Alcohol fuel - The obvious answer, Yes or No?

MetaKron said:
And there does need to be careful temperature control when distilling alcohol for fuel or it will end up with too much water to be useful as fuel....
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Can you explain better what you mean by "temperature control"? I suspect that in ignorance, you are confusing it with thru-put control. (The temperature of the distillation pot does not change much as the liquid boils.)

I know a little something about distillation. One of my summer jobs as an undergraduate student was with the Lion Oil company's Lab in Southern Arkansas, (I forget the city now.) At start of start of summer I poured 55gal of benzene and 55 gal of Carbon Tetra Chloride together in the "pot" of a small (~3m tall distillation tower) research distillation unit and spent the summer trying various ways to get them separated again.

This is not as silly as that sounds as my job was to evaluate the number of "theoretical plates" for a particular perforated metal packing that Lion Oil was thinking about buying for their main refinery. (Actually it was quite an important job. I never learned if the did or did not spend millions based on my report.) The packing looked sort of like "rice checks," but the small slightly curved squares were shiny metal with many holes punched in them but no removal of any metal by the punching. - About 3 m of that packing got to 22 plates, with relative low thru put, but of course, the packing was just a continuous jumble in the vertical column.

Again tell what you mean by “temperature control”
 
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Roman said:
Just heard on NPR that with recent, revised number crunching, ethanol is a viable fuel, so long as they get it from stuff that doesn't require enormous nitrogen inputs....
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Glad you are beginning to understand.

The ratio of energy in alcohol produced to total non-solar energy input (for fertilizer, plowing, crop collection, distillation, etc) varies greatly. In Iowa, with corn as the crop, and substantial fertilizer required to compensate for the limited growing season, in my opinion the energy yield ratio is about 1.1; I.e. a 10% net gain, although some experts are still of the opinion there is a slight energy loss. In Brazil, with more sun and manual labor the energy gain ratio is about 8!

Just today, Adriabo Dalbem, Director of Supplements, for Brazil's division of Royal Dutch Shell oil company announced that they will buy and send 30 million liters of alcohol to the US and plan to ship a total of 150 Million liters to US from this fall's harvest of cane. They will only confirm that the price paid to Brazilian producers will be "AT THE MARKET," but that currently means approximately US$0.55/L (or if you like US$2.06/gallon.) I think it will also be burdened with import duties of US$0.51/gallon (if they can get it in before the extra 10cents/gal Iowa corn producers want is added.) for a total of $2.57/gallon. Shipping etc cost will add about 13 cents so let us call it $2.70/gallon. (I am only guessing at the import duty by setting it equal to the alcohol subsidy now paid to US producers. - If anyone knows what it is, please post.)

On an energy equivalent basis this translates to $3.86/gallon of gasoline. - Obviously, Shell either is willing to test the import system, even if it loses a little or they know something about where gasoline prices are headed soon.

There may be other factors in their analysis. For example, the demand for US corn based alcohol may get so great with more cars, especially in California, using E85 that there is a squeeze on the availability of alcohol as additive for regular gas, especially in states where both lead and MBTE is illegal, so shell may be just taking out an insurance policy against tight supply with this first ever substantial shipment to US of Brazilian alcohol.
 
By temperature control, I mean that separation of alcohol and water by distillation is a bit tricky. The vapor pressure of water isn't a lot different from the vapor pressure of alcohol at the boiling point of alcohol, which is about 173 degrees F. The vapors contain a huge proportion of water that has to be separated. Obviously the water will condense out at below its boiling point. It will also absorb alcohol from the vapors as it condenses, so that water needs to go back into the mix. You need a stretch that says between 212 F and 173 F. Too long a stretch and the scheme becomes inefficient because too much alcohol returns. Too short, you deliver too much water to the output.

Maybe it's not rocket science and not high precision, but there are ideal temperatures and lengths for the coils where the water is condensed. Ideally the part where the water condenses is all downhill back to the cauldron so it doesn't start burping. Then the alcohol condenses on the way down the other side and drips into whatever you use to catch it. Where the tubing starts downhill it needs to be less than 212 F and more than 173 F. I am sure there are other details I'm not mentioning in this quick essay, or that I don't know. If you are using electricity or petroleum to heat the mash you definitely want high efficiency when you produce fuel. I wish they would do it with solar heat.

