球接管容器气体爆炸尺寸效应的试验研究与数值分析

为了解尺寸对球形容器连接管道甲烷-空气混合物爆炸的影响规律,利用Fluent软件,采用κ-ε湍流模型、涡耗散模型(简称EDC模型)、壁面热耗散、热辐射模型及SIMPLE算法,建立了球形容器连接管道内甲烷-空气混合物爆炸的数值模型,对容器与管道内甲烷-空气预混气体爆炸的尺寸效应进行了数值模拟。结果表明:随管道内径增大,球形容器内最大爆炸压力逐渐增大,管道末端最大爆炸压力变化无明显规律;而随管道长度增加,球形容器内最大爆炸压力逐渐减小;改变管道内径,较大体积球形容器内最大爆炸压力均大于较小体积球形容器内最大爆炸压力,最大爆炸压力上升速率的规律则相反,容器体积对管道末端最大爆炸压力的影响无明显规律。     

压力容器安全操作要点浅议

压力容器根据各自的特点和在生产工艺流程中的作用 ,都有其特定的操作程序和操作方法。尽管各种压力容器的使用工况不尽一致 ,却有共同的安全操作要点。从操作的角度 ,说明如何预防安全事故。     

船舶造成大气污染的控制

根据MARPOL 73/ 78公约附则Ⅵ《防止船舶造成空气污染规则》 ,结合陆上有关大气污染防治技术 ,对船舶造成大气污染控制的现状进行讨论 ,并对中国在该附则生效前应做工作提出了建议     

快开门式压力容器余压开门爆炸数值仿真研究

据统计,快开门式压力容器爆炸事故约占压力容器事故总数的三分之一,且带压开门是引起爆炸的主要原因,因此针对其安全开展相关研究具有重要的意义。基于此,该文建立了快开门式压力容器余压爆炸数值计算模型,并进行了数值计算。计算结果(包括压力分布、速度分布、温度分布等)能直观显示快开门式压力容器爆炸过程。数值结果与试验结果进行了对比,结果表明,该模型具有较高精度,可以有效的预测快开门式压力容器的开门余压爆炸。     

工作环境改变后在役压力容器的检验

介绍了使用环境异常变化后,压力容器重新检验的必要性及相关的检验内容和技巧。     

压力容器的风险管理

压力容器的本质安全直接关系石油化工等行业的HSE本质,而HSE核心理念的风险管理又决定着压力容器的本质安全。结合锅炉水预热器腐蚀泄漏的案例,对压力容器的本质安全与HSE的风险管理从设计、制造到使用管理全程进行了分析解读,认为压力容器的本质安全取决于设计、制造直至使用管理全过程风险管理的践行,由此给出了合理化建议。     

Dust particle sedimentation in the 20 L standard vessel for dust explosion tests

According to the current international standards, to perform the correct evaluation of the explosion and flammability parameters, a uniform distribution of the dust particles should be achieved inside the 20 L and/or 1 m³ standard vessels.CFD simulations have shown that in both standard test vessels (20 L and 1 m³), the dust particles are not uniformly dispersed, being mostly concentrated at the edge of the macro-vortices generated by the injection of the fluid and particle through the nozzle. In addition, only a partial fed of the particles is obtained, and dust particles sedimentation phenomena can occur.As a result, the dust participating to the reactive process may be much lower than the expected nominal concentration in the vessel due to sedimentation and incomplete feeding. Consequently, misleading values of the flammability/explosion parameters could be measured.Particle sedimentation and incomplete feeding depends both on the Stokes number and on the Reynolds number, whereas the concentration distribution depends on the turbulence level, the fluid flow maps, and the number of particles which enter into the vessel through the nozzle.The aim of this work is to evaluate the key parameters (particle size, particle density, and fluid velocity) affecting sedimentation and incomplete feeding in 20 L vessel. To this end, CFD simulations of dust dispersion are performed at varying the particle density and size. Operating maps, in terms of the key parameters and/or their dimensionless combinations, are developed and a correlation for correction of the data is proposed.     

长江船舶苯酚泄漏污染事故的应急监测

从方案制定、监测布点、现场工作等方面,阐述长江南通段船舶苯酚泄漏污染事故的应急监测工作。通过案例分析并比对国内其他类似事故,明确该类型事故具有污染源不确定性强、污染扩散速度快、污染影响范围广等特点。应对类似事件,通过建立应急统一指挥中心、现场应急监测实验室、模型预测等技术手段,可以提高应急监测的科学性和主动性。     

Managing Fleet Capacity Effectively Under Second-Hand Market Redistribution

Fishing capacity management policies have been traditionally implemented at national level with national targets for capacity reduction. More recently, capacity management policies have increasingly targeted specific fisheries. French fisheries spatially vary along the French coastline and are associated to specific regions. Capacity management policies, however, ignore the capital mobility associated with second-hand vessel trade between regions. This is not an issue for national policies but could limit the effectiveness of regional capacity management policies. A gravity model and a random-effect Poisson regression model are used to analyze the determinants and spatial extent of the second-hand market in France. This study is based on panel data from the French Atlantic Ocean between 1992 and 2009. The trade flows between trading partners is found to increase with their sizes and to be spatially concentrated. Despite the low trade flows between regions, a net impact analysis shows that fishing capacity is redistributed by the second-hand market to regions on the Channel and Aquitaine from central regions. National capacity management policies (constructions/destructions) have induced a net decrease in regional fleet capacity with varying magnitude across regions. Unless there is a change of policy instruments or their scale of implementation, the operation of the second-hand market decreases the effectiveness of regional capacity management policies in regions on the Channel and Aquitaine.     

Effects of used lubricating oil on two mangroves Aegiceras corniculatum and Avicennia marina

An outdoor experiment was set up to investigate the effects of used lubricating oil(5 L/m~2)on Aegiceras corniculatum Blanco. and Avicennia marina(Forsk)Vierh.,two salt-excreting mangroves.A.marina was more sensitive to used lubricating oil than A. corniculatum and canopy-oiling resulted in more direct physical damage and stronger lethal effects than base-oiling.When treated with canopy-oiling,half of A.corniculatum plants survived for the whole treatment time(90 d);but,for A.marina,high mortality (83%)resulted from canopy-oiling within 3 weeks and no plants survived for 80 d.Base-oiling had no lethal effects on A.corniculatum plants even at the termination of this experiment,but 83% of A.marina plants died 80 d after treatment.Forty days after canopy- oiling,93% ofA.corniculatum leaves fell and no live leaves remained on A.marina plants.By the end of the experiment,base-oiling treatment resulted in about 45% ofA.corniculatum leaves falling,while all A.marina leaves and buds were burned to die.Lubricating oil resulted in physiological damage to A.corniculatum leaves,including decreases in chlorophyll and carotenoid contents,nitrate reductase,peroxidase and superoxide dismutase activities,and increases in malonaldehyde contents.For both species,oil pollution significantly reduced leaf,root,and total biomass,but did not significantly affect stem biomass.Oil pollution resulted in damage to the xylem vessels of fine roots but not to those of mediate roots.