American Chemists compare FT (coal based fuel) and biodiesel NOx

[NNadir]

This study explores the diesel injection and combustion processes in an effort to better understand the differences in NOx emissions between biodiesel, Fischer-Tropsch (FT) diesel, and their blends with a conventional diesel fuel. Emissions studies were performed with each fuel at a variety of static fuel injection timing conditions in a single-cylinder DI diesel engine with a mechanically controlled, in-line, pump-line-nozzle fuel injection system. The dynamic start of injection (SOI) timing correlated well with bulk modulus measurements made on the fuel blends. The high bulk modulus of soy-derived biodiesel blends produced an advance in SOI timing compared to conventional diesel fuel of up to 1.1 crank angle degrees, and the lower bulk modulus of the FT diesel produced a delay in SOI timing of up to 2.4 crank angle degrees. Compared to conventional diesel fuel at high load, biodiesel fuel blends produced increases in NOx emissions of 6-9% while FT fuels caused NOx emissions to decrease 21-22%. Shifts in fuel injection timing, caused by bulk modulus differences, were largely responsible for the NOx increases, but pure FT diesel produced lower NOx emissions than expected on the basis of SOI alone.

From the upcoming issue of Energy and Fuels: http://pubs.acs.org/cgi-bin/abstract.cgi/enfuem/asap/abs/ef049702q.html

It is worth noting that engines have not been optimized for biodiesel, and that NOx is subject to catalytic decomposition. The waste products from coal, heavy metals, sulfuric acid, etc, do not go away under any circumstances, nor of course, does the CO2.

The full article (accessible only to journal subscribers) refers only in passing to the lowest emission diesel fuel there is, dimethyl ether (DME).

[Terry in Austin]

1. Let's see if we've got it in English

Emissions performance

• good: FT diesel
  
• better: biodiesel
  
• best: dimethyl ether
  
• recommended: tune your engine to suit your fuel
  

Is that it?

Interesting stuff, thanks -- been reading some pretty encouraging reports lately about DME.

[NNadir]

2. That's almost how I would put it, Terry.

I have a little trouble with "good" and FT diesel, since the most likely source for FT diesel is (long term) coal, which is, by far, my least favorite fuel.

For FT diesel, to the extent that is possible to obtain FT diesel from other carbon sources, we might say "fair."

DME is about the best chemical form of energy storage I can imagine, if only for its flexibility and cleanliness.

[Coastie for Truth]

3. Coal is NOT My Least Favorite Form of Fuel

- If anything is worse then coal it's oil sands. I think oil sands are even worse then FT.

(I grew up in and worked in two FT pilot plants in college - then I was fortunate enough to get a summer and p/t time in a National Lab - nuke power)

[NNadir]

4. Well, to be frank, I don't know the oil sands industry.

I routinely oppose all fossil fuels use under the circumstances, including methane.

I don't believe that the oil sands industry is all that large right now. It may be someday, but it is not now. For the time being, intending no disrespect for your point, I think I'll focus my hatred on coal. I am perfectly willing to hate oil sands - and certainly I oppose their development - at a later date, but coal is already killing us.

[Coastie for Truth]

5. Oil sands is the latest "Big Oil" salvation from "Peak Oil"

1. We can on polluting our earth and burning up our resources in our Hummers.

2. Oil sands next door in Canada.

3. Post refinery - same infrastructure as gasoline.

4. More of an insult to the environment then coal mining and F-T. (I grew up in coal country - and used to drive along the coal corridors of I-79 and I-70)

5. Provides another excuse for the "Junk Bond" rated Big Three to "Do Nothing" about fuel economy and to keep resisting increasing CAFE.

WATCH FOR THE MEGA LOBBYING AND MEGA PR FOR OIL SANDS

BIG THREE

BIG OIL

BUSHIES