What type of gas ?

Discussion in 'Motorhome Chat' started by Snitrats, Feb 26, 2013.

  1. Snitrats

    Snitrats Funster

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    Just curious,When you fill your refillable gas cylinders with auto-gas, what is it , propane , butane or some sort of cocktail
     
  2. Snowbird

    Snowbird Funster Life Member

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    From what I can gather its a cocktail of both, but it does not freeze like butain.
     
  3. Roryboys Dad

    Roryboys Dad Read Only Funster

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    Wikipedia -

    [​IMG][​IMG]
    A Shell Autogas refuelling station.


    Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.
    Autogas is widely used as a "green" fuel, as it decreases exhaust emissions. In particular, it reduces CO2 emissions by around 35% compared to petrol. One litre of petrol produces 2.3 kg of CO2 when burnt, whereas the equivalent amount of autogas produces only 1.5 kg of CO2 when burnt. It has an octane rating (MON/RON) that is between 90 and 110 and an energy content (higher heating value—HHV) that is between 25.5 megajoules per litre (for pure propane) and 28.7 megajoules per litre (for pure butane) depending upon the actual fuel composition.

    :france::france::france:
     
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  4. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    In the UK it is almost all propane, other european countries mix propane/butane at various mix levels depending on time of year.

    For the record the problem with butane is not that it "freezes" but that its boiling point is close to zero C. The gas is stored under pressure in the cylinder in liquid form (propane at 6 bar/100psi aprox and butane at 2 bar/28 psi aprox). Propane's boiling point is minus 42 C so will produce gaseous vapour in very cold temperatures, butane's boiling point being close to 0C means that when it gets dow to around that temperature it ceases to turn into gaseous vapour.

    D.
     
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  5. Gromett

    Gromett Funster

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    that looks way wrong by a magnitude to me. did they mean micrograms? or even grams?

    1Ltr of petrol weighs about 0.7 KG so how can it produce 2.3KG of CO2?

    1Ltr of LPG weighs aprox 500g so how can it produce 1.5KG of CO2?

    Not looked up the actual figures but these look totally wrong on first glance although the ratio between LPG and Petrol could well be right.
     
  6. Gromett

    Gromett Funster

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    I have just looked it up. I was wrong you were right.. :Doh::Doh::Doh:

    I didn't think it through. It is combining oxygen from the air with carbon from the fuel and O2 in in the CO2 weighs 2 times as much..

    Sorry, and thank you for my lesson for today. I love learning new stuff.:thumb::thumb::thumb::BigGrin:
     
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  7. scotjimland

    scotjimland Funster Life Member

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    yes, it does look odd ... but actually correct...

    googling came up with several sites giving the formula for calculating.. here is one..

    http://www.bicyclinginfo.org/faqs/answer.cfm?id=3460

    and another

    http://www.stewartmarion.com/carbon-footprint/html/carbon-footprint-car.html


    EDIT

    just noticed you had posted while I was googling
     
    Last edited: Feb 26, 2013
  8. Gromett

    Gromett Funster

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  9. cmcardle75

    cmcardle75 Read Only Funster

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    UK autogas is about 92% propane, 8% butane. Further south, they'll stick more butane in as it is cheaper per kWh. Butane doesn't vaporise in a northern european winter.

    Christian.
     
  10. oldun

    oldun Read Only Funster

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    I don't believe that there is anywhere on earth where butane would freeze.

    At temperateures nearly 0C it stops gassing off (evaporating) making it useless at low temperatures.

    However the liquid remains liquid - it never freezes.
     
  11. Gromett

    Gromett Funster

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    The end effect is the same though :Wink:
     
  12. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    Quite correct, butane freezing/melting point is minus 140 deg C! See my previous reply.

    D.
     
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