You'd be better off with a heat pipe than a glycol loop. Not only would you need only one tube, but the effective conductivity would be much higher and you'd have zero pumping power requirements.
Many of the problems with research into AIDS is that no animal reacts to the virus the same way that humans do; there are similar monkey viruses, but they do not cause the same sort (or necessarily any) disease. Ditto with Alzheimer's and a ton of other things out there.
There are already efforts to produce chimeric animals with some human genes so that they will react more like humans to drugs, diseases and even general development. There are also ethicists looking very closely at these efforts - I don't see what's unethical about making a mouse that has a breast made of human tissue, but when you start talking about making brains develop more like humans it starts getting a little iffier.
5) Think about running your empty conduit to locations near power, so you don't have to run a bunch of extension cords.
You don't really need conduit for power wiring; Romex is just fine and pretty cheap (where legal), and if you've already got a run of Romex to a box what do you need conduit for? However, you never want to run power wiring in the same conduit as copper data, video or audio cables (optical fiber is another matter). Aside from shorts and fire, cross-talk has the potential to put noise where you don't want it. For sensitive wiring (cables carrying RF from your antenna, f'rex) you do not even want to run them parallel to power wiring. When such wires cross, they should cross at right angles to minimize EM coupling.
You're not going to run even one room light from this. You could use it to keep your cell phone and PDA charged, but you could probably do that just as well with generators in the soles of your shoes and gain mobility in the bargain.
(Yeah, I know everyone's playing this for yucks. You can see me as a wet blanket or a straight man, your choice.)
One way is to bring things which can pull as many watts (and preferably volt-amperes as well as watts - remember, computer gear does not have a unity power factor [look it up]) as your server stuff and plug it all in. Add a safety factor, say 20%; plug your dummy load in, turn it on, see if circuits stand up.
One good dummy load would be a bag full of travel-size hair dryers. They pull roughly 1500-1700 W apiece, and they don't take much room. You could plug a whole bunch of them in and see if you lose breakers; if you have 5 KW of server demand I'd go for about 7 KW of dummy loads for testing.
Note that this is over and above checking the ampere ratings on the breakers for the circuits in question. You don't necessarily know what's upstream, but like any other part of your production system you want to stress-test it before you rely on it.
This is something I don't understand extremely well myself, but I'll hand-wave and hope that I don't get anything very wrong or confuse people either.
The size of the star (the radius of the photosphere) is set in part by the power needing to be radiated; the more power the core is cranking out, the hotter the stars outer layers get and the more they expand. Much of the mass of the star is in the core, so the reduced pressure from the expanded outer layers (they are farther away from the core so gravity doesn't pull on them as hard) does not affect the core's conditions much.
As for why the core cranks out more power when it starts burning helium, it takes higher pressures and temperatures to ignite helium. The core will contract until there is enough pressure to resist further contraction, and in a star too small to form a neutron star this either comes from heat or degeneracy pressure. A hotter core means more transferred out, so the end of hydrogen fusion results in contraction, heating, ignition of helium fusion and expansion of the outer layers from the greater heat output. Helium fusion does not release as much energy as hydrogen fusion, so the greater output is not sustained anywhere near as long; the red-giant phase of a star is much shorter than the "main sequence" phase.
Yes, a star at 2000 K radiates a lot less per square meter than a star at 5700 K like our sun, but a star with the radius of the orbit of Venus (57 million miles) has a lot more radiating surface than a star with a radius of 400,000 miles.
It's one kind of nova, not a supernova
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Exploding Neutron Star
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· Score: 4, Interesting
A supernova is the event which creates the neutron star in the first place. At least one kind of nova is associated with neutron stars; I am not enough of an astrophysics geek to be sure if the term is also associated with flares from unstable normal stars, but I would suspect so (anything that brightens enough to be a "new star" would be a nova in the old nomenclature).
Our own sun is much to small to form a neutron star. When it shedds the outer gas layers it will form a white dwarf that eventually will turn into a cold iron ball.
It'll be a carbon ball, not iron; the Sun does not have enough mass to begin carbon fusion and create signficant amounts of heavier elements. It will begin the red-giant phase when it starts fusing helium (which happens when hydrogen fusion no longer generates enough heat to keep the core from contracting further) and die when it runs out.
At that scale, influences like Van der Waals forces become far more powerful than gravity. Reading the pull of gravity with all the EM-related forces at work seems like a very, very difficult job.
Brainstorm turns into brain-fart as soon as it leaves the bounds of reality.
