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Exhibit MSD 73J - SMP TM 11
DRAFT BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) Technical Memorandum No. 11: Energy Recovery B&V PROJECT NO. 401975 PREPARED FOR Metropolitan St. Louis Sewer District 3 MARCH 2020 © B l a c k & V e a t c h H o l d i n g C o m p a n y 2 0 1 7. A l l r i g h t s r e s e r v e d . Exhibit MSD 73J Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Table of Contents i Table of Contents 1.0 Purpose and Scope .............................................................................................................................. 1-1 2.0 Lemay WWTF ........................................................................................................................................ 2-1 2.1 Background ............................................................................................................................................ 2-1 2.1.1 FBI Sizing and Loading Criteria ................................................................................... 2-1 2.1.2 Ameren Energy Incentives ............................................................................................ 2-1 2.1.3 Past Evaluations ................................................................................................................ 2-2 2.2 Building Heating ................................................................................................................................... 2-4 2.2.1 Existing Steam System .................................................................................................... 2-4 2.2.2 Building Heating Alternatives ...................................................................................... 2-7 2.2.3 Costs ....................................................................................................................................... 2-9 2.2.4 Non-Economic Criteria ................................................................................................. 2-11 2.2.5 Evaluation and Recommendation ............................................................................ 2-12 2.3 Electricity Generation ...................................................................................................................... 2-12 2.3.1 Electricity Generation Facility ................................................................................... 2-12 2.3.2 Costs ..................................................................................................................................... 2-14 2.3.3 Non-Economic Criteria ................................................................................................. 2-16 2.3.4 Evaluation and Recommendation ............................................................................ 2-16 3.0 Bissell Point WWTF ............................................................................................................................ 3-1 3.1 Background ............................................................................................................................................ 3-1 3.1.1 FBI Sizing and Loading Criteria ................................................................................... 3-1 3.1.2 Past Evaluations ................................................................................................................ 3-1 3.2 Electricity Production ........................................................................................................................ 3-4 3.2.1 Electricity Generation Facility ..................................................................................... 3-4 3.2.2 Costs ....................................................................................................................................... 3-5 3.2.3 Non-Economic Criteria ................................................................................................... 3-6 3.2.4 Evaluation and Recommendation .............................................................................. 3-6 3.3 Sale of Steam to Proctor & Gamble ............................................................................................... 3-6 3.3.1 Steam Generation Facility ............................................................................................. 3-6 3.3.2 Costs ....................................................................................................................................... 3-8 3.3.3 Non-Economic Criteria ................................................................................................... 3-9 3.3.4 Evaluation and Recommendation .............................................................................. 3-9 LIST OF TABLES Table 2-1 Lemay FBI Design Criteria ................................................................................................................ 2-1 Table 2-2 SMP (2010) TM2 Lemay Energy Recovery Alternative Design Criteria ....................... 2-2 Table 2-3 SMP (2010) TM2 Lemay Opinions of Costs, Savings, and Life Cycle Costs .................. 2-3 Table 2-4 Existing Steam System Design Criteria ....................................................................................... 2-5 Table 2-5 A1 ST-WHB, Steam Heating – FBI WHB Design Criteria ...................................................... 2-7 Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Table of Contents ii Table 2-6 A2 ST-NGB, Steam Heating – NG Boilers Design Criteria .................................................... 2-8 Table 2-7 A3 NG-SYS, Direct Fired NG Heating Design Criteria ............................................................ 2-9 Table 2-8 Lemay Building Heating Alternatives OPPC ........................................................................... 2-10 Table 2-9 Lemay Building Heating Alternatives Annual Differential Operating Costs .............. 2-11 Table 2-10 Lemay Building Heating Alternatives Present Worth Costs ............................................ 2-11 Table 2-11 Lemay Building Heating Alternatives Present Worth Costs ............................................ 2-11 Table 2-12 Lemay Electricity Generation Design Criteria ........................................................................ 2-13 Table 2-13 Lemay Electricity Production Alternative OPPC ................................................................... 2-14 Table 2-14 Lemay Electricity Generation Annual Differential Operating Costs ............................. 2-15 Table 2-15 Lemay Electricity Generation Alternative Present Worth Costs .................................... 2-16 Table 2-16 Lemay Electricity Generation Advantages and Disadvantage ......................................... 2-16 Table 3-1 Bissell Point FBI Design Criteria .................................................................................................... 3-1 Table 3-2 SMP (2010) TM1 Bissell Point Sale of Medium Pressure Steam Alternative Design Criteria....................................................................................................................................... 