A homesteader using wood as the source of heat might well find that he can produce alcohol at a much lower cost than gasoline since wood used as fuel, if it grows on your own acreage, costs the equivalent of pennies (maybe less than a penny) a gallon in heat. It's essentially free even when you use a chainsaw to cut it. A chainsaw can make a hundred pounds of wood usable as fuel using very little out of a tank of gas, I know from experience. One man with a handsaw can also break down large trees into wood, although that can be a waste of usable man-hours.

Commercial production has certain limitations and imperatives. Home producers can strip the corn cobs, or not, and throw them into the digester. The kernels soften with soaking. Any source of starch works. Cellulose works but that doesn't go as easy.

What makes it expensive is when you have to comply with regulations that force you to add a certain amount of petroleum or more poisonous alcohols to the mix so that it is not drinkable. I haven't looked those up in a while, but it definitely cuts down the savings if you have to mix three dollar a gallon gasoline with it or even more expensive isopropyl alcohol. I'll vote for methyl at 2 percent myself.
 
To MetaTron:

You appear to be familiar with the typical moonshiner's "pot and coil" distillation of alcohol. Industral production does not use temperature controlled tubing or coils. Instead there is a vertical cylinder, usually with some horizontal plates with holes in them (for the vapor and condensate to pass thru) that support the packing. They are well insulated on the outside. No heat is added or removed thru the cylinder walls. Nature (physical chemistry) automatically establishes the "perfect" negative vertical thermal gradient for the thru-put in the column.

Get a book that discusses a distillation tower and understand the concept of a "theoretical plate" before posting more in ignorance.

See/read my post again. I have worked 3 months with a small research lab version of a commercial distillation tower. They have no "tubing." They have no "coil." They are large (more than 1 meter in diameter) vertical cylinders. Have you ever even seen one?
 
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Billy T said:
To MetaTron:

You appear to be familiar with the typical moonshiner's distillation of alcohol. Industral production does not use temperature controlled tubing. Instead there is a vertiacal cylinder, usually with some horizontal plates with hole in them of course that support the packing.

See/read my post again. I have worked 3 months with a small research lab version of a commercial distillation tower. They have no "tubing." They are large (more than 1 meter in diameter) vertical cylinders. Have you ever even seen one?
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They're not going to get the results they want unless they condense the water out without losing the alcohol. That "packing" had better be at the right temperature, so there had better be some kind of temperature control. I don't know what you are quibbling about.
 
MetaKron said:
They're not going to get the results they want unless they condense the water out without losing the alcohol. That "packing" had better be at the right temperature, so there had better be some kind of temperature control. I don't know what you are quibbling about.
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Read again my last post, now that it is complete. (I am dyslexic so it is necesary for me to post and check. When I do so, I often add new parts to make it more clear.)

You replied before I had edit it to tell you that nature supplies the "perfect" temperature gradient. When you know the theory behind the standard "theoretical plate" analysis, you will understand how the heat of evaporation and condensation are used within the column and why it would be a disaster to make it the way you think it works with external water cooling or some other form of "temperature control" as the moonshiner does.

Again no heat is removed from the column (except by the exit flow of hot liquid and or vapor at the top). I.e. there is no external cooling / "temperature control" for condensing the vapor in a commercial distillation tower. The heat of condensation in one theoretical plate supplies the heat of evaporation to the next, but of course these "theoretical plates" do not really exist, except in the detail analysis of how it works.
 
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So the temperature control is inherent. It is still there. It can still be overheated if someone finds a way to crank up the heat too high. Someone had still better be watching the gauges. I appreciate the fact that the scheme is fool-resistant.
 
MetaKron said:
So the temperature control is inherent. It is still there. It can still be overheated if someone finds a way to crank up the heat too high.* Someone had still better be watching the gauges. I appreciate the fact that the scheme is fool-resistant.
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That is a silly, confusing, extension of the concept of "temperature control" to include the inherent boiling temperatures, which nature controls, not man. Yes, I admit nature does “control” water to boil at 100C but calling that “temperature control” is silly and confusing. Simply admit that you were wrong to say that "careful temperature control is required" in industrial distillation of alcohol, which is basically continuous boiling and condensing of constantly varying vapors and condensate mixes in the distillation column, always at the temperature set by nature for the local mixture.

