An easy method to design gas/vapor relief system with rupture disk

Tank discharge gas/vapor flow problems are frequently encountered in both practice and design. To perform this type of design calculation, the first step is to identify whether the flow is choked or not through a trial-and-error solution of an equation for adiabatic flow with friction from a reservoir through a pipe. Developing a direct method without any trial-and-error to identify a choking condition would be helpful for expediting the flow calculations. This paper presents an easy and quick method to identify the choking of gas flow for an emergency relief system consisting of a rupture disk and vent piping. This greatly simplifies the design calculations. The proposed method for validating the venting adequacy of existing ERS circumvents the iteration calculation and the use of Lapple charts. Three case studies for the design of vent piping for rupture disks support the proposed method.     

电厂烟气脱硫机组改造取消GGH可行性研究分析

介绍了石灰石一石膏湿法烟气脱硫工艺及烟气换热器（简称GGH）在烟气脱硫（简称FGD）工程中的作用,指出安装GGH产生的烟囱腐蚀和增加系统故障等问题。实践证明烟气脱硫工程取消GGH对大气环境无明显影响,并且能产生较大的经济效益。     

顶空气相色谱法测定地表水中吡啶

采用顶空进样、毛细管柱HP -INNOWAX分离、GC -FID测定地表水中吡啶。水样顶空时通过加碳酸钠盐大幅度降低了检出限 ,最低检出浓度达到 0 0 2mg/L。本法加标回收率为 96 5 %～ 10 1% ,变异系数为 7 8%～ 9 8%。     

气田开发过程中地下水环境保护方案初探

区域地下水环境的保护是气田开发过程中环境保护工作的重点之一。通过现场调查和统计分析得知,外部污染源是影响当地地下水环境的主要因素,农田径流污染源是外部的主要污染源,以COD_Cr计其排放量分别约占外部污染源排放总量的67%,而钻井液漏失、天然气窜层、钻井废水排放等钻井作业是内部的主要污染源,其COD_Cr排放量约占内部污染源COD_Cr排放总量的62%,因而钻井作业的污染防治应是项目内部地下水污染防治工作的重点。根据地下水环境质量现状分析及变化趋势分析可知由于气田的开发建设,气田区地下水水质已受到一定程度的影响,特征污染物表现为COD_Cr、氨氮、氯化物、硝酸盐氮。为保护气田区地下水环境,分施工期和运营期两阶段设计了地下水环境保护方案,采取源头控制的清洁生产,至末端控制的污染治理并提出了突发污染事故应急预案,为气田的可持续开发提供指导。     

加油站油气回收处理技术的研究及应用进展

介绍了国内外加油站油气回收处理技术现状及应用进展，阐明了国内开发的重点应是：密封加油系统及设备、吸收式油气回收装置及分散吸附集中处理系统。     

Applying a new method for direct collection, volume quantification and determination of N2 emission from water

The emission of N₂ is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al. (2013) developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N₂ and other gases. By the optimized new method, the recovery rate for N₂ was 100.28% on average; the mean coefficient of determination (R²) was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N₂ concentration as influenced by sample storage times of 1, 2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area (%) in comparison with the averaged relative peak area of each method at 0 day. The indices of the bottle full of water method were the lowest (99.5%-108.5%) compared to the indices of vacuum bag and vacuum vial methods (119%-217%). Meanwhile, the gas chromatograph determination of other gas components (O₂, CH₄, and N₂O) was also accurate. The new method was an alternative way to investigate N₂ released from various kinds of aquatic ecosystems.     

望虞河西岸九里河中四种除草剂的污染现状

基于气相色谱-质谱联用(GC-MS)法结合固相萃取(SPE)前处理技术,建立了水中4种除草剂氯草定、阿特拉津、乙草胺和异丙甲草胺残留的分析方法,于2018年春(4、5月)、秋(9、10月)和冬(1、3月)季对太湖流域望虞河西岸九里河水体中4种除草剂的污染现状进行调查分析。结果表明,4种除草剂的加标回收率为71. 2%～108%,RSD均10%,方法检出限为3. 5～6. 0 ng/L。九里河水体中氯草定、阿特拉津、乙草胺和异丙甲草胺4种除草剂质量浓度分别为未检出～0. 025 7,0. 019 1～1. 19,未检出～0. 026 0和未检出～0. 094 3μg/L。4种除草剂中阿特拉津最高值接近《地表水环境质量标准》(GB 3838—2002)限值,其他3种其值较低,氯草定首次在太湖流域水体中检出。     

气相色谱法测定水质中的内吸磷

优化了气相色谱法测定水质中的内吸磷,当取样量为100 m L时,内吸磷-O方法检出限为0. 30μg/L,测定下限为1. 20μg/L;内吸磷-S方法检出限为0. 80μg/L,测定下限为3. 20μg/L。内吸磷-O和内吸磷-S标准曲线线性良好,相关系数分别为0. 999 2和0. 999 8。不同水质中内吸磷-O的加标回收率为90. 3%～104%,相对标准偏差为3. 6%～9. 2%;内吸磷-S的加标回收率为92. 1%～94. 9%,相对标准偏差为4. 6%～8. 7%。该方法灵敏度高,能有效分离内吸磷-O和内吸磷-S,同时能将内吸磷-O、内吸磷-S与其他有机磷农药类干扰物分离。     

官厅水库沉积物表层中的有机氯农药分布特征及风险评价

采用气相色谱法对北京市官厅水库沉积物表层中持久性有机氯农药(OCPs)的残留状况进行了调查,并对有机氯农药污染水平和生态风险作出评价。结果表明:沉积物中有机氯农药总含量为8.48 ng/g～24.40 ng/g,其中HCHs和DDTs的含量较高,分别为1.11 ng/g～7.73 ng/g和2.97 ng/g～10.52 ng/g,其组分特征为来自环境的残留。与沉积物风险评估低值(ERL)和风险评估中值(ERM)对比评价沉积物中有机污染物的风险程度,官厅水库沉积物表层中的有机氯农药存在一定的生态风险。     

气相色谱法测定苯酚生产废水中芳香族化合物

建立了用气相色谱法同时测定苯酚生产废水中异丙苯、α-甲基苯乙烯、α-甲基苯甲醇、2-苯基-2-丙醇、苯酚、苯乙酮、2-苯基丙醛等7种芳香族有毒有机污染物的定量分析方法。采用二氯甲烷对水样进行萃取后进行分析测定,气相色谱条件:DB-WAX型色谱柱,FID检测器,程序升温,进样量1μL。方法的检出限、精密度、回收率实验表明,该方法对苯酚生产废水中各污染物组分具有较好的分离效果,对7种物质的检测限均低于0.05 mg/L,5次测定的相对标准偏差小于5%,实际水样的加标回收率大于97%。