@misc{HajhaririEberweinPerroneetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Perrone, Luca Pakj and Cozzani, Valerio and Otremba, Frank and Seidlitz, Holger}, title = {Study the impact of spacer at thermal degradation process of MLI-based insulation in fire condition}, series = {Journal of Loss Prevention in the Process Industries}, volume = {92}, journal = {Journal of Loss Prevention in the Process Industries}, publisher = {Elsevier BV}, issn = {0950-4230}, doi = {10.1016/j.jlp.2024.105461}, pages = {240 -- 248}, abstract = {To reduce CO2 emissions, energy carriers such as hydrogen are considered to be a solution. Consumption of hydrogen as a fuel meets several limitations such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquified phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Different studies have been addressed the vulnerability of such insulation against high thermal loads e.g., in an accident engaging fire. Some of research works have highlighted the importance of considering the MLI thermal degradation focusing on its reflective layer. However, limited number of studies addressed the thermal degradation of spacer material and its effect on the overall heat flux. In this study, through systematic experimental measurements, the effect of thermal loads on glass fleece, glass paper as well as polyester spacers are investigated. The results are reported in various temperature and heat flux profiles. Interpreting the temperature profiles revealed that, as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Each individual spacer contributes to mitigating the radiative energy received by the measurement plate. Stacks of 20-50 spacers (this is the number of layers in commercial MLI systems applied for liquid hydrogen applications) can potentially reduce the thermal radiation by 1-2 orders of magnitude. An empirical correlation to predict a heat flux attenuation factor is proposed, which is useful for further numerical and analytical studies in the temperature range from ambient to 300 °C.}, language = {en} } @misc{HajhaririEberweinCampleseetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Camplese, Davide and Scarponi, Giordano Emrys and Cozzani, Valerio and Otremba, Frank and Seidlitz, Holger}, title = {Non-Combustible MLI Based Insulation Behavior Under Fire Condition - Experimental and Numerical Investigation}, series = {Process Safety and Environmental Protection}, volume = {193}, journal = {Process Safety and Environmental Protection}, publisher = {Elsevier BV}, issn = {0957-5820}, doi = {10.1016/j.psep.2024.11.037}, pages = {403 -- 420}, abstract = {The number of applications that demand zero-emission energy carriers, such as liquified hydrogen (LH2), is increasing worldwide. LH2 is typically transported or stored under cryogenic conditions. Storage in such conditions requires super thermal insulations which maintain very low boil-off for a prolonged time. Multi-Layer insulation (MLI) finds widespread use in cryogenic applications, designed to effectively restrict heat inleak towards cryogenic fluids. However, recent studies evidenced that exposure to high heat fluxes, such as in the event of a fire accident, can cause the thermal degradation of the insulation material, resulting in the severe collapse of its heat resistance performance. Therefore, the risk of rapid tank pressurization and its connection to the risk of BLEVE may be possible. This study proposes a numerical model to assess the performances of aluminum-based MLI materials under fire conditions. The model offers insights into the total heat transfer rate through the insulation, serving as an indicator of the deterioration's impact on overall heat transfer. The proposed numerical model is validated against experimental data obtained by a High-Temperature Thermal Vacuum Chamber test facility that reproduces fire exposure conditions. The experiments conducted in this study underscore the emergence of pressure build-up within the insulation system, which contributes to increased gas conduction. Furthermore, it demonstrates that the spacer material is not entirely damaged under simulated fire conditions. The numerical calculation also underscores the significance of the modifications in material surface emissivity due to the deterioration process. The innovative approach proposed in this study thus paves the way for the development of improved tools aiming at the stationary and mobile cryogenic tanks behavior (e.g., LNG, LOX, LN2, and LH2) in fire accident scenarios. The model developed may, in perspective, be integrated into both CFD and lumped models for the calculation of the time to failure of cryogenic equipment under external fires. Therefore, this study offers valuable insights to improve the safety of processes and equipment for the storage of cryogenic fluids, thereby supporting emergency response planning in case of fire accidents.}, language = {en} } @misc{SeidlitzHajhaririEberweinetal., author = {Seidlitz, Holger and Hajhariri, Aliasghar and Eberwein, Robert and Perrone, Luca Pakj and Cozzani, Valerio and Otremba, Frank}, title = {Study the Impact of Spacer at Thermal Degradation Process of MLI-based Insulation in Fire Condition}, series = {Proceedings of the 15th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions}, journal = {Proceedings of the 15th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions}, editor = {Di Benedetto, Almerinda and Portarapillo, Maria}, address = {Napoli, Italy}, doi = {10.5281/zenodo.12621001}, pages = {744 -- 755}, abstract = {To reduce carbon dioxide emissions, energy carries such as hydrogen consider to be a solution. Consumption of hydrogen as a fuel meets several restrictions such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquid phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Some studies have been revealed vulnerability of this type of insulation against high heat flux, for instance a fire accident. Some investigations have been depicted the importance of consideration of the MLI thermal degradation in terms of its reflective layer. However, limited number of studies have been focused on the thermal degradation of spacer material and its effect on the overall heat flux. In this study, through systematic experimental measurements, the effect of thermal loads on glass fleece, glass paper as well as polyester spacers are investigated. The results are reported in various temperature and heat flux profiles. Interpreting the temperature profiles revealed as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Moreover, the contribution of each individual spacer in all cases regarding the experimental temperature range is assessed to be around 8\%. This value may increase to around 50\% for glass paper and polyester spacers, and to around 25\% for glass fleece spacers as the number of spacer layers increases up to six layers. To utilize the outcomes of the experiment later and integrate the results into numerical and CFD simulations, a model is proposed for the mentioned experimental temperature range up to 300°C to predict a heat flux attenuation factor. The model proposes a fitting factor that can reproduce the least square fitted line to the experimental data.