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1.
氮是煤中的常见元素之一,煤中氮的赋存形态多样且随煤阶发生变化。以邯郸-峰峰矿区为例,利用X射线光电子能谱(XPS)实验,研究不同变质程度煤(Rran=1.08%~3.67%)中有机氮的赋存形态,探讨煤中各形态有机氮相对含量随煤阶的变化规律。结果表明:按N 1s XPS谱图分峰峰值的结合能可将煤中氮的形态归为N-6、N-5、N-Q和N-X四种;研究区煤中N-5的相对含量最高,且随着煤阶的增高而降低;N-Q的相对含量随着煤阶的增高而增高;煤中N-6的相对含量随煤阶呈“增-减-稳”的变化规律;N-X的相对含量为9.1%~35.1%,其与煤阶关系不明显;在煤阶Rran=1.08%~1.47%的范围内,煤的N 1s XPS谱图中缺失N-Q分峰,表明褐煤中相对含量最高的质子化吡啶氮在此阶段已几乎全部去质子化而转化为吡啶氮。不同变质阶段氮的赋存形态变化特征对燃煤发电及煤化工领域煤化学参数选取提供参考。   相似文献   

2.
综述了煤中氮的赋存状态与氮含量的分布特征方面的研究现状及存在问题。认为,煤中的氮几乎全部以有机物的形式存在,其赋存状态主要有4种类型:吡咯型氮(N-5)、吡啶型氮(N-6)、季氮(N-Q)和氮氧化物(N-X),且这四种含氮官能团的分配比例受煤阶和煤热解程度的影响。煤中氮的质量分数一般在0.5%~2.5%,其变化与煤级、成煤期、沉积环境、原始成煤植物、煤岩组成及岩浆侵入等因素有关。目前有关影响氮含量变化因素的研究主要集中在探讨氮的含量与煤级的关系上,并认为氮的含量随煤级升高而增大,但在煤化作用后期迅速降低。有关氮的研究可丰富煤的元素地球化学研究,并为煤的环境污染治理提供更多的科学依据。   相似文献   

3.
gd15N-values and nitrogen contents of a series of humic and bituminous organic sediments of different ranks were determined. The change of the isotopic abundance of nitrogen was investigated during heating in model experiments, using a gas flame coal.In the case of humic carbon coals the relative nitrogen contents vary from 0.8 to 1.4% and the δ15N-values from +3.5 to +6.3%. increasing from the brown coal to anthracite ranks. During the coalification process both the δ15N-values and the relative nitrogen contents do not vary continuously with the rank, but pass through maxima and minima. Model experiments using a gas flame coal show the same trend. Nitrogen with δ15N-values of +2.8 or ?7%. was released in pyrolysis experiments, applying a gas flame coal and a steam coal at temperatures of 650 and 1000°C, respectively.The investigated bitmuinous sediments yielded relative amounts of 0.1 to 0.8% with δ15N-values of + 4.2 to + 10.7%.The obtained results are discussed with respect to the elucidation of nitrogen genesis in natural gas deposits.  相似文献   

4.
通过对晋东南和豫中地区几个煤矿矸石堆及其周围的土壤和水体、井下矸石取样分析,发现这些矿的煤矸石中全氮的背景值为0.4%~0.8%。在中高煤变质程度地区,含铵伊利石夹矸中全氮高达1.0%~1.6%,铵伊利石的存在对于矸石堆中全氮含量的提高具有贡献。在矸石山周围积水中,具有较高的氮含量,说明雨水比较容易从矸石堆中将氮淋滤出来。煤矸石堆周围土壤中的氮含量并不高,说明煤矸石淋滤物并没有发生明显的横向迁移,可能主要表现为垂向渗透,有可能对地下水造成潜在的氮污染。   相似文献   

