SPECIFICATIONS FOR PRESSURE VESSELS - THEIR TRENDS AND CHALLENGES FOCUS: HYDRO-PROCESSING REACTORS MADE FROM 2 ¼ Cr 1Mo V (Enhanced Steel)

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1 DILLINGER HÜTTE SYMPOSIUM SPECIFICATIONS FOR PRESSURE VESSELS - THEIR TRENDS AND CHALLENGES FOCUS: HYDRO-PROCESSING REACTORS MADE FROM 2 ¼ Cr 1Mo V (Enhanced Steel) Radoslav Stefanovic Fluor Canada Ltd. Calgary, Alberta Advanced Steels for Boilers & Pressure Vessels Symposium June 21, 2005 Calgary, Alberta, Canada

2 Introduction Transportation Field Fabrication Lifting Fatigue Evaluation 2

3 INTRODUCTION 2 ¼ Cr -1Mo-V V (enhanced steel) is used extensively as material for elevated temperature and pressures hydro-processing reactors Temperatures 427 C 482 C Pressures 18,600 kpa 19,300 kpa 3

4 INTRODUCTION (Cont.) Why is it important to have Vanadium enhanced materials? High High resistance against elevated temperature hydrogen attack High High strength at elevated temperature resulting in reduction in reactor wall thickness and weight 4

5 INTRODUCTION (Cont.) Thickness & weight comparison for 2 ¼ Cr Mo (conventional) vs. 2 ¼ Cr Mo V (enhanced) steels (inside diameter ID = 3660 mm, tangent to tangent T/T = mm) Material ASME VIII DIV Allowable stress in design temperature 427 ºC 454 ºC 482 ºC Thickness design temperature of 454 C Weight (metric tons) 2 1/4 Cr - 1 Mo I 133, , , II 155, , , /4 Cr - Mo - V I 149, , , II 173, , ,

6 Introduction (Cont.) Use of advanced (enhanced) steels reduces: Transportation cost (can be significant and as high as 80% of the reactor cost) Requirement for field fabrication (saving in cost and project duration) Lifting cost Total cost 6

7 TRANSPORTATION Hydroprocessing Reactors are usually fabricated in Japan or Italy Land vs. Sea transportation challenges 7

8 TRANSPORTATION (Cont.) The biggest challenge to bring vessels to Alberta, Canada is rail transportation Restriction in shipping envelope Restriction in weight per axle 8

9 TRANSPORTATION (Cont.) Possible options for rail transportation Conventional shipping in one piece Shipping by Schnabel Car (Owned by Westinghouse, USA) Conventional shipping in two or more pieces 9

10 TRANSPORTATION (Cont.) Rail Transportation restrictions for bringing vessels to Alberta, Canada Maximum weight per axle is 29.5 metric tons 10

11 TRANSPORTATION (Conventional shipping in one piece) 11

12 TRANSPORTATION (Schnabel Car) Largest railroad car in the world Capacity to transport load up to 880 metric tons (also a function of length) Courtesy of Westinghouse 12

13 TRANPORTATION (Schnabel Car ) Load is suspended between two halves of the car Low CofG allows the transport of heavier loads Courtesy of Westinghouse 13

14 TRANSPORTATION (Schnabel Car) Allows transportation of bigger reactors Courtesy of Westinghouse 14

15 TRANSPORTATION (Schnabel Car) Use of Hydraulic system allows equalization of load on the rails and prevents any overturning situation Courtesy of Westinghouse 15

16 TRANSPORTATION (Schnabel Car) Reactor is exposed to high compression and buckling loads approximately of 2,500 metric tons The shell and top nozzle can take this loads because of size and thickness of the reactors Skirt is the most critical component because it is thinner and lower part is manufactured from carbon steel 16

17 TRANSPORTATION (Schnabel Car) F2 F1 F4 F6 F7 F8 F5 F9 F9 FEA Skirt Model 17

18 TRANSPORTATION (Schnabel Car) Displacement 18

19 TRANSPORTATION (Schnabel Car) Stress in Skirt 19

20 FIELD FABRICATION When size and weight of the vessel prohibits the transport in one piece, reactor is transported in two or more pieces and final fabrication is done on site Fabrication of multi-piece reactors can be performed in horizontal or vertical position 20

21 FIELD FABRICATION (Cont.) 21

22 FIELD FABRICATION (Cont.) 22

23 FIELD FABRICATION (Cont.) 23

24 FIELD FABRICATION (Cont.) 24

25 LIFTING Lifting Limitations Crane capacity Access for lifting 25

26 LIFTING (Cont.) 26

27 LIFTING (Cont.) 27

28 LIFTING (Cont.) 28

29 FATIGUE EVALUATION The rules to determine need for fatigue analysis are provided in ASME Section VIII Div. 2; Para. AD-160 AD Operating experience Licensor and owner experience with this material is limited and it is difficult to justify applying this paragraph AD & 3 are applicable for materials having a specified tensile strength not exceeding 552 MPa 2 ¼ Cr - 1Mo - V minimal tensile strength is 586 MPa and Code Case 2306 should be applied 29

30 FATIGUE EVALUATION (Cont.) To find the actual number of cycles, a detail thermal and pressure screening shall be performed for: Commissioning Normal Start-up Normal Shut-down Emergency conditions Steady state operation 30

31 FATIGUE EVALUATION (Cont.) 31

32 FATIGUE EVALUATION (Cont.) ASME Section VIII div 2; Appendix 5 provides fatigue curves valid only for temperatures not exceeding 371 C. The High Pressure Gas Safety Institute of Japan and Kobe Steel, Ltd. published fatigue curves in PVP-Vol Vol 473 (2004). Load and strain controlled fatigue tests were conducted over the range from room temperature to 500 C. Specimens were made from forged rings. 32

33 USER DESIGN SPECIFICATION PREPARATION (Cont.) 33

34 CONCLUSION Transportation Field Fabrication Lifting Fatigue Evaluation 34