Umweltrelevanz von natürlichen polyzyklischen aromatischen Kohlenwasserstoffen aus Steinkohlen – eine Übersicht

Releases of PAHs from hard (bituminous) coals into the environment have not been widely recognized. In hard coals, some hundreds of mg/kg of EPA-PAH and some thousands of mg/kg total PAH concentrations can occur and the concentrations vary significantly depending on hard coal maturity and origin. Highest PAH concentrations are present in the maturity range of the so-called “oil-window” (high volatile bituminous coal rank), however there is no general correlation. Only coals from the same origin can be compared. Naphthalene and phenanthrene as well as their alkylated derivatives are the dominant single polyaromatic compounds in hard coals. The PAH distribution patterns change with increasing rank from the low molecular weight, mostly alkylated compounds with linkage to the original organic material to the predominantly higher molecular weight parent compounds. The former are characteristic for coals of petrogenic origin and the latter for those of pyrogenic origin. Currently, PAHs from coals and from crude oil and its products cannot be distinguished by use of common simple diagnostic parameters. In countries holding large coal basins and associated mining activity, coal particles can comprise 10–15?% of the sediment or soil. Until today, little has been known about desorption and bioavailability of native PAH from coals. Literature studies so far show slow and very slow desorption and hardly any or no effects on organisms. This shows that there is a lack of systematic studies using heterogeneous coals from different countries. Bioavailability of PAH from coal particles in soils and sediments has an impact on risk assessment and should be included in sediment and soil standards.     

The distribution, occurrence and environmental effect of mercury in Chinese coals

Mercury (Hg) is a toxic, persistent, and globally distributed pollutant due to its characteristic properties such as low melting and boiling points, conversion between chemical forms and participation in biological cycles. During combustion mercury in coal is almost totally emitted to the atmosphere. With a huge amount of coal consumed, coal combustion is one of the main anthropogenic sources of this element in the environment. In this study, Hg data of 1699 coal samples of China has been compiled, and the concentration, distribution, modes of occurrence, and the impact of Hg emissions on the environment are investigated. Most Chinese coals have Hg content in the range of 0.1 to 0.3 ppm, with an average of 0.19 ppm, which is slightly higher than the average Hg content of world coals and is close to that of the U.S. coals. The Hg content in coals varies in different coal basins, geological ages and coal ranks. The most likely mode of occurrences of Hg in high-sulfur and high Hg content coals is as solid solution in pyrite. But in low-sulfur coals, modes of occurrence of Hg are variable, and the organic-bound and sulfide-bound Hg may dominate. Silicate-bound Hg may be the main form in some coals because of magmatic intrusion. Mercury emissions during coal combustion have resulted in serious environmental contamination in China, particularly in the northeastern and southwestern China, where a high Hg content in the atmosphere occurs.     

Environmental geochemistry of antimony in Chinese coals

Environmental geochemistry of antimony (Sb) has gained much attention recently because of its potential toxicity. We have reviewed the distribution, modes of occurrence, geological processes and environmental effects of Sb in Chinese coals. Data of Sb in 1058 coal samples from China were compiled and the average Sb content in Chinese coals is estimated to be 2.27 microg/g. Average Sb content in coals from provinces, cities and autonomous regions may be divided into three groups. Group 1 has a low average Sb content of lower than 1 microg/g, Group 2 has a medium average Sb content of 1-3 microg/g, and Group 3 has a high average Sb content of >3 microg/g. Coals from Guizhou and Inner Mongolia are extremely enriched in Sb. The abundance of Sb in coals differs among coal-forming periods and coal ranks. Antimony occurs in several modes in coals. It may substitute for iron or sulfur in discrete pyrite grains or occurs as tiny dispersed sulfide particles in organic matter. During coal combustion Sb is partly released to the atmosphere and partly partitioned into solid residues. Antimony in the environment brings about definite harm to human health.     

Source apportionment of PAHs in sediments using factor analysis by time records: application to Lake Michigan, USA

Apportionment of sources of polycyclic aromatic hydrocarbons (PAHs) by a factor analysis model based on time records for seven sediment cores from central Lake Michigan is reconsidered to provide a more quantitative treatment, and one additional factor (source). The effect of mixing depth was observed on the unmixed fluxes, and a computer program was developed for estimation of the average PAH fluxes from the reconstructed PAH records. The new factor analysis model with nonnegative constraints includes not only scaling but also back scaling which improved the source apportionment significantly. One core, CLM-A, was an outlier and was omitted from the analysis. Wood burning was identified as a third major source of PAHs in the area (20% of the total PAH flux). The other two sources petroleum (traffic), 45%, and coal (coke oven emissions), 35%, became more apparent, where the contributions are based on the sum of concentrations of 16 PAH compounds. A reduced mixing depth (1.0-1.5cm) was found to be more appropriate than the originally estimated mixing depth (1.5-2.0cm).     

Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. lakes

Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) has increased in the United States during the past 40 years. We evaluated sources of PAHs in post-1990 sediments in cores from 40 lakes in urban areas across the United States using a contaminant mass-balance receptor model and including as a potential source coal-tar-based (CT) sealcoat, a recently recognized source of urban PAH. Other PAH sources considered included several coal- and vehicle-related sources, wood combustion, and fuel-oil combustion. The four best modeling scenarios all indicate CT sealcoat is the largest PAH source when averaged across all 40 lakes, contributing about one-half of PAH in sediment, followed by vehicle-related sources and coal combustion. PAH concentrations in the lakes were highly correlated with PAH loading from CT sealcoat (Spearman's rho = 0.98), and the mean proportional PAH profile for the 40 lakes was highly correlated with the PAH profile for dust from CT-sealed pavement (r = 0.95). PAH concentrations and mass and fractional loading from CT sealcoat were significantly greater in the central and eastern United States than in the western United States, reflecting regional differences in use of different sealcoat product types. The model was used to calculate temporal trends in PAH source contributions during the last 40 to 100 years to eight of the 40 lakes. In seven of the lakes, CT sealcoat has been the largest source of PAHs since the 1960s, and in six of those lakes PAH trends are upward. Traffic is the largest source to the eighth lake, located in southern California where use of CT sealcoat is rare.     

辽宁新邱废弃矿山环境治理中浮煤残煤回采研究

新邱露天煤矿矿区环境治理是阜新市目前最大的民生工程,通过该项目的实施,可以改变矿区及周边生态环境恶劣的现状,同时因地制宜地构建和恢复宜人宜居的生态环境。其中,浮煤、残煤自燃治理是矿山环境治理的一个重要环节。结合矿区地形地貌,进行勘察规划设计,利用三维模型以及采矿技术手段掌握矿区浮煤、残煤分布情况,进而利用3D模型通过3D-MINE软件估算浮煤、残煤保有储量。探讨研究应用单斗卡车采掘工艺清理浮煤、削坡清理边坡残煤自燃煤层,既消除了浮煤、残煤自燃产生的火灾,又有效地回采浮煤、残煤。新邱露天煤矿矿区环境治理中浮煤、残煤的回采利用对其他露天煤矿环境治理有一定借鉴意义。     

煤矸石掺力口低品位石灰石煅烧高活性混合材的研究

将未燃煤矸石掺加低品位石灰石后,在1100℃和1200℃下进行了煅烧试验。煅烧后的改性煤矸石有C2S、C3A等胶凝矿物形成,胶凝活性提高。用作水泥混合材时,活性指数可达89％。将掺加20％石灰石的煤矸石在1200℃下煅烧,应用水泥熟料煅烧热效应计算,该种改性煤矸石的理论热耗为310kJ／kg,仅为水泥熟料理论热耗的16％。     

断裂构造对西藏煤系分布的制约

通过对西藏自治区四个比较主要的煤系的研究分析,解开了部分断裂构造对这些煤系的制约,马查拉煤系的完整性被断裂构造破坏,同时断裂构造还控制了东侧的海陆交互相的沉积分布,并为其东侧沉积盆地提供了成煤的物质条件;妥坝煤系受多个断裂构造影响,总体呈北西-南东向展布;土门煤系的断裂构造形成和发育在晚三叠世之前,控制晚三叠世形成土门煤系的沉积条件;多尼煤系的断裂构造分多种,对其分布制约较为突出,有的断裂构造形成有益于海陆交互沉积的环境,有的则是煤系形成后的改造。西藏自治区多数煤系的后期改造都有构造运动的控制作用。     

Inferences over the sources and processes affecting polycyclic aromatic hydrocarbons in the atmosphere derived from measured data