5.
Recent advances in electron microprobe technology including development of layered synthetic microstructures, more stable electronics and better matrix-correction programs facilitated routine microanalysis of the light elements in coal. Utilizing an appropriately equipped electron micro-probe with suitable standards, it is now possible to analyze directly the light elements (C, O and N, if abundant) in coal macerals and other kerogen. The analytical results are both accurate compared to ASTM methods and highly precise, and provide an opportunity to access the variation in coal chemistry at the micrometre scale. Our experiments show that analyses using a 10 kV accelerating voltage and 10 nA beam current yield the most reliable data and result in minimum sample damage and contamination. High sample counts were obtained for C, O and N using a bi-elemental nickel-carbon pseudo-crystal (2d = 9.5 nm) as an analyzing crystal.Vitrinite isolated from anthracite rank coal proves the best carbon standard and is more desirable than graphite which has higher porosity, whereas lower rank vitrinite is too heterogeneous to use routinely as a standard. Other standards utilized were magnesite for oxygen and BN for nitrogen. No significant carbon, oxygen or nitrogen X-ray peak shifts or peak-shape changes occur between standards and the kerogen analyzed. Counting rates for carbon and oxygen were found to be constant over a range of beam sizes and currents for counting times up to 160 s. Probe-determined carbon and oxygen contents agree closely with those reported from ASTM analyses. Nitrogen analyses compare poorly to ASTM values which probably is in response to overlap between the nitrogen K α peak with the carbon K-adsorption edge and the overall low nitrogen content of most of our samples.Our results show that the electron microprobe technique provides accurate compositional data for both minor and major elements in coal without the necessity and inherent problems associated with mechanically isolating macerals. Studies to date have demonstrated the level of compositional variability within and between macerals in suites of Canadian coals.  相似文献   

6.
天津临港经济区地处滨海, 完全是由填海造陆形成的人工陆地。土壤是港口航道清淤淤泥、近海海沙吹填围海造陆后形成的吹填土, 其性质特殊, 研究吹填土壤中氮磷空间分布对了解该区域环境状况有重要意义。研究发现:天津临港吹填土整体含氮量较低, 按土层深度分布, 平均质量分数为161.73~240.09 mg/kg;含磷量相对丰富, 平均质量分数为355.54~443.27 mg/kg;总氮变异系数较大, 总磷变异系数较小, 氮、磷质量分数主要受不同区域吹填土性质影响。吹填土中有机磷质量分数较少, 平均仅占总磷的3.83%, 吹填土中磷大多以无机磷形式存在, 其相对质量分数从大到小为:钙结合磷(Ca-P) >铁结合磷(Fe-P) >铝结合磷(Al-P) >闭蓄态磷(Oc-P) >碎屑磷(De-P) >交换态磷(Ex-P)。研究表明, 临港吹填土氮、磷质量分数水平对近海环境有潜在富营养污染威胁。  相似文献   

7.
土壤中的氮素是植物生长发育的基础,由于城市湿地土壤受特殊水文条件影响,土壤全氮(TN)的分布规律和影响机制较为复杂,因此研究土壤TN的空间分布特征具有重大的生态意义。本文以再生水为主要补给水源的北京门城湖湿地公园为研究区,运用ArcGIS和地统计学对该区土壤TN的空间分布特征进行研究。结果表明:研究区土壤TN质量分数较高,差值明显,变异系数达47.35%;比较不同的植物群落区可知,香蒲群落区土壤TN质量分数最高。对影响研究区土壤TN分布的因素分析得出:土壤TN、全磷(TP)质量分数呈极显著正相关关系(r=0.81,P0.01);TN、土壤有机质(SOM)质量分数呈显著正相关关系(r=0.62,P0.05);气候因子中,湿度和温度对TN分布同样影响显著。水质参数中,再生水出水口处测得的土壤TN的指标数值更高,随出水口距离的增加,参数值总体呈下降趋势且逐步趋于稳定,说明植被对湿地土壤中氮素空间分布的调整具有重要作用。  相似文献   

