The Risk Assessment Model Study Of Storage Tank System In Chemical Enterprises

With the petrochemical industry development and upgrading in China, chemical enterprises gradually develop toward the direction of large-scale equipment, production automation, efficient production, complex process integration. So risk control is facing serious challenges. It is an important basis to keep the operation of the chemical process safe by using the method of system risk assessment to evaluate the risk of chemical process. Furthermore, it not only helps improve the safety management level and ensure the daily production and operation, but also promotes the sustainable development of our society. Talking toluene strage tank system as the research object, the paper asesss the risk, the main research work is following:(1) On the basis of hazard and operability analysis, the risk of storage tank system is identified. The risk factors and events, which may cause a great influence risk consequences, are identified in the storage tank, pressure pipe, transportation,centrifugal pump and the crane tube. Then draw risk identification table.(2) Based on the Layers of Protection Analysis, the relationship of risk factors and risk events existing in the storage tank system is established to analyse the protective layer which can keep risk events from becoming the unexpected consequences.Though combing independent protective layers, the probability of risk occurrence can be calculated. Last, the results of the analysis of Layers of Protective Analysis are compared with the preset risk criteria, and determine the risk is acceptable or not.(3) Depended on the model theory of independent protection layer, an evaluation index system is set up. The first layer includes 7 indicators, which are basic process control system, alarm and personnel intervention, safety instrumented system, physical protection, release of physical protection, factory emergency response, as well as community emergency response and the second layer includes 20 indicators.(4) A risk assessment model is set up based on the theory of the uncertain mathematics to evaluate risk in tuk system. According to the failure probability of the protection layers, index evaluation grade space is set up and single index functions are established. The indexes values are estimated by the quantization of the uncertainty of index functions. The weights for indexes are calculated by information entropy indicating the availing value of data. According to the unascertained measure vector, the risk level of the storage tank system is determined.(5) Take a toluene storage tank system of a Lanzhou chemical industry enterprise as the research object, the applicability of the risk assessment model is validated.Through the analysis of the evaluation results, the risk level of the toluene storage and transportation system is 2, which means “good” as a whole. The risk levels of basic process control system, alarm and personnel intervention, safe instrumented system,release of physical protection and factory emergency response are 2, which mean“good”. The risk of physical protection, and community emergency response are all in 3levels, which mean “normal”. According to the analysis results, this paper puts forward some corresponding suggestions and countermeasures.The model is utilizable to assess the risk of storage and transportation system in different chemical enterprise and analyze other technological processes risk in the same chemical enterprise. The evaluation results play a guiding roles for the safety management of chemical enterprises.