Calculating Aeration Flow and Pressure Requirements

1 Calculating Aeration Flow and Pressure RequirementsBrought to you by:For your free subscription, please visit rights are reserved. The contents of this publication may not be reproduced in whole or in part without consent of Smith Onandia Communications LLC. Smith Onandia Communications LLC does not assume and hereby disclaims any liability to any person for any loss or damage caused by errors or omissions in the material contained herein, regardless of whether such errors result from negligence, accident, or any other cause materials presented are educational. Each blower system is unique and must be evaluated on its own your free subscription, please visit About the SpeakerTom Jenkins, JenTechInc. President of JenTechInc. Has over 30 years of experience with Aeration blowers and blower controlsBrought to you by: Aeration BLOWER SELECTIONIT S ALL ABOUT THE BUBBLESWEBINAR THURSDAY, 5/26/20162:00 PM TO 2:30 PM ESTBLOWER & VACUUM BEST PRACTICES 1:35 PM4 TOPICS BASIC WASTEWATER TREATMENT PROCESS BLOWER FUNCTIONS BASICS OF DETERMINING air flow RATE BASICS OF DETERMINING DISCHARGE Pressure SUMMARY OF APPLICATION CONSIDERATIONS1:35 PM5 PROCESS BASICS1.

2 35 PM6 Primary ClarifierBar ScreensInflu en tRaw Wastew aterPrimary Sludg eto Digestio nAeration BasinSeco ndary ClarifierWaste Activated Slud ge (WAS) to Digestio nReturn Acti vated Slud ge (RAS) Ambient Ai rSeco ndary Effluentto Disin fectionor Addition al TreatmentBlowerMixed L iquorBacteria (Sl udge)Wastew aterO xygen(Settlin g Tank)(Settlin g Tank)Diffu sersPrimary TreatmentRemoves Insolubl e PollutantsSeco ndary TreamentSolu ble Pollu tants RemovedBy Microorganism MetabolismMicroorganisms Settl e as Sludg eAIR SUPPLIED TO Aeration BASINS HASMULTIPLE FUNCTIONS PROVIDE OXYGEN NEEDED FOR METABOLIZING ORGANIC COMPOUNDS PROVIDE OXYGEN NEEDED FOR CONVERTING AMMONIA (NH3) TO NITRATE (NO3) KEEP BASIN CONTENTS (MIXED LIQUOR) MIXED AND SOLIDS IN SUSPENSION MIN FLOW CFM/SQFTTYPICAL MAX air flow DICTATED BY DIFFUSER LIMITATIONS1:35 PM7A BLOWER S FUNCTION IS TO SUPPLY THE NEEDED air flow RATE TO THE BASINS THE MOST COMMON PROCESSES USE DIFFUSERS TO INTRODUCE AIR TO THE BOTTOM OF THE BASINS IT S ALL ABOUT THE BUBBLES!

3 1:35 PM8 DETERMINING air flow RATE REQUIRED air flow RATE IS USUALLY SPECIFIED AS SCFM LOOKS LIKE VOLUME FLOW RATE, BUT IS REALLY MASS FLOW RATE STANDARD CONDITIONS IN WASTEWATER USUALLY 68 F, PSIA, AND 36% RH THIS IS EQUIVALENT TO LB/FT31:35 PM9 DETERMINING air flow RATEICFM=SCFM 460+T528 Flow Rate ft3/minT=Temperature Fp= Pressure psia1:35 PM10 IF RELATIVE HUMIDITY IS IGNORED:DETERMINING air flow RATE NOTHING IN AN Aeration SYSTEM IS STEADY STATE DEMAND VARIES WITH TIME OF DAY, SEASON, WEATHER, OPERATION GREATEST VARIATION IS TIME OF DAY DIURNAL VARIATIONS1:35 PM11 DETERMINING air flow RATE NOTHING IN AN Aeration SYSTEM IS STEADY STATE DEMAND VARIES WITH TIME OF DAY, SEASON, WEATHER, OPERATION GREATEST VARIATION IS TIME OF DAY DIURNAL VARIATIONS1:35 PM12 DETERMINING air flow RATESCFM= mgdOTE (ppmBOD +ppmNH3 )SCFM= air flow Rate standard ft3/minOTE=Oxygen Transfer Efficiency, decimalppmBOD=parts per million Biochemical Oxygen DemandppmNH3=parts per million ammonia 1:35 PM13 FIELD OTE VARIES FROM TO PER FOOT OF SUBMERGENCE ( TO OTE/ft.)

