http://www.washingtonpost.com/wp-dyn/content/article/2007/01/09/AR2007010901503.htmlThe Green Gripe With Obama: Liquefied Coal Is Still . . . Coal.
By Elizabeth Williamson
Washington Post Staff Writer
Wednesday, January 10, 2007; A11
Who, but who, would soil the environmental reputation of Barack Obama?
The Democratic senator from Illinois gets stellar marks from greens. Just a few months ago he was calling global warming "real," saying: "It is here. . . . We couldn't just keep burning fossil fuels and contribute to the changing atmosphere without consequence."
So why then, environmentalists ask, is Obama backing a law supporting the expanded use of coal, whose emissions are cooking the globe? It seems the answer is twofold: his interest in energy independence -- and his interest in downstate Illinois, where the senator's green tinge makes the coal industry queasy.
The coal industry praises Obama's reintroduction, with Sen. Jim Bunning (R-Ky.), of the Coal-to-Liquid Fuel Promotion Act of 2007 last week, which would provide incentives for research and plant construction. The industry says the technology, which converts coal into diesel engine fuel, would reduce America's dependence on foreign oil through a new, home-mined fuel that burns as cleanly as gasoline.
Environmentalists say focusing on coal does nothing to arrest climate change. Instead, they say, lawmakers should back cleaner alternative fuels and stricter automobile and industrial emissions standards.<snip>
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There is a peak coal date even before we factor in using coal to replace oil. A recent (2003) study by scientist Gregson Vaux, which takes those factors into account, estimates that coal could peak in the United States as early as 2032, on average. "Peak" does not mean coal will disappear, but defines the time after which no matter what efforts are expended, coal production will begin to decline in quantity and energy content. The disappearance of coal will occur much later, around the year 2267, assuming all other factors do not change.
http://www.thecanadianencyclopedia.com/index.cfm?PgNm=TCE&Params=A1SEC818434Most of the direct processes developed in the 1980s were modifications or extensions of Bergius's original concept. The coal is ground so that it can be mixed into a coal derived recycle solvent to form a coal-oil slurry feed. The slurry containing 30-50% coal is then heated to about 450°C in a hydrogen atmosphere between kPa pressure for about one hour.
A variety of catalysts are used to improve the rates of conversion to liquid products. One tonne of coal yields about one-half tonne of liquids. Processes have been developed to use coals from low rank lignites to high volatile bituminous coals. Higher-rank coals are less reactive and anthracites are essentially non-reactive.
The liquids produced have molecular structures similar to those found in aromatic compounds and need further upgrading to produce specification fuels such as gasoline and fuel oil. (All of these liquid fuel production methods release carbon dioxide (CO2) in the conversion process, far more than is released in the extraction and refinement of liquid fuel production from petroleum. If these methods were adopted to replace declining petroleum supplies carbon dioxide emissions would be greatly increased on a global scale. For future liquefaction projects, Carbon dioxide sequestration is proposed to avoid releasing it into the atmosphere. As CO2 is one of the process streams, sequestration is easier than from flue gases produced in combustion of coal with air, where CO2 is diluted by nitrogen and other gases. )
The Fischer-Tropsch (F-T) process forms the basis for indirect liquefaction of coal. The process is indirect since the coal structure is completely broken down into synthesis gas by gasification with steam and oxygen. Then the synthesis gas is reacted over an appropriate F-T catalyst to form predominantly paraffinic liquid hydrocarbons having wide molecular weight.
This method was used to produce motor fuel during WWII and South Africa has used it to produce motor fuels and petrochemical feedstocks since the 1960s. The indirect route yields a large number of byproducts and overall has a lower thermal efficiency.
(but) Among commercially mature technologies, advantage for indirect coal liquefaction over direct coal liquefaction are reported by Williams and Larson (2003). Estimates are reported for sites in China where break-even cost for coal liquefaction may be in the range between 25 to 35 USD/barrel of oil.
...The CANMET Energy Technology Centre (CETC) in Ottawa, the energy science and technology arm of Natural Resources Canada..(showed)..that the simultaneous processing or co-processing of coal and oil sand BITUMEN - a combination of direct coal liquefaction and heavy oil upgrading - could be a viable and unique alternative for Alberta, where large reserves of these resources are found in close proximity. The research has also shown that co-processing is cheaper than direct coal liquefaction and, at high enough oil prices, more cost-effective than heavy oil upgrading.
From various web locations:
It also assumes that we can get the water that CTL plants require. Neither China nor the major coal producing parts of the US are going very well, water-wise. Or that the plants use dry cooling. But the water used by the chemical reactions themselves is rather modest. In some cases, the coal bed water is sufficient. Disposal of this water is a problem in parts of the US west, due to dissolved salts. But relative to agriculture, the Industrial processes actually uses minuscule amounts of water (aside from cooling, a temporary use of water without it contamination and with close to 100% recycling – similiar to the water use as heat sink ponds at nuclear plants). But most of the loss of water is to evaporation which then is precipitated - some locally soon after evaporation, but mostly far away. There would be other negative offsets in increased coal mining related deaths each year plus respiratory illness in the general population and toxic ground water if not regulated well. There may well be a trade off decision to be made between energy production and a local Agriculture drought, especially as coal is often found in water short areas of the world. The competition to liquidfied coal is cellulosic ethanol which has had to wait while we got the cost of enzymes down, which is now accomplished, but still requires research to tailor the enzymes to the particular biomass, and which needs a higher yield ( a 4% ethanol yield means we are using more energy than we get as fuel - Corn starches yield 15% or so - perhaps that is breakeven?)
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