8.
煤的微观孔隙结构特征是煤储层特征的重要研究内容之一。选取黄陇侏罗纪煤田转角勘查区4个典型低阶煤样品为研究对象,以煤质特征研究为基础,进行压汞和液氮吸附实验,获取了不同测试方法的煤孔隙结构参数。根据两种测试方法的优缺点在孔径50nm处采用曲线拼接法进行联合,分析了全孔径段的比表面积和孔隙体积分布。结果显示:煤的比表面积主要分布在微孔、小孔和中孔三个区间,呈现“三峰”特征,表现为微孔>小孔>中孔>大孔的分布特征;孔隙体积主要分布在微孔、小孔和大孔。灰分含量和阶段孔径比表面积和孔隙体积具有较好的相关关系,但相关性强弱不同,总体显示和微孔、小孔及中孔呈正相关关系,而与大孔孔隙呈负相关关系,灰分含量与微孔、小孔的影响最大。显微组分中的镜质组和壳质组含量与大孔比表面积和孔隙体积呈正相关关系,与微孔、小孔呈负相关关系;惰质组含量与大孔孔隙比表面积和孔隙体积呈负相关关系,和微孔、小孔呈正相关关系。  相似文献   

9.
以贵州某高硫煤样为研究对象,该煤样原煤灰分27.00%,硫分3.35%。通过对原煤硫的物相进行分析,硫的赋存状态主要以硫化物硫为主,其分布率占到73.07%。进行了单一摇床工艺研究,获得的精煤产率73.27%,精煤中硫分1.30%,灰分15.39%。试验结果表明,仅采用工艺较为简单的单一摇床工艺就可达到对原煤高效的脱硫降灰目的。  相似文献   

10.
Measured were the abundance and distribution of nitrogen in glasses of glass inclusions in olivines of CV3, CO3, CR, C4, CH3, and LL chondritic meteorites by means of the 14N(d, p)15N nuclear reaction. Similar to what was observed with carbon, nitrogen is present in low concentrations (<20 ppm) in the structure of olivines but can by stored in variable amounts in glasses of glass inclusions. These primitive glasses, characterized by a Si-Al-Ca-rich composition, have highly variable nitrogen contents (30 to 1500 ppm) and highly inhomogeneous nitrogen distribution. Nitrogen contents are independent of the chemical composition of the glasses. The heterogeneous distribution is a common feature of all studied inclusions, as is evidenced by the variable contents of nitrogen in glass inclusions occurring in the same olivine grain. Nitrogen heterogeneity is suggestive of trapping of solid nitrogen carrier phases during formation of the constituents of chondrules. However, part of the originally trapped nitrogen appears to have been lost, possibly, by ulterior oxidation and subsequent transformation into volatile species.  相似文献   

11.
济宁煤田煤中氯的分布、赋存及富集因素研究   总被引:1,自引:1,他引:0  
氯是煤中普遍存在的一种元素, 氯的含量与分布影响着煤的加工与利用.通过对济宁煤田各主要可采煤层中氯含量的分析可知, 研究区属低氯煤层, 氯含量的高低及分布与煤层空间位置、成煤植物、沉积环境和地下水活动等因素有着重要的关系.同时, 对氯在煤中的赋存状态进行了研究, 通过氯与有机显微组分、灰产率等指标的相关性计算, 得出研究区煤中的氯与有机显微组分成正比, 与灰产率成反比, 说明氯主要存在于煤的有机质中, 并且主要是存在于镜质组分的微孔隙中.   相似文献   