3-2 Table 3-3 SMP (2010) TM1 Bissell Point Power Generation Alternative Design Criteria ...................................................................................................................................................... 3-2 Table 3-4 SMP (2010) TM1 Bissell Point Opinions of Costs, Savings, and Life Cycle Costs .......................................................................................................................................................... 3-4 Table 3-5 Bissell Point Electricity Generation Annual Differential Operating Costs .................... 3-5 Table 3-6 Bissell Point Electricity Generation Alternative Present Worth Costs .......................... 3-6 Table 3-7 Bissell Electricity Generation Advantages and Disadvantage ........................................... 3-6 Table 3-8 Bissell Point Sale of Steam Design Criteria ................................................................................ 3-7 Table 3-9 Bissell Sale of Steam Alternative OPPC ....................................................................................... 3-8 Table 3-10 Bissell Point Sale of Steam Annual Differential Operating Costs ..................................... 3-9 Table 3-11 Bissell Point Sale of Steam Alternative Present Worth Costs ............................................ 3-9 Table 3-12 Bissell Point Sale of Steam Alternative Advantages and Disadvantage ......................... 3-9 LIST OF FIGURES Figure 2-1 Existing Steam Heating System ...................................................................................................... 2-6 Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Purpose and Scope 1-1 1.0 Purpose and Scope Waste heat recovery systems from fluidized bed incinerator (FBI) exhaust gas can provide substantial amounts of energy for use at treatment facilities, reducing power costs and non- renewable energy usage. For systems with electricity generation, often enough power can be produced to operate the FBI system with excess power available for other uses. However, waste heat recovery can also add significant capital costs as well as operating and maintenance effort. The purpose of this memorandum is to evaluate whether it is beneficial to include energy recovery from the FBI systems for building heat or electricity generation in the Bissell Point and Lemay Wastewater Treatment Facilities (WWTFs) Fluidized Bed Incinerators project. This memorandum includes sections covering: A review of past energy recovery evaluations A summary of the design basis for heat recovery Building Heat Replacement (Lemay) ● For evaluation of supplying building heat from energy recovery of FBI exhaust gas at the Lemay WWTF: a review of the existing heating system, identification of suitable heating alternatives, development of criteria for alternatives, and evaluation of economic and non- economic criteria Electricity Production (Bissell Point and Lemay) ● For evaluation of electricity production from energy recovery of FBI exhaust gas at the Lemay and Bissell Point WWTFs: identification of suitable power generation alternatives, development of criteria, and evaluation of economic and non-economic criteria Steam Production (Bissell Point) ● For evaluation of sale of steam from energy recovery of FBI exhaust gas at the Bissell Point WWTF: identification of suitable alternative, development of criteria, and evaluation of the alternative Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-1 2.0 Lemay WWTF 2.1 BACKGROUND 2.1.1 FBI Sizing and Loading Criteria Design solids quantities for current and future conditions were developed as part of TM 04 Solids Quantities and Characteristics. For the Lemay WWTF solids production is projected at 165 dry tons per day (dtpd) for future maximum month (MM), 112 dtpd for future annual average (AA), 110 dtpd for current MM, and 74 dtpd for current AA. The size and quantities of FBI units were selected as part of TM 09 FBI Design Criteria. For the Lemay WWTF the alternative selected consisted of 2 units sized to meet future MM, with one additional standby unit (i.e. three total units) to process solids above MM production and provide capacity when units are out of service for maintenance. Design criteria for the FBI units are listed in Table 2-1. Table 2-1 Lemay FBI Design Criteria DESCRIPTION VALUE Number of units 3 Nominal design capacity, each 83 dtpd Firm nominal capacity 165 dtpd Installed nominal capacity 249 dtpd Bed outside diameter 17.6 feet Design fluidizing air 9,948 scfm Max flood capacity (30.8% TS, 50.8% VS), each 91 dtpd Max normal capacity (28.9% TS, 60.1% VS), each 83 dtpd Nominal normal design capacity (28.9% TS, 60.1% VS), each 75 dtpd dtpd = dry tons per day, scfm = standard cubic feet per minute, TS = total solids, VS = volatile solids 2.1.2 Ameren Energy Incentives If steam turbine-generators were installed as part of the new FBI facilities, they would qualify for the Ameren Missouri Business Energy Efficiency Program “BizSavers.” This equipment would fall under their Custom Incentives portion of the program for commercial and industrial customers. These custom incentive payments are calculated based on annual energy savings of the proposed equipment. The steam turbine-generators would most likely fall under the “miscellaneous” category which has an incentive rate of $0.07 per kW-hr saved. Based on the maximum energy production calculated for electricity generation alternatives, the Lemay WWTF could be eligible for up to $400,000 and the Bissell Point WWTF for up to $500,000 in incentives. The “BizSavers” team from Ameren would need to be involved in the design stage, and all applications would need to be submitted before any equipment is purchased or installed. During this process, they would verify the energy production estimates and also determine the energy demand reduction potential on their end. Based on this, they would determine the value of their incentive offer, and all incentives Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-2 greater than $15,000 would also require an additional pre-installation inspection to complete the process. Although these incentives would help to reduce energy recovery costs and thus make it more financially attractive, at the scale that the District would be considering, these incentives would in fact have minimal impact to the overall economic evaluation (as described in the following sections of this technical memorandum). 