Hodnocení bezpečnostních rizik souvisejících s únikem metanu z podzemních prostor

Abstract

This PhD thesis deal with evaluation of safety risks related with escaping of methane from underground space. Underground space where methane occurs can be divided to anthropogenic and nature spaces. Anthropogenic space was formed by human activity - coal mines belong to this activity and methane is released by eroding of nearing massive during mining activity. Nature underground space arise due to nature nearing processes in the past and caves, caverns, porous structures and others belong to these types of spaces. In the last decades dangerous substances can be stored there. Nature gas which is largely composed by methane, is stored by this way in the middle Europe. Methane is twice lighter than air that caused its easy process by permeable nearing surroundings in the upwards direction to the earth surface and its follow up dispersion to the atmosphere. Methane is dangerous due to its effervescence in the mixture with the air. Accidents in the past show that explosion of methane escaping from underground space is serious problem. For evaluation of these risks exist many evaluation methods but many of them are not suitable for this issue. The most suitable method appears French method called MOSAR [79][80] which has positives and negatives. Complexity and systematic belong to the positives and to the negatives belong ambitiousness and time of feasibility. For above mentioned this work is interested in tools for evaluation of safety risks related with escaping of methane from underground space and used method called MOSAR [79][80]. In this thesis two methods were formed which evaluate escaping of methane from underground space. One of the methods which was certificate by ČBÚ as methodics evaluate escaping of methane from underground space related with finished mining activity (in the text of the work denoted as low pressure escaping). Second method evaluate escaping of methane from underground space related with underground storage of gas namely up ground and underground part of technology (in the text of the work. From cited method MOSAR [79][80], both designed methods come out and even are different. Place of use of both methods is completely different. Method witch evaluate high pressure escaping is applicable in open space or in crowded zone. Method applicable for low pressure escaping is applicable only in open or half-open spaces. Other differences are for example in the type of danger, place and character of expected and unexpected accident and rate of danger.