The case for a methanol-based economy


by Jollo
Tags: density, economy, energy, infrastructure, methanol
Jollo
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#1
Jan30-12, 11:18 AM
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Note to mods: this is my first post, unsure about the best forum for this query. Please feel free to move if necessary. Thanks.

I have this wild notion that one possible way to “quickly” replace fossil fuels is methanol. Methanol is the simplest alcohol (CH3OH), liquid and stable at room temperature, and can be burned in existing internal combustion engines with a few modifications. It can also be transported and distributed with the existing transport infrastructure used for petroleum derivatives (pipelines, supertankers... down to the local gas station). So, unlike with hydrogen, you can switch to a methanol-based economy with moderate infrastructure changes.

Methanol can be produced out of CO2, water and sunlight: basically, you electrolyze water using power generated by a solar panel (2 H2O → O2 + 2 H2), discard O2 in the atmosphere, put H2 in a reactor with CO2 (needs a cheap metallic catalyzer, plus some heat and pressure also powered by the solar panel) et voilà: CO2 + 3 H2 → CH3OH + H2O. Recycle H2O into the process (thus lowering H2O demand by 33%) and collect methanol, ready for transportation and usage (no further refinement is necessary). The problem is: where do you take CO2 from? In today’s industrial base, from petroleum processing (driving the false impression that methanol itself is a petroleum derivative). In principle, it could also be captured directly out of the atmosphere.

Burning methanol and air (e.g. in an internal combustion engine) will create CO2 (2 CH3OH + 3 O2 → 2 CO2 + 4 H2O), but if methanol is produced capturing CO2 from the atmosphere the production-combustion cycle is carbon-neutral. Also, combustion leaves no nasty pollutant by-products (aerosols, NOx, aromatic hydrocarbons, etc..).

Methanol does has a few problems to be worked around: it is corrosive for aluminum and a few other metals, so a few components along the whole cycle might have to be re-designed accordingly. Methanol’s specific energy (circa 20 MJ/kg) is less than half than gasoline's (up to 47 MJ/kg), but packing a little less punch in your car engine will not kill anyone (in your aircraft engine that might be a little more worrisome... but I'm confident ways around can be found). It is toxic if ingested, but not more than gasoline. On the other hand, unlike gasoline and petroleum, it is quickly bio-degradable (7 days half-life in water).

The problem is that typical atmospheric CO2 concentrations (around 390 ppm by volume) would make for very low production yields, but efficiency issues and a “weak” energy source (such as a solar panel) would cap process yields to very low values anyway.

So this is how I imagine this could work on a large scale: litter a desert with small, autonomous sunlight-powered processors with a water tank (initially full), a methanol tank (initially empty) and lots of time and sunshine to perform the conversion. A fleet of robotic, automated collectors could do the “milk runs”, collecting methanol and refilling water tanks, visiting every individual processor perhaps every few months (and replacing broken down or ageing processors for refurbishment while they’re on the spot). Or imagine an ocean littered by small, autonomous floating processors (no need for the water tank, but you’d have to figure out displacement) and robotic collector ships doing the rounds.

Now for a few disclaimers:
  • I am *not* talking here about energy *generation*, I am talking about energy *storage* and *transport*. I’ll say that again: I am fully aware that the energy balance of the process described above is *negative*. Please don’t go off charging about ignoring the first law of thermodynamics: there’s loads I don’t know, but please believe I’ve got Physics 101 down on pat (I hope).
  • I once read (Heinlein, so we’re fully into SF!) that energy is literally “raining soup” (in radiation, wind, temperature gradients, etc.), but never in the right place, time and density to be useful. I happen to agree: what I am looking for here is a method to *store* energy in a medium with:
    1. decent specific energy
    2. decent economics
    3. easy transportation and storage
    4. easy energy retrieval (e.g. combustion or fuel cells) and
    5. applicable to low yield energy transformation processes (something like days or months to gather energy and seconds to deliver it where and when needed)
  • We already have such a medium, and it works great: it’s called gasoline (or variations thereof, from mazut to JP4); alas we only know how to produce it economically from fossil petroleum, and lots of problems ensue
  • Hydrogen would be a great idea (and has about double the specific energy of gasoline), but fails miserably on the #2 and #3 requirements: it’s the most volatile gas in the universe, and it’s horribly expensive to store and transport safely. A couple of orders of magnitude too expensive.
  • Chemical batteries are very efficient, but have a very low specific energy (less than 1MJ/kg for the most expensive types). At least an order of magnitude too low for most applications.

Now for a little amplification: methanol is liquid and stable at room temperature, much of the existing petroleum-based transport infrastructure could be adapteded with moderate change, it has a decent specific energy and can be produced and burned in a carbon-neutral cycle. It looks like a promising candidate on all counts.

I am therefore asking some expert opinions about this scenario, especially about the economics, and about possible alternatives that would fit the bill. Thanks in advance.

Jollo
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Andre
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#2
Jan30-12, 03:42 PM
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well feasibility of producing energy doesn't really look like earth science to me.

The things you are proposing appear sound qualitatively but how about quantitatively? This would require a standard feasibility study, I can't link to an example of such a study and the things to consider because that would get a commercial bias, but we can google it.

