Gasoline storage

[BioHazard]

I plan on buying about a 600 gallon tank that I can have filled with premium non ethanol gasoline, which is not for sale anywhere close by. I figure it might last me about 6 months but I want to design it so the fuel can last as long as possible if need be. A bottle of Stabil says it will keep gas good for about a year. Never really tested it for myself.

Is there more I can do than that to keep it fresh? What, exactly, causes gas to go bad? Is it contact with oxygen? I was thinking about hooking up a bottle of CO2 or some other inert gas to keep the inside of the tank purged of air. Would that help anything? Obviously it needs to be kept dry, but at least water can be seperated out of "real" gasoline.

[rcavictim]

If you could keep it refrigerated, say just below water freezing temp it ought to be good for a long time.  Just a guess.  That shud keep any water born algae from thriving.  Keeping the airspace free of O2 might also help as you suggested.

[DanG]

This is a hassle that small aircraft owners have - and where it really pays off for them is when there is a group purchase so the delivery pumps 2000 or somesuch large number of gallons.

Before you fix on a tank size find out the ordinances on storing gasoline - if the tank is on indoors, on casters and mobile one set of rules apply, if its stationary and over a certain gallon amount you probably will have to build a containment berm around it, maybe a weather - sun cover and have it XX distance from occupied structures, etc..

Inquiring at your local regional airport about which vendor services that area and what the fire regs and the vendors rules are would be a good start. But being able to choose the recreational non-ethanol (as its called here) may not mean you're avoiding seasonal mixes, what works at -20°F here give fits to a third of my engines trying to run it at 70°F so having a large tank may be a disadvantage there.

The last time gas popped from $2 to $4 a gallon, and before plastics got expensive I nabbed six five-gallon jugs for $6 each, filled them with high-test and had the savings pay for the jugs with the first filling. I found an aluminum hutch for $50 that holds eight five-gallon jugs and have that in the perpetual shade area of my garage, for five months out of the year temperatures are near or below freezing, and its out of sight and somewhat safer than just sitting around.

[mike90045]

refrigerated would invite condensation, so a purge gas would be needed.  Look into a dewar of liquid Co2.  The bleed gas from that should last you a month

[tinkerer]

We use stabil in our gas tractors, mowers, pumps, chainsaws, ect and it seems to work well. I have an old pickup that has gas with stabil in it and the gas is going on three years old and it still smells good, not stale, and still starts and runs well on it. I try to start the pickup once a month or atleast once every other month or so and let it warm up good. I'm more worried about condensation and rust than gumming up.
Just my 2 cents..
Ben

[cognos]

Contact with oxygen is what causes gasoline to go "bad" or "stale" more quickly. But modern gasoline degrades on it's own. Gasoline has a shelf life of around 6 weeks. That means that it will still "make spec" after 6 weeks of storage. That doesn't mean that it's "bad" in week 7 - it just means that it will no longer pass "fresh gas" specifications. Older gasoline may still run quite well in many engines. But at some point, old fuel may cease to have the desired starting characteristics, the right octane rating, and it may have some foulants present - polymer breakdown component, gums, etc.

"Breakdown" can be minimised but not stopped.

Nitrogen is the choice for a gas blanket, as CO2 contains oxygen. For optimum storage, you'll need to pressurize to about 3 PSI - one PSI over the gasoline's natural tendency to evolve butane on it's own, which will try to fill the vapour space up until about 2 PSI, and form it's own oxygen-excluding gas blanket... so why bother.

Cool storage is better. But cold gasoline pumped into a tank will indeed attract water. So ambient maximum temperature storage below 100°F is the actual spec. 85°F is an ideal maximum. Below doesn't make much difference - 6 weeks again...

No matter what you do, the gasoline will begin to degrade chemically. Modern reformulated gasoline contains unstable chemical components, and there is nothing you can do about this. No consumer-grade gasoline stabiliser can stop gasoline from "breaking down", losing some volatility, dropping an octane number or 2, forming some gums, varnishes, polymers, etc... in storage longer than 6 weeks. Period.

