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PostPosted: Thu Jul 28, 2005 6:52 pm 
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For those hoping to contribute to the latest alternative to non-renewable energy sources, this article is sobering. Obviously it's not without controversy, but it's certainly noteworth.

Ecologist: Ethanol, Biodiesel Energy Wasters

- Bill


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 Post subject: I wonder...
PostPosted: Thu Jul 28, 2005 7:26 pm 
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how much energy it takes to produce a gallon of gasoline. I kinda wish they mentioned that in the article as well. Admittedly they've concluded that all of these fuels take more energy to produce then they are capable of supplying. But I'm sure it take a certain amount of energy to convery raw crude oil into gasoline and clean it up.

Just out of curiosity more than anything...


cheers,

chewy


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PostPosted: Thu Jul 28, 2005 7:39 pm 
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Here (http://encarta.msn.com/encyclopedia_761 ... oline.html) they describe the gasoline production process, but no mention of how much energy it takes to produce (obviously a fraction of return energy or we wouldn't be using it):

Quote:
Gasoline, mixture of the lighter liquid hydrocarbons used chiefly as a fuel for internal-combustion engines. It is produced by the fractional distillation of petroleum; by condensation or adsorption from natural gas; by thermal or catalytic decomposition of petroleum or its fractions; by the hydrogenation of producer gas or coal; or by the polymerization of hydrocarbons of lower molecular weight. Internal-Combustion Engine.

Gasoline produced by the direct distillation of crude petroleum is known as straight-run gasoline. It is usually distilled continuously in a bubble tower (Distillation), which separates the gasoline from the other fractions of the oil having higher boiling points, such as kerosene, fuel oil, lubricating oil, and grease. The range of temperatures in which gasoline boils and is distilled off is roughly between 38° and 205° C (100° and 400° F). The yield of gasoline from this process varies from about 1 percent to about 50 percent, depending on the petroleum. Straight-run gasoline now makes up only a small part of U.S. gasoline production because of the superior merits of the various cracking processes.

In many parts of the country natural gas contains a percentage of natural gasoline that may be recovered by condensation or adsorption. The most common process for the extraction of natural gasoline includes passing the gas as it comes from the well through a series of towers containing a light oil called straw oil. The oil absorbs the gasoline, which is then distilled off. Other processes involve adsorption of the gasoline on activated alumina, activated carbon, or silica gel.

High-grade gasoline can be produced by a process known as hydrofining, that is, the hydrogenation of refined petroleum oils under high pressure in the presence of a catalyst such as molybdenum oxide. Hydrofining not only converts oils of low value into gasoline of higher value but also at the same time purifies the gasoline chemically by removing undesirable elements such as sulfur. Producer gas, coal, and coal-tar distillates can also be hydrogenated to form gasoline. Hydrogenation.

For use in high-compression engines, it is desirable to produce gasoline that will burn evenly and completely in order to prevent knocking, the sound and damage caused by premature ignition of a part of the fuel and air charge in the combustion chamber of an internal-combustion engine. The antiknock characteristics of a gasoline are directly related to its efficiency and are indicated by its octane number. This is a rating that describes performance of a fuel in comparison with that of a standard fuel containing given percentages of isooctane and heptane. If the performance of the rated fuel is the same as that of a standard fuel with a certain percentage of isooctane, the octane number given the rated fuel is the same as the percentage of isooctane in the standard fuel. The higher this number, the less likely a fuel is to cause knocking. Cracked gasoline has better antiknock characteristics than straight-run gasoline, and any gasoline can be further improved by the addition of such substances as tetraethyl or tetramethyl lead. Since it was discovered, however, that the emission of lead from gasolines combined with such additives is dangerous to living beings—among other effects, raising blood pressure—research on new ways to reduce the knocking characteristics of gasoline was intensified.

