Robert Cox, IPIECA, United Kingdom Improving water management in refining operations: minimizing consumption and maximizing re-use Mudumbai Venkatesh Vice President AECOM, USA Robert Cox, IPIECA, United Kingdom 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 Critical shortages of water in many parts of the world 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

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 water Boiler Feed Water Crude Tower Overhead Vacuum tower Overhead Stripped 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

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

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

Water Reuse Technologies -UF/RO

Water Reuse Technologies - UF/EDR

Water Reuse Technologies - ZLD

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