加油站油气回收系统VOCs泄漏FID现场检测方法及效果分析

油气回收系统密闭点VOCs泄漏质量分数值是衡量加油站是否存在超标排放的重要指标。为提高加油站VOCs泄漏检测的时效性、代表性与准确性,采用FID现场检测方法对郑州市某加油站油气回收系统进行了检测,全方位对比分析了实验室气相色谱法与现场检测法的检测时效性、准确性,提出了密闭区域检测及质量保证和控制建议,并根据实际检测数据分析了易泄漏点。结果表明：采用FID现场检测方法对油气回收系统密闭点进行检测,能使检测成本降低90%,检测效率提高 15 倍;在现场检测前完成仪器的校准、响应时间的测定与精密度的验证工作,可使VOCs最大质量分数偏差维持在5%以下,这进一步验证了FID现场检测方法测量的准确度;油气回收系统泄漏点的确定及现场检测流程和步骤的优化,可有效提高检测数据的代表性;检测设备的定期校准,可确保FID示值相对误差在±10％范围内,响应时间不超过30 s,从而为检测质量控制提供保障;为确保泄漏点完好,结合实际检测工作,应采用液位仪自动计量技术,加强设备的维护保养并设置加油枪气液比为1.05～1.15。综上所述,在保证FID的准确性与稳定性的前提下,采用FID现场检测方法对油气回收系统VOCs泄漏质量分数进行检测具有时效性强、准确度高、数据代表性强等优势。本研究结果可为加油站采用FID现场检测油气回收系统VOCs泄漏的质量分数提供参考。     

连续起伏管道投产过程中的气相运移研究

为应对山区液体管道在投产过程中可能出现的气阻、超压问题,从气相运移角度出发,建立液顶气模型,研究在1个U型单元内积气形成、压缩和破碎的全过程,在此基础上,提出连接各个U型单元的气相的传递函数,探讨背压累积因素下,连续起伏管道投产过程中各个U型管段的积气情况和压力的变化,进行动态的建模和计算.以国内某原油管道的现场投产数...     

Experimental study on explosion inhibition by heptafluoropropane and its synergy with inert gas

The inhibition effect of heptafluoropropane (CF₃CHFCF₃) on methane explosions under different inhibitor concentrations in a closed vessel was studied. A high-speed camera and a pressure sensor were adopted respectively to record flame propagation characteristics and pressure data. Results indicate that the relationship between flame propagation and pressure rising was correlated. As the equivalent ratio (ϕ)≤1, the pressure presented a trend of rising firstly and then decreasing with increasing CF₃CHFCF₃ concentration, and it was found that there existed a critical concentration for pressure decrease. As ϕ > 1, the pressure exhibited a decreasing trend. Although the pressure appeared to seemingly increase, the moment that the pressure began to rise (t_rise) and the moment that the maximum explosion overpressure appeared (t_Pmax) were obviously delayed. The average rate of pressure rise ((dP/dt)_ave) was decreased as the concentration of CF3CHFCF3 increased. It indicates that CF₃CHFCF₃ can effectively reduce the explosion reaction rate. The critical concentration of CF₃CHFCF₃ for complete inhibition was determined. Meanwhile, the synergy of CF₃CHFCF₃-inert gas can improve the inhibition effect. Compared with CF₃CHFCF₃–N₂, the synergy of CF₃CHFCF₃–CO₂ presented a better inhibition effect, and the inhibition effect was increased with increasing inert gas concentration. And the mechanisms of physical and chemical effects on explosion inhibition were analyzed.     

System dynamics research of non-adaptive evacuation psychology in toxic gas leakage emergencies of chemical park

Chemical industry park plays an important role in optimizing the allocation of resources, but an emergency may make a great deal of personnel casualty and property loss. Many casualties are not the result of accidents but are caused by extreme behavior because of the non-adaptive psychology of the evacuees. Panic is one of the non-adaptive psychological behaviors during an evacuation, which is influenced by a variety of factors. Based on the consideration of the disaster environment and the evolution of crowd emotion, a system dynamics model of panic spread is established by using Anylogic software, and simulation experiments are carried out for different disaster severity, visibility, and groups. The results show that the number of people with severe panic increase when visibility decreases or disaster diffuses. Besides, the appropriate proportion of groups can effectively reduce the cooling time of crowd and ease the fears. However, continue to increase the number of groups has no significant effect on the panic control. This work can provide some reasonable guidance for regional emergency evacuation in chemical park.     

