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LNG heat value question?

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  • 300mileclub
    replied
    Speaking of rockets. archived Houston Command logs from Apollo 11 - rebroadcast on the 50th anniversary of the Moon landing - show 5,000 lbs/min of propellant (2 min burn) were used to leave moon orbit and head back to Earth. Comments from the crew say the burns - landing; launch; leaving orbit to head to Moon and to head back - were silent . . in contrast to the same shots in the movie Apollo 13.

    https://apolloinrealtime.org/11/

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  • 300mileclub
    replied
    SpaceX test-fired a high thrust methane rocket motor 4 Feb 2019 called the Raptor at the company test site in McGregor TX. A total of seven of the motors will power their Starship upper stage to the Moon and, later, to Mars with 31 motors used in the Super Heavy booster that carries the Starship into space.

    The company claims that methane gives better performance than the present kerosene motors (used on Russian Soyuz.) SpaceX is already developing high efficiency CO2 capture with H2O to form liquid CH4 (methane) & O2, critical for propellant production on Mars:

    https://www.theverge.com/2019/2/4/18...ull-size-texas

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  • 300mileclub
    replied
    Blue Origin New Shepard space vehicle successfully flew to space before executing a historic landing back at the launch site in West Texas in 2015:

    https://www.youtube.com/watch?v=9pillaOxGCo


    Blue Origin is developing rocket motor fueled with LNG:

    The BE-4 uses oxygen-rich staged combustion of liquid oxygen and LNG to produce 550,000 lbs. of thrust. LNG is commercially available, affordable, and highly efficient for spaceflight. Unlike other rocket fuels, such as kerosene, LNG can be used to pressurize a rocket s propellant tanks. This is called autogenous pressurization and eliminates the need for costly and complex pressurization systems, like helium. LNG also leaves no soot byproducts as kerosene does, simplifying engine reuse:

    https://www.lngindustry.com/small-sc...t-in-mid-2020/


    https://www.blueorigin.com/engines#be-4


    And, a theme song for the quantum advance for natural gas fuel reported above:

    Im Your Vehicle, Baby - The Ides Of March

    https://www.youtube.com/watch?v=fiLaNEFyCiM

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  • 300mileclub
    replied
    The Shell LNG station at Travel Centers of America 12310 S Highway 33 Santa Nella CA has a liquid nitrogen tank half the height of the LNG tank.

    In all kinds of industries, expendable coolant chambers use cryogenic LN2 (liquid N2) to achieve low temperatures for keeping other things cold. In the case of these LNG stations, nitrogen boils off in the course of cooling the LNG. Nitrogen already makes up over 3/4 of the atmosphere.

    Why is any of this important for vehicles needing CNG? A brief look at the major players putting in LNG stations reveals:

    - BLU LNG re-injects LNG boil-off back into a gas pipeline (interesting, since a LNG station does not need to have natural gas service since pipeline gas is not used to make the LNG)


    - CLEAN ENERGY will add a compressor, storage tubes, and dispenser to supply CNG from an LNG station - sometimes. Photo shows that all the tubes are connected together to work as one, so the compressor must be keeping at least 3600 psi in the tubes. As more LNG boils off, more CNG is added to the storage tubes until the max working pressure is reached - which can be as high as 5500 psi.

    - SHELL is using the LIN-assist cryogenic non-boil off cooling mentioned developed by LINDE mentioned in the above
    04-27-2013, 08:56 PM
    post. At atmospheric pressure, Methane boils at -260F and Nitrogen (N2) boils at -320F. These stations will have a tall LNG tank and a smaller N2 tank.

