Prevention of an atmospheric storage tank bund failure

Secondary containment (bunds, drip trays, interceptors/sumps) is an integral part of many chemical, petrochemical, as well as agricultural, food and pharmaceutical facilities. Bunds are the built-in cases for accidental liquid substance spillage where there is a hazard that a substance could leak into the surroundings and the potential of health or environmental damage. The authors focus on the cases installed in large-volume atmospheric tanks storing hazardous chemicals in liquid form, where the bund failure occurred. In the first part of the study, a database of these accidents was created, numbering a total of 15 items. Attention was paid to the course of the accident, its causes and consequences. Several basic representative scenarios of bund failure have also been developed. The second part of the study is devoted mainly to the measures against the bund failure, such as risk assessment, technical and organizational measures. The aim of this study is to provide readers (including experts in the field of safety engineering, maintenance experts and building designers) with the information that can subsequently be used in the risk assessment of bund failure, possibly also for planning the construction of new bunds, or revitalization and maintenance of the existing ones.     

连续流双室微生物燃料电池处理工业废水

以实际中药废水作为阳极基质、实际含镉废水作为阴极电解液,构建了连续流双室微生物燃料电池(MFC),考察了其产电性能及对两种废水的处理效果。78 d的运行数据表明:系统可实现最大输出电压417mV、最大体积功率密度11.8 W/m3,最大体积功率密度运行条件下的库伦效率为18.5%;在阳极进水有机物浓度变化较大的情况下,实现了阳极对中药废水中有机物的有效去除,平均COD去除率为81.5%;阴极对含镉废水中Cd2+的去除率为79.4%～84.8%。这表明MFC同步处理中药废水及重金属废水具有一定的可行性。     

Study on the dynamic response of polyurea coated steel tank subjected to blast loadings

Steel tanks are widely used in the storage of various chemical liquids, and the blast resistance of the tanks is very important because of the explosiveness of these liquids. To explore a feasible method to improve the blast resistance of steel tanks, the effect of polyurea coating on the blast resistance of steel storage tank is investigated in this paper. The responses of monolithic steel tanks and polyurea coated tanks under blast loads are studied by field blast experiments using TNT explosive, and the results shows that the polyurea layers are effective in reducing the maximum and residual displacements of the tank. Numerical simulations are performed and validated, and the deformation process and stress and strain distribution of the tanks are analyzed accordingly. The increase on the bending moment of the plastic hinge lines of the tanks and the increase of the area density of the cylindrical shell induced by the polyurea layers are believed to be the two main factors contributing to the displacement reduction effect of polyurea in this paper. The validated numerical model is used to study the influence of polyurea layer's thickness on the deflection of the tank, and a nearly inversely proportional relationship between the thickness and the maximum displacement is found. Three deformation modes of the tanks are identified when subjected to blast load with varying intensity and it is found that the displacement reduction effect of polyurea varies in different deformation modes.     

基于疲劳累积破坏机制的储罐结构动力可靠度分析

针对随机风载荷作用下储罐结构动力可靠性问题，以300 m3的中小型立式低温储罐为研究对象，利用AR模型进行数值模拟得到风载荷的脉动风速时程与脉动功率谱密度函数。采用ANSYS建立储罐三维有限元模型，并对储罐进行动力学分析，计算出储罐结构的随机响应，进而求出随机风载荷作用下储罐结构动力可靠性所需全部数字特征，最后利用疲劳累积损伤机制计算得到储罐的动力可靠度。结果表明:假设结构强度不随时间退化，前5 a动力可靠度基本保持不变，随着使用年限的延长，动力可靠度下降速度明显增大。研究方法可为储罐的动力可靠性及寿命预测提供一定的理论依据。     

Characteristics of stable biodiesel emulsion fuel with the aid of lipophilic surfactant,polyglycerol polyricinoleate (PGPR)

ABSTRACT

Biodiesel emulsion fuel is reported as one of the most feasible options capable of generating lower NOx emission than that from fossil fuels. However, oil and water in the emulsion fuel are easily separated and unstable. The aim of the present study is to consider the production and stability of biodiesel emulsion fuel by using tetraglycerin ester (CR-310), i.e., one of lipophilic surfactant, polyglycerol polyricinoleate (PGPR) and biodiesel, i.e., Waste cooking Oil Methyl Ester (WOME) produced based on waste cooking oil. The corresponding heat rate, water content, and viscosity are measured. Emphasis is placed on the effects of water content and surfactant on biodiesel emulsions. It is found that: (i) stable emulsion fuel is obtained by adding at least 2.0% of CR-310 and is maintained over 1 month, (ii) there is no effect of water content on stable emulsion fuel if CR-310 is used over 2.0%, and (iii) the viscosity of emulsion fuels is higher than that of the biodiesel fuel and is gradually increased with an increase in the water content.     

基于虚拟碰撞试验分析燃料电池轿车车身结构的安全性

在燃料电池轿车的车身结构配合动力驱动系统的改进而不断改进的过程中,需要从碰撞安全性角度去分析结构方案的优劣.本文采用虚拟正面碰撞试验方法,研究经过改进后的燃料电池轿车的半承载式车身是否满足国家被动安全法规,并通过与第1代燃料电池轿车的整车碰撞模拟结果的对比,分析车身结构改进对正面碰撞安全性的影响,从而为进一步的结构改进提供有价值的建议.     

