添加剂升温烧蚀法在制备新型介孔水环境净化材料中的应用

首次探索了一种破坏式造孔与有机复合相结合的新方法以制备介孔复合水环境净化材料,使最终产品成为一种具有广谱孔结构分布的复合环境材料。详细介绍了该方法的第二步工艺即添加剂升温烧蚀法,在优化后的最佳条件下,产品的孔径得到了进一步扩大,其中部分孔道直径可达至介孔级,同时材料的表面得到了进一步活化。经此步工艺后,所制备的中间产品染料吸附量是原材料的194倍,是酸洗刻蚀后产品的122倍;24h吸湿率是原材料的38倍,是酸洗刻蚀后产品的19倍。     

Investigative consequence analysis: A case study research of beirut explosion accident

Around 15:00 GMT on August 4th, an explosion occurred in the warehouse facility storing Ammonium Nitrate (AN) at Beirut port, Lebanon. The explosion resulted in more than 178 fatalities and injured more than 6500 people, and also left an estimated 300,000 people homeless and registered as an equivalent to a 3.3 magnitude earth quake. The accident was considered to be the largest of its kind and the most severe anthropological disaster of the decade, the financial loss the nation was subjected to post the explosion was estimated to be around $ 15 billion as informed by the governor. The storage conditions of ammonium nitrate at Beirut port is not definitively known to anyone, and there is no documentation provided so far from the authorities regarding the same. This work focuses on the investigation & consequence analysis of the explosion using TNT equivalent approach. The overpressure and the impulse obtained from TNT calculations are used in probit models to assess the damages caused on human beings and structures. The results obtained in this investigative approach are then utilized to provide an analytical inference relative to the damage proxy map reported by the advance rapid imaging analysis team from NASA. Also, this work examines the existing standards, fire safety measures and legal regulations for ammonium nitrate facilities in the region. AN explosion during storage like other fire and explosion accidents are definitely preventable owing to the technological advancements and developments to prevent or extinguish controllable fires. The significance of this work relates to the methods for calculation of consequences of explosion that are happening due to the storage of highly hazardous explosive materials in excessive quantities and insists the necessity of incorporating adequate safety measures while storing such reactive and hazardous materials.     

Coupling effects of the explosion shock wave and heat radiation on the dynamic response of a fixed-roof tank

The occurrence of leakage in large tank farms or oil deposits can lead to fire or explosion accidents. Coupling effects of fire and explosion loadings can cause considerably more damage to adjacent tanks or buildings than either loading individually does. In this study, the combined loadings of the explosion shock wave and heat radiation from a pool fire on a neighboring empty fixed-roof tank were numerically investigated. The effects of the explosion shock wave intensity and relative height of the explosion center [the ratio of the height of the explosion center to the height of the tank (h_r)] were analyzed. The results indicate that tanks damaged by explosion shock waves have decreased fire resistance and critical buckling temperature. Moreover, the thermal buckling deformation of the predamaged tank largely depends on the explosion shock wave. With an increase in the explosion shock wave intensity or a decrease in h_r, the explosion shock wave has greater influence on the fire resistance of the tank, and the critical buckling temperature decreases. This paper can provide an understanding of the dynamics of a tank under explosion shock wave loading, and of the critical failure criterion and failure modes of a target tank under the coupled loading of the explosion shock wave and an adjacent pool fire.     

