中国煤田自燃灾害及其防治对策

概述了煤田自燃的形成及其危害;阐述了中国煤田自燃灾害的严重情况,论述了煤田自燃的监测方法与治理措施。在此基础上,提出了煤田自燃灾害的减灾与防治对策。      

海水中胶体有机碳的测定──高温燃烧法和紫外/过硫酸钾法的比较

利用切向超滤(cross-flow ultrafiltration)技术对海水中胶体有机碳(COC)和真溶解有机碳(UOC)进行了分离,并分别用高温燃烧法和紫外/过硫酸钾法对胶体有机碳和真溶解有机碳进行了测定。测定结果表明,切向超滤能定量分离海水中的胶体有机碳,高温燃烧法和紫外/过硫酸钾法对胶体有机碳和真溶解有机碳的测定结果没有明显的系统误差,表明这两种方法的氧化效率基本相同,胶体粒子的存在,对紫外/过硫酸钾法的氧化效率没有显着影响。     

桦甸油页岩基础物化特性研究

对油页岩进行了扫描电镜分析,测定了油页岩的密度、可磨性、灰分特性、比热、含油率等物性参数,并采用热重分析仪详细研究了油页岩样品在典型工况下的热解及燃烧特性。结果表明,桦甸油页岩是一种高灰分、高挥发分、低热值和具有中等结渣倾向的劣质燃料;不同矿区的油页岩的品质有区别,其中大城子四层的油页岩品质较好,公郎头十一层较差。利用热解和燃烧的实验数据建立的油页岩热解及燃烧的动力学模型表明,油页岩的热解反应属于一级反应,其燃烧反应在不同的温度范围内可用不同的反应级数来描述。     

综放面巷道煤层自燃预测技术研究

根据综放面巷道自燃环境及条件,提出自然发火预测思路、预测方法,以及煤层自燃特性参数和现场参数的定量测算方法;建立了巷道煤层自燃危险程度和最短发火期的预测模型;最后通过东滩矿4308综放面沿空轨顺的实际模拟及预测,证明其预测精度达90%以上      

煤样自燃性升温程序实验研究

以铜川煤矿煤样为测试样品,利用自主研发的煤层自燃性升温的实验系统,对煤层的自燃过程进行实验模拟。根据实验测试数据对煤温与供气量以及实验过程的指标气体情况进行分析,得出煤层自燃性的临界温度、干裂温度等各个自燃特性。实验结果对煤矿分析和预测煤层自燃的过程具有指导意义。     

煤矸石场自燃治理注浆技术研究与工程实践

煤矸石场在自燃过程中会排放出大量有毒有害气体和烟尘,对周围大气和生态环境产生极大破坏。本文在分析研究区自然地理条件的基础上,通过钻孔注浆法对煤矸石场自燃进行治理,并对钻孔注浆法中的注浆液的材料选择和配制、注浆量和注浆参数的确定、注浆钻孔的钻进工艺、注浆工艺和治理效果检验方法等方面进行了深入研究,通过工程示范验证,取得了较好的自燃治理效果。     

地下煤层自燃区岩石磁性增强特征及机理研究——以内蒙古乌达和宁夏汝萁沟煤矿为例

采用室内加温实验和岩矿测试分析手段,对地下煤层自燃区采集的岩石标本,测定其在不同温度条件下岩石磁性、含铁氧化物含量及其结构的变化情况,分析其特征和变化规律,探讨温度变化引起岩石磁性变化的机理.实验研究表明,温度变化可引起岩石磁性变化,通常在加温过程中多数岩石样品在低于400℃时其磁性较弱且没有明显的变化,继续升温达到含铁氧化物居里点温度前磁性增加,高于居里点温度后磁性消失;再由居里点温度或以上降温过程中磁性显著增强,并在常温下获得较岩石加温前更强磁性,但磁性变化较大.磁性变化主要与岩石中的黄铁矿、赤铁矿、菱铁矿、褐铁矿等含铁氧化物含量及其结构变化有关,岩石样品加热至700℃再冷却到常温以后,其铁磁性矿物含量明显增加;矿物结构有所变化,加温前一般为不规则微粒状、短脉状,加温后多为规则微粒状,且颗粒大小比加温前略有减小,一般为10~150 μm,大多属于多畴(MD)结构,部分膺单畴(PSD)结构.磁性增强的主要原因是含有少量含铁矿物的岩石在温度升高时产生了新的铁磁性矿物(如磁铁矿、磁黄铁矿、磁铁矿等).上述研究成果对解释煤层自燃区磁异常的成因具有重要意义.     