You had only a partial understanding and you were thinking in terms of the tubing and coils (you explicitly mentioned them) used by a moonshiner, who does exercise external temperature control, usually by cold water and because he tries to interfere with nature produces a poor separation.

Industrial scale distillation is entirely different. NO TEMPERATURE CONTROL, NO TUBES, NO COILS, but there is “heating control” during industrial distillation. (Even in your text I quoted above, there still appears to be some confusion between heat and temperature, but I am reasonable sure you know the difference and this just reflects your lack of understand of the commercial scale distillation process.)

You should not state that "careful temperature control is required" for distillation for industrial scale production of alcohol. I.e. for the differential condensation of alcohol and water vapors and the differential evaporation of alcohol water mixture, on the packing filling the distillation column, which is what the "theoretical plate" analysis is all about.

If your claim were true for a mutually soluble liquid mix passing thru a distillation column, then the same would be true of the condensation and evaporation of a pure liquid substance in a distillation column. (but of course if only one substance were there, then it would remain a constant concentration of that one component.) I.e. effectively you are saying (with your silly extension of the concept of "temperature control" to cases where the control is entirely intrinsic, done by nature.) that one must have "careful temperature control" to make steam condense to water at 100C!

For any given pure liquid or any given mix of mutually soluble liquids (like a mix of alcohol and water or a mix of benzene and toluene, etc.) there is a temperature set my nature not "controlled by man," at which the (total) vapor pressure of the liquid is equal to the pressure of the of the vapor above the surface - I.e. a temperature, set by nature at which the liquid boils (and at which a slightly different composition mix vapor condenses).

What you do control, as I told you earlier, is not the boiling temperature, but the heating rate of the liquid in the "pot." I.e. you control the thru-put or mass flowing from liquid to vapor. Nature controls the temperature at which the boiling occurs for any liquid or mix of mutually soluble liquids, like alcohol and water.

As the mixed vapors proceed thru the packing in the distillation column, the relative amount of the lower boiling temperature component constantly increases and nature is constantly setting the new temperature at which the condensing liquid still boils. Man is not controlling this temperature. If he tries to do so, he will just worsen the performance of the distillation. So the truth is just the opposite of your statement, when one is speaking of the commercial production of alcohol instead of the moonshiner's method you were wrongly assuming of how commercial scale distillation works / is done.

I think you are now beginning to understand, no longer fully ignorant, but I still recommend you get a book that tells you about the "theoretical plates" in a commercial distillation tower. (And forget what you know about the moonshiner's method when discussing distillation of alcohol on an industrial scale - that has already misled you enough!)
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*This is true, but you are speaking of "thru-put" not "temperature" control. As the thru-put is increased, the performance, measured in "theoretical plates," of the distillation tower goes down. I.e. the emerging vapor or liquid taken from the top of the tower will have more of the higher boiling point component. - I do not feel like going into more subtle points related to the existence of eutectics just now - read that in a book.

I should also note that in my work in this field so many years ago it was toluene, not carbon tetra chloride as I stated earlier, that I mixed with the benzene. They have very nearly the same boiling point and are often used to test the maximum performance of a distillation system, as I was doing so long ago that initially I forgot what I did in detail. (I remembered the benzene because a few year later, it became known that it is toxic. Quite a few times, when opening the hot pot, I unintentionally inhaled some. Fact that it is often in the glue that some really stupid kids intentionally inhale, in much greater volumes, helped me not worry much about this exposure.)
 
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In Sao paulo, Brazil at 7PM local CNNi (i for international edition) used all of its 30 minute program, called "Insight," to report on alcohol, mainly facts from Brazil's 30 years of experience with driving cars on it." I even learned somethng from it - namely VW of Brazil will not make any more gasoline engines here. All VWs will be "flex fuel" - any ratio of gas and alcohol and that the total cost of these engines is only $100 dollars greater (where I now buy my alcohol fuel it is exactly half the price of gas so I save more than $100 every 3 months filling tank with 100% alcohol.) US's "E85 cars" are still 15% gas.

