Risk assessment of probable hazards, is one of the major stages for upgrading safety level of existent process or a process in design phase. Risk assessment is a method for deciding is safety upgrading of a unit economical or not. In developed countries, risk assessment is essential for process unit. In this paper in order to introduce risk assessment, its implementation steps such as hazard identification, consequence modeling and risk calculation method such as risk matrix and F-N curve have been discussed. Consequence modeling of hazards such as fire, explosion and toxic releases, which may occur due to human error or failure of equipment, is an important stage of risk assessment that nowadays carried out by computer softwares. At last, a case study of risk assessment has been studied for ammonia Storage tanks of a petrochemical complex by using software PHAST for consequence modeling.

In this work, a series of three-dimensional unsteady numerical simulations are performed to study the stability and interface dynamics of a thermocline-based lab-scale single tank Thermal Energy Storage system (TES). The stability of thermocline is analysed by introducing relatively cold fluid for a short period at the inlet of the TES. Numerical simulations are performed for three inlet flow disturbances (weak, medium and strong) and three stratification levels (sharp, moderate and large). The fluid injected at the inlet rolls-up and interacts with the thermocline which causes spatio-temporal disruption of the stable stratification inside the TES. It was found that the three-dimensional simulations bear some resemblance to the two-dimensional case but also show crucial differences. The propagation of the injected cold fluid and the subsequent interaction with the thermocline are analysed. A wide gamut of flow structures is identified inside the TES depending on the degree of stratification and level of disturbance. Finally, the oscillatory nature of interface and associated mixing mechanism are addressed. The simulation indicates that the oscillations at the interface are through the successive generation of countersign vorticity which retards/suppresses the propagation of the vortex ring. In the case of large interface, internal waves are generated by the periodic array of vortices which generates a standing wave pattern near the Brunt-Va ̈isa ̈la ̈ frequency‎.

The behavior of Storage tanks' analysis in seismic areas is of major importance because of the strategic nature of these works. The steel cylindrical tanks are the most susceptible to damage due to dynamic buckling during earthquakes. In this study, three criteria are used to estimate the critical peak ground acceleration caused the tank instability. The liquid inside the tank was modeled using specific Ansys's finite elements and fluid-structure interaction. The calculation includes modal and time history analysis, including material and geometric non-linearity. The result values are compared with standard code previsions as well as the results of previous numerical research, and show the need to improve code provisions.

Earthquake response of liquid Storage tanks isolated by the sliding systems is investigated under bi-directional earthquake motion (i.e. two horizontal components). The frictional force of sliding systems is modeled by two ways referred as conventional and hysteretic model. The continuous liquid mass is lumped as convective mass, impulsive mass and rigid mass. The Corresponding stiffnesses associated with these lumped masses are worked out depending upon the properties of the tank wall and liquid mass. The governing equations of motion of the tank with sliding system are derived and solved by Newmark’s step-by-step method with iterations. The frictional forces mobilized at the interface of the sliding system are assumed to be velocity independent and their interaction in two horizontal directions is duly considered. For comparative study the earthquake response of isolated liquid Storage tank obtained by conventional model is compared with corresponding response obtained by hysteretic model. In order to measure the effectiveness of isolation system the earthquake response of isolated tank is also compared with non-isolated tank. A parametric study is also conducted to study the effects of aspect ratio of the tank on the effectiveness of seismic isolation of the liquid Storage tanks. It is found that the sliding systems are quite effective in reducing the earthquake response of liquid Storage tanks. In addition, the same earthquake response of liquid Storage tanks is predicted by conventional and hysteretic model of the sliding system.

According to the strategic geographic position of IRAN with the probability of terrorist threats and air strikes, and also the important crucial role of the tanks, their construction by taking passive defense measures and considerations is necessary. Because of few researches on the vulnerability of tanks against the loads due to explosion, investigate the importance of this type of structures against blast loads is increasing. In present study a hypaethral cylindrical concrete tank, exposed to air blasting by one cubic explosive TNT with weight of 352.08 kg has been modeled. The tank is modeled in four situations such as: empty state, 1/4, 1/2 and 3/4 of body height full of liquid. The results of simulation showed that damages of compressive and tensile in the empty tank are more critical than other modes, and the manner of hypaethral concrete tanks against explosive loads is different from their manner against seismic loads caused by the earthquake. It was also shown that the conwep method has considerate only the effects of the explosion and at least 25% reduction achieved in compressive damage compared with the results of the AUTODYN. The results of this study can be used in retrofitting and safe design of fluids Storage tanks to resistance against the blast loads.

