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

m.venkatesh@aecom.com

rob.cox@ipieca.org

please visit the IPIECA Booth - 9127