2.1.3 Past Evaluations Energy recovery assessments have been completed in the past. As part of the Solids Handling Master Plan (SMP) finalized in 2010, power generating energy recovery alternatives were developed for both the existing multiple hearth incinerators option and for new FBIs option. The alternative for new FBIs is of most interest for the current project and was based on recovering heat from the FBI exhaust gas to produce high pressure superheated steam for power generation. The energy recovery system as evaluated in Phase II TM 2 – Lemay WWTP Solids Processing Alternatives Evaluation consisted of: Waste heat boilers (WHBs) Ash pneumatic conveyance Condensing steam turbine-generator Steam system including condenser, condensate pumps, cooling heat exchanger, condensate storage tank, deaerator, and WHB feed pumps Packaged water treatment system for boiler water make up. Design criteria for major energy recovery system components is shown in Table 2-2. Table 2-2 SMP (2010) TM2 Lemay Energy Recovery Alternative Design Criteria DESCRIPTION CRITERIA Waste Heat Boilers Number 2 Type Water tube Design flue gas flow 65,000 pph Steam pressure 400 psia Steam temperature 600oF (superheated) Steam flow1, (less parasitic loads, i.e. deaerator) 11,250 pph WHB Fly Ash Transport System Type Pneumatic Steam Turbine Generator Number 1 Type Condensing to 4” Hg Steam pressure 400 psia Steam temperature 600oF (superheated) Design steam flow 12,900 pph Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-3 DESCRIPTION CRITERIA Alternator type Synchronous Power output 0.8 MW Steam Surface Condenser Number 1 Type Water cooled Cooling Water Heat Exchangers Number 2 (1 duty, 1 standby) Condensate Handling System Condensate storage tank number 1 Condensate storage tank capacity 750 gallons Deaerator number 1 Deaerator condensate flow rate 12,900 pph Deaerator steam use 1,000 pph WHB feed pump number 2 (1 duty, 1 standby) Packaged Water Treatment System Number 2 (1 duty, 1 standby) Treated water flow 10 gpm pph = pounds per hour, 1Steam produced at annual average conditions Life cycle costs were developed as part of the evaluation and a summary is shown in Table 2-3. Table 2-3 SMP (2010) TM2 Lemay Opinions of Costs, Savings, and Life Cycle Costs ALTERNATIVE L-3 FBI + CFG1 L-3-A FBI + POWER2 Capital Costs3 $121,211,000 $24,233,000 Salvage Value ($2,622,000) ($494,000) Annual O&M Costs $4,913,000 $565,000 Annual Revenue ($0) ($182,000) Present Worth Costs Capital $121,211,000 $24,233,000 Salvage ($988,000) ($186,000) O&M $61,229,000 $7,041,000 Revenue ($0) ($2,268,000) Total Present Worth Costs $181,452,000 $28,810,000 1Alternative L-3 FBI + CFG - new FBI units with centrifuge dewatering technology Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-4 2Alternative L-3-A FBI + POWER – differential additional costs of electricity production from steam to base costs (Alt L-3 FBI + CFG) for new FBI units with centrifuge dewatering technology 3Costs provided are in 2010 dollars As shown by the present worth analysis, annual costs to operate the waste energy recovery facility were greater than the revenue generated, and the capital investment did not have a payback period. As part of the same project, a triple bottom line evaluation, considering economic, social, and environmental criteria was performed in Phase II TM 10 Triple Bottom Line Evaluation. The overall weighted total score for the alternative of new FBI units with centrifuge dewatering without energy recovery (L-3 FBI + CFG) was 34.60, while the score for the alternative with energy recovery (L-3-A FBI + STG) was 30.80, indicating that the alternative without energy recovery scored higher when both economic and non-economic factors were considered. 2.2 BUILDING HEATING 2.2.1 Existing Steam System The existing steam system (commissioned in 1968) consists of four waste heat boilers, located in the Incinerator and Filter Building (that recover energy from the exhaust gas of multiple hearth incinerators), and two natural gas fired auxiliary boilers (located in the Maintenance Building). The steam supply system provides steam to multiple uses in several buildings as follows: Incinerator and Filter Building: Air handling unit (AHU) heating coils, boiler feedwater heat exchangers, and fly ash nozzles Maintenance Building: Water heater, AHU humidifier, chillers, and heating water heat exchangers West and East Trash Buildings: AHU coils Biofilter Blower and Thickener Building: Water heater, AHU humidifiers, chillers, and heating water heat exchangers Primary Control Building: Duct mounted humidifier and duct mounted reheat coil Condensate from the multiple buildings, except the Biofilter and Primary Control Building, is returned to a condensate surge tank located in the Maintenance Building. Condensate pumps convey the condensate to the deaerator from which boiler feed pumps convey it to the boilers. A schematic of the existing steam heating system is shown in Figure 2-1. In 2007 the steam system was modified, which included removal and addition of heating coils and other HVAC equipment. Based on steam production records there was a significant reduction in steam use after the modification project. Plant staff have indicated that the waste heat boilers are in poor condition, with only two of the four units currently in operation. Otherwise it is thought that much of the rest of the steam system is in suitable condition, including the piping and heating coils. With proper maintenance, steam and condensate piping can have a long service life, in excess of 50 years. Steam boilers, tanks and deaerators, have a more limited typical service life of 15 to 20 years, but can last 2 to 3 times longer than that with good maintenance and periodic replacement of deteriorated components. Steam alternatives were evaluated based on replacing the major equipment components, the boilers, condensate surge tank, deaerator, and associated pumps, but Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-5 utilizing the existing steam and condensate piping. If a steam heating alternative is selected it is recommended that the steam and condensate systems be inspected to determine the specific condition of the system components, including ultrasonically testing the piping and comparing the current performance of major equipment with original specifications. Steam production data from the years 2016, 2017, and 2018 were analyzed to determine average and design steam use. Design criteria of the existing steam system is listed in Table 2-4. Table 2-4 Existing Steam System Design Criteria DESCRIPTION CRITERIA Historic Steam Production Average annual production 117,305,000 pounds Average daily / hourly production 322,000 ppd / 13,416 pph Average waste heat steam % of total 60% Design daily / hourly production (97.5% of days) 537,250 ppd / 22,385 pph Design Steam Production (85% usage factor) 26,500 pph Waste Heat Boilers Number 4 (one per MHI, only 2 operating) Make / model International Boiler Works / IVH-9_15 Exhaust gas inlet temperature 1400oF Exhaust gas outlet temperature 500oF Exhaust gas flow 52,363 pph Design steam pressure 200 psig Operating steam pressure 125 psig Steam temperature 353oF Steam flow 15,000 pph Auxiliary Boilers Number 2 Make / model Superior Boiler Works / 300-HP APACHE Type Scotch Marine Steam pressure 150 psig Steam flow 10,350 pph Gas input 12.6 MMBtuh pph = pounds per hour, ppd = pounds per day, MMBtuh = million BTUs per hour Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-6 Figure 2-1 Existing Steam Heating System Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-7 2.2.2 Building Heating Alternatives Three building heating alternatives were evaluated: Alternative 1 – Steam Heating – FBI Waste Heat Boilers (A1 ST-WHB) ● Provide new WHBs with the new FBI system, natural gas fired auxiliary (steam) boilers, new steam and condensate piping between the new FBI Building and the existing Maintenance Building and reuse the balance of the existing steam system Alternative 2 – Steam Heating – Natural Gas Boilers (A2 ST-NGB) ● Provide new natural gas fired boilers in the Maintenance Building and reuse the balance of the existing steam system. No new WHBs will be provided for the new FBI system. Alternative 3 Direct Fired Natural Gas Heating (A3 NG-SYS) ● Abandon the existing steam system and provide new natural gas fired heating equipment at each facility supplied by the existing steam system. 