A New Generation of Molten Salt


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Yara research has identified a new grade of potassium calcium nitrate that can reduce costs and improve performance in concentrated solar power (CSP) plants. Following positive laboratory testing, this new project is ready to change heat storage in the global solar market.

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A New Generation of Molten Salt

  1. 1. A New Generation of Molten Salt 14th November 2012 Sevilla, Spain Emilio Iglesias Sola Yara International ASA Infanta Mercedes,31 28020 Madrid Tfno: 91 426 35 00 Fax: 91 745 14 62 Mobile: 00 34 617 46 21 32 http://www.yara.es http://www.yara.com
  2. 2. Yara – the Global Leader in Nitrates Founded in 1905, over a century of nitrogen chemistry expertise Production Scale: – Global No.1 in Nitrates production (Different grades) – Global No.1 in NPK fertilizers production – Global No.1 in Calcium Nitrate production Logistics Reach: – 200 warehouses and terminals worldwide, – sales in 150 countries Research: Continuous nitrogen chemistry R&D Headquartered in Oslo, Norway
  3. 3. Solar Thermal market demands improved molten salts forheat storage and heat transfer Benefits of using molten salts for heat transfer and storage • Avoid Thermal oil (expensive, environmental challenges) • No need for expensive heat exchangers • Avoid temperature losses in the exchangers • Wider Delta Tª: • Less molten salts needs • New turbines coupled • Better energy yield/efficiency Benefits of using molten salts for heat storage (alone) • Cost reduction (cost of molten salt). • Potassium and Sodium price increase trend • Lower melting point: • Avoid potential blockages • Wider Δ Tª
  4. 4. Yara has the Nitrates expertise Yara produces several CN grades and formats Existing literature regarding Calcium Nitrate use in solar thermal power Yara researched and tested to identify a nitrate grade with the optimal thermal performance: Scope of research on thermal properties of several CN grades (non-exhaustive list) • Cp. Specific Heat Capacity • Thermal decomposition • Eutectic mixture behavior • Melting point • Corrosion tests • Heat of fusion • Physical melting process • Enthalpy of dehydration • Viscosity and density • Thermal conductivity
  5. 5. Next Generation eutectic molten salt solution from theworldwide leader in nitrates Solar Thermal Market Need for Improved Heat Transfer and Storage Potassium Research & Calcium Innovation Nitrate (CN-K) Comprehensive laboratory Yara testing at Universidad Complutense Nitrate de Madrid Leadership KNO3 5Ca(NO3)2 10H2O
  6. 6. Advantages of Eutectic ternary molten salt using CN-KNaNO3 KNO3 KNO3 5Ca(NO3)2 10H2O 15 % 38 % 56 % 38 % 5% 42 % 15 % 43 % 42 %NaNO3 KNO3 Ca(NO3)2 Yara’s new KNO3 5Ca(NO3)2 10H2O is:  Synthetic  Chloride-free  Very pure  Competitively priced
  7. 7. Eutectic Molten Salt with CN-K melting process State/Form Temperature (⁰ C) Gas 569 Improvements over binary salts:  Lower melting point Liquid ΔTª: 438  Broader ΔTª 15%NaNO3 43%KNO3  Reduced risk of molten salt 42%Ca(NO3)2 solidification 131 Solid 15%NaNO3 43%KNO3 42%Ca(NO3)2 0
  8. 8. Corrosion tests show eutectic CN-K Molten Salt to besignificantly less corrosive than binary salts Lateral cross-section, SEM Sal binaria Binary salt Ternary salt Sal ternaria 3,0 Oxide layer thickness Oxide layer thickness Oxide layer thickness 2,5 2,0 m/S0 (mg/cm ) 2000 hours 2 1,5 2500 hours 3000 hours 1,0 0,5 0,0 0 500 1000 1500 2000 2500 3000 Tiempo (h) Time (h)
  9. 9. Euctectic CN-K Molten Salt:Performance Benefits & Cost savings in Solar Thermal ElectricityPlant Construction & Operation Lower CAPEX: Yara CN-K scale advantage translates into lower-cost molten salt mix, pushing down solar energy cost Lower melting point: 131 ºC – Wider delta Tª opens new operational possibilities and means you need less of the molten salt blend to generate power – Reduced risk of molten salt solidification: a technical challenge causing plant damage, stoppage and maintenance costs for current molten salt technologies Lower start-up energy costs: Less energy needed to melt the ternary mixture including CN-K Lower life-cycle cost: less corrosive eutectic CN-K molten salt mix reduces maintenance costs