}, language = {en} } @misc{HajhaririEberweinCampleseetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Camplese, Davide and Scarponi, Giordano Emrys and Otremba, Frank and Cozzani, Valerio and Seidlitz, Holger}, title = {A comprehensive numerical study of the behaviour of an LH2 storage tank in the event of a fire}, series = {Chemical engineering transactions}, journal = {Chemical engineering transactions}, number = {116}, publisher = {AIDIC Servizi S.r.l.}, address = {Milano}, isbn = {979-12-81206-18-2}, issn = {2283-9216}, doi = {10.3303/CET25116114}, pages = {679 -- 684}, abstract = {As the world moves towards green energy production, effective storage and transportation solutions become essential. To support this transition, energy carriers with minimal or zero environmental impact are required. Liquified hydrogen represents a promising candidate due to its emissions-neutral properties. However, its highly flammable nature necessitates adherence to strict safety codes and standards. Storing hydrogen often requires advanced super-insulation materials. To enhance the safety of cryogenic hydrogen storage tanks under extreme conditions, such as those encountered during fire accidents, it is crucial to understand the thermal behaviour of the tank. Predicting pressurization and potential failure in advance demands a robust and comprehensive model. However, still such models suffer lack of detailed heat transfer models which account for various sub-processes during an accident scenario. Hence, this study introduces a comprehensive model for the pressurization of cryogenic tanks equipped with multi-layer insulation (MLI) systemsin the event of fire, which comprises several sub-models. These sub-models account for heat transfer phenomena through the thermal insulation at nominal conditions and its thermal degradation during fire exposure, the fluid, the internal pressurization, and the performance of the pressure relief valve. This study provides valuable insights into the safety and the behaviour of hydrogen storage tanks under thermal loads.}, language = {en} } @misc{HajhaririEberweinCampleseetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Camplese, Davide and Scarponi, Giordano Emrys and Otremba, Frank and Cozzani, Valerio and Seidlitz, Holger}, title = {Repeatable testing of a cryogenic storage tank with variable insulation material in fire like conditions}, series = {Cryogenics 2025 : proceedings of the 18th IIR International Conference on Cryogenics}, volume = {2025}, journal = {Cryogenics 2025 : proceedings of the 18th IIR International Conference on Cryogenics}, publisher = {Institut International du Froid}, address = {Paris}, doi = {10.18462/iir.cryo.2025.0007}, pages = {6}, abstract = {For decarbonizing the energy industry and transport, cryogenic energy carriers have great potential. The storage takes place in tanks with thermal super-insulations, which are in application for decades, but there is only limited knowledge about its behaviour in a fire scenario. This represents a major incident that may generate extraordinary loads on the tank and its insulation system, and that eventually lead to a sudden tank failure. This paper presents a test rig called the Cryogenic High Temperature Thermal Vacuum Chamber (CHTTVC), which can be used to test typical thermal superinsulation's under cryogenic and fire-like conditions in parallel. The test method makes it possible to measure the heat flow through the thermal superinsulation over time and to investigate the degradation behaviour of the insulation within a test. In the paper results from the first tests are presented.}, language = {en} } @misc{HajhaririEberweinCampleseetal., author = {Hajhariri, Aliasghar and Eberwein, Robert and Camplese, Davide and Scarponi, Giordano Emrys and Cozzani, Valerio and Seidlitz, Holger}, title = {Cryogenic storage safety : experimental evaluation of insulation under extreme conditions}, series = {Journal of loss prevention in the process industries}, volume = {101}, journal = {Journal of loss prevention in the process industries}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {0950-4230}, doi = {10.1016/j.jlp.2026.105961}, pages = {1 -- 20}, abstract = {Hydrogen is recognized as a keystone of the global energy transition, offering a clean, high-energy-density energy carrier ideal for storage and transportation. Among various storage options, liquid hydrogen (LH2) is especially advantageous for both mobile and stationary applications. However, ensuring the safety and performance of LH2 storage systems under extreme thermal conditions, such as fire exposure, remains an engineering challenge. This study introduces an experimental framework, called the Cryogenic High-Temperature Thermal Vacuum Chamber (CHTTVC), designed to investigate the thermal-hydraulic response of vacuum-insulated cryogenic tanks under fire-like conditions. The apparatus enables evaluation of insulation performance, such as perlite and multilayer insulation (MLI), with a focus on thermal degradation, heat ingress, and vacuum stability. Results indicate that combustible MLIs undergo substantial thermal degradation, leading to heat ingress rates of up to 6.5 kW and the formation of hazardous combustion by-products. In contrast, non-combustible MLIs and bulk insulation materials restrict heat ingress to approximately 3 kW while more effectively preserving vacuum integrity. Combustible MLIs also exhibit pronounced pressure increases in the evacuated section, reaching ∼6 × 104 Pa, nearly six times higher than those observed for non-combustible counterparts. Analysis of effective emissivity further reveals an enhancement in radiative heat transfer, approximately five times, for combustible MLIs following degradation. Additionally, marked thermal stratification develops under both nominal and extreme heat loads, with temperature gradients approaching 10 °C per 100 mm during sustained thermal exposure.}, language = {en} }