2.2.2.1 Alternative 1 ST-WHB, Steam Heating – FBI Waste Heat Boilers Under this alternative, new WHBs would be provided with the new FBI system, new auxiliary boilers would replace the existing boilers, and much of the existing steam heating system would continue to be used. Two WHBs and ductwork would be provided so that any of the three FBI systems when operating could feed a WHB or bypass the boilers. Major components of this alternative would include: WHBs to capture heat from the FBI exhaust gas and produce saturated steam Refractory lined ductwork and dampers for FBI exhaust gas conveyance and bypass duct Steam and condensate piping between the new FBI Building and existing Maintenance Building New natural gas fired auxiliary boilers located in the Maintenance Building to supply steam when the WHB supply is insufficient or the equipment is out of service, new condensate surge tank and deaerator. Each auxiliary boiler is sized to provide full heating load. Reuse of the balance of existing steam and condensate piping, steam heating equipment, and other miscellaneous items using steam The existing Maintenance Building would have to be evaluated to confirm the location of the existing auxiliary boilers has sufficient space and combustion air supply for the new auxiliary boilers. Design criteria for system components under this alternative are shown in Table 2-5. Table 2-5 A1 ST-WHB, Steam Heating – FBI WHB Design Criteria DESCRIPTION CRITERIA Waste Heat Boilers Number 2 Type Water tube Exhaust gas inlet temperature 950oF Exhaust gas outlet temperature 450oF Exhaust gas flow, each 68,000 pph Design steam pressure 200 psig Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-8 DESCRIPTION CRITERIA Operating steam pressure 125 psig Steam temperature 353oF (Saturated) Steam flow, each 9,500 pph Auxiliary Boilers Number 2 (1 duty, 1 standby) Type Scotch Marine Steam pressure 125 psig Steam flow, each 26,500 pph Gas input, each 33.5 MMBtuh pph = pounds per hour, MMBtuh = million Btus per hour 2.2.2.2 Alternative 2 ST-NGB, Steam Heating – NG Boilers Under this alternative, new natural gas fired boilers would replace the existing auxiliary boilers, and much of the existing steam heating system would continue to be used. Major components of this alternative would include: New natural gas fired boilers located in the Maintenance Building to supply steam, new condensate surge tank, deaerator, and associated pumps Reuse of the balance of existing steam and condensate piping, steam heating equipment, and other miscellaneous items using steam The existing Maintenance building would have to be evaluated to confirm the location of the existing auxiliary boilers has sufficient space and combustion air supply. Design criteria for system components under this alternative are shown in Table 2-6. Table 2-6 A2 ST-NGB, Steam Heating – NG Boilers Design Criteria DESCRIPTION CRITERIA Natural Gas Fired Boilers Number 2 (1 duty, 1 standby) Type Scotch Marine Steam pressure 125 psig Steam temperature 353oF (saturated) Steam flow 26,500 pph Gas input 33.5 MMBtuh pph = pounds per hour, MMBtuh = million Btus per hour 2.2.2.3 Alternative 3 NG-SYS, Direct Fired NG Heating Under this alternative, new natural gas fired heating equipment would be provided at each facility supplied by the existing steam system; with the existing system either abandoned or demolished. Major components of this alternative would include: Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-9 New natural gas fired AHUs to replace each existing AHU that has a steam coil in the Incinerator and Filter Building and the Blower and Thickener Building New gas distribution piping to new gas fired equipment Replacement of miscellaneous equipment currently using steam, including the heating water heat exchangers (replaced with natural gas fired hot water boilers), steam chillers (replaced with electrical chillers), AHU humidifier, and water heater, with new electric or natural gas fired equipment serving the same purpose. Equipment, such as hot water coil AHUs in the Maintenance and Blower and Thickener Buildings, that use hot water from the steam/hot water heat exchangers, would be reused with hot water supplied by the new hot water boilers. Design criteria for major system components under this alternative are shown in Table 2-7. Table 2-7 A3 NG-SYS, Direct Fired NG Heating Design Criteria DESCRIPTION CRITERIA General Total design energy used by HVAC equipment being replaced 61.7 MMBtuh AHUs in Incinerator & Filter Building and Trash Buildings Number and location Same as existing Type Direct fired ng Capacity Same as existing Heating Water Boilers (HWBs) Maintenance Bldg HWBs number 2 (1 duty, 1 standby) Maintenance Bldg HWBs output, each 26.8 MMBtuh Maintenance Bldg HWBs heating water supply temperature 200oF Blower & Thickener Bldg number 2 (1 duty, 1 standby) Blower & Thickener Bldg output, each 14.5 MMBtuh Blower & Thickener Bldg heating water supply temperature 200oF Maintenance Building Chillers Number 2 (1 duty, 1 standby) Capacity, each 300 tons pph = pounds per hour, MMBtuh = million BTUs per hour 2.2.3 Costs 2.2.3.1 Opinion of Probable Project Costs A planning level opinion of probable project cost (OPPC) is shown in Table 2-8 for the alternatives. The OPPC includes: Construction contingency (35%) Contractor costs 23.7% ● General requirements (10%) Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-10 ● Contractor fee (12%) ● Insurance and bond (1.7%) Table 2-8 Lemay Building Heating Alternatives OPPC ALTERNATIVE A1 ST-WHB A2 ST-NGB A3 NG-SYS WHB Building $1,755,000 NA NA WHBs $3,000,000 NA NA WHB ductwork $1,594,000 NA NA Yard steam piping $200,000 $100,000 NA WHB fly ash transport system $643,000 NA NA Aux/NG boilers $750,000 $750,000 NA Condensate tank/deaerator $641,000 $641,000 NA Equipment installation $755,000 $209,000 $578,000 NG AHUs NA NA $1,456,000 Yard/building NG piping NA NA $40,000 Miscellaneous equipment NA NA $1,434,000 Electrical $463,000 $128,000 $231,000 I&C $405,000 $112,000 $202,000 Contractor costs $2,419,000 $460,000 $934,000 Construction contingency $4,419,000 $840,000 $1,706,000 Engineering and legal $3,409,000 $648,000 $1,316,000 