Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area

Based on data from through-hole and logging,we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors.The results show that the damaged positions of drainage wells are mainly located at the thick clay layer in the low alluvium and the lithological interface in the upper section of bedrock in west mining area.The failure depth of casing is 244-670 m and concentrates at about 270-460 m deep.These damaged positions are mainly located in the bending zone according to three zones of rock layers in the vertical section above the roof divided. Generally,the casing begins to deform or damage before the face line about 30-150 m.Special formation structure and rock mass properties are the direct causes of the casing failure,high mining height and fast advancing speed are fundamental reasons for rock mass damage.However,the borehole configuration and spacing to the casing failure are not very clear.

Controlling Effects of Surrounding Rock to Coal Seam Gas Occurrence

Surrounding rock of coal seam was one of the important factors to gas occurrence. The coal seam gas occurrence was studied by the index of roof strata thickness or sand content rate;we found that there were certain shortcomings. In order to reasonably evaluate the influence of coal seam surrounding rock on gas occurrence in Panji mining area, we quantitatively evaluated the effect of coal seam surrounding rock on gas occurrence by influence coefficient of roof strata thickness, and built six mathematical models of the variational gas content in the mining area which is divided into six gas geological units. The results shows that the coal seam gas content is mainly influenced by 20 mroof strata in each gas geological unit, the gas content presents the tendency of increase, and with the influence coefficient of strata thickness increases, they exist a significant linear relationship.

Experimental research into the effect of gas pressure,particle size and nozzle area on initial gas-release energy during gas desorption

Coal and gas outburst is a violent disaster driven by released energy from gas desorption.The initial expansion energy of released gas(IEERG)is a new method to predict coal and gas outburst.In this paper,an instrument for IEERG measurement was developed.Compared with previous setups,the new one which is equipped with three convergent nozzles and quick-release mechanism gets improved in data acquisition and gas sealing and releasing performance.To comprehensively know the effect of gas pressure,particle size,and nozzle area on IEERG,a series of experiments were carried out with this new setup.The variable control test results indicated that the gas pressure-IEERG curves remain the linear trend and the particle size-IEERG curves maintain the negative exponential trend for nozzle areas at 1.13,2.26,and3.39 mm2,respectively.The increase in nozzle area leads to deceases in value of IEERG and absolute value of slope of fitting curves in each test.In addition,the orthogonal experiment showed that the influence of gas pressure,nozzle area,and particle size on IEERG decreases in turn.Only gas pressure had a marked impact on IEERG.This work offers great importance in improving the accuracy of prediction of coal and gas outburst.

A New Discovery on the Deformation Behavior of Shale Gas Reservoirs Affecting Pore Morphology in the Juhugeng Coal Mining Area of Qinghai Province, Northwest China

Objective The Juhugeng mining area in Qinghai Province of northwest China has attracted wide attention among geologists for it hosts typical coal measure gases.The shale gas reservoirs were reformed by intensive structural movements during geological periods,

Experiment study on the propagation laws of gas and coal dust explosion in coal mine

The experiment of gas and coal dust explosion propagation in a single lanewaywas carried out in a large experimental roadway that is nearly the same with actual environmentand geometry conditions.In the experiment,the time when the gas and coal dustexplosion flame reaches test points has a logarithmic function relation with the test pointdistances.The explosion flame propagation velocity rises rapidly in the foreside of the coaldust segment and comes down after that.The length of the flame area is about 2 timesthat of the original coal dust accumulation area.Shock wave pressure comes down to therock bottom in the coal dust segment,then reaches the maximum peak rapidly and comesdown.The theoretical basis of the research and assemble of across or explosion is suppliedby the experiment conclusion.Compared with gas explosion,the force and destructiondegree of gas and coal dust explosion is much larger.

Safety appraisement on building natural gas pipeline over coal mining subsidence area

The target of the text is to scientifically appraise dynamic development of surface deformation in subsidence area and its influence on groundwork stability of natural pipe and then adopt some technological measures to ensure safe circulation of natural pipeline. Analysed the influence on natural pipeline from coal mining subsidence in the way of pipeline grade variation, vertical curve variation, transverse deformation, horizontal pull and compression deformation and pipe stress variation etc., and described detailed surface subsidence product and its used time among initial phase, active phase and decline phase in the course of surface movement deformation time. In the context of considering surface subsidence that doesn＇t reach basic latter end and residual subsidence quantity, the text confirmed the calculation method of residual deformation in surface subsidence area, and gave the technological measures about building natural gas pipeline in subsidence area finally.

