煤及其燃烧产物中砷的分布特征

首先研究了我国各主要聚煤区煤中砷的分布,煤的砷含量均值高于世界但低于美国,低于或接近我国土壤砷含量,但与地壳克拉克值比较,砷在煤中被明显富集。从各聚煤区情况看,砷的含量和富集因子均有中新生代煤最大,华南二叠纪煤为次,而华北石炭——二叠纪煤最小的特点。煤各级燃烧产物中砷分布研究表明,底灰中亏损,但富集于飞灰特别是细粒飞灰的表面,质量平衡率的计算显示砷大多能截留于飞灰中,呈蒸气状态逸散入大气的有限。      

煤矿安全生产调度指挥信息系统及其应用

介绍了煤矿安全生产指挥信息系统的由来、组成、特点、功能及其效果与前景。该系统以对煤矿安全生产指挥决策信息支持为目的 ,集矿山安全、工况监测及生产调度信息的采集、实时传输处理、图像 /图形显示、图形和数据存储管理及输出为一体 ,已在平煤集团公司多个矿区安装使用 ,产生了较好的经济效益及社会效益。     

基于神经网络的煤与瓦斯突出预测模型

在全面分析了煤与瓦斯突出影响因素的基础上 ,提出了煤与瓦斯突出预测的人工神经网络模型。介绍了突出特征指标的选取及表示方法与推理过程。实例分析表明 ,模型精度很高 ,可用于工作面煤与瓦斯突出预测 ,并分别给出图 2 ,表 3,文献 5     

粉煤灰资源化特性及路面工程应用技术研究

对粉煤灰的各项技术参数进行了试验研究,揭示出粉煤灰的不同成分和形貌对其资源化特性的影响规律,初步完成了消除不利于粉煤灰资源化的有害成分炭的优化实验工作,进行了脱炭粉煤灰混凝土配合比等试验研究,并在路面修复工程中予以应有,结果表明,经脱炭处理的粉煤灰应用于混凝土工程可以明显改善混凝土的工作性能,实际道路运营和技术性能符合路面工程的要求,具有重大的经济效益和环境效益。     

重金属化学活性评估方法准确性质疑--以煤矸石样品为例

重金属元素化学活性的大小是决定它们环境行为最主要的因素之一,我们曾分别用总量法,实验模拟法,环境地球化学法和化学形态分析法对煤矸石样品所含的重金属元素进行过环境影响分析,试图了解自然风化条件下这些有害元素潜在的生态环境效应,结果发现重金属元素的化学活性除了与它们在样品中含量的高低,赋存状态和化学形态等因素有关外,更主要地是取决于样品基质的组成和结构,由于大量有机质的络合和风化过程中生成的铁的胶体的吸附,从煤矸石释放出的重金属元素的化学活性受到明显限制,它们对环境的污染可能仅限于煤矸石堆周围有限的范围。     

堆放参数对瑞安矿煤堆自燃风速的影响

为确定瑞安矿煤堆自燃的环境风速,提高煤堆自燃的预判能力,使用COMSOL Multiphysics 5.0数值仿真软件,开展了5个不同尺寸分别在孔隙率0.2~0.6和环境风速0.05 m/s~13 m/s条件下堆放180 d的自热-自燃过程数值模拟。结果表明,煤堆自燃风速范围因孔隙率和堆放参数不同而异,孔隙率越小煤堆的自燃风速范围越宽,且最小、最易、最大自燃风速与孔隙率之间具有幂函数关系;影响煤堆最小、最易、最大自燃风速显著的参数分别为顶宽、底宽、高度、角度和孔隙率、孔隙率、高度和孔隙率,并构建了三个自燃风速的合理解算方程。     

Porous silica synthesis out of coal fly ash with no residue generation and complete silicon separation

