Process Modeling and Mass Balance Analysis using KBC WaterTracker ® Software for Wastewater...
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Transcript of Process Modeling and Mass Balance Analysis using KBC WaterTracker ® Software for Wastewater...
Process Modeling and Mass Balance Analysis using KBC WaterTracker® Software for Wastewater Discharge Improvements and Water Conservation at a Colorado Sugar RefineryPresented by Ray Hamilton, PE, BCEE
AMEC Environment & Infrastructure Inc., Denver, CO
April, 11, 2014
PWO Industrial Wastewater
SeminarGolden, CO
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Outline
History of Sugar Refineries in ColoradoOverview of Sugar ProcessingExisting Wastewater Disposal SystemNew Regulatory EnvironmentMass Balance Model DevelopmentExisting System for CalibrationProposed System
Summary and Questions
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Sugar Refineries in Colorado
Colorado “Sandwiched” Between Utah and Nebraska1890s - Sugarbeets grown in Colorado shipped to Utah or Nebraska for processing1899 – Colorado’s first sugar refinery opened in Grand Junction
Early Colorado Plains Sugar Refineries1900 – Rocky Ford and Sugar City in the Arkansas River valley of SE Colorado
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Sugar Refineries in Colorado (cont.)
Production Moves to the Front Range1901 First Front Range sugar refinery opens in Loveland1903 new sugar refineries in Windsor and Greeley1904 Fort Collins and Eaton1905 Sterling and Brush1906 Fort MorganBoom and Bust leads to 23 Colorado sugar refineries
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The Sugarbeet
Sugarbeet has Three PartsCentral Root – stores sugarTaproot – supplies moisture and mineralsTop – Photosynthesis provides energy
Sugar in Two FormsMonosaccharide sugar, C6H12O6
disaccharide sugar C12H22O11
Ideal Beet is 2 Pounds and >17% Sugar
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Composition of a Typical Sugarbeet
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The Sugar Refining Process
Beet WashingRemoves dirt and other field debris
SlicingProduces “cossettes”
DiffusionHot water soaking produces “juice”Still contains other beet products and impurities
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The Sugar Refining Process (cont.)
Liming and PressingHigh pH precipitates impuritiesFiltration separates impurities
Recarbination and FiltrationLowers pHRemoves dissolved limePrecipitates calcium carbonateSecond filtration removes calcium carbonate
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The Sugar Refining Process (cont.)
Acidification and FiltrationSulfuric acid to balance and bleachThird filtration produces “standard liquor”Sugar content of standard liquor + 50%
Evaporation and CondensationSeries of evaporators to drive off waterCondensers cool and recycle water
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The Sugar Refining Process (cont.)
CrystallizationSuper saturated solution put under vacuum to crystallize sugar
SeparationCentrifuge spins out sugarFiltrate is “molasses”Purified sugar dried and packaged
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Typical 1900 Era Sugar Refinery
Source: Silver Wedge: The Sugar Beet Industry In Fort Collins, SWCA Environmental Consultants, 2003
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Wastewater Discharges at Sugar Refinery
Major Sources of WastewaterMud from beet washingCondenser waterPressed calcium carbonateBoiler blow-down to ash pond
Historic Discharge to Unlined PondsEvaporation and seepageIntegral part of water rights adjudication
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Typical Flow Patterns at Sugar Refinery
Campaign Driven – September to April
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Regulatory Concerns
Discharge to GroundwaterGroundwater standards apply
Total coliform standard – as if water supplyHigh Mn++ levels in ashSource well water above TDS standardPotential nitrite/nitrate problems
Pond Seepage to South Platte River Alluvial FlowWater Rights Issues Ignored
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Regulatory Concerns (cont.)
CDPHE Applied Surface Water Standards to Groundwater DischargeSouth Platte River standards
EC/TDS/SAR limits controlled by downstream bean farmers
New ammonia limits
Measured as Weighted Average of In-Pond Values and Pond Influent FlowsSeepage does not equal influent - biasing mass
based parameters (BOD5 and TSS)No credit for effects of filtering through pond bottom
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Client Concerns
Water RightsHigh Cost of TreatmentLow Hanging FruitPCC Press eliminated all liquid discharge to PCC pondMud Press significantly reduces flow to mud pond
How Much More Can be Saved with Water Recycling and Water Conservation?
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Mass Balance Approach
Simplest Mass Balance
Unfortunately It’s not that Simple
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Mass Balance Inputs – External to Process
Beets:Sugar, TDS, TSS, N, H2O
Water Supply (wells and ditch):TDS, N-NO3, H2O
Stormwater/Snow Runoff:TDS, TSS H2O
Coal:TDS, TSS, N, S, Mn
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Mass Balance Inputs – Internal to Process
SO2 and Sulfamic Acid:S, TDS, N
GypsumTDS, S
Limestone, Soda Ash & CausticTDS, TSS, S
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Mass Balance Outputs
EvaporationMud, condenser, and ash pondsGranulator drier
SeepageMud, condenser, and ash ponds
DischargeFlue gasPressed mud
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Mass Balance Outputs (cont.)
ProductsProcessed SugarMolassesPressed PCC (animal feed byproduct)
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Mass Balance Software
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WaterTracker Top Level View
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WaterTracker Process Level View
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Recycle Alternatives Modeled
Separate Fly Ash from Bottom AshClosed Loop Condenser Circuit with
Cooling Tower Mud Press EnhancementsInternal Redirection of Process and
Waste Streams
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Results of Water Recycling and Conservation