1、 A Study of Corrosion in Hydroprocess Reactor EffluentAir Cooler SystemsAPI PUBLICATION 932-ASEPTEMBER 2002A Study of Corrosion inHydroprocess Reactor Effluent Air Cooler SystemsDownstream SegmentAPI PUBLICATION 932-ASEPTEMBER 2002SPECIAL NOTESAPI publications necessarily address problems of a gener
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13、L Street, N.W., Washington, D.C. 20005.Copyright 2002 American Petroleum InstituteFOREWORDAPI publications may be used by anyone desiring to do so. Every effort has been made bythe Institute to assure the accuracy and reliability of the data contained in them; however, theInstitute makes no represen
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15、e invited and should be submitted to the standardization manager ofthe Standards Department, American Petroleum Institute, 1220 L Street, N.W., Washington,D.C. 20005, standardsapi.org.iiiCONTENTSPage1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16、. . . . . . . . . . . 12 PREAMBLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1975 NACE SURVEY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1996 UOP SURVEY . . . . . .
17、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 1998 API SURVEY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75.1 Preliminary SurveyBroad Overview . . . . . . . . . . . . . . . . . . . . . . .
18、 . . . . . . . . . . 75.2 Interview Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105.3 Reactor Effluent Air Coolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.4 REAC Inlet and Outlet Piping . . . .
19、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.5 Water Wash Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225.6 Water Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、. . . . . 235.7 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235.8 Corrosion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255.9 Alloy Substitution to Prevent
21、Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255.10 Inhibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276 DISCUSSION AND ANALYSIS OF SURVEY RESPONSES . . . . . . . . . . . . . . . . . 276.1 General Equi
22、pment Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276.2 Nitrogen Content of the Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276.3 Salt Deposition and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23、. . . . . . . . . 286.4 Management of Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286.5 Factors Influencing Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286.6 Corrosion Control . . . . . . . . . . . . . . .
24、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296.7 Water Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296.8 Corrosion Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、 . . . 306.9 Flow Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 FUTURE RESEARCH . . . . . . . . . . . .
26、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31APPENDIX A PLOTS OF CORROSION SEVERITY VERSUS VARIOUS PARAMETERS FROM THE UOP SURVEY DATA FOR ALL COOLER TUBES (REFERENCE 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . 33APPENDIX B PLOTS OF CORROSION SEVERITY VERS
27、US VARIOUS PARAMETERS FROM THE UOP SURVEY DATA FORREAC PIPING (REFERENCE 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37APPENDIX C QUESTIONNAIRE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Figures1 Effect of Kpon REAC Tube Corrosion (from Ref
28、. 7) . . . . . . . . . . . . . . . . . . . . . . . 42 Effect of NH4HS Concentration in the Downstream Separator on REACTube Corrosion (from Ref. 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Effect of Velocity on REAC Tube Corrosion (from Ref. 7) . . . . .
29、 . . . . . . . . . . . . . . 6vPage4 Preliminary Survey of Subcommittee Participants for Levels of Experience . . . . . 8A-1 Corrosion of Air Cooler TubesThe Combined Effect of Calculated Ammonium Bisulfide Concentration in the Downstream Separator and Calculated Maximum Tube Velocity (ft/s) on Corr
30、osion Severity. . . . . . . . . . . . . 34A-2 Corrosion of Air Cooler TubesThe Combined Effect of Calculated Ammonium Bisulfide Concentration in the Downstream Separatorand Calculated Maximum Tube Velocity (ft/s) on Corrosion Severityfor Balanced and Unbalanced Headers. . . . . . . . . . . . . . . .
31、 . . . . . . . . . . . . . . . . . . 34A-3 Corrosion of Air Cooler TubesThe Combined Effect of Calculated Ammonium Bisulfide Concentration in the Downstream Separator andCalculated Maximum Tube Velocity (ft/s) on Corrosion Severity for Balanced Header Systems. . . . . . . . . . . . . . . . . . . . .
32、 . . . . . . . . . . . . . . . . . . . . . . . 35A-4 Corrosion of Air Cooler TubesThe Combined Effect of CalculatedAmmonium Bisulfide Concentration in the Downstream Separator and Calculated Maximum Tube Velocity (ft/s) on Corrosion Severity for Balanced Inlet and Unbalanced Outlet Header Systems .
33、. . . . . . . . . . . . . . . . . . . 35A-5 Corrosion of Air Cooler TubesThe Combined Effect of CalculatedAmmonium Bisulfide Concentration in the Downstream Separator andCalculated Maximum Tube Velocity (ft/s) on Corrosion Severity for Unbalanced Header Systems. . . . . . . . . . . . . . . . . . . .
