A new source for ethanol: Coal

[Blau]

I just found this interesting article on Cnet's news.com
(copy&paste begins here since I can't post links)

"Ethanol from coal? If it works, it could solve three major problems for the energy industry.

Researchers at Louisiana State University, along with colleagues from Clemson University and Oak Ridge National Laboratories, are trying to develop catalysts and processes that would allow energy companies to convert coal into a mix of carbon monoxide and hydrogen, and then convert those gases into ethanol.

The ethanol could then be used as a liquid fuel additive or, alternatively, shipped as a liquid and then be converted into hydrogen for hydrogen fuel cells, said LSU's James Spivey, who is heading up the project.

Right now, ethanol is primarily made out of corn or sugarcane. It's expensive and time-consuming to make, a problem. A gallon of ethanol derived from plant matter also only has around two-thirds of the energy content of a gallon of gas. A gallon of ethanol derived from coal-created synthetic gases could provide more energy.

"You could avoid an energy penalty" with coal ethanol, Spivey said.

The U.S. is also sitting on massive reserves of coal that dwarf even the oil reserves of Saudi Arabia. Coal-fired power plants, however, are a major source of pollution. Using coal (in tightly controlled factory situations) to make ethanol would solve the issue of how to exploit the domestic coal supply in a way that doesn't harm the environment drastically, problem number two.

Problem number three, of course, is the hydrogen transportation problem. Hydrogen corrodes pipelines and the extremely small size of hydrogen molecules makes it tough to come up with pipelines that don't leak. Transporting it as a liquid helps solve that.

Now they just have to find the catalysts.

The Department of Energy and ConocoPhillips are underwriting the $2.9 million cost of the project.

Meanwhile, others such as Silverado Green Fuel, are looking at ways of making liquid fuels with coal particles."

(end copy&paste)

I'm personally a bit skeptical about this (which is why I am here of course) and for some reason this article is setting off water-powered-car-esque bells in my head.

Can anyone with a better understanding of chemistry explain to me how carbon monoxide and hydrogen gas can be converted into ethanol and whether or not there would be energy use equal or greater than the energy used up in the the processing of coal?

I guess that's all I have to say for now and I look forward to any insight.

[Gord_in_Toronto]

I'm having trouble with:
A gallon of ethanol derived from plant matter also only has around two-thirds of the energy content of a gallon of gas. A gallon of ethanol derived from coal-created synthetic gases could provide more energy.

Does Spivey also think a pound of lead is heavier than a pound of feathers? :confused:

[mhaze]

Problem number three, of course, is the hydrogen transportation problem. Hydrogen corrodes pipelines and the extremely small size of hydrogen molecules makes it tough to come up with pipelines that don't leak. Transporting it as a liquid helps solve that.


Yep, no kidding.

We move a lot of hydrogen around in pipelines right now.

It's in a dense packed chemical form called oil, or gasoline.

[Just thinking]

Now they just have to find the catalysts.

And it wouldn't surprise me one bit if platinum was a key player.

Problem ... Platinum = $$$$

[Goshawk]

I'm having trouble with:


Does Spivey also think a pound of lead is heavier than a pound of feathers? :confused:

I think that what they're getting at is that if it might be cheaper to manufacture a gallon of ethanol out of coal than out of corn, then a gallon of coal-derived ethanol could "provide more energy" overall, since its production cost would be less to begin with.

[fuelair]

I think that what they're getting at is that if it might be cheaper to manufacture a gallon of ethanol out of coal than out of corn, then a gallon of coal-derived ethanol could "provide more energy" overall, since its production cost would be less to begin with.I have been on another thread (energy of bodies, dead or alive - one of macdaddys) and we really need to be careful on the science stuff to avoid confusion. The cost factor is correct, but for people who cannot follow why a dead body and a living body of the same mass must have the same total energy, the statement could make them think a gallon of one derivation ethanol might have more/less energy than a gallon of different derivation.

