非柔性连接石化储罐配管温差应力分析与对策

储罐配管在温差作用下产生热位移会导致管壁产生热应力,未采用柔性连接的配管由于热应力集中作用可能发生破漏。针对与石油化工储罐非柔性连接的配管的安全问题,应用ANSYS有限元分析软件模拟计算石化企业典型配管的热应力分布;根据不同类型配管的分析结果,提出了工程技术与管理方面的针对性安全措施。研究结果表明:温差效应对石化储罐配管热应力影响显著,随内外温差的增加,配管应力集中的区域增大,最大热应力值增大;补偿措施能够改善配管的柔性,降低配管应力;约束载荷限制配管热膨胀从而增大配管应力;三通管是多根配管接合的区域,这种复杂管道交汇处会形成明显应力集中。研究结果对于提高石油化工非柔性连接配管安全性有一定的指导意义。     

Establishment of a comprehensive analysis method for the microfaunal movement in activated sludge

Environmental Science and Pollution Research - Microfaunal identification and analysis are very complex; thus, an image analysis method was utilized in this paper to overcome the shortcomings of...     

Nitrogen removal performance and bacterial communities in zeolite trickling filter under different influent C/N ratios

Environmental Science and Pollution Research - In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent C/N ratios and aeration conditions...     

Explanation of heavy metal pollution in coal mines of china from the perspective of coal gangue geochemical characteristics

Environmental Science and Pollution Research - In the process of coal gangue surface accumulation and underground filling disposal, the heavy metals contained in coal gangue will inevitably...     

浓盐水处理技术研究进展

海水淡化技术是解决中国水资源危机的一种具有根本性的举措之一.然而随着海水淡化产业规模的增大,其产生的浓盐水的排放成了本身面临解决的问题之一.本文阐述了浓盐水的特性及其对环境的各种危害性,并对浓盐水直接排放问题进行了详细分析.介绍了国内外近年来主要处理浓盐水的方法-真空膜蒸馏浓缩技术、正渗透技术、喷雾蒸发技术、冷冻法浓缩技术.对各种处理技术的原理和特点进行了详细综述,并对其研究进展进行了归纳总结.最后对各项处理技术的应用前景提出了展望.     

The accounting method and application of CO2 emissions responsibility by the electricity sector at the provincial level in China

When accounting the CO₂ emissions responsibility of the electricity sector at the provincial level in China,it is of great significance to consider the scope of both producers’ and the consumers’ responsibility,since this will promote fairness in defining emission responsibility and enhance cooperation in emission reduction among provinces.This paper proposes a new method for calculating carbon emissions from the power sector at the provincial level based on the shared responsibility principle and taking into account interregional power exchange.This method can not only be used to account the emission responsibility shared by both the electricity production side and the consumption side,but it is also applicable for calculating the corresponding emission responsibility undertaken by those provinces with net electricity outflow and inflow.This method has been used to account for the carbon emissions responsibilities of the power sector at the provincial level in China since 2011.The empirical results indicate that compared with the production-based accounting method,the carbon emissions of major power-generation provinces in China calculated by the shared responsibility accounting method are reduced by at least 10%,but those of other power-consumption provinces are increased by 20% or more.Secondly,based on the principle of shared responsibility accounting,Inner Mongolia has the highest carbon emissions from the power sector while Hainan has the lowest.Thirdly,four provinces,including Inner Mongolia,Shanxi,Hubei and Anhui,have the highest carbon emissions from net electricity outflow- 14 million t in 2011,accounting for 74.42% of total carbon emissions from net electricity outflow in China.Six provinces,including Hebei,Beijing,Guangdong,Liaoning,Shandong,and Jiangsu,have the highest carbon emissions from net electricity inflow- 11 million t in 2011,accounting for 71.44% of total carbon emissions from net electricity inflow in China.Lastly,this paper has estimated the emission factors of electricity consumption at the provincial level,which can avoid repeated calculations when accounting the emission responsibility of power consumption terminals（e.g.construction,automobile manufacturing and other industries）.In addition,these emission factors can also be used to account the emission responsibilities of provincial power grids.     

Removal of arsenic(III,V) by a granular Mn-oxide-doped Al oxide adsorbent: surface characterization and performance

