Monday, July 30, 2007

Fuel for thought

As some of you may know, I've been involved in developing an Algae-based cellulosic ethanol plant in our region. Let me be clear at the outset: cellulosic ethanol is only a stop-gap. It can only provide a percentage of our liquid fuel needs. But it can reduce our dependence on petroleum by whatever percentage that is developed, and it's well worth doing. What makes ethanol so controversial is that current production is predominantly corn based, which has a major impact on food supply. Algae based ethanol doesn't present that problem, which is why I've been working on it.

But as I've expanded my research, I'm now working on a different idea: Butanol. As you can see in the diagram above, Butanol closely matches gasoline in BTU's and octane. It can be used to fuel current gasoline engines without any modification or blending.

Butanol has many superior properties as an alternative fuel when compared to ethanol. These include:

  • Higher energy content (110,000 Btu’s per gallon for butanol vs. 84,000 Btu per gallon for ethanol). Gasoline contains about 115,000 Btu’s per gallon.
  • Butanol is six times less “evaporative” than ethanol and 13.5 times less evaporative than gasoline, making it safer to use as an oxygenate in Arizona, California and other states, thereby eliminating the need for very special blends during the summer and winter months.
  • Butanol can be shipped through existing fuel pipelines where ethanol must be transported via
    rail, barge or truck
  • Butanol can be used as a replacement for gasoline gallon for gallon e.g. 100%, or any other percentage. Ethanol can only be used as an additive to gasoline up to about 85% and then only after significant modifications to the engine. Worldwide 10% ethanol blends predominate.

The main challenge is to produce it at a cost that is economically competitive. Currently Butanol costs about $3.70 per gallon (although that is based on using corn as the source stock). If more efficient enzymatic fermentation of algae can be developed, that cost could be greatly reduced.

One indication of the potential for Butanol is that the oil company BP is putting $500 million into an experimental Butanol plant: If a major oil company is spending that much money on it, there's a good amount of potential.

So I'm busy doing more research. I aced biochemistry in college, but I'm no biochemist so it's slow going.

Your thoughts?


whig said...

What are the environmental impacts of Butanol?

whig said...

Is the low vapor pressure good or bad?

pygalgia said...

LVP is good, as it allows safer transportation. Enviormentally, the CO2 reduction is only about 2-3%, so it's far from ideal. I should have added that in the long term we need to move beyond internal combustion based transportation, but if we're looking for ways to reduce petroleum dependance in the short term then Butanol has a lot of potential.

SweaterMan said...

Wikipedia has a good low-level background:

Jess Wundrun said...

What is the source of the algae?

pygalgia said...

Grown in ponds, and used to sequestor the co2 from the distillattion. We're planning roughly 250 acres.