Gasoline stabilisers primarily contain what you say you don't want any of - alcohols! Usually ethanol, methanol, or isopropyl. Alcohols scavenge any free water, or water vapour in the vapour space. The vast majority of the rest of the gasoline stabiliser is a dispersant - to keep the alcohol/water mixture - now called an azeotropic mixture - in suspension. And some dye, to make you believe you're buying something exotic... Yes, there may be some other interesting chemicals listed on the ingredients - they do nothing, for the most part, or they may be part of an additive package that has nothing to do with stabilising your gasoline for storage - things like a corrosion inhibitor, a detergent, some solvents, etc... if you get lucky, there may be some BHT. Butylated Hydroxy-Toluene. This is an actual Oxygen Scavenger - one of the only oxygen scavengers available over-the counter. But it is rarely in there in anything but a trace amount, far below the threshold where it will do any good whatsoever - we call this an "ingredient hook" for consumers with just enough interest to look it up and find out what it is, and pronounce it to be good... without really having enough information as to whether it will actually be doing anything for you...

There are real, hard-core. gasoline stabilisers out there. But consumers can't buy them. They are special purpose (think military), and they are too hazardous to sell to the general public. Don't believe the hype...

Bottom line is, long-term storage of modern gasoline is to be avoided, if possible. Not much you can do will stop it from degrading.

Long-term storage of heavier fuels is easier to accomplish...

[Tom Reed]

I have had outstanding results with Pri-G. Stored gas upto 3 years with no detectable degradation. It's the only product that claims to restore stale fuel!

[cognos]

I'm sure Pri-G is a wonderful product, and I'm sure it works well for many people. I just have to wonder why a reasonably good fuel stabiliser/conditioner-type product would resort to language in it's advertising to the effect that it can restore old fuel to "refinery-fresh" specifications... because it can't, nothing can, and it's not language that needs to be used - for me, that kind of marketing kind of negates all the rest of what they have to say about it, which is quite reasonable, even for me, when I read between the lines...

It's an additive package that contains an oxygen scavenger, a dispersant, and a detergent, possibly some corrosion inhibitors, nothing wrong with any of these. But without an alcohol, it can't raise the octane number back to spec, and they actually state this in their ad copy. So - how can it bring any fuel back to "refinery-fresh" spec?

There is no consumer-available product that raises octane number that isn't an alcohol. At least in North America. You can't buy tetra-ethyl lead, MMT, MTBE, etc. to add to your gasoline to raise the octane - these products are all at least extremely hazardous,  and quite possibly deadly if used improperly.

You really want to improve the quality/storability of gasoline? Get your hands on some 110/130 Avgas. Mix it 25/75 with any other RUG - containing alcohol or not. The lead will increase the octane # of the entire batch, the additive package is more robust, and it will store longer. But again, I recommend not storing for longer than you absolutely have to.

I have to question the complaints against alcohol-containing fuels in engines. The research, and my real-world experience, just doesn't support the complaints against very poor mileage, or poor performance - in modern road applications, and in properly tuned and maintained off-road engines. Although I don't have a diesel engine (!), I have many old, antique, engines - some outboards - from 3 HP twins to 75 Hp Mercs -  that get used all the time with no problems at all... some need 16:1 premix with just regular 30wt oil... I use fresh pump gas for all of them, all containing up to 10% ethanol here in Ontario. I have more than the usual complement of 2 stroke yard machines, and they get used - I have 8 acres of woods and gardens here... never a problem on pump gas. My oldest leaf blower is 25 this year. A tweak of the carb to adjust for cold or warm weather, it still runs fine. My antique bikes all run perfectly on old pump gas, although I have one that requires premium due to having an 11.5:1 compression ratio.

You know what I spend my money on to keep my stuff running well? Oil and spark plugs. I inspect the plugs regularly, clean and re-gap often, and replace once a year. I buy conventional oil, change it regularly - more often than recommended. I mix 2 stroke with a bit more oil in the gas than specced. I never pay any attention to the gas - it is all the same spec, often from the same refinery, it just has a different brand name on it. I buy the cheapest fuel from the busiest station - that way, I can be reasonably sure it's fresh.

I no longer own anything that actually requires synthetic oil. If ya got lotsa cash, go ahead and use it - it's the best oil in the history of oil. But conventional oil is more than adequate for the vast majority of engines. Sorta like "premium" gasoline - not required by up to 90% of the people who buy it...  - but hey, somebody's gotta pay for my pension...

[LowGear]

I sure hope your research has proven that this program is worthy of the expense and the extreme / extraordinary danger? 

