煤中掺比伴生硫化物的自燃特性分析

为了深入探究矿井下伴生硫化物对煤自燃及着火燃烧特性的影响,向原煤中添加不同量的含硫物配制4种不同含硫量的煤样,通过TG实验、DSC测试和XRD分析,研究伴生硫化物对煤自燃及着火燃烧特性的影响规律;基于Coats-Redfern法计算煤中掺加不同伴生硫化物时煤燃烧阶段的活化能。研究结果表明:随着煤中掺比伴生硫化物的增多,煤的特征温度相应减小,而吸氧量、可燃和稳燃指数相应增大,原煤中混入伴生硫化物后更易自燃;随着煤中掺比伴生硫化物的增多,煤燃烧阶段的活化能降低,煤更易着火燃烧;伴生硫化物的主要成分为水绿矾、叶绿矾,这些物质在常温下遇水和氧气能够发生化学循环反应,反应放热促使了煤更易自燃;伴生硫化物在温度高于200℃以后整体表现为放热,在温度为565℃时达到放热峰值,这使得煤燃烧阶段的活化能降低,煤更易燃烧。     

速生杨木粉尘最小点火能的实验研究

为防止木材加工中木质粉尘燃爆事故的发生,以纤维板生产中常见的原材料速生杨木粉尘作为研究对象,在分析粉尘粒径分布、元素分析、工业分析及形貌特征的基础上,采用1.2 L哈特曼管对3种不同粒径（0~50,＞50~96,＞96~180 μm）速生杨木粉尘进行最小点火能实验,探究点火延迟时间、喷粉压力、质量浓度和粒径分布对速生杨木粉尘最小点火能的影响及变化规律。研究结果表明:在质量浓度为500 g/m3时,分别增加点火延迟时间和喷粉压力,最小点火能都先减小后增大;最佳点火延迟时间和最佳喷粉压力分别为120 ms和120 kPa;粒径对最佳点火延迟时间和最佳喷粉压力无显著影响。在点火延迟和喷粉压力分别为120 ms和120 kPa条件下,最小点火能随质量浓度的增加先减小后增大。粉尘粒径与最小点火能呈正相关性,3种样品的最小点火能分别为1~3,1~3和7~13 mJ,对应的敏感质量浓度分别为500 ,750和1 250 g/m3,属于特别着火敏感性粉尘。     

Implementing EU climate and energy policies in Poland: policy feedback and reform

European Union (EU) climate/energy targets and policies are poised for the first full climate policy cycle – from adoption and implementation of the policy package for 2020, to reform for 2030. A dynamic approach to the ways in which EU policies affect policy development is developed by applying theories of domestic implementation, policy feedback and integration. Implementation experiences in Poland – the ‘least climate ambitious’ EU member state – affected Polish preferences for reformed EU policies. Existing EU policies, their ‘fit’ with Poland’s energy interests and change in anticipation of future EU policies explain much of the variation in preferences. Second, policy feedback from Poland significantly affected the EU 2030 climate and energy framework. As yet, the EU has succeeded only partly in gathering momentum through a ‘snowball’ effect whereby positive policy feedback from implementation generates further steps.     

Negotiating energy democracy in practice: governance processes in community energy projects

There is a growing ‘energy democracy’ (ED) movement which regards the transition to renewable energy as an opportunity for socio-economic transformation, as well as technological innovation. The literature on ED tends to associate greater democratic control of energy systems with increased community control over the means of energy generation and distribution. Nonetheless, this literature often assumes rather than demonstrates that the forms of governance it promotes are more democratic than the status quo. This analysis contributes to the emerging field of ED by assessing the complex and varied ways in which communities in Scotland practise energy governance. By focusing on three key governance processes (decision-making, accountability and dispute resolution), the importance of local contexts for the establishment and negotiation of democratic practices is demonstrated. This local specificity, however, also raises further questions regarding the universal applicability of the ED concept.     

我国重点调查企业工业锅炉污染排放特征

基于中国2015年环境统计重点调查工业企业的逐台工业锅炉数据,分析了中国重点调查工业企业工业锅炉的现状、能源消耗、污染排放及治理水平等。统计数据分析表明:在能源消耗和废气污染物产生排放量上,燃煤工业锅炉占85%以上;燃煤工业锅炉规模越小,其烟粉尘排放强度越大;超过一半以上工业锅炉烟粉尘直排,烟粉尘去除率虚高;工业锅炉相对集中在东北、华北少数几个大省及热力、化工等少数几个重污染行业。对工业锅炉污染治理提出治理对策建议。     

Climate Change and Energy Technologies in Undergraduate Introductory Science Textbooks

Global climate change and the implementation of energy technologies are among the most pressing issues facing society and the environment today. Related educational content spans the science disciplines. Through an analysis of introductory-level university textbooks from four major US publishers in Biology, Chemistry, and Physics, this study presents trends in terminology and content. As the defining terms, “global warming” and “climate change” are used nearly equally. However, the first location of a working definition for climate change appears earlier. Energy technologies, climate change, and related environmental issues are found, on average, on ≤4% of textbook pages, and variation is large among individual textbooks. Discipline-based trends exist, especially for the energy technologies presented. Addressed separately as a non-renewable, non-fossil fuel, nuclear energy is found on ≤1% of textbook pages and unfavorably represented. The discussion within these science disciplines has implications on introductory-level education, public perception of science, and informed citizenship.     

