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AggiE -Challenge: Nuclear Desalination Fall 2013

AggiE -Challenge: Nuclear Desalination Fall 2013. Overview. Problem Statement Economics Nuclear Reactor Design Desalination Plant Technologies The Next Step. Problem Statement:. Design a water desalination plant Conditions: Energy will be provided by a nuclear plant

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AggiE -Challenge: Nuclear Desalination Fall 2013

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  1. AggiE-Challenge: Nuclear DesalinationFall 2013

  2. Overview • Problem Statement • Economics • Nuclear Reactor Design • Desalination Plant Technologies • The Next Step

  3. Problem Statement: • Design a water desalination plant • Conditions: • Energy will be provided by a nuclear plant • Plant will utilize thermal vapor-compression desalination (jet ejector technologies) • Plant must be able to supply fresh water to a large city (10 to 12 million people) • Questions: • What size, design and type of nuclear reactor will be the most effective? • What is the most efficient scheme of water desalination? i.e. number of jet ejectors, additional collection means, etc. • Is it cost effective to produce electricity in addition to water?

  4. Steam from Nuclear Reactor • New Steam • Gas/Liquid Mixture • Motive Steam (Superheated) • Entrailed Steam • Salt Water • Product Steam • Fresh Water (Recycle and Product) • Electricity Nuclear Reactor Power Grid Desalination Plant Heat Exchanger Jet Ejectors Multi effect Evaporators Brine Fresh Water Turbine Separator Fresh water storage tank Ocean or other salt water source

  5. Economics of Water and Electricity Tech/Econ Team Michael Bynum TaufikRidha Garrett Steiger Emily Wilborn Jennifer Sakowski Jayci Blake Alexis Musso Preston Phillips Mary Catherine Whitney

  6. Location: Los Angeles, California • Considering: • Wholesale price of water and electricity • Water: $0.0235/ft3 (U.S. Energy Information Administration) • Electricity: $39.09/MWh(Olivenhain Municipal Water District) • Necessity for clean water • Desperate due to growing population and depletion of Colorado river • Proximity to salt water source • The Pacific ocean is huge and very nearby • Opinion towards nuclear energy • Not best friends, but cooperating associates out of desperation for clean water

  7. Electricity vs. Water • Ratio of water to electricity heavily dependent on local necessity and potential profits • These data are based on a single jet ejector system, with superheat not including the multi effect evaporator

  8. Nuclear Reactor Design Nuclear Team Jenni Beetge Hanniel Jouvain N. Honang Terrell Hughes Ayaz Merchant Shiv Venkatasetty

  9. Outline • Nuclear Technology Motivation • Site and Reactor Recommendation • Steam Generators • Plant Simulation Programs • Plant Integration • The Next Step

  10. Nuclear Technology Motivation(Economic Incentives) • Fluctuation in natural gas prices • Normal operation of a nuclear power plant is not harmful to the environment • No carbon emissions • Power plant life cycles predicted to reach 60+ years

  11. Economic Incentives Energy Information Administration- U.S. Department of Energy

  12. Site and Reactor Recommendation • Diablo Canyon Nuclear Power Plant • Along Californian coast, near LA • 2 Pressurized Water Reactors: • 3360 MW(th) each • 2240 MW(e) total; ~6720 MW(th) • Operational since 1985 • Due for license renewal 2024 • Modifications provide opportunity for technology integration • Drawback: significant electricity supplier to CA Diablo Canyon Plant LA

  13. Diablo Canyon nuclear power plant is a PWR from Westinghouse Corporation.

  14. Nuclear Team Perspective turbine Steam generator condenser Jet injector Desalination plant

  15. Plant Simulation ProgramsFrom: International Atomic Energy Agency • DE-TOP: Desalination Thermodynamic Optimization Program • Limited Functionality • DEEP: Desalination Economic Evaluation Program • Results: • Incremental economic estimate for addition of intermediate loop to the system • Comparison of RO, MED Vapor Compression, MSF and base case (electricity only)

  16. DEEP Schematic Diagram

  17. DEEP, cont. MSF RO+MSF MED RO RO+MED

  18. Integration of the nuclear and desalination plants • Problem Feeding water back into the secondary loop requires modification of existing structure, which causes safety and license compatibility issues • Solution Additional heat exchanger between the secondary coolant and the motive steam • According to DEEP model, water cost for sample MED VC increases ~$0.06/m3 = $0.22/kgal • LA wholesale price of water is $3.14/kgal

  19. Steam Generator Analysis Steam generators: Heat exchangers used to convert water into steam from heat produced in a nuclear reactor core. Advantage: The radioactive water/steam never contacts the turbine or other element in the secondary loop

  20. Denting: Caused by buildup of corrosive material in the space between the tube and the plane • Fatigue cracking: Caused by tube vibration • Fretting: Wearing of tubes in their supports due to flow induced vibration • Pitting: local breakdown in the protective film on the tube • Tube wear: Thinning of the tube caused by contact with support structures either as the tube vibrate or as feed water entering the vessel Heat exchanger failures in nuclear plants

  21. Not accommodating for failures is costly and expensive

  22. Steam Generator Recommendation Include an extra steam generator to accommodate for any upcoming failures in the desalination plant.