This is one of my pet peeves. Too many people have no concept of what's actually possible within the laws of physics, and this ignorance of (or refusal to face) reality extends to their planning and even politics. Guess what happens when you plan on something that's impossible to achieve, or support a political platform which demands it? It can get very, very ugly.
Less visibly ugly but perhaps more damaging in the long run is the amount
of thought wasted thinking about and communicating impossible or otherwise
useless schemes. Ponder the number of real problems in the world
and the amount of mental and physical effort wasted due to faulty
understandings of what has to be done to solve them. Such waste
can devastate entire societies. Native Americans
conducted elaborate ceremonies to bring about the return of the buffalo,
and look how far it got them. For more recent examples, see the
pyramid schemes which bankrupted many people in the former Soviet Republics.
For one, there is no actual need for greater than 95% purity for
fuel alcohol.
Only if you aren't planning on blending it with gasoline. If you are,
you have to remove almost all the water or the mix will separate into an
emulsion of distinct phases. Emulsified fuel was a serious problem
for the designers of flex-fuel vehicles when I last followed that stuff,
and I doubt it has become all that much easier since.
That brings us to more like 13.7%.
Reality check: a Carnot-cycle engine operating at ~1000 F (1460 R)
high-side temperature and ~40 F (500 R) low-side temperature would have a
theoretical efficiency of 960/1460=66%. In reality, a steam turbine
operating around those parameters for the superheater temperature and the
condenser temperature is about 33% efficient. Mechanical losses come
off your net rather than your gross, so your 13.7% probably falls to the
region of 2-3% if you're lucky.
If you could spend the same amount on hardware to get 33% or 3%, what
would you spend it on?
It's not great, but it does represent recovered WASTE HEAT.
You can recover metal from aluminized gum wrappers, but it's not worth
it. There are better ways to squeeze more out of the heat being
used to run the stills, starting with integrating them with powerplants
which are already dumping waste heat at nearly the necessary temperature
anyway (and burning domestically-produced fuel to do it). Buying
that steam would be a lot cheaper and vastly more efficient than buying
natural gas; if the efficiency of the plant is reduced from 33% to 32%
by the higher turbine-outlet pressure, you are talking about an increase
of 323 BTU/KWH in the plant's heat rate. At 60% heat rejection
out the turbine (a guess, assuming 8% up the stack) you would get your
33,000 BTU of steam for the distillery for a mere 1667 BTU in extra fuel.
(My calculation: at 60% rejection as turbine exhaust steam, the
33,000 BTU of steam requires 55,000 BTU of fuel to produce it and the
32% efficient plant makes 17,600 BTU of electricity in the bargain.
At 33% efficiency, the same amount of electricity requires 53,333 BTU
of fuel.)
Historical heat rates for US electric powerplants are
here.
Talk to an 8th grade science teacher (where I learned it decades
ago). Or better yet, just heat some plant matter until it smolders. That 'smoke' is the mixture of tar and methanol, ready to burn at the slightest provocation.
I know it's flammable, I'm questioning your claims about composition and
"mild heating". Anything that isn't methanol is a tar? What
happens to the nitrogen, does it become nitrate, ammonia or something else?
What kinds of temperatures do I need, and under wha
Certainly, the condenser stage of an ethanol still can't be effectively fed back to the boiler stage, but it can power other processes in the distillery.
No it can't. There is not enough delta-T to run a worthwhile heat engine.
If stirling engines were produced in significant quantities, they would be effective way to capture the waste heat to provide electricity for everything from pumps and lighting to forklift batteries.
You may have heard of thermodynamics, but you obviously have not studied it or you would not have made that statement.
A Stirling engine is not a magic device. Its limit is the Carnot efficiency, which no real engine can actually reach. According to the first Google hit I got, ethanol boils at 78.3 C at sea-level pressure; in a vacuum still such as you would need to get more than 95% purity, the temperature would be even lower. At 50 C still condenser temperature and 30 C outside temperature you have precious little delta-T just to move the heat flow. Even if you could get lossless heat transfer the Carnot efficiency of an engine running on that heat flow would be (323-303)/323=6.2%. In practice, it would be stupid to try; you can make toy Stirling engines which run on minuscule temperature differences, but they do not produce useful amounts of work.
Once you've sent the heat to the still (maximum temperature 100 C), you can forget the idea of recovering work from it. The place in the cycle where this is practical is at the high-temperature end, where you can generate steam at 200-500 C and drop it through a turbine to low temperature and pressure. The exhaust steam can heat the still. If you are really smart you will heat the steam boiler with the exhaust from a gas turbine operating at 1000 C or so, and skim useful work out of the heat flow not once but twice.