大气14CO2的时空分异特征及其在化石源CO2示踪中的应用

大气CO₂中放射性碳同位素(¹⁴C)的水平可以反映化石源CO₂的影响程度,这对于评估我国目前化石源CO₂的排放状况和制定节能减排政策具有重要的指导意义。本文在概述大气¹⁴CO₂采样和分析方法的基础上,简要介绍了大气¹⁴CO₂观测的起源和主要的源汇过程,重点论述了大气¹⁴CO₂的时空分异特征及其驱动因素;阐述了化石源CO₂浓度的估算方法及¹⁴CO₂在国内外化石源CO₂示踪中的应用现状,并对大气¹⁴CO₂观测在我国化石源CO₂示踪中的应用前景进行了展望;旨在为我国正确地开展大气¹⁴CO₂的观测研究,深刻地理解特定区域大气¹⁴CO₂的时空分异特征和化石源CO₂的分布状况提供参考。     

车用燃料环保管理——《2013年中国机动车污染防治年报》（第V部分）

环境保护部日前发布《2013年中国机动车污染防治年报》,公布了2012年全国机动车污染排放状况。本期“研究成果展示”专栏以六篇形式连载。本文刊载关于车用燃料环保管理的内容,以飨读者。该年报指出。2012年,全国实施车用汽油国Ⅲ阶段标准,硫含量不超过150ppm。按照国家强制性标准《车用汽油》（GB17930—2011）要求,自2014年1月1日起,全国实施车用汽油国IV阶段标准,硫含量不超过50ppm。2012年,我国车用柴油生产和销售执行《车用柴油》（GB19147—2009）标准和《普通柴油》（GB252—2011）标准。按照规定,车用柴油硫含量不得超过350ppm,2013年7月1日后普通柴油硫含量将不得超过350ppm。在已发布第四阶段车用汽油标准（硫含量不大于50ppm）的基础上,由国家质检总局、国家标准委尽快发布第四阶段车用柴油标准（硫含量不大于50ppm）,过渡期至2014年底;2013年6月底前发布第五阶段车用柴油标准（硫含量不大于10ppm）,2013年底前发布第五阶段车用汽油标准（硫含量不大于10ppm）,过渡期均至2017年底。加快国内炼油企业升级改造,确保按照汽、柴油标准升级实施时间如期供应合格油品。2012年环境保护部发布的《关于加强储油库、加油站和油罐车油气污染治理工作的通知》指出,按照国务院批复的《重点区域大气污染防治“十二五”规划》要求,列入大气污染防治“重点控制区”的地区,应限时完成加油站、储油库、油罐车的油气回收治理;大气污染严重的地区可根据本地实际,提前完成油气污染治理工作。     

鞍钢钢绳厂生产污水处理的工艺设计及运行效果

本文介绍了鞍钢钢绳厂生产废水处理工艺,包括沉淀系统、气浮系统、砂滤罐过滤系统。通过试验确定p H为11时,沉淀系统对Zn2+的去除率达到98.4%。通过正交试验确定当PAC用量为20 mg/L、PAM用量为2 mg/L、p H 7.5、气浮压力为1.2 Mpa时气浮系统对钢绳厂废水中SS、石油类、COD的去除率分别达到90%、70%、70%。经过砂滤罐过滤系统后废水中的SS为20 mg/L、石油类为2 mg/L、COD为48 mg/L,其去除率分别达到94%、78%、80%。     

Improved models of failure time for atmospheric tanks under the coupling effect of multiple pool fires

Fire accidents of chemical installations may cause domino effects in atmospheric tank farms, where a large amount of hazardous substances are stored or processed. Pool fire is a major form of fire accidents, and the thermal radiation from pool fire is the primary hazard of domino accidents. The coupling of multiple pool fires is a realistic and important accident phenomenon that enhances the propagation of domino accidents. However, previous research has mostly focused on the escalation of domino accidents induced by a single pool fire. To overcome the drawback, in this study, the failure of a storage tank under the coupling effect of multiple pool fires was studied in view of spatial and temporal synergistic process. The historical accident statistics indicated that the accident scenario of two-pool fires accounted for 30.6% in pool fires. The domino accident scenario involving three tanks is analyzed, and the typical layout of tanks is isosceles right triangle based on Chinese standard “GB50341-2014”. The thermal response and damage of a target tank heated by pool fires were numerically investigated. The volume of 500 m³, 3000 m³, 5000 m³ and 10000 m³ were selected. Flame temperature was obtained by FDS, and then was input onto the finite element model. The temperature field and stress field of target tanks were simulated by ABAQUS. The results showed that the temperature rise rate of the target tanks under multiple pool fires was higher than that under a single pool fire. The failure time of the tank under the coupling effect of multiple fires was lower than that under the superposition of multiple fires without the first stage. The stress and yield strength were compared to judge the failure of the target tank. The model of failure time for the tank under the coupling effect of pool fires was established. Through the verification, the deviation of this model is 4.02%, which is better than the deviation of 15.76% with Cozzani's model.