12.
Nitrogen and phosphorus content ofSpartina alterniflora Loisel and soil nitrogen were measured along a transect perpendicular to a stream in a Louisiana salt marsh in order to provide information on differences between the so-called streamside and inland regions. Total plant nitrogen and phosphorus levels in June and September tended to be greater at streamside than inland sites. Total soil nitrogen on a dry soil weight basis increased with distance inland from a natural stream toward an interdistributary basin in the marsh. Soil extractable ammonium-nitrogen levels measured in June were very low in vegetated streamside and inland areas, but they were much higher in inland areas devoid of plants. Nitrogen and phosphorus utilization byS. alterniflora was also investigated at an inland location in the salt marsh. Labelled ammonium-nitrogen and phosphate-phosphorus were added in May at a rate of 200 kg/ha to the soil of replicated plots. Added nitrogen significantly increased total above-ground plant biomass and plant height by 28 and 25%, respectively, 4 months after application. The ratio of belowground macro-organic matter to total aboveground biomass was decreased from 5.7 to 4.7 by the additional nitrogen. Added phosphorus did not significantly affect plant height and biomass. The use of15N-depleted nitrogen tracers showed that about half of the nitrogen in the aboveground portion ofS. alterniflora from 1 to 4 months after the nitrogen addition was derived from the added ammonium-nitrogen. After 4 months, 28 and 29% of the added labelled nitrogen was recovered in the aboverground and belowground biomass ofS. alterniflora, respectively. Recovery of added nitrogen was overestimated with a non-tracer method based on the difference in total nitrogen uptake between nitrogen-amended plots and untreated plots. Soil organic nitrogen comprised the majority of the nitrogen in the salt marsh. Nitrogen in the standing crop biomass ofS. alterniflora represented only about 2% of the total nitrogen in the plantsoil system of an inland marsh to a 20 cm soil depth.  相似文献   

13.
对云南省昭通地区晚二叠世C5煤层硫分和灰分进行测试及资料分析,编制了C5煤层硫分分布等值线图,分析了硫分、灰分分布特征及相关关系等。结果表明:研究区硫分大于1%的硫分赋存状态主要为硫铁矿硫,有机硫次之,硫酸盐硫最少;硫分分布主要受到成煤环境的控制,自西向东逐渐由陆相过渡为滨海相,硫分含量呈逐渐增加的趋势,而灰分分布与硫分呈负相关关系。在研究区中部陆相向滨海相过渡地带的洛旺向斜,硫分与灰分相对适中,是优质煤炭资源的有利勘探开发区。  相似文献   

14.
节水条件下土壤氮素的环境影响效应研究   总被引:4,自引:0,他引:4       下载免费PDF全文
王康  沈荣开 《水科学进展》2003,14(4):437-441
土壤无机氮素的损失主要是铵氮的挥发损失和硝氮的反硝化和淋失.土壤水分和氮素含量的增加,都将增加氮肥淋失的潜在威胁,如处置不当,获得高产可能需要以环境的污染为代价.节水条件下土壤无机氮素的损失量有所减少,但是氮素利用效率也同时受到了土壤水分状况的限制.探讨了作物产量、氮素损失和农业生产要素(水分、氮素)实际投入量之间的关系,建立了节水条件下土壤氮素损失和环境评价概念型模型,通过在北京水利科学研究所永乐店灌溉试验站3年的试验资料对模型进行了参数求解及校验.  相似文献   

15.
Conclusions Some bituminous coals, mostly of high volatile rank, sampled from various coalfields contained on average 0.5 m3 t–1 nitrogen and 0.13 m3 t–1.Nitrogen is released more readily than methane during coal winning but the volumes of nitrogen released are small compared with ventilation quantities and are only likely to be of significance for detailed oxygen deficiency studies.  相似文献   

16.
After the sewage treatment, putting the wet sludge in which the heavy metal content is extremely low, corrupt and broken straw, bentonite, urea in proportioning according to the certain ratio, mixing well-distributed, taking the shape of Nitrogen slow-release fertilizers, doing the dynamic bioleaching test by the method of Artificial rainfall simulation, researching the slow-release characteristic, water retention. When the mass ratio of the wet sludge whose water content is 82.5%: bentonite: corrupt and broken straw: urea is 62.5: 12.5: 12.5: 12.5, drip washing the 10g Nitrogen slow-release fertilizers by the 80ml distilled water after 48h, the residue rate of urea is 29.63%; Under the room temperature of 25 ℃, 77%RH, moisture evaporate 46.32% after 60 h. The results demonstrate that the slow-release fertilizer has a good release-effect of nitrogen and water conservation effect. It provides the basic for the development and application of the sewage in the aspect of Nitrogen slow-release fertilizers.  相似文献   

