The Application Of Risk-Based Inspection Method For Ethylene Cracking Unit

Along with the increase in the number, size, complexity, and variety of equipments in petrochemical industry, the loss of resources and its affection in society have been become more serious, when an event occurs. The old methods of time-based inspections and even condition-based inspections are no longer availability to reduce the frequency of occurrence of any event. On the other hand, the competition between corporations is more severity, and the profit margin plays down. Now plants sharpen focus on extending continued operation time and minimizing maintenance costs. On account of the two requirements of safety and economy, a new safety and cost-benefit methodology used in petrochemical plant inspection and maintenance has been developed.Risk-based Inspection (RBI) is a new inspection technology approach for refineries and processing plants, and gradually adopted these days. It is a systematic method for using risk as a basis for prioritizing and managing the effort of an inspection program. The risk of equipments is determined by the combination of two factors: the consequence of failure and the likelihood of failure. Based on the risk levels and failure mechanism, an inspection planning is provided, primarily by reducing the probability of failure, to reduce the higher risks. In an operating plant, a relatively large percentage of the risk is usually associated with a small percentage of the equipment items. Therefore, inspection efforts can result in not only improvement of plant reliability but also substantial cost savings, allowing a shift of inspection and maintenance resources to provide a higher level of coverage on the higher risk items and an appropriate effort on lower risk equipment.This paper analysis the likelihood and consequence of failure for 7 processes of Ethylene Cracking Unit of Ethylene Plant of Tianjin Petral-Chemical Corporation, including 345 equipments(486 items) and 3,306 pipelines, and then give risk degree and possible different damage mechanisms. According to the result of ethylene RBI project, the...