The waste heat might also be a fine way to warm the fermentation tanks.
That is about all it might be good for. Other uses which spring to mind are heating of methane digesters (if the ethanol plant is integrated with a feedlot to employ the fermentation solids and the manure is processed for fuel gas) and winter heating of greenhouses for off-season vegetables.
For example, reletivly mild heating of most plant waste will yield a watery mixture of methanol and tars. The nitrogen content is left intact as well as the fiberous structure.
After finding so many obvious misconceptions in the rest of your post, I'd like you to point me to some documentation for this claim. Not that I disbelieve it (thermal depolymerization has been in the news enough to take it very seriously), but I would rather have facts without you filtering them.
I was thinking the same thing. H2O2 is not a particularly powerful (high-impulse) fuel, but if you could refine it you could use it as a source of energy to make something more potent (LH2 and LOX). It would also be a great way of running a self-powered rover/hopper; if it came to a crevasse or other impassable feature, it could use rocket power to jump over it.
This assumes that the concentration is high enough to be recovered and purified using the available local energy. That may not be the case.
In the 'worst case' That is, total conversion to biofuel, that 5 BTU would come from more biofuel and/or crop waste.
It better come from crop waste, because if it all comes from the product fuel the total productivity falls by a huge amount (83% for that 1996 example; it would probably be somewhat better now, but I'll wager it's still more than 2/3).
The use of crop waste isn't quite free either. In current harvesting techniques the corn is shelled on the combine and the stalks and ears are shredded and put back on the soil. This adds organic matter and helps control erosion. If you take it away for fuel, what other inputs are you going to need to hold the soil down and maintain its quality?
Distilleries could be made a lot more efficient as well. From what I have seen, currently there is no effort made at most distilleries to recapture the heat of condensation from the produced ethanol.
Distillation of seawater often uses multiple-effect stills, but salt does not have the problematic quality of vaporizing easily. This limits the temperatures and pressures you can use for effective separation of ethanol/water mixtures, and cuts the ability to recycle heat through common techniques such as using the condenser of a high-pressure stage to heat the boiler of a low-pressure stage.
This does not excuse the distillers for failing to use techniques which are known to work, such as solar flat-panel collectors for heating stills. The temperatures are under 100 C, which works just fine with solar. If they used a concentrating "power tower" it would be feasible to generate electricity as well as process steam to run the stills.
I believe the real purpose of the subsidies is national security. They are meant to maintain reserve food production capacity in the U.S. much like paying farmers to NOT grow crops, but more productive. That capacity parallels our strategic oil reserves. If food could be stored indefinitely, we would just maintain strategic food reserves.
It may surprise you to learn that the US once DID maintain food reserves, only their avowed purpose was to stabilize prices (buying in rich years, selling in lean years) rather than any strategic goal. Farmers were paid to idle land which would otherwise flood the system with surplus food. It worked, until someone got greedy and made a big sale to Russia when stocks were low. (According to the Cato Institute, that someone was the chairman of ADM.)
If food could be stored indefinitely, we would just maintain strategic food reserves.
You don't need to store food indefinitely, you just need to cycle it through storage fast enough that it doesn't go bad. In the case of grain, this can be a matter of years if I'm not mistaken. How many years of backup do you really need?
In a worst case economic disaster, hyperinflation is driven by dependence on imports.
That's the point I was making; the entire "biofuel" system as currently constructed is highly dependent upon imports, and will fare just as badly as everything else if they were to be restricted. To be a real source of security it has to be independent.
This need not be overly difficult. For instance, if we got the "hydrogen from green algae" trick working on an industrial scale and 5% efficiency, the hydrogen could fix the nitrogen required for crop production without any fossil inputs (as might recycling of the fermentation solids as animal feed, the manure handled as input to a methane digester for further fuel production, and finally the digester effluent used as liquid fertilizer). For the distillation step solar heat would do, or byproduct steam from a steam-cycle powerplant. This would eliminate the dependence of any part of the ethanol process on imported fuels, and free much of it from fossil fuels.
What you're saying is that either the EM field is harmful, or there is no harm. This is the classic fallacy of the excluded middle; you are assuming a priori and without evidence that there is only one mode (the direct EM field) which can lead to harm.
I seem to recall reading that the people "affected" by power lines tended to live on the downwind side, leading to speculation that the HV corona effects (well-documented) might charge fine dust particles and make them more likely to precipitate out, clump up, or otherwise have greater effects in the immediate vicinity than they would otherwise. There are plenty of studies showing that e.g. PM10 particles are dangerous to people, so anything which makes them hit folks near an HV powerline more than people further away would be a mode of harm which has nothing to do with the direct influence of the EM field.