There was only one error in the program, that I noticed. I hope it is available in CNN of USA also - try to see it. (Error is one expert's statement that corn is most the most efficient source. - He was thinking of the those used in US. - For example, the net energy yield of sugar cane alcohol in Brazil is about 8 but only 1.1 with Iowa corn. Both corn and sugar cane are among the few crops that use the more efficient four carbon step photo sythensis process, but sugar cane is more efficient at removing the CO2 from the air so it is the most efficient even if only considering the capture of sun light and neglecting the huge fossil input (fertilizers etc) required to grow corn in Iowa's short summers. The residue from cane also makes both good fertilizer and acts as a pesticide. - Corn residue does not, but both can be feed to cattle.

Program is full of facts - watch it if you can.
 
Summary of article on corn based ethanol in tomorrow's New York Times:

Expect to pay higher taxes (for the subsidies) and higher food prices while big agri-business gets richer.
Article ends with:
"With oil prices at $70 a barrel sharply lifting the prices paid for ethanol, the average processing plant is earning a net profit of more than $5 a bushel on the corn it is buying for about $2 a bushel, Mr. Basse said. And that is before the 51-cent-a-gallon tax credit given to refiners and blenders that incorporate ethanol into their gasoline. It is truly yellow gold" See: http://www.nytimes.com/2006/06/25/b...cf7f34&ex=1308888000&partner=rssyahoo&emc=rss

Also in NYT report:
"Despite continuing doubts about whether the fuel provides a genuine energy saving, at least 39 new ethanol plants are expected to be completed over the next 9 to 12 months..."

"...ADM has not lost interest in promoting ethanol among farm organizations, politicians and the news media. It is by far the biggest beneficiary of more than $2 billion in government subsidies the ethanol industry receives each year, via a 51-cent-a-gallon tax credit given to refiners and blenders that mix ethanol into their gasoline. ADM will earn an estimated $1.3 billion from ethanol alone in the 2007 fiscal year."
{Billy T adds: NOT included is the subsidy given to corn growers or more than half of all farm subsidies! ADM=Archer Daniels Midland}

"While ADM has pushed ethanol, rivals like Cargill* have been more skeptical. To Mr. Staley, ethanol is over promoted as a solution to the nation's energy challenges, and the growth in production, if unchecked, has the potential to ravage America's livestock industry and harm the nation's reliability as an exporter of corn and its byproducts.

"Unless we have huge increases in productivity, we will have a huge problem with food production," Mr. Staley said. "And the world will have to make choices. ....analysts doubt whether the scientists and farmers can keep up with the ethanol merchants."{Remainder by Billy T, not NYTimes}

Looks like big oil must share space on back of US tax payers who will not be eating beef. Do you think you can carry the load, or is it time to clean out Washington, end alcohol import quotes, and end the 54 cents per gallon import duty so Brazil can sell you alcohol at about 60% of what you are paying now for gasoline?
................................................................Again I ask: HOW DUMB CAN US VOTERS BE?................................................................
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*Gargill is privately held. Annually, 100s of millions of your tax dollars Cargill collects go basically to a family group as Gargill has no shareholders. ...........I have no doubt many return to Washington politicians (of both parties) so I guess it is all fair. :rolleyes: ...... What do your think?
 
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Just one specific reason why you will pay more for your food as a result of growing corn for alcohol instead of importing alcohol from areas where it is much cheaper to produce:

From:
http://news.morningstar.com/news/PR/M07/D05/NYW099.html

"...Under the agreement, AGRI-Bunge would be the exclusive originator of corn for the plant. In a separate agreement, Bunge North America has agreed to market the ethanol and the dried distiller's grain (DDGs) that would be produced by the facility. The proposed site would be located on 100 acres just north of U.S. Route 30 near the elevator operated by AGRI-Bunge. The 108-million gallon per year plant would require 40 million bushels of corn from area farmers. ..."

There are 39 of these plants now in construction in US (but not all by Bunge)!


In post before this one you can see that you will pay more taxes to support big agri-business via fram subsidies (10 billion dollars annually for corn) plus a 51cent/ gallon subsidy to the industries that convert the corn to alcohol.

I.e. "your" LOL government is:

(1) making your taxes higher than need be.
(2) making your food more expensive than need be.
(3) protecting inefficient producers with 54cents per gallon import duty on imported alcohol.
(4) annually transferring 20 billion dollars of your taxes to some of the richest people in US, such as the Cargill family, and other generous campaign contributors.
(5) making your cost of driving about 40% higher than it need be.