[joobz]

I have been on another thread (energy of bodies, dead or alive - one of macdaddys) and we really need to be careful on the science stuff to avoid confusion. The cost factor is correct, but for people who cannot follow why a dead body and a living body of the same mass must have the same total energy, the statement could make them think a gallon of one derivation ethanol might have more/less energy than a gallon of different derivation.
be careful Fuelair, Total energy and useful energy are not the same things. And you are mixing volume and mass which can add to the confusion. (I know you know the differences, I'm simply pointing out that it's easy to write something with inherent assumptions which may confuse others)

[Gord_in_Toronto]

be careful Fuelair, Total energy and useful energy are not the same things. And you are mixing volume and mass which can add to the confusion. (I know you know the differences, I'm simply pointing out that it's easy to write something with inherent assumptions which may confuse others)

Confused me! :confused: Though I could guess what the intended meaning was. :blush:

[joobz]

Confused me! :confused: Though I could guess what the intended meaning was. :blush:
sorry, I'm guilty of my own warnings.

When we talk about the energy in enthanol, we are really only talking about the heat of combustion. that is the amount of energy release from burning the material (which comes from the breaking of the ethanol bonds). This is a different thing than asking for how much energy is totally in the ethanol molecules. For that, you'd have to add up all bonds in ethanol and calculate the energy contained in each bond. this value is called the heat of formation, and is the amount of energy it takes to make that molecule from elements in their standard states. Heat of combustion is the difference between the heat of formation of what's being burned and the heat of formation of carbon dioxide and water.

beyond that, in that one gallon of gas, you also have enthalpy (which depends upon the materials specific heat and temperature).

[Dilb]

Can anyone with a better understanding of chemistry explain to me how carbon monoxide and hydrogen gas can be converted into ethanol and whether or not there would be energy use equal or greater than the energy used up in the the processing of coal?

First use the Fischer-Tropsch process (http://en.wikipedia.org/wiki/Fischer-Tropsch_process), which gives you some combination of large chain hydrocarbons (i.e. oil). Then steam crack that into ethylene (http://en.wikipedia.org/wiki/Ethylene), then hydrate ethylene into ethanol. All these steps will obviously waste energy, but since the energy from coal is 'free', it still produces usable energy overall.

I guess they're hoping to simplify this process. However, gasoline is a much better fuel than ethanol. This whole thing strikes me as nothing more than a way to make coal look like less of the environmental disaster that it is. Despite all the blather, this is nothing more than a complicated way of burning coal.

A gallon of ethanol derived from coal-created synthetic gases could provide more energy.

This sounds like they are trying to say "it takes a gallon of gasoline to produce a gallon of ethanol from corn, which wastes energy. This process would produce energy".

This relies on two deceptions. First, there was a study that showed that producing ethanol from corn was a waste of energy, as growing the corn and distilling the alcohol used more energy than the alcohol provided. This is generally regarded as no longer true. It's not a lot, but you do gain some energy. My friend tried to estimate it as part of his undergrad engineering thesis, and he figured the gain was something like 20% to 50%.

Second, they are ignoring the energy from the coal. The thinking essentially goes "we weren't going to burn the coal, but we would burn the oil. Therefore, we don't need to consider the energy of the coal, because we aren't losing it. Therefore, we are producing energy".

[rwguinn]

<<snip>>

Second, they are ignoring the energy from the coal. The thinking essentially goes "we weren't going to burn the coal, but we would burn the oil. Therefore, we don't need to consider the energy of the coal, because we aren't losing it. Therefore, we are producing energy".

And as we all know, coal is just lying there on the ground in massive quantities, just waiting for us to pick it up and use it. No energy required there, either...

[Dilb]

And as we all know, coal is just lying there on the ground in massive quantities, just waiting for us to pick it up and use it. No energy required there, either...

Well obviously there are logistics to anything, but even if we allow an assumption like that it's still an incredibly weaselly argument they're making. It's wrong, but it's wrong in such a way that it's hard to pick out any one point as actually being a lie, particularly when explaining it to non-sciency types.

[mhaze]

The premise is

Coal Bad
Ethanol Good

The conclusion is

More ethanol Gooder!
:confused:

[Blau]

And as we all know, coal is just lying there on the ground in massive quantities, just waiting for us to pick it up and use it. No energy required there, either...

