Geothermal Power Plant Design Geothermal Power Plant Design

Presented By:

Tom Ettinger, PEProcesses Unlimited International Inc.

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Presentation OverviewPresentation Overview

1. Geothermal Basics

2. Plant Design

3. Questions

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Worldwide Geothermal Worldwide Geothermal Capacity in MWeCapacity in MWe

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Geothermal BasicsGeothermal Basics

Advantages

• Renewable Resource

• Government Incentives

• Environmentally Friendly

Disadvantages

• Transmission

• Resource Risk

• First Cost

• Base Load

• Low Fuel Cost

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Geothermal BasicsGeothermal Basics

Design Challenges

• Resource Conditions

• Choosing a Site

• How Big to Build the Plant• How Big to Build the Plant

• Choosing a Process

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Geothermal BasicsGeothermal Basics

Plant Types

• Steam (condensing & non-condensing)

• Steam Flash (condensing & non-condensing)

• Binary (air vs. water-cooled)• Binary (air vs. water-cooled)

• Geopressured

• Hypersaline

• Bottoming/Topping

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TURBINE GENERATOR

CONDENSER TO VACUUM SYSTEM

Direct Steam Direct Steam –– Process SchematicProcess Schematic

COOLING WATER

PUMP

COOLING

TOWER

PRODUCTION

WELL

GEOTHERMAL RESOURCE

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Direct Steam Direct Steam –– GeysersGeysers

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Kenya NonKenya Non--Condensing Power PlantCondensing Power Plant

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Flash Flash –– Process SchematicProcess Schematic

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Single Flash Single Flash -- Dieng 1Dieng 1

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Dixie Valley Dual FlashDixie Valley Dual Flash

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Dual Flash Dual Flash -- Brady Power PlantBrady Power Plant

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Flash Plant Design ChallengeFlash Plant Design ChallengeHigh NC Gas ContentHigh NC Gas Content

NCG varies from nil to 6%

• Reduces Steam Turbine Output

• Impacts Condenser Sizing and Design• Impacts Condenser Sizing and Design

• Increases Gas Removal System Size

•• Hydrogen Sulfide (HHydrogen Sulfide (H22S) ContentS) Content

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Mahanagdong Vacuum SystemMahanagdong Vacuum System

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Sulfur Abatement SystemSulfur Abatement SystemIron chelate process converts

H2S to elemental Sulfur

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Binary Binary –– Process SchematicProcess Schematic

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Mammoth 1 BinaryMammoth 1 BinaryFirst AirFirst Air--Cooled Binary 1984Cooled Binary 1984

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Mammoth 2 Binary Mammoth 2 Binary

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Binary Plant Design ChallengesBinary Plant Design Challenges

• Heat Exchanger Scaling

• Summer/Winter Capacity

• Safety Concerns

• Wind Direction

• Air Removal

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Geopressure ProcessGeopressure Process

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Texas Geopressured ProjectTexas Geopressured Project

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Salton Sea HypersalineSalton Sea Hypersaline

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Salton Sea Topping TurbineSalton Sea Topping Turbine

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Plant DesignPlant Design

Thermal Efficiency Versus Cost ($/kW)

• Multiple Flashes

• Heat Exchange Area

• Binary Process Fluid• Binary Process Fluid

• Equipment Types

• Free Flowing Wells versus Pumped Wells

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Dual FlashDual Flash

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Steamboat Geothermal Heat ExchangersSteamboat Geothermal Heat Exchangers

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Axial Flow Steam Turbine RotorAxial Flow Steam Turbine Rotor

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Radial Inflow Turbine WheelRadial Inflow Turbine Wheel

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FreeFree--Flowing WellFlowing Well

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Pumped WellsPumped Wells

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Questions?Questions?

Mahanagdong GeothermalMahanagdong Geothermal

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