在役含缺陷冷凝器的定量風(fēng)險評價.pdf

1、南京工業(yè)大學(xué)碩士學(xué)位論文在役含缺陷冷凝器的定量風(fēng)險評價姓名：夏侃申請學(xué)位級別：碩士專業(yè)：安全技術(shù)與工程指導(dǎo)教師：蔣軍成20060501碩士學(xué)位論文 iABSTRACT The first stage condenser of oxidation reactor system is the key pressure vessel in PTA equipment system. It is very important and neces

2、sary to evaluate the structure with defects and to predict the residual life and to assess the in-service risk. In this dissertation the stress distribution of C3 butt-joint with misalignment was analyzed by FEA method,

3、fracture safety of C3 weld and C2 weld was evaluated by fracture mechanics, the residual life of condenser was predicted by cycle by cycle method and in-service risk was assessed by the combination method with risk analy

4、sis method of API 581 and probabilistic fracture mechanics method. The main conclusions are as follows: (1) Based on the measured data of misalignment, the calculation model was established by ANSYS5.7. From the FEA resu

5、lts, it is found that the maximum stress location was in the maximum misalignment area. For the whole structure, C3 weld is the most weakness location. Under the design pressure, the stress intensity is greater than the

6、allowable stress intensity, which can not be accepted by the standard of JB 4732-95. However, under the operation pressure, the stress intensity is less than the allowable stress intensity, which can be accepted by the

7、standard of JB 4732-95. (2) According to the worst condition modeling, the most serious defect of C3 weld is located between 44# X-ray film and 52# X-ray film, which can be expressed as a surface defects with 1220mm in l

8、ength and 2mm in depth. And there are two most serious defects for C2 weld. One is located between 24# X-ray film and 34# X-ray film, which can be expressed as a submerged defects with 1165mm in length and 1mm in depth.

9、The other is located between 68# X-ray film and 80# X-ray film, which can be expressed as a submerged defects with 1155mm in length and 1mm in depth. The whole defects were assessed by FAD technology, and the assessment

10、points were all located in the safety area of FAD diagram. Therefore, in the view of fitness for service (FFS principle) these defects can be accepted. (3) Based on the fatigue crack growth rate testing for weldment, it