If you're within a block or two of me and I find out we'll soon learn I'm not a Libertarian.

While I'm not the biggest fan of insurance companies in the room they would (I think understandably) get very busy reading, reading and rereading their policy with you should it come to their attention.

Hey!  There's always one in the crowd.

Casey

[Tom Reed]

Well I don't have any technical degrees, just 27 years driving the same '74 Scout on all kinds of pump gas. It is tuned so that I need premium when towing to keep it from pinging below 2k elevation. So it will ping a bit on regular under load. When running old gas treated with Pri-G it does not ping at all. Can't say what the actual octane is though. The Scout seems to live the alcohol fuels to, but it really ran bad with the MTBE gas when they were using that. I add the Pri-G to all the fuel that goes into the chain saws, weed whackers, mowers, motorcycles, generators and tractors. No fuel related carb issues with these engines, even when I've neglected to drain the carbs before storage.

[cognos]

IF the noises you are hearing from your well-loved '74 Scout are in fact related to a higher-octane requirement under load, and if they go away when using Pri-G, then I am at a loss as to what is going on, since their own literature acknowledges that their product does not increase octane. But hey, if everything were knowable, life would be boring, yes?

Everything else you - and they - say about what it does makes sense to me. It's a detergent/dispersant/possible oxygen scavenging gasoline additive package. This will certainly keep carbs clean, and possibly keep crap from depositing throughpout the fuel system for a longer period of time than if you didn't use it. But as to keeping the gasoline "fresher", or extending it's usable life as an on-spec motor fuel - I'm still dubious.

Let make a comparison.

Let's say they changed the advertising for aspirin. Let's say they now tell you it's good for pain, headaches, prevention of heart attacks, and, if you use it, you'll be more popular with women. Or men. It's up to you.

Just seems to me that the last bit is spurious, and calls into question all the claims in the entire ad package, for no reason. Can't prove or disprove it, but it just doesn't sound quite right...

Same with Pri-G. Does all those wonderful things as stated, no real question about that, then they tell me it brings old fuel back up to "refinery-fresh" spec. Well, no, it doesn't, and if they hadn't claimed that, I'd have more respect for the product.

Just my opinion.

[Tom Reed]

Yes it could be due to the fact that I'm endowed with the "special" blend California gas that things have gone so well.  Your point is well taken. Now I'm going to have to fill 2 clean drums and leave them side by side for 5 years and see what happens. 

[BioHazard]

It's not so much problems with ethanol I have, the problem is the cost and the bad fuel economy it causes. Simply put I want more BTUs in my gas. Most of my vehicles require premium. I have a Jeep that's been sitting for about a year with a full tank of gas(e10) and right now it reeks. In the past I've taken the same jeep through an emissions test on 3 year old non ethanol gas, and passed just fine. I don't think it will run on the gas that's in it now. Having it delivered in bulk will also make it easier for me to apply for the tax refund for fuel used off road.

I sure hope your research has proven that this program is worthy of the expense and the extreme / extraordinary danger? 

If you're within a block or two of me and I find out we'll soon learn I'm not a Libertarian.

While I'm not the biggest fan of insurance companies in the room they would (I think understandably) get very busy reading, reading and rereading their policy with you should it come to their attention.

Hey!  There's always one in the crowd.

Casey

I'm looking at a double walled, three compartment tank. I have an industrial shop with a hazmat containment area. Technically the zoning would allow me to open a gas station. I don't see that as being any more dangerous than a big propane tank so many keep parked right next to their house...or for that matter parking in an attached garage with 20 gallons of gas in your tank....

[LowGear]

Ah ha!  You know what you're doing.

I've had great success with Chevron premium but I just paid $4.80 a gallon for it.  Even better than the no ethanol stuff they sell at the harbor.

I was talking with my Bio Diesel guru and turns out he had a 55 gallon drum of methanol in his garage.  When it got down to 25 gallons he relocated it to a shed out back.  Still dangerous but far better than one door from the kitchen.

Casey

[BioHazard]

Ah ha!  You know what you're doing.

...or at least I can pretend well.  

Actually my shop is right next to the local airport, but they refuse to sell me gas unless I show up with an air plane...

Some of the gas I will probably sell to friends with boats to keep my stock fresh, I am very close to a popular river launch but there is no "marine" fuel available. Hell, maybe I should open a gas station...