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Coal to Liquid Fuels (merged)

Discussions of conventional and alternative energy production technologies.

Coal to Liquid Fuels (merged)

Unread postby Viper_gst1 » Sat 05 Jun 2004, 09:19:39

Liquid Coal

I posted this as a comment to an article, but I figured this would also be a good discussion topic.

Um, OK, so if coal converts at a 5 to 1 to crude, and assuming that it costs you nothing to do the conversion(yeah, right...), and coal is selling for $58 per ton. Lets see, that would come out to about $40 per barrel of crude from coal

Yep, this totaly solves the cheap oil problem. /sarcasm
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Unread postby pepper2000 » Sat 05 Jun 2004, 13:18:58

Not to mention the pollution. It won't be long before we need to wear gas masks to go outside.
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Unread postby OilBurner » Mon 07 Jun 2004, 10:03:41

Not forgetting the fact that if we moved from using oil to oil derived from coal then the demand on coal would shoot up, meaning the price of coal would also shoot up.

Hmm. Small problem with replacing gas and oil with coal...before you even start on the environmental implications.
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Unread postby EnviroEngr » Mon 07 Jun 2004, 11:20:58

Regardless how you fiddle with the carbon chains or what energy it takes to rearrange the sigma, pi, sp3, sp2 hybrid and other covalent bonds, if you're thinking of US Coal stocks, look at this: The Peak in U.S. Coal Production
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Unread postby OilBurner » Mon 07 Jun 2004, 11:30:41

That's news to me - I thought we had more coal than we knew what to do with, 200 years supply or so.
But then, I used to buy the theories about having oil for 200 years etc etc.

How long before someone comes along and argues that coal renews from the Earth's mantle too!! :lol:

Perhaps Peak Oil would be more accurate (and the consequences more far reaching) if it was expressed as Peak Energy?
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Coal

Unread postby Doctor Doom » Tue 08 Jun 2004, 11:40:26

We really do have 200 years of coal production. Of course this will follow its own Hubbert curve but there is quite a bit of it around.

http://www.wci-coal.com/uploads/CoalFacts03.pdf

25% of the world's coal reserves are in the US. Of course, we are using it for 50% of our electricity needs (40% world-wide), so if we ramp that up to 100%, the r/p ratio would drop from 200 years to 100 years. Coal accounts for 25% of total world energy needs right now, so if we called on it to meet 100% of all needs the r/p ratio would be 50 years.

Of course none of those extreme cases is likely. We can get 10% of electricity needs from renewables (hydro alone is close to 7%) and another 20% or more from nukes (France gets 78% of their electricity needs from nukes, Japan gets 50%). I figure we'll start ramping up coal to meet electricity needs as the natural gas starts to run out and the folly of building all these gas-fired plants starts to become apparent. I figure coal is meeting 70% of US electricity needs in the endgame.

There will also be some increased use of coal to make synfuels, as a substitute for lost oil production. That plus a LOT of conservation will be the story in transportation. 2/3 of the oil used in the US is for our cars - that will have to be cut in half, which is possible but will be very disruptive. Jet travel will be a luxury for the very wealthy; people will go back to using trains for long trips. All of that will buy maybe 20 years to manage our way down from the peak.

During that 20 years, we will have to build wind farms and PV collectors like crazy. Yes they take energy to make, but they are currently energy positive and that's what counts. PV with current technology pays the energy back in 2 years, and there are new technologies in the works that could double the output. If a PV panel lasts 10 years, that's a 5:1 energy payback, 10:1 if the new technologies pan out, and even longer if the 10 year lifespan is extended. Wind generators pay back input energy in 6 months.

The pessimistic scenarios assume we won't have the oil to build these things, but if you look at it solely from an energy in-out perspective, you could build such things and then use the energy dividend to build more, then yet more, etc. You use the energy you get from them to displace fossil use and divert the fossils thus saved to building more of them, or you use the energy to get from them to produce substitute fuels to build more. In theory you'll be limited only by the availability of suitable sites and the raw materials needed to construct them.

Overall, I think coal is going to be very important to managing the post-peak decline. Our coal reserves will buy us maybe a generation to make a transition, which we had better not fritter away!
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Unread postby OilBurner » Wed 09 Jun 2004, 05:35:09

Coal is clearly important. Our problem in the short term is that in the west, coal use is actually being cut down. Good for the environment but terribly risky.
For instance, in the UK we have a lot of coal burning power stations, they are all old and pollute like there's no tomorrow. In order for these to remain online, they are required by law to have particulate filters fitted.
The energy companies (of which I have insider information on one of Europes biggest) are planning to shut these power stations down (or at least mothball them) rather than fit expensive filters.
The replacement power generation will be partially "renewables" but mostly natural gas.

