Study On HAZOP Quantitative Analysis

In order to more effectively identify the potential hazard in the petrochemical unit，acomprehensive and quantitative HAZOP (Hazard and Operability) analysis method, inwhich HAZOP was combined with process dynamic simulation, fault tree and riskevaluation, was proposed. The main contributions of the dissertation are summarized asfollow:(1) The principle, specific steps of traditional HAZOP analysis method wasintroduced in this paper. The traditional HAZOP analysis was carried out forthedeisobutane unit in a petrochemical company.(2) The new HAZOP quantitative analysis method was proposed. Firstly, thedeviations and deviation causes are determined through HAZOP analysis. And thedeviations causes are classified according to whether it can be simulated. Then, thedynamic process model is established by using Unisim (the chemical process simulationsoftware). The deviation causes in the HAZOP analysis are simulated by prefabricatedfault. As a result, the quantitative relationship among deviation causes, deviation andconsequences are obtained by process dynamic simulation. Finally, based on the results ofHAZOP analysis and dynamic simulation, the fault tree is established in which thedeviation is taken as top event, and the probability of top event is calculated quantitatively.Three types of deviation consequences including the personnel injury, property damageand environmental impact are consider in the risk evaluation so that the severity level ofdeviation consequences will be determined which is based on the highest severity level ofconsequences. The risk evaluation of deviation is performed by the comprehensive levelof deviation causes probability and the severity level consequences. Then, the safetymeasures are put forward.(3)Three deviations including “much too low of feed flow, much too high liquid levelof reboiler and column overpressure” were choosed as a study case in the deisobutane unitof a petrochemical company, and the quantitative HAZOP analysis was carried out. The deviations of the higher level risk were identified, and then the security protectionmeasures and suggestions were proposed so that the limited resources could be used todeal with deviations of high level risk. Results show that the proposed HAZOPquantitative method can provide quantitative basis for safety management ofpetrochemical plant, and verify the effectiveness of the method proposed in this paper.