API Coke Drum Survey Report doc 1996 API Coke Drum Survey Final Report NOVEMBER 2003 Copyright American Petroleum Institute Provided by IHS under license with API Not for ResaleNo reproduction or netw[.]
1996 API Coke Drum Survey Final Report `,,-`-`,,`,,`,`,,` - NOVEMBER 2003 Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale 1996 API Coke Drum Survey Final Report `,,-`-`,,`,,`,`,,` - NOVEMBER 2003 FOR AMERICAN PETROLEUM INSTITUTE Subcommittee on Inspection Coke Drum Task Group By Capstone Engineering Services, Inc Houston, TX Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale Contents Page Summary v Background .vii 1.0 General Information 2.0 Design 3.0 Coke Drum Operation 4.0 Inspection Practices 5.0 Deterioration Experience 5.1 Skirt Deterioration 5.2 Shell Bulging 5.3 Shell Cracking 5.4 Cladding and Cracking 6.0 Repair Procedures 6.1 Skirt Attachment 6.2 Shell Repairs 6.3 Cladding Repairs 7.0 Trends and Correlations 7.1 Material Design Trends 7.2 Dimensions Trends 15 8.0 Materials and Design Compared to Drum Cracking Experience 19 8.1 Shell Materials 19 8.2 Drum Design Dimensions vs Cracking 23 9.0 Material and Design Compared to Drum Bulging Experience 28 9.1 Drum Design Dimensions vs Bulging 29 9.2 Cladding Performance 29 10.0 Skirt Deterioration Versus Materials and Design 38 11.0 Operating Parameters Versus Cracking Experience 42 12.0 Bulging Versus Operating Parameters 53 13.0 Future Survey Recommendations 53 Figures 3.01 3.02 3.03 Current Fill Cycle Times 5.1 7.01 Trend of Material Selection (Skirt) (Combined Chrome Moly) 11 7.02 Trends of Material Selection (Skirt Material) 11 7.03a Trend of Material Selection (Shell and Cone) 12 7.03b Trends of Material Selection (Shell/Cone Material) 12 7.04a Trend of Material Selection (Shell and Cone) 13 7.04b Trends of Material Selection (Shell/Cone Material) 13 7.05 Trend of Material Selection (Shell/Cone Cladding) 14 7.06 Trends of Material Selection (Shell/Cone Cladding) 14 7.07 Trends of Material Selection (Weld used to join Cladding) 15 7.08 Skirt Wall Thickness vs Installation Year 16 7.09 Shell Thickness (Bottom Course) vs Installation Year 16 7.10 Drum Diameter vs Installation Year 17 7.11 Diameter Wall Thickness (Bottom Course) vs Installation Year 17 7.12 Drum Height (T-T) vs Installation Year 18 7.13 Drum Capacity vs Installation Year 18 8.01a Number of Surveys Reporting First Through Wall Crack 20 8.01b Percent of Surveys Reporting First Through Wall Shell Crack 20 8.01c Number of Drums Reporting First Through Wall Crack 21 8.01d Percent of Drums Reporting First Through Wall Shell Crack 21 8.01e Shell Materials vs Cycles to First Through Wall Crack 22 8.01f Materials vs Cycles to First Through Wall Crack 22 `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS i Not for Resale Page 8.02 8.03 8.04 8.05 8.06 8.07 8.08 9.01a 9.01b 9.01c 9.01d 9.01e 9.01f 9.02 9.03 9.04 9.05 9.06 9.07 9.08 9.09 9.10 9.11 10.01 10.02 10.03 10.04 10.05 11.01a 11.01b 11.01c 11.02 11.03 11.04 11.05 11.06 11.07 11.08 11.09 11.10 11.11 11.12 11.13 11.14 11.15 11.16 11.17 12.01a 12.01b 12.01c 12.02a 12.02b 12.02c 12.03 12.04 12.05 12.06a 12.06b Diameter vs Cycles to First Through Wall Crack 24 Drum Wall Thickness vs Cycles to First Through Wall Crack .24 Diameter/Thickness vs Cycles to First Through Wall Crack 25 Total Number of Cracks vs Operating Cycles .25 Total Number of Cracks vs Operating Cycles and Materials .26 Number of Through Wall Cracks vs Operating Cycles 26 Number of Through Wall Cracks vs Operating Cycles and Materials 27 Number of Surveys Reporting First Shell Bulge .30 Percent of Surveys Reporting First Shell Bulge .30 Number of Drums Reporting First Shell Bulge .31 Percent of Drums Reporting First Shell Bulge 31 Material vs Cycles to First Bulge 32 Material vs Cycles to First Bulge 32 