● Both amorphous and crystalline silicon are completely separated from coal fly ash. ● Porous silica is synthesized out of coal fly ash. ● No residues is produced during the whole synthesis process. ● The one-step method to synthesize silica don’t need long-time reaction and aging. Ordered mesoporous silica materials exhibit enormous potential in industrial production. Since coal fly ash (CFA) is abundant in Si, it has become a green and promising way to utilize CFA by synthesizing porous silica materials. However, the stable crystalline structure of CFA limits the extraction of Si, and the residue is generated during the process of extracting Si. In this work, we proposed a no-residue method to synthesize ordered mesoporous silica out of CFA. Sodium carbonate (Na₂CO₃) was used to reconstruct the crystals of the CFA, and the calcined mixture then directly reacted with the precipitators. This method combined the process of Si extraction and porous material synthesis. In this method, no residue was generated and the silicon in both amorphous and crystalline phases of CFA was fully utilized. By this method, the extraction efficiency of Si was increased from 31.75% to nearly 100%. The as-synthesized mesoporous silica had a highly-ordered pore structure with a space group of la-3d, a surface area of 663.87 m²/g, a pore volume of 0.41 cm³/g, and an average pore diameter of 2.73 nm. The mechanism of crystalline transformation and material structure formation were systematically studied. This method provides a new idea to dispose of CFA and synthesize porous silica materials.     

Disposal of Coal Fly Ash at A Deep Water Site in the Eastern Mediterranean Off Israel - Six Years of Monitoring

Coal fly ash (CFA) is dumped at a deep sea disposal site (1,500m water depth) in the eastern Mediterranean, ca. 70km off the Israeli shore. Since 1989, about one million tons of CFA were dumped at the 200km² allocated area. Six years of monitoring at the dump-site shows that the CFA is heterogeneously distributed; there are areas where CFA covers about 1.3cm depth of the sea floor while at others no CFA is found. CFA is present as a fine powder, small aggregates and even as large blocks both in the dump-site as well as at its peripheries. Cadmium, copper and zinc concentrations in the CFA decreased as a result of the prolonged contact with sea water at in situ conditions while inconclusive changes in mercury, iron and manganese were detected. No changes were observed for lead, iron and aluminium concentrations. A controlled long term field experiment, now in progress at the site, is expected to clarify further chemical changes occurring in the CFA.     

The O₂-enriched air gasification of coal, plastics and wood in a fluidized bed reactor

The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography-mass spectrometer (GC-MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery.     

Bioprocess technology for coal washery effluent treatment by Lemna minor

Duckweed species are promising macrophytes that can be used in wastewater treatment due to their rapid growth, ease of harvest, low fiber feed potential, and high protein contents. Waste‐water contaminants that are likely to be generated during washing of coal are total suspended solids (TSS), chemical oxygen demand (COD), acidity or alkalinity (pH), and metallic contaminants. Bioprocesses were developed to evaluate the potential of duckweed (Lemna minor) to treat coal washery effluent (CWE) as well as to study the impact on the biochemical changes of the Lemna minor. CWE samples were diluted with distilled water (DW) in different ratios as follows: T1‐CWE:DW(20:80%), T2‐CWE:DW(40:60%), T3‐CWE:DW(60:40%), T4‐CWE:DW (80:20%), T5‐CWE (100%), and Control‐DW(100%). The electrical conductivity of the effluent treated with Lemna minor was 0.035 deciSiemens per meter (dS/m) in the control at Day 10 and substantially higher at treatment ratios of 100, 80, and 60 percent (1.754, 1.842, and 1.631 dS/m). The highest amount of TSS was observed at test ratio T5 (38,834 mg/L), followed by T4 (28,816 mg/L), T3 (26,970 mg/L), T2 (15,320 mg/L), T1 (4,524 mg/L), and control (424 mg/L). Total hardness was higher (820 mg/L) in T4 compared to the control (220 mg/L). Total hardness of the effluent decreased after 30 days of incubation in all the treatment aliquots. The CWE at 20 percent concentration increased the duckweed population and no adverse impacts on its growth were observed. At higher concentration (T5) total mortality of Lemna minor was observed. The chlorophyll production was determined to be inversely proportional to the effluent concentration. Based on this study, it is concluded that Lemna minor can be used for treating CWE after dilution with fresh water.