Project cost $20,453,000 $3,888,000 $7,897,000 Alt 1 (ST-WHB) – Steam heating with new WHBs and Aux boilers; Alt 2 (ST-NGB) – Steam heating with new NG boilers; Alt 3 (NG-SYS) – New NG fired heating equipment, NA = Not applicable 2.2.3.2 Operating Costs For the purpose of comparing costs, annual operating costs that would have a significant difference between alternatives were modeled consisting of fuel and maintenance costs. Table 2-9 shows these costs for the alternatives. Operating costs are based on: 24 hour per day, 7 days per week operation Natural gas cost of $4.50 per 1,000 cubic foot Annual process equipment maintenance cost based on 2% of equipment cost Annual HVAC equipment maintenance cost based on 0.5% of equipment cost Maintenance cost calculations were based on a capital cost of $4 million for new HVAC systems for the purpose of applying maintenance allowances. For the steam alternatives, the process equipment maintenance allowance was used for one half ($2 million) of the HVAC costs, based on Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-11 steam components, such as the piping and traps, being reflective of process equipment for maintenance level of effort, rather than HVAC equipment. Table 2-9 Lemay Building Heating Alternatives Annual Differential Operating Costs ALT A1 ST-WHB A2 ST-NGB A3 NG-SYS NG Fuel $198,000 $660,000 $594,000 Maintenance and labor $377,000 $155,000 $20,000 Total $575,000 $815,000 $614,000 Alt 1 (ST-WHB) – Steam heating with new WHBs and Aux boilers; Alt 2 (ST-NGB) – Steam heating with new NG boilers; Alt 3 (NG-SYS) – New NG fired heating equipment 2.2.3.3 Present Worth Costs Present worth costs for each alternative are shown in Table 2-10. Total present worth costs are based on: Evaluation period: 20 year Interest rate: 4% Escalation rate: 2.5% Table 2-10 Lemay Building Heating Alternatives Present Worth Costs ALT A1 ST-WHB A2 ST-NGB A3 NG-SYS O&M PW $9,908,000 $14,037,000 $10,577,000 OPCC $20,453,000 $3,888,000 $7,897,000 Total $30,361,000 $17,925,000 $18,474,000 Alt 1 (ST-WHB) – Steam heating with new WHBs and Aux boilers; Alt 2 (ST-NGB) – Steam heating with new NG boilers; Alt 3 (NG-SYS) – New NG fired heating equipment 2.2.4 Non-Economic Criteria Table 2-11 has a summary of advantages and disadvantages for each building heating alternative. Table 2-11 Lemay Building Heating Alternatives Present Worth Costs A1 ST-WHB A2 ST-NGB A3 NG-SYS Advantages · Recovers waste energy to reduce fossil fuel use and cost · Lowest capital costs · Effectively utilizes existing assets · Simple system to operate · Lowest O&M costs Disadvantages · Substantially more capital cost not justified by annual savings · Adds operational complexity to FBI system · More maintenance effort than NG system · Greater capital costs than new ng steam boiler alternative Alt 1 (ST-WHB) – Steam heating with new WHBs and Aux boilers; Alt 2 (ST-NGB) – Steam heating with new NG boilers; Alt 3 (NG-SYS) – New NG fired heating equipment Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-12 2.2.5 Evaluation and Recommendation The WHB alternative has substantial capital cost that isn’t justified by the limited annual cost savings. Additionally, operating the WHBs will add complexity to the FBI trains, which will already have many advanced air pollution equipment process components to operate in conjunction with the combustion reactor. For these reasons, the WHB steam building heating alternative is not recommended. The building heating alternatives were based on the same building use and HVAC requirements as the existing buildings as determining future use and HVAC requirements is outside the scope of this technical memorandum. Future use for these buildings may significantly change their HVAC requirements. The natural gas fired equipment alternative has lower operating and maintenance effort with higher capital costs, while the natural gas fired boiler steam building heating alternative has lower capital costs, but greater operating and maintenance costs and effort. The present worth cost difference of these alternatives is within the margin of error for the estimates. Given that the future use for these buildings may impact the relative merits of these alternatives, it is recommended that the type of future heating system be reevaluated when the future use of the buildings is determined. As such, Alternative A-2 would be the preferred alternative based on capital costs alone until such time as the future use of the building is defined. If the future use of the building results in no change to the current HVAC requirements; then Alternative A-2 and A-3 are essentially economically equivalent and A-3 would be preferable from a non-economic standpoint. 2.3 ELECTRICITY GENERATION 2.3.1 Electricity Generation Facility In order to determine if it would be beneficial to include energy recovery with electricity generation for the new FBI facility at the Lemay WWTF an alternative was developed based on recovering energy from the FBI exhaust gas and producing steam from the energy to power a steam turbine generator. The energy recovery system for electricity power generation would be similar to the system previously evaluated as part of the Solids Master Plan. Two WHBs and ductwork would be provided so that any of the FBI systems when operating could feed a WHB or bypass the boilers. The energy recovery system would consist of: Waste heat boilers (WHB), with super heaters, evaporators, and economizers, to capture heat from the FBI exhaust gas and produce superheated steam Refractory lined ductwork and dampers for FBI exhaust gas conveyance and bypass duct Pneumatic conveyance system to transport ash from the WHB hoppers to the ash system, including transporter and air compressors Condensing steam turbine-generator to convert steam to electrical power Steam condenser to condense steam on the discharge of the turbine and condensate pumps to convey condensate to condensate storage tank Cooling heat exchanger to transfer heat from the closed water circuit providing cooling to the condenser to plant effluent Condensate system consisting of condensate storage tank, deaerator, and WHB feed pumps Packaged water treatment system to treat potable water for boiler water make up, including filters, carbon filters, water softeners, reverse osmosis, demineralizers, demineralized water storage tank and make up water pumps Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-13 Building area to house the energy recovery system. Design criteria for major energy recovery system components is shown in Table 2-12. Table 2-12 Lemay Electricity Generation Design Criteria DESCRIPTION CRITERIA Waste Heat Boiler Number 2 Type Water tube, vertical Flue gas inlet 950oF Flue gas outlet 446oF Design flue gas flow 73,000 pph Steam pressure 450 psig Steam temperature 600oF (superheated) Steam flow, nominal capacity, each 8,850 pph Steam flow, max rating, each 12,000 pph Steam flow, each (less parasitic loads, i.e. deaerator) 10,800 pph WHB Fly Ash Transport System Type Pneumatic Number of transporters 