Coal — The Other Alt Fuel

This Wired piece is really a round-up about Coal: The Other Alt Fuel. One of the main stories is about an initiative to convert low-grade coal to other uses — like diesel fuel and so forth, but of course that nasty issue of carbon production comes up again.

Comments

Hg, S, Fe, NOx & CO

[grolaw]

To name a few of the really, really serious biproducts of Coal usage. Hg precipitates out from exhaust at an alarming rate (*those states with coal-fired power plants all have massive Hg and CH2-Hg contamination: see, http://www.dnr.mo.gov/pubs/pub2100.pdf/ and, http://www.moenviron.org/airqualitymercury.asp/ for one central US state's Hg warnings). Sulphur fom coal burning is the primary source of H2SO4 in acid rain that has decimated the lakes in the Northeast US and etched limestone (Cleopatra's Needle http://members.aol.com/Sokamoto31/ny.htm/ has been in NYC since 1881 and the two sides facing the prevailing wind have been etched free of inscription (perfect on all four sides when it was put it into place) due to acid rain) building materials. Nitrates (NOx) are the secondary sources of acid (HNO3 Nitric Acid being the most common) and a product of incomplete combustion of coal. About 75% of the coal-fired power plants scrub NOx out of the exhaust - but there appear to be no small-scale scrubbers consistent with vehicle use.

Releasing more Carbon from the carbon sink is just one more addition to the ever-increasing load of greenhouse gasses on the planet.

Iron - in its various forms will "poison" any catalytic converter small enough to fit on a vehicle.

The cost of scrubbing or converting Coal into a cleaner-burning fuel is problematic and the energy used to scrub may well exceed the energy realized from the converted coal.

Re:Hg, S, Fe, NOx & CO

[LWATCDR]

Yes but.
Coal is a hydrocarbon. It is possible to extract the hydrogen from it and use it as a fuel just as you can extract hydrogen from natural gas.
You can convert it into coal gas and filter that to remove the sulfur and mercury.
The big question is will it be practical?

You have one really big technical error.
"About 75% of the coal-fired power plants scrub NOx out of the exhaust - but there appear to be no small-scale scrubbers consistent with vehicle use."

NOx doesn't come from from coal. If you burn any fuel in at a high enough temperature you get NOx. Actually you can get NOx even when you burn pure hydrogen.
NOx is made when atmosphere nitrogen is held at too high a temperature for too long. One of the ways cars used to try and keep the NOx low was to run a little rich and then use air injection or a latter a simple catalyst to the burn off the the extra hydrocarbons at a lower temperature.
That is why early US emission controlled cars had such bad gas millage and performance. Now they use a 3-way catalyst, computer controls, and advanced combustion chambers to handle it. Gas turbines try and get the hot gases out of the combustion chamber as fast as possible so that the NOx doesn't have time to form. It is a very interesting problem. If you could just replace the nitrogen with helium it would make everything so much simpler.
A car using gasoline or diesel made from coal shouldn't have any worse NOx emissions than using oil based fuel.
Just like with the solar power stations there are problems but they should be looked at honestly. Even if it is a problematical fuel it could still be used as a feed stock for plastic production.

Re:The issue is not the pollution

[1u3hr]

Nuclear power is contentious, difficult, and actually not in infinite supply. The world would consume all the nuclear power in a couple of decades; and there isn't any easy way to make its energy available for transportation.

I'm not at all a nuke booster, but this isn't true. If you use breeder reactors you can convert non-fissile U238 to Plutonium, which multiplies your available fuel (U235) by a factor of hundreds. And it's not hard to transport electricity, it's just how efficient it is. Aside from copper cables, there's the possibility of cracking water to make hydrogen. Further out, maybe superconducting cables. Also you can make portable reactors on barges and move them to where they're needed.

Lots of safety and political issues, but the pure science isn't a problem.

Fisher Tropsch

[marcovje]

Isn't the Fisher-Trops 65 years old already? Germans used it in WWII for aux fuel, and so did South Africa during the boycott (SASOL).

The Club of Rome also named this as possibility in 1980 (I never read the first report, only the revised one)

Re:Fisher Tropsch

[drnlm]

SASOL is still going strong here in South Africa. We have lots of coal, and it's quite expensive to import oil, so the whole process is still economically viable without the boycott. As a result, though, Sasolburg is one of the more polluted cities in the country (see amongst others the groundwork's 2002 annual report on this site.)

Nothing new.

[Anonymous Coward]

Sounds suspiciously like Fischer-Tropsch synthesis, which - I believe - has been used extensively for nearly a century. Anyway, I'd hardly call coal an "alternative" fuel. Coal fuels cooking fires, trains, and power plants. Coal is the primary source of Petrolium and Diesol in certain areas, and has been fuelling millions of cars for decades. By comparison, gasoline is an "alternative fuel".

Re:The issue is not the pollution

[Mr. Slippery]

If you use breeder reactors you can convert non-fissile U238 to Plutonium, which multiplies your available fuel (U235) by a factor of hundreds.

The security implications of plutonium breeding make it unsuitable as a solution. And if you imagine fission scaling up to be the primary energy source, even with breeder reactors you still run out of uranium within decades, perhaps a century. Reactor safety is a huge issue (no, pebble bed reators are not as safe as fission fans tell you). And the waste problem remain unsolved.

Thorium spallation in an sub-critical accelerator driven system is a possibility, with much greater safety and availabilty, but doesn't yet exist in practical form. Same for fusion.

Photovoltatics, renewables, and efficiency improvements exist in practical form now.

Just point out

[Colin Smith]

That none of our power stations (including nuclear, fission and fusion) are going to get much above 40% efficient until we stop treating waste heat as waste. Overall efficiency can be doubled to the 80%-90% region by selling the heat for industrial processes, domestic water, space heating and to power chillers which can distribute cold water in hot regions.

Most of our electricity is used to create or move heat from one place to another. It's highly ironic that power stations produce more energy as heat than they do as electricity. With District Heating and District Cooling it's possible to distribute heat and cold such that the requirement for space heating and air conditioning is massively reduced.

This isn't going to happen any time soon, economically it simply isn't worth while, it's much cheaper to dig up coal or pipe oil or gas. That could change with the flick of a pen though. At the moment every working individual pays 30%-40% of their income as taxation, get rid of it and add the equivalent level of taxation to fuel sources, in particular the non green methods of generation. The utilities will then squeeze every Watt out of the fuel, and customers will make sure they don't waste any energy either. As a side effect, people will become much cheaper to employ.