Nowadays, when we try to automatize all activities, there is a growing demand for energy in all forms. Increasingly we reach for new energy sources that can be problematic to store or to transport, owing to their toxicity or explosive propensity. The article examines the issues of determining danger zones occurring as a result of liquefied natural gas (LNG) release. The range of danger zones caused through LNG release depends on a multitude of factors. The basic parameter that needs to be considered is a type of the released substance as well as the manner of its release. The range of a danger zone is determined by, inter alia, the concentration of a released substance and the atmospheric conditions existing at the time when depressurization occurs. The article analyses the problem of the range of danger zones in a function of wind speed and surface roughness with a defined value of Pasquill stability for various LNG types, starting with pure methane, and ending with the so-called LNG-heavy. The difficulty of the task becomes more complicated when the analysed surface over which a depressurization incident takes place involves water. The problem deepens even further when the analysed substance possesses explosive properties. Then, apart from regular substance concentration, upper and lower flammability limit ought to be considered. Calculations were conducted with DNV-Phast software, version 7.11.
The development of new technologies, the use and transport of LNG increases the number of investments that may mutually affect their safety on account of a domino effect. It means that a breakdown caused by one of the business entities may contribute to the escalation of a problem through thermal energy emission in another entity. The energy absorbed in an adjacent technological process line may cause irreparable damage despite the security measures employed. When planning an investment of a pioneering nature, one ought to consider not only the modern technologies used in a newly designed installation, but one must also pay attention to the direct neighbourhood of other industrial plants and the planned infrastructure, e.g. for gas transport or transhipment. Such a synergistic approach guarantees the safety of undertaken activities and ensures a stable, breakdown-free operation of all the business entities located in a given area. This paper discusses the issue of mutual influence exerted by two independent entities located within a small distance of one another, i.e. salt processing plant and a vessel transporting an LNG mixture. The authors considered a situation in which a breakdown occurs in an industrial plant and in which the released energy causes damage to a tank shell of an LNG carrying vessel on an inland fairway. In the examined situation the types of risks arising from LNG tank shell damage on-board an inland vessel were defined and the dimensions of the resulting danger zones were determined in a function of concentration of individual LNG components as well as the pressure and temperature generated inside the tank. The shape of the tank was also taken into consideration, since it affects fractioning in the course of the release of the substance accumulated in it. The analysis was conducted on the basis of DNV Phast 7.11 software.
The analysis of danger zone ranges for LNG in the coastal area is an important task on account of, inter alia, the safety of human life. It is not an easy process, which is why we consider an danger situation for various weather conditions in the function of constant wind speeds and for various wind speeds in constant weather stability. Pasquill weather stability scale and Beaufort scale with regard to terrain roughness were adopted for the analysis. Both scenarios were considered in the example of Q-flex type vessels in the Świnoujście terminal for two methods of LNG release, i.e. related to a sudden explosion and slow release caused by a leak. The analysis was conducted and considered for the values in the top and bottom flammability limit. Modelling of the danger zone range was analysed with DNV PHAST software, version 7.11. In the process of comparison of the situation related to the risk of explosion in the function of various weather stabilities according to Pasquill scale and constant wind speeds, the values of 1.5 m/s and 5 m/s were adopted, corresponding to 1 and 3 wind force on the Beaufort scale. Those speeds correspond to the water conditions featuring tiny ripples and small waves, the crests of which start to break. The adopted weather stabilities analysed for wind speed equal to 1.5 m/s are A, B, D. A-type stability signifies the least stable atmospheric conditions, and D-type means neutral conditions. In turn, for the wind speed of 5 m/s B, D and F parameters in Pasquill scale were selected. Furthermore, ranges for variable wind speed values were analysed for the selected Pasquill stability.