Influence of temperature and Ca(OH)2 on releasing tar and coal gas during lignite coal pyrolysis and char gasification

The yield of tar and syngas has been investigated by catalytic pyrolysis of Pingzhuang lignite(PZL)over Ca(OH)2 catalyst in temperature range of 600℃-1000℃in a tube furnace.The results show that the yield of volatile pyrolysis increases and char decreases with rising temperature for both raw and catalyzed Pingzhuang lignite.The hydrogen fraction(H2)increased from 20%to 40%for the PZL sample;but,for the PZL-Ca(OH)2 sample,H2 fraction fluctuated randomly between 35%to 42%,with the maximum H2 fraction found at 1000℃.The Gaschromatography mass-spectroscopic(GC-MS)analysis revealed that the maximum tar yield at 800℃and 700℃was obtained for PZL and PZL-Ca(OH)2,respectively.The surface morphology of PZL and PZL-Ca(OH)2 chars underwent different transformation in the presence of catalyst as illustrated by SEM/EDX,FTIR,and BET analysis.Furthermore,char sample was investigated for the carbon conversion and reactivity index using TGA analysis under N2 and CO atmosphere.

Features of gas geology and its main controlling factors in Pingxiang Mining Area, Jiangxi Province

Pingxiang Mining Area in Jiangxi Province is one of the major coal-producing areas and is prone to serious coal and gas outburst, therefore, it is of significance to research on gas geological features and its controlling factors. Based on the analysis of gas data collected from geological exploration and coal mining, the research reveals that the features of gas geology vary significantly between west part and east part of Pingxiang Mining Area, and it is characterized by high gas mines with se- rious coal and gas outburst in the west part and low gas mines with no coal and gas outburst in the east part. The main controlling factors to gas geology are discussed, and the great difference of gas geology between west part and east part is the result of comprehensive effect by geological factors. Concerning the gas generation, the coal rank in the west part is higher than that in the east part, which is favorable to generate more gas in the west part than in the east part. Concerning the gas preservation, the structures are characterized by gliding nappe in the west part and by tectonic window in the east part, the surrounding rocks are characterized by poor permeability in the west part and comparatively good permeability in the east part, and the characteristics of coal rank and coal body structure are favorable to gas preservation in the west part and favorable to gas emission in the east part.

Micro shape of coal particle and crushing energy

A large amount of energy is consumed in a coal and gas outburst since a mass of coal is pulverized and ejected, accompanying a great quantity of gas emitted, resulting in a major mining hazard in underground coal mining around the world. Understanding how potential energy stored in gassy coal seams dissipates in the process of outbursting may possibly be a key to clarify the mechanisms responsible for coal and gas outburst. The present study was aimed to evaluate energy for crushing coal to various size fractions in coal and gas outbursts through theoretical and experimental investigation into the shape of fine coal particles and their equivalent diameter. Theoretical analysis indicates that the shape of a particle has a significant impact both on its equivalent diameter and hence on its outer surface area.Microscopic observations demonstrate the particle fraction with diameters less than 0.075 mm, produced from crushing coal samples, mostly takes on a spherical or ellipsoidal shape, and experimental data also show this part of particles consists of 30%–50% surface area newly generated from crushing operation,though these fine coal accounts for only less than ten percentages by weight. Further, analysis of experimental data indicates that the total surface area of this particle size fraction varies exponentially with input crushing energy, and the specific area energy is not a constant but probably in association with physical properties and textures of material.

