Research On Reliability Analysis And Risk Assessment Of Horizontal Tank Under Flood Disaster

With global warming and sea level rising, extreme flood disasters happened frequently in recent years. As a kind of HILP(high-impact and low-probability) event, once the chemical accidents which is caused by flood disaster is happened, the consequence of accident would be far greater than the accident which is caused by chemical refining failure or human factor. The thesis start the study from the chemical accidents which was caused by flood disaster occurred over the years, through the statistically analysis the accidents occurred over the years abroad, the horizontal cylindrical tank was selected as the typical chemical refining to be the object of study to carry out the risk assessment. The main contents are as follows:(1)Statistics analysis and disaster mechanism research of accidents occurred by flood disaster. Disasters energy transfer theory and disaster chain theory was used to study the mechanism of chemical accidents occurred by flood disasters, the foreign authoritative accident databases was selected as the statistical source to carry out a statistical analysis of chemical accidents occurred by flood disasters.(2)Transient dynamic response of horizontal tank under flood wave load. Linear wave theory was selected to establish numerical calculation model for wave forces; the finite element software ABAQUS was used to carry out the modal analysis of the horizontal tank to evaluate the possibility of resonance; different wave height and different wave incident angle of wave load is applied on the tank, base on the calculating results of the stress and displacement, the dangerous region and the key areas of the tank has been defined.(3)Reliability analysis of horizontal tank under flood wave load. Based on the transient response analysis of horizontal tank under the flood wave load, the joint of tank-support and based was identified as the most vulnerable region. Combined with the structural reliability principle, Monte-Carlo method was used and calculation program was compiled through MATLAB to calculate the limit state equation. Through the parameter sensitivity analysis, the effects of variables on the structural reliability was determined.(4)Study on risk assessment method of horizontal tank under flood disaster. Base on the risk assessment theory of flood disaster, the risk assessment methods of flood disaster and chemical accident was combined to construct the evaluation framework on account of "risk analysis of flood disaster-risk assessment of horizontal tank accident-risk level evaluate" to assess the risk of horizontal tank under the flood disaster.(5)Apply on risk assessment method of horizontal tank under flood disaster. Base on the risk assessment method build above, a LNG horizontal tank of 150m3 in a chemical industrial park which was located in Guangdong province was selected as the application object. Assume the LNG storage tank area suffer worst flood disaster in 50 years, the risk assessment method was used to assess the risk of the possible accidents of the LNG storage tank which was caused by the flood disaster.