In order for those figures to be truly meaningful, they must be compared to the fuel expendature for fossil fuel production. That should include the resources to produce those oil rigs in the North Sea, the supertankers...
All of that is included in the cost of crude delivered to the refinery.
... the tanker trucks (and the fuel they consume), refining, etc.
Every BTU of energy that comes out of the pump is a BTU of energy that came from crude in the first place.
In the case of ethanol from corn, that is not true. As of 1996, there were some 5 BTU of non-renewable inputs to get 6 BTU of ethanol out of the distillery, and it does not get better from there. Even the tanker trucks which move the product gasohol are powered by petroleum diesel, not ethanol. Yet a 10% ethanol blend, representing 1/10 of 1/6 = 1/60 renewable energy, is eligible for a complete abatement of the federal gasoline tax. This is 60 * 19 cents = $11.40/gallon subsidy. It is one of the most wasteful subsidies I know. Liquefying coal or using wind power to charge electric vehicles would give us many more miles per subsidy dollar.
Further, to compare the viability of switching to biofuels, economy of scale hasto be considered. What would the biofuels cost when produced at the scale required for use as a primary fuel?
Good point. Here's another: if the current system for production of biofuels depends on fossil fuels which are becoming more costly, aren't we painting ourselves into a corner by trying to expand production of those biofuels without also changing the production methods? We used about 38 quadrillion BTU of oil in 2002, roughly half of it for motor gasoline. We also used about 23 quads of natural gas. If we tried to make 18 quads of fuel ethanol using current technology, we would need another 6 quads of natural gas just for distilling. That is more than a 25% increase over current consumption. Where would that gas come from, and how high would prices be driven?
Biofuels are free in terms of CO2 production since any CO2 released when the fuel is burned will at most equal the amount absorbed when the plants were grown.
That's assuming that the cultivation does not result in a change in e.g. soil carbon inventory. If you convert land from lumber forest to pulpwood forest, kenaf or annual crops this is probably not the case.
Personally, my suspicion is that we cannot totally convert to biofuels.
I believe this is correct as current biofuels are currently made. However, if we develop techniques such as hydrogen from green algae and bioreactors which convert hydrogen and carbon dioxide to liquids such as methanol, the net productivity could be high enough to change a lot of that.
... one situation in which the world would no longer produce enough food is if there is a large shift to biofuels. The amount of corn that would need to be grown for ethanol or biodiesel if we shift to a biofuel fleet would be staggering...
Then multiply by a large factor again. If the Chippewa Valley ethanol plant in 1996 is typical of current technology, the situation would be downright dismal; that year the plant consumed 1 gallon-equivalent (gasoline) of fossil fuels to produce a mere 1.2 gallons-equivalent of ethanol. Of 6 gallons of output, you'd have to feed 5 gallons back into the process to keep it going. Even in 2002 they report 33421 BTU of gas consumption per anhydrous gallon of ethanol. Given that ethanol has about 75% of the energy content of gasoline and gasoline is about 123,000 BTU/gallon, each gallon of ethanol requires something like 33% of its delivered energy as an input of gas. Then you have the energy demands for cultivation, nitrogen fertilizers and pesticides.
Ethanol right now is IMHO one of the least ecological fuels you can use in a vehicle, because of the way it is produced and the distorting subsidies which promote this production. #include <std_subsidy_rant.h>
There are many bad laws which might never have been passed if government had just commissioned some proper research on the matters in question and then acted in accordance with the results. There are many more bad laws which should be revoked based on research which has disproven their basis.
... like where the first 13 colonies were set up and they really didn't know how to grow their own food until the Native Americans taught them how to.
Yeah, like the natives had wheat, and rye, and oats, and apple trees, and all those other crops unknown to Westerners. <insert DUH with red circle and bar sinister here>
Whether or not California is truly a donor state depends where the cost of running Glen Canyon Dam and Hoover Dam is put. If they are charged to Arizona or Nevada (next to the dams) rather than the places the water goes, you will not get an accurate picture of how the subsidies flow.
(Not saying that they are, I have no expertise in this matter; I'm just saying that this is one way in which the truth could be obscured.)
But complaining about Federal monies spent in California rings hollow, especially given the enormous budget deficit facing California
To the extent that those deficits come from a bunch of amateurs (politicians) playing the energy markets with the taxpayer's money under rules written and approved by the legislature, those problems are entirely home-grown and do not deserve a bailout. The huge spending run-up during the dot-bomb era does not justify a bailout either.
