Analysis of the boiling liquid expanding vapor explosion (BLEVE) of a liquefied natural gas road tanker: The Zarzalico accident

The impact of accidents during the transport of dangerous good, on people, the environment, and infrastructure and measures for their reduction: a review

Road transport is one of the most dangerous methods of goods transport. Driver errors and poor traffic conditions can cause traffic accidents, which can have a negative impact on people's health, the environment, and infrastructure. The main influence on the level of the consequences is the chemical composition and amount of the transported substance. This paper presents the causes of traffic accidents during the transport of dangerous goods. In addition, how traffic accidents during the transport of dangerous goods affect people's health, the environment, and infrastructure was shown. After that, measures for accidents avoidance and the alleviation and reduction of dangerous goods were given. From the review of studies from the subject field, it can be concluded that the dangerous goods are very harmful to people, the environment, and infrastructure when transport accidents occur. Lessons should be learned from the history of accidents involving the transport of dangerous goods to avoid repeating the same mistakes. The review conclusions indicate that a routes optimization and investment in road infrastructure are needed to reduce risk during the transport of dangerous goods.

Research on the Safety and Security Distance of Above-Ground Liquefied Gas Storage Tanks and Dispensers

Many countries lack clear legal requirements on the distance between buildings and petrol station facilities. The regulations in force directly determine the petrol station facilities' required distance to buildings, and such distances are considered relevant for newly designed and reconstructed buildings. Public buildings must be located no closer than 60 m to the above-ground liquefied gas tanks and liquid gas dispensers. Still, based on engineering calculations and the applied technical measures, it is possible to determine a safe distance for buildings that are constructed, extended and reconstructed, to which superstructures are added or whose utilisation method changes. The paper presents the results of calculations devoted to determining a safe distance between public buildings and LPG filling station facilities, using selected analytical models. The analyses were carried out for the LPG gas system commonly used in petrol stations, consisting of two gas storage tanks of 4.85 m³ capacity each, and a dispenser. It is legitimate to eliminate the obligation to observe the 60 m distance between LPG filling stations and public buildings and the mandatory distance of 60 m between liquefied gas dispensers and public buildings is not justified in light of the implemented requirements to use various protections at self-service liquefied gas filling stands.

Forensic analysis on bursting accident of buffer tank in liquefied natural gas bus

In December 2019, a buffer tank burst accident occurred in the maintenance of liquefied natural gas (LNG) bus in China. Failure analysis revealed the bus-mounted buffer tank had been subjected to an excessive internal pressurization, although the tank material met the specifications for engineering practice. The physical evidence related to the failed tank showed that a chemical explosion was impossible. As water was used to pouring the frozen pipeline prior to the accident, according to the consequences observed, the rapid phase transition (RPT) explosion of the residual LNG due to external heat from water was regarded as the main causation of incident. The explosion energy was inversely estimated by the TNT equivalent method, and the rapid expansion of natural gas produced excessive pressure, thus causing the buffer tank to explode.

Ecological consequences of space rocket accidents in Kazakhstan between 1999 and 2018

In this paper, we briefly described the ecological consequences of six space rocket accidents launched from the Baikonur Cosmodrome between 1999 and 2018 and focused on an assessment of efficiency of soil remediation following the accidental crash of launch vehicle Proton-M on July 2, 2013, which resulted in the severest environmental impact in the modern Russian space industry. On the day after the accident, the content of carcinogenic unsymmetrical dimethylhydrazine and nitrosodimethylamine, as well as nitrate in soils of the crash site exceeded their maximal permissible concentrations by 8900, 6100 and 85 times, respectively. Mitigation measures included soil detoxication by a solution of 10% H₂O₂ and 1% iron complexonate, soil excavation and ploughing. Two years later (in April 2015), both unsymmetrical dimethylhydrazine and nitrosodimethylamine concentrations were below 0.05 mg/kg and nitrate concentration did not exceed 3.9 g/kg. As compared to background sites, soils of the crash site had significantly (P-value<0.05) lower values of pH and the content of total organic carbon, basicity from soda and carbonates and higher total nitrogen and soluble salt contents. Soil microbial communities were the most vulnerable component of the disturbed arid ecosystems, as their suppressed condition was indicated by a low biochemical oxygen demand and a very low cellulase activity.

