基于汽包寿命的1 021 t/h锅炉启动过程的优化研究

1引言300 MW机组已经成为我国火力发电的主要机组。随着用电结构的变化,电网负荷的峰谷差日益增大,许多大容量机组已参予调峰运行。机组在调峰过程中,锅炉启停、变负荷运行使汽包受到交变应力作用,产生低周疲劳损伤。随着机组启停次数的增加,汽包疲劳损伤加剧,给电力生产留下安

A Study of the Optimization of a 1 021 t/h Boiler Start-up Process on the Basis of the Boiler Drum Service Life

By using a three-dimensional finite element theory calculated was the stress field of a 1021 t/h boiler drum under the action of an internal pressure.The theoretical stress concentration factor thus obtained is greater than the recommended value of German TRD301 standard by 22.7%.In addition,the thermal stress of the boiler drum under a quasi-steady state was calculated using the theory of thermal elasticity.By employing TRD301 standard the fatigue life of the boiler drum was calculated.With the time step experienced by the pressure-rise range at various stages serving as an optimized parameter,thereby achieving the dual target of lowering fatigue life loss and shortening start-up time,a model of boiler start-up process optimization was set up based on the boiler drum service life. Through calculations optimized curves were obtained for the 1021 t/h boiler cold-state and hot-state start-up process.On this basis,the practical operation of a 1021 t/h boiler for a 300 MW unit at a certain power plant has brought about satisfactory results.A start-up on the basis of these optimized curves can not only ensure a small loss of boiler drum service life,but also significantly shorten boiler start-up time.The optimized start-up curves set up by the authors can provide significant guidance for the boiler operation of the 300 MW plant.