Steam Powered Energy Conservation at Fort Worth s Village Creek WRF

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Mercy Morris
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, BCEE Johnson Controls, Inc. Andrew T. Cronberg, P.E. City of Fort Worth Alan Bush, P.

1 Steam Powered Energy Conservation at Fort Worth s Village Creek WRF Peter V. Cavagnaro, P.E., BCEE Johnson Controls, Inc. Andrew T. Cronberg, P.E. City of Fort Worth Alan Bush, P.E., BCEE AECOM Michigan WEA, 2013 Conference June 24, 2013

2 Village Creek Wastewater Reclamation Facility First Construction 1950 s Qdesign = 166 MGD Qaverage = 105 MGD Single Stage A/S w Nitrification Anaerobic Digestion of Wastewater Solids

3 The Project The project was delivered using the Energy Performance Contracting (PC) model Energy savings funded all improvements identified in this project Johnson Controls was the Energy Services Company (ESCO) for the project Engineering provided by AECOM, Freese & Nichols, Vic Weir Consulting, and CDM Smith 3

4 Costs & Benefits Project Cost $35 million Annual Utility Savings $2.56 million Annual O&M Impacts $0.24 million Total Annual Benefits $2.80 million Simple Payback 12.4 years 4

5 Project Drivers in 2007 City Wide Effort to Comply with State Legislation SB12 (2007) renewed in 2011 via SB898 Extended the SB5 Goal of reducing annual electricity consumption by 5% for 6 more years, from Cost-Effective Electricity-Based Energy-Efficiency Measures Legislation was for air quality improvements State Energy Conservation Office (SECO) Annual Reporting Requirement continues, with 2007 as the Baseline 5

6 Project Drivers A list of projects competing for limited capital dollars Control of operating budget The Water Department represented 47% of the City s energy expenditures 6

7 City of Fort Worth PC to Date Department Transportation & Public Works (6 Phases) Water (Village Creek WRF) Total Project Cost $34 million $35 million $69 million Reducing electric consumption 37% in over 100 City facilities $93 million in total savings guaranteed over the contract term Secured approx. $2 million in utility rebates 7

8 Village Creek Electric Utility In FY 2008 the City purchased $3.4M for electricity at Village Creek Total Demand averaged 7 to 8 MW Aeration Blowers Primary Effluent Pumps Other pumps & Odor Control Aeration Blowers the main consumer Three to four blowers operated at a time HP 2 to 3-1,000 HP

9 Goal a Net Zero Energy Village Creek Facility! 9

10 1 - Turn off electric motor blowers Pre-project: 1000 HP HP 10

11 2 Reduce flaring of digester gas 11

12 3 Recover Gas Turbine Waste Heat 12

13 Journey to Net Zero began in the 1960 s Digester Gas fueled Engine Blowers & Generators Some heat recovery for anaerobic digesters 13

14 and continued in 2002 In FY02, the City s wastewater plant began utilizing a biogas-fired turbine-generator system Provided about 50% the electricity needs Photo courtesy of Vic Weir Consulting, Inc. 14

Recovery FIM #3A: Codigestion 15 FIM #6E: HVAC Improvements FIM #3B: Linear

15 Journey to Net Zero Energy, Phase III FIM #6A: Aeration Control Improvements FIM #5: Anoxic Zones FIM #1: Aeration Diffusers FIM #4: SCADA System FIM #2: Heat Recovery FIM #3A: Codigestion 15 FIM #6E: HVAC Improvements FIM #3B: Linear Motion 15 Mixers FIM #6D: Pump Operation Improvements FIM #6H: Power Factor Correction

Recirculation, transfer and feed pumps (six total) PLC control

16 VCWRF Co-Digestion System Dedicated facility: Truck unloading pad 30,000 gal mix tank Two 8,000 gal batch tanks Recirculation, transfer and feed pumps (six total) PLC control feeds each digester once/hour Receiving up to 9 x 6,000 gal trucks / day 16

17 Anaerobic Digestion Improvements Type: Linear Motion Mixers No: Six (6) digesters - One (1) mixer per digester Power: 10 HP per mixer Hydro Disk: 7-ft diameter, 18-in travel, 30 cycles per min 18-inch vertical travel HYDRO DISK AT MID DEPTH 7-ft diam 90-ft diam digester 17

18 Linear Motion Mixer Scotch-yoke & cam mechanism LMM Drive 18

Waste Heat Recovery Waste Heat Recovery Heat Recovery Steam Generator (HRSG) on Turbine Exhaust generates steam Duct Burner The duct burner uses