Diameter vs Cycles to First Bulge 33 Wall Thickness vs Cycles to First Bulge 33 Diameter/Thickness vs Cycles to First Bulge 34 Number of Bulges vs Total Cycles 34 Number of Bulges vs Operating Cycles .35 Number of Bulges vs Diameter .35 Number of Bulges vs Diameter/Thickness 36 Histogram of Bulge and Crack Distribution 36 Histogram of Bulging Depth 37 Occurrence of Disbonding 37 Skirt Bulging Status vs Material and Operating Cycles 39 Material vs Cycles to First Skirt Crack 39 Skirt Cracking Status vs Material and Operating Cycles .40 Skirt Cracking Status vs Cycles and Skirt Thickness 40 Skirt Compressive Stress vs Cycles to First Skirt Crack .41 Cycles to First Through Wall Crack vs Initial Quench Rate 43 Cycles to First Through Wall Crack vs Initial Quench Rate/Diameter 43 Cycles to First Through Wall Crack vs Initial Quench Flux 44 Number of Cracks vs Initial Quench Flux 44 Number of Cracks vs Initial Quench Rater over Diameter 45 Cycles to First Through Wall Crack vs Proofing Rate 45 Number of Cracks vs Proofing Rate 46 Total Number of Cracks vs Total Cycles .46 Cycles to First Through Wall Crack vs Final Quench Rate 47 Number of Cracks vs Final Quench Rate 47 Cycles to First Through Wall Crack vs Furnace Outlet Temperature 48 Number of Cracks vs Furnace Outlet Temperature 48 Cycles to First Through Wall Crack vs Sulfur Content 49 Number of Cracks vs Sulfur Content 49 Cycles to First Through Wall Crack vs Quench Overhead Pressure 50 Number of Cracks vs Quench Overhead Pressure .50 Current Fill Time vs Cycles to First Through Wall Crack 51 Steam Strip Time vs Cycles to First Through Wall Crack .51 Hydrocarbon Vapor Preheat Time vs Cycles to First Through Wall Crack 52 Cycles to First Bulge vs Initial Quench Rate 54 Cycles to First Bulge vs Initial Quench Rate Over Diameter 54 Cycles to First Bulge vs Initial Quench Rate 55 Number of Bulges vs Initial Quench Rate .55 Number of Bulges vs Initial Quench Rate Over Diameter .56 Number of Bulges vs Initial Quench Flux 56 Cycles to First Bulge vs Proofing Rate 57 Number of Bulges vs Proofing Rate 57 Number of Bulges vs Total Cycles 58 Cycles to First Bulge vs Final Quench Flux 58 Cycles to First Bulge vs Final Quench Flux 59 ii Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS `,,-`-`,,`,,`,`,,` - Not for Resale Page 12.07a 12.07b 12.08 12.09 Number of Bulges vs Final Quench Rate 59 Number of Bulges vs Final Quench Rate 60 Cycles to First Bulge vs Furnace Outlet Temperature 60 Number of Bulges vs Furnace Outlet Temperature 61 Tables 2.01 2.02 2.03 5.1.1 5.2 5.3 8.01 9.01 9.02 Frequency of Material Selection for Shell and Cone Materials Frequency of Material Selection for Cladding Materials Frequency of material Selection for Welding Clad Materials Skirt Cracking Results Maximum and Average Bulge Results Drums with Either Cracking or Bulging Only Cycles to First Through Wall Crack 19 Cycles to First Bulge 28 Occurrence of Disbonding 29 `,,-`-`,,`,,`,`,,` - iii Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale `,,-`-`,,`,,`,`,,` - Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale Summary In 1996 a survey was sent by the API Subcommittee on Inspection; Coke Drum Task Group, to companies operating coke drums in the United States and abroad This was the third survey of similar nature conducted by the API Fifty-four surveys were returned representing 17 different operating companies and a total of 145 drums The purpose of this survey was to collect data covering a broad range of issues including: `,,-`-`,,`,,`,`,,` - General information Design Operating Information Inspection Practices Deterioration Experience Repair Procedures Three of the six areas, Operation Information, Inspection Practices and Deterioration Experience were not covered in the first two surveys Additionally, this third survey