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Zero Liquid Discharge at MacKay River Gary Giesbrecht - February 13, 2007 Why ZLD? Number of disposal wells available: zero Cost of 3rd party disposal: $100 - $150 / m3 Environmental Considerations Water balance improves More solid waste Water & Salt Configuration Produced Fluids BFW 77% Prod’n Trt Steam Plant Inj Stm Separator Water Trt Drive Steam Flash Drum 1/3 Dry Salt ZLD 2/3 ZLD Process Flows Return Condensate Drive Steam Air Cooled Condensers Forced Circulation Crystallizer ZLD Feed Saturated brine 850 t/d Vertical Falling Film Evaporator Filter Dry Salt 42 t/d dry Crystallizer Evaporator Air Cooled Condensers LP Steam Supply Injection Steam LP Drive Steam HP Wet Steam LV LV PV To ZLD To WTP SG Feedwater Cooling Glycol The Good News Operating at > 100% of design rate No fouling of heat transfer surfaces or elsewhere No sign of SCC in 6% Mo Silicone based defoamers effective but expensive Issues, Challenges and Valuable Learning Opportunities Water Soluble Organics (WSO) extracted from bitumen highly water soluble non volatile at OTSG conditions Therefore: non volatile at ZLD conditions accumulate in Crystallizer purge as moisture in salt cake WSO Accumulation Increased viscosity of crystallizer liquor causes poor filterability complex filter design didn’t help Decreased filter throughput increased TSS accumulation in crystallizer denser, more abrasive slurry Abrasive Slurry Metal loss at: vortex breaker vapour body (incl diaphragms) But not: pump/piping heat exchanger Metallurgy 254SMO AL6XN Responses “Wallpaper” vapour body with new metal Rebuild vortex breaker Derate vapour body DP Keep crystallizer TSS (mostly) in spec Reduce circulation rate Short term: Purge and dispose of liquids Long term: Eliminate filtrate recycle Metal loss rate decreased to zero Capacity Issues Feedwater TDS 8000 mg/L target → contract maximum Wet steam quality 80% → 77% Landfill leachate intermittently high Produced water TDS might be higher than design, obscured by carryover in steam Need catch up capacity ZLD Expansion/Upgrade Return Condensate Drive Steam MVC Crystallizer ZLD Feed 1700 t/d New Evaporator Exhaust Evaporator Saturated brine Gas Gas fired rotary drier Dry Salt 80 t/d dry Filter New Existing Foam Issues Currently don’t have a vapour compressor TDS upset only More stringent control with MVC Foam carryover can start quickly and empty the evaporator in minutes. Evaporator Configuration Condenser Drive Steam Condensate LT LT Distillate Sump DT Evaporator Level Upset @ 1h0m0s 05/09/25 23:15:57 05/09/26 00:15:57 100.00 100.00 30.00 Distillate 1.20 Tank Level 100.00 15.00 Feed FV Position Sump Level 0.00 0.00 Steam Fluid 0.00 Outlet 1.00 Flow Density 0.00 Flow 0.00 ** #1 (A) M08LIC365B.PIDA.PV 05/09/26 00:15:57 42.42 % (Avg @1 Min) EVAP/CDSR ** #2 (A) M08LIC450B.PIDA.PV 05/09/26 00:16:33 39.91 % (Raw) EVAP COND TANK ** #3 (A) M08FIC375.PIDA.PV 05/09/26 00:16:33 7.95 M3/HR (Raw) EVAP/CDSR STM IN (M3/H ** #4 (A) M08DIC366B.PIDA.PV 05/09/26 00:16:33 1.05 SG (Raw) EVAP/CDSR ** #5 (A) M08LIC365B.PIDA.OP 05/09/26 00:16:33 51.36 % (Raw) EVAP/CDSR ** #6 (A) M08FIC366.PIDA.PV 05/09/26 00:16:33 4.53 M3/HR (Raw) EVAP/CDSR OUT (M3/H CW Risk of foam remains Additional sensors in MVC evaporator Silicone antifoam effective Need base dose plus upset dose Hydrostatic level/density measurement may not be the best Prevention will become essential for protection of vapour compressor Solid Waste Management Meets Class II landfill criteria no free liquids < 2% oil & grease no hazardous leachate Project Landfill on lease add/close cells every few years started with separate salt & lime sludge cells now co-dispose both solid wastes Waste Salt Filtered Saltcake Rotary Drier Product Path Forward MR1 ZLD expansion starts up Q2 2007 MRX configuration very similar MVC evaporation Steam drive crystallizer Gas fired drier Ample capacity Questions?
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