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V okviru diplomskega dela bo predstavljena nezgoda v podjetju Isotec, ki se je zgodila leta 2003 v Ohiu, Združenih državah Amerike. Gre za nezgodni dogodek povišanega tlaka in posledično razpoka procesne enote dušikovega oksida, strupenega, brezbarvnega plina z močnim vonjem, ki je uničil kolono za podzemno destilacijo, pri čemer je bil ranjen en delavec. Diplomsko delo povzema ugotovitve preiskovalne komisije CSB nastalega nezgodnega dogodka povišanega tlaka ter predstavi smernice za preprečevanje takšnih nezgod. Posvetila sem se Tlačni direktivi 2014/68/EU ter HAZOP analizi. Da bi čim bolj zmanjšali nezgode v industrijah so strokovnjaki razvili metode s pomočjo katerih sistematično in organizirano pridemo do rešitev na podlagi odstopanj ali okvar. S pomočjo skice, priložene v poročilu CSB in metode HAZOP sem v eksperimentalnem delu analizirala vzroke in posledice odpovedi posameznih komponent. Metoda HAZOP je namenjena iskanju in preprečevanju težav že v začetnih fazah. To je tehnika za strukturirano in sistematično preučevanje načrtovanega ali obstoječega sistema, postopka in procesa, ki se uporablja za ugotavljanje vseh odstopanj od običajnega načina obratovanja sistema, njihovih vzrokov ter vseh povezanih nevarnosti in težav. Za izvedbo metode moramo najprej razdeliti sistem, proces ali postopek na manjše elemente (dele), določiti ustrezne parametre in z njimi v kombinaciji uporabiti vodilne besede. Nato se določijo vzroki za vsako ključno besedo in parameter, ter posledice oziroma težave. Določiti je potrebno ukrepe (kaj, kdo, kdaj). Zelo pomembno je, da se razprava in ugotovitve beležijo in da se postopek ponavlja za vsak element sistema. Na podlagi članka sem ugotovila, da je raziskava nezgode pokazala kar nekaj napak na področju zagotavljanja varnosti v podjetju. V diplomskem delu bom predstavila dva pristopa za identifikacijo nevarnih dogodkov: uporabo vprašalnikov in metodo HAZOP. Izvedla sem obe analizi in na podlagi rezultatov zaključila, da je za takšen sistem destilacije potrebno dodati dodatne varnostne elemente ter procese. Potrebna je vezava merilnika tlaka izolacijskega plašča kolone na varnostni izklop poteka destilacije, vgradnja varnostnega ventila na izolacijski plašč destilacijske kolone, vgradnja merilnika temperature in tlaka hladilnega medija izmenjevalnikov toplote in vgradnja varnostne ploščice na destilacijsko kolono in reaktor. The accident at the Isotec Company, which occurred in 2003 in Ohio, United States of America, will be presented as part of the thesis. It is an accidental event of elevated pressure and subsequent rupture of a process unit of nitrous oxide, a toxic, colorless gas with a strong odor, which destroyed an underground distillation column, injuring one worker. The thesis summarizes the findings of the CSB commission of inquiry into the resulting high pressure accident and presents guidelines for the prevention of such accidents. I focused on the Pressure Directive 2014/68/EU and the HAZOP analysis. In order to reduce accidents in industries as much as possible experts have developed different methods. With help from these methods, systematic and organized solutions can be found based on deviations or defects. With the help of the sketch attached in the CSB repost and the HAZOP method, I analyzed the causes and consequences of individual component failures in the experimental part. The HAZOP method is aimed at finding and preventing problems already in the initial stages. It is a technique for the structured and systematic study of a planned or existing system, procedure and process, used to identify any deviations from the normal operation of the system, their causes and any associated hazards and problems. To implement this method, we must first divide the system, process or procedure into smaller elements (parts), determine the appropriate parameters, and use guiding words in combination with them. Afterwards, the causes for each keyword and parameter, as well as the consequences or problems, are determined. It is necessary to define measures (what, who, when). It is very important that the discussion and findings are recorded and the process is repeated for each element of the system. Based on the article, I found that the investigation of the accident showed quite a few errors in safety management of the company. In my thesis, I will present two approaches for identification of dangerous events: the use of questionnaires and the HAZOP method. I preformed both analyses, and based on the results concluded, that it is imperative to add additional safety elements and processes for such a distillation system. It is necessary to connect the column insulation jacket pressure gauge to the safety shutdown of the distillation process, install a safety valve on the distillation column insulation jacket, install a temperature and pressure gauge of the cooling medium of the heat exchangers, and install a safety plate on the distillation column and reactor. |