  23. Desalination Plant Technologies Tech/Econ Team Michael Bynum TaufikRidha Garrett Steiger Emily Wilborn Jennifer Sakowski Jayci Blake Alexis Musso Preston Phillips Mary Catherine Whitney

  24. Outline • Turbine • Jet Ejectors • Superheat • Multi Stage Jet Ejectors • Multi Effect Evaporator • Summary • Future Work

  25. High Pressure Turbine • Use high pressure turbine to take some of the energy from the steam to produce electricity • Supplement the desalination plant and the nuclear reactor • Sell back into the grid • Depending on location selling electricity may be more profitable than water • Makes plant more versatile http://telegraphgh.com/uploaded/pictures/engine_steam_turbine.gif

  26. Determining Power Production and Desalination Capacity • Goal: Determine the amount of water that can be desalinated and the amount of power that can be produced to evaluate the effect of different operating conditions • Process for a single stage: • Specify: • Mass flow rate of working steam • Steam turbine inlet conditions (Sat. steam at ~1250 psia) • Steam Turbine Discharge Pressure (vary) • Steam turbine efficiency (80%) • Determine the power production

  27. where η= turbine efficiency Plus 1 mass balance to determine the vapor fraction Power Production

  28. Determining Power Production and Desalination Capacity • Goal: Determine the amount of water that can be desalinated and the amount of power that can be produced to evaluate the effect of different operating conditions • Process for a single stage: • Specify: • Mass flow rate of working steam • Steam turbine inlet conditions (Sat. steam at ~1250 psia) • Steam Turbine Discharge Pressure (vary) • Steam turbine efficiency (80%) • Determine the power production • Determine the desalination capacity • Jet Ejector calculations – mass flow ratio

  29. Jet Ejectors • Low maintenance devices, requiring no moving parts, that can be easily replaced or repaired • Uses a fast moving “motive” stream of steam to evaporate fresh water out of a supply of salt water or brine • Driven by an enthalpy difference between the inlet and outlet nozzle Motive Stream Product Stream Entrailed Stream http://www.primetechrkg.com/images/steam_jet_ejector.jpg Fresh Water Brine

  30. where η = nozzle efficiency ΔH = Enthalpy drop across the nozzle where = Dimensionless Group Mass Flow Ratio

  31. Mass Flow Ratio

  32. Power vs. Desalination Capacity (Single Stage)

  33. Superheat • Steam from the turbine is superheated before being sent through the jet ejector • Adding 50 degrees of superheat to the motive steam increases the mass flow rate on average 50%

  34. Multi Stage Jet Ejectors • Jet ejector system where multiple jet ejectors are used in a series of stages to gradually increase the concentration of the waste brine • For a ten stage jet ejector, efficiency (distillate mass per amount of motive steam) increased by an average 15% depending on the turbine discharge pressure • Assuming each jet ejector is the same size

  35. Multi Effect Evaporator 5 lbm water vapor produced per effect • Part of the steam from the jet ejector exhaust is diverted to a multi effect evaporator to squeeze the last bit of energy out of the motive steam and produce more fresh water • Multi effect evaporator example: Effect n: 14.7 psia Effect 2: 100 psia Effect 1: 120 psia Fresh water Brine Fresh water Brine Fresh water Brine From product stream of jet ejector Enter: 5 lbm steam at 120 psia Salt water Source Fresh water Storage 5 lbm fresh water produced per effect Total fresh water produced = 5+5+(5*n) lbm

  36. Multi Effect Evaporator • Example calculations for a ten stage multi effect evaporator • Multi effect evaporators allow for the most economical use of the remaining energy from the jet ejector product steam • 120 psia: 17920 Btu/(h*ft2*F)

  37. Summary

  38. The Next Step: Spring 2014 • Simulate the plant or segments of the plant for technical and economic feasibility • Using ASPEN, MATLAB, DEEP • Co-generation decision: Pending • Future Research…

  39. Future Research (1) • Find the most efficient number of jet ejector stages • Calculated by the increase in distillate mass per amount motive steam • Find the most efficient turbine discharge pressure • Based on the most efficient number of stages • Consider producing electricity to maximize profits • Calculate the most efficient jet ejector sizes and the sizes for each stage • Inlet and outlet nozzle diameter, length • May be different for each stage http://images.engineeringnet.eu/RSS/feeds_P-mag/images/steamjet2.jpg

  40. Future Research (2) • Interpolation from the existing dimensionless group is only valid if the operating pressure is at atmospheric pressure. • If operating pressure > atmospheric, the deviation must be accounted for before interpolation. (Momentum Ratio)arb=(Momentum Ratio)ref+(Momentum Ratio)ref·(Momentum Ratio)dev

  41. Future Research (3) • Calculate the most cost efficient number and size of effects • Consider heat exchanger size, material, cost • Each effect may be different • Calculate cost of the entire multi effect system • Is it a cost efficient system? http://www.redaspa.com/wp-content/uploads/2013/04/UP_10-11-11_8lkPe8.jpg

  42. Future Research (4) • Research different locations to maximize profits • In depth analysis of plant costs and profits including: • Cost of nuclear reactor, turbine, jet ejectors, multi effect evaporators and other associated plant costs • Full analysis of profits, how long it will take to recover from startup costs etc. http://deathandtaxesmag.wpengine.netdna-cdn.com/wp-content/uploads/2011/11/Stacks-of-money-pictures-3.jpg

  43. http://sd.keepcalm-o-matic.co.uk/i/thank-you-for-your-attention-any-questions-24.pnghttp://sd.keepcalm-o-matic.co.uk/i/thank-you-for-your-attention-any-questions-24.png

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