1、Materials, Fabrication, and Repair Considerations for Hydrogen Reformer Furnace Outlet Pigtailsand ManifoldsAPI TECHNICAL REPORT 942-AFIRST EDITION, JUNE 2014Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local,state, and fed
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10、merican Petroleum InstituteForewordNothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for themanufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anythingcontained in the publication be c
11、onstrued as insuring anyone against liability for infringement of letters patent.Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW,Washington, DC 20005, standardsapi.org.iiiivContentsPage1 Scope . . . . . . . . . . . . . . . . . . . . . . . .
12、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Technical Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Results of Literat
13、ure Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14、 . . . . . . 23.2 Materials Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.3 Welding Consumable Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15、 . . . . . . . . . . . . . . . . . 73.4 Welding and Repair Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.5 Mechanical Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.6 Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Results of Industry Survey. . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.2 Designers of Reformers . . . . . . .
18、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.3 Location of Outlet Manifold and Pigtails Relative to Firebox. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.4 Age Distribution of Reformers. . . .
19、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204.5 Operating Conditions: Temperature, Pressure, and Cyclic Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204.6 Manifold System Alloys . . . . . . . . . . . . . . .
20、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214.7 Pigtail Alloys and Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224.8 Inspection Programs. . . . . .
21、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234.9 Repairs, Modifications, or Upgrades. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234.10 Stress-rupture
22、 Behavior of Alloys and Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Industry Case Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285.1 General
23、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285.2 Case 1: Creep Cracking of Bull Tee to Header Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24、. 285.3 Case 2: Creep Failure of Outlet Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.4 Case 3: Pigtail Ruptures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、. . . . . . . . 355.5 Case 4: Stress Relaxation Cracking of Alloy 800HT Pigtail Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355.6 Case 5: Weldability Issues with Cast 20Cr-32Ni-Nb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355.7 Case
26、 6: Repair and Mitigation of Cast 20Cr-32Ni-Nb Tees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395.8 Case 7: Cracking at Weld Between an Alloy 800HT Forged Fitting and an Alloy 800HT Outlet Transfer Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 Acknowledgments. . . . . . . . . . . . .
28、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Annex A (informative) Analysis of Stress-rupture Data Using Larson-Miller Parameter . . . . . . . . . . . . . . . . . . 45Bibliography . . . . . . . . . . . . . . . . . . . . . . . .
29、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Figures1 Example of HAZ Liquation Cracking in Aged 20Cr-32Ni-Nb Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Example of Reheat Cracking in Aged 20Cr-32Ni-Nb Cas
30、ting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Location of Cracking in Aged 20Cr-32Ni-Nb Cast Tee Piece after Welding a New Cone Piece to it . . . . 124 Example of Cracking at Subheader to Tee Weld; Both Are 20Cr-32Ni-Nb Castings . . . . . . . . . . . . . . . . . 135
31、 Typical Pressure and Temperature Ranges for Steam-Methane Reforming . . . . . . . . . . . . . . . . . . . . . . . 136 Typical Designs of Outlet Manifold Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Typical Designs of Outlet Pigtail Sy
32、stems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 Distribution of Reformer Designers in Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Age Distribution of Reformers in Survey . .
33、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20vContentsPage10 Ranges of Operating Temperature for Reformers in Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2111 Ranges of Operating Pressure for Reformers in Sur
34、vey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2212 Stress-rupture Curves for the 20Cr 32Ni Nb Alloy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2413 Comparison of Stress-rupture Behavior of Hot-manifold Alloys and Weldm
35、ents at 816 C (1500 F) . . 2714 Comparison of Stress-rupture Behavior of Hot-Manifold Alloys and Weldments at 871 C (1600 F) . . 2815 Comparison of Stress-rupture Behavior of Hot-manifold Alloys and Weldments at 927 C (1700 F) . . 2916 Comparison of Stress-rupture Behavior of 2133 Mn and 21/33 So We
36、lds with That of 21Cr-32Ni-Nb Alloy Base Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3017 Drawing of Central Portion of Outlet Manifold Showing Central Portion of Header, Bull Tee, andIncreaser
37、Cone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3018 Photograph of Bull Tee Showing Areas Where Cracking of Welds Was Observed . . . . . . . . . . . . . . . . . 3119 Results of Finite-element Stre
38、ss Analysis of Outlet Manifold for Internal Pressure Loading of 1862 kPa (270 psig) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3120 Photomicrograph of Creep Cracking and Voids Observed in Bull Tee Weld .
39、 . . . . . . . . . . . . . . . . . . . . . . 3221 Photograph of Cracking Observed in Ring Section from Outlet Header . . . . . . . . . . . . . . . . . . . . . . . . . . 3322 Photomicrograph of Creep Cracking at Crack Location Shown in Figure 21 (As-polished) . . . . . . . . . . 3323 Photomicrograph
40、of Aligned Creep Voids Near Outer Surface on Side Opposite Cracking of Header Ring Section Shown in Figure 21 and Figure 22 (As-polished) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3424 Photomicrograph of Creep Cracking on Surface of Header as Seen on Metallographic Replica
41、. . . . . . 3425 Photograph of Alloy 800HT Inlet Pigtail and Attachment Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3626 Photograph of Cracking of Alloy 800HT Inlet Pigtail Shown in Figure 25 . . . . . . . . . . . . . . . . . . . . . . . . . 3627 Photomicrograph of Crac
42、k in Alloy 800HT Inlet Pigtail Showing Evidence of Stress Relaxation Cracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3728 Photomicrograph of Showing Typical Aged Microstructure of 2
43、0Cr-32Ni-Nb Cone Material . . . . . . . . . 3829 Photomicrograph Showing Evidence of Liquation Cracking in Weldability Test Sample of Aged 20Cr-32Ni-Nb Cone Material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3830 Phot
44、omicrograph Showing Evidence of Reheat Cracking in Weldability Test Sample of Aged 20Cr-32Ni-Nb Cone Material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3931 Photograph of Showing Locations of Old Tee and New Reducer C
45、one in 20Cr-32Ni-Nb Outlet Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4032 Photograph of Showing Location of Cracking That Occurred When New Centrifugally Cast 20Cr-32Ni-Nb Reducer Cone W
46、as Welded to Old 20Cr-32Ni-Nb Statically Cast Tee . . . . . . . . . . . . . . . . . 4033 Photograph Showing Cracking That Was Found in Base Metal of Old 20Cr-32Ni-Nb Statically Cast Tee after Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47、. . . . . . . . . . . . . . . . . 4134 Cracking at the Weld Joint Between an Alloy 800HT Forged Fitting, and an Alloy 800HT Outlet Transfer Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Tab
48、les1 Chemical Composition and Grain Size Requirements for the Variants of Alloy 800. . . . . . . . . . . . . . . . . . 32 Specifications of Typical Welding Consumables for Hydrogen Reformer Outlet Manifolds and Pigtails. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Chemical Compositions of Weld Metals Used in Hydrogen Reformer Outlet Manifolds and Pigtails . . 114 Typical Chemical Compositions of the 20Cr-32Ni-Nb Alloy and Chemical Composition of a Modified HT Alloy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24vi1 Materials, Fabrication, and Repair Considerations for Hydrogen Reformer Furnace Outlet Pigtails and Manifolds 1 Scope The American Petroleum Institute (API) Co
