Ethanol as a fuel (1 Viewer)

[Marina89]

I was just wondering, other than that it is renewable and undergoes complete combustion, what is another advantage of using ethanol as a fuel? I was going to use 'carbon neutral' but I've just been told that it's incorrect.

Any help would be much appreciated =) Thanks

 

[Aerath]

Carbon dioxide neutral is correct (I think). It's cause the amount of moles of CO2 liberated from combustion and fermentation is reabsorbed when plants perform photosynthesis.

 

[Marina89]

Yeah theoretically it's right but it actually doesn't take into account the carbon dioxide that is used in photosynthesis to produce the glucose

6CO2 + 6H2O -> C6H12O6 + 6O2

so there is actually more carbon dioxide used than is produced

 

[Marina89]

Ok wait I do get what you're saying.. so it's sorta assumed that all of the CO2 released during fermentation and combustion of ethanol is going to be absorbed during photosynthesis

 

[clintmyster]

I've been marked wrong in exams for saying carbon neutral because you need to consider the energy requirements in transportation as well as combustion.

Another advantage would be that the fuel combusts more cleanly and evenly due to the oxygen atom. Octane has toxic additives like MTBE added that is harmful for the environment. For more info, check chem contexts on it. I suppose also it would create more areas of employment, particularly for people struggling the economic crisis but that might be pushing it xD

Other than that 3 adv and 3-5 of the following disadvantages would be enough.
Talk about the infastructure issues, less energy produced per gram or mole of ethanol as opposed to octane, issues with agricultural land needing to be sacrificed, herbicides + insecticides sprayed which degrade soil quality and can run off into lakes and streams harming marine life.

 

[annabackwards]

It does have the potential to be greenhouse neutral, but correctly fossil fuels would still need to be used in the distillation of ethanol and harvesting/planting of glucose rich plants so it actually isn't greehhouse neutral.

Another advantage would that is burns cleaner than traditional fuels such as petroleum and countries could rely on internal agricultural output to produce fuel instead of oil exports.

EDIT: already mentioned by clintmyster.

 

[Marina89]

Thanks guys, that helps a lot!!

 

[carlytse621]

- Job creation in new fermentation plants and other processes
- Regional economic growth in rural areas
- Biodegradable

 

[mrhorseham]

just say it has potential of reducing greenhouse gas emissions if solar/wind energy is used in its production.

 

[jp92]

ethanol as a fuel would result in decrease in the reliance on crude oil for fuel which allows the minimal crude oil remains to be used for the petrochemical industry.

 

[MrMMMan]

Ethanol is also more reliable in that it can be produced from petroleum cracking as well as fermentation.

 

[MMEB]

Ethanol has a lower boiling point than petrol. What does that mean in terms of an advantage/disadvantage of its use as an alternative fuel??

 

[harry4]

i suppose less energy would be used in combustion

 

[brenton1987]

A couple more points for you all

Octane is immiscible in water and less dense so in the event of a spill it will form a distinct layer on top of water allowing for easy clean up. Where as ethanol is miscible in water so the result will be a toxic alcohol solution which cannot be cleaned. Disadvantage of ethanol.

Octane vaporises more easily than ethanol. In confinement octane vapour will collect creating an explosive hazard. Ethanol will stay as a liquid. Advantage for ethanol.

Octane has a much larger enthalpy of combustion so more energy will be obtained per unit volume from octance rather than ethanol. Disadvantage of ethanol.

 

[chuboy]

Some engines (and car owners) disagree with ethanol fuel making it hard to mandate - issues with warranties, engine repairs, etc.

Increased fuel consumption when using ethanol.

Stock for ethanol may eventually compete with food supplies, particularly in third world countries where returns from SUV-driving soccer moms outweigh those from starving African villagers.

Consider agricultural consequences of raping the land for ethanol stock.

 

[Lukybear]

Various advantages with Ethanol:
-Renewable resource
-More CLEANER COMBUSTION: not complete combustion, equating to less amount of soot + co emited, both of which are poisonous. Other emissions are also reduced, i.e. buckyball, benzene etc...
-Economically benefical, as there is a less need for importation and reducing balance of payment problems.
-Can be injected directly into fuel tank and used with petrol
-Easier to be ignited then petrol

 

[study-freak]

It does have the potential to be greenhouse neutral, but correctly fossil fuels would still need to be used in the distillation of ethanol and harvesting/planting of glucose rich plants so it actually isn't greehhouse neutral.

Another advantage would that is burns cleaner than traditional fuels such as petroleum and countries could rely on internal agricultural output to produce fuel instead of oil exports.

EDIT: already mentioned by clintmyster.

best way of putting it, IMO

 

[Viru10]

If you were asked for the chemical or physical properties that make ethanol a suitable fuel to replace petroleum, could you say that it is less of a hazard in its storage and management because it is less volatile compared to a fuel like octane which could vaporise, collect and be explosive?

 

[Aerath]

Yes you could say that.

 

[Viru10]

I think im getting a little bit mixed up with ethanol's advantages and disadvantages as a replacement for fuels that are obtained from petroleum...

How can you use ethanol's voltatility and ignition temperature to relate to adv. and dis adv.'s?

What ive got atm is:

Lower ignition temp compared to common fuels such as octane, hence less energy required to ignite (advantage)

and heres wher i get mixed up, is ethanol MORE or LESS volatile then octane? and how does it relate to an advantage or disadvantage as a fuel?