new crude heater for better better efficiency, …
TRANSCRIPT
NEW CRUDE HEATER FOR
BETTER EFFICIENCY,
RELIABILITY & ENVIRONMENTAL
PERFORMANCERAJ GHETIA
TECHNICAL SERVICES DEPARTMENT
THANGARAJ RAJU
PLANT ENGINEERING DEPARTMENT
BAPCO, BAHRAIN
NEW CRUDE HEATER FOR BETTER
EFFICIENCY, RELIABILITY & ENVIRONMENTAL PERFORMANCE
24 October 2018
RAJ GHETIA
TECHNICAL SERVICES DEPT.
THANGARAJ RAJU
PLANT ENGINEERING DEPT.
Agenda
• Introduction
• Present Situation
• Proposal
• Project Objectives
• Economic Justification
• Challenges
• Project aspects - Overview
• Project Execution Plan
• Project work and challenges
• Concluding Remarks
2
Introduction
• Refinery started in 1936 at 22 MBPD, in operation for more than 80 years
• Current crude processing capacity is 267 MBPD
• 5 Crude Units & 5 Vacuum Units
• Conversion units: HVGO hydrocracker, FCCU, Lube Base Oil, Visbreaker and Platformer
• Fired heaters - largest consumers of energy, similar to other refineries
• Efficiency and performance improvements can deliver substantial energy savings and improve profitability
3
Background4
• Bapco refinery has 45 fired heaters ages between 5 and 82 years.
• Extensive operating experience with fired heaters and their optimisation and troubleshooting
• Post Bapco Modernisation Program (BMP) - many old and inefficient process units will be decommissioned
• No. 5 Crude Unit (5CDU) will remain
• Three parallel fired heaters - built in 1943 (75 years old)
• Initiative launched in 2015 to replace these 3 heaters
Present Situation - Existing 5CDU Heaters
• Heater type - natural draft, cabin type with two radiant cells and a common overhead convection section.
• Low efficiency - 60%, flue gas >1000°F & Excess O2 - 6.5%
• High coking rate →intermediate shutdowns to decoke tubes
• Low operating flexibility - turndown 85%
• Poor control of draft and excess O2
• High maintenance cost
• Poor operability - tube configuration
• NOx emissions sometimes exceed limit
• Burners cannot fire low heating value gas
5
Present Situation (cont’d)
Why do we have these issues?• Insufficient tube heat transfer area & no finned tubes in convection section
✓ Very high average radiant heat flux - 18,000 vs 12,000 Btu/hr-ft2 (Best Practice)
• Tube pass configuration - cannot measure flow split between the passes
• Insufficient instrumentation to monitor, control, optimize performance
✓ No online excess oxygen/combustibles measurement
✓ No automatic damper control mechanism
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Present Situation (cont’d)
• Burner type – dual head premix Ramshorn
✓ High number - 60 total
✓ Not designed to fire low heating value gas
✓ Alignment concern
✓ Fouling issues
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Ramshorn Burner
Present Situation (cont’d)
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Refractory fall-out
Deposits/scale
from burner
pipe
Inside the air-fuel mixer
Proposal
• Build a single heater to replace the existing 3 heaters
✓ Vertical cylindrical natural draft - minimise cost & space requirement
✓ Design radiant heat flux - 12,000 Btu/hr-ft2
✓ Efficiency - 90%
✓ Low NOx burners - 12 in total
✓ Improved turndown - 50%
✓ Instrumentation - O2 & combustibles analysers, draft , TI’s
✓ Remote damper control
✓ Burner flexibility to fire gases, individually or in combination, of varying heating values (700 to 1750 Btu/Scf)
✓ Access doors to allow cleaning of convection section tubes
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Project Objectives
• Significantly increase efficiency and thus, profitability
✓ Energy saving - 60 MMBtu/hr
• Increase operational availability
✓ 6 year continuous run
• Reduce maintenance
✓ No tube replacement and much lower burner count
• Improve environmental performance (reduce CO2 & NOx)
✓ CO2 reduction 45 tons/day
✓ NOx – guaranteed <100 mg/Nm3 : predicted < 60mg/Nm3
• Enhance operability and control
✓ State-of-the-art instrumentation
✓ Improved safety with SIL rated ESD system
• Meet latest standards and industry best practices
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Economic Justification11
• Pre-BMP:
✓ Fuel gas saving due to heater efficiency improvement
▪ Heater fires FCCU/Visbreaker off-gases
✓ Heater runs for a full 6 year T&I cycle
▪ Saves one decoke shutdown cost & loss of crude throughput
• Post-BMP:
✓ Heater fires 100% low LHV Khuff gas (FCCU/Visbreaker decommissioned)
