Jan
29
How To Measure Some Energy Judgments
January 29, 2010 | 6 Comments
Robert Rapier, bless ‘em, attracted Frank Weigert a retired DuPont chemist to express his views on the pathway to renewable fuels. Odd, Mr. Rapier is quite the one to skewer the biofuel field generally, relying on his considerable practical knowledge without investigating the paths research can use in getting to new developments. Mr. Weigert had sent Mr. Rapier an email describing his views on a pathway that could lead us away from our dependence on petroleum. Rapier in turn asked if the material could be turned into an essay for others to read.
For our purposes Mr. Weigert offers biofuel definitions. The narrative is exactly on point and done such that it can be used to assist people in understanding what’s going on. Its educational grade, I quote with some edits:
The differences in chemical nomenclature and more conventional terms all too often confuse non-chemists. Oil as an ingredient in salad dressing is not the same oil as a synonym for petroleum.
Green plants make nucleic acids, proteins, hydrocarbons, carbohydrates, and lipids. Only the latter three need concern us as fuel precursors. Hydrocarbons have only carbon and hydrogen in their structure. (Other) Examples include natural rubber and other materials made from isoprene oligomerization.
Carbohydrates have formulas around (CH2O) n: Carbo (C) – hydrates (H2O). Glucose, C6H1206, is a monomer. Sucrose is made from glucose and another sugar fructose with the loss of one water molecule. Both sugars are soluble in water. Polysaccharides such as starch and cellulose are insoluble in water. Yeasts ferment soluble sugars to ethanol, an alcohol. The technology to ferment (some) insoluble carbohydrate polymers practically (at commercial scale) does not yet exist.
Lipids are esters of the alcohol glycerin and long-chain fatty acids. Transesterification with short chain alcohols such as methanol or ethanol converts these lipids to glycerine and esters generically known as biodiesel. Biodiesel is not a hydrocarbon (its still a carbohydrate).
Hydrocarbon (formation) reactions are generally many orders of magnitude faster than the reactions of polar molecules such as those involving alcohols or esters. That means that the equipment required to reform hydrocarbons is much smaller than that required to ferment carbohydrates to ethanol or transesterify lipids to biodiesel. Hydrocarbon chemistry does not require a solvent. Fermentation must be carried out in water, and yeast generally can only produce an ethanol concentration of 10% or so. The ethanol must then be separated from a large excess of water. Transesterification to make biodiesel is an equilibrium process that will not go to completion without a large excess of the small chain alcohol. That means large equipment for separation and recycling. While a hundred or so refineries provide all the transportation fuel America uses, many thousand fermentation or biodiesel facilities would be needed to produce the same amount of fuel.
Mr. Weigert concludes that investments to obtain a carbohydrate economy like methanol and ethanol are going to be quite high, then asking why bother when using hydrocarbons like gasoline and diesel when both can be produced from biological materials?
Before answering lets give Weigert and Rapier credit, Weigert educates simply and accurately about the chemistry basics. Thank you to both of them.
The question’s first answer is in a whole different field – economics, meaning markets and the consumers that determine the course. Everyone, no matter where geographically or where on the current consumption scale, want more energy powered assistance for raising their standard of living. The job here, and hopefully in business and government is to drive the cost of energy and fuel lower and the tools that use energy and fuel to higher efficiency. Driving a distance in whatever style is chosen isn’t decided by the fuel or energy choices alone.
Weigert says, “Consumers should not have to change anything.” Well, not compulsorily, price and feature incentives are better tools. But change is inevitable, it’s the policies that governments form and the reactions in business that create prices and incentives – a fact lost on the U.S. government for now. Business is just as guilty in the failure; lobby work is mostly about maximizing the status quo, blanking developments, and bleeding out advantages from the whole economy. Throw in the regulatory battles and gridlock is quite understandable.
That might be the best consumers can expect, but it does produce a distorted economic landscape. People will fill that landscape however its formed with the things they want. Maybe the U.S. ethanol industry has excess advantages, but the drive to light molecule fuel cells using things from the hydrocarbon methane to the alcohols methanol and ethanol offer prodigious amounts of energy stored as fuel that when compared to fossil oil products can be quite advantageous. At fuel cell efficiencies with some buffer storage in batteries or capacitors, the combustion path has an effective competitor offering features and prices for consumers to measure.