That's partially the reason I am skeptical of this.
They need to process the coal yet now they suggest processing further will save energy?



I guess they're hoping to simplify this process. However, gasoline is a much better fuel than ethanol. This whole thing strikes me as nothing more than a way to make coal look like less of the environmental disaster that it is. Despite all the blather, this is nothing more than a complicated way of burning coal.


They must realise that ethanol being less efficient than gasoline would mean they would need to mine 1.333... times as much coal as previously needed for the same amount of energy output, which seems a bit ridiculous.

I think (hope) that this is one of those news stories that will get swept under the rug and not actually come into fruition.

Unless of course I'm horribly misinformed about it all, in which case, more power to them!

[rwguinn]

Well obviously there are logistics to anything, but even if we allow an assumption like that it's still an incredibly weaselly argument they're making. It's wrong, but it's wrong in such a way that it's hard to pick out any one point as actually being a lie, particularly when explaining it to non-sciency types.
Ya.. well-
If you are going to charge the planting, growing, harvesting and processing of biologicals (corn, wheat, barley(yum!)) against their ethanol yield, it seems only fair to charge the digging, blasting, hauling, elevating, crushing, processing, and environmental/human resource costs against coal.
I'm kinda picky that way.

[Rob Lister]

That's partially the reason I am skeptical of this.
They need to process the coal yet now they suggest processing further will save energy?

They must realise that ethanol being less efficient than gasoline would mean they would need to mine 1.333... times as much coal as previously needed for the same amount of energy output, which seems a bit ridiculous.



This is more a problem of poor reporting (in terms of actually evaluating the claim). It could be well worth while.

Note the part I bolded. What are you comparing with? 1.333 times the coal might be cheaper.

Consider that wholesale coal runs ~$65 a st, which works out to $1.00 for 375Kbtu (assuming ~12kbtu/lb) whereas wholesale gasoline runs ~$2 a gal, which works out to $1.00 for 75Kbtu.

p.s. check my conversion and math....regardless, the point is what I'm making.

[Rob Lister]

Ya.. well-
If you are going to charge the planting, growing, harvesting and processing of biologicals (corn, wheat, barley(yum!)) against their ethanol yield, it seems only fair to charge the digging, blasting, hauling, elevating, crushing, processing, and environmental/human resource costs against coal.
I'm kinda picky that way.

I agree, which is why I find the almighty buck to be the best metric. Not perfect, since subsidies screw that metric too.

[phildonnia]

One of the claimed advantages of ethanol is that the CO2 produced from burning it is offset by the CO2 absorbed by the plants that produced the ethanol. Ethanol from coal would completely miss the point.

[Jimbo07]

Ya.. well-
If you are going to charge the planting, growing, harvesting and processing of biologicals (corn, wheat, barley(yum!)) against their ethanol yield, it seems only fair to charge the digging, blasting, hauling, elevating, crushing, processing, and environmental/human resource costs against coal.
I'm kinda picky that way.

errr...

Fuel lifecycle analyses are complicated. An intellectually honest analysis/comparison will try to compare like with like. So, you have to define what you mean by "well-to-wheels," in either process. Part of this is determining your basis of comparison. The most strictly honest is KJ of process energy per KJ of energy delivered at the pump. A useful measure is KJ of process energy per Km driven, because you may get some benefit like enhanced combustion.

When looking at energy efficiency, it can be found that conventional oil and gas gives about 0.3 KJ process/KJ pump, whereas ethanol from grains (avg. wheat and corn) might be about 0.75 KJ process/KJ pump. Both processes are energy efficient (despite the outright lies you might have heard about ethanol), but clearly, conventional sources are 'cheaper.'

If a cheap, clean coal conversion can be found, then you'd be laughing! This is not necessarily woo. EtOH is made from C, H and O (empirical C2H6O), all of which are found in CO and H2.

ETA: phildonnia, CO2 emissions are a separate (if not totally unrelated) issue from energy economics. It just depends what your policy makers (or voting public) are prioritizing...

