Liquid Hydrogen Spills on Water—Risk and Consequences of Rapid Phase Transition

Liquid hydrogen (LH2) spills share many of the characteristics of liquefied natural gas (LNG) spills. LNG spills on water sometimes result in localized vapor explosions known as rapid phase transitions (RPTs), and are a concern in the LNG industry. LH2 RPT is not well understood, and its relevance to hydrogen safety is to be determined. Based on established theory from LNG research, we present a theoretical assessment of an accidental spill of a cryogen on water, including models for pool spreading, RPT triggering, and consequence quantification. The triggering model is built upon film-boiling theory, and predicts that the mechanism for RPT is a collapse of the gas film separating the two liquids (cryogen and water). The consequence model is based on thermodynamical analysis of the physical processes following a film-boiling collapse, and is able to predict peak pressure and energy yield. The models are applied both to LNG and LH2, and the results reveal that (i) an LNG pool will be larger than an LH2 pool given similar sized constant rate spills, (ii) triggering of an LH2 RPT event as a consequence of a spill on water is very unlikely or even impossible, and (iii) the consequences of a hypothetical LH2 RPT are small compared to LNG RPT. Hence, we conclude that LH2 RPT seems to be an issue of only minor concern.

Heat Transfer Considerations on the Spontaneous Triggering of Vapor Explosions—A Review

Vapor explosions have been investigated both theoretically and experimentally for several decades, focusing either on the vapor film, or on mechanical aspects. Where the main interest for industry lies in the safety risks of such an event, fundamental research is focusing on all partial processes that occur during a vapor explosion. In this paper, vapor explosions are discussed from a heat transfer point of view. Generally accepted knowledge of heat transfer between hot surfaces and liquids is compared to early investigations regarding the origin of vapor explosions. Both steady state and transient models are discussed. The review of available literature suggests that vapor explosions trigger spontaneously by the collapse of the boiling film. Better understanding of the fundamental aspects of vapor explosions might give rise to future ideas on how to avoid them.

Research on Safety Spacing of Chemical Storage Tanks Based on Accident Consequence and Risk Analysis

The placement of chemical storage tanks is an important topic in industrial safety, and its placement method is based on the study of the safety spacing of storage tanks. This paper takes LPG and LNG storage tanks as examples. It uses vapor cloud explosions, pool fires, pressure vessel explosions, boiling liquid expansion vapor explosions and other fire and explosion accident consequences models and risk probability analysis methods to analyze. It is proved that the transfer of storage tanks from ground to underground can significantly reduce the scope of impact of explosion accidents, thereby increasing the utilization rate of industrial land.

Model Analisis Risiko Bencana Transportasi Bahan Beracun dan Berbahaya Industri di Kabupaten Serang, Provinsi Banten

ABSTRACTPulo Ampel Industrial Zone in Serang Regency is an industrial zone with a high level of threat from a technological hazard. One possible route this threat can be manifested is in the form of explosion potential from the storage and transport tanks of toxic and dangerous materials e.g. Ethylene and Butadiene gases. Within the framework of disaster risk reduction, disaster risk analysis is carried out which includes the analysis of threats and vulnerabilities along the path of transport of these hazardous materials. To determine the level of explosion hazard, due to the occurrence of transportation accidents, modeling using ALOHA® (Areal Locations of Hazardous Atmospheres) software, which was developed by the United States Environmental Protection Agency (US EPA), was carried out. The model used in this study was the BLEVEs (Boiling Liquid Expanding Vapor Explosions) scenario during gas transportation using ISO Tank, which represents the worse possible scenario. Meanwhile, disaster vulnerability analysis is calculated based on social vulnerability aspect which includes population density and vulnerable group parameters by utilizing the scoring method in accordance to Head of BNPB Decree No.2 of 2012. Based on the hazard and vulnerability level, disaster risk maps are obtained along the Ethylene and Butadiene transport lines covering the information related to the area of the explosion which intersected with population settlement in Serang Regency, Banten Province.Keywords: risk reduction, trasportation, hazardous materials, vulnerabilities, explotionABSTRAKZona Industri Pulo Ampel di Kabupaten Serang merupakan zona industri dengan ancaman bencana kegagalan teknologi yang relatif tinggi. Ancaman bahaya yang dapat ditimbulkan diantaranya berupa potensi ledakan dari tangki-tangki penyimpanan maupun tangki transportasi bahan berbahaya dan beracun (B3) terutama gas Etilena maupun Butadiena. Dalam rangka pengurangan risiko bencana, maka dilakukanlah analisis risiko bencana terhadap tangki transportasi B3 yang meliputi analisis ancaman dan kerentanan di sepanjang jalur transportasi B3 tersebut. Untuk menentukan salah satu tingkat bahaya yang berupa ledakan akibat kecelakaan transportasi gas dilakukanlah pemodelan dengan menggunakan perangkat lunak modeling ALOHA® (Areal Locations Of Hazardous Atmospheres) yang dikembangkan oleh United States Environmental Protection Agency (US EPA). Model yang digunakan di dalam kajian ini menggunakan skenario ledakan terburuk berupa skenario BLEVEs (Boiling Liquid Expanding Vapor Explosions) pada saat transportasi gas menggunakan ISO Tank. Sementara analisis kerentanan bencana dihitung berdasarkan aspek kerentanan sosial yang meliputi parameter kepadatan penduduk dan kelompok rentan dengan menggunakan metode skoring sesuai Perka BNPB No. 2 Tahun 2012. Berdasarkan tingkat bahaya dan kerentanan tersebut diperolehlah peta risiko bencana di sepanjang jalur transportasi gas Etilena dan Butadiena yang meliputi informasi terkait luas area permukiman penduduk terdampak ledakan di Kabupaten Serang, Provinsi Banten.Kata kunci: pengurangan risiko, transportasi, bahan beracun dan berbahaya, kerentanan, ledakan

Intensification of Chemically Assisted Melt–Water Explosive Interactions

This paper investigates avenues for controlled initiation and augmentation of the mechanical and thermal energetic output of shock-triggered vapor explosions (VEs) with Al–GaInSn alloys; furthermore, enabling a means for impulsive hydrogen gas generation within milliseconds. Using a submerged electronic bridgewire detonator or rifle primer caps as the shock trigger for VE initiation, experiments were conducted with 10 g melt drops at initial temperature between 930 K and 1100 K, aluminum mass contents between 0.3 wt.% and 20 wt.%, and water temperatures between 293 K and 313 K. It was found that combined thermal–chemical Al–GaInSn–H2O explosive interactions can readily be controllably induced via shocks and are of greater intensity than the pure (spontaneous) thermally driven explosions observed with unalloyed Sn and GaInSn. Shock pressures up to 5 MPa were recorded about 10 cm from the explosion zone; a factor of 5 higher than the ∼1 MPa over pressures generated from spontaneous GaInSn–H2O explosions reported in our previous study. Al–GaInSn–H2O explosive interactions also exhibited rapid enhancements to the “impulse” H2 production rate. Hydrogen/vapor bubble volumes up to 460 ml were observed approximately 4 ms after the explosion, equating to a mechanical work and instantaneous power output of 47 J and 11.75 kW, respectively. In comparison with available, analogous, triggered-explosion studies with Al melt drops, our Al–GaInSn alloy melt at 1073 K generated up to 18 times (∼2000%) more hydrogen per gram of aluminum when compared with experiments with molten Al at a much higher melt temperature of 1243 K.