Discussion in 'General Conversation' started by Ulikedew, Jan 25, 2008.

  1. Ulikedew

    Ulikedew New Member

    Georgetown IN
    TIPS ON PUMPING GAS (Was sent to me from my aunt where she got it I have no idea)

    I don't know what you guys are paying for gasoline ... but here in California we are also paying higher, up to $3.50 per gallon. But my line of work is in petroleum for about 31 years now, so here are some tricks to get more of your money's worth for every gallon.

    Here at the Kinder Morgan Pipeline where I work in San Jose , CA we deliver about 4 million gallons in a 24-hour period thru the pipeline. One day is diesel the next day is jet fuel, and gasoline, regular and premium grades.

    We have 34-storage tanks here with a total capacity of 16,800,000 gallons.

    Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer gasoline expands, so buying in the afternoon or in the evening....your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role.

    A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.

    When you're filling up do not squeeze the trigger of the nozzle to a fastmode. If you look you will see that the trigger has three (3) stages: low,middle, and high. In slow mode you should be pumping on low speed, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money.

    One of the most important tips is to fill up when your gas tank is HALF FULL or HALF EMPTY. The reason for this is, the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every gallon is actually the exact amount.

    Another reminder, if there is a gasoline truck pumping into the storagetanks when you stop to buy gas, DO NOT fill up--most likely the gasoline is being stirred up as the gas is being delivered, and you might pick up some of the dirt that normally settles on the bottom.

    Hope this will help you get the most value for your money.
  2. CoonX

    CoonX Member

    Oklahoma City O
    That's some good tips, except for a couple of things.

    Gasoline does expand and contract with temperature changes.
    A tank farm does need to keep track of the temperature for expansion. They operate enough volume that it does matter.

    Here's a formula that I found, it factors the expansion due to temperature rise.

    Gallons X positive temperature change X Coefficient of Expansion(Gasoline = 0.00069°/F Diesel = 0.0005°/F)

    Here's an example of a 15 gallon tank filled with 30°F gasoline, with a 50°F ambient air temperature.
    15 X 20° X 0.00069 = 0.207G
    With a 20° rise in temperature, the gas is only expanding by just over a fifth of a gallon.

    :smile2: I just about missed the ground temperature.
    Since the vast majority of gas station fuel tanks is underground, the fuel temperature is stable and takes a lot longer than a few hours(weeks) to warm up or cool down.

    As for gas going up in vapors because it's being pumped too fast.
    As long as the gas is above it's flash point(-40°F), it's going to put off vapors. Even when being pumped slow, the fuel is being sloshed, splashed and splattered that there's going to be a bunch of vapors.

    About filling up when you have a ½ tank. It is cheaper to add 6-8 gallons versus the 16-18 gallons when you're empty.

    As for filling up when a tanker is delivering fuel, there is between 2-4 filters on the system.


    Also looked at teh Kinder Morgan site, the San Jose Terminal has 32 tanks for a total of 996,800 barrels(41,865,600 gallons)

  3. ryang

    ryang Well-Known Member

    Blacklick, Ohio
    While this is good information I cant see that, would there be contamination of the fuel if it was pumped this way?

    This is also maybe a stupid question but the tanks under the ground are not going to experience much if any of a change in temp, after a certain depth (and no I dont know what that depth is) there is no significant change in temp right?