Ing. Ján Vereš, Ph.D.
30.12.2020
Při studiu projevů nebezpečných látek při chemických haváriích, je nezbytné převést fyzikálně-chemické projevy požárů, výbuchů a toxických rozptylů na informaci, jaké následky mají na životy a zdraví lidí a zvířat, životní prostředí a majetek. Výsledek je pak charakterizován jako výstup hodnocení následků s výskytem řady neurčitostí. Proces modelování následků v sobě nutně zahrnuje nejistoty a neurčitost. Jakýkoli přístup k modelování, ať už jevů nebo účinku, nedokáže tyto nejistoty odstranit. Analýza nejistot vyšetřuje nejistoty ve výstupech modelu vzhledem k definovaným nejistotám ve vstupech do modelu. Vědomí těchto neurčitostí spojených s výsledky hodnocení rizika je nutné brát v úvahu při rizikově orientovaných rozhodnutích. V článku je uvedena citlivostní analýza modelů úniku v zavilosti na rychlosti větru, velikosti plochy otvoru a teplotě okolí.
30.09.2019
Oblast zabývající se procesy výbuchu je velice žádoucí z pohledu ochrany zaměstnanců před účinky výbuchu v souladu s Evropskou direktivou ATEX 137 a také ve vztahu k prevenci a minimalizaci možných škod souvisejících s účinky výbuchu na technologie v energetice. Cílem práce je analyzovat a experimentálně potvrdit vliv počátečních podmínek na výbuchové parametry směsí uhelného prachu. Dílčími cíli jsou sestavení experimentální aparatury pro měření, kalibrace přístroje certifikovanými materiály, optimalizace měřícího systému pro reálné podmínky. Příprava vzorků pro laboratorní měření. Změření výbuchových parametrů za standardních a reálných podmínek a diskuse odchylek výsledků založená na výsledcích experimentálních studií. Návrh zlepšení experimentálního zařízení. Výsledky je plánováno uplatnit v ČR přednostně na energetiku, avšak budou k dispozici i pro další průmyslové sektory.
30.09.2016
A numerical study was performed on the explosion characteristics of methanol-air mixtures; at four various initial temperatures and initial pressures. The explosion parameters of explosion pressure were calculated. The influences of initial conditions on the explosion characteristics were discussed. With the initial pressure elevated from 1.0 to 2.5 bar, the peak explosion pressure increases significantly. Post explosion species composition as a function of methanol mole fraction in the methanol-air post-explosion mixtures (15 vol. % of fuel) for P = 1.0 bar(a) and T = 298 K have been determined. These values will be used as approximate initial values for explosion experiments carried out in heated 1 m3 and 20 dm3 explosion apparatuses designed by OZM Research s.r.o. and used at Laboratory of safety fuels and technologies, Energy Research Centre, VŠB - Technical University of Ostrava.
11.01.2016
Gas mixture explosions and fires are responsible for most of the largest property loss events worldwide in the chemical and power industry. In this contribution, a theoretical analysis was performed of explosion behavior for CO/O2/N2, CO/O2/N2/H2O and CO/O2/N2/CO2 mixtures. Presented explosions based on real scenarios of accidents associated with transport and storage facilities with flammable chemicals. While explosions of pure flammable chemicals are well described in the literature, the information about explosions of toxic flammable substances is rather scarce. This work aims at studying the explosion behavior of pure mixture and of the inerted carbon monoxide-air mixtures at different initial temperatures and pressures. The results of mathematical modeling of the calculated maximum explosion pressure are presented.
11.01.2016
Renewable energies became more and more important in the last years. The production of biogas using agricultural waste and the use of wind and solar energy in combination with water electrolysis is one way to substitute natural gas. Therefore the number of syngas plants is growing very fast. On the other hand, the operation of such plants could be responsible for a significant number of accidents. The main focuses of this contribution are the explosion characteristics and hazards arising from the biogas. Primarily, these are the hazards of fire and explosion induced by flammable components of syngas. However, further hazards are the dangers of asphyxiation and poisoning by gases such as carbon monooxide. These hazards will be the aim of the following article. In order to prevent explosions when storing and handling syngas it is necessary to know the explosion limits of individual gas components and its gas mixtures in mixture with air. However, syngas from gasification unit can vary significantly in its composition. Therefore, for each gas composition the explosion limits would have to be determined. This would require a considerable amount of time and effort. Due to this fact, the explosion limits of syngas are frequently referred to only by the hydrogen fraction of the gas mixture in the safety-relevant literature. In reality as syngas consists of hydrogen, methane, carbon monoxide, carbon dioxide and further residual gases the explosion limits are generally over or underestimated.
11.01.2016
A theoretical study on maximum explosion pressure is presented. The maximum explosion pressures, computed by assuming chemical equilibrium within the explosion front are examined in comparison with the measured explosion pressures. Comparisons of the experimentally measured pressures with the calculated adiabatic pressures indicate the degree of adiabacity of the explosion. The calculated peak explosion pressures of hydrogen-air mixtures for ambient conditions are examined in comparison with the experimental values and with the calculated adiabatic explosion pressures. In the present contribution we calculated the maximum pressure for hydrogen-air mixtures in a spherical closed volume at different initial temperatures up to 200 °C. The results represents a continuation of numerous efforts by various research groups, where the key underlying problem has been the understanding of results obtained in laboratory tests for predicting the consequences of gas explosion scenarios in industry.
14.10.2015
A theoretical study on maximum explosion pressure and constant volume adiabatic flame temperature is presented. The maximum explosion pressures, computed by assuming chemical equilibrium within the explosion front are examined in comparison with the measured explosion pressures. Comparisons of the experimentally measured pressures with the calculated adiabatic pressures indicate the degree of adiabacity of the explosion. The calculated peak explosion pressures of methane-air mixtures for ambient conditions are examined in comparison with the experimental values and with the calculated adiabatic explosion pressures. The results represents a continuation of numerous efforts by various research groups, where the key underlying problem has been the understanding of results obtained in laboratory tests for predicting the consequences of gas explosion scenarios in industry.
Užitečné odkazy
Provozovatel portálu
Výzkumný ústav bezpečnosti práce, v. v. i.
Jeruzalémská 1283/9
110 00 Praha 1
Jeruzalémská 1283/9
110 00 Praha 1
Sociální sítě VÚBP
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