PAN dust explosion inhibition mechanisms of NaHCO3 and Al(OH)3

We investigate the PAN dust explosion inhibition behaviors of NaHCO₃ and Al(OH)₃ in a 20 L spherical explosion system and a transparent pipe explosion propagation test system. The results show that, in the standard 20 L spherical explosion system, the highest PAN dust explosion concentration is 500 g/m³, the maximum explosion pressure is 0.661 MPa, and the maximum explosion pressure increase rate is 31.64 MPa/s; adding 50% NaHCO₃ and 60% Al(OH)₃ can totally inhibit PAN dust explosion. In the DN0.15 m transparent pipe explosion propagation test system, for 500 g/m³ PAN dust, the initial explosion flame velocity is 102 m/s, the initial pressure is 0.46 MPa, and the initial temperature is 967 °C; adding 60% NaHCO₃ and 70% Al(OH)₃ can totally inhibit PAN dust explosion flames. Through FTIR and TG analyses, we obtain the explosion products and pyrolysis patterns of the explosion products of PAN dust, NaHCO₃, and Al(OH)₃. On this basis, we also summarize the PAN dust explosion inhibition mechanisms of NaHCO₃ and Al(OH)₃.     

Effect of the vent burst pressure on explosion venting of rich methane-air mixtures in a cylindrical vessel

The effect of the vent burst pressure on explosion venting of a rich methane-air mixture was experimentally investigated in a small cylindrical vessel. The experimental results show that Helmholtz oscillation of the internal flame bubble of the methane-air mixture can occur in a vessel with a vent area much smaller than that reported by previous researchers, and the period of Helmholtz oscillation decreases slightly when the vent burst pressure increases. The maximum overpressure in the vessel increases approximately linearly with the increase in the vent burst pressure; however, the pressure peaks induced by Helmholtz oscillation always remain approximately several kilopascals. The external flame reaches its maximum length in a few milliseconds after vent failure and then oscillates in accordance with the pressure oscillation in the vessel. The maximum length of the external flame increases, but its duration time decreases with the increase in the vent burst pressure.     

Internal short circuit and accelerated rate calorimetry tests of lithium-ion cells: Considerations for methane-air intrinsic safety and explosion proof/flameproof protection methods

Researchers with the National Institute for Occupational Safety and Health (NIOSH) studied the potential for lithium-ion cell thermal runaway from an internal short circuit in equipment for use in underground coal mines. In this third phase of the study, researchers compared plastic wedge crush-induced internal short circuit tests of selected lithium-ion cells within methane (CH₄)-air mixtures with accelerated rate calorimetry tests of similar cells. Plastic wedge crush test results with metal oxide lithium-ion cells extracted from intrinsically safe evaluated equipment were mixed, with one cell model igniting the chamber atmosphere while another cell model did not. The two cells models exhibited different internal short circuit behaviors. A lithium iron phosphate (LiFePO₄) cell model was tolerant to crush-induced internal short circuits within CH₄-air, tested under manufacturer recommended charging conditions. Accelerating rate calorimetry tests with similar cells within a nitrogen purged 353-mL chamber produced ignitions that exceeded explosion proof and flameproof enclosure minimum internal pressure design criteria. Ignition pressures within a 20-L chamber with 6.5% CH₄-air were relatively low, with much larger head space volume and less adiabatic test conditions. The literature indicates that sizeable lithium thionyl chloride (LiSOCl₂) primary (non rechargeable) cell ignitions can be especially violent and toxic. Because ignition of an explosive atmosphere is expected within explosion proof or flameproof enclosures, there is a need to consider the potential for an internal explosive atmosphere ignition in combination with a lithium or lithium-ion battery thermal runaway process, and the resulting effects on the enclosure.     

Fire and explosion hazards during filling/emptying of tanks

Loading and unloading operations produce 8% of all accidents which occur in process plants and in the transportation of hazardous materials. A survey of 738 accidents was performed, allowing the identification of the accident type distribution and of their cause. Some considerations on flammable mixtures are also presented, and the procedures to avoid these mixtures occurring when filling or emptying a tank are briefly discussed.     

爆破毒气及其控制

爆破毒气是爆破五大公害之一,本文通过理论分析对其产生、传播机理进行了探讨,并提出了相关的控制技术。     

爆炸焊接的安全评估和安全防护措施

根据爆炸焊接的装药特点,对爆炸焊接炸药的使用、爆炸产生的地震波、毒气、噪音等的安全性进行了分析,给出了定量的计算公式,同时还针对不同的爆破危害,提出了相应的安全防护措施