Be sure to vote for them next time. - You must "stay the course" :rolleyes:

More in thread "How DUMB can US voters be?" of the politics forum.
 
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crazy151drinker said:
Fusion plants to power hydrogen plants. Thats the only thing that will solve it.
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Fusion power, is a long time into the future (except for the natural reactor, called the sun). Even if it is possible to control, the economics are very doubtful. True, the fuel MAY cost less than coal, but it is not free, (some details later), and we already have electric power entirely free from any fuel cost. (Hydropower). Unfortunately, most (at least 80%) of the cost of electric power is the capital invested to produce and distribute it.

The capital cost of a coal plant and a fusion plant will have a lot in common. For example, both will require: steam generators, (which include the heat input surface, usually many iron pipes in a heat exchanger), steam turbines, cooling towers, and electric generators, so their difference in production cost is in how they get the heat to make the steam. That is what determines their relative cost advantage. Most everyone, like you, ignore this simple and obvious fact.

In the case of coal used to produce heat:
The heat production requires (in addition to coal at plant):

(1) a coal conveyer belt, (Section near furnace is usually made of steel links)
(2) a fire brick lined combustion chamber, and
(3) a tall brick chimney.

COAL SUMMARY: Nothing very expensive or requiring significant design and development costs.

In the case of fusion used to produce heat:
The heat production requires (D-T fusion assumed)*:

(1) Tritium production (half-live around 11years as I recall) it will no doubt be made from lithium by neutron bombardment. (Getting some of the neutrons from the D-T fusion, but this is tricky as they will also make most materials they pass thru radioactive and that also adds a lot of expense as handling many radioactive materials, in addition to the radioactive tritium, will not be cheap.)
(2) Processing large volumes of water to separate out the small component that is Deterium. This can not be done chemically as D and H (hydrogen) are chemically identical. Perhaps all the water is converted to steam and kept hot all the time it is being pumped thru a gaseous diffusion plant. Perhaps some centrifuge technology developed for enrichment of uranium can be used. This requirement is not discussed much, but all solution require a lot of electric power and and both types of separation facilities are expensive.
(3) Now that radioactive fuel is available, it must be (a) injected thru the magnetic confinement systems and (b) heated to about 100,000 degrees. Not cheap. Probably part (b) is not a problem after start up as it can enter an already running reactor and be heated by the fusion going on there, but remember we are comparing capital cost. Thus, even if the heating is required only once in 30 years, you still must pay for the equipment that can do it.
Part (a) will be costly also. The D & T must be neutral atoms to cross the confining magnetic field (and even then some will get ionized by the UV coming from the fusion) so they must have high speeds to get in before all are ionized. Some will interact with the field once they are ionized, perhaps destroying its ability to confine, but probably this problem is solvable, but expensive. To get them up to the high injection speeds required, they need to be accelerated and this almost certainly will require some sort of particle accelerators, at least similar to those expensive ones used for high energy physics research. That is the D & T must be ionized, accelerated, then neutralized again - not cheap.
(4)Just getting the fuel in will be as costly as all the coal system's bricks above so I will not tell much about the liquid nitrogen production (assuming the magnets do not require liquid helium), which keeps the the supper conducting magnets cool or the expense of those magnets or the very strong structure that hold the magnets together (not steel as the neutron flux would make it too radioactive, possibly titanium as can take high temperatures and I think not get too radioactive) or the pumps used in many different systems incuding pump which moves the liquid lithium near the neutron flux for production of tritium, or the nature of the pipe material for the flowing lithium that will not be dissolved by hot lithium and that will not get too radioactive or brittle under the neutron flux, or in the nature of the material which can contain the water becoming steam with out becoming too radioactive or brittle. - Perhaps there can be an extra heat exchange loop I.e. Neutrons heat the liquid lithium, (while making tritium) and then another heat exchange transfers the heat to the steam forming heat exchanger pipes, which then need not resist the neutron flux, but an additional heat exchange loop will certainly increase the cost and lower the efficiency.