I don't think this situation is unique.

Therefore, to move towards coal to retain sufficent energy inputs to enable us to produce PV, Wind and Nuclear is going to require some years of planning and investment. Those years may be a luxury we cannot afford, especially if gas production hits a cliff.

I also wonder where the practical limit of coal extraction is. Each coal mine, whether they are underground or open cast must have a physical limit on how much coal can be removed at any one time. I doubt it's well understood what the limit may be or whether it's capable of dealing with a increase in demand with perhaps only months or a couple of years to adjust.
These increases in demand could be huge. One lb of coal = 16,000,000 joules and one lb of oil = 24,000,000 joules. Therefore, before even taking into account the energy required to turn coal into oil, we already need 50% more coal than oil to fulfill the same energy purpose.
That means, one barrel of oil contains about 254 lbs of oil. To replace one barrel of oil with coal requires 381 lbs of coal. So, to exchange a mere 10 million barrels a day of oil, will require 1,905,000 tons of coal - plus the energy to do the conversion process. That's 696 million tons per year or 14% of current coal production of around 5000 million tons per year. Not impossible, but very challenging - and that's to replace 12.5% of current oil demand. In this scenerio we'd need all the renewables we could get to power the conversion process too.
If we start talking about 20% or 30% of current oil consumption then we'd better start producing some more fuel efficent cars and fast!! A 30% drop in oil would equal around a 33% increase in coal production plus large amounts of renewables or nuclear power to balance the energy equation.

According to this report ( http://www.planetark.org/dailynewsstory ... /story.htm ) China is turning 13,000 tons of coal into 50,000 barrels of oil. 13,000 tons = 26,000,000 lbs. 50,000 barrels = 12,700,000 lbs. That's indicating that the process is actually so inefficent that they're only turning half the energy potential of the coal into oil. Therefore, the more accurate figures may be - 10 millon barrels of oil requires more like 920 million tons of coal or 18.4% of current coal production to replace 12.5% of current oil production. Whoops - looks like we'd better start building a lot of windmills, mini-hydros, PVs and nuclear plants and we'd better start on it fast!!

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Unread postby OilBurner » Wed 09 Jun 2004, 05:52:25

Silly me - I forgot to turn the conveted coal oil into it's energy equivilent.
26,000,000 lbs of coal = 416,000,000 million joules
12,700,000 lbs of oil = 304,800,000 million joules

Which means they are claiming around a 73% efficency of turning coal into oil in terms of the energy potentional from the original coal and what remains in the new oil.

So for 1 lbs of coal they'll get 0.73 lbs of oil.

So 500 million tons of coal produces 365 million tons of oil or 2874 million barrels of oil.
To replace 10 million barrels of oil per day will require 1.74 million tons of coal per day or 636 million tons per year - or 12.72% of coal production to cover 12.5% of oil production.

Still not very good and brings me back to me original point - just how much more coal can be produced at any one time?

Hopefully my maths are right now!! :)
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Unread postby OilBurner » Wed 09 Jun 2004, 06:19:24

Another mistake - damn that submit button!! :lol:

It should have been:
1.5 lbs of coal = energy equivilent of 1lb of oil.

Therefore, with a 73% efficency rate of conversion of coal to oil, 1.5 lbs of coal becomes 0.73 lbs of oil.
Or 1 lbs of coal = 0.488 lbs of oil.
To produce 1 barrel of oil (254 lbs in energy terms) needs around 520 lbs of coal.
520 lbs of coal = 0.26 tons.
To replace 10 million barrels of oil = 10,000,000 x 520 = 5,200,000,000 lbs of coal = 2.6 million tons per day or around 950 million tons per year.
That brings me back to my original silly numbers equation of roughly 20% of current coal production to replace 12.5% of current oil production. Not a very reassuring ratio.
If we are heading towards a gas cliff as well as an oil peak then it's hard to see how nuclear and renewables will help plug the gap, because I doubt coal will be able to help that much - especially since energy demand is increasing.

Phew!!! Maths was never my strong point...
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Maths

Unread postby EnviroEngr » Wed 09 Jun 2004, 10:17:38

Nice job. I'll check some of this when I get a chance. My Physics book has a good chapter in Dynamics on Work and Energy. All the differential equations are final integrated into nice little algebraic equations with boundary value conditions that would work for your scenario.

