某石油炼制企业VOCs排放源强反演研究

选取我国北方某石油炼制企业为研究对象,针对其挥发性有机物(VOCs)排放,于春季3月开展了厂界周边大气VOCs环境浓度监测,并利用ISCST-3空气质量模型反推出该企业VOCs排放源强.监测结果表明,厂外上风向背景点与下风向受体点TVOCs浓度平均值分别为28.6×10-9和88.3×10-9,且2个区域VOCs还存在化学组分特征差异,背景点以乙烷、丙烷、乙烯为主,而受体点化学组分中丙烯、异丁烷、丁烷、异戊烷、戊烷的体积浓度百分比显著上升,说明该炼油厂VOCs排放体量大,对局地环境影响显著.扣除背景点VOCs,获得了该炼油厂VOCs排放化学成分谱,其主要成分体积浓度百分比:乙烷(23.4%)、丙烷(11.8%)、丁烷(10.4%)、异丁烷(9.0%)、戊烷(5.3%)、异戊烷(6.4%)、丙烯(11.5%),成分谱特征与国内相关文献相似.ISCST-3模型反演结果显示,该炼油厂TVOCs年排放量平均值为(2201.6±1011.9) t/a,折合排放因子约0.73g VOCs/kg原油.该计算结果偏低,原因可能在于:其一,测试季节为春季,较低的环境温度致使了炼油厂挥发散逸环节的排放低于全年平均水平;其二,ISCST-3模型为扩散模型,未考虑VOCs化合物在局地范围的化学衰减.     

基于磁化水的全尾砂胶结充填体强度研究

针对某矿山全尾砂充填体抗压强度低,水泥用量大的现状,将磁化水引入全尾砂胶结充填料浆的配浆试验,通过均匀布点理论优选出最佳磁化条件,探究了磁化水-全尾砂充填体的7天、14天、28天抗压强度的变化规律以及磁化水对水泥活性的影响。研究结果表明:在磁感应强度B=1000-2000Gs,水循环流速V=1.4-2.0m/s,磁化时间T=10-20min时,磁化水-全尾砂充填模块的7天抗压强度提高19%-28%,14天抗压强度提高17%-25%,28天抗压强度提高13-15%。     

基于G1法的高危作业疲劳风险模糊综合评判

疲劳严重威胁作业安全,许多事故都直接或间接由疲劳引发。针对高危作业疲劳风险评价问题,考虑作业疲劳致因,综合运用G1法,提出高危作业疲劳风险的模糊综合评判方法。首先,根据疲劳的表现,系统分析影响高危作业疲劳的因素,以管理因素、岗位因素、作业环境、生理、心理等5个因素为准则,构建作业疲劳风险的评价指标体系。然后,应用G1法,确定指标权重,建立高危作业疲劳风险多级模糊综合评价模型,评判疲劳状况。最后,通过一个案例验证了模型方法的可行性与有效性,为综合评判高危作业疲劳发生可能性提供了一个新视角与方法。     

下向进路回采钢筋混凝土假顶稳定性分析

〗为确保下向进路采场高效安全回采,采用ABAQUS的损伤塑性模型对下向进路钢筋混凝土假顶进行稳定性分析,得到假顶的应力与位移分布规律,分别从假顶的应力分布、变形量对不同进路尺寸及假顶厚度的影响进行比较分析。结果表明,进路假顶产生的最大拉应力（089MPa）小于混凝土层的抗拉强度（127MPa）;最大压应力（416 MPa）小于混凝土层的抗压强度（119MPa）;假顶底部最易被拉裂位置为偏离假顶中央(05~1)m处;钢筋承载了大部分拉应力,受拉性能得到充分利用。在进路尺寸为3m×3m或者4m×3m时假顶厚度取06m,进路尺寸为4m×4m时假顶厚度取08m,假顶最大拉应力值均未超过混凝土的抗拉强度值,此时假顶较为稳定,便于进路维护与提高回采强度。研究结果对下向进路采场的安全生产提供技术保障。     

API Standard 521 new alternative method to evaluate fire relief for pressure relief device sizing and depressuring system design

Since the 1950's, API Standards have provided guidance on determining relief loads for equipment exposed to pool fires. The API method is empirical based on tests performed in the 1940's. There is increasingly widespread interest in analytical methods based on heat transfer principles to model fire heat input. The API committee agreed to include an analytical method in the 6th edition of API Standard 521 to establish relief loads for pressure relief devices and to design depressuring systems for the fire scenario. The analytical method provides more flexibility than the empirical method but has limitations (e.g., too many permutations are possible leading to potential under-sizing of the pressure relief device).This paper discusses the basis for the empirical method in API Standard 521 and provides comparisons of the empirical and analytical method with two more recent large-scale pool fire tests. This pool fire test data indicates that the empirical method will provide a conservative estimate of pool fire heat input for most applications and is still the method of choice when designing pressure relief systems. However, these recent tests indicate the empirical method needs to be modified when a vessel or equipment is partially confined by adjacent embankments or walls equal or greater than the vessel height. In such cases, the wetted area exponent should be 1.0 instead of 0.82.The analytical method is useful in determining time-versus-temperature profiles for heating unwetted vessels of varying wall thicknesses and materials of construction. These profiles, which depend upon the type of fire (e.g., unconfined pool fire, jet fire, etc.), can be combined with tensile strength and stress-rupture data to specify a depressuring system's pressure-versus-time profile. This will minimize failure and/or mitigate the effects of failure due to overheating from fire exposure.     

