E85 vs Gasoline - credible numbers?

How many hours in a year?
LOL "Joe Fischer" wrote in message

On Sat, 09 Sep 2006 02:22:19 GMT, wrote:
"Sponsored by OILY INC. [snip
You don't even have a clue what he's talking about, do you? Megawatts per year is a meaningless unit. Moron troll. Eric Lucas
He finally did add "hours" but that might have been wrong, it might have been better to drop the "day" or "year" and not add the "hour'.
Joe Fischer

On Sun, 10 Sep 2006 21:50:26 -0400, "Solar Flare" wrote:

Why would we subtract Hours from the megawatts?
......... Raw solar power MEGAWATT-hours per acre per day. 8,863 MEGAWATT-Hours per year per acre.

Because megawatt hours per acre per year is a gross estimate, and varies from place to place and from year to year.
Megawatts per acre is a much more definitive statement, while the sun shines.
But it isn't all that many megawatts, is it?
43,000 times about 100 = 4.3 megawatts thermal?
At 10 percent efficiency, 430 KW electric?
Joe Fischer

How many hours did you subtract from the Megawatts and what quantity did it yield?
"Joe Fischer" wrote in message

On Sun, 10 Sep 2006 21:50:26 -0400, "Solar Flare" solerfart@hotomali.invalidated> wrote:
Why would we subtract Hours from the megawatts?
......... Raw solar power MEGAWATT-hours per acre per day. 8,863 MEGAWATT-Hours per year per acre.
Because megawatt hours per acre per year is a gross estimate, and varies from place to place and from year to year.
Megawatts per acre is a much more definitive statement, while the sun shines.
But it isn't all that many megawatts, is it?
43,000 times about 100 = 4.3 megawatts thermal?
At 10 percent efficiency, 430 KW electric?
Joe Fischer

In article , Steve wrote:

Lloyd Parker wrote:
Just the heat generated by turning the knob can set it off and cause a fire/explosion.

But not O2 at 1 atm. Otherwise nobody could breathe it without combustion.
Nobody DOES breathe PURE 02 at 1 atmosphere. Even wearing an O2 mask, there is dilution with nitrogen (primarily) and all the other gasses that make up the soup we call "air."
I agree that technically you are correct- there is an activation energy required to start combustion when pure o2 and a fuel are mixed, but the PRACTICAL result is that its much easier to light a mixture of 02 and fuel than air and fuel. Whoever said that you don't need ANY activator was certainly wrong, but the activator can be much more trivial.

Ever use an oxy-acetylene torch? Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.

In article , Joe Fischer wrote:

On Mon, lparker@emory.edu (Lloyd Parker) wrote:
........... Ever use an oxy-acetylene torch?
Yes, 65 years ago, and the gauges say definitely to use NO oil, even at the 10 or 20 PSI at the gauge, a fire could start spontaneously.

Yes, because with the O2 at high pressure, it is much more reactive. When it comes out of the burner, it is at atmospheric pressure.

Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.
For your information, oily rags can start burning without a spark, and coal piled only 10 feet high can start burning spontaneously.

From the DOE:
The coal's temperature begins to climb above ambient. At about 150-300 degrees F, it begins to give off minute, but measurable, quantities of gas--aerosols, hydrogen, and CO(2)--precursors of combustion. As the temperature increases further--at about 600-700 degrees F--relatively, large, visible particulates are emitted. Soon, as the heating rate increases in intensity to about 750-800 degrees F, incipient combustion, and ultimately self-ignition and flame, will occur.
So gotta get to pretty high temp.

Combustion is a normal process in decay

What does this mean?

and in the presence of any organic material, and regardless if it takes at least a static spark, hydrocarbons are less safe if exposed to pure oxygen, and not even safe in air under certain conditions.

So cut down all the trees?

Better safe than sorry.
Joe Fischer

In article , jim wrote:

lucasea@sbcglobal.net wrote:
"Lloyd Parker" wrote in message
Ever use an oxy-acetylene torch? Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.
Actually, since you insist on saying irrelevant pedantic things, I thought I'd chime in one of my own.... Oxygen and acetylene _will_ spontaneously ignite without an ignition source, under the right conditions.
So will diesel fuel. Happens all the time:)
-jim

At 1 atm?

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"Lloyd Parker" wrote in message

Ever use an oxy-acetylene torch? Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.