Spherical Storage tanks are widely used for various types of liquids, including hazardous contents, thus requiring suitable andcareful design for seismic actions. On this topic, a significant case study is described in this paper, dealing with the dynamicanalysis of a spherical Storage tank containing butane. The analyses are based on a detailed finite element (FE) model; moreover, a simplified single-degree-of-freedom idealization is also set up and used for verification of the FE results. Particularattention is paid to the influence of sloshing effects and of the soil– structure interaction for which no special provisionsare contained in technical codes for this reference case. Sloshing effects are investigated according to the current literaturestate of the art. An efficient methodology based on an “ impulsive– convective” decomposition of the container-fluid motionis adopted for the calculation of the seismic force. With regard to the second point, considering that the tank is founded onpiles, soil– structure interaction is taken into account by computing the dynamic impedances. Comparison between seismicaction effects, obtained with and without consideration of sloshing and soil– structure interaction, shows a rather importantinfluence of these parameters on the final results. Sloshing effects and soil– structure interaction can produce, for the caseat hand, beneficial effects. For soil– structure interaction, this depends on the increase of the fundamental period and of theeffective damping of the overall system, which leads to reduced design spectral values.

Liquid Storage tanks are crucial in various applications, such as in industrial processes and water supply systems. It's important to understand how these tanks behave during seismic events to ensure their structural safety. This study examines the force applied to the roof of tanks when the freeboard is insufficient. To conduct the analyses, the Box-Behnken design of the experiment method was used in the study's design. tanks were modeled using the finite element method combined with smooth particle hydrodynamics. The interaction of the stored fluid with the roof of the tank was assessed using the penalty technique and the soft constraint algorithm. The analysis results showed that the combination of two parameters, the tank length and seismic stimulation, had the most significant impact. However, the fluid height was deemed a non-influential parameter when there was not enough freeboard. Additionally, the results showed that the intensity acceleration spectrum accurately reflects the impact of frequency content on roofed tanks.

Rasht is one of the richest cities in rainfall in Iran, and because of collecting rain from the roof of the buildings a considerable amount of water can be stored, then designing and implementing of rainwater collection systems in Rasht can collect and save a significant amount of rainwater for usages like: green-space irrigation or Non-drinkable usages as whole. The catchment bank (rainwater Storage bank) is the most important and expensive component of Rainwater Harvesting System (RWH) implementation on the roof of residential buildings. The reliability of these Storage banks was estimated between 100% and 82% in three years of wetness, drought and normal index. The demand amount of this research is considered equal to the water needed for the irrigation of the cultivated grass in the green space of each building in the hot seasons. Then, we have estimated the optimum volume of Storage bank using mixed integer linear programming method in LINGO. 17 software for each of the buildings considering the expected reliability coefficient of the Storage banks (70, 80 and 90%). These volumes are between 1. 18 and 13. 49 cubic meters in three years of wetness, drought and normal index with different reliabilities. Finally, we have estimated the Storage bank volume of each demand for one of the roofs in different demands and the results were calculated between 0. 55 and 5. 26 cubic meters.

This paper introduces an improved isolation system for aboveground Storage tanks (ASTs). In this system, the tank shell is supported by a ring of vertical isolation systems (VIS) that dampen the rocking motion of the tank shell caused by dynamic loads. On the other hand, the forces in the vertical direction caused by the overturning moment are isolated as an alternative to the common horizontal system used for shear base isolation of ASTs. The effects of the proposed vertical isolation system on the seismic responses of the contained liquid are examined using various tank dimensions and earthquake ground motions. The finite element model (taking into account fluid-structure interaction effects) is used to simulate the contained liquid, as well as the tank shell. The results indicate that the new system could efficiently reduce the main seismic design parameters of the tanks, including base shear, overturning moment, and seismic stress in the tank shell. The sloshing wave height, however, is not significantly affected.