My little black Ref book says a US Barrel (oil) is 42 US Gallons. Is this assumption correct? Is it the one you used?
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Unread postby OilBurner » Wed 09 Jun 2004, 10:50:15

Thanks! Shame I didn't get it 100% on the first post.. :oops:

These are my assumptions / conversions in full:

1 barrel of oil = 42 U.S. gallons
1 ton = 2000 lbs
1 lb coal = 16,000 Kjoules
1 lb oil = 24,000 Kjoules (oil expressed in weight, not volume as is the norm)
1 barrel of oil = approx 6,098,400 Kjoules, therefore 1 barrel = 254.1 lbs of oil
current daily oil production = 80 million barrels
current annual coal production = 5000 million tons (very approx)

You can actually just express the whole thing in Kjoules without converting back and forth and the end result should be the same, i.e. coal has less potential energy than oil and converting that coal to oil wastes some of that energy because the process can never be 100% efficent. In fact, I'm surprised they get 73%, that's pretty good going if it's true and doesn't require energy input from elsewhere.
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King Coal

Unread postby Doctor Doom » Wed 09 Jun 2004, 16:00:51

73% is better than I thought it would be. In the case of the US, we could probably do better than China. Consider this: some portion of our electricity comes from natural gas. We could replace that with coal plants at 100% efficiency. It's also probably possible to do better than 73% with "direct use" of coal for heat in processes such as fertilizer production. In fact in Australia they use more gas than oil for that purpose. My point is, before taking the 73% hit, we would probably start substituting coal wherever we could to directly use the energy, and it would relieve pressure on gas and oil supplies - for a while.
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Unread postby Guest » Wed 09 Jun 2004, 20:36:05

OilBurner wrote:Perhaps Peak Oil would be more accurate (and the consequences more far reaching) if it was expressed as Peak Energy?


There will always be plenty of energy.

When the world used whale blubber for everything, I guess they had a Peak Blubber crisis. If you just defined energy as whale blubber, then I guess there really is a crisis.

Wind energy is almost competitive with natural gas, nuclear and coal. It is possible to run cars off of electricity from the power grid.

The transition will be painful and take a few years, but there are numerous sources of energy for the world to continue beyond oil.
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Unread postby OilBurner » Thu 10 Jun 2004, 04:39:52

Anonymous wrote:Wind energy is almost competitive with natural gas, nuclear and coal. It is possible to run cars off of electricity from the power grid.


Wind energy as competitive as gas, coal and nuclear? In cost AND energy capacity Really???

A wind turbine in a good location with good weather conditions gets 60,000 KWh per year ( http://home.earthlink.net/~fradella/green.htm ) compared to total KWh used by the USA per annum of 3,848 billion KWh ( http://www.eia.doe.gov/emeu/cabs/usa.html ).

You can argue all you like that wind power may or may not be cheaper than coal or gas or nuclear etc. However, the fact remains, to replace 20% of the US energy demand with wind turbines requires 12.8 million modern wind turbines situated in areas where average windspeeds of 20mph can be obtained.
In 2003, current wind turbine capacity was 6374 MW of a total generating capacity of 905 GW (2002 figure) or 905,000 MW. That makes wind power equal 0.7% of all US generating capacity. It's got a long way to go to be competitive, a hell of a long way. Forget cost, it's all about meeting demand. The US has around 500,000 turbines (based on energy output - actual figure may by higher depending on KW output of older designs) and needs to increase that figure by 2560% just to meet 20% of current demand. To meet a more environmentally sound target of say 50%, we're talking of 32 million wind turbines. :lol:

I very much doubt there's even enough ideal sites for that many turbines, never mind a hope in hell of overcoming the NIMBY problem to install them all.
I wish it really were as simple as replacing 80% of power generation with wind, solar and hydro with a 20% stability factor from nuclear - but we are a very long way from being able to do that.

Also, you mention running cars off the electricity grid, have you any idea how much more generation capacity would have to be added to cover at least 10 million barrels a day of oil used for transport in the US?
1 million barrels = 73GW ( http://physics.syr.edu/courses/modules/ ... ables.html ), so 10 million (current US daily oil consumption for transport) = 730 GW or 80% of exisiting generation capacity.
That simply isn't going to happen.

Let's face it, moving towards renewables will take a massive drop in energy consumption to make any appreciable difference. The economic and social upheaval will be truly enourmous.
We're not talking about a minor adjustment here, we're talking about the difference between industry having power and not, between driving to work or not getting there at all. Obviously, we aren't going to voluntarily do that to ourselves, hence why renewables remain a small percentage of overall energy use.
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Cost/Efficiency/Sources

Unread postby Guest LC » Fri 02 Jul 2004, 19:24:56

Wind on a COST basis is competitive. There isn't much of it produced because costs have recently fallen and gas prices have recently tripled. But according to the DOE it's 5 c/ kwh. A large windmill is 1MW and has a capacity (in well sited places ) of 30-40%. And you don't need 20mpg {mph??; EE} wind. The DOE thinks the cost in 12mpg wind will be 3c/kwh by 2010.