asked more information in the other three areas as compared to the first two surveys Capstone Engineering Services, Inc was contracted by the American Petroleum Institute (API) to collect, tabulate and develop correlation’s with the data in an effort to increase safety and reliability of coke drum operation Findings (per Survey): General: 1) 20% of the surveys (12% of the drums) (41% of Companies) reported that they had experienced a fire 2) Not all through wall cracks resulted in fires 3) There were no reported incidents of a drum crack causing a fire that damaged adjacent equipment 4) 94% indicated a desire to have an API Recommended Practice Design: 5) New drum material selection has been towards increasing Chrome Moly alloy content 6) As observed in the 1968 Survey, no correlation between drum life and drum material was apparent 7) 40% indicated they had removable insulation around the skirt to aid in inspection of these locations Operation: 8) No correlation between drum cracking and fill cycle time was found 9) Drum operating parameters such as initial quench rate and proofing quench practice rather than metallurgy appears to have a greater influence on drum cracking Skirt Deterioration Experience: 10) Skirt cracking was reported by 78% of the surveys 11) 43% of these reported cracks propagated into the shell 12) 89% of the skirts with slots experienced cracking 13) Only 22% of the skirts without slots experienced cracking 14) In-line skirts accounted for 83% of the skirts that did not experience cracking v Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS Not for Resale 15) 16) 75% of the skirts without cracking were skirts that had flush ground welds 67% of the skirts without cracking were both in-line design and had flush ground welds 17) Skirts were replaced by 23% 18) Of the 23% that replaced skirts, recracking eventually occurred 43% of the time Shell Deterioration Experience: 19) First bulge appeared sooner than first through wall cracks 20) Shell bulging was reported by 57% 21) Shell cracking was reported by 57% 22) Of the drums that bulged, 87% also experienced cracks 23) Cracking without bulging was reported only by 6% 24) Circumferential cracking was found 97% of the time 25) Most cracks and bulges were located in courses 3, 4, and (course is at the bottom) 26) Roll bond cladding was used the most and had a slightly better success rate, however the data set for explosion bond and plug weld cladding was small Repair Procedures: 27) Shell repairs were performed from the OD by 26% 28) Of the 26% that performed OD repairs of ID cracking, 88% experienced recracking 29) Shell repairs were performed from the ID by 55% 30) Of the 55% that performed ID repairs, only 21% experienced recracking Inspection Procedures: 31) 32) The most common method of mapping bulges was manually as reported by 26 surveys Responses from 14 surveys reported using laser mapping techniques Considering drums four years and older: • • • 100% of the surveys indicated that some form of inspection was performed during shutdowns 40% indicated that they performed some inspection during operation Frequency of internal inspection varied from one year intervals to 10 year intervals with an average of years Future Survey Recommendations: 34)Given the complexity of the design and operation of coke drums, it is anticipated that there would be minimal value in performing another industry wide coke drum survey in 10 years 35)If a survey was performed in the future, it is recommended to selectively survey younger drums made of similar materials and experienced fewer variations in cycle time and operation vi Copyright American Petroleum Institute Provided by IHS under license with API No reproduction or networking permitted without license from IHS `,,-`-`,,`,,`,`,,` - Not for Resale