Did I forget to mention that there must be a system to separate the tritium from the liquid lithium? - No matter, there are lots of other costs I did not mention, many associated with, extra site selection delays the "greens" add to any nuclear facility**, security, radioactive materials disposal at closure, control room and system costs, etc. for the plant and the safety, training, clearance investigations, etc. of its workers.

FUSION SUMMARY: Everything is very expensive (compared to bricks) and still requires a huge investment in design and development.

FINNAL SUMMARY: The capital cost of fusion power will probably be at least 50 times greater than coal power. (Increasing your electric bill by more than 40 times.) The only thing that may keep fusion power from being so costly is that there is still a good chance it is impossible (to control in less than sun-size reactors) in the steady state; But dream on and ignore the simple fact that the cost of your power is mainly capital.

I spent ~15 years of my professional life working on the “Controlled Thermonuclear Reactor, CTR, problem” and years on my experimental Ph.D. which used a plasma because I was idealistic and wanted to help solve the CTR problem. Do not feel too bad if you can not see the obvious because of your dream. - look how long it took me!
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*There are other fuel for fusion, but the D-T process is by far the cheapest and easiest to make work, so I assumed that one.

**this is the main reason there have been no new fision plants in more than 30 years, even ordered in US. Ten year approval delays has made them economically unattractive. It initially seemed that: "Fission power is too cheap to meter." (Original idea was just a fixed monthly fee for each home as the meter would add to much to the cost of almost free power to all homes). The "greens" have change this to: "Fission power is too costly to build"). Thank them next time you pay your bill. :rolleyes:
 
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"The possibility of mining the moon for its Helium-3 is thought to be a major motivator behind the Chinese space programme. Helium-3 has great potential as a non-polluting fuel source, but there is virtually none on Earth. The moon, meanwhile is relatively rich in the isotope. Although technology to exploit helium-3 is not yet in place, its value as a replacement for oil and gas could be enormous."

http://www.theregister.co.uk/2006/06/19/china_lunar_plans/

Perhaps another power source?
 
kmguru said:
"The possibility of mining the moon for its Helium-3 is thought to be a major motivator behind the Chinese space programme....
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Your post is NOT a distortion of your reference, but neither you nor the reference give the slightest reason why He3 is this magic fuel or should be found on moon.

If you would like to suppy reasons for either, I would be interested. If you think it would not ecape into space, when normal He4 readly does so from Earth, why?
What is reason it is there?
Does answer to that have anything to due with the bombardment of atmospher free moon? (gravity too weak to even hold much heaver gases)? Note all bombardment from single atoms or protons to multi-ton asteroids, relase so much energy that hot vapor is produced (locally blasting out and melting a crater much larger than their own cross-section)

How 'bout some support for what to me seems about as silly an idea as I can think of when one compares the energy cost of bringing X grams of anything from the moon surface (not to mention the "mining") back to Earth against its energy content.
 
To Kmquru (and Vega et al.):
Billy T said:
....neither you nor the reference give the slightest reason why He3 is this magic fuel or should be found on moon.
... Note all bombardment from single atoms or protons to multi-ton asteroids, relase so much energy that hot vapor is produced (locally blasting out and melting a crater much larger than their own cross-section)
How 'bout some support for what to me seems about as silly an idea as I can think of when one compares the energy cost of bringing X grams of anything from the moon surface (not to mention the "mining") back to Earth against its energy content.
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Thanks for the reference.

I will withdraw my last comment about the economics, silly idea, etc., however, I think it still true, but I am not as confident about this as when I first posted. He3 may be the only thing worth the cost of transport back to Earth. (My main concern is that only one in 10.000 of the He atoms, ACCORDING TO YOUR REFERENCE, is He3, so not only will you need to heat a lot of moon rocks to liberate helium, you will need some sort of mass spectrograph separator operating on the moon to avoid the cost of hauling 99.99% pure "trash" back from the moon. (Actually, problem is very much worse as I explain later - quickly look at the bold sentence, just before the final “PS”!!!!)

Considering that the separation of U235 from U238 could also be done by with mass spectra graph, but is not, a gaseous diffusion plant or large centrifuge enrichment facility is very likely cheaper. Note, however, that both these approaches are so expensive that few nations can afford them and they produce only a Kilogram or less per week not the 25tons per day your reference speaks of! - Thus, I am now only 99% sure it is the silliest idea I have ever heard of.