Los Angeles can't get enough drinking water; they're draining the Colorado River dry before it reaches the sea
Not that it's particularly good drinking water. The amount of salt in it makes it inadvisable for some people (e.g. hypertensives) to drink, and this same salt requires measures to defend against salination when used for irrigation.
and still they can't get enough water.
Never mind that the sunlight falling on Los Angeles would probably be sufficient to desalinate all the fresh water they'd really need. I can't think of any reason why toilets can't be flushed with saltwater and lawns and plants watered with reclaimed graywater, can you?
Yet they grow rice in the desert!
All paid for by Federal irrigation projects, meaning taxpayers nationwide.
If California had to pay for all of this itself, much of the state would dry up and blow away overnight. And it ought to.
And we wonder why the rest of the world thinks we're idiots.
Including this native-born American. It is just one more example of how subsidies create destructive incentives.
FWIW, I think the ~$2/gallon subsidy we give oil via our defense spending is just as insane; if we charged the cost of defending ourselves and the Middle East against oil-financed extremism via fuel taxes, we would not have had an SUV craze. At $3.50 or more per gallon, there would not be enough of a market for Escalades, Hummers, Excursions and monster pickups to create the variety of models which lures people to use them as image statements (other than "I have more money than sense"), and we would be safer and richer (with a much healthier balance of payments) than we are with our hidden oil subsidies.
Phase is not the same as polarization. Radio telescopes measure phase using extremely precise clocks as references, but even if you could calculate the phase of incoming photons (at 400-terahertz frequencies?) you would still have the problem of maintaining a sufficiently precise clock at optical frequencies.
Current optical interferometers do their work using the incoming light itself. Not even the professionals are trying to measure phase information on starlight AFAIK; they would probably begin by using something like a hologram with a ground-generated reference beam, and I have not heard of that being attempted. (The current system for using an upward-projected laser beam as an artificial "guide star" for correction of atmospheric distortion is not the same; it only works for one telescope at a time.) If you consider the requirements of the job in sheer accuracy and processing power, it appears that optical interferometry without direct optical paths from all the the telescopes to the point of measurement is a long way off.
it has a high index of refraction due to its high dielectric constant. This would tend to muck up the wavefront shape of anything that reflects (rather than being absorbed).
This is one place where the solid dish is a disadvantage. If the dish was a mesh (coarse enough to let water fall through rather than being held in the holes by surface tension) this might not be such a problem.
I had thought of heat pipes, along with electric heaters, for keeping the flesh from freezing off those bones... and some guy from toasty Missouri beats me to it.
Of course, he's got a lab to try this stuff in and I don't.
If it's true that the fossil-based economy will expire by 2040 (the number quoted by my college professor)
If it's true that he said that, then your professor has missed the clue train, because the USA is "the Saudi Arabia of coal". Then there are quadrillions of cubic feet of methane locked in clathrates on the continental shelves...
The Middle East should be hitting the peak of the Hubbert curve about now, and there are alternatives waiting in the wings. When it starts becoming much more expensive to lift oil than it is now, those alternatives will start developing the economies of scale which have so far been the domain of oil. The result will be a rapid collapse of the markets for oil, along with the economies of the oil dictatorships.
It's of lower quality because it's composed of heavier molecules (tars, waxes and asphalts) or is full of sulfur and metals which have to be removed. Take the "crude" from Venezuela; it is closer to bitumen than anything you'd recognize as oil, and it has to be "cracked" into lighter fractions to be made useful. When you crack hydrocarbons you tend to get some of the carbon clumping together unusably as "petroleum coke"; the stuff might as well be coal for all the oil you can make out of it (though some powerplants burn it in place of coal because it's cheaper).
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You'd be better off with a heat pipe than a glycol loop. Not only would you need only one tube, but the effective conductivity would be much higher and you'd have zero pumping power requirements.
There are already efforts to produce chimeric animals with some human genes so that they will react more like humans to drugs, diseases and even general development. There are also ethicists looking very closely at these efforts - I don't see what's unethical about making a mouse that has a breast made of human tissue, but when you start talking about making brains develop more like humans it starts getting a little iffier.
You're not going to run even one room light from this. You could use it to keep your cell phone and PDA charged, but you could probably do that just as well with generators in the soles of your shoes and gain mobility in the bargain.
(Yeah, I know everyone's playing this for yucks. You can see me as a wet blanket or a straight man, your choice.)
