Simulacija posledic nenadzorovanega sproščanja amonijaka s programom ALOHA

Kne Gartner, Urša (author), Schnabl, Simon (mentor)

Dnevno se prevažajo velike količine nevarnih snovi, ki imajo v primeru, da pride do nezgode lahko hude posledice za ljudi in okolje. Ena izmed nevarnih kemikalij, ki se prevaža je tudi amonijak. Amonijak je dražilna kemikalija, ki lahko resno vpliva na ljudi ob preveliki izpostavljenosti in ima resne posledice za okolje. Izpostavljenost visokim koncentracijam lahko pripelje do akutne zastrupitve in posledično celo smrti. V teoretičnem delu magistrskega dela sem raziskala lastnosti in škodljive učinke amonijaka na ljudi in okolje ter podrobneje preučila tveganja in vzroke za nezgode pri prevozu nevarnih snovi. Raziskala sem tudi prednosti in slabosti računalniškega programa ALOHA. Namen magistrske naloge je bil simulirati posledice nenadzorovanega sproščanja amonijaka iz cisterne z računalniškim programom ALOHA. Program nam glede na vhodne podatke izriše različna območja, kot so območja nevarnih koncentracij, območja vnetljivosti in območja toplotnega sevanja. Predpostavila sem, da je do nezgode prišlo v Škofji Loki, na regionalni cesti Škofja Loka – Železniki, kjer je velika zgoščenost prebivalstva. V bližini se nahajajo šole, vrtci, športna dvorana, dom starejših občanov in številni stanovanjski objekti. Poudarek je bil na ugotavljanju, kako vplivajo različni meteorološki parametri na posledice izpusta amonijaka in kakšen del okoliških objektov in naselij zavzamejo območja izpostavljenosti. Simulacije sem izvedla za tri različne scenarije. Prvi scenarij je predstavljal izpust amonijaka iz cisterne, pri čemer je ta izhlapeval, a se ni vnel. Pri njem smo analizirali območja nevarnih koncentracij in območja vnetljivosti. Drugi scenarij je bil pojav gorečega curka pri katerem smo obravnavali območja toplotnega sevanja. Pri tretjem scenariju sem prav tako obravnavala območja toplotnega sevanja, vendar za eksplozijo BLEVE. Vse omenjene scenarije sem simulirala v štirih letnih časih. Poleg tega me je še zanimalo, kakšen vpliv imajo različne hitrosti vetra na območja nevarnih koncentracij in na območje vnetljivosti. S tem namenom sem prvi scenarij, kjer je kemikalija izhlapevala, a se ni vnela, analizirala v zimskem letnem času za različne hitrosti vetra. Glede na dobljene rezultate simulacij sem ugotovila, da imajo meteorološki parametri velik vpliv na velikost območij nevarnih koncentracij in območij vnetljivosti, nimajo pa velikega vpliva na območja toplotnega sevanja. Ugotovila sem, da je hitrost vetra pomemben meteorološki parameter, ki vpliva na posledice izpusta amonijaka, zlasti na območja vnetljivosti.

• Language: Slovenian
• Keywords: amonijak, ALOHA, izpust kemikalije, območje vpliva
• Work type: Master's thesis/paper
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-161063
• Publication date in RUL: 06.09.2024

Secondary language

• Language: English
• Title: Simulation of the consequences of uncontrolled ammonia release with the ALOHA program

Abstract

Large quantities of dangerous substances are transported daily, which in the event of an accident can have serious consequences for people and the environment. Ammonia is one of the dangerous chemicals being transported. Ammonia is an irritant chemical that can seriously affect humans if over-exposed and has serious consequences for the environment. Exposure to high concentrations can lead to acute poisoning and even death. In the theoretical part of my master's thesis, I investigated the properties and harmful effects of ammonia on people and the environment, and studied in more detail the risks and causes of accidents in the transport of dangerous substances. I also researched the pros and cons of the ALOHA computer program. The purpose of the master's thesis was to simulate the consequences of an uncontrolled release of ammonia from a tank using the computer program ALOHA. Depending on the input data, the program draws different areas for us, such as areas of dangerous concentrations, areas of flammability and areas of thermal radiation. I assumed that the accident happened in Škofja Loka, on the regional road Škofja Loka - Železniki, where there is a high concentration of population. Nearby are schools, kindergartens, a sports hall, a home for senior citizens and many residential buildings. The focus was on determining how different meteorological parameters affect the consequences of ammonia release and what part of the surrounding buildings and settlements are occupied by the exposure areas. I performed simulations for three different scenarios. The first scenario represented the release of ammonia from the tank, where it evaporated, but did not ignite, and we analyzed the areas of dangerous concentrations and areas of flammability. The second scenario was the occurrence of a Jet fire in which we considered areas of thermal radiation. In the third scenario, I also considered thermal radiation zones, but for the BLEVE explosion. I simulated all the mentioned scenarios in four seasons. In addition, I was also interested in what effect different wind speeds have on areas of dangerous concentrations and on the area of flammability. With this aim in mind, I analyzed the first scenario where the chemical evaporated but did not catch fire in the winter season for different wind speeds. Based on the results of the simulations, I found that the meteorological parameters have a great influence on the size of the areas of dangerous concentrations and areas of flammability, but they do not have a great influence on the areas of thermal radiation. I found that wind speed is an important meteorological parameter that affects the consequences of ammonia release, especially in areas of flammability.

• Keywords: ammonia, ALOHA, chemical release, threat zone