Date post: | 26-Jan-2015 |
Category: |
Engineering |
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Boiling Water Using the Sun Water Chemistry Challenges for a
Solar Power Plant
Jeanette Shoemaker, P.E. (Ohio)
Senior Mechanical Engineer
Bechtel Power Corporation
CIVIL GOVERNMENT SERVICESMINING & METALSOIL, GAS & CHEMICALS POWER
Ivanpah Solar Electric Generating Facility
Overview
Thermal Solar Power Fundamentals
Water Chemistry
Challenges for Solar Power Plants– Water Availability– Water Treatment Options– Wastewater Discharge
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Ivanpah Solar Electric Generating Facility
© Bechtel | 3
Located in CA ~45 miles southwest of Las Vegas Owned By: NRG Energy, Google and BrightSource Energy 3 Units totaling approximately 400 MW Project site over 3600 acres Approximately 173,500 heliostats (each with having 2 mirrors) 459-foot steel structure
– Solar receiver steam generator (SRSG) sits atop tower– Auxiliary equipment located within the tower
Solar Thermal – Power Tower Technology
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Water Chemistry
What are the water quality requirements?
• High-Purity• Deoxygenated• pH Controlled
Why is it important?
Damage to the turbine or SRSG from:• Deposition• Erosion• Corrosion
Parameter SRSGMakeup
Drinking Water
Chloride 0.003 ppm 250 ppm
Specific Conductivity
0.2 μS/cm NR
Copper 0.002 ppm 1.3 ppm
Iron 0.005 ppm 0.3 ppm
pH 9.2 – 9.6 6.5 – 8.5
Silica 0.01 ppm NR
Sodium 0.003 ppm NR
Sulfate 0.003 ppm 250 ppm
TDS 0.025 ppm 500 ppm
Dissolved Oxygen
< 0.007 ppm 6 – 9 ppm
NR = Not Regulated
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Water Chemistry Challenges
Challenge: Zero Liquid Discharge
• Limited Water Availability
• No Evaporation Ponds or Onsite Waste Discharge Options
Impacts:
• Need water to make power
• Mirrors require frequent cleaning for best performance
• Water consumption and waste generation from water treatment technologies
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Minimizing Water Consumption
• Utilize ‘dry cooling’ in lieu of cooling towers
• Air-Cooled Condenser requires no water supply
• Optimize mirror washing process to reduce frequency and minimize water consumption
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Water Treatment
• Limited Water Quality Data• Technologies Available:
• Reverse Osmosis (RO)• Membrane separation• Large waste/reject stream generated
• Ion Exchange (IX)• No waste stream generated from process• Frequent regeneration required
• Ultrafiltration (UF)• Used in combination with ion exchange or RO
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Wastewater Management
• Restrictions
• No evaporation ponds
• All wastewater must be recycled or shipped off-site
• Results
• Strict water management• Reduce water consumption
• Reuse process water to maximum extent
• 100% recycle of all waste streams
• Waste-minimizing treatment technology
• IX in lieu of UF/RO
• Offsite resin regeneration• Trailer – mounted rental equipment
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QUESTIONS?