co-generation: today’s reality
DESCRIPTION
Co-Generation: Today’s Reality. Larry McFall Plant Operations Manager Rock River Water Reclamation District Rockford, IL [email protected]. Introduction. 1,100 Miles of Sewer 33.9 MGD Influent 7 Communities 75,000 Accounts 240,000 Connected Population. Water Treatment. Primary - PowerPoint PPT PresentationTRANSCRIPT
Co-Generation: Today’s Reality
Larry McFall
Plant Operations Manager
Rock River Water Reclamation District
Rockford, IL
Introduction
• 1,100 Miles of Sewer
• 33.9 MGD Influent
• 7 Communities
• 75,000 Accounts
• 240,000 Connected Population
Water Treatment
• Primary– Screening, Grit, & Primary Clarification
• Aerobic Activated Sludge– Final Clarification
• Disinfection
Energy Introduction
• Raw Materials
– Waste Organic Material in Wastewater (Feedstock)
• Treatment & Utilization Process
– Anaerobic Digester
– Electrical Generators
• Products
– Electricity
– Heat
– Biosolids (Fertilizer)
Waste Organic Feedstock
• Waste Organic Material in Wastewater– Raw Sludge
• Primary Clarifiers• Gravity Thickener (5.4% Solids)
– Waste Activated Sludge• Gravity Belt Thickener (6.6% Solids)
– Skimmed Fats, Oils & Grease (FOG)
Treatment & Utilization Process
• Anaerobic Digestion– Controlled Conditions– Utilize Waste Heat from Electrical Generators
• Condition Biogas– Remove Moisture– Remove Contaminants
• Electrical Generators– Produce Electricity– Recover Waste Heat
Anaerobic Digestion
• Controlled Conditions– Mesophilic Digestion (100º F or 38º C)– Complete Mix
• Biological Process– Acid Formers– Methanogenic Bacteria
Anaerobic Digestion
• Biogas– Methane, Carbon Dioxide, Nitrogen– Water Vapor– Hydrogen Sulfide, Siloxanes, Hydrogen
• Biosolids– Fixed & Stabilized Organic Solids– Nutrients & Micro Nutrients
Anaerobic Digestion
Biogas
• Biogas Conditioning– 1st Stage Hydrogen Sulfide Removal
• Ferric Chloride Addition to Digesters
– 1st Stage Moisture Removal• Refrigeration to 45º F Dewpoint
– 2nd Stage Moisture Removal• Refrigeration to 34º F Dewpoint• Coalescing Filter
Biogas
• Biogas Conditioning Continued– Pressure Boost– Mixed Carbon Bed
• Siloxane Removal• 2nd Stage Hydrogen Sulfide Removal
– Reheat Gas
Biogas
Siloxane + Oxygen Silicone Dioxide
(Sand)
Biogas
• Siloxanes as Si, mg/M3
– Maximum 46.6– Minimum 2.7– Average 13.4– Major Constituent
• D5 (Decamethylcyclopentasiloxane)
Biogas
0
10
20
30
40
50
60
70
80
90
1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
East
West
North
Generators
• 3 Generators @ 1 MW each
• Fuel– Biogas– Natural Gas
• Heat Recovery– Jacket Water– Exhaust Gases
Generators
• Operation and Maintenance– Laboratory
• Gas Analysis• Engine Oil Analysis
– Routine Maintenance• Change Oil and Filters• Gap or Change Spark Plugs• Rectifiers
• Add Generator Picture
Investment
• Capital– $2,000 per kW of Electricity
• Operation & Maintenance– $0.01 per kWhr
Bio-Products
• Electricity– 410 MWhr/Month– $33,000/Month
• Heat– 4.5 Million BTU/hr each Engine– Process Heat for Digesters– Building Heat
Bio-Products
• Biosolids (Fertilizer)– Apply 17,000 wet Tons Annually– 1,700 Acres of Farmland Annually
• Corn• Wheat• Soybeans
– Fertilizer Value of $85/acre
Future Improvements
• Co-Digestion of High Strength Wastes– Fats, Grease and Oils Direct from Source– Bio-diesel Byproducts– Algae– High Strength Food Production Wastes
• Utilization of Waste Heat– Cooling
Co-Generation: Today’s Reality
Questions?
Co-Generation: Today’s Reality
Larry McFall
Plant Operations Manager
Rock River Water Reclamation District
Rockford, IL