Quantitative Risk Assessment of Biogas Plant – Determination of Assumptions and Estimation of Selected Top Event

Biogas plants are a specific facility from the QRA (Quantitative Risk Assessment) methodologies' point of view, especially in the case of the determination of the event frequency of accident scenarios for biogas leakage from a gas holder and subsequent initiation. QRA methodologies determine event frequencies for different types of accident events related to vessels made of steel. Gas holders installed at biogas plants are predominantly made of other materials and are often integrated with the fermenter. It is therefore a specific type of gas holder, differing from that which is commonly used in the chemical industry. In addition, long-term experience is not available for the operation of biogas plants, unlike in the chemical industry. The event frequencies listed in the QRA methodologies are not relevant for the risk assessment of biogas plants. This work is focused on setting the prerequisites for QRA of biogas storage, including for example: information on hazardous chemical substances occurring at biogas plants, their classification, and information on the construction of integrated gas holders. For the purpose of the work, a scenario was applied where the greatest damage (to life or property) is expected. This scenario is the leakage of the total volume of hazardous gas substance from the gas holder and subsequent initiation. Based on this information, a "tree" was processed for "Fault Tree Analysis" (FTA), and frequencies were estimated for each event. Thereafter, an "Event Tree Analysis" was carried out. This work follows up on a discussion by experts on the determination of scenario frequencies for biogas plants that was conducted in the past

Modelování následků úniku bioplynu z plynojemu

This paper describes modelling of consequences of biogas leakage from a gasholder on agricultural biogas station. Four scenarios were selected for the purpose of this work. A rupture of gasholders membrane and instantaneous explosion of gas cloud, blast of gas with delay, emptying of whole volume of gas (without initiation) and initiation of gas with Jet-Fire. Leakage of gas is modelled by special software and consequences are determined on the basis of results. The first scenario was modelled with help of equations because used software does not include an appropriate model. A farm with high building density was chosen as a model case. Biogas is replaced by methane because used software does not support modelling of dispersion of mixtures. From this viewpoint, a conservative approach is applied because biogas contains “only” approximately 60% of methane (in dependence on technology and processed material).Tento příspěvek popisuje modelování následků úniku bioplynu ze zásobníku na zemědělské bioplynové stanici. Pro účely této práce byly vybrány čtyři scénáře. Porušení membrány plynojemu a okamžitý výbuch plynového mraku, výbuch plynu se zpožděním, vyprázdnění celého objemu plynu (bez iniciace) a únik plynu s iniciací Jet-Fire. Únik plynu je modelován softwarem a důsledky jsou stanoveny na základě výsledků. První scénář byl modelován pomocí rovnic, protože použitý software neobsahuje vhodný model

An Evaluation of On-Tool System for Sanding Dust Collection: Pilot Study

Hazards identification is essential step in framework of occupational health & safety (OH&S) management system. The task of spruce wood sanding with hand-held power belt sander is considered as a significant resource of exposure to wood dust. Dust from spruce wood is hazard that can cause negative health effects such as asthma and chronic bronchitis. A dust collection box is a commonly used technical measure for reducing exposure to wood dust for this task in practice. The objective of this pilot study was to evaluate the effectiveness of commercially available dust collection box at reducing exposure to wood dust during the task of sanding spruce wood using hand-held power belt sander. Laboratory experiment involved sanding spruce planks (250 mm x 50 mm x 500 mm) in longitudinal direction using belt sander (Bosch, PBS 75 A) with 120 grit sanding belt. Spruce dust mass concentrations were sampled using an aerosol monitor (TSI Inc., DustTrak DRX 8533) in the breathing zone of operator. Inhalable and respirable dust concentrations were both significantly lower (P < 0.0001) when dust box was attached to belt sander compared with sander without a dust box. Results from this pilot study indicate that dust collection box is efficient technical measure for decreasing exposure to aerosol mass concentration during sanding spruce wood with hand-held belt sander

The Safety of Biogas Gasholders

Příspěvek se zaměřuje na bezpečnost zásobníků bioplynu. V první části jsou vymezeny konstrukční typy zásobníků, které se využívají na bioplynových stanicích. Další část shrnuje nejčastější příčiny havárií na zásobnících plynných a kapalných uhlovodíků a uvádí je do souvislosti s havarijními situacemi na bioplynových stanicích. Poslední část upozorňuje na základní bezpečnostní zařízení, jimiž musí být tyto zásobníky vybaveny.The work is focused on safety of biogas gasholder. In the fi rst part design types of gasholder utilizing on biogas stations are defi ned. The next part of work summarizes the most common causes of accidents on gasholders of gaseous and liquid hydrocarbons. These causes are given to relationship with emergency situations on biogas plants. The last part warns on elementary safety barriers, which must be included in gear of a gasholder

Rozšíření haly generálních oprav a nástrojárny v n.p. Tatra Čadca

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