One good dummy load would be a bag full of travel-size hair dryers. They pull roughly 1500-1700 W apiece, and they don't take much room. You could plug a whole bunch of them in and see if you lose breakers; if you have 5 KW of server demand I'd go for about 7 KW of dummy loads for testing.
Note that this is over and above checking the ampere ratings on the breakers for the circuits in question. You don't necessarily know what's upstream, but like any other part of your production system you want to stress-test it before you rely on it.
The size of the star (the radius of the photosphere) is set in part by the power needing to be radiated; the more power the core is cranking out, the hotter the stars outer layers get and the more they expand. Much of the mass of the star is in the core, so the reduced pressure from the expanded outer layers (they are farther away from the core so gravity doesn't pull on them as hard) does not affect the core's conditions much.
As for why the core cranks out more power when it starts burning helium, it takes higher pressures and temperatures to ignite helium. The core will contract until there is enough pressure to resist further contraction, and in a star too small to form a neutron star this either comes from heat or degeneracy pressure. A hotter core means more transferred out, so the end of hydrogen fusion results in contraction, heating, ignition of helium fusion and expansion of the outer layers from the greater heat output. Helium fusion does not release as much energy as hydrogen fusion, so the greater output is not sustained anywhere near as long; the red-giant phase of a star is much shorter than the "main sequence" phase.
Yes, a star at 2000 K radiates a lot less per square meter than a star at 5700 K like our sun, but a star with the radius of the orbit of Venus (57 million miles) has a lot more radiating surface than a star with a radius of 400,000 miles.
At that scale, influences like Van der Waals forces become far more powerful than gravity. Reading the pull of gravity with all the EM-related forces at work seems like a very, very difficult job.
Brainstorm turns into brain-fart as soon as it leaves the bounds of reality.
This is one of my pet peeves. Too many people have no concept of what's actually possible within the laws of physics, and this ignorance of (or refusal to face) reality extends to their planning and even politics. Guess what happens when you plan on something that's impossible to achieve, or support a political platform which demands it? It can get very, very ugly.
Less visibly ugly but perhaps more damaging in the long run is the amount of thought wasted thinking about and communicating impossible or otherwise useless schemes. Ponder the number of real problems in the world and the amount of mental and physical effort wasted due to faulty understandings of what has to be done to solve them. Such waste can devastate entire societies. Native Americans conducted elaborate ceremonies to bring about the return of the buffalo, and look how far it got them. For more recent examples, see the pyramid schemes which bankrupted many people in the former Soviet Republics.
Only if you aren't planning on blending it with gasoline. If you are, you have to remove almost all the water or the mix will separate into an emulsion of distinct phases. Emulsified fuel was a serious problem for the designers of flex-fuel vehicles when I last followed that stuff, and I doubt it has become all that much easier since.
Reality check: a Carnot-cycle engine operating at ~1000 F (1460 R) high-side temperature and ~40 F (500 R) low-side temperature would have a theoretical efficiency of 960/1460=66%. In reality, a steam turbine operating around those parameters for the superheater temperature and the condenser temperature is about 33% efficient. Mechanical losses come off your net rather than your gross, so your 13.7% probably falls to the region of 2-3% if you're lucky.
If you could spend the same amount on hardware to get 33% or 3%, what would you spend it on?
You can recover metal from aluminized gum wrappers, but it's not worth it. There are better ways to squeeze more out of the heat being used to run the stills, starting with integrating them with powerplants which are already dumping waste heat at nearly the necessary temperature anyway (and burning domestically-produced fuel to do it). Buying that steam would be a lot cheaper and vastly more efficient than buying natural gas; if the efficiency of the plant is reduced from 33% to 32% by the higher turbine-outlet pressure, you are talking about an increase of 323 BTU/KWH in the plant's heat rate. At 60% heat rejection out the turbine (a guess, assuming 8% up the stack) you would get your 33,000 BTU of steam for the distillery for a mere 1667 BTU in extra fuel. (My calculation: at 60% rejection as turbine exhaust steam, the 33,000 BTU of steam requires 55,000 BTU of fuel to produce it and the 32% efficient plant makes 17,600 BTU of electricity in the bargain. At 33% efficiency, the same amount of electricity requires 53,333 BTU of fuel.)
Historical heat rates for US electric powerplants are here.