2 Number of compressors 2 Steam Turbine Generator Number 1 Turbine type Horizontal, multi-stage, condensing, impulse Steam pressure 400 psig Steam temperature 600oF (superheated) Maximum design steam flow 23,000 pph Nominal steam flow with 1 WHB 10,800 pph Nominal steam flow with 2 WHB 21,600 pph Alternator type Synchronous Alternator speed 1,800 Power output with 1 WHB 716 kW Power output with 2 WHB 1,697 kW Output voltage 4,160 V Steam Surface Condenser Number 1 Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-14 DESCRIPTION CRITERIA Type Water cooled Condensate pump number 2 (1 duty, 1 standby) Condensate pump capacity 48 gpm, each Cooling Water Heat Exchangers Number 2 (1 duty, 1 standby) Cooling fluid (effluent) flow 2,550 gpm Cooled fluid (recirculated potable water) flow 2,180 gpm Condensate Handling System Condensate storage tank number 1 Condensate storage tank capacity 1,850 gallons Deaerator number 1 Deaerator capacity, min 10 minutes Deaerator condensate flow rate 24,000 pph Deaerator steam use 1,000 - 2000 pph WHB feed water pump number 3 (2 duty, 1 standby) WHB feed water pump flow 27 gpm, each WHB feed water pump approximate head 1,200 ft Packaged Water Treatment System Number 2 (1 duty, 1 standby) Treated water flow 11 gpm Make up water tank capacity 1,900 gallons 2.3.2 Costs 2.3.2.1 Opinion of Probable Project Costs A planning level opinion of probable project cost (OPPC) are shown in Table 2-13 for the Lemay WWTF Electricity Generation Alternative. The allowances used are the same as for the Lemay WWTF Building Heating evaluation. Table 2-13 Lemay Electricity Production Alternative OPPC DESCRIPTION COST WHB Building $2,205,000 WHBs $4,390,000 WHB fly ash transport system $643,000 Steam turbine generator $1,472,000 Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-15 DESCRIPTION COST Steam condenser $378,000 Cooling water heat exchangers $311,000 Condensate handling system $641,000 Packaged water treatment system $151,000 Equipment installation $1,175,000 Process Piping $2,024,000 Process Ductwork $1,594,000 Electrical (8%) $733,000 I&C (7%) $641,000 Contractor costs (23.7%) $3,877,000 Construction Contingency (35%) $7,082,000 Engineering and Legal (20%) $5,463,000 Project Costs $32,780,000 2.3.2.2 Operating Costs Annual operating costs were developed for electrical, labor and maintenance costs for both future AA (FAA) and current AA (CAA) conditions. Table 2-14 shows these costs for the alternatives. Operating costs are based on: 24 hour per day, 7 days per week operation Electricity cost of $0.068 per kW-hr Labor costs of $24/hour Annual maintenance cost based on 2% of equipment cost and 0.5% of building capital cost Table 2-14 Lemay Electricity Generation Annual Differential Operating Costs ITEM CAA FAA Electrical Savings ($268,000) ($403,000) Maintenance $165,000 $165,000 Labor $235,000 $235,000 Total $132,000 ($2,000) 2.3.2.3 Present Worth Costs Present worth costs for the Lemay Electricity Generation alternative are shown in Table 2-15. Total present worth costs are based on: Evaluation period: 20 years Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Lemay WWTF 2-16 Interest rate: 4% Escalation rate: 2.5% Current conditions modeled for years 0 to 10, future conditions modeled for years 11 to 20 Table 2-15 Lemay Electricity Generation Alternative Present Worth Costs ITEM COST O&M PW $1,186,000 OPCC $32,780,000 Ameren Incentive ($400,000) Total $33,566,000 2.3.3 Non-Economic Criteria Table 2-16 has a summary of advantages and disadvantages for the Lemay Electrical Generation alternative. Table 2-16 Lemay Electricity Generation Advantages and Disadvantage ITEM SUMMARY Advantages · Recovers waste energy to create renewable energy and reduce electricity costs Disadvantages · Substantially more capital cost not justified by annual savings · Adds operational complexity to FBI system 2.3.4 Evaluation and Recommendation The Lemay Electricity Generation alternative has substantial capital cost that isn’t justified by the annual cost savings and operating the WHBs will add complexity to the FBI trains, which will already have many advanced air pollution equipment process components to operate in conjunction with the combustion reactor. These results are similar to the previous electricity generation evaluation done for the Solids Master Plan work. For these reasons, the Lemay Electricity Generation alternative is not recommended. To accommodate the option for adding energy recovery in the future, it is recommended that the system is configured such that take-off duct is included for re-routing of waste heat to a future adjacent building; which would house a waste heat boiler, steam turbine, and steam system (condenser, de-aerators, pumps, water treatment system, etc.). With such a configuration, additional costs are not necessary at this time while still configuring the system to allow for the implementation of future energy recovery systems. Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-1 3.0 Bissell Point WWTF 3.1 BACKGROUND 3.1.1 FBI Sizing and Loading Criteria Design solids quantities for current and future conditions were developed as part of TM 04 Solids Quantities and Characteristics. For the Bissell Point WWTF solids production is projected at 250 dtpd for future MM, 135 dtpd for future AA, 114 dtpd for current AA. The size and quantities of FBI units were selected as part of TM 09 FBI Design Criteria. For the Bissell Point WWTF the alternative was selected that consisted of 3 units sized to meet future MM, with one additional standby unit to process solids above MM production and provide capacity when units are out of service for maintenance. Design criteria for the FBI units are listed in Table 3-1. Table 3-1 Bissell Point FBI Design Criteria DESCRIPTION VALUE Number of units 4 Nominal design capacity, each 83 dtpd Firm nominal capacity 250 dtpd Installed nominal capacity 334 dtpd Bed outside diameter 15.7 feet Design fluidizing air 9,743 scfm Max flood capacity (33.4 %TS, 32.2 %VS), each 92 dtpd Nominal normal capacity (29.7 %TS, 50.8 %VS), each 68 dtpd dtpd = dry tons per day, scfm = standard cubic feet per minute, TS = total solids, VS = volatile solids 3.1.2 Past Evaluations Energy recovery assessments have been completed in the past. As part of the Solids Handling Master Plan (SMP), steam energy recovery alternatives were developed for both the existing multiple hearth incinerators option and new FBIs option. The alternatives for new FBIs are of most interest for the current project and were based on recovering heat from the FBI exhaust gas to produce either medium pressure steam for sale to Trigen or high pressure superheated steam for on-site power generation, as identified in the Phase II TM 1 – Bissell Point WWTP Solids Processing Alternatives Evaluation. The medium pressure steam for sale to Trigen alternative, identified as Alternative B-2-A in TM1, consisted of: Waste heat boilers (WHBs) Ash pneumatic conveyance Packaged water treatment system for boiler water. The packaged water treatment system was designed for a once-through use steam system with no condensate return from Trigen. Design criteria for major energy recovery system components of the medium pressure steam for sale alternative is shown in Table 3-2. Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-2 Table 3-2 SMP (2010) TM1 Bissell Point Sale of Medium Pressure Steam Alternative Design Criteria DESCRIPTION CRITERIA Waste Heat Boilers Number 2 (one per FBI) Type Water tube Design flue gas flow 68,250 pph Steam pressure 180 psia Steam temperature 373oF (saturated) Steam flow (less parasitic loads, i.e. deaerator) 15,100 pph WHB Fly Ash Transport System Type Pneumatic Packaged Water Treatment System Number 2 (1 duty, 1 standby) Treated water flow 50 gpm pph = pounds per hour The high pressure superheated steam for on-site power generation alternative, identified as Alternative B-2-B consisted of: Waste heat boilers (WHBs) Ash pneumatic conveyance Condensing steam turbine-generator Steam system including condenser, condensate pumps, cooling heat exchanger, condensate storage tank, deaerator, and WHB feed pumps Packaged water treatment system for boiler water make up. Design criteria for major energy recovery system components of the high pressure steam for on- site power generation is shown in Table 3-3. Table 3-3 SMP (2010) TM1 Bissell Point Power Generation Alternative Design Criteria DESCRIPTION CRITERIA Waste Heat Boilers Number 2 (one per FBI) Type Water tube Design flue gas flow 68,250 pph Steam pressure 400 psia Steam temperature 600oF (superheated) Steam flow 11,800 pph1 Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-3 DESCRIPTION CRITERIA WHB Fly Ash Transport System Type Pneumatic Steam Turbine Generator Number 1 Type Condensing to 4” Hg Steam pressure 400 psia Steam temperature 600oF (superheated) Design steam flow 16,400 pph2 Alternator type Synchronous Power output 1.0 MW Steam Surface Condenser Number 1 Type Water cooled Cooling Water Heat Exchangers Number 2 (1 duty, 1 standby) Condensate Handling System Condensate storage tank number 1 Condensate storage tank capacity 900 gallons Deaerator number 1 Deaerator condensate flow rate 16,400 pph Deaerator steam use 1,000 to 2,000 pph WHB feed pump number 2 (1 duty, 1 standby) Packaged Water Treatment System Number 2 (1 duty, 1 standby) Treated water flow 15 gpm pph = pounds per hour 1Less parasitic loads, i.e. deaerator, etc. 2Steam turbine sized for steam rate prior to parasitic load deduction Life cycle costs were developed as part of the evaluation and a summary is shown in Table 3-4. Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-4 Table 3-4 SMP (2010) TM1 Bissell Point Opinions of Costs, Savings, and Life Cycle Costs ALTERNATIVE B-2 FBI + CFG1 B-2-A FBI + STEAM2 B-2-B FBI + POWER3 Capital Costs $175,732,000 $15,559,000 $29,003,000 Salvage Value ($4,556,000) ($1,861,000) ($494,000) Annual O&M Costs $7,860,000 $383,000 $691,000 Annual Revenue ($0) ($855,000) ($806,000) Present Worth Costs Capital $175,732,000 $15,559,000 $29,003,000 Salvage ($1,717,000) ($701,000) ($186,000) O&M $97,947,000 $4,773,000 $8,611,000 Revenue ($0) ($10,655,000) ($10,971,000) Total Present Worth Costs $271,962,000 $8,976,000 $26,457,000 1Alternative B-2 FBI + CFG - new FBI units with centrifuge dewatering technology 2Alternative B-2-A FBI + STEAM – differential additional costs of steam production for sale to base costs of new FBI units with centrifuge dewatering technology 3B-2-B FBI + POWER - differential additional costs of electricity production from steam to base costs of new FBI units with centrifuge dewatering technology As shown by the analysis both energy recovery alternatives had a positive overall present worth cost meaning that overall costs were greater than benefits for the review period and there was not a positive payback on investment. As part of the same project, a triple bottom line evaluation, considering economic, social, and environmental criteria was performed in Phase II TM 10 Triple Bottom Line Evaluation. The overall weighted total score for the alternative of new FBI units with centrifuge dewatering without energy recovery (B-2 FBI + CFG) was 39.70, the score for the alternative with steam for sale energy recovery (B-2-A FBI + ST) was 36.25, and the score for the alternative with steam for power generation energy recovery was 36.55, indicating that the alternative without energy recovery scored higher when both economic and non-economic factors were evaluated. 3.2 ELECTRICITY PRODUCTION 3.2.1 Electricity Generation Facility In order to determine if it would be beneficial to include energy recovery with electricity generation for the new FBI facility at the Bissell WWTF an alternative was developed based on recovering energy from the FBI exhaust gas and producing steam from the energy to power a steam turbine generator. The energy recovery system for electricity power generation would be similar to the system previously evaluated as part of the Solids Master Plan. Two WHBs and ductwork would be provided so that any of the four FBI systems when operating could feed a WHB or bypass the boilers. The energy recovery system would consist of the same components as the Lemay WWTF Electricity Generation Alternative. Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-5 Because the FBI reactors for both Lemay and Bissell Point WWTFs have a nominal 83 dtpd capacity, the sizing criteria for two waste heat boilers and associated steam system would be the same for the Bissell Point WWTF Electricity Generation alternative as for the Lemay WWTF Electricity Generation alternative. Design criteria for major energy recovery system components is shown in Table 2-12: Lemay Electricity Generation Design Criteria. 3.2.2 Costs 3.2.2.1 Opinion of Probable Project Costs Because the FBI reactors and energy recovery system for both Lemay and Bissell Point WWTFs had the same sizing the OPPC was the same for the Bissell Point WWTF Electricity Generation alternative as for the Lemay WWTF Electricity Generation alternative. A planning level OPPC for the energy recovery system at both WWTFs are shown in Table 2-13: Lemay Electricity Production Alternative OPPC. The total project costs for the energy recovery system was $32,780,000. 