I have a little knowledge of the benefits of ethanol in automotive engines, but a newb with aviation engines. So please inform me on the differences with aviation engines.
I have learned that not only flex fuel vehicles, but the supermajority of the existing fleet of America's vehicles achieve optimal mpg in the range of E15 to E40 fuel without any tweaks to the engine or emu. Since higher proportions of ethanol involve blending E85 and regular 87 aki gas, the cost per gallon is significantly lower than regular 87 aki gas in California. It is not intuitive, since ethanol has lower energy than gasoline. But there are many journal articles about this and here is a summary: https://www.eesi.org/papers/view/fact-sheet-high-octane-fuels-challenges-opportunities Most who disparage ethanol claim that the fuel lines and seals are destroyed by it. That has not been the case in cars/trucks for decades. The valid concern is for improper aluminum alloys and/or coatings. Late model cars don't have an issue here either. Your old lawnmower may, however. Base "sub-octane" gasoline used for regular grade is 84 aki. The 10% ethanol brings the octane up to 87-88. Higher percentages of ethanol like E30 will bring you over 94 aki. Wouldn't it be great to achieve a high octane fuel for higher compression ratio (or turbocharged) engines by blending E85 with regular grade E10 at a price below regular gasoline? Today, in my neck of the woods, the price for Sam's Club regular gas is $5.69. E85 at my local 76 station is $4.09. (The oil companies raised the gasoline price over a dollar in the last 2 weeks here. Some cock and bull story about unplanned refinery maintenance.) The other issue is water. It is well-known that the US Army Air Forces achieved great benefit from water injection in their aircraft during WWII. Most understand the huge benefit of water added to fuel in increasing power-stroke pressure while decreasing cylinder temperature. Unfortunately, water and gasoline are not miscible so the water needs a separate system. That is a huge defect of gasoline. However, water and ethanol are miscible. So what happens when you blend gasoline, ethanol and distilled water? At what temperature and blend percentages do they separate? Here is a recent study: https://www.researchgate.net/publication/233269816_Low-Temperature_Miscibility_of_Ethanol-Gasoline-Water_Blends_in_Flex_Fuel_Applications So, as you can see, ethanol-gasoline blends with a little water doesn't seem to be a big deal in the automotive world. I drive up to Tahoe and other locations in the Sierras above 8,000 feet on hot summer days and cold winter days without issues. I don't know of anyone that has issues. So what is the issue in aviation engines? On Fri, Sep 30, 2022 at 12:58 PM Mark Wegmet <markweg...@charter.net> wrote: > Larry; > > Let's look at the "chemical" end of this question. > > 1) Water and alcohol are fully miscible: what this means is that these > molecules have such a strong affinity for each other that they "bind" > together with a strong enough bond that they will not naturally separate > (i.e., don't think that you can take a water/alcohol blend and put it in a > container and "hope" that it will separate on its own [within the > constraints of saturation of one molecule or the other]). 2) having said > that, don't even think that your "gascolator" is going to separate this > from the fuel stream. 3) In theory, if you have a fuel with gas/ethanol and > add water to it, then run it through a strainer specifically designed to > separate water from fuel, you will remove the ethanol as well... > > Having said that, it seems like a hell of a lot of work to get something > (ethanol free gas) that you can find at many gas stations. I live in one of > those counties in Wisconsin that is under EPA scrutiny, so can't buy it > locally, but four miles away is a county not under the same EPA oversight > that has 89 and 91 octane ethanol free (and lead free) gas. I run it in my > yard equipment. > > To give you a technical answer to your question (10% ethanol in 5 gallons > of gasoline) you first need to determine is the blend V-V (Volume for > Volume) or W-W (Weight for Weight). Gasoline is 6.3#/gal.: Ethanol is 6.58 > #/gal.... so for a barn yard chemist, they are "close enough for KR work". > > A 90/10 blend would be a half gallon of ethanol per five gallons of fuel. > Water is 8.35 #/gal..... > > According to some publications, the proportion of water to ethanol > (alcohol) is not important, so, again, theoretically, if you dump a half > gallon of water into your ethanol/gasoline 10% blend, you should be able to > separate the ethanol by filtering out the water with the appropriate filter > media... again, why bother? As another respondent noted, you would also > need to deal with the change in anti-knock properties of the fuel. > > Even at six bucks a gallon, the time you spend with all of the B/S and > other stuff (even if you are retired, like me, and your time is "free") > would buy you some awesome Southern Illinois Biscuits and Gravy at your > favorite airport restaurant if you just spent the $120 to fill up the plane > and go fly. > > JMHO > Mark W > N952MW (res). > > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>... > On 9/30/2022 1:37 PM, Flesner via KRnet wrote: > > > I found the following on the internet: > > *"Water is absorbed into ethanol* because water molecules are small > enough to fit between the larger ethanol molecules." > > Question: If I have a fuel strainer that blocks water but will pass > gasoline can I add water to gasoline containing alcohol and then pass the > fuel mixture through the strainer to remove the water / alcohol mix? Will > the alcohol separate from water and pass through the strainer? IF this > process removes the alcohol from the gasoline what is the amount of water > needed to remove 10% alcohol from 5 gallon of gasoline? > > There has to be a catch here or everyone would do it. I have a dozen or > more 5 gallon fuel containers that I used at one time to get free 100LL > from the waste barrel and filter for use in the KR. That option is no > longer available and $6 a gallon 100LL is not a great incentive to go > flying. > > Inquiring minds want to know????????????? > > Larry Flesner > > > > -- > KRnet mailing list > KRnet@list.krnet.org > https://list.krnet.org/mailman/listinfo/krnet >
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