Actually, since you insist on saying irrelevant pedantic things, I thought I'd chime in one of my own.... Oxygen and acetylene _will_ spontaneously ignite without an ignition source, under the right conditions. Do you know what that condition is and why? It's another p-chem concept that you might have forgotten. Hydrogen will do it too.
Eric Lucas

On Mon, lparker@emory.edu (Lloyd Parker) wrote:

........... Ever use an oxy-acetylene torch?

Yes, 65 years ago, and the gauges say definitely to use NO oil, even at the 10 or 20 PSI at the gauge, a fire could start spontaneously.

Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.

For your information, oily rags can start burning without a spark, and coal piled only 10 feet high can start burning spontaneously.
Combustion is a normal process in decay and in the presence of any organic material, and regardless if it takes at least a static spark, hydrocarbons are less safe if exposed to pure oxygen, and not even safe in air under certain conditions.
Better safe than sorry.
Joe Fischer

lucasea@sbcglobal.net wrote:

"Lloyd Parker" wrote in message
Ever use an oxy-acetylene torch? Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.
Actually, since you insist on saying irrelevant pedantic things, I thought I'd chime in one of my own.... Oxygen and acetylene _will_ spontaneously ignite without an ignition source, under the right conditions.

So will diesel fuel. Happens all the time:)
-jim
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lucasea@sbcglobal.net wrote:

"ghostwriter" wrote in message
Can ethanol be polymerized up to something approximately like octane?
Yes, but increasing the energy density means a loss in absolute energy output. Thats a waste in the case of ethanol
Yes, as an example, ethanol can be dehydrated to ethylene, which can be oligomerized to octene (which can be further hydrogenated to octane if necessary).
This increases energy density modestly (about 30 % by the deltaH(combustion) numbers). I'm not sure what you mean "a loss in absolute energy output", but the process I just described does consume considerable energy. Perhaps you meant "a loss in total energy when summed across the cycle." However, that is trivially true for any processing step, even for your F-T example, since the syngas must have come from something lower in energy like methanol. In fact, any conversion step involves a loss in total energy, unless there is some mechanism to introduce energy into the system (for example, plant photosynthesis).

1kg of ethanol burns for 409cals, it can be converted to 0.6kg of ethylene and 0.4kg of water. Ethylene burns at 370cals/kg so that gives off 225cals. A little more than 50% eifficient assuming you achieve 100% yeild (which you cant) and dont have to input heat to drive the reacion (which you must). Thats before you add any other steps, I am using the 1982 edition of the CRC handbook, but I doubt much has changed.
F-T-diesel is actually worse from a total energy efficiency standpoint, but works out better since it isnt necessary to ferment and distill anything to produce syngas. A syngas generator doesnt care what the feedstock is, whereas a dehydration system would only run on straight ethanol. Diesel also has much higher energy density than ethanol.
Ethanol is useful because it is well understood and easy to produce on a relativly low capital budget. F-T is only efficient as a large scale process currently, since cleaning the syngas so that it doesnt poision the catayst is a difficult and intensive process.
In the end it comes down to priorities and available resourses not to any paticular advantage to either system.

Gordon wrote:

On 8 Sep 2006 07:01:20 -0700, "ghostwriter" ghostwriter25@postmaster.co.uk> wrote:
Gordon wrote: [snip] Can ethanol be polymerized up to something approximately like octane? Gordon
Yes, but increasing the energy density means a loss in absolute energy output. Thats a waste in the case of ethanol but very useful for something like the Fischer-Tropsch reaction where you are taking something like syngas with very low energy density and transforming it into diesel.
Ghostwriter
I was leading into the school of thought that perhaps in the future it might be possible to use a polymerization process (Fisher Tropish or something similar) to produce fuels like JP-8 and diesel, by means of energy inputs from, say, nuclear power plants. This might provide means for using nuclear power, indirectly, as aircraft fuel.
If the organic sludge from the deep ocean floor could be retrieved and processed for ethanol, this would provide a nearly endless source of fuel with very little chance of any environmental harm.
Gordon

The problem would be the water content in the sludge, the water would have to be removed before you could process it into anything. Their might be a process that ignores the water but something like FT or thermal depolymerization which are the first processes to come to my mind would not handle the water well.
Thinking further, with wet material syngas generation is about 50% efficient which sucks but if the feedstock is near free that wouldnt be a huge problem. Pumping the sludge however might be expensive given the density difference between it and the water. If the end result was only 20-30% efficient it might not be worth the destruction of a carbon trap. I will think about the numbers and see if I can come up with anything else.
Ghostwriter