✓ Higher benefit after BMP due to recovery of C3, C4 & Naphtha which had to be burned in the old heaters to maintain minimum LHV
✓ Heater runs for a full 6 year T&I cycle
▪ Saves two decoke shutdown cost & loss of crude throughput
✓ IIR - 15% with simple payback of 6 years
Challenges
• Selection of location for new heater
✓ Brown field project
✓ Compliance with Bapco safety standard
• Requirement to replace existing crude booster pump
• Providing bypass around Crude/Atmospheric Resid exchanger
• Execution constraints
✓ Many lines - rerouted to create space for new pipelines and supports
✓ 2800 people working simultaneously in congested plant area
✓ Hot tapping 8”x 8” planned for 550# superheated steam line
✓ Demolition of existing 3 heaters (with unit in operation)
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Empowering Progress
Engineering and execution
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Thangaraj Raju
Plant Engineering Department
Project Aspect - Overview
• 5CDU Heaters replacement project followed Chevron Project Development Evaluation Process (CPDEP)
• Scope of project includes:
✓ Vertical cylindrical heater 32 ft diameter, 213 ft height, with 12 burners
✓ CFD Analysis to ensure acceptable firing pattern
✓ Fuel gas knockout drum followed by coalescer & pilot gas knockout drum
✓ Two crude booster pumps
✓ Demolition of existing 3 heaters (with unit onstream)
• Features:
✓ Modular construction of radiant, convection & stack assemblies
✓ Ex-situ refractory dryout
• Front End Engineering Design(FEED) - Engineers India Ltd (EIL)
• Engineering, Procurement & Construction (EPC) - JGC Gulf International Ltd
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Project Execution Plan
• Project schedule - 20 months
• 4 Phases of execution :
✓ Before 5CDU T&I (unit onstream) - 5%
✓ During 5CDU T&I (Nov 2017) - 30%
✓ After 5CDU T&I (unit onstream) - 60%
✓ Short shutdown for commissioning - 5%
• Challenging job due to brownfield project in congested area
• Jobs provisionally planned before unit T&I could not be done due to safety
concerns
15
Project Work - During T&I
• Jobs carried out during 22 days of T&I :
✓ Civil foundation supports for pipe rack & pipe supports (100 nos)
✓ Installation of pipe rack 50 metres and its pipe supports
✓ Piping tie-ins >100 nos
✓ Installation of pipelines ~1000 metres on new pipe rack/supports
✓ Hydrotesting, painting & insulation
✓ Welding of reinforcements for fireproofing for pipe rack & pipe supports
✓ Demolition of work station
✓ Re-location of guy wires on existing heater stack
✓ Replacement of UPS
✓ Modification of 2.3KV switch-gear for power supply to new booster pump motor
✓ Underground survey and trial pit for booster pump foundations
16
Project Work - During T&I (cont’d) 17
Work In Progress - During 5CDU T&I18
Challenges faced during T&I
• Integration of project schedule with shutdown maintenance T&I schedule
• Difficulty in welding new and old alloy steel pipelines due to magnetization
• Sharing of work space, resources and cranes with Maintenance Department
• Plan integration
• Alternative technique of Phased Array Ultrasonic Testing (PAUT) in place of radiography
• Additional stress relieving machines to cater for 200 alloy steel & NACE weld joints
• Some H2S emission and continuous release of oily water during excavation for foundation of pipe supports
• All the T&I related work for new heater were done with zero incidents
19
EPC Work after T&I
• 30%, 60% & 90% 3D Model review
• HAZOP & SIL study
• Heater vendor package finalized and fabrication is in progress
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• Crude booster pump design review due to NPSH issues and relocation of pumps
• Coalescer design modified for maintenance work
Concluding Remarks
• Engineering and T&I activities done safely and successfully without incidents
• Now we need to safely install and commission the new heater on-schedule to meet the key objectives of improving Efficiency, Reliability & Environmental performance
❑ Key Success Factors
✓ Technically strong, experienced, aligned and motivated in-house multidisciplinary team
✓ Concept developed in-house
✓ Vital to involve the right people in the evaluation and decision-making process
✓ Close working relationship with the contractors and vendors
✓ Alignment of Bapco - Project / Maintenance teams and EPC/sub-contractor teams in completing jobs within stipulated time
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THANK YOU