Low-lead gasolines were introduced in the early 1970s as a result of increased public concern about air pollution. After 1975 all new automobiles in the U.S. were equipped with catalytic converters to reduce the engine's emission of pollutants. Because even low-lead gasoline “poisons” the catalyst, the proportion of leaded gasoline in the U.S. declined from 73 percent of the total supply in 1976 to less than 10 percent in 1990. (European countries were moving more slowly in this same direction.) The Clean Air Act of 1990 required oil companies to make available cleaner gasoline with a higher oxygen content in polluted urban areas, beginning in 1992. In the late 1990s many environmentalists called for the increased use of gasohol and cleaner-burning natural gas. In addition, in 1999 and 2000 two Japanese automakers introduced hybrid electric-gas vehicles to the U.S. market that greatly increased fuel efficiency and lowered emissions of air pollutants. Several U.S. automakers also began intensive work on vehicles powered by fuel cells that used no gasoline at all. In 2003 President George W. Bush called for the development of a fuel-cell car by 2019. Electric Car; Fuel Cell.



Of couse this brings up another interesting question, which is how much of the energy spent in burning in bio-feul is actually transfered to powering the vehicle and how much is wasted in the form of heat? I would imagine these feuls are no better than gasoline in this respect (combustion engines waste a lot of this energy).

cheers,

chewy


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PostPosted: Thu Jul 28, 2005 7:45 pm 
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Good point... It does make you wonder when you see the great lengths that people go to (offshore drilling, pumping water underground, long pipelines across the Alaskan landscape, etc.) to get the stuff.

The thing that makes petroleum drilling such a net producer of energy is the energy density of the original product, as well as the work done to produce a unit (barrel) of it. When you think about it, a barrel of oil probably reflects the capture of years and years of sunlight on a given area of land. With ethanol and biomass, we have to do it in real time - a much shorter interval.

We haven't discovered that silver bullet yet, and we may not for some time. In the mean time, attaching energy capture to existing processes is probably the better way to go about it. If you happen to have a lot of extra pig schit around... And some extraordinarily simple approaches (i.e. burning the biomass at the soruce) may be the most efficient way to capture the energy in it.

And that gets us back to a unsolved problem for automobiles - finding a way to make energy assets more fungible. Hydrogen is the big dream, but it's a long way from reality.

The silver bullet(s) very well may be something we haven't conceived of yet.

- Bill


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PostPosted: Thu Jul 28, 2005 8:12 pm 
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chewy wrote:
this brings up another interesting question, which is how much of the energy spent in burning in bio-feul is actually transfered to powering the vehicle and how much is wasted in the form of heat? I would imagine these feuls are no better than gasoline in this respect (combustion engines waste a lot of this energy).

The efficiency of the best gasoline engines is 20 to 25 percent (with high compression engines using high octane fuels). Diesel engines have efficiencies of slightly over 40%.

Pure biodiesel has an energy density greater than gasoline and a bit less than typical petroleum-based diesel. Most engines today that use traditional diesel aren't tuned to use pure biodiesel, but instead use a mix of petroleum and bio-based diesel. An engine tuned to run on pure biodiesel fuel probably would yield efficiencies just less than petroleum-based diesel engines, although this is just a guess. Pure biodiesel has issues (turns to jello) when the weather gets too cold. Additives could change these properties, but there is the source problem. Would they be petroleum-based additives?

Ethanol is another story altogether. It too generally is mixed with gasoline, and not used as a pure substance. Pure ethanol has issues when the weather gets too hot, causing vapor lock in typical engines. More tricks would be needed to rely on pure or mostly pure ethanol.

- Bill


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PostPosted: Thu Jul 28, 2005 8:24 pm 
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"Of couse this brings up another interesting question, which is how much of the energy spent in burning in bio-feul is actually transfered to powering the vehicle and how much is wasted in the form of heat? I would imagine these feuls are no better than gasoline in this respect (combustion engines waste a lot of this energy)."

"The efficiency of the best gasoline engines is 20 to 25 percent (with high compression engines using high octane fuels). Diesel engines have efficiencies of slightly over 40%."

Bill: Where did you get this info? It looks way too high.

BioDiesel is somewhat in the same class as regular diesel in energy. As I recall the very best efficiencies available from diesel engines is somewhat below 25%. So, over 3/4 of the energy is lost to heat, friction and windage.

Gasoline engines are much less efficient than diesel engines and are rated somewhere in the mid to high teens. The exact % I do not know.

When I was involved in the paper/forest products industry we spent a lot of time trying to get the most energy out of assorted fuels from natural gas to biomass to garbage to tires.