I know it's flammable, I'm questioning your claims about composition and "mild heating". Anything that isn't methanol is a tar? What happens to the nitrogen, does it become nitrate, ammonia or something else? What kinds of temperatures do I need, and under wha
A Stirling engine is not a magic device. Its limit is the Carnot efficiency, which no real engine can actually reach. According to the first Google hit I got, ethanol boils at 78.3 C at sea-level pressure; in a vacuum still such as you would need to get more than 95% purity, the temperature would be even lower. At 50 C still condenser temperature and 30 C outside temperature you have precious little delta-T just to move the heat flow. Even if you could get lossless heat transfer the Carnot efficiency of an engine running on that heat flow would be (323-303)/323=6.2%. In practice, it would be stupid to try; you can make toy Stirling engines which run on minuscule temperature differences, but they do not produce useful amounts of work.
Once you've sent the heat to the still (maximum temperature 100 C), you can forget the idea of recovering work from it. The place in the cycle where this is practical is at the high-temperature end, where you can generate steam at 200-500 C and drop it through a turbine to low temperature and pressure. The exhaust steam can heat the still. If you are really smart you will heat the steam boiler with the exhaust from a gas turbine operating at 1000 C or so, and skim useful work out of the heat flow not once but twice.
That is about all it might be good for. Other uses which spring to mind are heating of methane digesters (if the ethanol plant is integrated with a feedlot to employ the fermentation solids and the manure is processed for fuel gas) and winter heating of greenhouses for off-season vegetables. After finding so many obvious misconceptions in the rest of your post, I'd like you to point me to some documentation for this claim. Not that I disbelieve it (thermal depolymerization has been in the news enough to take it very seriously), but I would rather have facts without you filtering them.This assumes that the concentration is high enough to be recovered and purified using the available local energy. That may not be the case.
It better come from crop waste, because if it all comes from the product fuel the total productivity falls by a huge amount (83% for that 1996 example; it would probably be somewhat better now, but I'll wager it's still more than 2/3).
The use of crop waste isn't quite free either. In current harvesting techniques the corn is shelled on the combine and the stalks and ears are shredded and put back on the soil. This adds organic matter and helps control erosion. If you take it away for fuel, what other inputs are you going to need to hold the soil down and maintain its quality?
Distillation of seawater often uses multiple-effect stills, but salt does not have the problematic quality of vaporizing easily. This limits the temperatures and pressures you can use for effective separation of ethanol/water mixtures, and cuts the ability to recycle heat through common techniques such as using the condenser of a high-pressure stage to heat the boiler of a low-pressure stage.
This does not excuse the distillers for failing to use techniques which are known to work, such as solar flat-panel collectors for heating stills. The temperatures are under 100 C, which works just fine with solar. If they used a concentrating "power tower" it would be feasible to generate electricity as well as process steam to run the stills.
It may surprise you to learn that the US once DID maintain food reserves, only their avowed purpose was to stabilize prices (buying in rich years, selling in lean years) rather than any strategic goal. Farmers were paid to idle land which would otherwise flood the system with surplus food. It worked, until someone got greedy and made a big sale to Russia when stocks were low. (According to the Cato Institute, that someone was the chairman of ADM.)
You don't need to store food indefinitely, you just need to cycle it through storage fast enough that it doesn't go bad. In the case of grain, this can be a matter of years if I'm not mistaken. How many years of backup do you really need?
That's the point I was making; the entire "biofuel" system as currently constructed is highly dependent upon imports, and will fare just as badly as everything else if they were to be restricted. To be a real source of security it has to be independent.
This need not be overly difficult. For instance, if we got the "hydrogen from green algae" trick working on an industrial scale and 5% efficiency, the hydrogen could fix the nitrogen required for crop production without any fossil inputs (as might recycling of the fermentation solids as animal feed, the manure handled as input to a methane digester for further fuel production, and finally the digester effluent used as liquid fertilizer). For the distillation step solar heat would do, or byproduct steam from a steam-cycle powerplant. This would eliminate the dependence of any part of the ethanol process on imported fuels, and free much of it from fossil fuels.
I seem to recall reading that the people "affected" by power lines tended to live on the downwind side, leading to speculation that the HV corona effects (well-documented) might charge fine dust particles and make them more likely to precipitate out, clump up, or otherwise have greater effects in the immediate vicinity than they would otherwise. There are plenty of studies showing that e.g. PM10 particles are dangerous to people, so anything which makes them hit folks near an HV powerline more than people further away would be a mode of harm which has nothing to do with the direct influence of the EM field.
