Robert Cox, IPIECA, United Kingdom Mudumbai Venkatesh AECOM, USA Vice President Improving water...
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Transcript of Robert Cox, IPIECA, United Kingdom Mudumbai Venkatesh AECOM, USA Vice President Improving water...
Robert Cox, IPIECA, United Kingdom
Mudumbai Venkatesh
AECOM, USAVice President
Improving water management in refining operations: minimizing consumption and maximizing re-use
Forum 22 – Managing Water in Upstream and Downstream Operations
Who we are:
AECOM is an international engineering company operating worldwide specializing in professional, technical & management services including refinery water and wastewater treatment.
www.aecom.com
IPIECA is a global oil and gas industry association for environmental and social issues
www.ipieca.org
Outline of Presentation• Introduction
• Refinery Water Balance
• Raw Water uses in the Refinery
• Management of Wastewater
• Refinery Wastewater Treatment
• Water Reuse
• Zero Liquid Discharge
Introduction • Refineries use a significant amount of
water when compared to other industries
• Critical shortages of water in many parts of the world
• Refineries are trying to minimize water usage and maximize recycle/reuse
Refinery Water Balance
C.W. Supply
Process Units CoolingTowers
Boilers
WastewaterTreatment
SourWater
Stripper
Raw WaterTreatment
IX/RO
CrudeTanks
Raw Water
C.W. Return
Blowdown
Steam
BFW
Condensate ReturnBlowdown
Excess SSW
Makeup
Makeup
Evaporation & Drift
Steamlosses
Desalter Effluent
SourWater
StrippedSourWater
CrudeTankDrain
Waste
StormwaterExfiltrationInfiltration
Discharge
Raw Water Users in the Refinery• Process Water
Wash Water
• Boiler Feed Water - Makeup
• Cooling Water - Makeup
• Potable Water
• Fire Water
• Utility Water
Wastewater - Desalter• Desalter - First unit operation - used to wash
naturally occurring salts in the crude to protect downstream equipment
• Wash water - 5 to 8% of crude throughput• Drilling muds are also periodically purged• Operating pH in the Desalter should be 7 or lower
to prevent formation of excessive emulsions• Results on discharges of excessive hydrocarbons -
loss of crude, slop creation
Wastewater - Desalter • Desalter Wash Water Sources
Fresh waterBoiler Feed WaterCrude Tower OverheadVacuum tower OverheadStripped Sour Water
• Stripped Sour Water is best choice - results in significant savings in water usage
Wastewater - Sour Water• Sour Water - Stripping Steam condenses and
absorbs H2S and NH3
• High Performance Strippers - <1ppm H2S and <30ppm NH3
• Stripped sour water is an ideal candidate for recycle within the refinery
• Phenolic Sour Water - Cat Crackers and Cokers
• Non-Phenolic Sour Water-Other producers
Wastewater - Sour Water• Stripped phenolic SW should be
processed in a separate stripper and preferentially used for Desalter makeup
• Up to 90% of phenol will be extracted into the crude - lowering phenol load to WWT
• Remaining stripped SW should also be used in the Deslater if possible - excess should be discharged to WWT
Wastewater Tank Bottom Draws
• Crude Tanks, Gasoline Tanks, Slop Tanks
• Crude Tank Draw - example
Crude Tank
Interface Level
Indicator BermBermDrain Valve
Sump
To WWT
Pump
Grade
L I
Water to WWT
Sludge to Treatment
Oil to slops
Tank
Wastewater - Spent Caustic• Hydrocarbon product streams are washed
with caustic to remove acidic compounds such as sulfides, organic acids, etc
• Spent caustic is purged from the system• Phenolic spent caustic can be sent offsite
for recovery (high odour stream)• Sulfidic SC can be treated in the WWTP• High TAN crudes produce naphthenic spent
caustic - toxic to biological systems
Refinery Wastewater Treatment
• Wastewater Segregation• High TDS - Desalter Effluent, Tank BS&W, Spent
Caustic• Low TDS - Stripped Sour Water, Storm water,
Miscellaneous WW• Two parallel trains of treatment
Sludge
EqualizationSecondaryOil/Water
Separation
PrimaryOil/Water
Separation
Biological Treatment Clarification
Tertiary Treatment
EffluentRefineryWastewater
Sludge
Oil toSlop
Oil toSlop
Water Reuse • Potential Users - Desalter Makeup, Coker quench
water, cutting water, Flare seal water, FCC scrubber, Hydrotreaters, BFW and Cooling Tower Makeup, Potable water, Fire Water, Utility water
• Reuse non-contaminated storm water• Treated refinery wastewater• Treated municipal wastewater from outside sources
Technologies for Upgrade• Suitability of technology is site specific and
should be evaluated case-by-case
• Criteria for Evaluation– Prior application in refineries for water reuse– Ability to consistently achieve product specification– Operability & Flexibility– Capital & Operating Costs– Plot Space Requirements
Water Reuse Technologies - Ion Exchange
AnionBed
CationBed
FeedWater
RegenerationReject
RegenerationReject
ToMakeup
Water Reuse Technologies -UF/RO
Refinery WWTincl.
Sand Filter
Activatedcarbon
Ultra-Filtration
ReverseOsmosis
pHadjust
pHadjust
Waterto recycle
WW
RejectBackwash
Water Reuse Technologies - UF/EDR
Refinery WWTincl.
Sand Filter
Activatedcarbon
EDR
Waterto recycle
WW
Ultra-Filtration
Electric Current
RejectBackwash
Water Reuse Technologies - ZLD
Activatedcarbon
Ultra-Filtration
ReverseOsmosis
pHadjust
pHadjust
TreatedWastewater
RejectBackwash
Permeateto Recycle
Steam
Evaporation/Crystallization
Salt Crystalsto Disposal
Document is available at www.ipieca.org
Thank you for your attention
Questions???
Contact Information
please visit the IPIECA Booth - 9127