Some biomass was free as a result of the process of making paper. This could be bark, branches and leaves, sludge from the water treatment plant or the volatile chemicals trees produced. A lot of things like turpentine, tars, and the natural glues that hold wood fibers together come out of the paper making process. Burning all this stuff is what gives paper mills their delightful aroma. Paper mills waste nothing!

The most efficient energy production was from combined cycle turbine generators where waste heat was used to boil more water for the steam turbines. About the best result there was in the lower 30% range. But, that is better than even a huge coal fired utility can achieve in a simple cycle.

Some biomass (sludge is a good example) actually had a 0% net energy return but the benefit of reducing the volume by 95% (ashes) made it worth the effort. So, fuel was burned in the combustion boilers just to make the sludge go away!

Burning garbage looked like a good idea for a while, and some plants still do it. However, in certain urban areas that fuel supply was controlled by what we know of as 'the mob'. Many major companies lost interest as a result. But in addition to creating energy, the garbage mass is greatly reduced. In some areas that solved landfill problems.

Tires are also burned. They contain a lot of oil and carbon so produce quite a bit of energy. Lots of tires lying around as well so there is a double benefit. It is also possible to literally shred and then 'cook' tires down and recover much of the petroleum content.

The big problem of burning waste like garbage and tires is the emissions. Cleaning the exhaust stack gasses of soot, heavy metals, sulpher, NOX etc make this a very expensive proposition and is not practical for small operations.

Rich

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PostPosted: Thu Jul 28, 2005 8:32 pm 
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Rich wrote:
Bill: Where did you get this info? It looks way too high.


It seemed a bit high to me too, Rich. I'll give you my source.

Internal Combustion Engine

I take it to be just the engine, and not the entire automobile.

- Bill


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PostPosted: Thu Jul 28, 2005 8:58 pm 
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I'm going to check with the GE locomotive engine plant. The sizes they build are probably the most efficient. I hope they will respond to a retiree.

Rich

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PostPosted: Thu Jul 28, 2005 9:06 pm 
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Quote:
Rudolf Diesel shocked reputable scientists and inventors at the 1900 World's Fair in Paris by pouring peanut oil directly into his newly unveiled diesel engine. While at the time revolutionary, no idea could have been more natural for an innovator who had spent his childhood in the agricultural provinces of France and Germany. Throughout his career, Diesel promoted the benefits of agricultural fuel. In a speech given in Germany in 1911, he declared, "The diesel engine can be fed with vegetable oils and would help considerably in the development of agriculture of the countries which use it."

Two years later, Diesel was on a trip across the English Channel when he disappeared. Mysteriously, his body was never found. The English newspapers suggested that he had been assassinated by foreign agents.

After Diesel's death, the idea of fueling engines with vegetable oil was quickly and quietly swept under the rug. His original designs were modified and diesel engines were made to run on the cheapest, most abundant fuel available: petroleum.



Looks like the powers that be got to him way back when.
I wonder how things may have been different?
Imagine how different the farm industry would have been.
F.

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PostPosted: Thu Jul 28, 2005 9:08 pm 
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Biodiesel is easily made from vegetable oil, alcohol and a catalyst, through a process called transistorification. The only by-product is glycerin, which can be used to make soap or any one of thousands of other products. Biodiesel can be used in any diesel engine and burns 75% cleaner than petroleum diesel fuel. It can be made from any vegetable oil, including soy, canola, sunflower, hemp, coconut and even used cooking oils or animal fat. It is highly lubricating, which actually makes it better for diesel engines than diesel fuel. But the best thing about biodiesel is that it requires absolutely no engine modifications. To use it, you just pour it into the fuel tank. It even mixes with regular petroleum diesel fuel.



Doesn't sound that tough to make.

F.

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PostPosted: Thu Jul 28, 2005 9:25 pm 
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"I take it to be just the engine, and not the entire automobile."

Yes, this could be a 'gross' not 'net' efficiency. Driving cooling pumps, fans, fuel pumps etc will drag down overall efficiency.

Rich

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PostPosted: Thu Jul 28, 2005 9:53 pm 
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But the best thing about biodiesel is that it requires absolutely no engine modifications. To use it, you just pour it into the fuel tank.

You could do that, but it wouldn't be wise.

Engines designed to run on petroleum-based diesel "expect" a certain energy content. Pure biodiesel has less. There are other issues as well, such as its solvent properties and high gel point.