[pgwenthold]

But if its not about CO2 emissions, why not just find a way to convert coal to gasoline? It basically needs more H2, but you can get there.

[Dilb]

Ya.. well-
If you are going to charge the planting, growing, harvesting and processing of biologicals (corn, wheat, barley(yum!)) against their ethanol yield, it seems only fair to charge the digging, blasting, hauling, elevating, crushing, processing, and environmental/human resource costs against coal.
I'm kinda picky that way.

That's not what I'm getting at, though. The article doesn't make any sense when they say
Right now, ethanol is primarily made out of corn or sugarcane. It's expensive and time-consuming to make, a problem. A gallon of ethanol derived from plant matter also only has around two-thirds of the energy content of a gallon of gas. A gallon of ethanol derived from coal-created synthetic gases could provide more energy.

"You could avoid an energy penalty" with coal ethanol, Spivey said.

Either it's complete nonsense, as the ethanol has the same energy in either case; or it's a poorly worded way of saying "We'll produce energy with ethanol from coal, unlike with ethanol from corn". First, that would be incorrect, as growing ethanol from corn does produce energy. Second, they're counting the energy of what goes into producing corn ethanol, but they aren't counting the energy that goes into coal ethanol: namely, coal.

For every MJ of oil that is converted into corn, you get something like 1.3 MJ of ethanol. For every MJ of coal converted, you get something like 0.5 MJ of ethanol (something less than one, anyway). Claiming coal "could provide more energy" or "You could avoid an energy penalty" is only true if you ignore the MJ of coal that goes into it. As burning coal is unpopular, they can claim "since we couldn't just burn the coal, there's no opportunity cost to using it, so we don't have to account for that energy".

If I believed CO2 sequestration will work, it would actually be a reasonable argument.

[Dilb]

But if its not about CO2 emissions, why not just find a way to convert coal to gasoline? It basically needs more H2, but you can get there.

See mhaze's post.

[joobz]

errr...

Fuel lifecycle analyses are complicated. An intellectually honest analysis/comparison will try to compare like with like. So, you have to define what you mean by "well-to-wheels," in either process. Part of this is determining your basis of comparison. The most strictly honest is KJ of process energy per KJ of energy delivered at the pump. A useful measure is KJ of process energy per Km driven, because you may get some benefit like enhanced combustion.

When looking at energy efficiency, it can be found that conventional oil and gas gives about 0.3 KJ process/KJ pump, whereas ethanol from grains (avg. wheat and corn) might be about 0.75 KJ process/KJ pump. Both processes are energy efficient (despite the outright lies you might have heard about ethanol), but clearly, conventional sources are 'cheaper.'

If a cheap, clean coal conversion can be found, then you'd be laughing! This is not necessarily woo. EtOH is made from C, H and O (empirical C2H6O), all of which are found in CO and H2.

ETA: phildonnia, CO2 emissions are a separate (if not totally unrelated) issue from energy economics. It just depends what your policy makers (or voting public) are prioritizing...
Very nice summary, Jimbo07. I fully agree, and would like to add that you need to also account for other product formation during processes. If, for instance, one method has "waste streams" that can actually be sold for other uses, this process has a much higher usable yield that wouldn't be accounted for in the kJ comparison. This isn't just better in terms of economics for the company, but is the industrial analog to using the whole buffalo and not just the meat.

[rwguinn]

That's not what I'm getting at, though. The article doesn't make any sense when they say


Either it's complete nonsense, as the ethanol has the same energy in either case; or it's a poorly worded way of saying "We'll produce energy with ethanol from coal, unlike with ethanol from corn". First, that would be incorrect, as growing ethanol from corn does produce energy. Second, they're counting the energy of what goes into producing corn ethanol, but they aren't counting the energy that goes into coal ethanol: namely, coal.
Yeah-- I ignored that stuff since it is obviously complete hogwash. Like a pound of lead is heavier than a pound of feathers.

