A new prediction method for dust explosion venting at high static activation pressures

Venting is an effective way to prevent harmful dust explosions, but the existing prediction methods are imprecise and are suitable only for applications with low activation pressures. A new method is proposed for predicting pressures based on an analysis of energy losses at high activation pressures and verified by aluminum dust explosion experiments. Compared with the experimental results, the results of the new model are relatively stable under working conditions with different activation pressures and venting areas. Based on the analysis of energy losses, the changes in the energy loss rate, temperature, and venting velocity during venting are found to be asynchronous. The thermal energy loss, which accounts for over 80 percent of the total, is expected to be larger than the kinetic energy loss. The thermal energy loss rate changes rapidly during venting, while the kinetic energy loss rate remains relatively stable. The new model is more accurate than the NFPA68 standard, which fails to consider the thermal energy loss. Neglecting the thermal energy loss may result in an underestimation of the pressure reduction; this error increases with decreasing activation pressure.     

Study on leak-acoustics generation mechanism for natural gas pipelines

In order to figure out the principles of acoustic leak detection for natural gas pipelines, a study on the leak-acoustics generation mechanism is carried out. The aero-acoustics generation mechanism is analyzed and when leakage occurs the wave equations of sonic sources are developed. The leak-acoustics generated by the quadrupole and dipole sonic sources are then simulated to obtain the laws of the acoustic characteristics. The simulation data are compared with the experimental data to verify the simulation accuracy under variable operating conditions. The results show that the quadrupoles and the dipoles generated by turbulent fluctuations cause leak-acoustics; the main component of pressure perturbations acquired by the dynamic pressure sensor is acoustic perturbations; both the simulation method and the experimental method can be applied to study the leak-acoustics generation mechanism of natural gas pipelines.     

Numerical simulation and study on the transmission law of flame and pressure wave of pipeline gas explosion

Based on FLUENT simulation software, the laws of transmission of flame and pressure wave in pipeline gas explosion were studied. It turned out that, the maximum pressure value of the explosion point is not the maximum value of the whole explosion process; the maximum pressure value of the pressure wave lowers firstly near the explosion point, then rises to a peak, and then drops gradually; two waves divide the space in the pipeline into three sections during the gas explosion transmission. The result is basically consistent between numerical simulation and experiment, and the conclusion from the simulation provides theoretical basis for research on explosion-proof and suppression devices for underground gas pipeline, as well as for technical regulations of installation.     

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。     

符合ASME要求的承压设备焊缝超声相控阵检测（一）

结合国际权威法规AsME最新要求,研讨承压设备焊缝超声检测使用相控阵（PA）技术的重要条件和方法要领,突出该技术的工程应用实际和装置选项须知。旨在为国内承压设备推广应用PA技术、制定相应行业标准和刷新、升级UT人员的操作技能,提供有用借鉴。     

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。     

关于NB/T47012-2010中TP2管村的许用应力

许用应力的选取是强度计算的前提,TP2高效管由于加工工艺特点造成其许用应力选取与其热处理状态有关,本文通过试验对轧丝后的高效管的拉伸试验和硬度进行测试,讨论翅片加工工艺对强度和硬度的影响,并讨论了同一根TP2管材不同热处理状态的许用应力如何选取,并提出对铜合金材料,笔者认为其许用应力采用强度极限除以安全系数更加合理。     

压力容器制造监督检验常见问题及改进

压力容器制造监督检验不仅仅要对技术资料、检验与试验报告进行审查,对结果进行见证（如射线底片、压力试验等）,还要对影响容器本质安全的生产制造过程进行有效的检查、监督与控制。本文讨论了压力容器制造过程质量控制及监督检验工作中发现的一些常见问题,结合《压力容器监督检验规则》（TSG R7004-2013）的相关要求,提出了一些解决方法和改进建议。     

一起高压除氧器爆炸事故原因分析

除氧器是火力发电厂给水回热系统中的一个混合式加热器,它的作用是除去锅炉给水中的氧气和其它不凝结气体,以保证锅炉给水的品质,除氧器的安全运行是发电厂安全运行的有效保证。本文对火力发电厂一台20万千瓦机组在正常运行时除氧器突然发生爆炸事故进行分析,找出事故原因提出预防事故的措施。