API RP 941-2016 Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants (Eighth Edition).pdf

1、Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical PlantsAPI RECOMMENDED PRACTICE 941 EIGHTH EDITION, FEBRUARY 2016Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local

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20、api.org.iiiContentsPage1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Normative References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21、 . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Operating Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.1 Basis for Setting Integrity Operating Windows . . . . . . . . . . . . . . . .

22、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.2 Selecting Materials for New Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.3 High Temperature Hydrogen Attack (HTHA) in a Liquid Hydrocarbon Phase . . . . .

23、. . . . . . . . . . . . . . . . . . 43.4 Base Material for Refractory-lined Equipment or Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.5 References and Comments for Figure 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24、 . . . . . . . . . . . . 44 Forms of HTHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.2 Surface Decarburization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.3 Internal Decarburization, Fissuring, and Cracking . . . . . . . . .

26、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Factors Influencing Internal Decarburization, Fissuring, and Cracking Caused by HTHA . . . . . . . . . . . . 95.1 Incubation Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27、. . . . . . . . . . . . . . . . . . . . . . . . . . . 95.2 Effect of Primary Stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.3 Effect of Secondary Stresses. . . . . . . . . . . . . . . . . . . . . . . . . .

28、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.4 Effect of Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.5 Effect of Stainless Steel Cladding or Weld Overlay . . . .

29、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Inspection for HTHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136.1 General . . . . . . . . . . . . . . . . . . . . . . .

30、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136.2 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Annex A (info

31、rmative) HTHA of 0.5Mo Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Annex B (informative) HTHA of 1.25 Cr-0.5Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Annex C (inf

32、ormative) HTHA of 2.25Cr-1Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Annex D (informative) Effective Pressures of Hydrogen in Steel Covered by Clad/Overlay . . . . . . . . . . . . . . . 29Annex E (informative) Summary of Inspection

33、Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Annex F (informative) HTHA of Non-PWHTd Carbon Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Annex G (informative) Methodology for Calculating Hydrogen Part

34、ial Pressure in Liquid-filled Piping . . . . . 37Annex H (informative) Internal Company Data CollectionRequest for New Information. . . . . . . . . . . . . . . . . 41Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35、 . . . . . . . . . . . . . . . . . . . 43Figures1 Operating Limits for Steels in Hydrogen Service to Avoid High Temperature Hydrogen Attack . . . . . . . 32 C-0.5Mo Steel (ASTM A204 Grade A) Showing Internal Decarburization and Fissuring in High Temperature Hydrogen Service . . . . . . . . . . . . .

36、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Incubation Time for High Temperature Hydrogen Attack Damage of Carbon Steel (Non-welded or Welded with Postweld Heat Treatment) in High Temperature Hydrogen Service. . . . . . . . . . . . . . . . . 10A.1 Experi

37、ence with C-0.5Mo and Mn-0.5Mo Steel in High Temperature Hydrogen Service . . . . . . . . . . . . . 16vContentsPageA.2 Steels in High Temperature Hydrogen Service Showing Effect of Molybdenum and Trace Alloying Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22A.3 Incubation Time for High Temperature Hydrogen Attack Damage of 0.5Mo Steels in High Temperature Hydrogen Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39、 23B.1 Operating Conditions for 1.25Cr-0.5Mo Steels That Experienced High Temperature Hydrogen Attack Below the Figure 1 Curve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26C.1 Operating Conditions of 2.25Cr-1Mo Steels That Exp

40、erienced High Temperature Hydrogen Attack Below the Figure 1 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28F.1 Operating Conditions for Carbon Steel (Welded with No PWHT) That Experienced HTHA Below the 1977

41、Carbon Steel Figure 1 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35TablesA.1 Operating Conditions for C-0.5Mo Steels That Experienced High Temperature Hydrogen Attack Below the 0.5Mo Steel Curve in Figure A.1 . . . . . . . . . .

42、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21A.2 References Along with Chromium, Molybdenum, Vanadium and Molybdenum Equivalent Values for Figure A.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43、. . . . . . . . . . . . 24B.1 Experience with HTHA of 1.25Cr-0.5Mo Steel at Operating Conditions Below the Figure 1 Curve. . . . . 25C.1 Experience with High Temperature Hydrogen Attack of 2.25Cr-1Mo Steel at Operating Conditions Below the Figure 1 Curve . . . . . . . . . . . . . . . . . . . . . . .

44、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27E.1 Summary of Ultrasonic Inspection Methods for High Temperature Hydrogen Attack . . . . . . . . . . . . . . . 31E.2 Summary of Non-ultrasonic Inspection Methods for High Temperature Hydrogen Attack . . . . . . . . . . . 33G.1 Effec

45、tive Hydrogen Partial Pressures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39G.2 Effective Hydrogen Partial Pressures with the Composition Variation + Compensation Method. . . . . . 40viIntroductionAt normal atmospheric temperatures,

46、gaseous molecular hydrogen does not readily permeate steel, even at high pressures. Carbon steel is the standard material for cylinders that are used to transport hydrogen at pressures of 2000 psi (14 MPa). Many postweld heat treated carbon steel pressure vessels have been used successfully in conti

47、nuous service at pressures up to 10,000 psi (69 MPa) and temperatures up to 430 F (221 C). However, under these same conditions, highly stressed carbon steels and hardened steels have cracked due to hydrogen embrittlement.The recommended maximum hydrogen partial pressure at atmospheric temperature f

48、or carbon steel fabricated in accordance with the ASME Boiler and Pressure Vessel Code is 13,000 psia (90 MPa). Below this pressure, carbon steel equipment has shown satisfactory performance. Above this pressure, very little operating and experimental data are available. If plants are to operate at

49、hydrogen partial pressures that exceed 13,000 psia (90 MPa), the use of an austenitic stainless steel liner with venting in the shell should be considered.At elevated temperatures, molecular hydrogen dissociates into the atomic form, which can readily enter and diffuse through the steel. Under these conditions, the diffusion of hydrogen in steel is more rapid. As discussed in Section 4, hydrogen reacts with the carbon in the steel to cause either surface decarburization or internal decarburization and fissuring, and eventual cracking. This form of hydrogen damage is called high temper