Analysis On Control System’s Response To The Leakage Scenario Of Liquid-tank

In the leakage scenario of liquid-tank,the response of the level control system will aggravate leak accident and affect the independence of protection layer,and it often can bring errors to the calculation of scenario frequency and assessment of risk level,this phenomenon is a kind of common cause failure,at the same time also belongs to the category of systemic failure.In the past study of common cause failure mode,the main research object is the random failure of control system component,but there are little researches on the systematic common cause failure when the control system in normal operating condition,the researches on it own an increasingly urgent demand,therefore,this article will combine the concept of the common cause failure and systemic failure to analyze control system’s response to the leakage scenario of liquid-tankBased on the control system(BPCS/SIS)in the liquid-tank leakage scenario as the research object,first of all,through the citing example make conjectures about the effect of control system’s response to the liquid-tank leakage scenario,introducing the concept of systematic common cause failure,and summarized;with the China University of Petroleum(East China)pipe leaking and gas diffusion test experiment system as a platform,carry out the experiment about control system’s response to the liquid-tank leakage to verify conjectures on the citing example,through experiment summary data of leakage intensity contrast leakage intensity change rule before and after the response;selecting tanks(a large gas turbine driving centrifugal compressor unit cyclone process part)as an example,using the experimental phenomenon and law,contrasting domestic and foreign relevant equipment HAZOP/LOPA analysis method,aiming at leakage scenario develop LOPA analysis to compare the control system protection’s response,tell whether such response is negative impact of leakage accident,put forward the logic of systematic common cause failure with reliability block diagram(RBD)to study,at the same time though semi-quantitative assessment analysis,estimate the risk reduction factor(RRF)of existing protection layer and the PFD of protection layer which is needed to add;in analogy to the common cause failure(random failure)β factor,set up ε factor in systematic common cause failure,to evaluate systematic common cause failure;at the same time,using Markov model analyze PFD of the analogous protection layer.Finally,the research is applied to the engineering practice,in view of the uncertainty of control system’s response to the leakage scenario,determine its effect,namely part of control system’s response will lead to leakage intensity increased,compared with no control.Based on the experimental data reach the leakage intensity’s general law when control system response,provide theoretical basis and scientific reference for the LOPA analysis of leakage scenario;combined with HAZOP/LOPA analysis of cases,using the control system leakage scenario influence analysis and systematic common cause failure analysis optimize the leakage scenario LOPA analysis,and establish ε factor for measuring the sensitivity of the control system protection layer affected by the scenario to provide the reference.