34、 . . . . . . . . . . . . . . . . . . . . . . 36B-1 Corrosion of REAC Outlet HeaderThe Combined Effect of CalculatedAmmonium Bisulfide Concentration in the Downstream Separator andCalculated Maximum Outlet Header Velocity (ft/s)on Corrosion Severity . . . . . . 38B-2 Corrosion of REAC Outlet Header o
35、r PipingThe Combined Effect ofCalculated Ammonium Bisulfide Concentration in the Downstream Separator and Calculated Maximum Velocity (ft/s) in the Outlet Headeror Piping on Corrosion Severity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38B-3 Corrosion of REAC Outle
36、t PipingThe Combined Effect of Calculated Ammonium Bisulfide Concentration in the Downstream Separator andCalculated Maximum Outlet Piping Velocity (ft/s) on Corrosion Severity . . . . . . 39B-4 Corrosion of REAC Outlet HeaderThe Combined Effect of Calculated Ammonium Bisulfide Concentration in the
37、Downstream Separator andCalculated Maximum Outlet Header Velocity (ft/s) on Corrosion Severityfor Balanced and Unbalanced Header Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 39B-5 Corrosion of REAC Outlet HeaderThe Combined Effect of Calculated Ammonium Bisulfide Concentration in th
38、e Downstream Separator and Calculated Maximum Outlet Header Velocity (ft/s) on Corrosion Severityfor Balanced Header Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40B-6 Corrosion of REAC Outlet HeaderThe Combined Effect of Calculated Ammonium Bisulfide Con
39、centration in the Downstream Separator andCalculated Maximum Outlet Header Velocity (ft/s) on Corrosion Severity for Balanced Inlet and Unbalanced Outlet Header Systems . . . . . . . . . . . . . . . . . 40B-7 Corrosion of REAC Outlet HeaderThe Combined Effect of CalculatedAmmonium Bisulfide Concentr
40、ation in the Downstream Separator and Calculated Maximum Outlet Header Velocity (ft/s) on Corrosion Severity for Unbalanced Header Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Tables 1 Summary of REAC Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41、 . . . . . . . . 32 Preliminary Survey Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Summary of Preliminary Survey Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Preliminary Survey Results (Showing Only Units Selected f
42、or Site Visits) . . . . . 11viPage5 Summary of Preliminary Survey Results (Showing Only Units Selected for Site Visits) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Compilation of Information from Plant Interviews . . . . . . . . . . .
43、 . . . . . . . . . . . . . 147 Compilation of Information from Plant InterviewsAir Cooler Tubes . . . . . . . . 178 Air Cooler Tube Experience from Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 Compilation of Information from Plant InterviewsPiping Information. . . . . . .
44、 1910 Piping Experience from Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2011 Wash Water Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2112 Inspection Summary . . . . . . . . . . . . . . . . . . . .
45、. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2413 Corrosion Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26vii1A Study of Corrosion in Hydroprocess Reactor Effluent Air Cooler SystemsThis study was sponsored by the American Petro
46、leumInstitute (API), Committee on Refinery Equipment, Subcom-mittee on Corrosion and Materials Research. The purpose ofthe study was to provide technical background, based onindustry experience and consensus practice, for controllingcorrosion in hydroprocess reactor effluent systems. The find-ings r
47、eported herein will be used as an interim resource by theindustry and as a basis for a future API recommended prac-tice document.1 IntroductionThe treatment of crude distillation products with hydrogento produce higher yields of gasoline and jet fuel became amajor part of refinery technology with th
48、e introduction ofhydrocracking in the 1950s. Later, other hydrofining pro-cesses for removal of impurities from products were intro-duced. These technologies all had similar corrosionexperiences that eventually were identified as being associ-ated with the presence of hydrogen sulfide (H2S) and ammo
49、-nia (NH3), and their reaction product ammonium bisulfide(NH4HS), in the reactor effluents. Minor contaminants suchas chlorides and oxygen were also believed to have an influ-ence on corrosion. But in general, corrosion was associatedwith salt deposition, concentrated solutions of ammoniumbisulfide and the flow velocity.In 1976, R. L. Piehl (Standard Oil of California) conducteda survey for the National Association of Corrosion Engineers(NACE) on corrosion in Reactor Effluent Air Cooler (REAC)systems. Industry-wide experience was gathered and ana-lyzed to establish guidel