我国北方农村生活燃煤情况调查、排放估算及政策启示

北方重灰霾频发时段与集中燃煤在冬季高度重合,引发了对农村散煤严重污染的担忧,但缺乏有力的统计数据支持.2014年9月,在河北保定开展了当地农村生活能源使用情况入村调查,共获得5个村庄中543户家庭的能源使用数据.结果表明:1保定农村地区散煤、电、液化气的使用覆盖率均很高,分别达到97%、100%和94%,反映了当前农村居民的能源消费更倾向于商业购置;而木柴和秸杆的使用覆盖率则较低,分别为13%和11%,表明传统的依赖于木柴和秸杆的能源方式已发生了根本改变.2目前煤炭在农村能源结构中仍居主导地位,占近80%(其中散煤占76%,蜂窝煤占2%),其次为电力(10%)、液化气(5%),秸杆和木柴的比例(小于5%)均较低.3调查估算,保定农村地区在2013年冬季采暖季(2013年11月─2014年3月)散煤用量超过500×104t,高于《中国能源统计年鉴(2013)》中河北全省2012年农村散煤的用量(467×104t),表明现有能源统计体系有待进一步完善.4保定农村地区散煤的烟粉尘(即PM)和SO2排放量分别为5.4×104和11.2×104t,均超过了《中国环境统计年报(2013)》中保定的工业废气和城镇生活领域相应的排放量(甚至超过2个领域排放量之和),表明农村散煤燃烧的排放问题确应引起特别关注.由于农村散煤燃烧排放高度较低,其单位排放对空气污染的贡献要远高于高架源排放,因此,建议国家和地方将农村能源结构调整置于当前能源结构调整计划的最优先领域,采取综合措施,消除农村散煤使用的污染排放,这可能是应对当前冬季灰霾问题的关键举措之一.

劳动力转移对农户煤炭消费量的影响研究——陕西农村的实证调查

中国农村经济快速发展,劳动力转移人数增多带来农民收入增加,煤炭等能源消费量也在不断发生变化。利用陕西省农村地区"劳动力转移与农村生活能源调查"数据,运用Tobit回归模型研究劳动力转移在农户煤炭消费量的影响。研究发现劳动力转移人数的增加显著地降低了农户煤炭消费量;劳动力转移收入的增加显著地提升了农户煤炭消费量;劳动力转移收入占家庭总收入的比重越高则农户煤炭消费量越低;最后为提高农民收入和煤炭的使用效率以及新农村建设发展提出建议。

山西贫困地区城乡发展不平衡成因分析

近年来,山西贫困地区城乡发展不平衡问题日益突出,重点对其成因进行了分析,发现除历史形成的城乡二元结构等共性因素外,贫困地区自身还存在特殊原因:过度依赖煤炭资源的粗放型经济增长方式、城镇化严重滞后于工业化和经济发展水平、县域经济发展缓慢、自然地理条件恶劣。只有针对性地采取措施,才能加快贫困地区城乡一体化进程。

我国农村能源发展状况与未来展望

能源和电力是美丽乡村建设的组成部分。本文回顾了农村地区的能源发展成果;界定了农村地区的能源供求体系;重点分析了农村地区的能源消费结构和可再生能源资源开发状况以及农村能源发展面临的主要问题;指出在我国农村地区存在着能源和电力发展的不平衡和不充分的突出矛盾。

政策驱动下的中国北方农村地区清洁取暖方式

北方农村地区冬季清洁取暖是我国能源消费革命、农村生活方式革命的重要内容,也是重大民生工程和暖心工程,如何兼顾其经济性、适用性和环保要求备受关注。为此,以农村清洁取暖重点地区--京津冀及周边"2+26"城市为研究对象,在现场调研、入户实测的基础上,从技术、经济和环保3个维度,对该区4种主要的清洁取暖方式(燃气壁挂炉、蓄热式电暖器、空气源热泵和清洁煤炭取暖)进行对比分析,并提出了针对性的建议。研究结果表明:①燃气壁挂炉替代燃煤取暖是较为经济的选择,但应严把产品能效和排放准入关,建议城镇和经济较发达的农村地区燃气采暖普及推广节能环保的冷凝式壁挂炉;②农村既有建筑普遍缺乏保温措施、采暖能耗高,应重视保温隔热措施,建议推进清洁采暖过程中同步实施房屋节能改造并给予适当补贴,结合农村新型城镇化建设推进集中供暖;③洁净煤取暖在部分农村地区较长时间内仍将存在,但须严格煤质监管,建议采取"洁净型煤+专用炉具+一氧化碳监测"整套措施;④坚持因地制宜方略,各地应立足资源禀赋,选择合适的取暖路径和取暖设备,可再生能源丰富、电网配套条件好的地区,宜重点推广蓄热式电暖器或空气源热泵取暖;⑤关注农村"后煤改气、煤改电"时代的平稳运行问题,建议从国家层面统筹研究制定补贴退出方式及退出后的贫困户精准补贴问题,注重环保政策和绿色发展理念的宣传贯彻,真正做到"改得起、用得起、愿意用"。

