likelihood of a coal burst. A coal burst risk assessment consists of evaluating the degree to which these risk factors are present,and then identifying appropriate control measures to mitigate the hazard. This paper summarizes the U.S. and international experience with coal bursts,and describes the known risk factors in detail. It includes a framework that can be used to guide the risk assessment process.

Evaluation of Security of Mine Ventilation Systems

A mine ventilation system has a deterministic function for the safety of coal production and for the control of mine accidents. So, it has an important meaning to evaluate the security of a mine ventilation system. This paper studied the evaluation index system of the security of a mine ventilation system, and the security of a mine ventilation system was described quantitatively in the safety degree. Finally, an example of the security evaluation was given.

Evaluation of Mayer curve validity on feed blending at the Zarand coal washery plant

The coal processing methods used at the Zarand coal washery plant are the heavy medium bath,jigs,and flotation.The coal-containing materials that are fed to the plant are acquired from different mines,and they have different washability properties.In this paper,the validity of Mayer curve (M-curve),the conventional method for determining coal washability,was evaluated on blending of raw coals that are fed to the plant.Washability curves were prepared for the hand-blended samples and compared with the washability predicted by the Mayer curves.Different samples from different seams and mines were blended by hand in 50:50 ratios,and sink and float tests were performed;the resulting washability curves were in good agreement with the washability curves predicted using the Mayer method for the same blending ratio.This work resulted in the preparation of the optimum plant feed that can be achieved from the blending of different coal samples to produce the best plant yield at a given ash content.

Comprehensive evaluation of water-inrush risk from coal floors

Lower groups of coal seams are presently being mined from water-inrush from coal floors in order to have safe production in the Yanzhou coal mining area. We need to evaluate the risk in the lower groups of coal seams in mines. Based on a systematic collection of hydrogeological data and some data from mined working faces in these lower groups, we evaluated the factors affecting water-inrush from coal floors of the area by a method of dimensionless analysis. We obtained the order of the factors affecting water-inrush from coal floors and recalculated data on depths of destroyed floors by multiple linear regression analysis and obtained new empirical formulas. We also analyzed the water-inrush coefficient of mined working faces of the lower groups of coal seams and improved the evaluation standard of the water-inrush coefficient method. Finally, we made a comprehensive evaluation of water-inrush risks from coal floors by using the water-inrush coefficient method and a fuzzy clustering method. The evaluation results provide a solid foundation for preventing and controlling the damage caused by water of an Ordovician limestone aquifer in the lower group of coal seams in the mines of Yanzhou. It provides also important guidelines for lower groups of coal seams in other coal mines.

The evaluation of the growth pattern of coal-production in Jiangsu Province and suggestions for its sound development

Using Cobb-Douglas production function and Solow Residual, this study establishes a discriminant index to measure the intensive index of coal-production at the section-level, so as to analyze the transfer trend of the growth pattern of Jiangsu＇s coal-production since 1990s. The research shows that the transition of coal production in Jiangsu Province has mainly experienced three phases, which are the quick transition phase from extensive growth to intensive growth （from 1990 to 1994）, the fluctuation phase （from 1995 to 1999）, and the transition back phase from intensive growth to extensive growth （from 2000 to 2003）. On the whole, the coal production in Jiangsu Province nowadays is still featured by extensive growth pattern and largely dependent upon capital inputs. Finally, from the aspect of the technology progress, improving the qualities of labor, changing product structures and improving enterprise management, this study puts forward suggestions on how to transfer the growth pattern of Jiangsu＇s coal-production into intensive type.