A 1MW turbine that is well sited generates 3M kwh of electricity per year and costs about 3/4 of a million dollars. At 10% that .75M is $75,000. So $75,000/3m is 2.5 c/hour. Plus maintenance, plus hooking up the power lines, etc.


YOu could put windmills in the barren windswept Mid-West at 1000 / sq mile. The plains have about 2 million square miles. So there's ample room. Not all great wind sites, but ample room. The problem is shipping it to Chicago/St. Louis/ etc. There aren't any transmission lines near there. But they could be built.

The other problem is intermittency, but nuclear could work together with wind to balance this. When the wind isn't blowing use nuclear to generate electricity, and when it is, use nuclear to generate hydrogen. Add the hydrogen to a hydrogen poor hydrocarbon like coal and make the coal to liiquids process more efficient. Or ship the hydrogen to the fertilizer industry where they currently use natural gas as a feedstock. This would replace natural gas usage.

Good question about how many nuke plants we'd need. Right now we have 100,000 MW and they generate 20% of our power. Coal generates 50%. So we'd need to triple it to replace coal at least.

As for driving, the important thing is that gas is only 20% efficient in getting to the wheels. Electric is much more efficient.

One barrel is 42 gallons. One gallon of gas has about 35kwh of energy (thermal). So 3 billion barrels has 42 * 3e9 * 35 = 4.41 trillion kwh of thermal energy. But only 800 billion kwh of actual energy hitting the wheels from 3 billion barrels of gasoline. So how many nuke plants to generate 800 billion kwh? Right now the 100,000MW or 100 plants generates about that much. So we could replace about 80% of our driving fuels or about 3 billion barrels by doubling our current nuclear from 100gw to 200gw.

So total energy nuke energy would go up 5 fold. 300,000 more MW to replace coal and 100,000 more MW to replace electric energy in cars. Of course there would be demand peaks in rechargin cars, and it's not 100% efficient, but the point is...it's DOABLE!
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Unread postby JayHMorrison » Fri 02 Jul 2004, 20:05:21

Anonymous wrote: So we could replace about 80% of our driving fuels or about 3 billion barrels by doubling our current nuclear from 100gw to 200gw.


You don't even need to do that. Most re-charging of plug-in hybrid vehicles would occur at night. They do not turn off power plants at night. All of that capacity is available and currently is cheaper. If a large % of the population was charging their vehicle at night, that would actually be a much more efficient use of power plants assets.
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Unread postby Guest » Fri 02 Jul 2004, 20:20:13

I think you're right. But the way it works now, nuclear is run 90% of the time, ie it generates 90% of its total power capacity. Coal is run almost all the time too. Coal and nuclear with high plant costs and low fuel costs (nuclear is almost free) are perfect for "baseload".

There are also peaking plants (mostly gas) that run during the high demand periods of the day.

Basically though if you increased demand a lot at night...you'd probably still need more power plants. The ratio of nighttime demand to daytime demand is about 1:2. The spare capacity is all natural gas which a) is running out and b) is more expensive than nuclear on a 24 hour basis.
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Coal Chemistry

Unread postby EnviroEngr » Fri 02 Jul 2004, 20:39:33

Any new information about converting coal to hydrocarbon liquids?
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Unread postby Guest » Fri 02 Jul 2004, 20:54:41

I don't know if there's anything "new" about it.

The process was invented by Nazi Germany during WWII as they didn't have enough oil. So it's been around a while.

Look on the internet for "coal to oil". A ton of coal has from 15-30 GJ of energy (one kwh is 3.6M J of energy) and a barrel of oil has about 6.1 GJ of energy. The process is relatively efficient and if you add hydrogen to the mix, then you get a higher yield. But I'm no expert.
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Unread postby Barbara » Sat 03 Jul 2004, 12:11:57

The process was invented by Friedrich Bergius in 1913, and of course he was not a Nazi (the Nazi came about 1930) but he won a NOBEL PRIZE!
A friend of mine, a chemist, mentioned me this Bergius process just today talking of peak oil. To this friend, there will be no peak oil problem thanks to the Bergius process, which was abandoned because it's a bit more expensive than the cheap oil. Of course there will be a Peak Coal, but it's decades away.
He states there's no pollution problem... but this I have not checked yet.
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