In order to remove arsenic (As) from contaminated water, granular Mn-oxide-doped Al oxide (GMAO) was fabricated using the compression method with the addition of organic binder. The analysis results of XRD, SEM, and BET indicated that GMAO was microporous with a large specific surface area of 54.26 m^2/g, and it was formed through the aggregation of massive Al/Mn oxide nanoparticles with an amorphous pattern. EDX, mapping, FTIR, and XPS results showed the uniform distribution of Al/Mn elements and numerous hydroxyl groups on the adsorbent surface. Compression tests indicated a satisfactory mechanical strength of GMAO. Batch adsorption results showed that As(V) adsorption achieved equilibrium faster than As(III), whereas the maximum adsorption capacity of As(III) estimated from the Langmuir isotherm at 25 °C (48.52 mg/g) was greater than that of As(V) (37.94 mg/g). The As removal efficiency could be maintained in a wide pH range of 3~8. The presence of phosphate posed a significant adverse effect on As adsorption due to the competition mechanisms. In contrast, Ca²⁺ and Mg²⁺ could favor As adsorption via cation-bridge involvement. A regeneration method was developed by using sodium hydroxide solution for As elution from saturated adsorbents, which permitted GMAO to keep over 75% of its As adsorption capacity even after five adsorption–regeneration cycles. Column experiments showed that the breakthrough volumes for the treatment of As(III)-spiked and As(V)-spiked water (As concentration = 100 μg/L) were 2224 and 1952, respectively. Overall, GMAO is a potential adsorbent for effectively removing As from As-contaminated groundwater in filter application.

     

Carbon dioxide emissions from cities in China based on high resolution emission gridded data

Based on the China high resolution emission gridded data (1 km spatial resolution), this article is aimed to create a Chinese city carbon dioxide (CO₂) emission data set using consolidated data sources as well as normalized and standardized data processing methods. Standard methods were used to calculate city CO₂ emissions, including scope 1 and scope 2. Cities with higher CO₂ emissions are mostly in north, northeast, and eastern coastal areas. Cities with lower CO₂ emissions are in the western region. Cites with higher CO₂ emissions are clustered in the Jing-Jin-Ji Region (such as Beijing, Tianjin, and Tangshan), and the Yangtze River Delta region (such as Shanghai and Suzhou). The city per capita CO₂ emission is larger in the north than the south. There are obvious aggregations of cities with high per capita CO₂ emission in the north. Four cities among the top 10 per capita emissions (Erdos, Wuhai, Shizuishan, and Yinchuan) cluster in the main coal production areas of northern China. This indicates the significant impact of coal resources endowment on city industry and CO₂ emissions. The majority (77%) of cities have annual CO₂ emissions below 50 million tons. The mean annual emission, among all cities, is 37 million tons. Emissions from service-based cities, which include the smallest number of cities, are the highest. Industrial cities are the largest category and the emission distribution from these cities is close to the normal distribution. Emissions and degree of dispersion, in the other cities (excluding industrial cities and service-based cities), are in the lowest level. Per capita CO₂ emissions in these cities are generally below 20 t/person (89%) with a mean value of 11 t/person. The distribution interval of per capita CO₂ emission within industrial cities is the largest among the three city categories. This indicates greater differences among per capita CO₂ emissions of industrial cities. The distribution interval of per capita CO₂ emission of other cities is the lowest, indicating smaller differences of per capita CO₂ emissions among this city category. Three policy suggestions are proposed: first, city CO₂ emission inventory data in China should be increased, especially for prefecture level cities. Second, city responsibility for emission reduction, and partitioning the national goal should be established, using a bottom-up approach based on specific CO₂ emission levels and potential for emission reductions in each city. Third, comparative and benchmarking research on city CO₂ emissions should be conducted, and a Top Runner system of city CO₂ emission reduction should be established.     

中国耕地非农化压力时空格局的演变分析

社会经济和资源禀赋的区域差异导致耕地非农化压力表现出明显的空间异质性。开展耕地非农化压力测算并揭示其时空格局演变,是实现土地资源优化配置的基础。从经济因素、社会因素、产业结构和资源禀赋4个方面构建耕地非农化压力指数评价指标体系,采用熵值法计算各指标权重,继而计算1990~2014年中国31省的耕地非农化压力指数,并在此基础上开展了耕地非农化压力的时空格局分析。结果表明:(1)从空间格局分布来看,中国耕地非农化压力空间分布呈现明显的地理梯度,总体上呈现从东到西依次递减的态势。(2)从时间变化趋势来看,不同地区各省份之间的耕地非农化压力指数变化呈现多元化趋势。东部沿海地区,山东、浙江、江苏的耕地非农化压力指数处于上升阶段,上海、福建的压力指数变化趋势逐渐趋稳,广东的压力指数呈现下降趋势。中部地区,河南、河北、山西、江西的耕地非农化压力指数趋稳,陕西、湖北以及四川、重庆等西南地区省份的压力指数呈上升趋势。西部沿边3省(云南、西藏、新疆)的耕地非农化压力呈现了一致的下降趋势。(3)从时空格局结合来看,耕地非农化压力不同的省份其变化趋势呈现出截然不同的走向。在耕地非农化压力较大的地区,耕地非农化经历了从制度驱动向发展推动的阶段,经济增长的倒"U"型轨迹明显,经济增长与耕地非农化之间的关系逐渐脱钩。在耕地非农化压力居中或较小的地区,产业发展滞后,土地比较收益较低,耕地的社会保障作用、生态作用对耕地非农化的影响较大,从而增加了部分省份的耕地非农化压力。