In the case of ethanol from corn, that is not true. As of 1996, there were some 5 BTU of non-renewable inputs to get 6 BTU of ethanol out of the distillery, and it does not get better from there. Even the tanker trucks which move the product gasohol are powered by petroleum diesel, not ethanol. Yet a 10% ethanol blend, representing 1/10 of 1/6 = 1/60 renewable energy, is eligible for a complete abatement of the federal gasoline tax. This is 60 * 19 cents = $11.40/gallon subsidy. It is one of the most wasteful subsidies I know. Liquefying coal or using wind power to charge electric vehicles would give us many more miles per subsidy dollar.
Good point. Here's another: if the current system for production of biofuels depends on fossil fuels which are becoming more costly, aren't we painting ourselves into a corner by trying to expand production of those biofuels without also changing the production methods? We used about 38 quadrillion BTU of oil in 2002, roughly half of it for motor gasoline. We also used about 23 quads of natural gas. If we tried to make 18 quads of fuel ethanol using current technology, we would need another 6 quads of natural gas just for distilling. That is more than a 25% increase over current consumption. Where would that gas come from, and how high would prices be driven? That's assuming that the cultivation does not result in a change in e.g. soil carbon inventory. If you convert land from lumber forest to pulpwood forest, kenaf or annual crops this is probably not the case. I believe this is correct as current biofuels are currently made. However, if we develop techniques such as hydrogen from green algae and bioreactors which convert hydrogen and carbon dioxide to liquids such as methanol, the net productivity could be high enough to change a lot of that.Ethanol right now is IMHO one of the least ecological fuels you can use in a vehicle, because of the way it is produced and the distorting subsidies which promote this production. #include <std_subsidy_rant.h>
There are many bad laws which might never have been passed if government had just commissioned some proper research on the matters in question and then acted in accordance with the results. There are many more bad laws which should be revoked based on research which has disproven their basis.
Actually it was the reverse. With minor exceptions western agriculture out-produced the native American crops and techniques by large margins (until western crop-breeding practices produced things like modern maize)... and if you actually care about the facts, here is a good introduction which explains why this was, among many other important factors.
(Not saying that they are, I have no expertise in this matter; I'm just saying that this is one way in which the truth could be obscured.)
To the extent that those deficits come from a bunch of amateurs (politicians) playing the energy markets with the taxpayer's money under rules written and approved by the legislature, those problems are entirely home-grown and do not deserve a bailout. The huge spending run-up during the dot-bomb era does not justify a bailout either.If California had to pay for all of this itself, much of the state would dry up and blow away overnight. And it ought to.
Including this native-born American. It is just one more example of how subsidies create destructive incentives.FWIW, I think the ~$2/gallon subsidy we give oil via our defense spending is just as insane; if we charged the cost of defending ourselves and the Middle East against oil-financed extremism via fuel taxes, we would not have had an SUV craze. At $3.50 or more per gallon, there would not be enough of a market for Escalades, Hummers, Excursions and monster pickups to create the variety of models which lures people to use them as image statements (other than "I have more money than sense"), and we would be safer and richer (with a much healthier balance of payments) than we are with our hidden oil subsidies.
Current optical interferometers do their work using the incoming light itself. Not even the professionals are trying to measure phase information on starlight AFAIK; they would probably begin by using something like a hologram with a ground-generated reference beam, and I have not heard of that being attempted. (The current system for using an upward-projected laser beam as an artificial "guide star" for correction of atmospheric distortion is not the same; it only works for one telescope at a time.) If you consider the requirements of the job in sheer accuracy and processing power, it appears that optical interferometry without direct optical paths from all the the telescopes to the point of measurement is a long way off.
This is one place where the solid dish is a disadvantage. If the dish was a mesh (coarse enough to let water fall through rather than being held in the holes by surface tension) this might not be such a problem.
Of course, he's got a lab to try this stuff in and I don't.
The Middle East should be hitting the peak of the Hubbert curve about now, and there are alternatives waiting in the wings. When it starts becoming much more expensive to lift oil than it is now, those alternatives will start developing the economies of scale which have so far been the domain of oil. The result will be a rapid collapse of the markets for oil, along with the economies of the oil dictatorships.
It's of lower quality because it's composed of heavier molecules (tars, waxes and asphalts) or is full of sulfur and metals which have to be removed. Take the "crude" from Venezuela; it is closer to bitumen than anything you'd recognize as oil, and it has to be "cracked" into lighter fractions to be made useful. When you crack hydrocarbons you tend to get some of the carbon clumping together unusably as "petroleum coke"; the stuff might as well be coal for all the oil you can make out of it (though some powerplants burn it in place of coal because it's cheaper).
... it makes neutrons that are waaaay too convenient for people who want to turn uranium into bomb material. Also noted here by a previous poster.