综合物探在煤田自燃区勘查中应用效果分析

在陕北神府矿区石窑店井田煤层自燃勘查中,依据勘查区地质特征,采取了"放射状"不规则网状高精度磁测扫面结合二维地震剖面相结合的综合物探方法,其中高精度磁测扫面确定自燃边界,二维地震剖面解释煤自燃层位。通过对两种物探勘查方法取得的资料进行分析、对比和综合研究,确定该井田2-2煤层存在自燃现象,并圈定了自燃边界。经钻孔验证,综合物探解释的边界和埋藏深度精度较高,其中埋深误差小于8.7m。该区的勘探结果表明采用高精度磁测和二维地震勘探相结合的物探方法,能够准确的圈定煤层自燃边界,为煤矿开发和采掘设计提供可靠的地质信息。     

H2O/CO2污染对煤油燃料超声速燃烧影响数值研究

在纯净空气与H₂O/ CO₂污染空气来流对比试验结果基础上,采用数值计算方法和化学动力学方法,研究了H₂O和CO₂污染组分对煤油燃料超声速燃烧的影响,获得了试验手段难以得到的燃烧室流场参数和性能数据。完成了相应的煤油燃料超声速燃烧室二维数值计算,其中匹配了进口总温、总压、马赫数、氧气摩尔分数和工作当量油气比。将数值计算结果与相应试验测量值进行了对比分析,并结合燃烧室流场数据、性能参数分析了H₂O和CO₂污染的动力学影响、以及对燃烧室性能的影响。研究表明:(1)数值计算结果与实验测量值总体上吻合,两种手段均体现了纯净空气来流时不同煤油当量油气比的燃烧室性能,并反映了一致的“污染效应”影响趋势;(2) H₂O污染、H₂O+ CO₂污染的存在降低了煤油燃料超声速燃烧室性能,体现在燃烧诱导压升、燃烧效率、流向冲量增量的下降,而且随着污染组分含量的增加,燃烧室性能下降越加显著。      

A preliminary methods comparison for measurement of dissolved organic nitrogen in seawater

Routine determination of dissolved organic nitrogen (DON) is performed in numerous laboratories around the world using one of three families of methods: UV oxidation (UV), persulfate oxidation (PO), or high temperature combustion (HTC). Essentially all routine methods measure total dissolved nitrogen (TDN) and calculate DON by subtracting the dissolved inorganic nitrogen (DIN). While there is currently no strong suggestion that any of these methods is inadequate, there are continuing suspicions of slight inaccuracy by UV methods.This is a report of a broad community methods comparison where 29 sets (7 UV, 13 PO, and 9 HTC) of TDN analyses were performed on five samples with varying TDN and DIN concentrations. Analyses were done in a “blind” procedure with results sent to the first author. With editing out one set of extreme outliers (representing 5 out of 145 ampoules analyzed), the community comparability for analyzing the TDN samples was in the 8–28% range (coefficient of variation representing one standard deviation for the five individual samples by 28 analyses). When DIN concentrations were subtracted uniformly (single DIN value for each sample), the comparability was obviously worse (19–46% cv). This comparison represents a larger and more diverse set of analyses, but the overall comparability is only marginally better than that of the Seattle workshop of a decade ago. Grouping methods, little difference was seen other than inconclusive evidence that the UV methods gave TDN values for several of the samples higher than HTC methods. Since there was much scatter for each of the groups of methods and for all analyses when grouped, it is thought that more uniformity in procedures is probably needed. An important unplanned observation is that variability in DIN analyses (used in determining the final analyte in most UV and PO methods) is essentially as large as the variability in the TDN analyses.This exercise should not be viewed as a qualification exercise for the analysts, but should instead be considered a broad preliminary test of the comparison of the families of methods being used in various laboratories around the world. Based on many independent analyses here, none of the routinely used methods appears to be grossly inaccurate, thus, most routine TDN analyses being reported in the literature are apparently accurate. However, it is not reassuring that the ability of the international community to determine DON in deep oceanic waters continues to be poor. It is suggested that as an outgrowth of this paper, analysts using UV and PO methods experiment and look more carefully at the completeness of DIN conversion to the final analyte and also at the accuracy of their analysis of the final analyte. HTC methods appear to be relatively easy and convenient and have potential for routine adoption. Several of the authors of this paper are currently working together on an interlaboratory comparison on HTC methodology.