成型生物质燃料在北京农村替代生活用煤研究

能源危机使得寻找新型清洁能源成为必然,成型生物质燃料以其优良的清洁特性及燃值成为替代煤碳的备选产品。北京地区农村居民对于煤碳有着极大的依赖性,因而成型生物质燃料在农村具有最可能的替代性和市场空间。从北京农村用能结构入手分析成型生物质燃料在该地区的应用前景,从调研数据中找出了农户选用能源的关心要素,结合政府政策扶持分析替代的可行性,并应用计算机软件建立模型对未来5年的成型生物质燃料需求情况进行了预测。

以煤代赈与西部贫困地区农村生态建设的保障机制探讨

本文探讨了农村能源结构与生态环境的相关性;指出了我国农村能源结构与西部发达国家的差距;针对我国西部生态环境建设重点地区的农村能源问题,分析了以煤代赈的可行性,提出了以煤代赈的新的国家西部扶持政策的措施建议。

农村天然气使用安全影响因素分析及对策研究

通过已查隐患统计分析,给出了已有"煤改气"工程隐患排查重点,以及拟有"煤改气"工程防范重点,确定了影响农村天然气使用安全的主要因素,在此基础上,提出了保证农村天然气使用安全的对策建议。

煤矿区城乡生态化建设与经济发展模式的选择

煤矿区作为城乡经济发展集聚区,构建煤矿区城乡生态化建设中的经济发展模式是实现煤矿区经济可持续发展的必然选择。根据城乡生态化建设的内容,构建煤矿区城乡生态化建设内容;依据煤炭资源开发中经济变量,遵循可持续发展、生态产业及城市和农村生态系统复合生态系统发展规律,提出煤矿区城乡生态化建设中的经济发展模式。在人民生活质量持续提高、经济持续发展的同时,寻求山西省煤矿区资源的持续利用、生态环境的稳定协调。为优化资源环境经济体系提供理论和实践支持;对保障煤矿区经济的可持续发展具有现实的指导意义。

采煤沉陷区土地流转中农民福利变化分析——以淮南市为例

本文基于国外福利改进的判断标准和福利衡量方法,通过对淮南市采煤沉陷区的实地调查和访谈,对资源型城市采煤沉陷区农民因农地流转发生其福利的变化,以及土地流转过程中影响农民福利发生变化的因素及福利变化状况进行分析。得到,沉陷区土地流转为生态园的模式能提高农民的福利水平。这为政府更好地治理采煤沉陷区和制定合理的沉陷区土地流转政策提供决策依据;也为深入研究资源型城市政府土地流转补偿政策和社会保障制度的制定提供参考,为全国采煤沉陷区土地治理的改革提供科学的设计方案。

集体产权、资源禀赋与农村政治生态优化研究

集体产权作为乡村政治活动的核心,其所有权和成员权的关系不仅影响农村经济发展,更影响村庄的政治生态。新中国成立70年来,煤矿产权历经多次改革,对于资源型农村来说,煤矿集体产权的变化深刻影响着农村的政治生态,尤其是煤矿资源型农村由于其资源禀赋的不同,加之集体产权变化的背景下,资源型农村的政治生态具有极其不同的表现形式和特殊性,突出表现为在煤矿资源较为丰富的农村,各种利益主体围绕煤矿资源的产权及其衍生财富与村庄公共权力行使之间激烈的竞争和争夺。因此,必须从厘清产权关系、坚持集体产权所有权和成员权的统一、健全和完善村民自治民主制度等方面,探索资源型农村政治生态的优化路径。