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Achieving On-stream Reliability At TESORO’S Mandan FCC Unit
Presented byHarvey McQuiston, FCC Program Director, Shaw E & C
Galveston, TX May 3-6, 2011
History
• The FCC unit is an Exxon Model IV originally commissioned in 1954
• Tesoro acquired Mandan, North Dakota Refinery in 2001• Tesoro revamped the FCC unit to upgrade technology and
improve reliability
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improve reliability• After the revamp the FCC unit ran continuously without a
major outage• The next scheduled turnaround revealed that only nominal
routine maintenance was required
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Unit Description (Pre-Revamp)
• Cat feed is reduced crude (no VDU)• 23-26,000 bpsd feed• 4 Bete nozzles (feed & HCO)• Internal rough cut cyclone & quench
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• Partial CO burn (5% CO) 1330-1360◌ ْF
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Original Design
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Operating Issues
• Poor conversion, high dry gas and bottoms• Slurry circuit fouling issues• On-line maintenance difficult due to long, harsh winters• FCC reliability impacts crude unit as both units are heat
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integrated
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Revamp Objectives
• Improve conversion• Minimize dry gas• Maximize C3/C4 yields (summer)• Maximize octane barrels
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• Improve reliability to minimize unscheduled shutdowns• Reduce routine maintenance
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Technology Upgrades
• New external vertical riser with longer residence time• New Shaw feed injection nozzles• New rough cut cyclone (external)• Installed reactor vapor quench
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• Longer catalyst stripper (more stages)
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Demolition Plan
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Revamped Unit
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Revamped Unit
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Revamped Unit
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Layout of Revamped Unit
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Revamp Project Schedule
• Overall schedule – 14 months• Basic engineering – 10 weeks• Detail engineering started week 5
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• Full project approval by week 15• All equipment delivered within 12 months• Turnaround duration 33 days (oil out to oil in)
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Revamp Project Schedule
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Basic Engineering Design Package
Prelim. Equipment Specifications
Project Cost Estimate
Months
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Owner Project Approval
Detail Engineering (Pre-Approval)
Detail Engineering (Post-Approval)
Procurement
Equipment Deliveries
Pre-Turnaround Construction
Construction Turnaround
Revamp Construction Issues
• Needed “Fast-Track” to finish by winter• Pre-turnaround construction
– External riser– Rough cut cyclone
• Turnaround construction
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– Replaced reactor top head and secondary cyclones– Replaced stripper including new stages
• Duration 33 days – oil out to oil in
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Pre and Post Revamp Data
Data at 990F ROT
100%
120%
140%
d Va
lues 8% Reduction
21% Increase
No Change 62% Reduction
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0%
20%
40%
60%
80%
SAOG Cat Gasoline MCCO DCO
% o
f Pre
turn
arou
nd
Vapor Quench
• Required sealing• 7% reduction in dry gas• Regenerator temperature dropped 16◌ ْF• Helped cool reactor overhead line & main column bottoms
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Additional Improvements
• Slurry gravity 18 API → 0 API• Liquid yield up 3.3 vol%• On-stream maintenance of slurry pumps and exchangers
dramatically reduced
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• More slide valve ∆ P, smoother operation• Easier startup (hours versus 1½ days)
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Unscheduled Outages Avoided
• Blockage around spent cat trash guard cleared by a controlled reversal pulse of the spent cat standpipe
• No prolonged outage/thermal cycle occurred until the regularly scheduled maintenance turnaround
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Turnaround Repairs Minimal
• Reactor secondary cyclone repair• Refractory damage in cross-over duct from rough-cut
cyclone to reactor• Typical coke deposits on reactor wall, roof of secondary
cyclones and on backside of secondary cyclone gas tube
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cyclones and on backside of secondary cyclone gas tube• Minimal repairs to feed injectors, some injector tips starting
to show wear• Turnaround period and subsequent startup went smoothly
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Feed Injector Target Bolt Inspection
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Feed Injector Orifice
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Feed Injector Tip Inspection
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Riser – Looking Down to Feed Injectors
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Stripper - Bottom Baffle and Steam Ring
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Rough-Cut Cyclone Dipleg Outlet
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Key Factors for On-Stream Reliability
• Proper design and installation of new components for anticipated throughput and operating conditions
• Maintaining throughput and operating conditions within the design parameters Proper design/specification and installation of refractory
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• Proper design/specification, and installation of refractory materials and anchoring systems
• Minimizing thermal cycles by avoiding unnecessary outages
• Proper on-stream maintenance• Maintaining well-trained, experienced operating personnel
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Conclusion
• A Model IV was easily revamped to significantly improve conversion and yield selectivity (21% more gasoline)
• A fast track project (14 months) was achieved utilizing licensor/contractor single point responsibilityRevamp downtime was reduced by maximizing pre
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• Revamp downtime was reduced by maximizing pre-turnaround activities (33 days oil out to oil in)
• On-stream reliability was successfully achieved by making the proper process, mechanical, and operational improvements
• Minimizing unscheduled outages reduced the need for repairs to only routine maintenance during the next scheduled turnaround
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Any Questions?Harvey McQuiston
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