Data concerning atmospheric lifetime and relative source contributions of polycyclic aromatic hydrocarbons (PAH) are fragmentary and contradictory. In this study, two datasets of measurements of atmospheric PAH (sum of particulate and gaseous phases), one from a national network, the other from a more local three-site study, were analysed and used to infer processes affecting PAH in the atmosphere, and their sources. PAH congener profiles measured at urban and rural locations were remarkably similar suggesting that atmospheric decay processes are relatively slow. This allows the use of such profiles to elucidate sources. A spatial analysis of two PAH datasets showed a clear influence of industry and road traffic upon local PAH concentrations. When Principal Component Analysis (PCA) was applied to UK national network data, it showed a clear influence of steel industry emissions and of home heating emissions from coal and oil in Northern Ireland. These sites also showed different winter/summer concentration ratios to the main group of sites. In the data from Birmingham (UK), PCA identified separate factors relating to gasoline and diesel vehicles, as well as the influence of wood combustion on “Bonfire night”, and a factor related to home heating emissions which shows up only in the cold season.     

Emission characteristics of polycyclic aromatic hydrocarbons from combustion of different residential coals in North China

Emission properties of polycyclic aromatic hydrocarbons (PAHs) from combustion of six residential coals in North China were investigated. The results indicated that, the total emission factors (EFs) for 15 PAH species in gaseous and particulate phases ranged from 52.8 to 1434.8 mg/kg with a decreasing sequence of local bituminous coals and anthracite coals, and honeycomb briquettes were largely dependent on the raw coals used to produce them. Particulate phase, dominated by median or high molecular weight components, made a major contribution (68.8% - 76.5%) to the total EFs for bituminous coals, while gaseous phase with principal low molecular weight species accounted for most (86.3% - 97.9%) of the total EFs for anthracite coals. The phase partitioning of PAH emission for honeycomb briquettes was similarly dependent on the crude coals. The total EFs, phase partitioning and component profiles of emitted PAHs were mainly influenced by the inner components of the studied coals. Burning mode and flue number on household coal-stoves also affected the emission characteristics by means of the oxygen supply. A sum of seven carcinogenic PAHs, benzo(a)pyrene(BaP)-equivalent carcinogenic power and total toxicity potency expressed in 2,3,7,8-tetrachlorodibenzo-dioxin(TCDD) toxic equivalence exhibited that bituminous coals and produced honeycomb briquettes had remarkably elevated values. Fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene and indeno(1,2,3-cd)pyrene from anthracite coals showed higher levels of BaP-based toxic equivalent factor, though the other toxicity indices were rather low for this type of coal.     

2×7 MW锅炉房燃料管理探讨

通过对多品种煤进行化验、计算和优化 ,分析了其特性指标之所以差异很大的原因。采用了将不同种类、不同性质的煤按一定比例掺配加工的方法 ,使其达到锅炉用煤技术指标 ,以保证锅炉的安全、经济运行     

南疆三地州同一构造背景下三个盆地煤中元素特征及其地质意义

为探讨煤样品中主量元素和微量元素的差异性及其控制因素,以处于同一构造背景下南疆三地州三个盆地内的煤矿为研究对象。通过反射光显微镜、带能谱的扫描电镜(SEM-EDS)等分析测试方法,对比分析长胜(CS)煤矿、克孜库尔安(KZKEA)煤矿和莫木太来克(MMTLK)煤矿煤样品主量元素和微量元素特征的差异性。利用微量元素,如钒/(钒+镍)(V/(V+Ni))、锶/铜(Sr/Cu)和锶/钡(Sr/Ba)等比值,分别探讨了三个煤矿沉积时期的氧化还原特征、古气候和古盐度特征。研究结果表明,泥炭沼泽形成时的沉积环境和构造运动是引起同一构造背景下三个盆地煤中元素差异的主要因素。     

PAHs in sediments of the Black River and the Ashtabula River, Ohio: source apportionment by factor analysis

Sources of polycyclic aromatic hydrocarbons (PAHs) in the Black River and Ashtabula River sediments were apportioned using a factor analysis (FA) model with nonnegative constraints. Source profiles, contributions (microg/g) and percent contributions are determined with no prior knowledge of sources. The FA model includes scaling and backscaling of data with average PAH concentrations, without sample normalization. The present work is a follow-up to studies that used a chemical mass balance model to apportion sources to the same data sets. Literature source profiles, modified based on gas/particle partitioning of individual PAHs, from nine PAH sources were considered for comparison. FA results for a three-source solution indicate traffic (58%), coke oven (26%), and wood burning/coal tar (16%) are the primary PAH sources to Black River sediments. The primary PAH sources to the Ashtabula River sediments are traffic (51%), coke oven (44%), and wood burning (5%). This work supports the previous studies of Black River and Ashtabula River PAHs by CMB model. In addition, FA provides a more realistic fit to Ashtabula River model data by eliminating 100% contributions from one source.     