See Biodiesel at Wikipedia.org. Another interesting and detailed reference can be found at the Technical Handbook for Marine Biodiesel. For example...
Quote:
In the 1998 study at the Southwest Research Institute on Biodiesel effects on diesel engine performance, engine power in the 1997 Cummings truck engine operating on the B-20 blend was at 98.5% of the power attained with low sulfur No. 2 diesel. At 100% Biodiesel, the engine generated 92% of the power. For a Detroit Diesel truck engine (1997), the power was 98% with the B-20 and 92% with the neat Biodiesel.

- Bill


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PostPosted: Fri Jul 29, 2005 2:37 am 
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The solvent properties keep the system running clean

There were concerns over ten years ago with some rubber parts in the fuel system but they no longer use those materials.

It is interesting when you look it up as there are different "recipes" that people have online. Obviously some large firm would have to produce it for it to be viable. But if college kids are doing it, can't be too difficult.
Currently I don't know what restaurants do with their grease traps but I bet they pay to get it pumped out.

So we have a waste product people will pay to get rid of.
A renewable resource can also be used.
A product not too difficult to produce.
An alternative fuel people will pay for.

As prices rise in not only diesel but home heating fuel this becomes more of a possibility.

F.

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PostPosted: Fri Jul 29, 2005 2:19 pm 
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There's a bit of brilliance in finding a healthy, bio-friendly use for the crap they serve at most fast-food restaurants. And heck...you could even send the discharge from liposuction clinics off to run your diesel Jetta. (Eeeeaauuuu!!!! 8O )

Another interesting feature gets into the whole hazard thing that Rich and I joust about. Hybrids have their high-voltage DC hazards. Fuel cells - if they every become viable - are laden with all kinds of crazy high pressure or high explosivity issues unless they find a way to bond the hydrogen to something that makes it safe and convenient to store.

But biodiesel has an extremely high flash point. Unless you inject it into a hot engine block at high pressure, it pretty much is just a greasy mess. And absent the chemicals they need to keep it from turning to jello any time you have a light frost outside, you could spill it in your back yard and not worry about it.

I agree, Fred, we need more neat ideas like this. What's not to like about finding a use for waste? In the old midwest, windmills powered farms one propeller at a time. We could do the same with grease using a little Yankee ingenuity.

The only thing we need to remember is that this will barely put a dent in our total energy consumption. We can't turn an entire economy around to meeting all our transportation needs this way. There are myriad issues.

- Bill


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PostPosted: Sat Jul 30, 2005 2:36 pm 
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Yes, bio-diesel can jell, but petro-diesel requires additives to prevent jelling also. In many places, you are prevented from using #2 home heating fuel to run in a vehicle because of government tax breaks and regulations, but one of the cost savings for heating fuel and farm diesel is to reduce or eliminate the anti-jelling additives. A pint bottle of anti-jell will treat around 1000 gallons of diesel and it's not that expensive to buy. (Sorry, I don't know if it's petro based or what)

So what if bio-diesel burns at 92% efficiency?!?! When the price of petro-diesel becomes double what the price of bio-diesel can be sold for, I don't believe that folks will worry so much on whether they're getting 200hp or only 184hp to travel, farm, run generators, heat their homes... :roll: At that point, the difference is "in the noise" because by it's very nature when talking about diesel engines, we're not discussing race cars anymore. When looking at most IC engine applications (besides racing, which won't be something that will be a concern when the crude oil runs out), the engine being used has a much higher output than required for the job anyway. Reducing the output by less than 10% from using a fuel that is available when petro-diesel becomes UNavailable in the future, probably won't be much of a concern. (Just because there is still some crude oil left in the world, at some point when the reserves get low enough, governments are going to start keeping that petro-fuel for their own use and the average person is going to be left to fend for themselves...)

At the current prices, bio-diesel is a competitive alternative to petro-diesel... and there certainly isn't any indication that prices are going to drop, rather the opposite. The higher the price of petro-diesel, the more attractive bio-diesel. With the efficiency difference of 8-10%, I would hypothesize that bio-diesel will be more attractive at the point that it is 15+% cheaper than petro-diesel. But as I said, when petro-diesel isn't available to the masses any more, will there really be this much concern over the lose of a few horse-power?


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