4 NONE OF THE TERMS ARE STEADY STATEDETERMINING air flow RATE TURNDOWN FOR BLOWERS IS MORE IMPORTANT THAN EFFICIENCY NEEDED FOR PROCESS CONTROL NEEDED FOR ENERGY OPTIMIZATION TYPICALLY AT LEAST 5:1 (80%) TURNDOWN IS DESIRABLE1:35 PM14 Turndown%=qmax qminqmax 100 DETERMINING air flow RATE EPA REQUIRES STANDBY BLOWERS MUST HAVE FULL DESIGN air flow WITH LARGEST UNIT OUT OF SERVICE MOST BLOWERS CAN PROVIDE ABOUT 50% TURNDOWN EACH USE MULTIPLE SMALL BLOWERS INSTEAD OF TWO LARGER ONES THREE AT 50% OF DESIGN FLOW COMMON BUT NOT MY PREFERENCE I PREFER TWO AT 50% OF DESIGN FLOW AND TWO AT 25% OF DESIGN FLOW1:35 PM15 DETERMINING SYSTEM Pressure BLOWERS DO NOT PRODUCE Pressure THEY PRODUCE FLOW THE SYSTEM RESISTANCE TO THE FLOW CREATES THE Pressure BLOWERS WILL KEEP AIR MOVING UNTIL THE BACK Pressure EXCEEDS THE BLOWER S CAPABILITY CENTRIFUGAL BLOWERS WILL GO INTO SURGE NO FLOW PD (POSITIVE DISPLACEMENT) BLOWERS WILL OPEN RELIEF VALVE OR OVERLOAD MOTOR1:35 PM16 DETERMINING SYSTEM Pressure Pressure CONSISTS OF TWO PARTS STATIC Pressure FROM DIFFUSER SUBMERGENCE IS USUALLY 80% TO 90% OF TOTAL THE REST IS FRICTION FROM PIPE, FITTINGS, AND DIFFUSERS1:35 PM17 DETERMINING SYSTEM PRESSURE1.

5 35 PM18 Inlet Filter LossInlet Piping LossBlower Pressure RisePipe Friction Loss -2 0 2 4 8 10psig 6 Fitting Friction LossPipe Friction LossPipe Friction LossPipe Friction LossPipe Friction LossVelocity Head RegainRelease toAtmosphereValve Pressure DropVelocity Head RegainDETERMINING SYSTEM Pressure TO DETERMINE FLOW RATE BOTH BLOWER PERFORMANCE CURVE AND SYSTEM CURVE MUST BE PLOTTED THE INTERSECTION OF THE TWO CURVES IDENTIFIES THE FLOW RATE STATIC Pressure IS CONSTANT1:35 PM19psigstatic=submergence, SYSTEM Pressure TO DETERMINE FLOW RATE BOTH BLOWER PERFORMANCE CURVE AND SYSTEM CURVE MUST BE PLOTTED FRICTION IS TYPICALLY TO PSIG FRICTION IS PROPORTIONAL TO THE FLOW RATE SQUARED1:35 PM20 psigfriction=k q2 DETERMINING SYSTEM PRESSURE1:35 PM211002030405060708090100110% FLOW RATE, SCFM605070809010011012010020304050607080 901001106050708090100110120% Pressure , psigSystem Curve and Blower PerformanceCentrifugalPositive CurveStatic OF APPLICATION CONSIDERATIONS DETERMINE FLOW BASED ON PROCESS Requirements MAX AND MIN FLOW LIMITS REQUIRED TURNDOWN DETERMINE Pressure BASED ON SYSTEM GEOMETRY SUBMERGENCE AND FRICTION INCLUDE VARIATIONS IN AMBIENT CONDITIONS IN SELECTION1:35 PM22 For your free subscription, please visit About the SpeakerJohn Conover, Atlas Copco Sales Manager, Blowers & Low- Pressure Compressors, for Atlas Copco Has over 20 yearsof experience in Product Marketing and ManagementCOMBINED TECHNOLOGY SOLUTION ZS/ZBSCREW VS CENTRIFUGAL TECHNOLOGYZS ScrewZB Centrifugal EfficiencyGoodBestTurndownBestGoodReliab ilityBestBestPress RangeBestGoodMaintenanceGood BestZS Screw BlowerZB Centrifugal BlowerREAL WORLD EXAMPLE Max capacity required is 15,000 SCFM @ 8 PSIG.

6 Moderate temperature swing: Summer is 105F Winter is 22F Average is 60F 10:1 diurnal loadingSite in Pacific NorthwestTEMPERATURE EFFECT ON MASS FLOWMax FlowZSSummer4800ZS Winter5800 ZBSummer6250ZS Winter7500024681012141618200100020003000 400050006000700080009000 Pressure (PSIG)Flow (SCFM) Pressure vs. Mass FlowSIMULATED SYSTEM SCREW BLOWERSS ystemPropertyValueMinFlow~1500 SCFMMax Flow~15000 kW/100 CFM3 + 1 System (8 PSIG)SIMULATED SYSTEM CENTRIFUGAL BLOWERSS ystemPropertyValueMinFlow~2750 SCFMMax Flow~18700 kW/100 CFM3 + 1 System (8 PSIG)SIMULATED SYSTEM COMBINED TECHNOLOGY1 ZS + 2 ZB + (1 ZS Spare)SystemPropertyValueMinFlow~1200 SCFMMax Flow~17800 kW/100 CFMSIMULATED SYSTEM COMBINED TECHNOLOGYS ystemMin FlowMax FlowTurndownAvg. Power ScrewOnly120015000~ Only275018700~ ~ Comparison Depending on loading Requirements , combined system makes sense Assume 10:1 diurnal loading for 15000 SCFM max system Centrifugal only system can t turn down Screw only system is less efficient by ~10% Combined technology is best fit CONCLUSION System Requirements determine optimal solution Atlas Copco has the equipment to provide a variety of unique solutions By combining this equipment with the right control schemes, power savings can be significant Atlas Copco has the technical resources and knowledge to fit our technology to the applicationCombined SystemCOMMITTED , June 30, 2016 2:00 PM ESTR egisterfor free at: van Ormer, Air Power USAK eynote Speaker June 2016 Webinar:Measuring Flow: A Critical Component of any Compressed Air Management System Sponsored by.