Study On Rotor System Operation Stability Of The Super Large Air Separation Units

Air separation units play an irreplaceable role in petrochemical industry,energy,national defense and other fields.With significant strategic demands of complex air separation equipment by construction of national major projects and important industrial production,air separation units become more and more larger.At present localization and independent innovation of air separation units is promoted vigorously.Rotor system stable operation of units is affected by various faults in the process of running.So it signifies much to study rotor system operation stability of super large air separation units.Researchers all over the world made much study in these fields and made great progress.Multi,coupling,minor and early faults dynamics behavior for super large air separation unit are researched.Dynamics behavior is utilized for fault diagnosis and operation stability evaluation including fault number,type,location,and fault severity.Operation stability margin evaluation system of super large air separation unit is established based on fault rotor dynamics and fault diagnosis technology.Then real-time stability monitoring and product design guidance are provided by the evaluation system.They have very important practical significance and application prospects.The main works are as follows:(1)Multi and coupling faults dynamics behavior of multiple degree of freedom rotor system is researched by combining fixed interface modal synthesis method and numerical solution of nonlinear dynamic equations for complicated structure of super large air separation unit.Effects of fault parameters on the dynamic behavior are studied.The mapping relationship between fault parameters/fault dynamics behavior and fault severity is preliminary established.(2)A quantitative fault diagnosis method based on finite element and harmonic balance theory is proposed for multi-span rotor system in rotating machinery for real-time monitoring and diagnosis of super large air separation unit.Fault locations are located at "nodes",and weak fault locations also can be identified.Effects of bearing stiffness and noise signal on the diagnosis method are studied.Feasibility and effectiveness of the proposed method is verified by numerical experiment and test rig experiment.(3)Based on fault rotor dynamics and intelligent fault diagnosis technology by fuzzy theory,operation stability margin evaluation system of super large air separation unit is established by combining the mapping relationship between vibration characteristics and operation stability and the mapping relationship between fault parameters/fault dynamics behavior and fault severity for stable operation requirement of super large air separation unit.Real-time stability margin and product design guidance are provided by the evaluation system.Effectiveness of the proposed evaluation system is verified by fault detection maintenance in engineering examples.Then operation stability margin evaluation software of super large air separation unit is compiled.(4)Synchronization stability evaluation expert system for stable operation requirement of super large air separation units is developed.Combined cooperative expert system and fuzzy expert system,a large comprehensive cooperative expert system is proposed to solve the problem of multi units synchronization stability evaluation.(5)Dynamic matching method on unbalance of multi-span rotor system for excessive unbalance vibration is proposed to reduce unbalance vibration.Meanwhile,operation stability of units is improved and balance technology of rotor system is increased.