3.2.2.2 Operating Costs Annual operating costs were developed for electrical, labor and maintenance costs for both future AA (FAA) and current AA (CAA) conditions. Although the energy recovery system for the Bissell Point WWTF was sized similarly to the Lemay WWTF, the solids production rates are different, and the operating costs will be different based on the plant specific production rates. Table 3-5 shows these costs for the alternatives. Operating costs are based on: 24 hour per day, 7 days per week operation Electricity cost of $0.068 per kW-hr Labor costs of $24/hour Annual maintenance cost based on 2% of equipment cost and 0.5% of building capital cost Table 3-5 Bissell Point Electricity Generation Annual Differential Operating Costs ITEM CAA FAA Electrical Savings ($454,000) ($533,000) Maintenance $165,000 $165,000 Labor $235,000 $235,000 Total ($54,000) ($132,000) 3.2.2.3 Present Worth Costs Present worth costs for the Bissell Point Electricity Generation alternative are shown in Table 3-5. Total present worth costs are based on: Evaluation period: 20 years Interest rate: 4% Escalation rate: 2.5% Current conditions modeled for years 0 to 10, future conditions modeled for years 11 to 20 Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-6 Table 3-6 Bissell Point Electricity Generation Alternative Present Worth Costs ITEM COST O&M PW ($1,576,000) OPCC $32,780,000 Ameren incentive ($500,000) Total $30,704,000 3.2.3 Non-Economic Criteria Table 3-7 has a summary of advantages and disadvantages for the Bissell Point Electrical Generation alternative. Table 3-7 Bissell Electricity Generation Advantages and Disadvantage ITEM SUMMARY Advantages · Recovers waste energy to create renewable energy and reduce electricity costs Disadvantages · Substantially more capital cost not justified by annual savings · Adds operational complexity to FBI system 3.2.4 Evaluation and Recommendation Similar to the Lemay Electricity Generation alternative, the Bissell Point Electricity Generation alternative has substantial capital cost that isn’t justified by the annual cost savings and operating the WHBs will add complexity to the FBI trains, which will already have many advanced air pollution equipment process components to operate in conjunction with the combustion reactor. These results are similar to the previous electricity generation evaluation done for the Solids Master Plan work. For these reasons, the Bissell Point Electricity Generation alternative is not recommended. 3.3 SALE OF STEAM TO PROCTOR & GAMBLE 3.3.1 Steam Generation Facility An alternative was developed to evaluate the sale of steam generated at the Bissell Point WWTF to the Proctor & Gamble (P&G) plant located nearby based on recovering energy from the FBI exhaust gas and producing steam to convey for off-site use. The energy recovery system would consist of: WHBs to capture heat from the FBI exhaust gas and produce saturated steam Refractory lined ductwork and dampers for FBI exhaust gas conveyance and bypass duct Pneumatic conveyance system to transport ash from the WHB hoppers to the ash system, including transporter and air compressors Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-7 Steam piping between the new FBI Building and P&G plant, based on above grade piping with yard supports and foundations Deaerator and WHB feed pumps Packaged water treatment system to treat potable water for boiler water Building area to house the energy recovery system Design criteria for major energy recovery system components is shown in Table 3-8. Table 3-8 Bissell Point Sale of Steam Design Criteria DESCRIPTION CRITERIA Waste Heat Boiler Number 2 Type Water tube Flue gas inlet 950oF Flue gas outlet 450oF Design flue gas flow 73,000 pph Design steam pressure 200 psig Operating steam pressure 125 psig Steam temperature 353oF (saturated) Steam flow, each 9,500 pph WHB Fly Ash Transport System Type Pneumatic Number of transporters 2 Number of compressors 2 Deaerator and WHB Pumps Deaerator number 1 Deaerator capacity, min 10 minutes Deaerator condensate flow rate 0 pph Deaerator steam use 1,000 - 2000 pph WHB feed water pump number 3 (2 duty, 1 standby) WHB feed water pump flow 27 gpm, each WHB feed water pump approximate head 1,200 ft Packaged Water Treatment System Number 2 (1 duty, 1 standby) Treated water flow 50 gpm Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-8 3.3.2 Costs 3.3.2.1 Opinion of Probable Project Costs A planning level OPPC is shown in Table 3-9 for the Bissell Point WWTF Sale of Steam Alternative. The allowances used are the same as for the Lemay WWTF Building Heating evaluation. Table 3-9 Bissell Sale of Steam Alternative OPPC DESCRIPTION COST WHB Building $1,755,000 WHBs $3,000,000 WHB fly ash transport system $643,000 Steam conveyance piping $546,000 Deaerator and WHB pumps $641,000 Packaged water treatment system $300,000 Equipment installation $688,000 Process Piping $200,000 Process Ductwork $1,594,000 Electrical (8%) $422,000 I&C (7%) $369,000 Contractor costs (23.7%) $2,407,000 Construction Contingency (35%) $4,398,000 Engineering and Legal (20%) $3,393,000 Project Costs $20,356,000 3.3.2.2 Operating Costs Annual operating costs were developed for electrical, labor and maintenance costs for both future AA (FAA) and current AA (CAA) conditions. Table 3-10 shows these costs for the conditions. Operating costs are based on: 24 hour per day, 7 days per week operation Natural gas cost of $4.50 per million Btu Revenue based on 80% of the cost to P&G of producing steam with natural gas in their steam system Labor costs of $24/hour Annual maintenance cost based on 2% of equipment cost and 0.5% of building capital cost Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-9 Table 3-10 Bissell Point Sale of Steam Annual Differential Operating Costs ITEM CAA FAA Revenue from P&G ($531,000) ($623,000) Maintenance $98,000 $98,000 Labor $235,000 $235,000 Total ($198,000) ($290,000) 3.3.2.3 Present Worth Costs Present worth costs for the Bissell Point Sale of Steam alternative are shown in Table 3-11. Total present worth costs are based on: Evaluation period: 20 years Interest rate: 4% Escalation rate: 2.5% Current conditions modeled for years 0 to 10, future conditions modeled for years 11 to 20 Table 3-11 Bissell Point Sale of Steam Alternative Present Worth Costs ITEM COST O&M PW $5,739,000 Steam Sale ($9,967,000) OPCC $20,356,000 Total $16,128,000 3.3.3 Non-Economic Criteria Table 3-12 has a summary of advantages and disadvantages for the Bissell Point Sale of Steam alternative. Table 3-12 Bissell Point Sale of Steam Alternative Advantages and Disadvantage ITEM SUMMARY Advantages · Recovers waste energy to create renewable energy and provide revenue from steam sales Disadvantages · Substantially more capital cost not justified by annual savings · Adds operational complexity to FBI system 3.3.4 Evaluation and Recommendation The Bissell Point Sale of Steam alternative has substantial capital cost that isn’t justified by the annual cost savings and operating the WHBs will add complexity to the FBI trains. These results are Metropolitan St. Louis Sewer District | BISSELL & LEMAY WWTF FLUIDIZED BED INCINERATORS (12565) BLACK & VEATCH | Bissell Point WWTF 3-10 similar to other energy recovery evaluations in this TM. For these reasons, the Bissell Point Sale of Steam alternative is not recommended. To accommodate the option for adding energy recovery in the future, it is recommended that the system is configured such that take-off duct is included for re-routing of waste heat to a future adjacent building; which would house a waste heat boiler, steam turbine, and steam system (condenser, de-aerators, pumps, water treatment system, etc.). With such a configuration, additional costs are not necessary at this time while still configuring the system to allow for the implementation of future energy recovery systems.