Application of Accident Tree Analysis Method in Safety Evaluation of LPG Storage Tanks Yan Lanying. Li Hongshi Jiazhuang Xinao Gas Co., Ltd. Hebei Shijia is evaluated by 050200 to find out the main causes of accidents and propose safety precautions.
The safety evaluation of gas engineering is to comprehensively evaluate and predict the dangers and consequences of gas engineering, and propose corresponding safety prevention measures according to the risk of accidents that may be caused to achieve safety accidents. Tree analysis method Fault tree analysis, also known as fault tree analysis, is a deductive system safety analysis method. It starts from the specific incident or fault top event to be analyzed, and may pass the conditions and possible conditions that may occur in the established production system or operation. The resulting disaster consequences, according to the process sequence and causal relationship to draw the accident tree, the small relationship between the various factors leading to disaster damage accidents, the logical analysis of the causes, the structural importance of the calculation of fluoride to identify the accident The basic reason is the bottom event of the fault tree, and determine the importance of each basic event in the process of causing the accident.
The purpose of the accident tree analysis method is to identify the combination of basic events and human errors that lead to accidents, and to provide people with clues to avoid or reduce the basic causes of accidents, thereby reducing the possibility of accidents and causing various flashover logics. The relationship is described as a comprehensive and concise description; it is convenient for logical operations, qualitative and quantitative analysis and systematic evaluation.
The most prominent advantage of the accident tree analysis method is that it can evaluate the probability of an accident and identify the direct cause of the accident, and can analyze the potential cause of the accident.
2 LPG Storage Tanks fire and explosion accident original flash analysis 21 low pressure wet gas storage tank introduction Because the gas stored in the gas storage tank is flammable and explosive, the density is small, the explosion range is wide, and a burning explosion accident will cause human wealth. Serious damage to both injuries. According to the national standard major hazard identification, the critical test of flammable gas storage area is 10, such as 22 0, the coke oven gas storage tank of 1 is a major hazard, so how to prevent the fire and explosion of the LPG Storage Tanks Accidents are the focus of gas company safety. It is of positive significance to evaluate the safety of entering the hall and control the occurrence of the accident.
22 Low-pressure wet gas tank accident tree accident tree analysis is the accident condition that may occur in the established production system or operation and the possible disaster consequences. It is drawn into the program box according to the process sequence and causality, resulting in disaster damage accident. The logical relationship between the various factors provides a collection of the minimum basic events that can cause the top event to occur in the most succinct and succinct way to determine the relationship between the path of disaster damage and the accident factor. It is called the minimum cut set. If the minimum cutting concentration does not occur in the basic mountain pieces, the top 1 event will be. The minimum cuts are the dangers of the system, and each minimum cut set is a possible channel for the top event to occur. The more the minimum number of cut sets, the more dangerous the system is.
Due to the direct cause of the accident, the probability of the event is not easy to count. Therefore, it is very important to do the accident probability calculation but to conduct qualitative analysis to find out the cause of the accident.
Low-pressure wet gas storage tank fire and explosion accident tree, the symbols in the following description T top towel, gas tank fire explosion accident a condition event, coke oven gas concentration reaches the explosion limit V, basic events, electric spark basic events, lightning strike spark, basic Event, impact spark A4 basic event, open flame operation A5 basic parts, chemical fiber product hook body friction, Yh basic event, static accumulation Y7 basic event during release, grounding + good Yti basic event, gas tank over-limit operation, drowning event , cans V water events, derailment, V raft events. The weld has a quality test P. Basic event, the release valve is not tight V, the coffin, the piece, the corrosion perforation V14 basic event, the external force strike, the ignition source B intermediate event, the gas and air contact produces the mixed gas C intermediate event, the static spark D1 Cai, gas eve E intermediate event, tank air F, inspection and release, there are sparks G pieces, connection parts vent, H intermediate events, tank body leakage intermediate events, water seal leakage + logic, logic.
23 gas storage tank fire and explosion accident structure function 41 24 minimum cut set calculation According to the above calculation, the following 42 minimum cut sets can be derived by derivation 1 38 25 structural summary analysis structure importance analysis is from the accident tree structure Analyze the importance of each basic event, that is, analyze the occurrence of each basic event and the occurrence of the top event without considering the probability of occurrence of each basic event, or assuming that the probability of occurrence of each basic event is equal. degree. This is a qualitative importance analysis, which can provide an important information structure for improving the system security. The importance of the approximation is i1 value K, the number of cuts A basic events. Where the cut is concentrated. The order of the number of structural importance of the piece 1 can be judged by the minimum cut set of the accident tree and the small set of points. The basic principle of the basic event of the single-order cut set is the largest; the same one or more The structural importance factor of the event in the minimum cut set is the same; the basic event in the same cut set has a large number of occurrences and a large coefficient of structural importance.
According to the above results, the structural importance degree approximation can be used to discriminate the 14 basic events of Yiyi 14 and the structural congruence coefficient of one conditional event. The specific discriminant coefficient is as follows. Since the conditional event exists in each cut set, its structure is important. The degree coefficient is the largest.
The event is especially 12223 especially 4 especially 5 is the 7-order cut-off set and the 7-order cut-off of the seven pieces of structural importance coefficient, equal, that is, the event is especially 8 especially 9 no, 213 especially 14 is 6 3rd stage damage , the set and the event of a 4th-order cut set, its structural importance coefficient; 8 importance coefficient, 7 equal, that is, the comprehensive calculation result according to formula 1, the order of structural importance coefficient is obtained by the accident tree analysis method, The ignition source and the explosive limit. The conditional event reaches the explosion limit and the structure has the largest importance coefficient. It is the most important condition for gas storage and fire explosion accidents. The basic events constituting the ignition source are insufficient, the structural importance coefficient is second, and the basic safety precautions are based on basic events. The sequence of structural importance can be known that the gas reaches the explosion limit. The ignition source gas leakage is the most important condition for the fire and explosion of the LPG Storage Tanks. The fundamental measure to prevent accidents is to prevent leakage and prevent sparks.
A flammable gas concentration detecting alarm device is installed in the tank 1. And to ensure that it is in normal use under any circumstances, the concentration of the mixture is monitored, 1 close to the dangerous concentration, the hall alarm. Let the manager 0 quickly take precautionary measures to prevent the formation of explosive gas, and strengthen the staff's teaching lights for economical methods. Strengthening safety management, strictly prohibiting smoking and strictly implementing the hot fire system, preventing iron strikes, preventing static sparks, and complying with fireproof and explosion-proof requirements for equipment, is a necessary condition for preventing fire and explosion accidents in low-pressure LPG Storage Tanks.
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