Development and Application of High Temperature Coke Drums Structure Health Monitoring System

Abstract

The coke drum, work under high temperature, coke in and out with hot and cold distress through the cycle of 495℃ to 50℃, is the core reactor of the delayed coking device. Typical failure modes of bulge deformation of tower, low cycle fatigue crack of weld, material aging, the tower body bending and inclining is easy to be caused under the comprehensive impact of complex load condition, temperature stress and mechanical stress of coke drums, which is a serious threat to safety production. As the requirements for long period running of the refining enterprise continue to improve, the problem of inconsistencies and incongruity of the traditional periodic inspection period and equipment maintenance cycle is becoming more and more prominent. How to meet the stable operation, long period running and ensure the safety and steady operation of the equipment is a great problem. Aiming at the typical failure modes of coke drums during operation, a health monitoring system for high temperature coke drum structure is designed and developed in this paper, which integrates strain, crack, vibration, temperature and other monitoring means. To analyze and calculate the fatigue damage degree, an improved random load spectrum rain flow counting analysis method is proposed, and a damage model based on memory degradation miner criterion is also established. In addition, good results have been achieved with the system applied on the coke drum of a large petrochemical enterprise. The abnormal conditions such as active defects, bending and inclination of the tower body have been found in time during operation, and the healthy state of the coke drum structure has also been diagnosed based on the method proposed in this paper. The system developed in this paper lays a technical foundation for further developing of damage trend forecasting and predictive maintenance for key parts of coke drum structure, and effectively guarantees long-term safe, healthy and stable operation of coke drums.