However, the economics of non-existent, quite possibly impossible, concepts is tricky so I will turn to my other, more serious, “is it even possible” concern also reposted above:

The moon keeps the same face turned to Earth. Thus every longitude of it is directly under the noon day sun once each month for many hours. (360 degrees /28 days = 12.8 degrees per day angular movement) As 15degrees (of Earth rotation) is one hour this 12.8 degrees means that for more than two days on the moon the sun is between "11 O'clock and 1 O'clock high in the sky" - must get awful hot on the moon surface with the sun almost exactly over head for more than two Earth days. Perhaps you will Google etc and tell me how hot.

Thus, there will be considerable diffusion of any Helium that has been absorbed on the moon surface, especially as the moon dust it is in is exposed to high vacuum. Helium is very mobile - why it is used to find the tiniest leak in a vacuum system. So, I see little reason to expect any is there. Your reference seems to be ducking this question by noting that the bombardment of the moon by small meteors etc will mix the surface dust absorbed He deeper, (and thus is thermally insulated) but this idea is in strong contention for second place as the "silliest idea" I have heard of. True fine dust in a vacuum probably does make good insulator (strong thermal gradient) when sun is at "high noon" for more than two days, but these meteorite impacts will surely liberate any absorbed He as they even vaporize the absorbing dust and rocks!

SUMMARY: I still think this is economically very silly even if the He3 is there, which I strongly doubt. Note also that the monthly heating of the surface will preferentially liberate He3 compared to normal He4. Therefore, if there is any He3 it is very likely to be not the 1 part in 10,000 of the solar wind, but more like 1 part in 10,000,000! - A plant that can separate 25 tons/ day of He3 from such poor "ore" is likely to be bigger than the moon!

PS - I would love to be wrong on this. I have long hoped that the DT fusion reaction is only a "match" to light others so that mankind can get to a reaction like D-He3 were all the energy release is in charged particles (a these temperatures the He is fully ionized) because then, all the energy can, in principle, be converted to electric power. All you need do is make the charged particles into a beam (easy - in fact natural in a magnetic mirror) and then let it work on a retarding electric potential field (The D-He3 reaction porduct are both positive, but still must be separated first, as the potential that stops them or recovers all their KE is different. They will drag electrons with them also so it is much more complex, but I think can be done. Sure would be nice to avoid the Carnot limits on conversion efficiency.)

I also note your reference (and his references) make an extreme point of insisting that this future power system must be a private operation and not a governmental, effort. - Quite honestly, I think this is a scheme to "fleece investors," but one of the better ones of that type I have seen. - Everyone initially concerned will be dead long before it collapses! - I will give your 100 to 1 odds that it does collapse before 2100, but you send me your bet money now. :D I also offer to all to predict the sex of your yet to be concieved child, with 110% refund if I am wrong, but again require payments up front.)
 
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Lunar He-3 is pretty much pure He-3 from the solar wind, not a mixture that is mostly He-4. The decay of uranium produces He-4. I don't know how the sun produces He-3. Different processes.

I suspect that a working fusion plant would cost a hundred times less if funded by private investors.
 
MetaKron said:
Lunar He-3 is pretty much pure He-3 from the solar wind, not a mixture that is mostly He-4. ... I don't know how the sun produces He-3. ...
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All He3 is 100% He3, not "pretty much." Lunar He3 is no exception. - You must be very confused or perhaps you are postulating some local source? (Not sure how to read your statement. What do you mean?)

As far as the fraction of the solar wind He that is He3, the 1 part in 10,000 is not my estimate but taken direct from Kmguru's reference.

I too do not know how the sun produces any. I would have expected that the nuclear reactions in the sun should be able to burn up this fuel. I.e. this He3 fuel is what his references plan to "burn" in nuclear fusion plant on Earth.

However, as I am not an expert in this area, I will accept their one part in ten thousand of the solar wind He is He3. Perhaps, it is primordial in origin, not produced in the sun. Certainly, it comes from the most outer layers of the sun if it is part of the solar wind. That region may be mainly the primordial mix of Hydrogen and Helium isotopes, except for the fact that some is from earlier stars. (We are all "star dust" in that the iron in your blood was once part of a star. Etc.)
 
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