Fuel always a concern for the railways..

[Anonymous]

I'm not quite sure how, but I suspect "tradeoffs" in the exhaust gas makeup of EGR diesel engines may be at a point of diminishing returns and are more politically driven.

In the past, diesel combustion produced CO2 and high particulate, but other gases were lower, now, it seems, particulates are low but engines are producing CO and other gases are higher.

I'm not sure how but do know that the combustion process to produce CO2 is different from the process that produces CO, the external differences being heat and pressure.

[Anonymous]

QUOTE: Originally posted by Overmod

FM -- my understanding, perhaps incorrect (but I doubt it is ;-}) is that one of the principal drivers of the ethanol process is that it's biologically driven. Are there 'safe' microorganisms that can catalyze generation of the higher alcohols directly, or are we looking at synthesis from natural gas via the same general processes used for methanol?

Can you provide direct links to references for the production methods you mentioned? I, for one, would like to see their protocols...

OM, the one I am most familiar with is the MixAlco Process developed by Mark Holtzapple of Texas A & M. Here are two links with brief descriptions of the process:

<http://www.ct.ornl.gov/symposium/22nd/index_files/oral03.07.htm>

<http://www.fuelandfiber.com/Archive/Fuel/Research/Holtzapple/holtzapple.html>

You can get a more in depth description if you want by searching for "MixAlco" and/or "Mark Holtzapple".

The MixAlco process has the advantage of both using biowaste as a prime feedstock (rather than higher priced grains), and has a solvent recovery rate of over 50%. Other methods such as using acid fermentation of producing higher chain alcohols from either grains or cellulose only recover a fraction of the solvent compared to the MixAlco process.

The one paradox of MixAlco is that the intermediary products (e.g. acetic acid) are of a higher value than the end product of fuel grade alcohols without subsidies. Also, to get the alcohols from the ketones, the ketones must be hydrogentated, which does use natural gas.

[PNWRMNM]

Because it is an alternative market for corn. By removing some of the corn supply for ethanol production price of corn should go up. It is a hidden subsidy for corn farmers. If you pay attention to who supports ethanol subsidy in US it is always corn belt legislators. Follow the money.

Mac