过热器减温器弯头外弧严重扁平的分析及安全性评定

ANALYSIS OF SERIOUSLY FLATTENED OUTER ARC FOR ELBOW BEND PIPES IN DESUPPERHEATERS AND SAFETY EVALUATION THEREOF

云浮发电厂4号炉过热器二级减温器8个弯头外弧均严重呈扁平状,在对这些弯头进行了圆度测量、壁厚测量和无损检验后,根据GB922288《水管锅炉受压元件强度计算》和DL/T50541996《火力发电厂汽水管道设计技术规定》,分别对这些弯头的壁厚进行了校核计算,以及用有限元方法对其结构应力和薄膜应力进行了计算。在综合各种测量、检验及计算结果的基础上,认为这8个弯头目前尚能安全运行。

The outer arc of eight elbow bent pipes in a two-stage desuperheater of the superheater for boiler no.4 in Yunfu Power Plant had been seriously flattened, after circularity measurement, thickness measurement, and non-destrutive inspection of said elbow bent pipes, on the basis of GB 9222-88 《Strength calculation of pressurized parts for water tube boilers》, and DL / T 5054-1996 《Technical specifications for designing steam-water pipelines in thermal power plants》, the thickness of the said elbow bend pipes has been calculated for verification respectively, as well as structural stress and film stress of them being computed by using finite element method. Based on synthesizing various results of measurement, inspection, and calculation, it is believed that the said eight elbow bend pipes can still be safe and reliable in operation at present.