MattiasD skrev:
Nu har jag gjort en separat mätning mha "separeringsmetoden". Jag slog i 1 dl E85 i ett mätglas och fyllde med vatten. Den bensin som separerades uppskattade jag till 11 cl, dvs 11 % bensin vilket ger en etanolhalt på 89%. Bilen säger 85,1 % etanol. Men några frågor har ploppat upp:
Frågan är vad vätskan innehåller som inte separerades? Det är väl inte bara etanol? 89 % etanol + andra ämnen?
Bilen mäter 85,1 %, det kanske är verklig halt etanol? resterande 14,9% är bensin + andra ämnen?
Några kommentarer?
Jag brukar hänvisa till denna instruktion om hur man skall mäta upp innehållet i E85. Av formeln:
The hydrocarbon percent is calculated by:
2.1 + 1.94*(total volume - alcohol/water volume) framgår att en del av bensinen blir kvar i vattnet så man kan inte göra en för enkel räkning.
Citat:
E85 is a form of alternative transportation fuel that
can be produced from a wide range of renewable feedstocks.
As is the case with all forms of fuels, it is critical
that the integrity of the fuel be maintained and that
seasonal volatility adjustments be made. The following
summary describes a “field test” procedure to determine
the levels of hydrocarbon and alcohol in E85.
The following equipment is available from VWR
Scientific, 800-932-5000. Reference numbers are those
used by VWR. Other equipment suppliers are available.
50 mL pipettes
Cat. #52966-217
Safety bulb
Cat. #53497-202
100 mL cylinders,
Cat. #24762-117
Procedure for Determining Hydrocarbon
Percent of Ethanol Fuel Samples
Safety Note: Hydrocarbon- and alcohol-resistant
gloves are recommended when collecting samples and
conducting tests. Additionally, eye protection should be
utilized. Testing personnel should also carry water in
plastic containers.
1. Using the suction bulb, pipette exactly 50 mL of fuel
sample into the graduated cylinder.
2. Add about 48 mL of water to make the total liquid
volume just under 100 mL.
3. Place the stopper in the cylinder and shake vigorously
for about 15 seconds.
4. Carefully loosen the stopper to release any accumulated
pressure; do not remove the stopper.
5. Close the stopper again and place the cylinder upright
on a level surface. Allow the mixture to sit for about
15 minutes.
6. Record the total volume of liquid by reading the lowest
part of the upper meniscus (the curved interface
between the liquid and air).
7. Record the total volume of the alcohol/water layer by
reading the lowest part of the lower meniscus (the
curved interface between the two liquid layers).
Calculation
• The hydrocarbon percent is calculated by:
2.1 + 1.94*(total volume - alcohol/water volume)
• Assuming the sample was an ethanol/hydrocarbon
mixture, the ethanol percent is 100 minus the
hydrocarbon percent.