On Mon, jim wrote:

...... Actually, since you insist on saying irrelevant pedantic things, I thought I'd chime in one of my own.... Oxygen and acetylene _will_ spontaneously ignite without an ignition source, under the right conditions.
So will diesel fuel. Happens all the time:) -jim

Are you sure, in 1957 a White truck trouble shooter asked to park the big West Coast rig he was delivering in my Dad's gas station in winter when there was an overheat heater running.
He said not to worry, but I was surprised the building was still there the next morning, diesel fuel was all over the floor because the tanks were filled cold, and expanded.
Joe Fischer

"ghostwriter" wrote in message

lucasea@sbcglobal.net wrote: "ghostwriter" wrote in message
Can ethanol be polymerized up to something approximately like octane?
Yes, but increasing the energy density means a loss in absolute energy output. Thats a waste in the case of ethanol
Yes, as an example, ethanol can be dehydrated to ethylene, which can be oligomerized to octene (which can be further hydrogenated to octane if necessary).
This increases energy density modestly (about 30 % by the deltaH(combustion) numbers). I'm not sure what you mean "a loss in absolute energy output", but the process I just described does consume considerable energy. Perhaps you meant "a loss in total energy when summed across the cycle." However, that is trivially true for any processing step, even for your F-T example, since the syngas must have come from something lower in energy like methanol. In fact, any conversion step involves a loss in total energy, unless there is some mechanism to introduce energy into the system (for example, plant photosynthesis).
1kg of ethanol burns for 409cals, it can be converted to 0.6kg of ethylene and 0.4kg of water. Ethylene burns at 370cals/kg so that gives off 225cals. A little more than 50% eifficient assuming you achieve 100% yeild (which you cant) and dont have to input heat to drive the reacion (which you must). Thats before you add any other steps, I am using the 1982 edition of the CRC handbook, but I doubt much has changed.
F-T-diesel is actually worse from a total energy efficiency standpoint, but works out better since it isnt necessary to ferment and distill anything to produce syngas. A syngas generator doesnt care what the feedstock is, whereas a dehydration system would only run on straight ethanol. Diesel also has much higher energy density than ethanol.
Ethanol is useful because it is well understood and easy to produce on a relativly low capital budget. F-T is only efficient as a large scale process currently, since cleaning the syngas so that it doesnt poision the catayst is a difficult and intensive process.
In the end it comes down to priorities and available resourses not to any paticular advantage to either system.
I have read about microbes that can convert syngas to ethanol as well

as catalysts that can convert syngas to ethanol under the right conditions. I wondered why you would not just make SNG or methanol and then I figured that SNG and methanol might sell for a $1 per unit and ethanol might sell for twice that.

jim wrote:

lucasea@sbcglobal.net wrote:
"Lloyd Parker" wrote in message
Ever use an oxy-acetylene torch? Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.
Actually, since you insist on saying irrelevant pedantic things, I thought I'd chime in one of my own.... Oxygen and acetylene _will_ spontaneously ignite without an ignition source, under the right conditions.
So will diesel fuel. Happens all the time:)
-jim

If we're going to all be pedantic, then you're wrong Jim. There IS an ignition source, its the heat generated by compression of the intake air. :-p

Lloyd Parker wrote:

In article , Steve wrote:
Lloyd Parker wrote:
Just the heat generated by turning the knob can set it off and cause a fire/explosion.

But not O2 at 1 atm. Otherwise nobody could breathe it without combustion.
Nobody DOES breathe PURE 02 at 1 atmosphere. Even wearing an O2 mask, there is dilution with nitrogen (primarily) and all the other gasses that make up the soup we call "air."
I agree that technically you are correct- there is an activation energy required to start combustion when pure o2 and a fuel are mixed, but the PRACTICAL result is that its much easier to light a mixture of 02 and fuel than air and fuel. Whoever said that you don't need ANY activator was certainly wrong, but the activator can be much more trivial.
Ever use an oxy-acetylene torch? Or an atomic esmission spectrometer? Oxygen and acetylene. Do they ignite spontaneously at the tip of the burner? No. Requires a spark or a flame.

This is the point that comes in any discussion in which I have been agreeing with Lloyd where I stop and say "DUH! I was agreeing with you, you nincompoop." And regret ever posting that I agreed in the first place.