Life Estimation And On-line Monitoring For Pressure-bearing Part Of Utility Boiler

With the development of national economy and advancement of living standard in China, electric industry is developing quickly. The initial investment of a power plant is so great that it is significant to assure and extend service life of electric power equipments. As one of the most important parts in the thermal power plant, the utility boiler performance has the crucial impact on the operation of thermal power unit. Pressure-bearing part is 80% of boiler metal, its life has the determining influence on the service life of whole boiler. The life of boiler pressure-bearing part is analyzed and a calculation method is put forward. On this basis, a complete set of boiler service life on-line monitoring and management system is developed. The tube metal temperature which is always an important parameter about on-line life monitoring of boiler pressure-bearing part is investigated .The Knowledge Discovery in Databases (KDD) is applied to life management, which show that KDD plays an important role in life management of utility boiler.For steam drum in which fatigue damage under the alternative stress is main failure manner, The fatigue life mechanisms is analyzed and a short-cut calculation method for on-line monitoring.is put forward in this dissertation A set of boiler drum life on-line monitoring and management system is developed based on Management Information System(MIS) and Distributed Control System(DCS). The system put the stress calculation on the DCS side and lifetime calculation on the MIS side making full usage of the present resource of power plant..For high-temperature heating surface in which creep damage is main breakage manner, the creep life expenditure mechanism is discussed in this dissertation.The life evaluation technique is studied and the position of dangerous points for superheater life monitoring is determined. Based on the above work, an on-line life expenditure monitoring system of boiler pressure-bearing part is developed based on SIS.The tube metal temperature of high-temperature heating surface is studied in detail. Numerical Simulation of the metal temperature of high-temperature Superheater is studied, using the shell model to couple steam and the flue gas fields. As an object of research, one utility boiler is studied to calculate the tube metal temperature of high temperature superheater under the rated load. The results of numerical calculation show it will be feasible to apply the numerical calculation software to calculate the tube metal temperature.For steam/water separator which is creep-fatigue damage, the stress field and the mechanism of the fatigue-creep damage in the course of operating is further studied in this dissertation. Method for high-temperature creep-fatigue damage analysis based on elastic analysis be using numerical simulation calculation is done to start state of one utility boiler of the power plant, and life on-line monitoring and management project according to the result of calculation is worked out.The KDD is applied to lifetime management. With the method combined the attributive fuzzy clustering and association rules mining, a project is designed for deal with the boiler operational data from Supervisory Information System (SIS) to get some useful information. It is feasible and practical in the instance related in detail.