Distribution,source, and ecological risk assessment of PAHs among size and density fractions in contaminated sediments from the Yellow River of Henan section

This study investigated particle size and density distributions of polycyclic aromatic hydrocarbons (PAHs) in two surface sediments (JZ and KF), collected from the Yellow River of Henan section, China. The concentrations of Σ₁₅PAHs ranged from 35.6 to 45862?ng g^?1 dry wt, which were greatly elevated in coarse particles and low-density fractions. The Σ₁₅PAHs concentrations in low-density fractions were 533 (JZ) and 996 (KF) times higher than those in the corresponding high-density fractions. However, due to relatively less quantities of low-density fractions (0.27–2.33%), most of the PAHs were contributed by the high-density components. For both sediments, the influence factors of PAHs source in the environment were very complex, more so than the level of TOC and BC content. JZ sediment was dominated by 4-ring to 6-ring PAHs (61.5–75.1%), while, 2-ring to 3-ring PAHs were abundant in KF samples (39.8–72.6%). Ratios of specific PAHs reflected PAHs among the size- and density-fraction of each sediment may be contaminated by mixed of pyrolytic and petrogenic origin. Additionally, ecological risk assessment of PAHs suggested that total toxic equivalent values of PAHs in the low-density fractions were much higher than those of the corresponding high-density fractions in the studied area.     

Trends in Raindrop Kinetic Energy with Modeled Climate Warming in the Lake Tahoe Basin

Two means by which climate change may increase surface soil erosion in mountainous terrain are: (1) increasing the frequency of extreme rainfall events and (2) decreasing the duration of snow cover on bare soil. We used output from four general circulation models (GCMs) and two greenhouse gas trajectories to produce a suite of hydrologic variables at a daily time‐step for historic and projected 21st Century conditions. We statistically disaggregated the daily rainfall to hourly, using hourly rainfall from a network of nine weather stations in the Tahoe Basin, and filtered out rain falling on a snowpack. We applied published equations to convert hourly intensity to raindrop kinetic energy (KE) for each day and grid cell in the Basin, averaged across grid cells, and created time series of total annual and maximum annual hourly kinetic energy (TKE and MKE) on snow‐free ground. Using the Generalized Extreme Value distribution, we calculated the significance of long‐term trends in KE on snow‐free ground, and estimated energy levels for return periods of 2, 20, and 100 years. We then detrended the snowpack data and compared the resulting trends in KE with the trends resulting from changes in both rainfall energy and snowpack under two GCMs. Principal findings include (1) upward trends in MKE, (2) stronger upward trends in TKE; and (3) an effect of increasing rainfall intensities on KE in some cases, and a strong effect of reduced snowpack in all cases examined.     

滆湖藻密度的时空分布及驱动因子分析

在2年内分季度调查滆湖浮游植物种群和水环境因子,分析藻密度的空间分布状况以及按时间序列的藻密度变化和浮游植物优势种群变化,分别采用"多元线性逐步回归法"和"偏相关系数法"进行藻密度驱动因子识别。结果表明,滆湖藻密度空间分布趋势为由北向南逐渐升高,年际间季节差异极显著。浮游植物的演替规律为冬、春季节以绿藻和硅藻为主,夏、秋季节蓝藻占绝对优势。通过比较2种统计方法的计算结果,确定全湖及中、南部湖区藻密度的驱动因子是温度和高锰酸盐指数,北部湖区藻密度的驱动因子是温度和硝酸盐氮,所有驱动因子对滆湖藻密度的影响均为正效应。在富营养化严重的滆湖,N,P营养盐已经不再是浮游植物生长的主要驱动因子,从统计方法的角度解释了部分环境因子没有入选为驱动因子的原因,并推断了其他可能的驱动因子。     

中国可再生能源政策演化、效果评估与未来展望

发展可再生能源已成为中国能源转型及减缓气候变化的关键途径。2006年《可再生能源法》实施至今,中国可再生发展取得举世瞩目成绩。然而可再生能源在中国整个能源结构中的占比仍然偏低,其未来可持续发展仍面临挑战,如可再生能源发展资金缺口持续扩大,可再生能源电力消纳仍然面临一定障碍。在未来新的发展背景下,有必要对中国可再生能源政策进行系统的评估和总结,进一步探讨未来可再生能源政策的优化方案。本文首先对中国2005—2019年可再生能源政策的发展历程及演化路径进行总结梳理,基于不同时期的发展特点及面临的主要矛盾将中国可再生能源政策历程划分为四个阶段;然后在综述相关研究基础上,对中国可再生能源政策的实施效果进行评估,包括政策有效性、政策成本、技术进步等。结果表明,中国过去十年的可再生能源政策对促进可再生能源快速发展是积极有效的,而促进可再生能源发展的政策成本仍然有进一步下降的空间;另外,虽然中国可再生能源发电成本下降显著,然而基于历史经验的技术进步率仍然不足以支撑实现中国2020年平价上网的目标,未来需要进一步推动可再生能源技术的进步和发电成本的下降。结合当前及未来中国可再生能源发展所处阶段的特点及面临挑战,我们提出进一步完善中国可再生能源政策以促进可再生能源持续稳定发展的政策建议,一是完善可再生能源绿色电力证书交易制度,增强可再生能源发展的内生激励并降低政策实施成本;二是建立储能技术市场机制,为减少弃电以及推动可再生能源消纳提供政策支持;三是推进碳金融体系建设,为可再生能源发展提供新的融资来源并降低发电成本。