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Water at 120 c

  1. May 11, 2010 #1
    hello guys
    how can i have liquid water at 120 c ?????????
     
  2. jcsd
  3. May 11, 2010 #2

    phyzguy

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    The boiling point of water is a function of pressure. At pressures above 1 atm, water will remain liquid at temperatures above 100C. At the bottom of the ocean, there are places where liquid water is 300C or even hotter. Nuclear reactors use liquid water above 500C. Have you ever used a pressure cooker?
     
  4. May 11, 2010 #3
    so how can i increase the pressure of water ??
     
  5. May 11, 2010 #4
    and if i have a system with two small heaters immursed in water and i need the water to be liquid at 120 or 130
    if my system only consist of those heaters then i will have steam
    and if i use a pump to pump the water to my system it will pump steam ???
    so how can i make good design to this system ??
     
  6. May 11, 2010 #5

    phyzguy

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    Well, a pressure cooker works by just sealing a vessel so that the steam can't escape, then the steam itself pressurizes the vessel as you heat it. Or you can use a pump to pressurize the vessel - this is what is done in a nuclear reactor. Whether the pump pumps liquid or gas depends on what the pump is designed to do. Be careful!! Pressure cookers can explode if the pressure exceeds what the vessel is capable of withstanding!!
     
  7. May 11, 2010 #6
    thanks man but
    what will happen if i pump pressurized water to the heaters ??????
    sure i know the point of explosion so i will use safety valve
     
  8. May 11, 2010 #7

    phyzguy

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    I don't know how to answer your question. What do you mean, "What will happen?" What are you trying to build?
     
  9. May 11, 2010 #8
    i am trying to build a system produces water at 120
    i mean by the term what will happen that
    whats the effect of the pump on the water reaching the heaters ??
     
  10. May 11, 2010 #9

    phyzguy

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  11. May 11, 2010 #10
    so tell me how can i make a system from
    1- pump
    2- heater
     
  12. May 11, 2010 #11

    phyzguy

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    Sorry, I can't design a system for you. I'm going to bow out. Good luck.
     
  13. May 11, 2010 #12
    This really depends on WHY you want water at 120C. ie the application. It also depends on what quality you need (the liquid vapour ratio).
     
  14. May 11, 2010 #13

    jack action

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    To have liquid water at 120°C you must pressurized it, you can't get out of it.

    Here's a copy of the http://www.engineeringtoolbox.com/saturated-steam-properties-d_101.html" [Broken]. The first column is the absolute pressure, the second is the temperature at which water will boil at that pressure. As you can see, at atmospheric pressure (101,33 kPa), water boils at 100°C. To keep it liquid at 120°C, you must increase pressure to at least 200 kPa (so around 100 kPa gauge pressure).
     
    Last edited by a moderator: May 4, 2017
  15. May 11, 2010 #14

    mheslep

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    For pure water under standard atmospheric pressure, the boiling point is 100 deg C. Dissolving some other compound in water, such as salts, will elevate the boiling point of the resulting solution. Google "boiling point elevation" for details. The maximum temperature elevation with salts is typically limited by the amount that can be dissolved, ie the saturation point.

    Ethylene glycol, aka antifreeze will get you to 120C, but requires 80% glycol.
    http://en.wikipedia.org/wiki/Ethylene_glycol
    http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/boilpt.html
     
    Last edited: May 11, 2010
  16. May 11, 2010 #15

    russ_watters

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    You're going to have to go into a lot more detail about what you are trying to do if you want us to be able to help you. Could you draw/post a diagram of the system you are trying to build?
     
  17. May 12, 2010 #16
    ok guys i will explain my idea to you
    now at my work i have a machine thats used to push the fusible pvc on some aluminium materials , and this aluminium is heated to a temp above 100 c
    so pvc needs heat more than 100 and less than 140 to ensure that pvc will stuck on the alominium
    and thats is done using a small machine which gives water at 130 or 120 to give the required heat to the pvc aluminium pieces
    so all i want to do now is understanding how this unit work ????
    it consists of many thermostatic valves , 2 electric heaters , water pump and many connections
    so the main problem to me is how to make water pressurized ??
    if the pump pumps water to the tank which contain the heater the water will be discharged at atm pressure how can i pressurized water /??????
     
  18. May 12, 2010 #17

    MATLABdude

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    Unfortunately, as soon as the water is no longer pressurized (like when you dispense your 120C water to atmospheric pressure) it will very quickly become steam (albeit, steam at 100+C)

    Given your description above, can you just use an oven heated to 120C instead?
     
  19. May 12, 2010 #18

    mheslep

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    Why does your fluid need to be water? Why not a fluid with a higher boiling point? Oil?
     
  20. May 12, 2010 #19
    you could heat sand in an oven and pour it into your pvc pipe, that would get you the necessary temp and wouldn't have the disadvantages of a steam/water system.
     
  21. May 13, 2010 #20

    FlexGunship

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    Geeze... do I have to do everything?

    - Use DOT3 brake fluid

    Done. It is roughly as viscous as water, has no corrosive properties. Should be fine.
     
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