For every MJ of oil that is converted into corn, you get something like 1.3 MJ of ethanol. For every MJ of coal converted, you get something like 0.5 MJ of ethanol (something less than one, anyway). Claiming coal "could provide more energy" or "You could avoid an energy penalty" is only true if you ignore the MJ of coal that goes into it. As burning coal is unpopular, they can claim "since we couldn't just burn the coal, there's no opportunity cost to using it, so we don't have to account for that energy".

If I believed CO2 sequestration will work, it would actually be a reasonable argument.There is something terribly wrong and inconsistent in that argument, but I'm not sure how to pinpoint it. It doesn't pass the "smell test"---Like they would contine to mine it when they cannot use it...

[neutrino_cannon]

So, basically this is a different variant of coal gasification, which was used on a large scale by Nazi Germany in WWII, correct?

It's hardly news, although the desired end product had been diesel in the past.

And, if I reach into the dark recesses of memory, the process is rarely cost-efficient in a free market with wide scale access to petroleum.

[MRC_Hans]

It may not be about CO2 emissions, but unfortunately (for them) the idea of using ethanol in the first place IS about CO2 emissions. There are very few sensible reasons for using ethanol for fuel, except to reduce CO2 emissions. The only other one really being lack of adequate access to fossil fuels (like in the case of Brazil), but if you have coal ....

Of course, coal is not very practical for use in the transportation sector (although Benz's first internal combustion engine burned coal dust), but it can be converted to gasoline (Germany did that during WW2).

In a scenario where we are running out of oil, converting coal to liquid fuels could buy us some time, of course.

Hans

[Dilb]

It may not be about CO2 emissions, but unfortunately (for them) the idea of using ethanol in the first place IS about CO2 emissions. There are very few sensible reasons for using ethanol for fuel, except to reduce CO2 emissions. The only other one really being lack of adequate access to fossil fuels (like in the case of Brazil), but if you have coal ....

Ethanol as fuel has some pretty good properties. Compared to gasoline it has a higher octane rating, it's cleaner burning, it's less toxic (although maybe I shouldn't count this, as it would almost certainly be methylated), and it's not carcinogenic (and maybe not this either, if they dehydrate ethanol with benzene). It even works in existing engines with a few modifications. None of these justify the expense of producing ethanol, but they're still nice properties.

[joobz]

Ethanol as fuel has some pretty good properties. Compared to gasoline it has a higher octane rating, it's cleaner burning, it's less toxic (although maybe I shouldn't count this, as it would almost certainly be methylated), and it's not carcinogenic (and maybe not this either, if they dehydrate ethanol with benzene). It even works in existing engines with a few modifications. None of these justify the expense of producing ethanol, but they're still nice properties.
yeah, but it's highly solvent like on seals. It's fully miscible with water (and can absorb water from the atmosphere) which could cause problems in systems that aren't well sealed. and cleaner burning isn't really an issue since cars have a catcon. Also, it being such a short chain and already partially oxidized, it just doesn't have the same amount of energy as gasoline.


My money is for Deisel (in particular biodesiel). It is much safer to use, has a much higher energy denisty, modern engines are extremely clean, and doesn't require as much processessing. The only concern is the sulfur content, but this has already been decreased.

[Hindmost]

yeah, but it's highly solvent like on seals. It's fully miscible with water (and can absorb water from the atmosphere) which could cause problems in systems that aren't well sealed. and cleaner burning isn't really an issue since cars have a catcon. Also, it being such a short chain and already partially oxidized, it just doesn't have the same amount of energy as gasoline.

The water absorbtion problem will mean that ethanol can't be pumped through existing pipe systems and will have to be trucked around...certainly a problem when diesel trucks will be required for transport.

My money is for Deisel (in particular biodesiel). It is much safer to use, has a much higher energy denisty, modern engines are extremely clean, and doesn't require as much processessing. The only concern is the sulfur content, but this has already been decreased.

Biodiesel is fine, however, the amount of oil produced that can be used for biodiesel is limited. It does give the same type of problems with corn and ethanol as it is difficult to produce in significant quantities. The US uses about 50-60 billion gallons of diesel for transportation each year. Biodiesel can probably contribute about 5 to 10%. I would venture to say other countries will have similar issues.

glenn