    Naturally, if LNG is being dispensed regularly into trucks, the boil off situation is avoided.


    http://www.lngworldnews.com/usa-shell-opens-lng-fueling-lanes-in-santa-nella/


    http://www.ngvjournal.com/shell-opens-second-lng-refueling-site-in-california/


    https://www.ta-petro.com/about-us/press-center/945016/travelcenters-of-america-opens-lng-fueling-lanes-at-ta-santa-nella-california


    LNG_gustine_shell_b.jpg LNG_gustine_shell_6.jpg LCNG_CPoint_d.jpg

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  • 300mileclub
    replied
    It seems the rocket industry is well ahead of simply keeping moisture out of a fuel. No mention of the pressures, if any, that are used. Was very surprised when reading this news item because it was thought that SpaceX used the low-tech kerosene used in Russian rockets for reliability and cost reasons (A Soyuz launch is ten times cheaper than what the Space Shuttles missions cost.) When digging further, the Wiki writeup on SpaceX had this gem:

    Musk goes for methane-burning reusable rockets as step to colonise Mars. We are going to do methane, Musk announced as he described his future plans for reusable launch vehicles including those designed to take astronauts to Mars within 15 years. The energy cost of methane is the lowest and it has a slight Isp (Specific Impulse) advantage over Kerosene. And it does not have the pain in the ass factor that hydrogen has.

    SpaceX said it suspected the explosion that destroyed the Falcon 9 rocket on the launch pad in Sept 2016 had something to do with one of three carbon fiber helium tankshttps://www.engadget.com/amp/2016/11...ocket-mystery/

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  • 300mileclub
    replied
    http://www.fleetsandfuels.com/fuels/...m_medium=email

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  • Kuma
    replied
    Re: A "Refer" for perishable goods trucks evolves into "Refers" to keep the LNG cold.

    So, if you don't use it, you loose it, I guess for a truck running all the time it would be OK but doesn't sound like an option for a daily driver.

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  • Amfuel
    replied
    Re: A "Refer" for perishable goods trucks evolves into "Refers" to keep the LNG cold.

    No Kuma, it doesn't work that way. Line gas at your home is 6"- 7" water column (about 1/4 psi) you would overpressure the system with out even thinking about it. Gas meters are not like some electric meters. They don't run backwards. (to my knowledge)

    You could however compress the off gas into storage, but not at home as storage at home is illegal unless it is the fuel tank of a vehicle.

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  • Kuma
    replied
    Re: A "Refer" for perishable goods trucks evolves into "Refers" to keep the LNG cold.

    So when this is parked in the driveway venting off pressure (GNG) can you plug it into your house? will the gas company meter run backwards?
    I use LN2 dewars, when it vents, no big deal, most of the air we breath is nitrogen, another story with methane gas.

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  • 300mileclub
    replied
    for popular sizes, with a heat management system that auto-refrigerates the tank.

    http://www.fleetsandfuels.com/fuels/...m_medium=email

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  • cowboy
    replied
    Re: LNG heat value question?

    ok if you have evaporation say on a hot day you put water on your arm it will cool your arm as the water evaporates the lng evaporates faster as the pressure drops so by pulling vapor when the pressure is high the pressure inside of the tank drops and the lng starts to boil off or evaporate and this causes it to cool the remaining lng to drop the pressure if the pressure gets to low then the regulator will pull liquid and the evporation slows and the liquid starts absorbing heat form the surounding air and the pressure will rise. that is the simple scoop of how it works. there is probley someone here that can explain it better but that is the jest of it

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  • Mannert
    replied
    Re: LNG heat value question?

    I don't quite understand why - If more liquid is pulled, the saturation pressure will increase. Can you explain?

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  • cowboy
    replied
    Re: LNG heat value question?

    two dollar hell thats a hundurd dollar answer but lots of good information

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  • larrycng
    replied
    Re: LNG heat value question?

    Hope these pictures help understand the LNG tank. I have a few more. The vertical bar is the fuel level sender. The space betwen the 2 shells is about 1-1/8 on an inch.

    Larrycng
    Attached Files
    Last edited by larrycng; 03-20-2009, 11:43 AM. Reason: add correct measurement

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  • Franz
    replied

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