火电厂锅炉再热器联络管裂纹分析及处理

某火电厂亚临界锅炉墙式再热器蒸汽出口至屏式再热器联络管母管及排空气管接管座产生裂纹发生渗漏.通过对墙式再热器出口管道排空气管接管座裂纹特征、结构型式、管道现场布置情况、运行环境等方面进行综合分析,认为排空气管道安装布置不合理,无保温措施,导致冷凝水倒流,形成热疲劳裂纹并逐步延伸扩展.确认产生裂纹的原因后,优化管道安装布...     

Leaching characteristics of bisphenol A from epoxy-resin pavement materials

We investigated the leaching characteristics of bisphenol A (BPA) from two kinds of epoxy-resin pavement materials, one containing epoxy resins (EPs) and the other containing epoxy-acrylate resins (EPAs). Both samples contained residual BPA monomer, at levels of 9.0?µg?g^?1 for the EP resin sample and 4.4?µg?g^?1 for the EPA resin sample. These amounts were larger than amounts previously measured for polycarbonate samples. The amount of BPA leached from the samples increased with temperature. The leaching of BPA from EP was more strongly affected by temperature than the leaching from EPA. The pH also affected the amount of leached BPA. The maximum leached amount was observed under alkaline conditions (pH 10.8) for both sample types. The amounts of BPA that might leach from pavement materials during 1?h of heavy rain were estimated to be 0.9?µg?m^?2 for EP and 3.5?µg?m^?2 for EPA. Our results indicate that EPs disposed of in waste landfills without any treatment may be a source of BPA in leachate at landfill sites.     

不同环境因子对黑土胶体在饱和多孔介质中运移特性的影响

为评价不同环境条件下黑土胶体在地下水多孔介质中的运移,采用离心法对采自于黑龙江海伦黑土样品中的胶体颗粒进行提取. 通过胶体在石英砂填充柱中的淋溶试验研究了pH、离子强度和溶解性有机质等环境因子对胶体在多孔介质中运移特性的影响. 结果表明:当pH在4～9的范围内变化时,MR(回收率)和k(沉积速率系数)没有发生显著变化,即其对胶体运移能力影响不显著. 随着离子强度从0.001 mmol/L升至1 mmol/L,黑土胶体穿透曲线MR降低,k值升高,说明高无机离子强度使胶体易于沉积在石英砂表面,运移能力降低. 当溶液中含有溶解性有机质HA(胡敏酸)和FA(富里酸)时,MR降低,k值增加,表明胶体运移能力受到抑制,并且FA对胶体颗粒运移的抑制作用比HA强. 溶液离子强度、HA和FA含量对黑土胶体在饱和多孔介质中的运移过程影响较大,是影响地下水中胶体运移过程的关键环境因子.      

基于Phase2的不同配比充填体厚度的数值模拟研究

在充填体作用机理,稳定性分析与监测,爆破地震效应,静动态特性及损伤理论等方面的研究基础上,依托安庆铜矿高阶段大直径深孔采矿法第一步骤采场的充填现状,采用Phase2软件建立了多种数值分析模型对不同灰砂比充填体厚度的充填效果进行数值模拟研究,并进行了多方案技术经济对比分析。研究结果表明:灰砂比为1∶4,1∶8,1∶10对应充填体厚度分别为10,24,22 m时,为最优方案。该充填体厚度可为矿山采场充填配比设计、充填管理及充填质量提供技术参考。     

考虑峰后软化的圆形巷道稳定性分析及工程应用

为获得更准确的巷道围岩应力分布和变形特征,基于统一强度理论,考虑围岩塑性软化和中间主应力的影响,引入塑性软化参数,推导出巷道围岩弹塑性区应力、塑性区范围和位移的表达式。通过算例分析,得到塑性软化系数和中间主应力等相关参数对巷道围岩应力分布、塑性区半径和位移的影响规律。研究结果表明:随内摩擦角软化系数和黏聚力软化系数的增大,围岩塑性区半径和位移呈现先急剧后缓慢的减小趋势;中间主应力系数对巷道围岩弹塑性应力有着显著影响,中间主应力系数越大,围岩塑性区半径和位移越小。