Then you'd have to compare with other solutions, for instance: would nuclear produced methanol be more efficient?

And then, no doubt policy and politics take over.
Bobbywhy
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Jan30-12, 05:56 PM
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Jollo, Welcome to Physics Forums!

Brasil has for years used methonal-powered cars, but only a small percentage of the total. I have lived in Brasil more than ten years and my observation is that ethanol only been moderately successful and poorly received by the population.

See: http://www.economist.com/node/21542431

A comprehensive essay on ethanol production, use, and economic information is available here: http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil

Jollo
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Jan31-12, 11:11 AM
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The case for a methanol-based economy


Quote Quote by Bobbywhy View Post
Jollo, Welcome to Physics Forums!
Thanks!

Quote Quote by Bobbywhy View Post
Brasil has for years used methonal-powered cars, but only a small percentage of the total. I have lived in Brasil more than ten years and my observation is that ethanol only been moderately successful and poorly received by the population.

See: http://www.economist.com/node/21542431

A comprehensive essay on ethanol production, use, and economic information is available here: http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil
Very interesting links, I'll study them in depth. Well, you're talking about ethanol (CH3-CH2-OH) and I was talking about methanol (CH3-OH), but the parallel is anyway useful, especially regarding direct use as an automotive fuel. From your direct experience, could you summarize in a few words why was it "poorly recieved" by end users?

However, the economic foundations are very different: ethanol is distilled from sugarcane or corn fermentation, so the raw materials comes with both production and opportunity costs (the farmer's profit and what else could he cutivate on the same land), not to mention some infamous fiscal benefits...

In methanol's case, sunshine is free, and whatever amount not used is forever lost. The land area used to collect sunshine draws both capital absorption and opportunity costs, but if you use a desertic area those tend to be negligible. Atmospheric CO2 don't cost anything. You could argue that water delivered at the processor is not free, but that's transport, not raw materials.

That's the catch: if raw materials are "for free", and you have only processing and trasportation costs, the perspective changes quite a bit. For instance, efficiency becomes a kind of second tier issue: if the process is economically viable, who cares if it doesn't make an efficient use of a free resource?

As for powering a methanol processor with nuclear electric power... well, if you've got megawatts of electric power 24/7, ready to be sold through an existing grid, why would you bother to convert it into anything else?

Thanks for the inputs, keep it coming please.

Cheers
Ryan_m_b
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Jan31-12, 11:20 AM
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Welcome to the forum

Turning solar energy into storable, carbon-neutral fuel is something I find fascinating although outside my field. We briefly discussed it recently with regard to artificial photosynthesis http://physicsforums.com/showthread.php?t=42564&page=49 (post 780 and 781).
Bobbywhy
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Jan31-12, 11:58 AM
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Oops! I confused methonal with ethonal! Excuse me, it was just a "senior moment"!

Methanol does appear promising. Has our own Department of Energy studied it's potential value? What Universities and what private companies are studying/developing methanol?

As for ethanol use in Brasil, one problem ethanol-powered car drivers have is poor performance such as less acceleration than with gasoline. Another drawback is that only a select few gas stations carry it, so ethanol powered cars can't travel far from large cities. One other issue which works against ethanol is that to grow sugarcane (the major source) huge areas of farm land are necessary. This subtracts from available land for food production, which, I think, keeps food prices high. The growers have to apply massive amounts of fertilizers year after year owing to soil depletion from single crop cultivation, and this causes environmental pollution. Lastly, greedy growers/producers use "slave labor" who receive very low pay to cut and collect sugarcane. I have personally seen many of these operations where families live in primitive living and working conditions. Add to that the continual indebetedness to the "company" amounts to a social malaise.
AthensNY12015
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Jan31-12, 03:04 PM
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Jollo asked: "As for powering a methanol processor with nuclear electric power... well, if you've got megawatts of electric power 24/7, ready to be sold through an existing grid, why would you bother to convert it into anything else?"

It seems that there are certain cases where nuclear power can be used to foster carbon sources of energy while avoiding the political hazards of nuclear develpment. That is in remote areas ...

The power grid isn't very efficient, and placing nuke plants a far distance from population centers doesn't make much sense if one is concerned about the efficiency of power transmission lines over long distances. But, placing nuke plants too close to polulation centers is fraught with political risks. So, using nuke generated electricity to create a safer and more easily transported power source could be economically feasible.

For example, what if Canada decided to use secondary coolant to help extract oil from the tar sands of the NWT? No protests over nules, because the plant would be remotely situated, and the environmental and public safety concerns would be relatively few. Then use all that energy and the ample water available in NWT to produce both methane and oil? Then ship the carbon-based fuels by pipeline or other means. Seems that after the initial investment, the transportation of fuel is less inefficient than the transportation of electricity, thereby making remote siting of nuke power plants useful when they can be used to create transportable carbon-based fuels.

IMHO.
skeptic2
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#8
Jan31-12, 07:09 PM
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Although methanol is widely used in racing, it is also toxic by inhalation, ingestion and absorption through the skin. If it were used by the generally uneducated public, how many cases of blindness and death would it cause?

A friend from Russia tells me that when he lived there, it was absolutely banned because alcoholism being such a problem, people would drink it when they couldn't get ethanol.


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