19 Waste Heat Recovery Waste Heat Recovery Heat Recovery Steam Generator (HRSG) on Turbine Exhaust generates steam Duct Burner The duct burner uses digester gas to boost the temperature of the turbine exhaust. The higher temperature is needed to produce enough steam to power two steam turbines 19

20 Steam Turbine Powered Blowers 2 unused 1200 HP 31,000 cfm blowers Rehab d and equipped with steam turbine drivers 20

21 Aeration Infrastructure renewed New 9-in membrane diffusers PTFE coating Include a 10-year manufacturer material warranty 21

22 Anoxic Zones & Nitrate Rich Recycle 22

23 SCADA System Replacement Project included the replacement of the existing Johnson Yokogawa SCADA system with a new Emerson Ovation SCADA Distributed Control System 23

24 Fitting the HEAT RECOVERY UNIT pieces together UNUSED BLOWERS MOTOR DRIVEN BLOWERS ANAEROBIC DIGESTERS GAS TURBINE DRIVEN GENERATORS 1000 AERATION SYSTEM OVER 20 YEARS OLD HEX SOLIDS TO DEWATERING WASTE HEAT FROM TURBINE EXHAUST HEATS DIGESTERS 24 SCADA SYSTEM OVER 20 YEARS OLD

25 HEAT RECOVERY UNIT UNUSED BLOWERS MOTOR DRIVEN BLOWERS ANAEROBIC DIGESTERS HEX SOLIDS TO DEWATERING GAS TURBINE DRIVEN GENERATORS WASTE HEAT FROM TURBINE EXHAUST HEATS DIGESTERS 1000 AERATION BASINS DIFFUSERS REPLACED ANOXIC ZONES ADDED NEW SCADA SYSTEM 25

26 HEAT RECOVERY STEAM GENERATOR 1 - STEAM TURBINE DRIVEN BLOWER MOTOR DRIVEN BLOWERS 2250 CONDENSATE RETURN ANAEROBIC DIGESTERS CLEANED & ENHANCED MIXING HEX REDUCTION IN SOLIDS TO DEWATERING ADDITIONAL DG TO OPERATE EXISTING GAS TURBINE DRIVEN GENERATORS WASTE HEAT FROM CONDENSER HEATS DIGESTERS AERATION BASINS DIFFUSERS REPLACED ANOXIC ZONES ADDED NEW SCADA SYSTEM

27 HEAT RECOVERY STEAM GENERATOR 2 - STEAM TURBINE DRIVEN BLOWERS MOTOR DRIVEN BLOWERS 2250 ADDITIONAL DG TO OPERATE DUCT BURNER CONDENSATE RETURN HIGH STRENGTH WASTE RECEIVING ANAEROBIC DIGESTERS CLEANED & ENHANCED MIXING HEX REDUCTION IN SOLIDS TO DEWATERING ADDITIONAL DG TO OPERATE EXISTING GAS TURBINE DRIVEN GENERATORS WASTE HEAT FROM CONDENSERS HEATS DIGESTERS AERATION BASINS DIFFUSERS REPLACED ANOXIC ZONES ADDED NEW SCADA SYSTEM

28 CONSUMPTION (KWH) Performance to Date 9,000,000 8,000,000 Electric Consumption ( ) $500,000 $450,000 7,000,000 $400,000 6,000,000 5,000,000 4,000,000 3,000,000 $350,000 $300,000 $250,000 $200,000 $150,000 2,000,000 $100,000 1,000,000 $50,000 0 $0 TOTAL PURCHASED (kwh) TOTAL GENERATED (TG1 + TG2) TOTAL GENERATED DIESEL ENGINE GENERATORS SAVINGS

29 Acknowledgements Fort Worth Water Department Sebastian Fichera, REM Assistant Water Director Madelene Rafalko, P.E. Senior Professional Engineer Gary LaGassey Lead Operator Ana Pena, Ph.D., P.E. Jerry Pressley Luke Matus, I&C Jake Pena, I&C Ron Carlson, P.E. The men and women who constructed and who operate the facilities. Johnson Controls Team Harry Romine, P.E., C.E.M. Account Executive Dennis Gallagher Construction Manager Sarah Phillips, P.E. Project Development Engineer Velton Ellis Construction Superintendent Vic Weir Consulting, Inc. Vic Weir, P.E. Freese and Nichols, Inc. Ted Gay, P.E. Leonard Ripley, Ph.D., P.E. Clay Rahn, P.E. AECOM Randy Wodrich Gary Breitwisch, P.E. CDM Smith Dean Gorell Nate Mogaru

30 Thank you Peter V. Cavagnaro, P.E., BCEE Project Development Consultant Johnson Controls, Inc

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