英语翻译The cooling process can take from a matter of minutes to

英语翻译The cooling process can take from a matter of minutes to a few hours,depending on the porosity of the coke bed and the quench water feed rate,with a process cycle time of the order of 15 h.Thermal strains imposed on the drums over a number of operational cycles,lead to crack initiation,predominantly at the circumferential strake weldments,and subsequent crack propagation with the risk of through wall penetration.ERA has been performing coke drum life assessments for clients world-wide for over 10 years [1].This paper highlights the current ERA analytical route and methodology for the probabilistic life assessment of coke drums (Sections [2 Phased assessment approach] and [3 General life assessment methodology]).On the basis of this methodology,in-house software has been developed (Sections [4 Details of analysis route:core algorithm of the software] and [5 Monte Carlo]).The successful application of the software to a coke drum assessment is presented here as a case study (Section 6).2.Phased assessment approachThe current ERA life assessment method for coke drums is based upon a phased approach:1.Historical records and monitoring.Inspection and maintenance records,in conjunction with operator experience,are used to identify critical locations on the drum.High temperature strain gauges (thermally compensated) and thermocouples are then installed at these locations.2.Data collection and analysis.Strain gauge output is used to establish the cyclic response of the drum over a series of operational cycles.The data,interpreted as strain amplitudes,provide input to the life assessment algorithm.In conjunction with the local temperature response and an operational data overlay,these readings provide a detailed understanding of the operational cycle of the drum.This can form the basis for preliminary recommendations,with regard to cycle optimisation in respect of the cooling procedure,to minimise thermal strains and extend operational lifetime.3.Life assessment study.Probabilistic life assessment was undertaken on the basis of the monitored strains and temperature response.4.Data re-analysis.Maximisation of drum yield requires short cycle times and rapid cooling rates at the end of each operational cycle,which is in direct conflict with the requirements for life extension.Changes in operational practice are evaluated both in the context of process optimisation and drum life extension.