A thermodynamic model for predicting transient pressure evolution in response to venting and vaporization of liquefied gas under sudden release

Liquefied gases in energy supply chain suffer the risks of disastrous accidents (e.g. boiling liquid expanding vapor explosion) normally resulted from a sudden release. The boiling response and its associated pressure transient under sudden release determine the severity of the accident, and are crucial for assessing the consequences of the sudden release. For predicting the pressure transient, a thermodynamic model of the liquefied gas under sudden release is presented in this paper. A three-stage modelling approach is proposed to describe the entire thermodynamic process after sudden release according to the venting and boiling behaviors of liquefied gas. A set of differential-algebraic equations are established based on mass and energy conservation for predicting the transient thermodynamic parameters. Comparisons of model predictions with experimental data show a consistent trend in pressure-time histories, with relative deviations of average pressures less than 5.78 %. The results show that the minimum pressure point has a time delay compared to the boiling inception point. The increase of release pressure and the decrease of vessel scale will strengthen the pressure rebound, and the increase of vent area will lead to higher depressurization and re-pressurization rate.

Suppression effects of micro-fin surface on the explosive boiling of liquefied gas under rapid depressurization

The boiling liquid expanding vapor explosion (BLEVE) is a most severe hazard in liquefied gas storage and transportation, and its prevention depends on the suppression of the explosive boiling during tank depressurization. This paper proposes an idea of using micro-fin type surface to suppress the explosive boiling, and experimentally investigates the suppression mechanisms and quantitative effects on the explosive boiling. In the experiments, the bubble behaviors on a micro-fin and a smooth surface are observed for phenomenal analysis, and the explosive boiling consequences of the two surfaces are measured for quantitative evaluation. The results show that, the micro-fin surface brings forward the nucleation onset and reduces the boiling region, resulting in a weakened explosive boiling process. Among release pressures of 200 kPa-500 kPa and vent areas of 1.8 cm²-5.3 cm², the adopted micro-fin surface reduces the boiling-induced pressure rise and the released energy by up to 24.5% and 35.6%, respectively.

Traits and causes of environmental loss-related chemical accidents in China based on co-word analysis

Chemical accidents are major causes of environmental losses and have been debated due to the potential threat to human beings and environment. Compared with the single statistical analysis, co-word analysis of chemical accidents illustrates significant traits at various levels and presents data into a visual network. This study utilizes a co-word analysis of the keywords extracted from the Web crawling texts of environmental loss-related chemical accidents and uses the Pearson's correlation coefficient to examine the internal attributes. To visualize the keywords of the accidents, this study carries out a multidimensional scaling analysis applying PROXSCAL and centrality identification. The research results show that an enormous environmental cost is exacted, especially given the expected environmental loss-related chemical accidents with geographical features. Meanwhile, each event often brings more than one environmental impact. Large number of chemical substances are released in the form of solid, liquid, and gas, leading to serious results. Eight clusters that represent the traits of these accidents are formed, including "leakage," "poisoning," "explosion," "pipeline crack," "river pollution," "dust pollution," "emission," and "industrial effluent." "Explosion" and "gas" possess a strong correlation with "poisoning," located at the center of visualization map.

Experimental research of heat-mass coupling response of liquid storage tanks

In order to study the coupling response process of the liquid tank under the external thermal attack, experiments were carried out on a vertical cylindrical storage tank by electric heating. The response processes of the tank pressure, the medium temperatures, and the wet and dry tank wall temperatures were monitored in the experiments. The coupling responding process between the evolving characters of the medium temperature and the tank wall temperature, as well as the resulting rising features of the tank pressure were analyzed comprehensively. The results indicated that, on the one side the heat transfers process across and through the tank wall were influenced obviously by the thermal-flow fields of the two phase mediums which differ a lot in the thermal physical properties. On the other side, affected by the temperature rise in the wall, the vapor medium became thermal stratified and overheated with respect to the tank pressure, and the flow regime in the liquid medium would transform from causing stratification to promoting de-stratification affected by the wall boiling phenomenon.