" 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
fast
mode. 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 isactually the exact amount.
Another reminder. If there is a gasoline truck pumping into the storage
tanks 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."
Underground tanks have VERY little in the way of daily temperature swings. In any case, gas dispensers are temperature-compensated. Periodic Weights and Measures checks ensure the accuracy of dispensers.
Vapor production is dependent upon temperature and vapor pressure. Pumping rate has negligible effect on how much vapor is produced.
The amount of vapor even a fully empty tank can hold under normal conditions of temperature and vapor pressure would reduce to a few cc’s at most.
Gas dispensers have fuel filters to keep tank sediment from getting into your car.
I can verify the bit about not buying gas while they are off-loading the gas truck. I ruined a carburetor when I ignored that advice and ended up with a ton of crud in the fuel system. That might have been the gas station’s fault for letting crud accumulate in their fuel tanks. How often do they clean the junk out of their fuel tanks?
I agree they are supposed to have such filters. They are even supposed to have baking soda filters that shut off the pump if there is water, instead of gasoline, in the system. Nevertheless, earlier this year I pumped 8 gallons of water mixed with sludge into my tank at $2.879 per gallon. I now mistrust gas station filters.
So if this was all true, I would be lucky to save a few $$ in my lifetime.
Worse thing that has happened to me when buying fuel and now I will only buy fuel from places are go threw alot of fuel so the tanks are beings refilled frequently. Because I got fuel in my tank that had gone off. I got horrible mileage an my care ran a bit rougher.
I’m waiting for someone to explain the workings of an internal floating “roof” in an underground tank. Every (underground) tank I’ve seen is in the shape of a cylinder lying on its side. How exactly does this magic roof work?
I call BS.
pullin (who used to drive airport tanker trucks and filled them from underground storage tanks)
If filling an empty tank in “fast-mode” at any time of the day I want is going to cost me an extra 10 cents every time I fill up I seriously could not care less.
Good points all around. The part that got me was that gasoline evaporates “faster than I can imagine.” I may not have the best imagination in the world, but I can use said imagination to envision an entire tank of gas evaporating in less than a second. I’m pretty sure it doesn’t really evaporate that fast.
Also, isn’t the fuel tank pretty air tight? If all the volatile portions of the gas evaporated away, your whole tank might be gone when you park at the mall for a couple hours in the summer!
I would think the mileage cost of always hauling around a half tank of gasoline would offset the evaporation effect. Also, there is an inconvenience factor and gas cost to make additional side trips to the gas station.
Gasoline is volatile, to be sure, but it’s nowhere near THAT volatile. If you fill a small pan to, say, an inch deep with gasoline and let it sit (outdoors!) somewhere warm and sunny, you’ll see it will take quite a while for it to all evaporate away. Most alcohols and acetone, for example, are much more volatile than gas.
