ECS_NB_Chunk_4

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Author:
ChrisC
ID:
78835
Filename:
ECS_NB_Chunk_4
Updated:
2011-04-11 11:05:52
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ECS
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ECS
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  1. What temp and pressure do super critical boilers work above?
    • P>220.9 bar
    • T>374.3 C

    **Efficiency increases with both temperature and pressure.
  2. What are advantages of Super Critical Boiler?
    • 1) High efficiency
    • 2) Lower emissions
    • 3) Lower cost
    • i) Once through is simpler
    • ii) No drum
    • iii) Smaller diameter tubes
  3. Give 3 reasons why CFB is better than PC for SCB?
    • 1) For CFB highest heat flux region is in the water heating section.
    • 2) For PC highest heat flux is near water-steam transition region.
    • 3) Highest heat flux is much higher than average in PC.
    • 4) Much more uniform heat distribution
  4. In a gas turbine what happens to efficiency as pressure ratio increase?
    It increases in a logarithmic fashion.
  5. What two types of gasification are used for IGCC?
    • 1) Air blown - 0.5 heating value of O2 blown
    • 2) Oxygen blown - Much better for CO2 capture as flue gas is only CO2 and H2O
  6. What are benefits of IGCC (4)?
    • 1) Low emissions
    • 2) High efficiency
    • 3) Best for CO2 capture
    • 4) Can produce H2
  7. Give some barriers to IGCC deployment.
    • 1) PC can meet current standards
    • 2) IGCC financing costs are higher
    • 3) No reward for risk taking
    • 4) Bottle neck construction
    • 5) More project planning
  8. Rank types of gas turbine cycles by efficiency.
    • Simple cycle (36.4%)
    • Combined cycle (52.7%)
    • Co generation cycle (85.1%)
    • Combined cycle with Cogen (89.3%)
  9. What are some ways to meet zero emission technology?
    • 1) In-situ carbon capture (oxygen firing and chemical looping)
    • 2) Gasification systems (e.g. IGGC)
  10. What was the US zero emission project?
    • Futuregen
    • Annouced by bush in 2003
    • in 2007 Mattoon Township
    • in 2009 funding was pulled
  11. What are some benefits for vertical axle wind turbines?
    • 1) Independent of wind direction
    • 2) Low rotational speed (Torque up, Power down)
    • 3) Mechanical components are on ground level for easy access.
    • 4) Expensive tower is not required.
  12. What is the betz limit?
    • 0.5926
    • Theoretical maximum efficiency
  13. What is the ideal tip speed ratio for 2 and 4 blades?
    • 2 blades (5)
    • 4 blades (3)

    **Efficiency increase with number of blades but noise increase with tip speed ^5
  14. What are the components of the wind turbine?
    • Hub height - Height to middle of props
    • Blade
    • Gearbox and generator - Found in hub
    • Swept blade area
    • tower
  15. What are general cut in and out speeds?
    • Cut in 7-10mph
    • Cut out 45-80mph
    • Rate speed 25-35mph (where design power is found)
  16. What are the parts of a hydro turbine?
    • 1) Spillway - Release water downstream that is not used to make energy
    • 2) Penstock - Collects water from upstream leading it to turbine
    • 3) Draft tube - Passage directly below turbine
    • 4) Tailrace - Passage from draft tube downstream
    • 5) Surge tank - Reservoir that vents sudden pressure build up if required.
    • 6) Intake - Leads to the penstock
    • 7) Reservoir - Upstream water source
  17. What are the types of turbines?
    • 1) Reaction (Static pressure changes)
    • Converts both flow and kinetic energy
    • Axial flow - Kaplan
    • Radial or mixed flow - Francis
    • 2) Impulse (Static pressure is constant)
    • Converts only kinetic energy
    • Tangental bucket flow - Pelton
  18. What is Kaplan used for?
    • 1) Very low head
    • 2) High volume flow
  19. For differnt turbines what are the specific speeds (non-dimensional)?
    • Axial Flow 7-14
    • Mixed flow (Francis) 3.5-7
    • Centrifugal or radial flow (Francis) 1-3.5
    • Impulse (Pelton) 0-1
  20. Random facts about micro-hydro.
    • 1) Typically produce up to 100kw power
    • 2) 2000MW installed in Canada
    • 3) 40 in NS supplying 11% of provincial capacity
  21. What are the things that must be taken into account in LCA?
    Material extraction, Material Production, Product manufacture, Distribution, Retail, Use, Disposal

    **There is also transportation throughout
  22. What are the steps of LCA?
    • 1) Goal and scope definition
    • 2) Inventory analysis
    • 3) Impact assessment
  23. What are the applications of LCA for companies?
    • 1) Product development and improvement. (Product comparison)
    • 2) Strategic planning (Product assessment)
    • 3) Public policy making
    • 4) Marketing (Eco-Labeling)
  24. What are the applications of LCA for comsumers?
    • 1) Product comparison
    • 2) Product assement
    • 3) Eco-labeling
  25. What are some global warming potentials?
    • CH4 - 25
    • N2O - 298
    • HFC - 124-12800
    • PFC 7000-12000

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