煤加压固定床纯氧气化的试验研究

选取1种褐煤、7种长焰煤、1种烟煤和3种无烟煤作为试验煤种,分析了各煤种的煤质特性。对各煤种在100mm加压固定床气化炉内进行纯氧气化,进行各项气化指标分析,总结各煤种加压固定床纯氧气化的一般规律。     

Use of machine learning algorithms to assess the state of rockburst hazard in underground coal mine openings

The risk of rockbursts is one of the main threats in hard coal mines. Compared to other underground mines, the number of factors contributing to the rockburst at underground coal mines is much greater. Factors such as the coal seam tendency to rockbursts, the thickness of the coal seam, and the stress level in the seam have to be considered, but also the entire coal seam–surrounding rock system has to be evaluated when trying to predict the rockbursts. However, in hard coal mines, there are stroke or stress-stroke rockbursts in which the fracture of a thick layer of sandstone plays an essential role in predicting rockbursts. The occurrence of rockbursts in coal mines is complex, and their prediction is even more difficult than in other mines. In recent years, the interest in machine learning algorithms for solving complex nonlinear problems has increased, which also applies to geosciences. This study attempts to use machine learning algorithms, i.e. neural network, decision tree, random forest, gradient boosting, and extreme gradient boosting (XGB), to assess the rockburst hazard of an active hard coal mine in the Upper Silesian Coal Basin. The rock mass bursting tendency index W_TG that describes the tendency of the seam–surrounding rock system to rockbursts and the anomaly of the vertical stress component were applied for this purpose. Especially, the decision tree and neural network models were proved to be effective in correctly distinguishing rockbursts from tremors, after which the excavation was not damaged. On average, these models correctly classified about 80% of the rockbursts in the testing datasets.     

煤岩相组分对煤表面积的影响

本文用多元回归方法，分析煤岩相组分和煤阶对煤及相对应煤焦表面形态的影响。从回归结果可以找出影响煤表面的主要因素，结果表明镜质组和煤阶对煤和煤焦表面积影响最大。壳质组对煤焦的表面影响比煤大。     

混煤热解特性及热解机理的研究

本文针对两种不同性能煤种掺配的混煤，比较了它们同单一煤的热解特性，用热重分析法研究了混煤的热解反应机理，为混煤的气化提供理论依据。     

不同性质煤的微观特性及渗透特性对比试验研究

 对从典型矿井取得的不同性质煤,分别进行微观特性和瓦斯渗透特性试验。结果表明：突出煤的比表面积和吸附/解吸能力明显高于延期突出煤和非突出煤,延期突出煤介于二者之间。突出煤吸附能力强,解吸速度相对也较快,可能形成较高的气体压力,对煤岩的破坏性增强。非突出煤的渗透率明显高于突出煤和延期突出煤的渗透率,相差最大处超过4倍以上,煤的渗透特性好,瓦斯就较易在煤层中运移,煤层的储气条件差,瓦斯更容易从煤层中脱离出来,反之则会增加突出危险性。说明渗透特性是考察煤层是否具有突出危险性的一个重要指标。总之,煤的渗透特性和微观特性是密切相关的,吸附/解吸特性能力强,煤的渗透特性相对较差,强度较低,较易发生破坏,突出危险性较大。     

不同顶煤条件下支架工作阻力的确定

从端面顶板稳定性控制角度出发 ,应用数值模拟离散元法分析了不同顶煤条件下端面顶板稳定性与支架工作阻力及端面距的关系。模拟结果表明 :在软及中硬煤条件下 ,端面距一定范围内 ,支架工作阻力P与端面顶板下沉量Δld 为类双曲线关系 ;而硬煤条件下没有类似关系。由此给出不同顶煤条件下支架工作阻力的计算方法 ,认为在软及中硬煤条件下可以利用P -Δld 关系曲线确定支架临界工作阻力 ,而传统支架工作阻力确定方法适合于硬煤条件 ,结论在实测中得到验证     

捣固炼焦的配煤试验

对不同的配合煤用试验焦炉进行捣固炼焦,捣固炼焦可以提高焦炭机械强度,改善焦炭热性质,多配高挥发分气煤。细度约90％的煤捣固炼焦效果较好。