The question’s second answer is that hydrocarbon formation from biomass is a field with several contenders. Pyrolysis, the oldest, might lead the field but others have great potential as well. The business may find that extracting the sugars and then engaging into a hydrocarbon formation process yields the maximum amount of commercial products at the lowest cost. The field also is faced with the costs to form hydrocarbons to the desired molecules needed in the market. It’s just not simple, and the market for products using fuels is going to go for efficiency and the larger hydrocarbons as jet and diesel, so far at least, are destined for combustion to convert the stored energy into work. That is getting to be a disadvantage in the largest markets. The combustion market will exist; flight, heavy equipment and other markets may well choose the pure hydrocarbon path. Most machines as tested by the airlines and military get along fine with biofuel carbohydrates, biofuel hydrocarbons, petroleum hydrocarbons and appropriate blended combinations. Biofuel hydrocarbon production plants are going to be needed in the thousands as well.
Humanity’s principle challenge is to preserve and improve itself. History is replete with attempts to do such things with power at the pinnacle forcing it down to the masses. It is clear to anyone curious enough to look – that method can get people killed by the millions. What does work is for the masses to have the maximum choices available and let the intelligence of the billions do its magic.
Keep an eye on the energy and fuel landscape. There are choices with prices and features that are going to change and get much, much better in the coming years. Mr. Weigert offers a useful lesson, but the important lesson is what you find from making your own choices.
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[…] Today found this great post, here is a quick excerpt : Energy judgment needs basic chemistry facts offered by Frank Weigert. We check them & answer Weigert’s question with a review about energy and fuel choice. Read the rest of this great post Here […]
[…] 2, 2010 Energy Talks I have come to admire Robert Rapier; just last week we had a look at one of the best pieces he’s p… As if there is some signal a good turn deserves a bad one, Mr. Rapier came up with a post that is […]
Keep posting stuff like this i really like it
Let me clarify what I mean by “the consumer should not have to change anything” by using two examples from the television industry.
60 years ago television broadcasting was all black and white. Hardware manufacturers felt there was a demand for color broadcasting. Each company initiated its own research program and they all came up with mutually incompatible solutions. The FCC wisely realized that allowing all of them on the market would produce chaos. One manufacturer stood out from all the rest. They would broadcast a signal which separately encoded the picture’s intensity and hues. What this meant was that existing sets would receive a black-and-white picture while new and more expensive sets would receive the full color image. A consumer who didn’t want color did not have to change anything. In fact if the consumer had stockpiled vacuum tubes, that set would have worked into the 21st century.
When the FCC wanted to switch television from analog to digital broadcasting, there was no way existing NTSC sets could deal with the new ATSC signal. Consumers who still wanted to receive over the air broadcasts had to do something. They could pay for cable or satellite. They could buy a new ATSC set. Additionally, the government mandated that the industry manufacture converter boxes and gave coupons to consumers so they could acquire them for essentially nothing. The consumer could then insert the converter box between their antenna and their old set and continue to use it.
The ozone friendly HFCs were drop-in replacements for the CFCs. Consumers did not have to buy a new air conditioner or a new refrigerator just because they needed to recharge their coolant.
Unleaded gas was not a drop-in replacement for leaded gas. Filling stations had to maintain separate pumps for a generation until most of the old cars which used leaded gas went to the junkyard. To make sure consumers didn’t use cheaper, leaded gas in their newer cars, the tanks of newer cars would not accept the nozzles pumping leaded gas. Consumers had to pay attention to which pump they used to fill their tank. The changeover took a generation.
Many of the solutions to Hubbert’s Peak and global warming require major actions on the part of consumers. Electric cars are not drop in replacements for what Detroit produces now. Ethanol is not a direct replacement for gasoline. Biodiesel IS a direct replacement for petroleum-based diesel.
The transition will go a lot smoother if the fuel of the future is compatible with the cars, trucks and planes of the present.
“Biodiesel is not a hydrocarbon (its still a carbohydrate).”
WRONG! Biodiesel is an ESTER. While esters do contain carbon, hydrogen and oxygen, the term carbohydrate is generally reserved for compounds close to the formula [C(H2O)]n
I do not advocate factories for “hydrocarbon formation from biomass.” I am suggesting we carefully evaluate green plants that make hydrocarbons as part of their natural metabolism. These hydrocarbons would be drop-in replacements for petroleum to produce transportation fuels and drop-in replacements for coal to produce electricity. Much existing investment would remain useful. Algae grown in the ocean would not compete with food production on land. They would not disturb the soil. Converting carbohydrates to hydrocarbons by either pyrolysis, fermentation or multi-stage processes such as gasification/Fischer-Tropsch, require much new investment.
I disagree with the statement that “Most machines as tested by the airlines and military get along fine with biofuel carbohydrates.” Carbohydrates have far too low an energy density to compete with hydrocarbons. Even ethanol has only 70% as much energy as a hydrocarbon. Carbohydrates are even worse.
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