17.
贵州六枝、水城煤田晚二叠世煤的微量元素特征   总被引:4,自引:0,他引:4  
通过对六枝和水城煤田 10个煤矿主要可采煤层的 45个煤样品的常量和微量元素系统研究 ,概括了这两个煤田煤中常量和微量元素的丰度和分布特征 ;阐述了煤中微量元素的亲合性。这两个煤田煤中的全硫含量在受海水影响的煤层中较高 (最高达 7.5 % ) ,而在非海水影响的煤层中较低 ( 0 .3% )。六枝煤田的全硫含量明显高于水城煤田。Ca-Mn-Ge的平均含量在六枝煤田较低 ,而在水城煤田相对较高。在这两个煤田和不同的煤层之间 ,煤中微量元素含量的变化较小。与世界烟煤中一般含量范围相比 ,这两个煤田的特征是 Mn,V,Cu,L i,Zr,Nb,Ta,Hf,T1,Th和 U的含量相对高。  相似文献   

18.
采用标准试验方法求得筑坝用煤矸石的最大干密度和相应的最优含水量。试验结果表明,击实作用使煤矸石的粗大颗粒发生破碎,导致其粒度组成改变,颗粒级配进一步趋于良好,有利于碾压密实。当粗粒质量分数大于60%时,煤矸石的破碎程度明显提高。当粗粒质量分数小于40%时,煤矸石的工程特性主要由细颗粒的性质决定。煤矸石的渗透系数和孔隙比之间存在指数关系。随细颗粒含量的增加,煤矸石的渗透性将显著降低。  相似文献   

19.
通过对重庆地区煤炭资源勘查资料总结,分析了二叠系煤类分布特征,并探讨了煤变质对煤层含气量的影响。分析认为,重庆地区二叠系煤层主要以高、中变质煤的无烟煤、贫煤和瘦煤为主,煤类分布具有明显的分带性,煤变质作用以区域深成变质类型为主;煤的变质程度R0为1.39%~2.51%,处于吸附能力较强的阶段,因此煤层含气量较高,其中松藻矿区无烟煤R0为2.43%~2.51%,煤层含气量达27.1m3/t。  相似文献   

20.
煤系烃源岩不同极性溶剂抽提物生物标志物特征   总被引:2,自引:0,他引:2  
煤的氯仿抽提物族组成和生物标志物分布特征与煤系原油存在很大差别,导致含煤沉积盆地中煤系原油的油源确认十分困难。采用正已烷、苯、二氯甲烷、氯仿4种不同极性溶剂对9个煤系烃源岩和3个典型湖相烃源岩的抽提实验表明,随着溶剂极性的增加,抽提物的含量逐渐增加,其中饱和烃所占的比例明显逐渐减少,正已烷抽提物的组成与煤成油的组成最相似。尽管不同溶剂获得的抽提物的量和组成存在明显差异,但是其正构烷烃、类异戊二烯烷烃和甾萜类生物标志物分布特征总体上比较相似,没有显示出某一种溶剂抽提物中某种烃类的明显富集或者减少。正已烷和氯仿抽提物中生物标志物绝对含量(浓度)分析表明,正已烷抽提物中中生物标志物的绝对含量相对较低,而氯仿抽提物中相对较高,煤系源岩之间的差异较大,而湖相泥岩之间差异较小。10个烃源岩样品的正已烷抽提物和氯仿抽提物中18种主要生物标志物相对含量的统计分析显示,同一标志物之间相对误差小于 5%(包括实验分析误差在内)的占84%,相对误差大于10%的不足5%。这一结果表明抽提溶剂的极性差异可以导致煤的抽提物中饱和烃相对含量与生物标志物绝对含量的变化,但是在通常使用的抽提溶剂极限范围内,不会导致抽提物中生物标志物分布特征和相互比值的变化。从而也不会影响应用生物标志物进行油源对比的结果。使用常规溶剂氯仿抽提煤等高有机质丰度烃源岩所获得的生物标志物可应用于煤系含油气盆地的油源对比。  相似文献   

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