全球液化石油气运输网络贸易社区特征及其演化分析

液化石油气在全球清洁能源消耗市场中扮演着极为重要的角色,其通过船舶在不同港口之间进行运输,而港口之间通过局部密集的运输关系,形成了联系极为紧密的贸易社区。采用复杂网络社区探测方法,基于2013—2017年全球液化石油气船舶轨迹大数据构建运输网络,并对其贸易社区特征及其演化趋势开展分析。结果表明:(1)液化石油气(Liquefied Petroleum Gas,LPG)贸易社区内的港口之间的联系更加紧密,不同社区内的枢纽港口联系也日益紧密;(2)各个贸易社区的规模呈现出增长趋势,且同一社区内的港口在地理空间上变得更为集聚;(3)亚太地区、中东、西北欧和地中海地区形成的社区在全球LPG贸易中一直保持着重要地位,而随着时间推移,美洲社区已逐渐从一个相对孤立的社区发展成为与其他社区存在紧密联系的社区。     

趋势分析法评价苯系物标准气体的时间稳定性

根据GB/T 15000.3—2008设计了苯系物标准气体的时间稳定性研究方案,制备了4瓶苯系物标准气体,随着时间的推移进行测定并将结果制图,结果显示量值随时间没有显著的变化趋势。以线性关系为模型,计算线性直线的斜率和斜率的标准偏差,用t检验判断斜率是否显著来评价标准气体的稳定性。计算结果显示,所有斜率均不显著,因此该研究制备的苯系物标准气体能够稳定保存22个月。根据时间稳定性数据计算由不稳定性引起的不确定度,并讨论了这种计算不稳定性引起不确定度的方法对结果有放大的可能性。     

典型脱硫工艺对燃煤锅炉烟气颗粒物的影响

脱硫是燃煤锅炉的重要除污环节,为探究脱硫工艺对烟气颗粒物的影响,选取4台不同脱硫工艺(石灰石/石膏法、炉内喷钙法、氨法和双碱法)的燃煤锅炉,利用再悬浮采样法和稀释通道采样法分别采集脱硫前后烟气颗粒物样品,并测定颗粒物中的水溶性离子、无机元素和碳组分.结果表明,脱硫剂对烟气PM_2.5的组分构成产生影响,烟气经过石灰石/石膏法脱硫后,PM_2.5中的Ca由5.1%提高至24.8%;经过氨法脱硫后,PM_2.5中NH⁺₄的质量分数由0.8%提高到7.3%;双碱法脱硫则使烟气PM_2.5中Na由0.9%提高到1.7%.湿法和干法脱硫工艺的作用显著不同,湿法脱硫排放颗粒物的离子含量较高,经过石灰石/石膏法和氨法脱硫,PM_2.5中SO₄ ^2-的质量分数分别由2.0%和6.7%提高到9.6%和11.9%,Cl^-分别由0.4%和1.2%提高到3.8%和5.2%,而Cr、 Pb、 Cu、 Ti...     

预浓缩与GC-MS联用分析垃圾填埋场恶臭气体

采用预浓缩与气相色谱-质谱联用,建立了垃圾填埋场几种恶臭气体的分析方法。该法用SUMMA罐采集垃圾填埋场臭气,经预浓缩系统冷凝浓缩后,用GC-MS分析测定。几种臭气的检出限均低于3.0×10-3mg/m3,经6次重复测定,其相对标准偏差低于10%。该法已用于西安市江村沟垃圾填埋场臭气的采样分析。该法的应用增强了西安市对臭气的监测分析能力。     

恶臭源厂界空气中恶臭物质监测技术要点及结果分析探讨——以西安市某大型垃圾填埋场为例

建立了水杨酸-次氯酸钠法分析氨的标准曲线,通过对西安市某垃圾填埋场的实地监测,探索了恶臭气体中氨气的分析方法。分析了臭气、氨气、硫化氢之间的浓度相关性,利用本次监测数据,找出了针对该垃圾处理场的高浓度氨气样品初步分析方案。恶臭产生的主要点位为垃圾场渗滤液污水处理站及下游区域,垃圾场臭气呈现出由点源污染(作业面)到面源污染扩散的态势。     

离子色谱法测废印刷电路板真空热解气相污染物中HBr、NO2和SO2

在淋洗液中加入H2O2和三乙醇胺配制成吸收液,通过离子色谱法同时测定废印刷电路板真空热解气相产物中HBr、NO_2和SO_2的含量,方法简单、快速、准确。当用50 m L吸收液、采样体积为30 L时,3种污染物的检出限分别为0.000 005 7、0.000 003 4、0.000 002 9 mg/L。该方法加标回收率为95.7%~104.8%,完全能满足废印刷电路板真空热解气相污染物中HBr、NO_2和SO_2的同时测定要求。利用该方法和行标方法同时测定环境空气中的HBr、NO_2和SO_2,再利用Excel分析工具对测定数据进行F检验和t检验,检验结果表明2种测定方法无显著差异。